Department of Agricultural Engineering, Faculty of Agriculture, Mansoura University, P.O. Box 46, El-Mansoura, Egypt.
Bioresour Technol. 2010 Jun;101(11):4021-8. doi: 10.1016/j.biortech.2010.01.027. Epub 2010 Feb 4.
The effect of manure-screening on the biogas yield of dairy manure was evaluated in batch digesters under mesophilic conditions (35 degrees C). Moreover, the study determined the biogas production potential of different mixtures of unscreened dairy manure and food waste and compared them with the yield from manure or food waste alone. A first-order kinetics model was developed to calculate the methane yield from different mixtures of food waste and unscreened dairy manure. The methane yields of fine and coarse fractions of screened manure and unscreened manure after 30days were 302, 228, and 241L/kgVS, respectively. Approximately 93%, 87%, and 90% of the biogas yields could be obtained, respectively, after 20days of digestion. Average methane content of the biogas was 69%, 57%, and 66%, respectively. Based on mass balance calculations, separation of the coarse fraction of manure would sacrifice about 32% of the energy potential. The methane yield of the food waste was 353L/kgVS after 30days of digestion. Two mixtures of unscreened manure and food waste, 68/32% and 52/48%, produced methane yields of 282 and 311L/kgVS, respectively after 30days of digestion. After 20days, approximately 90% and 95% of the final biogas yield could be obtained, respectively. Therefore, a hydraulic retention time (HRT) of 20days could be recommended for a continuous digester. The average methane content was 62% and 59% for the first and second mixtures, respectively. The predicted results from the model showed that adding the food waste into a manure digester at levels up to 60% of the initial volatile solids significantly increased the methane yield for 20days of digestion.
在中温条件（35°C）下，分批消化器中评估了粪便筛选对奶牛粪便沼气产量的影响。此外，本研究确定了不同未筛选的奶牛粪便和食物废物混合物的沼气产生潜力，并将其与单独使用粪便或食物废物的产量进行了比较。建立了一阶动力学模型来计算不同未筛选的奶牛粪便和食物废物混合物的甲烷产量。经过 30 天，筛选后的精细和粗糙肥料部分的甲烷产量分别为 302、228 和 241L/kgVS。消化 20 天后，分别可以获得约 93%、87%和 90%的沼气产量。沼气中甲烷的平均含量分别为 69%、57%和 66%。基于质量平衡计算，分离肥料的粗粒部分会牺牲约 32%的能量潜力。经过 30 天的消化，食物废物的甲烷产量为 353L/kgVS。两种未筛选的粪便和食物废物混合物，68/32%和 52/48%，分别在 30 天的消化后产生 282 和 311L/kgVS 的甲烷产量。消化 20 天后，分别可以获得约 90%和 95%的最终沼气产量。因此，对于连续消化器，建议水力停留时间（HRT）为 20 天。两种混合物的平均甲烷含量分别为 62%和 59%。模型的预测结果表明，将食物废物以高达初始挥发性固体 60%的比例添加到粪便消化器中，可显著提高 20 天的消化甲烷产量。
