无机调理药剂复配对市政污泥脱水性能的影响

Effect of Mixed Inorganic Conditioning Agents on Municipal Sludge Dewaterability

以深圳市某污水处理厂浓缩污泥为对象,通过小试探究Na2SiO3与铁盐(铝盐)复配调理对污泥脱水性能的影响,初步确定污泥调理方案;然后利用高压隔膜压滤机开展中试验证。结果表明,Na2SiO3与铁盐(铝盐)复配调理的污泥脱水效果比单一药剂调理有明显改善。质量分数0.5%的Na2SiO3和质量分数4%的FeCl3复配调理后污泥脱水性能最好,污泥比阻(SRF)和毛细吸水时间(CST)分别降至134.5×109m/kg、11.6 s。原污泥经药剂调理后pH和黏度降低,沉降性改善。中试正交实验得到复配调理优化条件为:污泥的质量浓度35 g/L,复配药剂投加间隔时间15min,复配调理时间20 min,泥饼中水的质量分数降至47.12%。

The concentrated sludge from a sewage treatment plant in Shenzhen as the object,the sludge conditioning scheme was initially determined through a small-scale test which explored the effect of the mixed conditioning of sodium silicate and iron(or aluminum salts)on the dewatering performance of sludge.Then,a pilot test through using a high-pressure diaphragm filter press has been conducted to verify the scheme.The results showed that the dewatering effect of Na2SiO3 mixed with ferric or aluminum salt was better than that of single agent.The best sludge dewatering performance showed under the condition of Na2SiO3 with mass fraction of 0.5%and FeCl3 with mass fraction of 4%,which led to the decrease of specific resistance to filtration(SRF)to 134.5×109 m/kg and capillary suction time(CST)to 11.6 s.After conditioning the raw mud,the pH and viscosity reduced,and the precipitability improved.The optimum conditions of conditioner obtained through orthogonal experiment,the water mass fraction of sludge cake could decrease to 47.12%under the condition with sludge mass concentration was 35 g/L,dosing interval time of compound agents was 15 min and the mixed conditioning time was 20 min.