Effect of inhibition treatment, type of inocula, and incubation temperature on batch H2 production from organic solid waste

Abstract

Two types of induction treatments (heat-shock pretreatment, HSP, and acetylene, Ac), inocula (meso and thermophilic) and incubation temperatures (37 and 55 degrees C) were tested according to a full factorial design 2(3) with the aim of assessing their effects on cumulative H(2) production (P(H), mmol H(2)/mini-reactor), initial H(2) production rate (R(i,H), micromol H(2)/(g VS(i) x h)), lag time (T(lag), h), and metabolites distribution when fermenting organic solid waste with an undefined anerobic consortia in batch mini-reactors. Type of inocula did not have a significant effect on P(H), T(lag), and R(i,H) except for organic acids production: mini-reactors seeded with thermophilic inocula had the highest organic acid production. Concerning the induction treatment, it was found that on the average Ac only affected in a positive way the P(H) and T(lag). Thus, P(H) in Ac-inhibited units (6.97) was 20% larger than those in HSP-inhibited units (5.77). Also, Ac favored a shorter T(lag) for P(H) in comparison with HSP (180 vs. 366). Additionally, a positive correlation was found between H(2) and organic acid production. In contrast, solvent concentration in heat-shocked mini-reactors were slightly higher than in reactors spiked with Ac. Regarding the incubation temperature, on the average mesophilic temperature affected in a positive and very significant way P(H) (10.07 vs. 2.67) and R(i,H) (2.43 vs. 0.76) with minimum T(lag) (87 vs. 459). The positive correlation between H(2) and organic acids production was found again. Yet, incubation temperature did not seem to affect solvent production. A strong interaction was observed between induction treatment and incubation temperature. Thus, Ac-inhibited units showed higher values of P(H) and R(i,H) than that HSP-inhibited units only under thermophilic incubation. Contrary to this, HSP-inhibited units showed the highest values of P(H) and R(i,H) only under mesophilic conditions. Therefore, the superiority of an induction treatment seems to strongly depend on the incubation temperature.

Effect of Methanogenic Inhibitors, Inocula Type, and Temperature on Biohydrogen Production From Food Components

“…The largest average difference in lag time (~ 66 hours) was observed for S at thermophilic temperatures. Previous studies have also indicated that heat treatment can be detrimental to hydrogen production when compared to other methods (Cheong and Hansen, 2006;Valdez-Vazquez et al, 2006;Zhu and Béland, 2006). G and S also showed significant differences for the effects of temperature.…”

“…Biohydrogen production from municipal solid waste has been well studied (Lay et al, 1999;Liu et al, 2006;Ueno et al, 2007;Valdez-Vazquez et al, 2005;Valdez-Vazquez et al, 2006). Even though municipal solid waste is comprised of 20-65% kitchen waste (Tchobanoglous et al, 1993), there have only been a few studies concerning hydrogen production from food waste.…”

“…Previous studies carried out with other substrates have shown that the different methods to inhibit methanogens can affect hydrogen production (Cheong and Hansen, 2006;Kraemer and Bagley, 2007;Oh et al, 2003;Valdez-Vazquez et al, 2006;Zhu and Béland, 2006). In addition, different inocula "Gh.…”

“…In addition, different inocula "Gh. Asachi" Technical University of Iasi, Romania sources and temperature can affect the amount of hydrogen produced (Danko et al, 2008;Lay et al, 1999;Li and Fang, 2007;Lin et al, 2006;Shin et al, 2004;Valdez-Vazquez et al, 2006;Van Ginkel et al, 2001;Yu et al, 2002).…”

“…Several studies have shown that hydrogen yields and rates increase as the temperature increases (Lin and Chang 2004;Morimoto et al, 2004;Valdez-Vazquez et al, 2005;Yu et al, 2002). However, increasing temperature can also have detrimental effects on hydrogen production and rates Valdez-Vazquez et al 2006). Lin et al (2008) showed that even increases of just 5 ºC can impact hydrogen production and rates by as much as 25% .…”