2011•Unpublished venueRequires access
Comparative evaluation of high rate anaerobic processes for treatment of distillery spent wash
Grandhi S Chandragupta, Lopa Mudra, Sunil Kumar Gupta, Surendra Singh
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Abstract
The efficiency of anaerobic biodegradation of wastewater can be enhanced by controlling several factors, such as pH, influent substrate concentration, solid retention time (SRT), flow pattern, HRT, organic loading rate etc. The present study describes the performance efficiency of two high rates anaerobic processes i.e., upflow anaerobic sludge blanket (UASB) reactor and anaerobic hybrid reactor incorporating the dual advantages of suspended growth as well as attached growth system using distillery spent wash as a substrate. Start-up study demonstrated that an early start-up can be achieved in hybrid reactor (40 days) than in UASB reactor (50 days). The granulation also was first observed in hybrid reactor (45 days) than in UASB reactor (60 days). In terms of process performance, optimum COD removal efficiency and methane yield, the hybrid reactor was found approximately 5 % more than the UASB reactor. Higher COD removal and biogas production in hybrid reactor can be attributed to higher sludge retention (75-989 days) compared to the UASB reactor (67-511 days). For a distillery plant of 30 KLD, hybrid reactor can result in an additional COD reduction of 1,913 kg and produce 759m 3 more methane per day than UASB reactor. An energy audit of the biogas generation has revealed that an additional energy saving of 15, 939 MJ/day can be achieved by using hybrid reactor technology than UASB reactor for a distillery plant of 30 KLD. Sudden washout of the sludge which is a serious drawback associated with suspended growth system (UASB reactor) can considerably be reduced (25%) in hybrid reactor. Shock loading study demonstrated that hybrid reactor is capable of resisting up to 2 times of continuous shock loading while the UASB reactor could withstand only 1.5 times of continuous shock loading. The study revealed that the plug flow regime of hybrid reactor makes it more competitive and efficient than completely mixed flow regime observed in UASB reactor.