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The amount of available freshwater in most low- and middle-income countries is not sufficient to meet increasing demand. Treated municipal wastewater often becomes a significant source of irrigation water.
Wastewater is valuable and its reuse has many potential benefits: flow is reliable even where water is scarce, nutrients increase agriculture...
Citations
... CW systems are usually integrated with other treatment systems such as waste stabilization ponds (WSPs) and septic tanks, and therefore are most often used as secondary treatment systems. Effluents from these systems are used for various purposes such as agricultural irrigation and brickmaking, and as water sources for livestock (Outwater et al. 2013, Kihila et al. 2014). According to the World Health Organization (WHO) guidelines on the safe reuse of wastewater, monitoring of wastewater treatment is important to ensure that the system achieves specified standards and ultimately the health-based target. ...
Wastewater treatment is a widely used health protection measure that can be applied to control the transmission of wastewater-related infectious diseases to communities exposed to wastewater. This study determined the efficiency of three full-scale constructed wetlands (CWs) in removing pathogenic parasites and fecal coliform (FC) bacteria from wastewater. Wastewater samples were collected from three CW systems located in the Dar es Salaam and Iringa regions of Tanzania. The modified Bailenger and modified Ziehl-Neelsen stain techniques were used to detect and quantify parasites. The membrane filtration method was used to detect and quantify FC bacteria. Data were analysed using IBM SPSS version 20. Helminth (Ascaris lumbricoides, hookworm, and Taenia spp.) eggs were completely removed by two CW systems. In all the systems, the removal of protozoa ranged from 99.8% to 100%. The mean concentrations of FCs in effluents ranged from 5 to 6 log units/100 mL. Effluents of all CW systems met the recommended parasitological quality requirements of the World Health Organization for the safe reuse of wastewater. FC effluents concentrations did not meet the local discharge standards of the Tanzania Bureau of Standards. Therefore, improvement to the CWs' design, operation, and maintenance are required for the efficient removal of bacteria.
... Wastewater stabilization ponds are utilized to partially treat the effluents from industries, residential areas, and hospitals. Therefore, when effluents are released into the ecosystem, the chemical load is increased [48][49][50][51][52][53][54]. Occurrences of the active chemicals in the Tanzanian environment are presented in Table 4. ...
Active chemicals are among the contaminants of emerging concern that are rarely covered in regulatory documents in sub-Saharan Africa. These substances are neither in the list of routinely monitored substances nor in the guidelines for routine environmental monitoring activities. This has been of concern to public health officials, toxicologists, communities, and governments, hence the need for risk assessment and regulation of these substances. In this review article, the presence of active chemicals in the sub-Saharan African environment was investigated. The results indicate the availability of few studies in some countries, while in other countries no reports of active chemicals were found, hence the need for further research targeting such countries. It was further observed that mixtures of active chemicals from different therapeutic categories—such as antibiotics and analgesics—were reported. The natural environment is increasingly at risk due to the presence of these substances, their metabolites, and their transformation byproducts. These substances are characterized by persistence as a result of their non-biodegradable nature; hence, they circulate from one environmental compartment to another through the food chain, causing harm along the way. Most studies that evaluated the toxicity of these substances considered the effects of a single drug, but observations indicated the presence of drug mixtures, hence the need for further evaluation of the effects of drug–drug interactions—including synergistic and additive effects—for environmental sustainability. The presence of ACs in several environmental compartments at quantifiable quantities was discovered in this investigation, indicating the potential for ecosystem injury as a result of bioaccumulation, bioconcentration, and biomagnification through the food chain. This necessitates further research on the subject in order to ensure a healthier environment.
... In Tanzania, waste stabilization ponds (WSPs) have been used for municipal wastewater treatment for several decades [1]. Effluents from various WSP systems are used for urban agricultural activities, such as vegetable gardening in Iringa [2], and vegetable and rice paddy farming in Moshi [3] and Morogoro [4]. Using WSP effluent for irrigation was observed to benefit farmers. ...
In Tanzania, waste stabilization ponds (WSPs) are employed to treat wastewater, and effluents are used for urban agricultural activities. The use of untreated or partially treated wastewater poses risks of disease transmission, including parasitic and bacterial infections, to exposed communities. Little is known about the occurrence, concentration, and removal of parasites and fecal coliform (FC) bacteria in WSPs in Tanzania. This study evaluates the occurrence and concentration of parasites and FCs in wastewater, the efficiency of WSPs in removing parasites and FCs, and the validity of using FCs as an indicator of parasites. This was a cross-sectional study conducted between February and August 2018. Wastewater samples were collected from three WSPs located in the Morogoro, Mwanza, and Iringa regions. APHA methods were used to test physicochemical parameters. The modified Bailenger method and Ziehl–Neelsen stain were used to analyse parasites. Membrane filtration method was used to analyse FCs. Data were analysed using IBM SPSS version 20. Helminth egg removal ranged from 80.8% to 100%. Protozoan (oo)cyst removal ranged from 98.8% to 99.9%. The Mwanza WSP showed the highest FC reduction (3.8 log units (100 mL)−1). Both the parasites and FCs detected in the effluents of assessed WSPs were of higher concentrations than World Health Organization and Tanzania Bureau of Standards limits, except for helminths in the Morogoro WSP and FCs in the Mwanza WSP. FCs were significantly correlated with protozoa (p
... At global level UN-Habitat [10] estimated the incidence of diarrhoea and acute respiratory infections to be twice and six times higher respectively, for children living in the households where solid wastes are dumped at homesteads compared to children living in the households where wastes are dumped away. In Tanzania the situation is even worse because 50% of Tanzanians suffer from intestinal schistosomiasis and soil transmitted helminths resulting from haphazard solid waste dumping [11]. Sakijege et al [12] estimated the presence of total coliform in drinking water to stand at 70 and 23 counts/100 ml compared to WHO recommended rate of zero (0) coliform/100 ml (coliform free water) in the drinking water [13]. ...
In Tanzania only 40% of solid wastes in urbanized areas are collected and transported to the dumping sites. The remaining 60% are illegally disposed along road sides, sewage canals and reserved open spaces that contribute to floods and breeding of rodent vectors that eventually spread diseases such as intestinal schistosomiasis and soil transmitted helminths. Public Private Partnership (PPP) has been adopted to address Solid Waste Management (SWM) in various countries and yielded robust results. However the PPP model has not been effective for Tanzania since its initiation in 1995. Therefore this paper examined factors influencing performance of PPPs in SWM at Kinondoni municipality. A cross sectional survey was employed to collect data that was analyzed using descriptive and multiple regression model. Findings showed that poor monitoring and evaluation practices influenced poor performance of PPP in SWM. Moreover, low capacity of the contracted companies, limited accessibility of residential areas and weak enforcement of laws and regulations governing solid waste management had negative influence at 0.05 significant levels. The study recommends the system should establish regular plan in combination with imprompt monitoring to eliminate the effect of possible falsified compliance. Furthermore, the municipal council has to improve town settlements to access the households easily for SWM. Lastly research on end use products of the waste should look at the technical, economic viability of the waste markets for the products processed from the waste for mitigating public health risks associated with SWM.
... Tillering or shooting from the stem bases started in late September, optimized in October about two months after planting, and peaked in November when the effect of treatments was evident (Figure 61a). Plants in WW treated plots produced insignificantly higher total number of tillers per plant (48) than the Tap water irrigated plots (44) and NPK treated plots (38) while plants which received both WW and NPK produced the least number of tillers (36) (Figure 61b). Likewise the flag leaf area was insignificantly higher in WW treated (37.6 cm 2 ) than NPK treated (34.3 cm 2 ) and non-treated plots which were irrigated with tap water only (29.1 cm 2 ) ( Figure 62). ...
This research project was designed to demonstrate that wastewater that has been adequately treated in constructed wetland system can be safely used in irrigation of crops and in fish farming. The general objective of this research project was to improve the productivity of urban / peri-urban agriculture by making use or recycling of wastewater treated in constructed wetlands. The research activity involved Designing and Construction of a Horizontal Subsurface Flow CW (21m x 14m x 1m ) and a Fish Pond (16m x 8m x 1.5m); Application of wastewater in crop irrigation – where suitable quality of wastewater (microbial, nutrients), agronomical application, types of crops, optimum yields, quality and quantity of agricultural of agricultural produce, risk assessment were assessed; studies on the application of wastewater in aquaculture – suitable quality of wastewater (microbial), types of fish species, yields, and quality and quantity of aquaculture produce and finally the studies on value Chain Analysis/ Cost Benefit Analysis/ Attitude and Perception - related to urban / peri urban agriculture.
... Tillering or shooting from the stem bases started in late September, optimized in October about two months after planting, and peaked in November when the effect of treatments was evident (Figure 61a). Plants in WW treated plots produced insignificantly higher total number of tillers per plant (48) than the Tap water irrigated plots (44) and NPK treated plots (38) while plants which received both WW and NPK produced the least number of tillers (36) (Figure 61b). Likewise the flag leaf area was insignificantly higher in WW treated (37.6 cm 2 ) than NPK treated (34.3 cm 2 ) and non-treated plots which were irrigated with tap water only (29.1 cm 2 ) ( Figure 62). ...
This is the final report and the first data of our MORUWASA project, exploring constructed wetlands, receiving effluent from nearby wastewater treatment ponds.
Wastewater reuse in irrigation is an integral part of water resource management (IWRM) that aims to cover agricultural water requirement in water-scarce regions. Taken the example of Yemen, recent study assesses the quality of Sana’a municipal wastewater for irrigation use and addresses the degree of health risk of consuming crops irrigated with wastewater. More than 50 samples from wastewater discharge canal and also from leaves, grains, and fruits were analyzed for physicochemical parameters, heavy metals, and pathogen content. The average of the physicochemical concentrations is 1808 μs/cm, 9.88 meq/L, 7.8, 125, 81.3, 34.9, 360.3, 36.5, 10.93, 94.7, 315, 609, and 215 mg/L for EC, Na, pH, NH3, Ca, Mg, T.H, K, NO3, SO4, BOD5, COD, and SS, respectively. ANOVA test indicates a significant difference between the sampling groups with p value of 0.02. The physicochemical concentrations were high in the influent group and gradually decreased at different distances from the wastewater treatment plant, which may attribute to the role of natural processes (sunlight, air temperature, aeration), and the contact of wastewater flow with earth materials in minimizing their concentrations. Heavy metals, on the other hand, are not at high levels. Their average concentrations in the sampling groups are 0.04, 0.002, 0.20, 0.06, 0.008, and 0.011 ppm for Mn, Cu, Ni, Zn, Cd, and Pb, respectively. The result of fecal contamination, mainly fecal coliforms (FC) and the total coliforms (TC), demonstrated beyond question that pathogen content is extremely high. After treatment, the pathogen number decreases considerably in all sampling groups along the discharge canal with p value of 0.00. Comparison between crops irrigated with wastewater (WW) and those irrigated with groundwater (GW), T-test showed great variation in the number of FC and TC between both fields with p value of 0.03. Increasing the time between irrigation and harvesting has resulted in a massive decrease of pathogen number. After 10 days from the irrigation day, fecal (FC) and total coliforms (TC) decreased to 85% on vegetables, such as cabbage, onion, barley, and leek, and up to 80% on alfalfa. Moreover, the quality of Sana'a wastewater for irrigation use is varied from one site to another. Group two (G2), group four (G4), and group five (G5) displayed lower number of pathogen content and showed acceptable physicochemical concentrations. Thus, water from these locations can be reused to irrigate salt-tolerant vegetables and cocked-eaten crops such as the examples presented in this study.
