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Assessing nutrient flows in septic tanks by eliciting expert judgement
Montangero, Agnes
"Simple models based on the physical and biochemical processes occurring in septic tanks, pit and urine diversion latrines were developed to determine the nutrient flows in these systems. Nitrogen and phosphorus separation in different output materials from these on-site sanitation installations were thus determined. Moreover, nutrient separation in septic tanks was also assessed through literature values and by eliciting expert judgement. Use of formal expert elicitation technique proved to be effective, particularly in the context of developing countries where data is often scarce but expert judgement readily available. In Vietnam, only 5–14% and 11–27% of the nitrogen and phosphorus input, respectively, are removed from septic tanks with the faecal sludge. The remaining fraction leaves the tank via the liquid effluent. Unlike septic tanks, urine diversion latrines allow to immobilise most of the nutrients either in form of stored urine or dehydrated faecal matter. These latrines thus contribute to reducing the nutrient load in the environment and lowering consumption of energy and non-renewable resources for fertiliser production." Water Research 2007, Volume 41, Number 5, pp. 1052-1064 Available from: ScienceDirect
Solid–liquid separation of faecal sludge using drying beds in Ghana
Cofie, Olufunke
This study investigated the possibility of recycling nutrients in human excreta and municipal solid waste for use in agriculture. It reports on the use of drying beds in separating solid and liquid fractions of faecal sludge (FS) so that the solids can be co-composted and the organic matter and part of the nutrients captured for urban agriculture... Water Research 2006, 40:1, pp. 75-82 Available Online from: Science Direct
Isolation of Salmonella sp. in sludge from septage treatment plant
Sanguinetti, Graciela
"Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. [...]" Water Science & Technology 2005, Volume 51, Number 12, pp. 249-252 Available for purchase from: IWA Publishing
A Discrete-Event Dynamic Systems Approach for Environmental Decision-Support
Huang, Dong-Bin
PhD Thesis, Swiss Federal Institute of Technology Zurich, Switzerland In his thesis, Dong-Bin Huang developed an event-based dynamic material flow and life-cycle-inventory modeling method and applied it in the urban area of Kunming (China) for urban water resource planning and pollution control of Dianchi Lake. Download
Reuse and Recycle of Bio-residue (percolate) from Constructed Wetland Treating Septage
Hadsoi, Sukon
Master's Thesis, Asian Institute of Technology, Thailand "The prime objective of this research is to investigate the suitability of percolate from constructed wetland (CW) treating septage in agricultural application with the specific focus on determination of appropriate application ratio of percolate on sunflower plantation and crop yields." Download
Fäkalschlammbehandlung in den Tropen am Beispiel von Vererdungsbeeten
Heinss, Udo
"Ein großer Anteil der in tropischen Großstädten eingesammelten Fäkalschlämme gelangt unbehandelt in die Umwelt. Daher ist es notwendig, neben angepassten Schlammbehandlungsverfahren auch Fäkalschlammmanagement-Konzepte zu entwickeln. Eine mögliche Behandlungsoption, die Schlammvererdung in bepflanzten Trockenbeeten, konnte erfolgreich in Bangkok getestet werden. Dabei wurde eine hohe optimale Feststoffbeladung von 250 kg TS/m2 d gefunden." KA- Abwasser, Abfall 2003, Vol. 50, No. 9, pp. 1162-1167 Download
Confronting limitations
Huang, Dong-Bin
"Despite continuous investment and various efforts to control pollution, urban water environments are worsening in large parts of the developing world. In order to reveal potential constraints and limitations of current practices of urban water management and to stimulate proactive intervention, we conducted a material flow analysis of the urban water system in Kunming City. The results demonstrate that the current efficiency of wastewater treatment is only around 25% and the emission of total phosphorous from the city into its receiving water, Dianchi Lake, is more than 25 times higher than its estimated tolerance. With regard to the crisis of water quantity and quality, the goal of a sustainable urban water environment cannot be attained with the current problem-solving approach in the region due to the technical limitations of the conventional urban drainage and treatment systems. A set of strategies is therefore proposed. The urban drainage system in Zurich is used as a reference for a potential best-available technology for conventional urban water management (BAT) scenario in terms of its low combined frequency of sewer overflow." Journal of Environmental Management, online since July 2006 Available online from: ScienceDirect
Treatment of septage in constructed wetlands in tropical climate
Koottatep, Thammarat
In tropical regions, where most of the developing countries are located, septic tanks and other onsite sanitation systems are the predominant form of storage and pre-treatment of excreta and wastewater, generating septage and other types of sludges. The septage is disposed of untreated, mainly due to lack of affordable treatment options. This study presents lessons that have been learned from the operation of pilot-scale constructed wetlands (CWs) for septage treatment since 1997. The experiments have been conducted by using three CW units planted with narrow-leave cattails (Typha augustifolia) and operating in a vertical-flow mode. Based on the experimental results, it can be suggested that the optimum solids loading rate be 250 kg TS/m2 yr and 6-day percolate impoundment. At these operational conditions, the removal efficiencies of CW units treating septage at the range of 80–96% for COD, TS and TKN were achieved. The biosolid accumulated on the CW units to a depth of 80 cm has never been removed during 7 years of operation, but bed permeability remained unimpaired. The biosolid contains viable helminth eggs below critical limit of sludge quality standards for agricultural use. Subject to local conditions, the suggested operational criteria should be reassessed at the full-scale implementation. Keywords Nutrient removal; operation; helminth eggs; septage treatment; vertical-flow constructed wetlands Water Science and Technology 2005, Vol. 51, No. 9, pp. 119–126 Available for purchase from: IWA Publishing
Assessment of water quality problems and mitigation potentials by using material flow analysis
Schaffner, Monika
"Material flow analysis (MFA) is a promising tool for river water quality management. Based on orders-ofmagnitude estimations, the approach provides an overview of pollution problems and their dimensions in a river system, allowing to identify key sources and pathways of pollution, and to evaluate mitigation priorities. The current study aims at investigating MFA to assess river water quality problems and mitigation measures in developing countries, based on a case-study carried out in the Tha Chin River Basin (TRB), Thailand." Proceedings of the International Symposium on the Role of Water Sciences in Transboundary River Basin Management, Ubon Ratchathani (Thailand), 10-12 March 2005 Download PDF from: MekongBasinResearchNetwork
Wiederverwenden statt verschwenden / Recycler au lieu de jeter
Zurbruegg, Christian
This article discusses alternative sanitation systems enabling the reuse of human waste (organic solid waste, urine, faeces) in agriculture. Case studies in Mexico, China, and Ghana illustrate how the concept of closing nutrient cycles can be succesfully implemented. Helvetas Partnerschaft 2006, Number 183, pp.16-18 Download from Helvetas: German version / French version
From conventional to advanced environmental sanitation
Schertenleib, Roland
"The basic concept of collecting domestic liquid waste in water-borne sewer systems goes back more than 100 years and became in the last century the conventional approach to sanitation in urban areas. Over the years, these sewage disposal systems had to be successively upgraded by additional sewage treatment plants increasing investment, operating and maintenance costs. Although these conventional sanitation systems could improve significantly the public health situation in those countries who could afford to install and operate them, it is highly questionable, if they are economically and ecologically sustainable. The large number of people in the developing world who still do not have access to adequate sanitation is a clear indication that the conventional approach to sanitation is not adapted to the socio-economic condition prevailing in most countries of Africa, Asia and Latin America. Advanced environmental sanitation is aiming not only to protect public health and the integrity of aquatic ecosystems but also to conserve precious freshwater and non-renewable resources. The Bellagio Principles and the Household Centred Environmental Sanitation Approach (HCES) are suggested as guiding principles and a new approach for planing and designing advanced (sustainable) environmental sanitation systems." Water Science & Technology 2005, Vol. 51, No. 10, pp. 7–14 Available from: IWA Publishing Online
Cotreatment of sewage and septage in waste stabilization ponds
Ingallinella, A.M.
"A one year study was carried out in a waste stabilization ponds system where septage and sewage are cotreated. The system consists of two septage ponds which operate alternately followed by two ponds in series which receive the combined effluent. The septage ponds also act as evaporation ponds for the accumulated sludge. The monitoring program was divided in two phases. The results of the first phase indicate that the effluent of septage ponds has an adequate quality to be discharged into the waste stabilization ponds designed to treat sewage and that is possible to use the septage ponds to dry the accumulated sludge. Further investigation is needed to find suitable post-treatment of the sludge in order to use it in agriculture." Water Science & Technology 2002, Vol .45, No. 1, pp. 9–15 Available from: IWA Publishing
The Challenge of Faecal Sludge Management in Urban Areas
Ingallinella, A.M.
In urban centres of industrialising countries, the majority of houses are served by on-site sanitation systems such as septic tanks and unsewered toilets. The faecal sludges (FS) collected from these systems are usually discharged untreated into the urban and peri-urban environment, posing great risks to water resources and to public health. Contrary to wastewater management, the development of strategies to cope with faecal sludges, adapted to the conditions prevailing in developing countries, have long been neglected. The authors describe the current situation and discuss selected issues of FS management. A proposal is made for a rational setting of sludge quality or treatment standards in economically emerging countries [...]. Water Science and Technology 2002, Vol. 46, No. 10, pp. 285-294. Available for purchase from: IWA Publishing
Condition d'Acclimatement d'Echinochoa pyramidalis (Lam.) Hitchc. & Chase et de Cyperus papyrus L. pour le Traitement de Bous de Vidange
Tsama Njitat, Valérie
Master's Thesis, Université de Yaoundé, Cameroun The main macrophytes that are used in constructed wetlands for treating faecal sludge or waste water in Europe and Asia are Typha spp. and Phragmites spp. Asia. These plants are absent in Cameroon. This study was designed to study the conditions of acclimatization of two indigenous species in Cameroon (Cyperus papyrus L. and Echinochoa pyramidalis (Lam.) Hitchc. & Chase cultivated in vertical flow constructed wetlands system fed with rough faecal sludge. Download
Implantation et dimensionnement d’une station de traitement des boues de vidange dans la commune de Ouahigouya (Burkina Faso)
Diagne, Etienne
Mater's Thesis, Ecole Inter-Etats d’Ingénieurs de l’Equipement Rural de Ouagadougou, Burkina Faso Download
Wastewater Effluent Polishing Systems of Anaerobic Baffled Reactor Treating Black-water from Households
Koottatep, Thammarat
"This paper presents the outcomes of pilot-scale experiments on anaerobic baffled reactor (ABR) and polishing systems for the treatment of domestic blackwater, aimed at determining the treatment performance of different integrated low-cost wastewater treatment systems, comprising one ABR as first treatment step followed by three polishing steps operated in parallel, namely an anaerobic filter an intermittent sand filter and a vertical flow constructed wetland. A mixture of septage and domestic wastewater was used as influent wastewater, resulting in influent chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations of 1,000 and 300 mg/L, respectively. The ABR system operated at a HRT of 48h could achieve average COD, suspended solids (SS) and total nitrogen (TN) removal efficiencies of 90%, 93% and 50%, respectively. The highest treatment performances in the sand filter and constructed wetland units were reached at HLR of 7 – 10 and 6 – 10 cm/day, respectively, while HRT in the range of 3 - 4 days led to the highest treatment efficiencies in the anaerobic filter. The national effluent standards of Thailand were respected by all systems in terms of average TSS and BOD concentrations. Rather than concluding which system is the most appropriate, the paper discusses specific fields of application for the different systems." Proceedings of the 7th Specialised Conference on Small Water and Wastewater Systems, 7-10 March 2006, Mexico City, Mexico Download
Potentials and Limitations of Existing Technical Alternatives on Waste and Wastewater Management in Cat Bi Ward, Haiphong City, Vietnam
Bao, Pham Ngoc
Master's Thesis, Asian Institute of Technology, Thailand "This study focus on investigation in details the potential and limitations of existing technical alternatives on human excreta and domestic wastewater management in Haiphong, with a case study in Cat Bi ward, where there is a huge potential for using of onsite and decentralised sanitations for human excreta and wastewater disposal and where people having high potential of willing to pay for wastewater and sanitation fee. SWOT analysis technique has been used in the evaluation process. [...]" Download
Assessment of on-site Sanitation Systems in Peri-urban Communities by Using Selected Sustainability Indicators
Jiawkok, Supattra
Master's Thesis, Asian Institute of Technology, Thailand In her MSc thesis, Supattra Jiawkok assessed the existing on-site sanitation systems treating black water in peri-urban communities including (i) the one-cesspool system, (ii) the two-cesspool system in series and (iii) the package tank system at Muaeng Klong Luang Municipality, Klong Luang district, Pathum Thani Province, Thailand. Download
Vers un Assainissement Urbain Durable en Afrique Subsaharienne
Koanda, Halidou
PhD Thesis, Swiss Federal Institute of Technology Lausanne, Switzerland The thesis developed tools for sustainable faecal sludge management: stakeholder analysis combined with stakeholder involvement as a planning model, sociopsychological model for understanding the population willingnesss to improve faecal sludge management, sustainable money fluxes based on sanitations taxes and emptying fees. Download
Development of Database on Faecal Sludge Collection, Treatment and Disposal in Thachi, Chaopraya and Bangpakong River Basins, Thailand
Petchrat, Supapan
Master's Thesis, Asian Institute of Technology, Thailand "At present, Thailand does not have action plan and appropriate policy for Fecal Sludge (FS) management and lacking of data on FS collection, treatment and disposal. Nevertheless, FS management has become the responsibility of local authorities. The purpose of this study is to develop database on FS collection, treatment and disposal in three main river basins in central plain of Thailand, namely, Thachin, Chaopraya and Bangpakong." Download
Implementing the Bellagio Principles in Urban Environmental Sanitation Services
[Swiss Federal Institute of Aquatic Science and Technology], Eawag
This guideline presents the Household-Centred Environmental Sanitation (HCES) approach, which was developed by an Environmental Sanitation Working Group of the Water Supply and Sanitation Collaborative Council (WSSCC). Download PDF or order hard copy from: Eawag (Available in English and French)
An Integrated Approach to Environmental Sanitation and Urban Agriculture
Schertenleib, Roland
"Environmental sanitation comprises disposal and treatment of human excreta, solid waste and wastewater, control of disease vectors, and provision of washing facilities for personal and domestic hygiene. The conventional approach to environmental sanitation is characterised by a linear waste management system, where valuable plant nutrients are often not only wasted, but also create pollution problems in receiving waters. Closing the nutrient loop is one of the main objectives of a more ecological approach to environmental sanitation. Reuse of wastewater and organic waste in urban agriculture may contribute to closing this nutrient loop. In addition to food security and income generation, urban agricultural activities can thus help to improve public health and resource management. However, some urban agricultural processes, such as “agricultural practices”, “soil quality management” and “irrigation”, still requires further research." ISHS Acta Horticulturae 2004, No. 643: International Conference on Urban Horticulture Available from: ISHS Acta Horticulturae
Integrated faecal sludge treatment and recycling through constructed wetlands and sunflower plant irrigation
Koottatep, Thammarat
"Faecal sludge (FS) from the on-site sanitation systems is a nutrient-rich source but can contain high concentrations of toxic metals and chemicals and infectious micro-organisms. The study employed 3 vertical-flow CW units, each with a dimension of 5×5×0.65 m (width×length×media depth) and planted with cattails (Typha augustifolia). At the solid loading rate of 250 kg total solids (TS)/m2.yr and a 6-day percolate impoundment, the CW system could achieve chemical oxygen demand (COD), TS and total Kjeldahl nitrogen (TKN) removal efficiencies in the range of 80–96%. A solid layer of about 80 cm was found accumulated on the CW bed surface after operating the CW units for 7 years, but no clogging problem has been observed. The CW percolate was applied to 16 irrigation sunflower plant (Helianthus annuus) plots, each with a dimension of 4.5×4.5 m (width×length). In the study, tap water was mixed with 20%, 80% and 100% of the CW percolate at the application rate of 7.5 mm/day. Based on a 1-year data in which 3 crops of plantation were experimented, the contents of Zn, Mn and Cu in soil of the experimental plots were found to increase with increase in CW percolate ratios. In a plot with 100% of CW percolate irrigation, the maximum Zn, Mn and Cu concentrations of 5.0, 12.3 and 2.5 mg/kg, respectively, were detected in the percolate-fed soil, whereas no accumulation of heavy metals in the plant tissues (i.e. leaves, stems and flowers) of the sunflower were detected. The highest plant biomass yield and oil content of 1000 kg/ha and 35%, respectively, were obtained from the plots fed with 20% or 50% of the CW percolate." Water Science and Technology 2006, Vol. 54, No. 11-12, pp. 155–164 Available from: IWA Publishing