Department Sanitation, Water and Solid Waste for Development

Fecal sludge dewatering and supernatant treatment

This research focuses on understanding how the properties of fecal sludge received at treatment plants impacts dewatering performance, and subsequent treatment of supernatant. Our earlier research has confirmed that particle size, extracellular polymeric substances (EPS), lignin, cellulose, hemicellulose and lipids impact dewatering performance. The level of stabilization also plays a role, however, conventional stabilization metrics such as VS/TS and C/N ratios are not relevant for comparison and stabilization metrics that are indicative of the potential for further biological degradation need to be established. Attached growth biofilm reactors are being evaluated for supernatant treatment, along with COD discharge standards for effluents of fecal sludge treatment plants.

Context

The sanitation needs of nearly half (46%) the global population are met through non-sewered sanitation. When containments for onsite storage are full, the fecal sludge that accumulates needs to be emptied and transported to treatment to ensure protection of public and environmental health. Currently, the bulk of the emptied fecal sludge is dumped directly in the environment due to lack of existing treatment units, long haulage distances and high cost of service among other reasons. To maximize the amount of sludge being treated at treatment plants, there is need to improve the understanding of the properties of fecal sludge arriving at these plants for improved dewatering and downstream biological treatment of supernatant after dewatering.

Goal

Developing safely managed solutions through an understanding of faecal sludge that accumulates with microbial degradation and stabilization during storage in containment, in order to develop reliable and safe management of faecal sludge arriving at treatment.

 

 

 

Collaborator

  • Prof. Eberhard Morgenroth, Eawag and ETH Zurich, Zurich, Switzerland
  • Dr. James Tembo and Prof. Joel Kabika, University of Zambia, Lusaka, Zambia
  • Prof. Charles Niwagaba, Makerere University, Kampala, Uganda
  • Naomi Korir, Sanivation, Naivasha, Kenya

Funding

  • Swiss National Science Foundation (SNF)
  • Swiss Agency for Development and Cooperation (SDC)
  • Eawag discretionary funding

Publications

Sam, S. B.; Morgenroth, E.; Strande, L. (2023) Changes in organic fractions, cations, and stabilization from feces to fecal sludge: implications for dewatering performance and management solutions, Journal of Water Sanitation and Hygiene for Development, 13(9), 699-710, doi:10.2166/washdev.2023.086, Institutional Repository
Ward, B. J.; Nguyen, M. T.; Sam, S. B.; Korir, N.; Niwagaba, C. B.; Morgenroth, E.; Strande, L. (2023) Particle size as a driver of dewatering performance and its relationship to stabilization in fecal sludge, Journal of Environmental Management, 326, 116801 (12 pp.), doi:10.1016/j.jenvman.2022.116801, Institutional Repository
Sam, S. B.; Ward, B. J.; Niederdorfer, R.; Morgenroth, E.; Strande, L. (2022) Elucidating the role of extracellular polymeric substances (EPS) in dewaterability of fecal sludge from onsite sanitation systems, and changes during anaerobic storage., Water Research, 222, 118915 (12 pp.), doi:10.1016/j.watres.2022.118915, Institutional Repository
Ward, B. J.; Andriessen, N.; Tembo, J. M.; Kabika, J.; Grau, M.; Scheidegger, A.; Morgenroth, E.; Strande, L. (2021) Predictive models using "cheap and easy" field measurements: can they fill a gap in planning, monitoring, and implementing fecal sludge management solutions?, Water Research, 196, 116997 (12 pp.), doi:10.1016/j.watres.2021.116997, Institutional Repository
Ward, B. J.; Traber, J.; Gueye, A.; Diop, B.; Morgenroth, E.; Strande, L. (2019) Evaluation of conceptual model and predictors of faecal sludge dewatering performance in Senegal and Tanzania, Water Research, 167, 115101 (13 pp.), doi:10.1016/j.watres.2019.115101, Institutional Repository
Moto, N.; Esanju, M.; Andriessen, N.; Kimwaga, R.; Strande, L. (2018) Use of chitosan and Moringa oleifera as conditioners for improved dewatering of faecal sludge, (6 pp.), Institutional Repository
Gold, M.; Harada, H.; Therrien, J.-D.; Nishida, T.; Cunningham, M.; Semiyaga, S.; Fujii, S.; Dorea, C.; Nguyen, V.-A.; Strande, L. (2018) Cross-country analysis of faecal sludge dewatering, Environmental Technology, 39(23), 3077-3087, doi:10.1080/09593330.2017.1374472, Institutional Repository
Gold, M.; Dayer, P.; Faye, M. C. A. S.; Clair, G.; Seck, A.; Niang, S.; Morgenroth, E.; Strande, L. (2016) Locally produced natural conditioners for dewatering of faecal sludge, Environmental Technology, 37(21), 1-13, doi:10.1080/09593330.2016.1165293, Institutional Repository
Ward, B. J.; Sam, S.; Andriessen, N.; Morgenroth, E.; Strande, L. (2018) Research priorities and progress in faecal sludge dewatering, Sandec News, 19, 10-11, Institutional Repository
  • The trials of developing a biomethane potential method for faecal sludge Sandec News No 21, Sam, S., Kapanda, K., Ward, B.J., Tembo, J., Morgenroth, E., Strande, L.
  • Research strategy for overcoming the faecal sludge dewatering bottleneck Sandec News No. 21, Ward, B.J., Sam, S., Kapanda, K., Tembo J.M., Morgenroth, E., Strande, L.
  • Predicting faecal sludge dewatering performance for improved treatment Sandec News No. 20, Ward, B.J., Sam, S., Gueye, A., Diop, B., Morgenroth, E., Strande, L.

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