What are the true temperature limits for the anaerobic treatment of domestic wastewater?

Lead Research Organisation: Newcastle University
Department Name: Civil Engineering and Geosciences

Abstract

The need for carbon neutral or carbon negative domestic wastewater treatment is prompting a re-examination of the use of anaerobic systems to treat domestic wastewater at ambient temperatures. This might be achieved using traditional methanogenic or electrogenic systems (microbial fuel cells). However, temperature is the Achilles heel of such systems. Low temperatures may impede or stop both the production of methane or the initial hydrolysis and fermentation that must take place in all systems. However the true limits of such systems with respect to temperature are still not well understood. The best environmental engineering research to date appears to have succeeded in acclimatising mesophilic organisms. There is no reason to believe that this represents the true limits of anaerobic digestion. Preliminary evidence from our own arctic fieldwork and the literature suggests that adequate rates may be achievable at temperatures as low as 5oC. We wish to determine the true limits of anaerobic systems for the treatment of domestic wastewater by comparing the performance of reactors seeded with cold adapted and non-cold adapted organisms at a variety of temperatures. We will determine if there is a distinct psychrophilic community by using both novel and classical methods to identify, isolate and characterise representatives of the key functional groups in these communities. The putative cold adapted communities will be challenged to gain insight into their robustness in warmer conditions. The design implications of degree of cold adaption attained will be explored and communicated to our colleagues in research and practice.

Publications

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Bowen EJ (2014) Low-temperature limitation of bioreactor sludge in anaerobic treatment of domestic wastewater. in Water science and technology : a journal of the International Association on Water Pollution Research

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Petropoulos E (2018) Lipolysis of domestic wastewater in anaerobic reactors operating at low temperatures in Environmental Science: Water Research & Technology

 
Description We have shown that by useing an arctic soil as a seed we can treat wastewater at temperatures as low as 4 Celsius. By calculating specific rates we have been able to propose sizes for reactors. Furthermore we are able to show that lipolysis is the rate limiting step at low temperatures and that this is due to poor enzyme activity and not an absence of enzyme per se.
Exploitation Route We hope we will enable low energy anaerobic treatment systems to be introduced into temperate climates, potentially saving very large quantities of energy
Sectors Environment

URL http://www.ncl.ac.uk/ceg/staff/profile/tom.curtis
 
Description We have used the findings to design a pilot scale anaerobic treatment plant for treating domestic wastewater at ambient temperatures
First Year Of Impact 2014
Sector Environment
Impact Types Economic