Venkata Mohan S, Vijaya Bhaskar Y, Sarma P N
Indian Institute of Chemical Technology, Bioengineering and Environmental Centre, Tarnaka, Hyderabad 500007, India.
Water Res. 2007 Jun;41(12):2652-64. doi: 10.1016/j.watres.2007.02.015. Epub 2007 Apr 5.
Molecular hydrogen (H(2)) production with simultaneous wastewater treatment was studied in biofilm configured periodic discontinuous/sequencing batch reactor using chemical wastewater as substrate. Anaerobic mixed consortia was sequentially pretreated with repeated heat-shock (100 degrees C; 2 h) and acid (pH-3.0; 24 h) treatment procedures to selectively enrich the H(2) producing mixed consortia prior to inoculation of the reactor. The bioreactor was operated at mesophilic (room) temperature (28+/-2 degrees C) under acidophilic conditions with a total cycle period of 24 h consisting of FILL (15 min), REACT (23 h), SETTLE (30 min) and DECANT (15 min) phases. Reactor was initially operated with synthetic wastewater (SW) at OLR of 4.8 kg COD/m(3)-day and subsequently operated using composite chemical wastewater (CW) at OLR of 5.6 kg COD/m(3)-day by adjusting pH to 6.0 prior to feeding to inhibit the methanogenic activity. H(2) evolution rate differed significantly with the nature of wastewater used as substrate [SW--volumetric H(2) production rate--12.89 mmol H(2)/m(3)-min and specific H(2) production rate--0.0084 mmol H(2)/min-g COD(L) (0.026 mmol H(2)/min-g COD(R)); CW--volumetric H(2) production rate--6.076 mmol H(2)/m(3)-min and specific H(2) production rate--0.0089 mmol H(2)/min-g COD(L) (0.033 mmol H(2)/min-g COD(R))]. Relatively rapid progress towards higher H(2) yield (2 h) was observed with SW compared to the CW (10 h). Substrate (COD) reduction of 32.4% (substrate degradation rate (SDR)--1.55 kg COD/m(3)-day) and 26.7% (SDR-1.49 kg COD/m(3)-day) was observed with SW and CW, respectively. The system showed rapid stabilization tendency (SW--37 days; CW--40 days) with respect to H(2) generation and COD reduction. H(2) evolution showed relatively good correlation with VFA concentration in the case of SW (R(2)-0.961) compared to CW (R(2)-0.912). A surge in pH values from 5.87 to 4.23 (SW) and 5.93 to 4.62 (CW) was observed during the cycle operation. Integration of biofilm configuration with periodic discontinuous batch operation under the defined operating conditions showed potential to influence the microbial system by selectively enriching the specific group of microflora capable of producing H(2).
以化学废水为底物，在生物膜配置的周期性间断/序批式反应器中研究了同步废水处理过程中分子氢（H₂）的产生。厌氧混合菌群在接种反应器之前，依次经过重复热休克（100℃；2小时）和酸（pH值3.0；24小时）处理程序进行预处理，以选择性富集产氢混合菌群。生物反应器在嗜酸性条件下的中温（室温）（28±2℃）下运行，总循环周期为24小时，包括进水（15分钟）、反应（23小时）、沉淀（30分钟）和排水（15分钟）阶段。反应器最初使用合成废水（SW），有机负荷率为4.8 kg COD/m³·天，随后通过在进料前将pH值调节至6.0以抑制产甲烷活性，使用复合化学废水（CW），有机负荷率为5.6 kg COD/m³·天。氢气产生速率因用作底物的废水性质而有显著差异[SW——氢气体积产率——12.89 mmol H₂/m³·分钟，氢气比产率——0.0084 mmol H₂/分钟·g COD（L）（0.026 mmol H₂/分钟·g COD（R））；CW——氢气体积产率——6.076 mmol H₂/m³·分钟，氢气比产率——0.0089 mmol H₂/分钟·g COD（L）（0.033 mmol H₂/分钟·g COD（R））]。与CW（10小时）相比，SW在相对较短时间（2小时）内实现了更高的氢气产量。使用SW和CW时，底物（COD）去除率分别为32.4%（底物降解率（SDR）——1.55 kg COD/m³·天）和26.7%（SDR——1.49 kg COD/m³·天）。该系统在氢气产生和COD去除方面显示出快速稳定的趋势（SW——37天；CW——40天）。与CW（R²——0.912）相比，SW情况下氢气产生与挥发性脂肪酸（VFA）浓度的相关性相对较好（R²——0.961）。在循环运行期间，观察到pH值从5.87飙升至4.23（SW）和从5.93飙升至4.6（CW）。在规定的操作条件下，生物膜配置与周期性间断批式操作的结合显示出通过选择性富集能够产生氢气的特定微生物菌群来影响微生物系统的潜力。
