Anaerobic reduction, effluents

Purification of effluents with high organic content takes place in two main steps anaerobic reduction and aerobic oxidation causing mineralization of the organic products. Azo... 

Most often, the rates for feedstock destruction in anaerobic digestion systems are based upon biogas production or reduction of total solids (TS) or volatile solids (VS) added to the system. Available data for analyses conducted on the specific polymers in the anaerobic digester feed are summarized in Table II. The information indicates a rapid rate of hydrolysis for hemicellulose and lipids. The rates and extent of cellulose degradation vary dramatically and are different with respect to the MSW feedstock based on the source and processing of the paper and cardboard products (42). Rates for protein hydrolysis are particularly difficult to accurately determine due the biotransformation of feed protein into microbial biomass, which is representative of protein in the effluent of the anaerobic digestion system. 

The two stages aerobic treatment was obtained not by-passing the smaller aeration tank D (h = 0.3 m, 0 = 0.16 m, V = 4 1) equipped with internal sedimentation. In some cases nutrients were supplied to the system as (NH4)2S04 and K2HPO4. The anaerobic effluent was conveyed to the aerobic treatment only after > 50% COD reduction was attained in the UASB reactor. This required approx. 2 months from the UASB start-up. 20-40 more days were then required before steady state was attained in the aerobic treatment, so that each series of runs performed according to the flow-sheet in Fig. 1 lasted approx. 4 months, for an over-all duration of this study of approx. 12 months. 

---