城市污泥生物沥浸法和化学法调理的效果比较——对污泥理化性质及其深度脱水性能的影响研究

分别用生物沥浸法（BC）、Fenton法和石灰/三氯化铁/PAM法（石灰法）对同一批城市污泥进行调理，并以常规PAM法（CC）为对照，探究不同调理后污泥的理化性质及其脱水性能的变化差异，并用流式细胞仪测定污泥中细胞裂解情况，以分析其机理.结果表明，BC法、Fenton法和石灰法均能大幅提高城市污泥脱水性能，表现在污泥过滤比阻（SRF）值仅为常规处理的0.43%~6.12%，尤其以石灰法处理脱水性能最佳.但BC法脱水泥饼中的有机质和养分能得到最大程度的保留，有机质（56.9%）、总氮（4.66%）、速效氮（0.47%）、矿化氮（1.80%）和总磷（1.60%）含量均远高于石灰法处理，而且污泥中重金属能被部分去除（Cr、Mn、Ni、Zn溶出率分别为18.7%、50.0%、48.7%和72.9%），该处理的污泥最具资源化潜力.而石灰法脱水泥饼由于大量脱水剂添加导致有机质（49.5%）、总氮（3.55%）和总磷（1.20%）含量明显下降，且泥饼呈强碱性（pH值接近11）.脱水滤液中的sCOD（645mg/L）和TP（4.62mg/L）也显著高于其他处理.流式细胞仪测定结果显示，BC法、Fenton法和石灰法均能导致污泥微生物凋亡，活细胞数量由原始的86%降至75%左右，特别是石灰法对污泥中细胞的破解效果最为彻底，从而释放出更多内部水和胞内物质，这可能是引起其有机质和养分大量损失至脱水滤液中的原因之一.与Fenton法和石灰法调理相比，生物沥浸法既具有能大幅提高污泥脱水性能，脱水滤液水质相对较好的优点，又具有泥饼有机质和氮磷养分高，重金属含量低的优点.

Effects of bioleaching and chemical conditioning on sludge dewaterability and physicochemical properties

Three widely used conditioning methods, including bioleaching (BC), Fenton oxidation (FC), and chemical addition of lime/FeCl₃/PAM (LC), were investigated to determine their effects on sludge dewaterability and physicochemical properties. The results showed that the BC, FC, and LC conditioning methods significantly improved sludge dewatering performance, as exhibiting that specific resistance to filtration (SRF) of already-conditioned sludge by BC, FC and LC only were 0.43%~6.12% of that by conventional PAM addition treatment (CC). Furthermore, compared to chemical treatments (FC and LC), relatively high quantities of plant nutrients (56.9% of organic matter, 4.66% of total nitrogen, 0.47% of water soluble nitrogen, 1.80% of mineralized nitrogen, and 1.60% of total phosphorus) were retained in the dewatered sludge of bioleaching treatment. Meanwhile, after bioleaching treatment, 18.7% of Cr, 50.0% of Mn, 48.7% of Ni and 72.9% of Zn were removed from sludge, respectively. Flow cytometry was further used to examine the variation of sludge cell apoptosis before and after the three conditioning methods. It was found that dosing chemical conditioners (FC and LC) lead to the obvious lysis of the sludge cells and accordingly a large amount of internal water and intracellular substances within the sludge flocs were released, which may be responsible for their increased plant nutrients release and improved sludge dewaterability. The results suggested that bioleaching treatment exhibited excellent performance in improving sludge dewatering and heavy metal removal and maintaining sludge nutrients, therefore it's promising conditioning approach for sludge disposal.