Impact of pH Management Interval on Biohydrogen Production from Organic Fraction of Municipal Solid Wastes by Mesophilic Thermophilic Anaerobic Codigestion.

Chaudhry Arslan,Muhammad Zia Bakht,Asma Sattar,Ji Changying,Irshad Ali Mari,Abdul Nasir

doi:10.1155/2015/590753

Abstract

The biohydrogen productions from the organic fraction of municipal solid wastes (OFMSW) were studied under pH management intervals of 12 h (PM12) and 24 h (PM24) for temperature of 37 ± 0.1°C and 55 ± 0.1°C. The OFMSW or food waste (FW) along with its two components, noodle waste (NW) and rice waste (RW), was codigested with sludge to estimate the potential of biohydrogen production. The biohydrogen production was higher in all reactors under PM12 as compared to PM24. The drop in pH from 7 to 5.3 was observed to be appropriate for biohydrogen production via mesophilic codigestion of noodle waste with the highest biohydrogen yield of 145.93 mL/g CODremoved under PM12. When the temperature was increased from 37°C to 55°C and pH management interval was reduced from 24 h to 12 h, the biohydrogen yields were also changed from 39.21 mL/g CODremoved to 89.67 mL/g CODremoved, 91.77 mL/g CODremoved to 145.93 mL/g CODremoved, and 15.36 mL/g CODremoved to 117.62 mL/g CODremoved for FW, NW, and RW, respectively. The drop in pH and VFA production was better controlled under PM12 as compared to PM24. Overall, PM12 was found to be an effective mean for biohydrogen production through anaerobic digestion of food waste.

Highlights

Anaerobic digestion is in practice for more than a century and from the last two decades, it has been used for biological hydrogen production [1]
The biohydrogen production in rice waste (RW) reactors was not affected by the increase in temperature, but the production started after 12 hours of incubation as compared to noodle waste (NW) where it started during 12 hours of incubation
The impact of pH management interval on biohydrogen production can be observed in Figure 3, where the differences in biohydrogen production under both pH managements were drawn on 12-hourly basis

Summary

Introduction

Anaerobic digestion is in practice for more than a century and from the last two decades, it has been used for biological hydrogen production [1]. Hydrogen produced by biological means, such as dark fermentation and photofermentation, is not enough to meet the demands, as the processes are not too efficient. Apart from the yield, mix consortia of Clostridium that can survive better under a wide range of environmental conditions are used as hydrogen producers in dark fermentation [6]. Clostridium is Gram-positive and spore-forming anaerobic bacteria and mix consortia of Clostridium are available in the form of sludge, which makes it a suitable economical inoculum for hydrogen production [7]. Sludge contains hydrogen consumers, that is, methanogens, that cannot survive at higher temperature, whereas Clostridium can survive by forming protective spores [8]. Keeping in view the spore forming property of Clostridium under high temperature, heat treatment in an oven is widely opted to deactivate methanogens due to easy operation and availability [9]

Methods

Results

Conclusion