High-rate anaerobic wastewater treatment under psychrophilic and thermophilic conditions

Abstract

Anaerobic wastewater treatment is an attractive and generally accepted technology for the treatment of various types of medium- and high-strength wastewaters. So far, this treatment technology is mostly applied at the mesophilic temperature range between 25 and 40°C. However, results of recent research conducted under both psychrophilic (< 20°C) and thermophilic (> 45°C) conditions, reveal that temperature is not a limiting factor in applying anaerobic treatment, provided the appropriate process design is chosen. Temperature has a considerable impact on various biological and physical factors of the anaerobic conversion process. For instance, the biogas production rate is reduced to a minimum at low temperatures, while it can reach extreme values under thermophilic conditions. In sludge bed systems, the biogas production rate determines the degree of mixing between the biomass and the wastewater and should, therefore, be considered in the process design. Other impacts of temperature are related to inhibition effects under thermophilic conditions and to a non-desirable accumulation of non- or partly degradable organic matter under psychrophilic conditions. Obviously, these effects may hamper the utility of the commonly applied single stage reactor systems. However, by adapting the process design to the expected prevailing conditions inside the reactor, the loading potentials and overall stability of the anaerobic high-rate process may be distinctly improved.

Microbial community structure in a thermophilic anaerobic hybrid reactor degrading terephthalate

“…This is because PTA wastewater is usually generated at 54-60 u C, a temperature close to the optimum for thermophilic methanogenic consortia. Moreover, such consortia are reported to generally have much higher specific organic removal rates than the mesophilic consortia (van Lier et al, 1997). Thus, the anaerobic reactor volume required to treat a certain wastewater flow rate can be significantly smaller under thermophilic rather than mesophilic conditions.…”

Multiple syntrophic interactions in a terephthalate-degrading methanogenic consortium

“…This wastewater is generally treated by anaerobic biological processes under mesophilic conditions (B35 1C). However, anaerobic processes operated at hyper-mesophilic (46-50 1C) and thermophilic (B55 1C) temperatures may be preferable because of the ability to achieve higher loading rate (van Lier et al, 1997;Chen et al, 2004), which reduces the reactor volume. Moreover, TA wastewater is usually generated at 54-60 1C, and does not require additional energy input for maintaining reactor temperature (Chen et al, 2004).…”

Identification and Isolation of Anaerobic, Syntrophic Phthalate Isomer-Degrading Microbes from Methanogenic Sludges Treating Wastewater from Terephthalate Manufacturing

“…A number of anaerobic processes have been intensively developed over the past decades (31), and applications of these processes are now expanding to low-strength wastewaters (19), to wastes and wastewaters under extreme temperature conditions (16,19,35), and to more complex wastewaters containing anthropogenic compounds and/or compounds recalcitrant to biodegradation (22). Wastewaters with high concentrations of phthalate isomers (ortho-, meta-, and para-benzene dicarboxylic acid) are one of the complex wastewaters now being challenged by anaerobic processes.…”