Optimizing the impact of temperature on bio-hydrogen production from food waste and its derivatives under no pH control using statistical modelling

Abstract

Abstract. The effect of temperature on bio-hydrogen production by co-digestion of sewerage sludge with food waste and its two derivatives, i.e. noodle waste and rice waste, was investigated by statistical modelling. Experimental results showed that increasing temperature from mesophilic (37 • C) to thermophilic (55 • C) was an effective mean for increasing bio-hydrogen production from food waste and noodle waste, but it caused a negative impact on bio-hydrogen production from rice waste. The maximum cumulative biohydrogen production of 650 mL was obtained from noodle waste under thermophilic temperature condition. Most of the production was observed during the first 48 h of incubation, which continued until 72 h of incubation. The decline in pH during this interval was 4.3 and 4.4 from a starting value of 7 under mesophilic and thermophilic conditions, respectively. Most of the glucose consumption was also observed during 72 h of incubation and the maximum consumption was observed during the first 24 h, which was the same duration where the maximum pH drop occurred. The maximum hydrogen yields of 82.47 mL VS −1 , 131.38 mL COD −1 , and 44.90 mL glucose −1 were obtained from thermophilic food waste, thermophilic noodle waste and mesophilic rice waste, respectively. The production of volatile fatty acids increased with an increase in time and temperature in food waste and noodle waste reactors whereas they decreased with temperature in rice waste reactors. The statistical modelling returned good results with high values of coefficient of determination (R 2 ) for each waste type and 3-D response surface plots developed by using models developed. These plots developed a better understanding regarding the impact of temperature and incubation time on bio-hydrogen production trend, glucose consumption during incubation and volatile fatty acids production.

Comparing the Bio-Hydrogen Production Potential of Pretreated Rice Straw Co-Digested with Seeded Sludge Using an Anaerobic Bioreactor under Mesophilic Thermophilic Conditions

“…For the same duration, the VFA production was not so high in the thermophilic reactor under the same treatment, but bio-hydrogen production was much higher in the thermophilic reactor. The higher VFA contents can be inhibitory to the growth of bacteria, as they cause unfavorable physical changes in the cell and excessive energy is required to pump ions [25]. Such high energy is available at elevated temperatures, which increased the yield at elevated temperatures, as observed in the present study [47][48][49].…”

“…The volume of hydrogen gas was measured in the same way opted in our previous studies [24,25,27]. The compositional properties of straw were measured by the procedure opted by Ververis [28].…”

“…There was an inlet port (1-inch diameter) for feeding materials at the top, and an outlet port (1-inch diameter) along with a ball valve was at the bottom. A vacuum pump (FY-1H-N, Zhejiang E & M Value Co.: Zhejiang, China) was also attached to the reactor to develop anaerobic conditions [24,25]. …”

Simultaneous bio‐electricity and bio‐hydrogen production in a continuous flow single microbial electrochemical reactor

“…Regarding hydrogen generation, bacteria are widely used as inoculum in pure or co‐culture. Several of the hydrogen‐producing bacteria are strict anaerobes and facultative anaerobes . In anaerobic environments, protons recombine with the electrons through the catalysis of the hydrogenase enzyme for the production of hydrogen .…”

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

“…The biohydrogen production volume was measured by connecting each reactor with a measuring bottle containing 3% NaOH solution that could remove other gases and water vapors. The volume of NaOH displaced out was measured by measuring cylinder as a volume of biohydrogen produced in mL [ 37 – 39 ]. The total solids (TS), volatile solids (VS), chemical oxygen demand (COD), and volatile fatty acids (VFA) were measured according to standard methods [ 40 ].…”