Sewage sludge (also termed wastewater sludge) is the main by-product of
the treatment of wastewater. However, disposal of sewage sludge can be
up to 60 % of the total operating cost of a wastewater treatment plant
(WWTP) by consuming enormous quantities of energy.
working with European SMEs to develop a suitable commercial alternative
to existing wastewater sludge treatments. The consortium is taking an
innovative approach to ensure environmental impacts are minimised and
that no additional energy demands will be placed upon current WWTPs.
Project partners' sustainable solution takes the form of a microbial
fuel cell (MFC) coupled to hydrolytic-acidogenic anaerobic digestion
(HA-AD). Researchers are employing these complementary technologies to
achieve an energy system capable of reducing organic compounds in
wastewater by more than 90 % and produce energy at the same time.
Development of MFCs is concentrating on improving the system's
efficiency and cost effectiveness. This will be achieved through the
design of control strategies in order to reach optimal performance as
well as through the development of new cell configuration and cathodes. A
lab-scale HA-AD digester has also been designed and built and initial
tests conducted to determine operational ranges.
The effluent from partial anaerobic digestion of WWTP sludge was
studied with regard to volatile fatty acids production. Results indicate
that the effluent from partial anaerobic digestion is suitable for
bioelectricity production in MFCs. Mathematical models have also been
developed for the HA-AD, MFC and coupled processes.
MFC4SLUDGE will reduce the environmental impact of sewage sludge by
reducing its volume and providing a source of energy, thus valorising
such waste. It will also help improve the competitiveness of
participating SMEs by providing them with valuable know-how and
increased employment opportunities.