Anaerobic digestion process pretreatments

Pretreatments of the polymeric feedstocks to enhance the hydrolysis of the major components such as cellulose include size reduction, thermal-chemical treatments, and specific enzyme pretreatments (52,57). Although many of the pretreatment processes increase the rate and extent of potymer hydrolysis, the cost for treatment is prohibitive based upon the revenues generated for energy production alone in anaerobic digestion (32). 

The anaerobic biological conversion of the major polymeric components of MSW identified require appropriate microorganisms and hydrolytic enzyme systems. Extracellular hydrolytic enzymes, such as cellulases and lipases, have been shown to be effective in the post hydrolysis of anaerobic digester efQuent solids 34) or pretreatment of complex organic polymers before the digestion process 48),... 

In addition to the effluent limitations and the processes shown in Table 24 the degree of reduction in heavy metals waste loadings should consider the sludge handling and disposal methods used for the metal finishing wastewaters. Some processes (e.g., anaerobic digestion) concentrate these metals, and this can lead to process failure unless adequate pretreatment is provided. Dewatering operations discussed in Chapter 7 should be referred to. 

Anaerobic digestion can partially break down some halogenated organics unsuitable for aerobic digestion. Also, anaerobic systems can be used as a pretreatment step prior to aerobic biodegradation. Recommended influent characteristics for anaerobic processes are as follows ... 

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