Novel anaerobic biological treatment systems

Anaerobic treatment is an innovative method of treating wastewater, which results in energy production. Conventional anaerobic systems have been widely used to treat high-strength wastewater or sludge. Nowadays, novel anaerobic systems are also in use for low-strength wastewater for energy recovery purposes. There are several types of novel anaerobic treatment systems including membrane-based anaerobic reactors, anaerobic biofilm systems, hybrid fix-bed anaerobic reactors, anaerobic migrating blanket reactor, anaerobic baffled reactors, and anaerobic fluidized-bed reactors. Although the anaerobic forward osmosis (FO) membrane bioreactor (MBR) process is costly when it uses reverse osmosis discharge as a draw solution, it becomes energy self-sufficient when FO preconcentration is made. The viability of the quorum quenching (QQ) approach (anaerobic QQ MBR), which is a cost-effective and chemical-free way for reducing membrane fouling in aerobic MBRs, in anaerobic MBRs is still at an early stage. Anaerobic membrane distillation bioreactor and electrochemical MBRs are novel experiments with few references in the literature, and energy costs may be high. Hybrid fix-bed anaerobic reactor configurations have recently gained popularity due to significant benefits such as pathogen reduction, green energy generation, odor reduction, cost-effectiveness, high treatment reliability, and low sludge output. Energy recovery and circular economy are two major trends in membrane-based anaerobic reactors. Other than the membrane-based systems, there are also novel systems that integrate well without membrane use. The historical context and novel anaerobic biological treatment systems will be discussed in depth in this chapter.