鲜水葫芦与其汁液厌氧发酵产沼气效率比较

为开发高效处理水葫芦的厌氧发酵产沼气技术,该文在35℃中温条件下,分别以鲜水葫芦和经固液分离的水葫芦汁为发酵底物,应用实验室自行设计的2套完全混合搅拌反应器(CSTR)进行了厌氧发酵比较研究。结果表明,以水葫芦为底物直接进行厌氧发酵,最大容积负荷为2.0kg/(m3·d),挥发性固体(VS)产气率为267mL/g,容积产气率为0.61m3/(m3·d),滞留期为27d,平均甲烷体积分数为58%,而以水葫芦汁为底物,COD(化学需氧量)容积负荷可达6.0kg/(m3·d),原料(COD)产气率为231mL/g,容积产气率可达1.4m3/(m3·d),平均甲烷体积分数为66%,滞留期仅需2.4d,COD平均去除率达85%,MLVSS(挥发性悬浮物浓度)平均去除率可达88%。因此,对水葫芦进行固液分离,以水葫芦汁作为厌氧发酵原料可大大提高处理效率,为水葫芦资源化利用提供了一条新途径。

Comparison of biogas production efficiency of anaerobic digestion using water hyacinth and its juice from solid-liquid separation as feedstock

To exploit efficient technology of anaerobic digestion with water hyacinth, a laboratory experiment was carried out to assess the performance of water hyacinth and its juice from solid-liquid separation as feedstock in two continuous stirred-tank reactors (CSTR) at 35℃. Results showed that when using water hyacinth as feedstock for anaerobic digestion, the suitable organic loading rate (OLR) were 2.0 kg/(m3·d) with 27 d hydraulic retention time (HRT), and the relevant biogas production rate of volatile solid and the volume biogas yield were achieved at 267 mL/g and 0.61 m3/(m3·d) with 58% average methane content, respectively. Comparatively, using the juice of water hyacinth as feedstock for anaerobic digestion, the biogas production rate of chemical oxygen demand (COD) and OLR were 6 kg/(m3·d) and 1.4 m3/(m3·d), respectively, in which average methane content was 66%. Meanwhile, its HRT was reduced to 2.4 d. The reduction of COD and mixed liquor volatile suspended solids (MLVSS) were over 85% and 88%, respectively. Therefore, the juice of water hyacinth as feedstock for anaerobic digestion had higher utilization efficiency compared with water hyacinth itself, and consequently a new method for utilization of water hyacinth with less investment could be exploited.