Christopher Andrew Buckley

University of KwaZulu-Natal | ukzn · School of Engineering

Forward osmosis with an ammonium bicarbonate draw solution was investigated as a low energy non-sewered sanitation solution, to recover nutrients and water from source separated urine. Stored urine collected from Urine Diversion Dry Toilets in the eThekwini Municipality (Durban), South Africa was used as the feed solution. Water recoveries of up to...

In striving to achieve sustainable sanitation, one challenge is to ensure hygienic treatment of faecal sludge from on-site sanitation. Thermal drying is an important treatment step for moisture removal and disinfection. Improved understanding of the drying process is crucial for the proper design of treatment technologies for faecal sludge. In this...

Contact surfaces within shared sanitation facilities could lead to disease transmission due to contamination. In this study, we applied metagenomics, by targeting the 16S rRNA gene region using illumina sequencing to determine the common bacterial communities on key contact surfaces in shared sanitation facilities within a metropolitan municipality...

The study assessed the suitability of two effluent types, namely anaerobic filtered (AF) and horizontal flow constructed wetland (HFCW) effluent for Moistube irrigation (MTI). Secondary to this, the study determined the plugging coefficients (α) on MTI for the respective effluents. The feed water was supplied from a raised tank (3.5 m), and mass-fl...

This study explicates the scope of published literature on the influence of attitudes and perceptions on the intention to use human excreta and human excreta derived materials in agriculture. Using a scoping review methodology, search results from Scopus and Web of Science were screened and synthesized using the DistillerSR web-based application. O...

Using effluent from the anaerobic baffled reactor (ABR) of the decentralised wastewater treatment system (DEWATS) as a sole nutrient source is not sufficient for tomato plants grown in hydroponic system. The study investigated the effects of commercial hydroponic fertilizer mix (CHFM) combined with ABR effluent on tomato growth and yield. A media-b...

We developed a simple process that could encourage people to recycle urine. In our process, freshly collected urine is first made alkaline (high pH) to prevent the reaction that produces ammonia and urine’s typical pungent smell. Then, by evaporating water, urine is reduced into a dry powder that captures all its nutrients.

Challenges associated with rapid population growth, urbanization, and nutrient mining have seen increased global research and development towards ‘waste to wealth’ initiatives, circular economy models, and cradle-to-cradle waste management principles. Closing the nutrient loop through safe recovery and valorization of human excreta for agricultural...

In order to treat faecal sludge from ventilated improved pit (VIP) latrines, eThekwini Municipality (Durban, South Africa) developed an infrared dryer, ‘LaDePa’ (Latrine Dehydration Pasteurization). Parameters that influence its operation were investigated using a laboratory-scale replica of the full-scale machine. For this, faecal sludge collected...

Drying is one of the treatment techniques used for the dual purpose of safe disposal and energy recovery of faecal sludge (FS). Limited data are available regarding the FS drying process. In this paper the drying properties of FS were investigated using samples from ventilated improved pit (VIP) latrines and urine diversion dry toilets (UDDT) and a...

Disposal of human excreta derived materials (HEDM), particularly domestic wastewater, presents a challenge in areas served with on-site sanitation systems, most particular in informal settlements. The use of HEDM for agricultural food production represents a couple of opportunities such as improved sanitation, household food security as well as the...

The need for the optimal use of land, without a yield penalty, in urban and peri-urban (UP) settlements is vital. This study investigated the effect of intercropping madumbe and rice with respect to yield and land productivity when irrigated with anaerobic baffled reactor (ABR) effluent under different irrigation water management techniques. It was...

Ascaris Lumbricoides is the most common helminth of human health importance, and the most resilient helminth found in faecal sludge. There are numerous types of sludge treatments; however, heating and drying are most commonly used for pathogen inactivation. Ascaris suum eggs were heated in a water bath at 40–55 °C for 10 seconds to 60 minutes in wa...

There is increasing interest and wide recognition of the potential use of human-excreta derived materials (HEDM) as fertilizer to supply essential nutrients needed for crop production. However, most work on HEDM has focussed on yield responses using soils and very little done on soil-less media using hydroponics. Further, physiological responses of...

This work explores the effect of drying on the chemical and physical properties of faecal sludge, and evaluates the reuse potential of the dried material. For the purpose of this study, the nutrient content, calorific value and thermal properties were determined for faecal sludge samples dried at different moisture contents and under different dryi...

Water is becoming a scarce resource in many parts of South Africa and, therefore, numerous plans are being put in place to satisfy the increased urban demand for this resource. Two of the methods currently considered are desalination of seawater and reuse of mine-affected water based on the use of reverse osmosis (RO) membranes. Due to their high e...

Efforts to recover nutrients from wastewater have drawn interest in effluent polishing with duckweed, a small angiosperm known to grow in high nutrient environments. One important consideration is that pathogens may be transferred to suspended duckweed biomass and ultimately spread into agricultural or other environmental settings. Our objective wa...

Municipalities in South Africa face problems in providing sanitation to unserved informal settlements in peri-urban areas and rural nodes. The Decentralised Wastewater Treatment System (DEWATS) connected to community ablution blocks can be an option, with the treated effluent then applied to agricultural land. However, the management of treated was...

Shared sanitation is widely proposed as a means to increase access to improved sanitation. There are few reports of a causal relationship between the use of shared sanitation and communityacquired diarrhoea. This paper presents an analytical review of studies that have investigated the relationship between the use of shared sanitation and the preva...

The need to cultivate effluent-irrigated rice is paramount and synonymous with treated wastewater reuse, recycling and water resources management. A trial in a peri-urban set-up with a low-cost decentralized wastewater treatment system (DEWATS) was carried out in the 2017 and 2018 cropping seasons to assess the effect of irrigation water reuse mana...

This study evaluated the effects of irrigation water management techniques on the growth and yield parameters of madumbe (Colocasia esculenta) irrigated with anaerobic filter (AF) effluent. The irrigation water management treatments considered were alternate wetting and drying (AWD), continuous flooding irrigation (CFI) and wetting without flooding...

The Decentralised Wastewater Treatment System (DEWATS) provides low cost onsite sanitation to residents living in informal settlements. Wastewater management through agriculture prevents environmental pollution and promotes sustainable agriculture. This study investigated the effects of fertigation with DEWATS effluent to field capacity in three So...

The study evaluated the effect of irrigation water management techniques using anaerobic baffled reactor (ABR) effluent on the growth and yield of rice. It was hypothesized that irrigation techniques with ABR effluent have a significant effect on the growth, yield of rice, water productivity (WP) and water balance (WB). The experimental setup was a...

Water, Sanitation and Hygiene

This work aims at characterizing the rheological properties of faecal sludge from Ventilated Improved Pit (VIP) latrines and their implication on pit emptying. Faecal sludge was sampled from 3 pit latrines located in the eThekwini Municipality (Durban, South Africa). Samples were taken at different positions within the pit. For each of the samples,...

A multiple criteria decision analysis (MCDA) was developed for the selection of sanitation systems. This decision support system was aimed at assisting municipal engineers to design and implement sustainable solutions to meet a municipality’s obligation to provide free basic sanitation (FBS). Multi-attribute value theory (MAVT) was selected as the...

This paper studies a faecal sludge treatment process, LaDePa (Latrine Dehydration and Pasteurization), which includes: (i) the characterization of the rheological and plastic behaviour of faecal sludge in the feeding section; (ii) the study of the drying and pasteurization performance of the process using a laboratory-scale prototype; and (iii) an...

The Decentralised Wastewater Treatment System (DEWATS) can provide a potential sanitation solution to residents living in informal settlements with the effluent produced being used on agricultural land. This paper reports on a first step to assess the technical viability of this concept. To do so a pilot DEWATS plant was connected to 83 houses in t...

South Africa has the largest occurrence of the human immune deficiency virus (HIV) in the world but has also implemented the largest antiretroviral (ARV) treatment programme. It was therefore of interest to determine the presence and concentrations of commonly used antiretroviral drugs (ARVDs) and, also, to determine the capabilities of wastewater...

Decentralized wastewater treatment systems (DEWATS) using anaerobic treatment are increasingly being considered for wastewater treatment with options for non-potable water reuse at the community scale. One challenge for ensuring performance and reliability of DEWATS is the lack of suitable on-site sensors to monitor failure or contamination events....

Trash in pit latrines is one of the largest challenges facing pit emptying technologies, including the powered auger (the Excrevator), developed for improved emptying in lower- and lower-middle income countries. This study focused on two trash removal methods in conjunction with pit emptying by the Excrevator: (1) simultaneous removal of trash with...

This study was part of the VUNA project aimed to develop an affordable sanitation system that produces a valuable fertiliser, reduces pollution of water resources and promotes health. Urine diversion dry toilets (UDDTs) simplify the on-site hygienisation of faeces and allow for nutrient recovery from urine. Social acceptance is vital for the implem...

Human urine can be processed into market-attractive fertilizers like struvite; however, concerns regarding the microbial safety of such products remain. The present study evaluated the inactivation of in situ heterotrophs, total bacteria as observed by flow cytometry, and inoculated Enterococcus spp. and Salmonella typhimurium during the drying of...

This study investigated the gross heat value (MJ/kg) of the scum from 14 Wastewater Pumping Stations (WWPS) situated in the residential and industrial area in the eThekwini Municipality, Durban, South Africa. A manual sampling procedure was carried out to collect the scum formed from these WWPS. The gross calorific value of the scum samples was ana...

Urine ultrafiltration (UF) was studied in terms of flux, permeability, resistance and fouling. Two types of samples were used: stored urine representing the feedstock obtained from urine diversion dry toilets; diluted stored urine representing the feedstock obtained from urinals. Three different filtration experiment sets were adopted in this study...

South Africa is a water-scarce country with increasing pressure on its water resources. Urgent interventions are needed to protect water security within this rapidly developing country. This paper reports on an interdisciplinary Water Security Colloquium, convened by the South African Young Academy of Science in 2014. A selected group of water prof...

A review concerning the anaerobic baffled reactor (ABR) treating communal wastewater under mesophilic conditions is presented. Existing studies indicate strong resilience of the reactor towards loading variations and shock-loads. The compartmentalisation of the ABR is a strongly stabilising factor with feed fluctuations being evened out across reac...

Decentralized Wastewater Treatment Systems (DEWATS) are increasingly being recognized by decision makers and city developers across the world as an option for service delivery in densely populated low-income areas. However, little knowledge and field-data are available on some key design-, operation- and monitoringparameters. This paper addresses t...

An Analysis of FOG/Scum in eThekwini Municipality Pump Stations

The intrinsic fluorescence of aquatic organic matter emitted at 350nm when excited at 280nm correlates widely with water quality parameters such as biochemical oxygen demand. Hence, in sewage-impacted rivers and groundwater, it might be expected that fluorescence at these wavelengths will also correlate with the microbial water quality. In this pap...

Viscous heating by extrusion of faecal material obtained from ventilated improved pit (VIP) latrines can be used to deactivate soil-transmitted helminth (STH) eggs by increasing the temperature of faecal sludge uniformly. Viscous heating can deactivate STH eggs present in sludge to make the material safer to transport, dispose of, or use in agricul...

Sludge content in VIP latrines is degraded mainly under anaerobic conditions and the process is relatively slow. At varying stages of digestion within pit latrines, sludge accumulates and odour and fly nuisance may occur which could pose risks to public health and the environment. Management of accumulated sludge in pit latrines has been a major pr...

In recent years, a large number of urine-diverting dehydration toilets (UDDTs) have been installed in eThekwini to ensure access to adequate sanitation. The initial purpose of these toilets was to facilitate faeces drying, while the urine was diverted into a soak pit. This practice can lead to environmental pollution, since urine contains high amou...

This study investigated the chemical and thermal properties of faecal sludge from 10 dry VIP latrines in Bester's Camp in the eThekwini Municipality, Durban, South Africa. Faecal sludge samples were selected at different depths and from the front and back sections of 10 VIP latrines during a manual emptying process. The samples were analysed for: m...

The aim of the present paper was to move water through a reservoir network in such a way as to meet consumer demands and level constraints, minimise the cost of electricity, and minimise the loss of chlorine. This was to be achieved by choosing the switching intervals of reservoir inlet pumps and valves, at the same time complying with the allowed...

In the present study we attempted to develop a reactor system to recover phosphorus by struvite precipitation, and which can be installed anywhere in the field without access to a laboratory. A reactor was developed that can run fully automated and recover up to 93% of total phosphorus (total P). Turbidity and conductivity signals were investigated...

In the present study we attempted to develop a reactor system to recover phosphorous by struvite precipitation which can be installed anywhere in the field without access to a laboratory. A reactor was developed that can run fully automated and recover up to 93 % of total phosphorus (total P). Turbidity and conductivity signals were investigated as...

An analysis of viscosity data from sets of raw data on the shear rheological properties of fresh human faeces was performed to generate model constants that can be used for the design of faecal treatment processes. The models selected are standard choices in computational fluid dynamics software for shear-thinning fluids. Initial screening for mode...

A linear programming technique is proposed to balance the flows in a network, matching flow measurements where available. Where necessary, a “leak-out” flow is invoked on a pipe section in order to achieve the balance. Usually, multiple solutions are possible, and these are sounded out by progressively increasing an integrity weight for each pipe s...

In recent years, a large number of urine-diverting dehydration toilets (UDDTs) has been installed in eThekwini to ensure access to adequate sanitation. The initial purpose of these toilets was to facilitate faeces drying, while the urine was diverted into a soak pit. This practice can lead to environmental pollution, since urine contains high amoun...

Dry sanitation requires the handling of faeces, which vary in age and degree of transformation. Rheological data are necessary to support the design of equipment to handle faeces. The rheological properties of fresh human faeces were measured using a variable-speed rotational rheometer. Samples were further tested for moisture content, total solids...

A glasshouse study was carried out to assess the availability to maize of nutrients from anaerobic baffled reactor (ABR) effluent. Maize was grown for 6 weeks in pots with three contrasting soils namely a sandy soil (Cartref (Cf), Typic Haplaquept), an organic, acidic soil (Inanda (Ia), Rhodic Hapludox) and a clayey soil (Sepane (Se), Aquic Haplust...

In recent years there has been a growing body of knowledge exploring the benefits of using sanitation-derived nutrients. Such studies aim to uncover strategies that facilitate nutrient recovery from urine and faecal sludge for agricultural use. This paper presents the findings of a study which assessed the willingness to handle and use urine in agr...

A soil column study was undertaken in the laboratory with three contrasting soil types namely a sandy soil (Longlands (Typic Plinthaquult), E horizon), an organic soil (Inanda (Rhodic Hapludox), A horizon) and a clayey soil (Sepane (Aquic Haplustalf), A horizon). Anaerobic baffled reactor (ABR) effluent was leached through the soil and distilled wa...

The provision of communal water and sanitation facilities has been mandated by the South African Government as an interim measure for informal settlement upgrading. These services form the first step in the upgrading process and are essential in meeting the basic needs of the community. The eThekwini municipality is rolling out community ablution b...

Population growth, climatic changes and over-exploitation of natural resources are at the basis of the world’s food crisis, which counts almost one million people without sufficient food sustenance. These changes require novel environmental practices which are based on nutrient recovery and management in agriculture. This contribution analyses and...

Population growth, climatic changes and over-exploitation of natural resources are at the basis of the world's food crisis, which counts almost one million people without sufficient food sustenance. These changes require novel environmental practices which are based on nutrient recovery and management in agriculture. This contribution analyses and...

The idea of implementing ancient water and wastewater technologies in the developing world is a persuasive one, since ancient systems had many features which would constitute sustainable and decentralised water and sanitation (WATSAN) provision in contemporary terminology. Latest figures indicate 2.6 billion people do not use improved sanitation an...