Yuan Zhenhong

Semi-dry mesophilic anaerobic digestion of water sorted organic fraction of municipal solid waste (WS-OFMSW).

An innovative municipal solid waste separation technology - water separation was developed in China recently. The purpose of this study was to evaluate the feasibility of anaerobic digestion from water sorted organic fraction of municipal solid waste (WS-OFMSW) to methane. A group of bench-scale (35 L) mesophilic (30 + or - 2 degrees Celsius) batch anaerobic digestions were carried out with three total solids in reactor (TSr = 16.0%, 13.5% and 11.0%). The biodegradability of WS-OFMSW with VS/TS of 61.6% was better than that of mechanically sorted OFMSW but still poor than that of source sorted OFMSW. No inhibitions of metal ions, volatile fatty acids and ammonia on anaerobic digestion were found. The reactors with TSr 16.0%, 13.5% and 11.0% achieved methane yield of 273, 283 and 314 L/kgVS and VS removal rate of 26.1%, 35.8% and 41.8%, respectively. The average methane content in biogas was about 66% for all reactors.

Low-cost additive improved silage quality and anaerobic digestion performance of napiergrass

Effects of molasses-alcoholic wastewater on the ensiling quality of napiergrass were investigated at ambient temperature, and its anaerobic digestion performance was assessed at mesophilic temperature. Results showed that the molasses-alcoholic wastewater had positive effect on silage quality and anaerobic digestion performance. Lower pH values of 5.20-5.28, lower NH3-N contents of 32.65-36.60 g/kg and higher lactic acid contents of 56-61 mg/kg FM were obtained for the silage samples with molasses-alcoholic wastewater addition. Higher specific biogas yield of 273 mL/g VS was obtained for the sample with 11% molasses-alcoholic wastewater added. Therefore 11% molasses-alcoholic wastewater addition was recommended.

Improving methane production from anaerobic digestion of Pennisetum Hybrid by alkaline pretreatment

Alkaline pretreatment with NaOH was used to improve methane yield from Pennisetum Hybrid. The pretreatments were carried out with different NaOH solutions (2-8% w/w) at three temperatures (35, 55 and 121 °C) for different periods of time (24, 24 and 1 h). All treated and untreated Pennisetum Hybrid were digested under mesophilic conditions (37 °C) to biogas, significant effects of the pretreatments on the yield of methane were observed. Results showed the modified Gompertz equation was reliable (determination coefficients (R2) greater than 0.96) to describe the kinetic behavior of anaerobic digestion of Pennisetum Hybrid. The best result, obtained by the treatment at 35 °C 2% NaOH for 24 h, resulted in the methane yield of 301.7 mL/g VS, corresponding to 21.0% improvement in the methane yield. Compositional, SEM, XRD and FTIR analysis confirmed that lignin removal, structural modification and cellulose crystalline variation were responsible for the improvement.

Performance of microbial fuel cell in different anode and cathode electrode sizes

Power generation in microbial fuel cell (MFC) at different cathode electrode surface area was examined in two-chambered system with sodium acetate as carbon sources. When the anode surface area of 66 cm² was used, the maximum power density increased by 44% when the cathode surface areas were increased from 66 cm² to 336 cm² and decreased by 21% when the cathode surface area was reduced to 14 cm², primarily as a result of the variation of cathode potential. The power increased from 2.56 W/m³ to 3.29 W/m³ with the cathode increasing from 14 cm² to 336 cm² when the anode surface area of 14 cm² was used. But a decreased power output of 2.40 W/m³ was observed when the relative electrode area of cathode and anode was 5AAn=Acat, the main reason may be the decreased in both anode and cathode potential. The low CE was in the range from 10 % to 15 % was obtained.

Evaluation of Fuel Ethanol Application in China

Through the analysis of the critical situation of liquid fuel and environment pollution in China, the developing status of fuel ethanol, which is the most direct and efficient way to lessen the oil consumption, are presented. For the fuel ethanol can solve oil shortage and environment pollution, Chinese government has given more attention to its development and it has tremendous market in China. Based on the situation of China, the fuel ethanol materials are evaluated. Finally the economy efficiency of different materials was invested. It is found out that the energy crops of sweet sorghum and cassava have economy predominance.