COD reduction and decolorization of sweet sorghum distillery slops by sequential anaerobic digestion and preliminary electrooxidation

Date

4-2012

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Abstract

Chemical oxygen demand (COD) reduction and decolorization of sweet sorghum distillery effluent was investigated using anaerobic digestion followed by preliminary electrooxidation. Anaerobic digestion was conducted in order to investigate the effects of organic loading rates (OLR) in the anaerobic treatment of the wastewater. OLRs of 5.534mg COD/L-d (HRT=30d) and 2.7mg COD/L-d(HRT=60d) were used in the study under a semi-continuous mode of operation. The organic loading for the 30d HRT digester was considered to be too high for the proper functioning of an anaerobic digestion treatment system. The steady-state pH was acidic with no removal of COD. On the other hand, the digester with 60d HRT showed a stable digester operation. AS pH range of 6.87 to 8.42 was achieved which was in the range of optimum anaerobic digestion. The COD removal efficiency was 30.82%, and gas production was 1,819mL/day. A second stage treatment of 12-hr electrooxidation at 1.5A and 2.5% chloride supplementation resulted in further removal of 24% of COD and 41% of color. Increase in both temperature and pH were observed during the electrochemical treatment, but these eventually leveled-off to stable values. Charge dose for COD removal (a scale-up operating factor) was found to be 11.632 Coulombs/mg COD removed. The computed energy requirement was found to be 1.75x10⁻⁵ kWh/mg pollutant removed while the energy cost was PhP1,159.14/m³. The resulting effluent after anaerobic digestion and preliminary electrooxidation were not yet complaint with DENR Class C standards. Further studies are recommended to extend operation at 60d HRT ( anaerobic digestion) and to increase chloride supplementation or operating current in electrooxidation to improve DENR compliance.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2012 E62 P37

Document Type

Thesis

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