The Microbiology and Biochemistry of Anaerobic Bioreactors with Relevance to Domestic Sewage Treatment

Abstract

Anaerobic granular and fixed-film reactors have been successfully operated for wastewater treatment at full scale for over two decades and represent a sustainable, energy-producing approach, which is increasingly being directed towards treatment of domestic sewage. Research over the past two decades, and significant operational experience, has demonstrated that there are no fundamental microbiological barriers to the implementation of AD for domestic sewage treatment in regions with warm and temperate climates. Despite this, the underlying microbiology of methanogenesis is not fully understood and novel groups of microbes have been identified in sludge, with unknown functions. The methanogenic process has recently been subject to systematic investigation using newly developed analytical and microbiological approaches. A combination of process monitoring, physiological, molecular microbiological and microscopic methods are beginning to generate a comprehensive, integrated data set at micro-organism, granule and reactor level and the current state of knowledge is reviewed here. Information on the formation of granules, on the relationship between reactor operating conditions and microbial consortia and on the impact of process changes on the microorganisms in reactors will, in future, enable the link between the processes occurring at microorganism level (scale ca. 1 lm-1 mm) and the processes occurring within reactors (scale > 1 m), which will enhance the efficiency and applicability of anaerobic sewage treatment.

An Advanced Biosolids Treatment Process and Potential Beneficial Applications of the Processed Biosolids

“…This protects the environment from the uncontrolled degradation of the waste. Thus, it reduces the impacts from environmental aspects such as odour, flies and vermin and helps to reduce the plant and animal pathogens that can be spread by wastes (O'Flaherty et al, 2006). Co-disposal of this sludge at solid waste landfills is not a viable long-term alternative and the clear tendency in North America is to minimize the disposal of biodegradable wastes to landfills and promoting the options of recycling, composting, energy production and recovery.…”

Anaerobic digestion of vinasse from sugarcane ethanol production in Brazil: Challenges and perspectives

“…Anaerobic digestion consists of a set of complex and sequential metabolic processes that occur in the absence of molecular oxygen and depend on the activity of at least three distinct groups of microorganisms to promote the stable and self-regulating fermentation of organic matter, resulting mainly in methane and carbon dioxide gases [68][69][70][71]. These groups of microorganisms include acidogenic (or fermentative) bacteria, acetogenic (or syntrophic) bacteria, and methanogenic archaea [72][73][74].…”

Comparative Analysis of Bacterial and Archaeal Communities in Methanogenic Sludge Granules from Upflow Anaerobic Sludge Blanket Reactors Treating Various Food-Processing, High-Strength Organic Wastewaters

“…To date, various anaerobic processes for treating wastewater have been developed (1,29,32). One of the most established technologies in this field is the upflow anaerobic sludge blanket (UASB) system, because of its ability to treat a broad range of organic waste streams at high loading rates (32,40,45,47). The most characteristic phenomenon in this process is sludge granulation, i.e., granular-shaped sludge is spontaneously formed within the system.…”