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Sustainable Environmental Protection Using Modified Pit-Latrines
Abstract
Pit-latrines are on-site excreta disposal facilities widely used as anaerobic accumulation system for stabilizing human wastes like excreta, both in rural and urban settlements of developing countries. Flooding of pit-latrines is often a common phenomenon, especially in situations of high water table (HWT) conditions and during the rainy season, causing a health jeopardy to residents. The pits are not water-tight, the (ground )water can freely flow in and out of the pit, especially in HWT areas. This results in groundwater (GW) pollution and even surface water pollution in the neighbourhood and pits that are filling up far too quickly. With a growing concern of public health, GW pollution and the reuse of nutrients from human waste, there is a serious need to study and improve the pit latrines, especially those in HWT areas. Specifically, the scope of this thesis was to study the socio-cultural aspects of excreta disposal in Dar-es-Salaam City , to improve the understanding of the biological stabilization processes in anaerobic accumulation systems and to come up with proper operational guidelines for emptying practices. A literature research and the results of a survey on excreta handling amongst 207 households in 9 of the 52 wards of Dar es Salaam (Dsm.) presented in this thesis shows that 50% of the filling up of pits in Dsm. city is the result of HWT. Moreover almost 16,131 kgCOD/day from pit-latrines reach GW sources (Haskoning and M-Konsult, 1989). In this study an improvement of the pit-latrine was proposed using a plastic tank as pit. A 3000-liter experimental improved pit-latrine without urine separation (IMPLWUS) was constructed and monitored at a 10-person household in Mlalakuwa settlement in Dsm. , Tanzania . The influent to the reactor merely consisted of urine and faeces in the ratio of 1.3:1. The results obtained revealed that, after 380 days of use as a daily pit-latrine, the reactor content was not yet stabilized. 8000 mg/l dissolved COD (but only 100mg COD/l volatile fatty acids) were still present. Part of this dissolved COD was shown to be biodegradable signifying the need for further stabilization of the reactor content. It was hypothesized that the slow conversion of dissolved COD was due to the fact that the reactor was started with sludge that was not adapted to the resulting high ammonia concentration of 3000 mg N/l, i.e. the system in fact was still under start-up, and in subsequent runs of the reactor the conversion of dissolved COD would be much faster. For further evaluation of the conversion processes proceeding in the improved pit-latrine a simple mathematical model was used. The model results for the course of the concentration of the different COD components in the accumulating sludge in improved pit latrines receiving black water or night soil reactors, revealed that under tropical conditions 97% sludge stabilization is achievable within 1 year of reactor use. If 99% or more stability is desired, an accumulation period of 2.5 years is required or closing the reactor without adding any new materials for at least two weeks before desludging is necessary. When assuming Monod kinetics with k m = 1 gCOD × gCOD -1 × d -1 (Batstone et al,. 2003) it was calculated that for a latrine receiving black water as influent the specific methanogenic activity of the sludge after reactor closure will be about 0.12 g COD/g VSS/day. At a sludge concentration of 30 g VSS/l the volume to be left in the reactor as seed sludge for the subsequent runs is about 250 litres. Finally a short survey was done of existing composting latrines of the type of Ecosan toilets installed in Dar-es-Salaam. The survey revealed that high pH values occur (up to 10.4) in Ecosan toilets due to addition of charcoal ashes. High pH assist in the reduction of E-Coli and Ascaris eggs , but on the other hand could not allow biological degradation of waste. The separated urine in Ecosan toilets showed on average E-coli counts of 1525 no ./ 100 ml. indicating that urine was not adequately separated. In the light of sustainable development and in view of cost and economy, simple sanitary systems like Ecosan and IMPLWUS is the correct approach in Dar-es-Salaam and other tropical regions of developing countries. Sludge drying beds can be used for further stabilization of emptied sludge since they are cheaper than mechanized ones. Correct separation of urine in Ecosan toilets is necessary with the assistance of user health education. Comparing the Ecosan toilets to the improved pit-latrines it has to be concluded that both systems are promising alternatives to the conventional pit-latrine systems. However, both systems are still at their developing stage and require further work to provide a genuine sustainable solution for the disposal of human excreta in Dar-es-Salaam. The wealthy developed countries need to work with the developing countries in implementation of public sanitation aspects in low cost manner instead of advocating the expensive systems that will fail anyway.
... In general, pit latrines are regarded as accumulation systems, and the fate of the contents thereof is ignored until the pit fills and requires emptying. The few authors who have considered the processes in the pit agree that below the surface of the pit contents, the predominant mechanism of digestion, if indeed any occurs at all is anaerobic digestion (Mara, 1984;Still, 2002;Chaggu, 2004) although aerobic degradation processes may occur at the air interface (top surface). ...
... Construction and location Construction of walls and base of the pit Permeability of the walls and base of the pit (in lined pits) Construction of slab and superstructure of the latrine (does it allow water ingress?) Height of water , 1984;Franceys et al., 1992;Cotton et al., 1995;Norris, 2000;Still, 2002) Pit latrines can be regarded as fed-batch accumulation systems; slow accumulation of faeces, urine, water, anal cleansing material, and (depending on user habits) sand, leaves or household waste provide a constant flow of organic substrate for anaerobic digestion (Chaggu, 2004). Micro-organisms in the faeces, leaves, sand, previous pit contents or specifically added to the pit are the biological catalysts of the process, and CO 2 and CH 4 are the continuous gaseous products of the system. ...
... A number of literature sources provide information on the characteristics of urine and faeces. (Chaggu, 2004) presents a survey of available literature on the chemical composition of urine and faeces. Additional data has been obtained from Palmquist and Jönsson (2003) and Lopez Zavala et al. (Lopez Zavala et al., 2002), and the combined data is presented in Table 3.2. ...
... Due to data gaps for C emissions from UDDTs, we assumed the processes of biochemical degradation of solid matter -mainly of the easy degradable faeces -to be equivalent to open defecation (Winrock, 2008). In general, emissions from a UDDT depend on the amount of ashes that are used as part of the dry matter toilet additives (Chaggu, 2004). The addition of ashes raises the pH and a pH > 7 can suppress biodegradation of faeces, i.e. avoid CO 2 and CH 4 emissions, but promote ammonia losses (ibid.). ...
... • • Auxiliary calculations relevant for modelling included: o Determining the mean value of moisture in faeces and solid material when it leaves the UDDT, from data provided by Chien et al., 2001, and by an experiment conducted in Karagwe in March 2015; o Determining the mean value of moisture in faecal sludge in a pit latrine, from data provided by Bakare et al., 2012, Buckeley et al., 2008, Chaggu, 2004, Muspratt et al., 2014 o Determining the mean value of specific parameters when operating the sanitation oven from CaSa-pilot project, from values recorded in an experiment conducted in Karagwe in March 2015 (e.g. fuel consumption, residues of ash and char, evaporated water, etc.); ...
... o Determining density, moisture content, C-, N-, P-concentrations in FM of the mix of dry material used in the UDDT, based on data from CaSa, 2015, Chaggu, 2004, Venkataraman et al., 2004, Krause et al., 2016. Table B.9 summarizes all parameter values that we used in the MSS-model. ...
... The walls of the pit are not well sealed to prevent penetration (leak) of wastewater thus allowing wastewater to percolate into the soil representing one of potential source of groundwater contamination. According to Chaggu, (2003), the Feacal-Coliform count for samples taken from groundwater (boreholes) in Dar es Salaam capital city at depths between 1.8metres and 6.5metres the results indicated 3000 FC/100mls and 178FC/100mls respectively. This pollution is definitely due to seepage from pit latrines and septic tanks. ...
... Source separation system could be sustainable system for fertilizer production in Tanzania, such that nitrogen, phosphorus, potassium and organic matters from urine and faeces can be recycled and reused for agricultural purposes, in that way could improve the local economy and strengthen the local communities of Tanzania with food while the surpluses may be sold at the market. (Chaggu, 2003). ...
... The fertilizer from human waste source separation system consist low concentrations of heavy metals compared to chemical fertilizers and also require little or no chemical to treat. 142,676 tons in 1991 and 200,000 tons of which 25% was N, P, K in 1994 (Chaggu, 2003). ...
Waterharmonica concept is the Dutch initiative which emphasized the use of low technologies that can make bridge or fills the missing links between the quality of water sources and wastewater. It is emphasized the use of natural process “as post treatment ecological engineered” to treat wastewater using low techniques. Therefore Waterharmonica concept can be defined as the embodiment of the ambition to include ecological engineered “linking systems”, such as constructed wetland, as integral part of the design and extension of wastewater treatment plant. The linking system will act as natural post treatment of effluent.
The basic principle Waterharmonica concept is to treat or polish and reuse nutrients from wastewater for agriculture and aquaculture activities, consequently to increase the products as well as to conserve and reduce the pollution of water sources.
... There was no significant difference (p>0.05) in moisture content with sludge depth and between lined and unlined pits during both seasons. The average moisture content in unlined pits in the rainy and dry seasons falls within the range of 80% to 92% as reported by Chaggu (2004). In this study ( Figure 4) the moisture content showed a general increase with sludge depth because pits were located below the groundwater table. ...
... These forms are interrelated through microbial and chemical transformations. In this study, the results of total nitrogen obtained are greater and less than results reported by Chaggu (2004) and Lopez Zavala et al. (2002) respectively. Chaggu (2004) and Lopez Zavala et al. (200) reported 17,820 mg/kg and 60,100 mg/kg as total nitrogen concentrations in their studies respectively. ...
... In this study, the results of total nitrogen obtained are greater and less than results reported by Chaggu (2004) and Lopez Zavala et al. (2002) respectively. Chaggu (2004) and Lopez Zavala et al. (200) reported 17,820 mg/kg and 60,100 mg/kg as total nitrogen concentrations in their studies respectively. ...
Failure to quantify nutrients in feacal sludge usually leads to its poor disposal resulting into surface water and groundwater pollution. Therefore, this study was conducted to determine and model the distribution of nutrients in pit latrine sludge as a step towards reuse of available nutrients. Sampling was done at 0.0, 0.5, 1.0 and 1.5 m depths from 31 lined and 31 unlined latrines during rainy and dry season. Physico-chemical characteristics such as chemical oxygen demand (COD), dissolved oxygen (DO), moisture content, temperature and nutrients including ammonia, nitrate, total nitrogen, phosphorus and potassium were determined. Results indicated that COD, temperature and DO decreased and moisture content increased with sludge depth. There was no significant variation (P˃0.05) in nutrients and physico-chemical properties except COD. Strong correlations of R2Adj ˃ 0.85 were obtained between modeled and measured values. The relative root mean square error of the predicted nutrients was less than 10%. Results revealed that the model is good estimator phosphorus concentrations in lined pits followed by total nitrogen in unlined pits and nitrates in lined pits.
Keywords: Nutrients, faecal sludge, latrines, modeling, sanitation
... Fecal sludge collected from OSS systems is treated to prevent any negative impact on the environment or public health, both from its solid and liquid components (40). Finally, it is crucial to ensure the safe disposal of treated sludge, especially the portion that cannot be used to recover resources for reuse (61). Regenerating items for reuse is essential to ensure that waste is kept away from people and the environment. ...
... Urban families use unimproved toilet facilities in the vast majority (54%). An open-pit latrine is the most prevalent type of unimproved toilet, being utilized by 37% of households in towns and cities (61). Urban people suffer from a lack of urban constructions and, more frequently, water, sanitation, and hygiene services in many African nations, including Ethiopia. ...
Background: An essential component of environmental sustainability and sanitation is the management of dry toilets, especially waste disposal. Understanding the composition of the brown water from dry toilets, putting the proper composting technique in place, and guaranteeing safe disposal and reuse procedures are all necessary to handle the waste successfully. It has been discovered that brown water, sometimes known as feces, can be used for brick-making, fuel, fertilizer, and other purposes. Methods: This review focuses on dry toilet technology, management processes, and sanitation systems in Ethiopia and other underdeveloped nations. It utilizes secondary information and searches from Google scholars, Library catalogs, and Researchers to comprehend dry sanitation systems, including their implementation, use, and maintenance. Keywords used in the search include "in-situ treatment," "fecal sludge treatment," "fecal slurry management," and "brown water treatment." Results: The review used a total of 108 articles and books, agricultural research, and reports on the feces’ physical, chemical, and biological characteristics. It also discussed risks associated with the mismanagement of feces, including parasitic diseases in exposed humans. The main aim of the review was to develop an understanding of brown water uses, composition, and management and select the proper method of composting with dry toilets. Conclusion: Dry toilets in developing countries are utilized for ecological sanitation and agriculture, with feces potentially used as fertilizer. Utilizing feces as fertilizer is a sustainable, eco-friendly, and environmentally responsible practice that can increase productivity while maintaining a clean environment.
... The immediate emotional reactions from the 53 FGD participants upon seeing the displayed photos of the FS-derived products and accompanying oral descriptions were negative. These negative feelings could be explained by both limited knowledge about FS-RRR and persisting cultural norms and taboos toward human waste in Tanzania (Chaggu 2004). The quotes from two FGD participants exemplify how these norms are expressed in Tanzanian society: ...
... (Male in FGD, Keko) 'I would consume the product resulted from feacal sludge only if the source will be intentionally hidden or completely unknown to me. It is very disgusting if I realize its source is human faeces or urine.' (Female in FGD, Manzese) These feelings of disgust against the reuse of human waste are not limited to Tanzania; however, the majority of countries in the world are considered feacophobic (Chaggu 2004). Our analysis on peoples' preferences criteria for the different FSderived products shows that those products that have direct or indirect links to human contacts, ingestion or fear of foul smell score the lowest, because they trigger peoples' emotions of disgust and violate existing religious norms. ...
Resource recovery and reuse (RRR) of fecal sludge (FS) from onsite sanitation systems describes the concept of turning human waste into valuable end products. However, studies on peoples' perceptions of FS-derived products are still limited. Guided by the knowledge, attitudes and practices framework, and data from a survey of 395 households, focus group discussions and key informant interviews, this article explores how residents in three unplanned settlements of Dar es Salaam, Tanzania view FS RRR (FS-RRR). Results indicate that residents' knowledge about FS-RRR is moderately low. Moreover, residents generally have negative attitudes toward using FS-derived products, except for those not directly consumed, such as biogas or FS-briquettes. Additionally, only a few residents have engaged in any FS-RRR practices. We conclude that to increase local acceptance of FS-RRR will require significant efforts by a multitude of actors, not least to dispel myths linked to human waste, but also to raise awareness and demonstrate the benefits and safety of FS-derived products. The Tanzanian government must take the lead in this process and should start by prioritizing the improvement of fecal sludge management (FSM) to enable such a shift. HIGHLIGHTS
The existing knowledge, attitudes and practices on fecal sludge resource recovery and reuse among residents were explored in three selected unplanned settlements.;
Low-to-moderate knowledge of resource recovery and negative attitudes have been identified.;
Training, awareness campaigns, public participation and private sector involvement are recommended.;
... When looking at farming households in rural TZ, meanwhile, we find a variety of different biomasses used as cooking fuels, though firewood still clearly dominates (Grimsby et al., 2016). Furthermore, while septic systems are most common in peri-urban and urban areas, pit latrines are the most common sanitation system in rural areas (Chaggu, 2004;Cheruiyot and Muhandiki, 2014). The widespread installation of pit latrines from the 1940s, largely through 'development cooperation', has led to the abandonment of locally adapted recycling practices (Rugalema et al., 1994). ...
... contribution to nutrient recycling with approximately 60% and 40% of the total recoverable N and P, respectively. As a plausibility check, Chaggu (2004) assumed a C recovery rate of 100% for EcoSan, and justified this by the alkaline conditions in the UDDT, after adding ashes, which hinders biological degradation of faeces. Hotta and Funamizu (2006) determined that approximately 90% of total N contained in human excreta could be recovered by using an UDDT, which supports our estimations of a recovery rate of approximately 80% of total N only from urine. ...
Objective:
To compare those cooking and sanitation technologies most commonly used in north-western Tanzania with locally developed alternatives, with respect to (i) resource consumption, (ii) potential to recover resources, and (iii) environmental emissions. This study examines technologies at the household level, and was carried out using material flow analysis (MFA). The specific bioenergy technologies analysed include: three-stone fires; charcoal burners; improved cooking stoves (ICS), such as rocket and microgasifier stoves; and biogas systems. The specific sanitation alternatives studied comprise: pit latrines; two approaches to EcoSan; and septic systems.
Results:
The use of ICS reduces total resource consumption; using charcoal or biogas does not. The residues from microgasifiers were analysed as having a substantial recovery potential for carbon (C) and phosphorus (P). The fact that input substrates for biogas digesters are post-agricultural in nature means that biogas slurry is not considered an 'untapped resource' despite its ample nutrient content. Exchanging pit latrines for water-based sanitation systems places heavy pressure on already scarce water resources for local smallholders. In contrast, the implementation of waterless EcoSan facilities significantly promotes nutrient recovery and reduces environmental emissions, particularly through greenhouse gas emission and nutrient leaching.
Conclusions:
Recycled outputs from the triple energy-sanitation-agriculture nexus display complementary benefits: residues from cooking can be used to restore organic matter in soils, while sanitation residues contribute to fertilisation. The combination of microgasifiers and EcoSan-facilities is the most appropriate in order to simultaneously optimise resource consumption, reduce environmental impacts, and maximise recycling-based soil management in smallholder farming systems.
... The conversion of the acids results in a rise of the pH within the landfill and the leachate to reach more neutral values which is the ideal condition for methanogenic microorganisms and consequently the reduction of the biochemical oxygen demand, the chemical oxygen demand and the conductivity of the leachate. Methanogenic bacteria are very sensitive to a drop in pH, so that the digestion of waste is obviously a delicate balance between the rate of hydrolysis, acidogenesis and methanogenesis (Chaggu 2004). This is the longest stage of waste degradation in landfills during which significant amounts of methane are generated. ...
... Temperature is one of the major (key) variables influencing the digestion of waste in anaerobic reactors (Chaggu 2004). Many studies have proved that microbiological degradation rate increases with temperature until a certain maximum level is reached. ...
... These informal unplanned and unserviced settlements harbour the majority of the urban population. For example, they are the homes for 70% of the population in Dar es Salaam (Mato 2002;Chaggu, 2004), 77% in Blantyre, 80% in Luanda (Palamuleni, 2002) and 60% in Kampala (WSP/NWSC, 2000). They are characterized by, among other things, poorly constructed houses, poor sanitary conditions, lack or inadequate support services and lack of legal status as residential dwellings. ...
... According to Feachem et al. (1983), the estimated enterobacteria content based on diet for the Ugandan populationwhich is largely carbohydrate is on average10 8 cfu per gram of human excreta. The average daily body waste generation is estimated to fall within the range of 1400-1450 gram per person (Chaggu, 2004). Using an average of 1400 gram per person, the estimated pollutant loads from the pit latrines for the different zones are shown in Table 6. ...
... The development of informal settlements in the peri-urban areas of the cities has been reported. In these settlements where the majority of the urban population reside: 70% in Dares-salaam (Chaggu, 2004), 77% in Blantyre, 80% in Luanda (Palamuleni, 2002) and 60% in Kampala (WSP/NWSC, 2000) to mention a few, are characterized, among other things, by poorly constructed houses, poor sanitary conditions, lack or inadequate services and lack of legal status as residential dwellings. ...
... Estimated phosphorus and nitrogen loads from the solid waste (Table 6), considering the organic portion (about 80%) (peelings of cassava and potatoes have trace amounts of these nutrients), are based on an average composition of 1.1% nitrogen and 0.2% phosphorus of the dry matter content (ranges between 16-18%, an average value of 17% is used in the calculations) (Nambi et al., 2004). (Chaggu, 2004). Used a value of 1400gram/ca/d. ...
Effective improvement of the current poor environmental sanitation in peri-urban Kampala requires an understanding of pollutant characteristics (types, sources, locations and loads). As part of an on going study, this paper presents pollution characteristics in Bwaise III and challenges encountered during the period 2002-3. Findings show that pit latrines are a major source of pollution as far as pathogenic bacteria and nutrients are concerned (14.5E20 cfu TTC /yr, 41,775kgN/yr and 6,680KgP/yr). Drains on the other hand, though they have lower levels of nutrients (980kgTKN/yr and 80kgP/yr for sullage) are recipients of runoff, solid waste and faecal matter and hence a major problem in the area especially during the rains. The impact of these on the environment and community health are mutually reinforcing. Challenges encountered during the study have been overcome largely by dialogue. Management strategies and mitigation measures for these areas require the collective participation of communities, authorities and policy makers.
... Greywater composes 50-80% of residential wastewater generated from all of the house's sanitation equipment (except toilets) [6] and contains hazardous components which could get to a new host or face before disposal into receiving water bodies through similar transmission routes shown in [7] and [8]. This implies that, transmission is *Address correspondence to this author at the Ardhi University, P. O. Box 35176, Dar-es-Salaam, Tanzania; Tel: +255-754 367 662; Fax: (255-022) -2775391; E-mail: esnatchaggu@hotmail.com possible from greywater through flies or soil to hands, food or fluids, all the way to a new host if sanitation barriers or treatment measures are not instituted. ...
... Faecal Coliforms are pathogenic organisms whereby, their presence in the environment is a health risk and a treatment concern. [8] cited that "people as an "asset" for development often produce in secret human "waste" which is of public concern". Where present, it is an indication that excreta has come into contact with water or excreta has been haphazardly disposed of. ...
Greywater is wastewater emanating from domestic activities such as laundry, dishwashing, and bathing. This water can have useful on-site uses like irrigating landscape and vegetables in tower gardens. However, its user potential need to include quality studies for determining its safety and achieving public health and environmental protection. Lake Victoria receives greywater from Mwanza City environs and therefore, protecting it from greywater pollution is very important. This research work with study components including socio-economic and the quality of greywater is adding to the need of protecting the lake from pollution. The results, Faecal Coliforms values ranging from 12 to too numerous to count (count/100 ml.) and Total coliforms values of 17 to too numerous to count (count/100 ml.) are clearly showing that, the greywater available in Mwanza is not safe. Moreover, it is evident from the heavy metals' results from liquid samples that, the values are insignificantly very low (<0.01 mg/L for Pb and Cu). The pH values are ranging from 5.9 to 7.5 while the recommended World Health Organisation (WHO) range is 6.76 - 8.0. The research is proposing tower gardens as treatment facility for greywater in Mwanza City.
... 15 Rural and urban slum residents are at heightened risk due to the lack of basic sanitation facilities and proper waste disposal management. 16 The absence of latrines can expose children to diseases, parasites, and worms, further weakening their immune system. 17 Inadequate hygiene and sanitation not only threaten children's health but also impede their overall development and wellbeing. ...
Background
Basic sanitation services and practices are crucial for the well-being and health of a community. However, little is known about the determinants of basic sanitation services in Ethiopia, particularly in the study area.
Objectives
To identify the determinants of basic sanitation service coverage among households in the Shashogo district, Hadiya Zone, and Central Ethiopia in 2023.
Methods
A case–control investigation was carried out in households in Shashogo District from August 8, 2023, to December 10, 2023. Ten Kebeles were chosen randomly from a total of 34 Kebeles in the district. A total of 579 households (193 cases and 386 controls) were included in the study. The data were gathered with pretested and structured questionnaires in digital form with a smartphone. The data were analyzed with SPSS. Independent t tests and regression models were used to determine predictors of basic sanitation services.
Results
The mean (±SD) age of the study participants was 38.2 (±8.9) years. After controlling for confounders in the multivariate analysis, the adoption of improved latrine services among households was found to be associated with greater average monthly income (AOR = 1.841, 95% CI (1.043, 3.251)), the study respondents who had access to the necessary materials for latrine construction/upgrade were approximately 3.5 times more likely to adopt improved latrine services among households with (AOR = 3.477 (95% CI = 1.314, 9.202) than among those who lacked access to the necessary materials for latrine construction, the study respondents who had training in sanitation and hygiene (AOR = 4.744, 95% CI (2.984, 7.542)) and who had sufficient knowledge about the adoption of improved latrine services (AOR = 2.020, 95% CI (1.125, 3.628)) were found to be determinants of the adoption of improved latrine services among households.
Conclusion
This study revealed that economics, knowledge, attitudes and practices, infrastructure, and culture were identified as determinants of the adoption of improved latrines in the study area. Poor sanitation significantly impacts economic, social, environmental and many other direct and indirect impacts on the well-being of citizens. Therefore, policies on sanitation and contextual initiatives and focused actions are needed by stakeholders and policy implementers to improve knowledge gaps, access to necessary materials and the income capacity of those lagging to adopt services.
... Buckley et al. [53] formulated a general theory of the VIP pit sludge stabilisation, where, in line with other authors, they stated that anaerobic digestion is the primary sludge stabilisation process [19,20,58]. During this process, cellulose and other biopolymers can be hydrolysed into monosaccharides, which are then converted into volatile fatty acids [20,59]. ...
The current paper provides a review and meta-analysis of the practical implications of disaster risk management related to the ventilated improved latrines in South Africa. This technology is evaluated through its legacy and novel challenges of disaster risk reduction. In the current article, the methodology adopted was a literature review and meta-analyses. The results indicate that the in-situ treatment and breakdown of faecal sludge in the ventilated improved pit latrines is not always taking place and that anaerobic digestion might not always be feasible. New strategies are proposed to manage the sanitation-related risks in South Africa by specifying more exact dimensions for the newly built ventilated improved pit latrines by suggesting the use of novel sanitation additives such as fly ash to enhance on-site and in situ treatment, as well as ex situ treatment of the pit latrine faecal sludge. Regular maintenance can lead to prevention of the dysfunctional character of the ventilated improved pit latrines as a functional sanitation technology and a user-friendly hygiene barrier to the spread of sanitation/WASH-related epidemics or infectious diseases. The implementation of the novel strategies should be enhanced by the application of the (Environ-mental) Technology Assessment in sanitation service delivery in South Africa.
... A toilet or another type of pedestal may be fitted over the hole and a structure may be built for privacy (Flores, 2010). Together, DP and wet pits (discussed later) are currently used by 1.77 thousand million people (Reid et al., 2014) In DP, urine and water percolate into the soil through the bottom and side walls, while aerobic degradation occurs at the surface (Buckley et al., 2008), and anaerobic below the surface (Chaggu, 2004). Pits can be either single -for up to 20 users, or communal -for more users (Hansch, 2003). ...
This thesis presents results from studies on vermifiltration as a nature based solution for small decentralized WWTP. The purpose of the research was to support the leveraging of technical activities of a private company, which supported the study both materially and with dedication time.
... Most nuisance homestead mosquitoes (e.g., Anopheles and Culex sp.), utilise these pit latrine as "hotspots" for successful propagation [58] and further leverage other human-health complications (see discussions in Nakagiri et al. [57]. Given this scenario, modified mosquito proofing structures that limit mosquito entry into the pit latrines and minimise potential breeding may be better explored [59][60][61]. Similarly, drainage systems contribute significantly as a habitat for mosquito species providing diverse nutrient inputs to developing juveniles [62]. ...
Mosquitoes account for a significant burden of morbidity and mortality globally. Despite evidence of (1) imminent anthropogenic climate and environmental changes, (2) vector-pathogen spatio-temporal dynamics and (3) emerging and re-emerging mosquito borne infections, public knowledge on mosquito bio-ecology remain scant. In particular, knowledge, attitude and practices (KAPs) on mosquitoes are often neglected despite otherwise expensive remedial efforts against consequent infections and other indirect effects associated with disease burden. To gather baseline KAPs that identify gaps for optimising vector-borne disease control, we surveyed communities across endemic and non-endemic malaria sub-districts (Botswana). The study revealed limited knowledge of mosquitoes and their infections uniformly across endemic and non-endemic areas. In addition, a significant proportion of respondents were concerned about mosquito burdens, although their level of personal, indoor and environmental protection practices varied significantly across sub-districts. Given the limited knowledge displayed by the communities, this study facilitates bridging KAP gaps to minimise disease burdens by strengthening public education. Furthermore, it provides a baseline for future studies in mosquito bio-ecology and desirable control practices across differential spheres of the rural-urban lifestyle, with implications for enhanced livelihoods as a consequence of improved public health.
... Furthermore, human bio-waste is one of the biogas sources [8], according to Emetere and Pindar [50] the biogas productions in pit latrine is higher than in water closet (WC) due to the anaerobic and aerobic decomposition processes; solid excreta decomposition into pieces by water dissolution [8]. These processes especially the anaerobic process considered as pit latrine other filling factors [9,48,51] because gases are released to the atmosphere, and microbial and minerals compound are drained into the ground [8] thereby, reducing the significant volume of pit latrine [40,[9][10][52][53]. Therefore, determining a pit hole size depends on pit hole content and biogas harvesting. ...
The pit latrine developed in the early 20th century to control the outbreak of infection and pollution because of improper human excreta disposal. Pit latrine continues to develop to satisfy the users need for over a millennium. Although a large proportion of Northern Nigerian population practice open defecation, an estimated 70million Northerners rely on pit latrines to defecate. Studies shows the moistures discharged by pit latrine contaminate the groundwater or water sources. Based on quantitative vulnerability, the pit hole microbial and chemical discharges may pollute the water sources of about 48.5million Northerners, thereby necessitate the development of ecological friendly pit hole. Two chambers eco-friendly and costless pit hole is developed using fixed and random effect modelling with new lining techniques described as a minimum requirement standard for Northern Nigeria. Study recommended further studies on the possibility of generating electricity using human excreta biogas in Nigeria.
... The result obtained indicates that inflows of water into the pit latrine affect the sludge accumulation, thus, increasing the pit latrine filling rate. Pit latrine anaerobic and aerobic decomposition processes also other factors contributing to pit latrine filling especially anaerobic processes [33], [61], [64]. During this process, the excreta will be broken down into a firmly fixed product [37] with releasing gas into the atmosphere and mineral compound and microbial drained into the ground. ...
An estimated 69.5 million people in Northern Nigeria rely on pit latrine to defecate due to the lack of proper excreta disposal system in the region. However, many studies extensible indicates the environment and environmental resources contamination with pit latrines. It is the intent of this study to explore the numerous design features of pit latrines and which type needed to improve, thus, set a guideline on minimum pit latrine design standard. The studies on pit latrine design and structural characteristics were systematically reviewed including their evolution and improvement over a millennium, environment and environmental contamination especially groundwater and the study further assessed the extent at which the Northern Nigeria lives are at stake and knowledge gaps were found. The study found no original research on design or materials to prevent groundwater contamination despite the rises in groundwater levels due to climate change that is limiting the vertical separation distance between groundwater levels and pit latrines. Moreover, harvesting long noted greenhouse gases and additional 198 detected volatile gases emanated by pit latrine are inhabited limited data. This indicates that the concurrent pit latrine designs are less-effective in mitigating environmental and environmental resources contamination. Future pit latrine improvement or modification should focus on an integral model approach to developed a well improved and sustainable pit latrine.
... In DP, urine and water percolate into the soil through the bottom and side walls, while aerobic degradation occurs at the surface (Buckley et al. 2008), and anaerobic below the surface (Chaggu 2004). Pits can be either single-for up to 20 users, or communal-for more users (Hansch 2003). ...
This paper reviews decentralized sanitation technologies comparing dry and wet solutions currently available, discussing their operational requirements, applicability, effluent output quality, efficiencies, environmental impacts, costs, challenges, as well as their advantages and implementation difficulties. Sanitation technologies vary from conventional centralized systems, typically used on urban areas, to decentralized systems, more common in sparse dwellings and small communities of rural areas. Compared with centralized sanitation, decentralized sanitation is being progressively considered as more sustainable solution. Most do not require energy or expensive or sophisticated operation, being easy to adapt to different geographic contexts. A general lack of consistent regulatory control over most dry rudimentary systems and primary treatment systems may compromise water quality and human health. In the future, a mix of new policies and accurate accounting of the location, performance, and degree of failure of such systems should be performed. However, forcing users and communities to face the capital, operational, or repairing costs may be challenging. Since many of the discussed technologies may be important sources of contamination with nutrients, pathogens and toxic chemicals, new opportunities are still open, which include the conversion of dry rudimentary systems into dry controlled systems.
... Ammonium carbonate, (NH 4 ) 2 CO 3 , was used as a nitrogen source, as it has a similar composition to urea (Procházka et al. 2012). The range of concentrations tested was from 1.5 to 10 g N-(NH 4 ) 2 CO 3 / L (1.5, 3, 5, 7.5 and 10) representative of the range of concentrations likely to be found in pit latrines (Chaggu 2009, Zuma et al. 2015. ...
L'assainissement autonome (non raccordés à un système d'égout) est largement répandu dans les pays à faible revenu. Selon les estimations, 2.7 milliards de personnes seraient desservies principalement par des technologies d'assainissement individuelles, dont près de la moitié seraient situées en zones urbaines des pays en voie de développement (WWAP 2017). Or, l'ampleur de la couverture des installations sanitaires autonomes commence à poser de nombreux problèmes et défis techniques aux municipalités des régions concernées. En effet, l'augmentation croissante des fosses devant être vidangées, couplé aux manques d'organisation et de ressources, et à l'absence de connaissances précises sur les caractéristiques et les quantités de boues fécales générées, ne permettent pas actuellement d'assurer une vidange sécuritaire et de planifier la gestion efficace des boues fécales dans ces endroits. On estime ainsi que 74 % des fosses des installations sanitaires autonomes seront vidangées de façon non sécuritaire par année, c'est-à-dire que les boues fécales retirées seront déversées dans les cours d'eau ou terrains environnants sans traitement. Ainsi, dans la perspective d'organiser la gestion des boues fécales dans le contexte des pays en voie de développement, il conviendrait d'améliorer les connaissances sur les taux de remplissage des latrines à fosse, ainsi que sur les données de caractérisation des boues fécales. L'objectif général de cette thèse est d'améliorer la gestion des boues fécales dans le contexte des pays en développement. Pour ce faire, une série d'expérimentations a été réalisée, s'attardant à des problématiques précises de caractérisation ou de quantification des boues fécales. De façon plus précise, la première étude (CHAPITRE 4) visait la modélisation du taux d'accumulation des boues fécales en utilisant une régression linéaire multiple. Les résultats obtenus revoient un modèle impliquant les valeurs du volume des fosses et de l'âge des latrines comme principale variables indépendantes. La valeur du coefficient de détermination (r 2) qui a été obtenue est de r 2 = 0.41. Ceci qui est légèrement supérieure à la valeur obtenue à l'aide du modèle de bilan de masse développé par Brouckaert et al. (2013), pour lequel seulement 50% des latrines étaient à moins de 40% d'erreurs. Par la suite, des travaux visant la caractérisation de l'effet inhibitif de l'azote ammoniacal sur la digestion anaérobie des boues fécales au sein des fosses ont été réalisés (CHAPITRE 5). L'objectif était de valider l'hypothèse selon laquelle les fortes concentrations en azote au sein des fosses (causées par la présence d'urine) influenceraient les mécanismes de biodégradation, et conséquemment les taux d'accumulation. La méthodologie développée à d'abords été testée et validée avec des boues de digesteur anaérobie (provenant d'un réacteur complètement mélangé). Par ailleurs, le protocole développé n'a pas mené à des résultats concluants en utilisant des boues fécales. Effectivement, bien que plusieurs tests d'activité méthanogène spécifique (specific methanogenic activity-SMA) aient été réalisées (en changeant le ratio inoculum (boues)/substrat (acétate), et la durée), aucun des tests exécutés n'a démontré une production de méthane. À la lumière des résultats précédents (CHAPITRE 5), des travaux supplémentaires ont été réalisés visant à caractériser l'activité microbienne des boues fécales et de la matière fécale fraîche en termes des populations spécifiques à la digestion anaérobie (e.g. bactéries hydrolytiques et fermentatives, et méthanogènes méthylotrophes, acétoclastiques ou hydrogénotrophes) (CHAPITRE 6). Pour ce faire, la méthodologie utilisée consistait à mesurer la production de gaz (comme indicateur de l'activité microbienne) des échantillons de boues mélangés avec différents substrats spécifiques (e.i. acétate, méthanol, formate, glucose). Les résultats issus de cette étude ont démontré que l'utilisation des substrats de formate et de glucose présente l'activité microbienne la plus élevée lorsque mélangés avec une solution de matière fécale fraîche (soit de 112.17 et de 76.41 ml gaz/ g SV, pour le formate et le glucose, respectivement). Alors que l'utilisation des substrats de glucose et de méthanol ont résulté à l'activité la plus élevée avec des solutions de boues fécales plus âgées (soit de 129.15 et de 85.42 ml gaz/ g SV, pour le méthanol et le glucose, respectivement). Par ailleurs, une absence de l'activité méthanogène a été observé IV en utilisant de l'acétate comme substrat pour les deux types de boues. Ces résultats concordent avec la littérature, où des tests de séquençages d'ADN n'ont pas mené à l'identification des archaea méthanogènes acétoclasitques au sein d'échantillons de boues fécales issues de latrines à fosses (Byrne 2016, Torondel 2017). Les résultats issus de cette étude remettent donc en perspective la présence d'une digestion anaérobie acétoclastique au sein des fosses, hypothèse qui est largement présumée dans de nombreux guides de conception des latrines à fosses conventionnelles. Finalement la dernière étude constituait une étude préliminaire sur la caractérisation des propriétés de séchage de la matière fécale fraîche (CHAPITRE 7). Plus particulièrement par la détermination et par la modélisation des isothermes de sorption. Cette étude s'inscrit dans le cadre actuel où les techniques de séchage pour le transport efficient des boues gagnent en popularité, alors qu'un manque de données sur les propriétés des boues persiste. Ainsi, les résultats obtenus démontrent que les isothermes de sorption tendent à suivre une forme sigmoïde, laquelle est caractérisée par deux points d'inflexion de surface et une augmentation rapide de la teneur en eau à des valeurs d'humidité relative supérieures à 75 % HR. D'une première part, ceci signifie que la teneur en eau de la matière fécale semblerait être plus facile à extraire jusqu'à une valeur d'environ 1 à 1.5g H 2 O/g d'échantillon-base humide. D'autre part, le modèle de Guggenheim-Anderson-de Boer (GAB) sembleraient être le plus approprié pour décrire les courbes d'isothermes, avec une estimation acceptable (Pr (>|t| > 0.05).
... Almost similar findings were reported in Dar es salaam that the cost of emptying was about $35 whereas constructing a new facility would be up-to 5 times higher [30]. Therefore, the cost-benefit of emptying contents is higher than the construction of new facilities [31,32]. However, the scenarios within the study areas show that upon fill-up, pit latrines were either abandoned or decommissioned. ...
Abstract
Background: Pit latrine operational management and sludge accumulation rate, presents a challenging sanitation
problem in low-income urban settlements. However, these challenges have been under-researched. This study was
carried out between December 2014 and September 2015 in Nakuru, Kenya. Its objectives were to determine pit
latrine management activities and content accumulation rates.
Methods: A longitudinal design was used to study 100 households and their respective pit latrines. Sludge
accumulation in 73 pit latrines was monitored for 10 months using a digital laser range-finder. Data analysis included
normality testing and descriptive statistics. Differences in fill up across and within the study areas were analysed using
one-way analysis of variance and the Fisher’s Exact Test used to determine areas with significant differences.
Results: Sixty-one percent of the pit latrines were used as solid waste disposal points while 45% of the respondents
had no hygiene awareness. The annual fill-up rate and individual sludge contribution were 0.87 ± 0.20m3 and 41.82 l
respectively. The sludge accumulation rates across the study areas had statistically significant mean differences (p <0.05).
Conclusion: Operational management and design affect the fill-up rates and post fill-up management operations. This
study argues for a need to link information and awareness to users, construction artisans, property owners and local
authorities on appropriate vault volumes and management practices. Linking the variables would ensure efficient
sanitation service delivery and public health protection.
Keywords: Shared pit latrines, Basic sanitation, Faecal sludge, Developing country
... In principle, the pit latrines receive waste cumulatively and thus they act as a batch-fed system with a slow accumulation of solids in the pit. Chaggu [13] proposed that pits share many common characteristics with anaerobic reactors or digesters that have generally four key biological and chemical stages of anaerobic digestion i.e. i) hydrolysis, ii) acidogenesis, iii) acetogenesis, and iv) methanogenesis. In the first stage complex long-chain macromolecules are hydrolyzed to short-chain compounds. ...
In the next one or two decades, the largest rates of urbanization will occur in the smaller urban centers [1]. This will greatly impact wastewater production and the potential for both decentralized treatment and use. About two third of the world's population have access to improved sanitation. By 2030, global demand for energy and water is expected to grow by 40% and 50%, respectively [1]. Most of this growth will be in cities, which will require new approaches to wastewater management. On average, high-income countries treat about 70% of the wastewater they generate, while that ratio drops to 38% in upper middle-income countries and to 28% in lower middle-income countries. In low-income countries, only 8% of industrial and municipal wastewater undergoes treatment of any kind [2]. The above estimates support the often-cited approximation that, globally, it is likely that over 80% of wastewater is released to the environment without adequate treatment. Abstract A comprehensive review is presented on sewage collection, treatment and sludge formation, keeping in mind the current interest of the scientific community working on various aspect of clean environment, waste management and disposal in an environmentally friendly way. The emphasis of the review is on sewage and sewage sludge which is an endless commodity: the management of which is one of the biggest challenges for United Arab Emirates, the Gulf Cooperation Council and other developing countries relying particularly on agriculture. With the rapidly population growth the sewage waste is likely to be increased and thus procedures are to be well understood to manage this waste to a resource. The review presents historical perspective from many countries where such practice was initiated. The areas such as separation and disposal of sewage sludge, sewage treatment procedures, primary, secondary and tertiary treatments are presented as well as removal of phosphorous, nitrogen, pathogens and metals have been included.
... Furthermore, governmental initiatives, intended to support bioenergy implementation, are not coordinated and, thus, largely inefficient [ibid.]. With respect to sanitation, [58] also criticizes a strong lack of legislation in the sector of non-sewer sanitation service in TZ. ...
To reduce the consumption of firewood for cooking and to realise recycling-driven soil fertility management, three projects in Northwest Tanzania aim to provide the local smallholder community with cooking and sanitation alternatives. The present study proposes an integrated approach to assess the sustainability of the small-scale cooking and sanitation technologies. Based on the multi-criteria decision support approach (MC(D)A), we developed a decision-specific, locally adapted, and participatory assessment tool: the Multi-Criteria Technology Assessment (MCTA). Pre-testing of the tailored tool was set up with representatives of Tanzanian and German partners of case study projects. From a methodological perspective, we conclude that the MCTA uses a set of relevant criteria to realise a transparent and replicable computational Excel-tool. The combination of MC(D)A for structuring the assessment with analytical methods, such as Material Flow Analysis, for describing the performance of alternatives is a promising path for designing integrated approaches to sustainability assessments of technologies. Pre-testing of the tool served as a proof-of-concept for the general design of the method. Future applications and adjustments of the MCTA require the inclusion of end-users, a reasonable and participatory reduction of criteria, and an increase of feedback loops and group discussions between participants and the facilitator to support a common learning about the technologies and thorough understanding of the perspectives of participants.
... It provides organic waste treatment by avoiding volatile organic compounds emissions, stabilization of organic matter, build-up of an effluent with good fertilizing qualities in addition to energy recovery through methane build-up (Avery et al., 2014;Fonoll et al., 2015;Nallathambi Gunaseelan, 1997;Romero-Güiza et al., 2014). However, studies have reported unsatisfactory pathogen inactivation in AD (Chaggu, 2004;Dudley et al., 1980;Foliguet and Doncoeur, 1972;Leclerc and Brouzes, 1973;McKinney et al., 1958;Pramer et al., 1950). Thus, sludge produced requires a post-treatment step, which can be expensive, time consuming, or may create pathways for disease transmission. ...
This study examined the potential of Escherichia coli (E. coli) and Ascaris lumbricoides (A. lumbricoides) eggs inactivation in faecal matter coming from urine diverting dehydrating toilets (UDDT-F) by applying high concentrations of volatile fatty acids (VFAs) during anaerobic stabilization. The impact of individual VFAs on E. coli and A. lumbricoides eggs inactivation in UDDT-F was assessed by applying various concentrations of store-bought acetate, propionate and butyrate. High VFA concentrations were also obtained by performing co-digestion of UDDT-F with organic market waste (OMW) using various mixing ratios. All experiments were performed under anaerobic conditions in laboratory scale batch assays at 35±1 °C. A correlation was observed between E. coli log inactivation and VFA concentration. Store bought VFA spiked UDDT-F substrates achieved E. coli inactivation up to 4.7 log units/day compared to UDDT-F control sample that achieved 0.6 log units/day. In co-digesting UDDT-F and organic market waste (OMW), a ND-VFA concentration of 4800-6000 mg/L was needed to achieve E. coli log inactivation to below detectable levels and complete A. lumbricoides egg inactivation in less than four days. E. coli and A. lumbricoides egg inactivation was found to be related to the concentration of non-dissociated VFA (ND-VFA), increasing with an increase in the OMW fraction in the feed substrate. Highest ND-VFA concentration of 6500 mg/L was obtained at a UDDT-F:OMW ratio 1:1, below which there was a decline, attributed to product inhibition of acidogenic bacteria. Results of our present research showed the potential for E. coli and A. lumbricoides inactivation from UDDT-F up to WHO standards by allowing VFA build-up during anaerobic stabilization of faecal matter.
... Municipal WWTPs are not designed for treatment of sludge from OSS facilities because of the high organic load and solids in the FS. However, with co-treatment, the facilities can treat the FS under close monitoring (Straus et al., 2000;Chaggu, 2004). Problems and technical difficulties may arise in treating FS in WWTPs but there are guidelines on using the system to treat FS. ...
On-site sanitation facilities, mostly pit latrines are the main points of human excreta disposal in peri-urban low-income settlements in Kenya. Collection, treatment and final disposal of pit latrine faecal sludge, pose a significant management problem and present public health risks. The choice of appropriate faecal sludge treatment technology depends on precise region based data on the sludge characteristics that are often unavailable. The study analysed physiochemical characteristics of faecal sludge sampled at different depths of pit latrines. Twenty-four samples were collected from six pit latrines along the depth strata at 1-m intervals from the surface to 3 m depth. Samples were analysed for chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia, total nitrogen and total phosphorus. The mean COD: BOD ratio was 1:5 with a concentration of 112800 and 24600 mg/L, respectively. Concentrations for all parameters were variable and higher in comparison with properties reported in literature. Upper layers had higher concentrations than lower depths. The concentrations of the sludge were 10-100 higher than acceptable limits for in-fluent sludge into municipal wastewater treatment plants. These results show that disposal of pit latrine faecal sludge into the wastewater treatment plants without co-treatment overload the system since treatment plants in use currently have not been designed to handle pit latrine sludge. The properties of faecal sludge analysed indicate that the wastewater treatment plants may not be capable of treating faecal sludge unless co treatment mechanisms are applied. Therefore, influent faecal sludge must be maintained within allowable concentrations; otherwise, the effluents may lead to significant environmental pollution impacts.
Key words: On-site sanitation, depth strata, faecal sludge disposal, low-income settlements.
... Lower hydrogen production in this study can also be attributed to the ammonia present in brown water. Chaggu (2004), reported the ammonia concentration in brown water to be in range of 2912-5852 mg NH 4 /l and average of 4000 mg NH 4 /l. Increment of ammonia concentration in H 2 fermentation process leads to decrement in H 2 concentration. ...
Two-stage anaerobic digestion system consisting of two continuously stirred tank reactors (CSTRs) operating at mesophillic conditions (37 °C) were studied. The aim of this study is to determine optimum Hydraulic Retention Time (HRT) of the two-stage anaerobic digester system for hydrogen and methane production. This paper also discusses the effect of OLR with change in HRT on the system. Four different HRTs of 48, 24, 12, 8 h were monitored for acidogenic reactor, which provided OLR of 17.7, 34.8, 70.8, 106 g VS/L·d respectively. Two HRTs of 15 days and 20 days were studied with OLR of 1.24 and 1.76 g VS/L·d respectively in methanogenic reactor. Hydrogen production at higher OLR and shorter HRT seemed favorable 106 g VS/L·d (8 h) in acidogenic reactor system. In methanogenic reactor system HRT of 20 day with OLR of 1.24 g VS/L·d was found optimum in terms of methane production and organic removal. The result of this study illustrated the optimum HRT of 8 h and 20 days in acidogenic stage and methanogenic stage for maximum hydrogen and methane production.
... Domestic wastewater comprises of blackwater (from toilets) and greywater (from bathroom, laundry and kitchen) (Lens et al., 2001). A number of studies have attempted to address the problems associated with blackwater (Lens et al., 2001;Chaggu, 2004). However, limited attention has been given to greywater, which constitutes about 50 to 80% of the wastewater generated by households (Boghos, 2004). ...
Lake Victoria has a total surface area of 68,870 km2 and a total
catchment area of 180,950 km2. The lake water is shared by
Kenya, Tanzania and Uganda but the lake basin covers parts
of Kenya (21.5%), Tanzania (44%), Uganda (15.9%), Rwanda
(11.4%) and Burundi (7.2%). The strategic location of the lake
and the geographical distribution of the basin amongst the five
Partner States provide a strong reason for cooperation among the
states. Lake Victoria Research Initiative (VicRes) contributes to
the achievement of the cooperation through collaborative research
activities that address the challenges of development, livelihoods
and natural resources management.
VicRes is a regional research programme of the Inter University
Council for East Africa funded by the Swedish Government
through the Swedish International Development Agency (Sida)
since 2002. The programme’s core activity is to fund research in
the East African region as part of the Lake Victoria Development
Programme (LVDP), which focuses on environmental restoration
and improvement of the livelihoods of people in the Lake Victoria
Basin (LVB).
Activities of the Initiative cover six broad thematic areas namely,
Fisheries and Aquaculture, Ethnobotany and Health, Indigenous
and Local Knowledge, Land Use Options, Natural Resources
Management and Planning, and Pollution and Heavy Metals. These
thematic areas are interrelated because the activities that cause
pollution of Lake Victoria water and the basin are attributed to land
use, natural resources exploitation, fishing and many others.
These proceedings feature papers presented at the Pollution and
Heavy Metals Cluster workshop held in April 2009 in Bujumbura,
Burundi. The papers were subjected to review and edited to ensure
the quality of scientific content and technical presentation.
... Pit latrine additives used to reduce pit contents, odor or insect problems have been noted in research, but little research exists on the make-up of the additives or the prevalence of their use . The volume of water added to the pit can be large if water is used for anal cleansing or flushing in the case of pour flush latrines, or if there is a habit of bathing in the same place as the pit latrine (Chaggu 2003). Depending on the construction of the latrine, water may also enter the pit after a rain event. ...
... Matter starts to decompose as soon as it is deposited in the pit. Studies have depicted that the process of decomposition in pit latrines is largely anaerobic although aerobic degradation processes may occur [18,62,66]. During decomposition, the degradable fraction of faecal matter will break down into a more stable nonodorous product. ...
BackgroundA pit latrine is the most basic form of improved sanitation which is currently used by a number of people around the globe. In spite of the wide spread use, known successes and advantages associated with pit latrines, they have received little attention in form of research and development. This review focuses on the usage and performance (filling, smell and insect nuisance) of pit latrines in urban areas of sub-Saharan Africa (SSA) and proposes approaches for their improvements and sustainability. Methods
Current pit latrine usage within urban SSA was calculated from Joint Monitoring Programme (JMP) water and sanitation country-files. We conducted a literature search and review of documents on pit latrine usage, filling, smell and insect nuisances in urban areas of SSA. Findings of the review are presented and discussed in this paper. Results and DiscussionPit latrines are in use by more than half the urban population in SSA and especially among low income earners. An additional 36 million people in urban areas of SSA have adopted the pit latrine since 2007. However, their performance is unsatisfactory. Available literature shows that contributions have been made to address shortfalls related to pit latrine use in terms of science and technological innovations. However, further research is still needed. Conclusion
Any technology and process management innovations to pit latrines should involve scientifically guided approaches. In addition, development, dissemination and enforcement of minimum pit latrine design standards are important while the importance of hygienic latrines should also be emphasized.
... At an organic loading rate (OLR) of 4.1 kgCOD·m −3 ·d −1 and an HRT of 4.1 d, this system achieved a mean removal efficiency of 70%. Chaggu (2004) used an accumulation system (IMPLWUS = improved pit latrine without urine separation) for the anaerobic storage and treatment of faeces, urine and small amounts of cleansing water under tropical ambient temperatures (25-30°C). The filling period was 380 d. ...
... Unfortunately, tap water supply system in the city is inefficient and unsafe due to outdated pipe system and/or lack of water decontamination process [2]. This significantly has attributed to constant waterborne disease outbreaks in Dar es Salaam [3], which certainly have led to proliferation of bottled water business. In most urban areas in Tanzania, large proportion of the people depend on bottled/packaged water owing to its perceived safety as compared to water from public pipe systems [4]. ...
Background: Dar es Salaam City has over 10 million habitants, who are constantly circumvented by waterborne diseases. The city experiences humid and hot weather throughout a year, which lead to high consumption of bottled drinking water because of being perceived as safer than tap or well water. Waterborne disease outbreaks still create havoc among the city habitants. This study determines heterotrophic plate count (HPC) values in bottled water and performs antimicrobial resistance tests on isolated microorganisms. Methods: A cross-sectional study was conducted. Fifty-four samples of bottled water were randomly purchased from shops, supermarkets and street vendors. HPC values were determined and microbial contaminants identified. The disk diffusion method was employed for testing antimicrobial resistance of microbial contaminants against four widely used antibiotics. Results: HPC values were variable (4.7 x102 to 7.0 x105 cfu/ml). Majority (86.7%) of analyzed samples revealed high HPC values. Four bacterial species were isolated and identified from 47 samples. Predominant bacterial contaminants were Brevundimonas vesicularis (54.5%), while Pseudomonas thomasii was only isolated from one brand A sample. Brand E samples had the highest HPC values (2.2 x 104 to 2.16 x105 cfu/ml) while F samples were free from microbial contaminants. A total of 21 (46.7%) bacterial isolates were resistant to commonly used antibiotics namely ciprofloxacin, ampicillin, cotrimoxazole and chloramphenicol. Conclusion: Of 54 analyzed bottled water samples, 47 had high HPC values. High rates of antibacterial resistance was exerted against ciprofloxacin (68.2%) and ampicillin (56%). This calls for responsible authorities to impose more stringent measures on in-process quality control among bottled water producers and indefatigably conduct postproduction surveillance to avert the endemic water-borne outbreaks resulting from consumption of such products.
... Taking a simplistic approach to the problem in the absence of local information, the system is assumed to receive 520 g per person per day wet feces in an African area. 4 Assuming 85% moisture content (wet base) for the feces, 26 moisture input is calculated to be 0.44 l per person per day. Expecting this amount of input allows approximately 146 people to utilize the on-site sanitation system daily. ...
One of the major challenges of biowaste management is efficient removal of water from sludges or biosolids, which are generally quite hydrophilic. Also, any water that is removed must be re-treated to remove contaminants that do not partition completely into the solids fraction. To address these issues, a membrane distillation process was adapted for drying and stabilizing sludges. Hydrophobic membranes used in this process are nonwetting, with pore spaces that allow only vapor transport. Water vapor can be expelled because of a moderate temperature gradient. Other constituents, including both particulate and dissolved matter, are retained. The permeate purity, therefore, is expected to be high. This chapter presents data showing usable rates of moisture transfer with modest temperature gradients. In the modeling effort to simulate the moisture transfer from the system, effectiveness and validity of three candidate models were examined: a diffusion equation with flux-type boundary conditions, a two-period model, and a stagnant film model. Among these, the stagnant film model is considered a fundamental modeling framework, because it incorporates all the factors controlling drying intensity and pattern, and it successfully predicts the mass transfer across the membrane. The prediction is used to estimate the waste loading that a membrane-enclosed pit latrine can handle daily.
... The World Health Organization recommends a pathogen reduction of 8-9 log units in excreta before being used as a soil conditioner for agricultural purposes [8]. Available literature [9][10][11][12] indicate that pathogen destruction in human excreta can be achieved by a host of technologies including ammonia treatment, irradiation, dewatering, mesophilic or thermophilic anaerobic digestion, membrane filtration and a combination of these methods. The efficiency of pathogen removal for these technologies has been well documented [12][13][14][15][16][17]. ...
Wood ash has been widely used as an additive for excreta from dry compost toilets to sanitize it for reuse. However, there is dearth of quantitative information about its efficiency in sanitizing partially digested sludge from wet onsite sanitation systems. This paper presents findings of a series of two experimental studies to assess optimum wood ash dosages required to raise the pH of partially digested fecal sludge to sanitizing levels (pH > 11) in a tropical climate. The study monitored the variation of pH of the sludge containing between 0 (control) and 180 g of ash per litre of sludge. Average initial pH and total solids of the sludge were 7.79 and 72 g/L respectively. Generally, the magnitude and rapidity of pH spike was correlated with the ash dosage (r = 0.988) and was statistically significant (p = 0.0015; Fcrit = 2.3157) among all dosages. Drastic increase in pH (from 7.81 to 11.60 ± 0.07) was recorded in the first 24 h for ash dosages between 140 g/L and 180 g/L, whereas dosages below 140 g/L had pH values less than 10. The difference in variation of pH between the first 24 h and the successive 24 h was statistically significant (P(T ≤ t)two-tail = 0.00; tcrit = 2.09). On the average, 97% of the overall pH increment within a 48-h monitoring period occurred in the first 24 h for the 140–180 g/L ash dosages. The optimum ash dosages are 7–15 times higher than reported lime dosages but ash provides a cheaper alternative than lime for recycling plant nutrients. Further studies on pathogen inactivation efficiency are ongoing.
... 10 11 ‐10 13 /g. Tabela 4. Valores médios da caracterização físico‐química das fezes coletadas nos sanitários segregadores (valor médio ± desvio padrão) comparados aos dados da literatura Parâmetros Esta pesquisa Del Porto (1999) Esrey et al. (2001) Chaggu et al. (2003) Jönsson et al. (2005) Kujawa e Zeeman (2006) pH 6,7 ± 0,2 ‐ ‐ ‐ ‐ ‐ Umidade, em % 75,3 ± 3,1 ‐ ‐ 66 ‐ 85 70 ‐ Sólidos Voláteis, em % 85 ± 4 ‐ ‐ 88 ‐ 97 79,4 ‐ Fósforo (gP/kg fezes) * 3,2 ± 1,1 4 5,4 8,1 ‐ 9,9 3,8 2,3 ‐ 5,4 Nitrogênio (gN/kg fezes) * 12,9 ± 7,8 13,3 10,7 10,5 ‐ 16,5 11,5 11,5 ‐ 15,4 DQO (gDQO/kg fezes) * 450 ± 141 ‐ ‐ 105 ‐ 522 288 351 ‐ 419 C org (gC org /kg fezes) * 161,5 ± 2,0 ‐ 152,8 ‐ ‐ ‐ Legenda: * Peso seco ...
The Ecological Sanitation (Ecosan) refers to the residuary waters management system focusing in a principle of recycle the water and the nutrients back to their generating source. Segregate faeces and urine, avoiding their mixture, is one of the Ecosan's basics markings. The human faeces obtained after the segregation have valuable qualities for soil improvement, however the main abstraction in this nutrients recycling is the association with enteric pathogens. The composting is the most common treatment to reach a disinfection of the faeces when the goal is its application as soil conditioner. In this sense, the objectives were characterize the excreta under a physico‐chemical and biological's view; study the optimum conditions of composting human faeces with carbonaceous addition from sawdust and confirm the quality of the final compost to application on soil. The used methodology was separated in two stages: I. faeces quali‐quantitative characterization and II. human faeces composting by application of three sawdust's proportions. The obtained result was the temperature over than 50°C and a reduction of Escherichia coli to not detectable levels.
... Kujawa-Roeleveld and Zeeman (2006) 567 Chaggu et al. (2007) 1671 Bai and Wang (2010) 38 96 Choi et al. (2004) 19.3 Fourie and Van Ryneveld (1995) 1448 354 Buckley et al. (2008) 32 50 Meinzinger and Oldenburg (2009) 46,230–78,310 Chaggu (2004) * Includes toilet paper. values (Table 6). ...
The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh faeces and urine was collected from the medical literature as well as the treatability sector. The data were summarised and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators and chemical processes was then assessed. Results showed that the median faecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Faecal output in healthy individuals was 1.20 defecations per 24 hour period and the main factor affecting faecal mass was the fibre intake of the population. Faecal wet mass values were increased by a factor of 2 in low income countries (high fibre intakes) in comparison to values found in high income countries (low fibre intakes). Faeces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25-54% of dry solids) of the organic fraction of the faeces. Undigested carbohydrate, fibre, protein and fat comprise the remainder and the amounts depend on diet and diarrhoea prevalence in the population. The inorganic component of the faeces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 litres/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions as well as water, salt and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the faecal and urine composition and these variables should always be considered if the generation rate, physical and chemical composition of faeces and urine is to be accurately predicted.
... Nitrate is generally encountered in water impacted by intensive livestock production, fertiliser application, or onsite excreta disposal facilities, especially pit latrines and septic tank systems. Pit latrines and septic tank effluents are probably the important sources of nitrate in groundwater since over 85% of the Dar es Salaam residents use these systems (Mato, 2002;Chaggu, 2004). Nitrate concentration levels in groundwater in some places have been reported to exceed the Tanzanian Drinking Water Quality Standards (10 mg/l) (Mato, 2002). ...
Samples of various brands of bottled water sold in Dar es Salaam, Tanzania were analyzed for physicochemical water quality parameters. For comparison purposes, tap water was similarly examined. The results showed great variations in physico-chemical quality of bottled water, with some samples exceeding the Tanzania Drinking Water Quality Standards for nitrate, pH and lead. Significant discrepancies were observed between the labelled and measured values for all the investigated parameters except for pH. Meanconcentration values of TDS and nitrate in tap water were found to be significantly lower than those of bottled water. On the whole, this study suggests that bottled water offers little advantage over tap water except in terms of turbidity and colour.
... Other differences include a comparatively low pathogen load and a 90% less nitrogen in greywater as compared to blackwater [3]. Many studies focusing on problems associated with blackwater have been carried out [2,4]. However, limited attention has been given to greywater, which constitutes about 50 to 80 % of the wastewater generated by households [5,6]. ...
In recent years concerns over dwindling reserves of ground water and overloaded or costly sewage treatment plants has generated much interest in the reuse or recycling of greywater. Re-use of greywater offers several advantages including a reduction in the demand on potable water supplies. Despite the prevalent direct reuse of greywater, especially in water scarce areas, its quality is not well documented. This study determined the physico-chemical and microbial quality of greywater produced by households in Homa Bay town. Most of greywater generated had a higher electrical conductivity and salinity and lower concentration of dissolved oxygen. Greywater pH values varied widely but were mostly higher than that of clean water. Biological oxygen demand varied widely (410-6250 mg L -1). Total coliform (TC) counts in greywater samples ranged from 1.3 to 7.6 colony forming units (CFU)/ 100 mL while fecal coliform (FC) counts varied between 3000 and 7.4 million CFU/ 100 mL. Field observations showed that the variation in TC and FC counts resulted from differences in the level of households' personal hygiene, difference in the intensity of greywater reuse and duration of storage. Among the potentially pathogenic bacteria investigated, Salmonella was the most frequent, occurring in 31% of all the greywater samples collected. Vibrio occurred in the least number of samples (9%). The study concludes that greywater produced is most likely to be contaminated by pathogenic bacteria and should therefore be disinfected prior to reuse.
... The pit if well operated contains faeces, urine, anal cleansing material and/or anal cleansing water (8). A pit should end up with stable sludge material, at the time when it is full and have approximately zero organic fatty acid (VFA) at the time of emptying (9). However, disposal of multiple wastes into the pit results in non-homogenous properties of pit contents. ...
Analysis of samples of fresh faecal material and samples from range of pit latrines and from pit latrines within a number of locations have been analysed for organic and inorganic characteristics including total COD, moisture, total solids and inorganic solids. Assessment of the results has lead to the development of a conceptual model of biological degradation processes that occur in a pit latrine. The faecal sludge portion of pit contents may be divided into four theoretical categories: (i) the first category is sludge where readily biodegradable components are still present, wherein rapid aerobic degradation occurs. This layer is negligibly small and is not measurable in practice; (ii) the second category is made up of the top aerobic section of the pit. In this layer, aerobic degradation of hydrolysable organic material occurs at a rate limited by the aerobic hydrolysis of complex organic molecules to simpler compounds; (iii) the third layer is anaerobic due to the occlusion of oxygen by covering material. Anaerobic digestion proceeds at a significantly slower rate than in the layer above, and is controlled by the rate of anaerobic hydrolysis of complex organic molecules to simpler molecules; and (iv) in the lowest layer, no further stabilisation of organic material occurs within the remaining life of the pit contents. In this paper, qualitative and quantitative characteristics are reported for each of the layers described. Factors that affect the rates of degradation, and thus the relative sizes of each of the layers are discussed. This information is then used in a parallel paper to assess the feasibility of different routes for disposal of pit latrine contents, including disposal to sewer, wastewater treatment plant, burying and anaerobic digestion. The feasibility of each of the disposal routes depends on the inherent ability of the treatment to accept the load of solids, nitrogen and organic material in the VIP sludge, the residual biodegradability of the VIP sludge, and the health risks associated with handling the sludge Lack of basic sanitation and access to clean water supply is a major cause of diseases and infant mortality in developing countries (1). Worldwide, approximately 2.6 billion people lack improved sanitation and the largest part of this resides in Africa and Asia. Sanitation options such as ventilated improved pit latrines (VIP) are considered by the World Health Organisations as improved. Consequently, around the world, there is a drive to ensure the provision of proper sanitation and access to clean water supply. In line with this, one of the Millennium Development targets is to reduce the number of people with no access to basic sanitation by 50 %, by 2015.
Non-sewered sanitation systems (NSSS) are identified as a significant contributor of greenhouse gases (GHGs), primarily due to biological processes within the containment systems. In unsealed or unlined containment systems like pit latrines, the emissions are influenced by moisture. This work quantified the GHG emission occurring from unlined or unsealed containments prevalent in Nepal and compared it with sealed containment-like septic tanks, where the chances of groundwater (GW) inundation are low. The modeled GW data extracted from the secondary sources were validated with available national data. The emissions were quantified using the Intergovernmental Panel for Climate Change (IPCC) model for different ecological divisions and provincial divisions of Nepal. Spatial representation for the results was done using the Geographical Information System (GIS) tool. The total methane (CH4) emission occurring from the various NSSS was determined to be 2,618 Gg CO2 e per year which is almost twice the emission from the waste sector, as reported by the recent national communication submitted to the United Nations Framework Convention on Climate Change (UNFCC). Variation of the CH4 emission was found to be prominent in lowlands (Terai region) with total national emissions of 1,329.37 Gg CO2e per year. The lowland has a shallow GW table that can easily inundate the unlined containments like pit latrines thus contributing to more anaerobic conditions which may lead to higher CH4 emissions compared to containments in mid and highlands. This study concludes that the GHG emissions occurring from NSSS are substantial and addressing these emissions can help fulfil the Nationally Determined Contributions (NDCs) in the waste sector.
Pit latrines in slums areas of Uganda fill up faster than might be expected from some estimates owing to inappropriate use and failure to consider critical factors affecting sludge accumulation rates at the planning, design and construction stages. This study sought to investigate factors affecting filling rates of lined pit latrines in slum areas of Kampala with the goal of contributing to accurate planning, design, construction, emptying and overall maintenance. Fifty-five pit latrines were selected from the five divisions of Kampala city using stratified random sampling. Data collected included: number of users, frequency of emptying, years taken since last emptying, type of non-faecal materials deposited, cross-sectional dimensions of the pit, rate of sludge degradation and geo-physical factors of pit location. Methods used were: field surveys, questionnaires and key informant interviews plus on-site depth measurement. Mass loss tests to investigate the rate of sludge degradation were carried out in the laboratory at moisture content levels similar to those in pit latrines. Sludge accumulation rates were calculated using volume of sludge in the pit, number of users and time taken since last emptying. Statistical analyses included correlation and one-way ANOVA. Results revealed that number of users and type of material deposited in the pit latrines, especially non-faecal matter, had a significant (p
This study investigates a solar thermal water heating system that is effective in drying and disinfecting fecal sludge (FS) and recovering nutrients and water resources that happen to have fertility values for agricultural use. The fertilization value of the dried sludge and condensate was tested in a laboratory-scale plantation using three types of plants used as fodder for animals. Results showed average sludge temperatures reached during sludge drying and disinfection were 39.5°C and 33.9°C in dry and wet seasons, respectively. The sludge’s water content decreased from 99.32% to 5.3% and 81.57% to 5.5% in 40 and 54 days of dry and wet seasons, respectively. Pathogen reduction in the dry season was 100% for 13 days compared to 42 days in the wet season. The evaporation rate was higher in the dry season at 9.099×10−4 kg H2O/m2⋅d, compared to 6.4514×10−4 kg H2O/m2⋅d in the wet season, whereas condensation rate was higher in the wet season at 5.59×10−5 kg H2O/day compared to 4.94×10−5 kg H2O/day in the dry season. Dried sludge increased the soil porosity by 9.39% compared to 8.41% for raw FS. Also, it increased the soil permeability from 0.06302×10−6 to 5.773×10−6 cm/s, whereas raw FS decreased the soil permeability to 0.02163×10−6 cm/s. Moreover, dried sludge improved soil pH values between 7.04 and 7.39. Statistical analysis results at a 95% confidence level revealed that plants in the soil treated with dried sludge had significantly better growth characteristics than others.
The present study aims at developing an efficient bacterial consortium to biodegrade butyric acid, one of the odor-causing compounds that contribute significantly to pit latrine malodors. Six bacterial strains isolated from pit latrine fecal sludge were selected for the study. Nineteen bacterial consortia of different combinations were artificially constructed. The individual bacterial strains and bacterial consortia were compared by culturing in mineral salt medium supplemented with 1000 mg/L butyric acid as a sole carbon and energy source at pH 7, 30 °C, and 110 rpm under aerobic growth conditions. A co-culture of Serratia marcescens and Bacillus cereus was an effective bacterial consortium compared to individual component bacterial strains and other bacterial consortia, in which 1000 mg/L butyric acid was completely degraded within 16 h of incubation. A temperature of 30 °C and pH 7 were found to be optimum for the maximum degradation for both S.marcescens and B.cereus. The inoculation sizes of 2.0 and 2.5 were optimal for the maximum degradation for B.cereus and S.marcescens, respectively. The study provides insights that will be of substantial help in the development of effective biological treatment technologies for pit latrine odor to change the pit latrine user community’s and would be users’ perception of pit latrines.
Biochemical energy recovery using digestion and co-digestion of faecal matter collected from urine diverting dehydrating toilet faeces (UDDT-F) and mixed organic market waste (OMW) was studied under laboratory- and pilot-scale conditions. Laboratory-scale biochemical methane potential (BMP) tests showed an increase in methane production with an increase in OMW fraction in the feed substrate. In subsequent pilot-scale experiments, one-stage and two-stage plug flow digester were researched, applying UDDT-F:OMW ratios of 4:1 and 1:0, at about 10 and 12% total solids (TS) slurry concentrations. Comparable methane production was observed in one-stage (Ro-4:1,12%) (314 ± 15 mL CH4/g VS added) and two-stage (Ram-4:1,12%) (325 ± 12 mL CH4/g VS added) digesters, when applying 12% TS slurry concentration. However, biogas production in Ram-4:1,12% digester (571 ± 25 mL CH4/g VS added) was about 12% higher than in Ro-4:1,12%, significantly more than the slight difference in methane production, i.e. 3–4%. The former was attributed to enhanced waste solubilisation and increased CO2 dissolution, resulting from mixing the bicarbonate-rich methanogenic effluent for neutralisation purposes with the low pH (4.9) influent acquired from the pre-acidification stage. Moreover, higher process stability was observed in the first parts of the plug flow two-stage digester, characterised by lower VFA concentrations.
Digestion and co-digestion of faecal matter collected from urine diverting dehydrating toilet faeces (UDDT-F) and mixed organic market waste (OMW) was studied in single stage pilot scale mesophilic plug-flow anaerobic reactors at UDDT-F:OMW ratios 4:1 and 1:0. Escherichia coli inactivation and volatile fatty acids (VFA) build-up was monitored at sampling points located along the reactor profile. When applying UDDT-F:OMW ratio of 4:1 at 12% total solids (TS), E. coli inactivation achieved was 2.3 log times higher than that achieved in UDDT-F:OMW ratio of 1:0. In subsequent trials, a two-stage reactor was researched, applying a UDDT-F:OMW ratio of 4:1 and 10 or 12% TS slurry concentrations. Highest VFA concentrations of 16.3 ± 1.3 g/L were obtained at a pH of 4.9 in the hydrolysis/ acidogenesis reactor, applying a UDDT-F:OMW ratio of 4:1 and 12% TS, corresponding to a non-dissociated (ND)-VFA concentration of 6.9 ± 2.0 g/L. The corresponding decay rate reached a value of 1.6 per day. In the subsequent methanogenic plug-flow reactor, a decay rate of 1.1 per day was attained within the first third part of the reactor length, which declined to 0.6 per day within the last third part of the reactor length. Results show that a two-stage system is an efficient way to enhance pathogen inactivation during anaerobic digestion.
The supplements to article 'Recycling Improves Soil Fertility Management in Smallholdings in Tanzania' contain (I) supplementary material such as additional results and tables with plot data and (II) the appendix providing detailed information about the set-up of the model and equations applied.
Background: Faecal sludge (FS) represents a huge resource, which when tapped and made use properly can be of great benefit to many. However, the key to tapping this resource lies in proper characterisation, in order to make known the constituents and thereby determine the end-use.
Methods: Three sources of FS from 43 communities in the Kumasi metropolis of Ghana were characterised in terms of their total solids content, chemical oxygen demand (COD), pH, nitrogen, phosphorous and lipid contents. FS from pit latrines, public septage and private septage were analysed.
Results: On average, lipid content was found to be in the range of 8.82 – 9.66% of dry FS depending on the source of FS. Total solids were between 0.79 and 4.68%, while the COD was between 9495 and 45611mg/L. Phosphorus content was in the range of 137 – 520mg/L, while nitrogen was 649 – 4479mg/L. Most FS samples were generally alkaline in nature.
Conclusions: These results are amongst the first long-term characterization efforts for FS in terms of conventional and non-conventional characteristics, tailored towards typical treatment and novel resource recovery options, respectively.
To address the shortcomings of modern wastewater treatment, Ecological Sanitation (EcoSan) has been advocated as a sustainable approach to promote closed–loop flows of resources and nutrients from sanitation to agriculture. In this study, we discuss the rationale behind its conception and provide a state–of–the–art review on the subject. Through an exhaustive literature analysis of EcoSan systems, its historical developments and programs implemented worldwide we (i) validate the potential applicability and feasibility of decentralized, source–based sanitation and (ii) depict fundamental problems in EcoSan systems design that have stalled its adoption and proliferation. Specifically, we focus on urine diversion to demonstrate its potential to elegantly separate, collect and concentrate products that we require (nutrients) and those that we wish to regulate (pathogens and micropollutants). Since recent research efforts have been devoted to the technological recovery of nutrients from human urine, we believe that we are witnessing a paradigm shift within a paradigm shift as it represents a change in emphasis from ‘split–stream collection and reuse’ to ‘split–stream collection, resource recovery and safe reuse’. Our analysis of various nutrient recovery technologies for human urine indicates that provisioning of urine–diverting toilets tends to reduce sanitary risks; however, to contain and completely eliminate these risks continued research effort is needed to envision and implement integrated technological pathways that ensure simultaneous nutrient recovery, pathogen inactivation and reduction of pharmaceuticals and active substances.
The prolonged challenges and terrible consequences of poor sanitation, especially in developing economies, call for the exploration of new sustainable sanitation technologies. Such technologies must be: capable of effectively treating human faecal wastes without any health or environmental impacts; scalable to address rapid increases in population and urbanization; capable of meeting environmental regulations and standards for faecal management; and competitive with existing strategies. Further and importantly, despite its noxiousness and pathogenic load, the chemical composition of human faecal sludge indicates that it could be considered a potentially valuable, nutrient-rich renewable resource, rather than a problematic waste product. New approaches to faecal sludge management must consequently seek to incorporate a ‘valuable resource recovery’ approach, compatible with stringent treatment requirements.
This review intends to advance the understanding of human faecal sludge as a sustainable organic-rich resource that is typically high in moisture (up to 97 per cent), making it a suitable candidate for dielectric heating, i.e. microwave irradiation, to promote faecal treatment, while also recovering value-added products such as ammonia liquor concentrate (suitable for fertilizers) and chars (suitable for fuel) – which can provide an economic base to sustain the technology. Additionally, microwaving human faecal sludge represents a thermally effective approach that can destroy pathogens, eradicate the foul odour associated human faecal sludge, while also preventing hazardous product formations and/or emissions, aside from other benefits such as improved dewaterability and heavy metals recovery. Key technological parameters crucial for scaling the technology as a complementary solution to the challenges of onsite sanitation are also discussed.
The green coconut husk processing pilot plant, installed in Fortaleza with funds from a project Embrapa, generate about 15 m3/day of an effluent called Coconut Husk Liquor (CHL), whose chemical oxygen demand (COD) is approximately 60 g/L. To evaluate what is the best treatment process for this kind of fluid, tests were carried out based on toxicity tests (anaerobic, aerobic and fungal) to determine the ability of degradation of each type of reactor; and operation of laboratory scale reactors (upflow anaerobic sludge blanket reactor - UASB, Fungi Reactor - FR and Activated Sludge System - ASS). The results showed that LCCV causes inhibition in the metabolism of Aspergillus niger and the yeasts that exist within the medium promoted the degradation of easily degradable organic matter. During anaerobic activity tests, it seems that there was no inhibition of the methanogenic activity. The tests for Oxygen Uptake Rate showed no inhibition of metabolism of aerobic bacteria. The UASB reactor showed the highest robustness for the treatment of LCCV, but it does not promote the complete removal of organic matter (up to 80%), requiring a post-treatment. The FR can remove more than 90% of organic matter LCCV, but there are serious operational problems, indicating that the system used in this research is not the most appropriate (perhaps a modification of the biodisk system, using yeast as inoculum is a good solution). The activated sludge had a poor performance when operated with raw LCCV, but there is evidence that a combined UASB-ASS is the most efficient. Moreover, the post-treatment through a reactor with fungi (biodisk system) may allow the recovery of tannins.
Co-digestion, pretreatment and digester design are the key techniques for enhanced biogas optimization. Co-digestion dilutes the inhibitory effects of substrates, balance the micro and macronutrients, increase the organic loading with consequent higher methane yields per unit of digester volume; lastly diversify and synergize the microbial communities which play pivotal role in the methanogenesis. Pretreatment facilitates in conversion of polymers to monomers and increased accessibility of the food to microbes. Proper and accessible feed have a crucial role in the biogas enhancement. The biodegradability of any particular biomass depends on its source from which it has been derived. The biodegradability of a biomass may be affected by various factors like crystalline structure the extent of cellulosic polymers; the surface properties of biomass, the amount of lignin content, the presence of hemicellulosic materials and the strength of fibers. The present review also discussed various types of the pretreatment to remove the obstacles before feeding for biogas digesters. Various biomasses being utilized for the anaerobic digestion of biogas optimization were discussed. The current review also discussed the digester design along various operation physical conditions and the nature of feed substrates employed for biogas optimization.
This paper describes the on going pilot project of Ecological Sanitation in Tanzania, the project that has been introduced in Tanzania at the end of last year (November 2000). The project is funded by Unicef and implemented by EEPCO a National NGO based in Dar Es Salaam. Just like many African countries, unplanned settlements have kept increasing in many Tanzanian towns and Dar Es Salaam in particular there are more than ten including Majumbasita and there are no immediate means to upgrade these settlements. A substantial population is currently found residing on un-surveyed land mainly on the hillside areas of Dar Es Salaam. The City has the estimated population of 4 millions in a land of 139300 hectares. A baseline survey carried out by EEPCO in 1999 indicated that the level of sanitation service was unsatisfactory about 68% coverage including the temporally tradition toilets. Although the master plan stipulates the removal of these squatter areas, they are likely to remain in existence for many years to come, because of their political sensitivity. Many problems arise due to the poor existing infrastructures, lack of hygienic sanitation; poor disposal of waste, consistently negative balances of nutrients there is widespread processes of soil fertility decline which most of them end up into eutrophication of Msimbazi river. The problems of diarrhea and other faecal –related diseases remain highly endemic. In ability of existing sanitation systems to manage adequately the massive and still increasing volume of human excreta is the main cause for the high incidence of infectious diseases in most of our settlements. This has contributed significantly to the wide increase in ecological problems. The main reasons behind these problems are rapid population growth and an unsuitable technological response. Conventional sanitation technologies based on flush toilets, sewers, treatment and discharge cannot solve these problems in urban areas like Majumbasita where the lacking of necessary resources such as water, money and institutional capacity are existing, that is why the use of ecological sanitation has been proposed and implemented to solve these problems.