Sequential Production Of Hydrogen And Methane From High Concentration Of Organic Wastewater Via Aaerobic Fermentation

Biohydrogen production technology made use of high concentration organic wastewater and other biomasses to produce hydrogen. Organic materials in organic wastewater were decomposed by hydrogen-producing bacteria into organic acids (acetic acid, butyric acid, etc.), ethanol, CO2 and H2. If the hydrogen bioproduction process and methane production process were combined, It will raise the raw material utilization ratio maximum ,but also provide the opportunity to reveal the relationship of microorganism in the stages of anaerobic digest.In this study, granular sludge was used as the inoculation sludge. Different pre-treatment methods of the granular sludge was done to suppress the production of methane and stop the process at ethanoic acid stage. Experiment regarding the fermentation of granular sludge with synthetic glucose wastewater was also done to see test its capability to produce hydrogen. Initial pH, fermentation temperature, carbon nitrogen ratio as well as the metal ions on hydrogen content and the accumulation gas production were also investigated in the experiment. Inoculation of the granular sludge, without pretreatment in hydrogen fermentation fluid, the methane bacteria carry on methane production process using hydrogen fermentation fluid. The optimum conditions of bioproduction of hydrogen and methane was investigated through the batch experiment. Meaningful results were obtained in comparison with independent methane bioproduction.The experimental result indication: 1. Comparing the four different kinds of pretreatment methods, the amount of gas and hydrogen content using granular sludge are: microwave treatment > alkali treatment >heat treatment > chloroform treatment > raw sewage.2. The best pretreatment method of the granular sludge to produce hydrogen is by microwave processing. At microwave process time 5min, gas volume and hydrogen content are 118 mL/g?glucose and 39.80% respectively. Though, there is a drop in the production of gas of raw sewage control group, but there is a significant increase in hydrogen production, 14.5 times of the raw sewage control group Fermentation fluid COD of 6605.4 mg/L, with elimination rate of 37.05%, is advantageous in research of methane production process.3. The optimum conditions for hydrogen production using granular sludge are pH 5.5, inoculate 150g of granular sludge together with 500ml of waste water, temperature kept at 35 degree and COD:N:P is 200:5:1 in waste water.4. The sequential bioproduction of hydrogen and methane produces 2.36 times more methane than independent methane production alone. Also, the effective components is 14% higher as compared to independent methane production.5. Metal ions plays a critical role on both hydrogen and methane production. The ideal concentration on hydrogen production are Fe2+ 0.50 mg/L, Ni2+ 1.0 mg/L and Mg2+ 0.50 mg/L. Metal ions affecting methane production is in the following order: Fe> Co> Ni.