活性污泥对低浓度市政污水中COD吸附性能的研究

Study on Adsorption of COD in Low Strength Municipal Wastewater by Activated Sludge

通过AB(Adsorption/Bio-oxidation)法的A段可以吸附去除污水中碳源,实现对碳源的回收利用。本文研究了吸附方式、污泥浓度、pH对活性污泥吸附性能的影响及活性污泥处理低浓度市政污水吸附等温线。结果表明,活性污泥进行厌氧吸附在10 min左右达到吸附平衡,进行好氧吸附在20 min左右达到吸附平衡,好氧吸附的吸附量高于厌氧吸附;吸附率均达到50%以上。在好氧吸附条件下,污泥浓度不会影响到达吸附平衡点的时间;污泥浓度越低,吸附量越高,吸附率越低,解吸过程越迅速;活性污泥吸附量几乎不受pH值的影响;pH越高,活性污泥的解吸过程越迅速。活性污泥对市政污水中化学需氧量(COD)的吸附等温线既符合Freundlich型,也符合Langmuir型。Freundlich型吸附等温线的吸附常数n在1~10之间,表明活性污泥是良好的吸附剂。

The Adsorption/Bio-oxidation (A/B) process can be used to recycle carbon source by adsorbing the carbon source in wastewater. In this paper, the influence of adsorption mode, sludge concentration and pH on Adsorption Properties of activated sludge was studied. Besides, the adsorption isotherm of treating low strength municipal wastewater by activated sludge was investigated. The results showed that the anaerobic adsorption of activated sludge reached adsorption equilibrium point after about 10 min, and the aerobic adsorption reached after about 20 min. The adsorption capacity of aerobic sludge was higher than that of anaerobic adsorption, and the adsorption efficiencies of them were above 50%. In aerobic adsorption conditions, sludge concentration didn’t affect the time of reaching the equilibrium point;the lower the sludge concentration was, the higher the adsorption capacity was, the lower the adsorption efficiency was, and the more quickly the desorption process was;pH can hardly affect the activated sludge adsorption capacity of activated sludge;the higher the pH was, the more quickly the desorption process was. The adsorption isotherm of activated sludge absorbing the chemical oxygen demand (COD) in low strength mu-nicipal wastewater fit well both the Freundlich equation and the Langmuir equation. The adsorp-tion constant n of the Freundlich equation was between 1~10, which indicated that activated sludge was a good adsorbent.