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

Lead Research Organisation: University of Strathclyde
Department Name: Civil and Environmental Engineering

Abstract

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.

Planned Impact

This research is primarily directed towards developing a technology which will have positive impacts on human health and the environment in developing countries. The commercial viability or efficiency of the technology is a pre-requisite to widespread implementation, so economic impacts are also a secondary priority.
The following groups might benefit from this research:
(1) NGOs providing effective local sanitation infrastructure in developing countries as part of overseas aid and or official development assistance
(2) Developing countries without access to grid electricity, biogas, refrigeration, with agricultural productivity limited by soil fertility and cost of fertilizer
(3) Water companies in developed countries attempting to simultaneously improve treatment standards while reducing cost and carbon footprint at isolated small PE waste water treatment sites.
(4) Developed countries committed to reducing fossil fuel use from manufacture of agricultural fertilisers and greenhouse gas emissions from transport of residual materials used for agricultural benefit

These possible benefits will be achieved in the following ways:
(A) Through more effective elimination of human health pathogens in small-scale, cost-effective local treatment plants in developing countries
(B) By adding renewable energy and useable fertilizer to the health benefits achievable from small-scale sewage-treatment plants in developing countries or crisis zones or areas receiving overseas aid
(C) By reducing the total volume of sludge transported from rural sewage treatment works in developed countries
(D) By earlier capture of biogas and so increasing the recovery rate of the renewable energy potentially available in sewage treatment
(E) By reducing the unnecessary water transported with nutrients in biosolids destined for land application, from 99.6-97% to 60-85% water content by mass, corresponding to a 5- to 100-fold increase in dry matter content (and hence an equivalent reduction in sludge volume)

Publications

10 25 50
 
Description The project concerns faecal sludge dewatering/treatment leading to energy security/generation, sanitation utilising locally-available resource and GHG emission savings. The technical/financial feasibility study is to develop standalone dewatering process for rural UK/EU, increasing energy efficiency/generation, reducing transport costs/carbon footprint and in developing countries (DC) as a low-cost faecal sludge management (FSM) system for decentralised/localised sanitation leading to integrated anaerobic digestion (AD) based off-grid energy generation.
Market opportunity
Two primary business opportunities aimed at UK/EU and DC markets. UK/EU opportunities are based on energy efficiency and energy generation using underutilised energy resource potential of rural primary sludge/industrial waste waters whereas in DC it is based on providing low-cost off-grid energy generation via AD, replacing current non-existent and poor localised sanitation systems and leading to the developments of local entrepreneurship with sales of renewable electricity/biogas/heat, FSM services (non- sewered sanitation provision), fertiliser and clean water. A Millennium Development Goal is to provide sanitation to 50% of estimated 2.6 billion people globally without sanitation with a global annual sanitation market of ~US$8 billion.
Innovation
Testing will build on preliminary work in developing a prototype system that will assess system throughput and efficacy to meet a commercially-viable technology. System design will be tested on a bench scale unit and design and findings will be further enhanced by CFD modelling using Fluent software. Financial viability will be completed together with a detailed system LCA.
Exploitation route
The project will undertake discussions with water companies for an energy-efficient and cost- effective, modular (pre-cursor to AD) and potentially transportable dewatering unit as a valuable process unit operation addition for treating rural primary sludge, with extension to high COD waste waters for wastewater collection companies. The project will further develop financial model reflecting TCO, ROI, IRR and NPV and will determine optimal range for both capex and opex. A similar approach with DC- established teams will approach NGOs/Charities and funding agencies (such as UNDP, DFID).
Outcome and next steps
Present work includes confirming technical and financial viability of the technology and its potential to address all aspects of the energy trilemma
in providing a sanitation and localised energy generation solution that significantly impacts on GHG emissions. Next stage of the project will aim at the building of a pilot-scale unit that will be tested in the UK and in a DC to commercialise the technology.
Exploitation Route Natural Synergies applied for a patent to protect the underlying technology on which our research is based, hence the current need for confidentiality. Patent application GB1804034.5 was lodged on 13/3/18 but was terminated before grant and not in force as of 11 March 2020.
Sectors Agriculture, Food and Drink,Energy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Manufacturing, including Industrial Biotechology

URL https://www.rushlightevents.com/wp-content/uploads/2018/01/Innovate-UK-Energy-Catalyst-Round-4-Directory-of-Projects.pdf
 
Description The company who led the IUK Energy Catalyst Round IV project with which this grant was associated (Natural Synergies Ltd) lodged patent application GB1804034.5 on 13/3/18. However this was terminated before grant and was not in force as of 11/3/20.
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Energy,Environment,Manufacturing, including Industrial Biotechology
Impact Types Societal,Economic

 
Description IUK ECR4 Robust Decentralised Low Energy Faecal Sludge Dewatering leading to Sustainable Energy Resource, Sanitation ,and Clean Water 
Organisation Blue Vine Consulting Limited
Country United Kingdom 
Sector Private 
PI Contribution Contributing key research findings to this accompanying Innovate UK contract for the main Energy Catalyst Round IV award
Collaborator Contribution Accompanying Innovate UK contract for Energy Catalyst Round IV to specify and apply the results of this research grant
Impact Currently confidential
Start Year 2017
 
Description IUK ECR4 Robust Decentralised Low Energy Faecal Sludge Dewatering leading to Sustainable Energy Resource, Sanitation ,and Clean Water 
Organisation Natural Synergies Ltd
Country United Kingdom 
Sector Private 
PI Contribution Contributing key research findings to this accompanying Innovate UK contract for the main Energy Catalyst Round IV award
Collaborator Contribution Accompanying Innovate UK contract for Energy Catalyst Round IV to specify and apply the results of this research grant
Impact Currently confidential
Start Year 2017
 
Description IUK ECR4 Robust Decentralised Low Energy Faecal Sludge Dewatering leading to Sustainable Energy Resource, Sanitation ,and Clean Water 
Organisation Practical Action
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Contributing key research findings to this accompanying Innovate UK contract for the main Energy Catalyst Round IV award
Collaborator Contribution Accompanying Innovate UK contract for Energy Catalyst Round IV to specify and apply the results of this research grant
Impact Currently confidential
Start Year 2017