黄花和脱水污泥厌氧消化的温室气体减排研究

采用联合国政府间气候委员会(IPCC)推荐的方法,对植物加拿大一枝黄花和污泥生物质厌氧消化产沼气的环境和能量影响进行了评估.环境影响评估重点关注温室气体(GHG)减排,将加拿大一枝黄花和脱水污泥的中温小试厌氧消化的甲烷产率数据运用于GHG减排潜质的计算;能量评估包括污泥贮存及传播、消化液的沼气逃逸,及化学肥料和化学药剂的投加几个过程中的直接和间接的能量输入.结果表明,一枝黄花和脱水污泥联合厌氧消化净GHG排放量随着SRT的缩短和黄花添加比例的增加而逐渐下降,在二者以挥发性固体(VS)比例1:1混合,停留时间为20d时的能量效率较高,GHG减排量较大,与基础方案相比,添加黄花可以实现78%的净GHG减排.

The greenhouse gases emissions reduction of anerobic digestion of solidago and dewatered sludge

According to the methodology by Intergovernmental Panel on Climate Change (IPCC), environmental and energetic impact of biogas production from the biomass composed of plant solidago canadensis L.(SC) and sewage sludge was evaluated in the study. Environmental evaluation focused on greenhouse gas (GHG) reduction, which was estimated from the methane yield through lab-scale anaerobic co-digestion of high-solid dewatered sludge (DS) and un-pretreated SC feedstocks with different volatile solid (VS) ratio of SC at mesophilic temperature. While energetic evaluation took into account the direct and indirect energy inputs of sludge storage and spreading, escaping of biogas from the digested effluent, and the addition of chemical fertilizers and reagents. These results indicated that anaerobic co-digestion of SC and DS to produce biogas was a high energy-efficient and environmentally friendly process. The net GHG emissions decreased with shortened SRT and increased portion of SC in the feedstock, and co-digestion of SC and DS at SRT of 20d with 50% VS addition of SC showed higher energy efficiency and significantly GHG reduction. Compared with the case with no SC, the addition of SC in the anaerobic digestion could achieve about 78 % reduction of net GHG emission. Besides, biogas plant operation was the largest energy consuming unit, in which stirring accounted for 39.5%~42.9% of the entire energy consumption of anaerobic digestion.