Comparison of ASBR and CSTR reactor for hydrogen production from palm oil mill effluent under thermophilic condition

Jiravut Seengenyoung,Sompong O-Thong,Poonsuk Prasertsan

doi:10.4236/abb.2014.53022

Jiravut Seengenyoung, Sompong O-Thong + Show 1 more

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https://doi.org/10.4236/abb.2014.53022

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Abstract

Hydrogen production from palm oil mill effluent (POME) by Thermoanaerobacterium thermosaccharolyticum PSU-2 was investigated both in batch and continuous reactors using anaerobic sequencing batch reactor (ASBR) and continuous stirred tank reactor (CSTR). The hydrogen production determined from batch experiment of POME at an inoculum size of 0%, 10%, 20% and 30% (v/v) was 161, 201, 246 and 296 mL H2/g-COD with COD removal efficiency of 21%, 23%, 23% and 23%, respectively. Continuous hydrogen production was start-up with 30% (v/v) inoculum in both ASBR and CSTR reactors and more than 30% COD removal could be obtained at HRT of 4 days, corresponding to OLR of 11.3 g COD/ L·day. Similar hydrogen production rates of 2.05 and2.16 LH2/L. day were obtained from ASBR and CSTR, respectively. COD removal efficiency of ASBR was 37.7%, while it was 44.8% for CSTR. However, ASBR was stable in term of alkalinity, while the CSTR was stable in term of hydrogen production, soluble metabolites concentration and alkalinity. Therefore, the CSTR was found to be more stable in hydrogen production than ASBR under the same OLR.

Highlights

Hydrogen (H2) is a clean and promising fuel when it is derived from renewable energy sources
Hydrogen production from palm oil mill effluent (POME) by Thermoanaerobacterium thermosaccharolyticum PSU-2 was investigated both in batch and continuous reactors using anaerobic sequencing batch reactor (ASBR) and continuous stirred tank reactor (CSTR)
Continuous hydrogen production was start-up with 30% (v/v) inoculum in both ASBR and CSTR reactors and more than 30% Chemical oxygen demand (COD) removal could be obtained at HRT of 4 days, corresponding to OLR of 11.3 g COD/ L·day

Summary

Introduction

Hydrogen (H2) is a clean and promising fuel when it is derived from renewable energy sources. It has high energy content, and water is the sole end product after combustion [1]. Hydrogen production by microorganisms can be divided into two main categories: one involves the use of photosynthetic bacteria and algae under light condition and the other, anaerobic fermentative bacteria under dark condition. A strict anaerobic thermophilic bacterial strain with high production rate and yield of H2, named Thermoanaerobacterium thermosaccharolyticum PSU-2, was isolated from palm oil mill effluent (POME) by O-Thong et al [1]. The use of pure cultures in dark fermentation of carbohydrates for hydrogen production is expensive and technically difficult requiring sterile conditions

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