Robust Decentralised Low Energy Faecal Sludge Dewatering leading to Sanitation, Clean Water and Sustainable Energy Resource

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The project concerns dewatering/treatment of faecal sludge (black waters). Natural Synergies Ltd's (NS) aims are to develop a stand-alone dewatering process for rural areas of the UK/EU, reducing transport costs and carbon footprint and in developing countries as a low cost decentralised/localised sanitation system. The developed system can be also be used as a pre/post-cursor to a small scale anaerobic digestion (a follow-on proposal) or thermal unit, leading to closed loop decentralised, localised sanitation and off-grid energy generation. The dewatering process being developed will incorporate ultrasound to make available free, interstitial and cell water, together with electrokinetics to drive/separate water from faecal sludge via filter mesh. Preliminary work has shown potential for high levels of dewatering (15 - >40 % DM) and pathogen reduction (incl. helminths) at low energy inputs. System design will aim at non-specialised component manufacture, where possible, using local industries.Our vision is to develop an entire new system of treating pit latrine wastes in developing countries, which not only generates renewable energy, but also a safe, useable fertilizer. In theory, this could be achieved now using conventional process technology. What is lacking, however, is a small scale robust system at relatively lower cost that can be operated with ease in remote areas. Our research contribution to delivering this is focussing on two specific challenges: Firstly, how to destroy human parasitic worms or their eggs, so as to allow safe reuse of the solidified material for agricultural fertilizer; Secondly, can we use locally available plant material to simultaneously increase the amount of energy, as biogas, which can be produced. The systems that Natural Synergies Ltd have been developing are highly effective but also highly innovative. We need to be sure of the overall environmental performance and social benefits of any new system, as well as its cost effectiveness. If successful this technology could also offer significant cost-savings and environmental benefits in developed countries at small-scale wastewater treatment plants in remote locations (e.g. Scottish Highlands), reducing road-tanker traffic, transport fuels and carbon emissions.