热碱解-水解预处理剩余污泥的效果研究

The Effect of Pretreatment of Residual Sludge with Thermal-Alkaline Combined with Hydrolysis Process

热碱解-水解联合工艺预处理剩余污泥,可以实现污泥快速破胞,释放污泥细胞中的有机物,促进水解过程物质的转化,也有利于回收剩余污泥中的碳源.基于此优点,本研究考察了温度、p H、反应时间对剩余污泥热碱解破胞效果的影响,以确定适宜的热碱解条件.比较了不同水力停留时间(HRT=0～120 h)下污泥水解过程中SCOD、挥发性脂肪酸(VFAs)、氮、磷、蛋白质和糖类的质量浓度的变化,分析了水解过程中物质的转化情况.结果表明:较高的p H(p H>11.0)、较高的温度和延长反应时间均有利于提高污泥破胞效果.适宜的热碱解条件为:热碱解破胞温度为70℃、初始p H=11.0,反应时间1.0 h.在该条件下,SCOD的质量浓度可超过10 500 mg/L,污泥溶胞率为44.0%.在水力停留时间为24 h时,VFAs和SCOD的质量浓度分别高于2 400 mg/L和5 800 mg/L.研究发现热碱解-水解反应约120 h达到平衡,此时蛋白质和糖类的质量浓度稳定在130 mg/L和190 mg/L左右,其中,氮、磷主要以NH4+-N和PO34-形式存在.热碱解-水解联合工艺通过加速污泥破胞,释放胞内有机物,能显著促进污泥的水解,为剩余污泥热碱解-水解预处理的应用提供了技术支撑和理论依据.

Thermal-alkaline combined with hydrolysis process( TAHP) pretreating residual sludge can rapidly achieve sludge disintegration,release organic matter from residual sludge,promote the conversion of substances in the hydrolysis process,and facilitate the recovery of carbon source from residual sludge. In this study,temperature,pH and reaction time,as the influence factors in sludge disintegration,were investigated to determine the appropriate thermal-alkaline pretreatment conditions. The concentrations of SCOD,volatile fatty acids( VFAs),nitrogen and phosphorus,protein and carbohydrates during TAHP under different hydraulic retention time( HRT = 0 ~120 h) were compared,and the conversion of substances in the hydrolysis process was analyzed. The experimental results showed that the higher pH( pH>11.0),higher temperature and longer reaction time were beneficial to increasing the effect of sludge disruption. The appropriate conditions of thermal-alkaline pretreatment were as follows:temperature of sludge disintegration was 70 ℃,initial pH was 11.0,and reaction time was 1.0 h respectively. Under this condition,the concentration of SCOD could exceed 10 500 mg/L and the sludge lysis ratio was 44. 0%.When HRT was 24 h in hydrolysis process,the concentration of VFAs and SCOD could exceed 2 400 mg/L and5 800 mg/L respectively. TAHP reached equilibrium at about 120 h,protein and carbohydrates were stable at 130 mg/L and 190 mg/L respectively. And nitrogen and phosphorus were mainly present in the form of NH4+-N and PO34-. TAHP could accelerate the hydrolysis of sludge by accelerating the sludge disintegration and releasing intracellular organics,which will provide technical support and theoretical basis for the application of TAHP.