不同活性污泥中污泥质量浓度对沉降性的影响

为了考察污泥质量浓度对活性污泥沉降性的影响,采用100 mL量筒进行批沉降试验,分别研究了不膨胀污泥、丝状菌膨胀污泥和非丝状菌膨胀污泥在不同质量浓度下的沉降性能.结果表明,当质量浓度过低时,所有污泥都具有沉速快,泥水分界面模糊,沉后上清液浑浊的特性.当质量浓度升高时,沉速都会减慢,且泥水分界面分别因拥挤沉淀(不膨胀污泥)和交联分离(膨胀污泥)作用而变得清晰.当用污泥沉降比(SV)来表征沉降性时,不膨胀污泥对质量浓度变化敏感,而膨胀污泥则一直保持在90%以上.当用污泥容积指数(SVI)来表征沉降性时,对不膨胀污泥取沉降60 min的SVI可消除质量浓度的影响.对膨胀污泥需要设定一个特定质量浓度下的标准值,其他质量浓度下的SVI按照反比例关系换算到该质量浓度下再进行比较.

Impacts of mixed liquor suspended solids on settle ability in different activated sludge

In order to investigate the impacts of mixed liquor suspended solids(MLSS) concentration on sludge settleability,batch settling tests were carried out by 100 mL cylinders.The sludge settleability under different MLSS in non-bulking sludge,filamentous bulking sludge and non-filamentous bulking sludge dere investigated.The results show that,when MLSS was thin,all kinds of sludge had the characteristics of quick settling rate,fuzzy solid/liquid interface and tubid supernatant.When MLSS was dense,the settling speed would decrease.Meanwhile,the solid/liquid interface was changing clearer by the hindered settling(non-bulking sludge) and crosslinked separation(bulking sludge),respectively.When SV was used to describe sludge settleability,it was very sensitive to MLSS in non-bulking sludge,while it kept above 90% all the time in bulking sludge.When SVI was used to describe sludge settleability,the impacts of MLSS can be eliminated by calculating after settling 60 mins in non-bulking sludge.In bulking sludge,a standard SVI value under a certain MLSS should be set,the SVI under other MLSS could be conversed to the value under this MLSS according to inversely proportional relationship to compare sludge settleability.