低浓度生活污水自由沉降规律及其对厌氧发酵的影响

Free Sedimentation Regulation of Low Concentration Domestic Sewage and Its Effect on Anaerobic Fermentation

文章研究了低浓度生活污水自由沉淀规律及其对厌氧发酵的影响,以高校低浓度生活污水为原料,通过测定不同取样口不同时间水样中悬浮物浓度的变化,根据斯托克斯原理计算不同取样口不同时间水样悬浮物沉淀率,以自由沉降的预处理方法分析低浓度生活污水的沉淀规律和不同沉降层的发酵规律。试验结果表明,随着时间增长,取样口1#处水样悬浮浓度随时间先增加后逐渐变小,其他取样口处水样悬浮物浓度随时间逐渐变小,取样口高度越高悬浮物浓度变化越快,150 min后均趋于稳定;不同高度取样口浓度随时间变化规律不同,取样口水平高度越高水样悬浮物浓度变化越快;同一取样口水样悬浮物沉淀率随时间逐渐变大,同一时间取样口越高的悬浮物沉淀率越大,150 min后沉淀效果最佳且趋于稳定,水样悬浮物沉淀率达到70%左右;厌氧发酵试验中,中层混合物和下层沉降物的发酵产气能力较强,最高产气量均可达到每天3000 m L,甲烷含量可以达到60%;上清液由于含水率大,有机物成分较少,产气能力较弱。

This paper studied the regulation of free sedimentation of low concentration domestic sewage and the effect on anaerobic fermentation taking low concentration domestic sewage from a university campus as raw material. Samples were taken from different sample connections at different time,the suspended solid concentrations of samples were determined and the sedimentation rate was calculated based on the principle of Stokes. The free sedimentation regulation of low concentration domestic sewage and the anaerobic fermentation characteristics of different sedimentation layer were analyzed. The results showed that,the suspended solids concentration gradually decreased with the time went on except the water sample from the 1# sample connection that there was an increase firstly and then gradually decrease. The higher the sample connection location,the faster the suspended solids concentration changed,and the higher the sedimentation rate. After 150 min,the sedimentation tended to be stable and so the suspended soli concentration. The sedimentation rate was about 70% during the stable period. The mixture in the middle layer and the sediment in the lower layer had the better biogas production ability with the highest gas production of 3000 m L·d-1and methane content of 60%. The supernatant liquid had few organic matter,and so very low biogas production ability.