藻类生长对好氧颗粒污泥的影响

Effect of Algae Growth on Performance of Aerobic Granular Sludge

在利用好氧颗粒污泥处理低C/N值模拟城市生活污水的优化运行过程中首次发现了藻类的存在。随着藻含量的升高,好氧颗粒污泥逐渐由黄色变为绿色,污泥絮体、破碎颗粒以及不规则大颗粒增多,导致其沉降性能下降,SVI由31.4 mL/g升高到54 mL/g。藻类的存在对好氧颗粒污泥降解有机物和除磷的影响不大,但使脱氮性能下降。对氨氮的平均去除率由94.3%下降到91.3%;出水硝态氮和亚硝态氮浓度升高;对总氮的平均去除率由83.4%下降到77.4%。脱氮性能的下降主要是由于藻类覆盖在好氧颗粒污泥表面后增大了传质阻力,对反硝化产生抑制作用。通过置换污泥、改变进水组分配比和减少光照均能起到除藻效果。其中,减少光照时间的除藻效果最快,但是易造成颗粒解体;改变进水组分配比的效果最慢也最差。

Algae were observed when using aerobic granular sludge to treat low C/N synthetic mu- nicipal sewage. As algae concentration increased, sludge color changed from yellow to green, and sludge floes, crushed granules and large irregular granules increased, which caused sludge settleability deteriora- tion and SVI raised from 31.4 mL/g to 54 mL/g. Algae covering the surface of aerobic granular sludge increased mass transfer resistance, which inhibited denitrification, but had little effect on COD and phos- phorus removal. The removal rates of NH4 - N and TN declined from 94.3% to 91.3% and from 83.4% to 77.4% , respectively, and the effluent concentrations of NO3- - N and NOr - N increased. Algae could be removed by replacing sludge, changing the distribution ratio of the influent ingredients and reducing lighting time. Reducing lighting time achieved the fastest algae removal but led to granule disintegration. Changing the distribution ratio of the influent ingredients led to the slowest and poorest al- gae removal.