化学调质污泥深度脱水过程及其潜在影响研究

分别依次投加定量的氯化铁(FeCl_3)、生石灰(CaO)和阳离子聚丙烯酰胺对污水处理厂浓缩池污泥进行调理,通过测试污泥的沉降速率、比阻、粒径、Zeta电位、胞外聚合物和脱水液水质等指标,考察不同脱水药剂对污泥形态和脱水性能的影响。结果表明:FeCl3的混凝作用使污泥颗粒更小更密实;投加CaO能够在污泥内部形成新的矿物相和刚性结构,构建污泥脱水骨架,同时形成的碱性条件使铁离子形成胶体羟基聚合物而强化混凝效果;阳离子聚丙烯酰胺则可以明显增加污泥絮体粒径。污泥紧密结合型胞外聚合物脱落后释放部分束缚水,增强了污泥脱水性能,使污泥脱水效率明显提高。但是采用CaO作为污泥脱水药剂引起的破壁作用可导致脱水滤液水质恶化,大量难降解有机物等污染物回流至污水处理厂会对其正常运行造成不利影响。     

阳离子表面活性剂改善污泥脱水性能的机理研究

研究了两种含有不同长度疏水链的阳离子表面活性剂CSG—1和CSG-2对活性污泥脱水性能的影响，探讨了两种活性剂在活性污泥体系中的作用机理。结果表明，投加约为干污泥质量10％的CSG-1可使滤饼的含水率降至78％左右，此时污泥的沉降效果较好，污泥毛细吸水时间（CST）也较短（约为62s）；与CSG-1相比，CSG-2虽可使滤饼含水率降至约74％，但其对污泥过滤性能和沉降效果的改善均较差。对CSG—1和CSG-2改善污泥脱水性能的机理研究表明，阳离子表面活性剂通过静电引力和范德华力而被吸附于污泥表面，改变了活性污泥絮体的特性，并引起胞外聚合物（EPS）的分布发生变化，从而改善了污泥的脱水性能，同时也导致了絮体颗粒粒径发生了显著变化。     

不同调理剂对含油污泥脱水性能的影响研究

含油污泥直接脱水处理,效率低且成本高,需进行调理以改善脱水性能。采用芬顿试剂、表面活性剂和改性生物质对含油污泥进行调理,对比调理前后的污泥脱水性能参数,分析其污泥调理机理。结果表明,三种调理剂对含油污泥脱水性能的影响大小为:改性生物质芬顿试剂表面活性剂;当改性生物质的投加量为50 mg/g DS时,调理后滤饼含水率降至55%,比阻为1.1×10~8s~2/g,上清液中多糖、蛋白质和SCOD含量分别为95、210和600 mg/L。SEM照片和FTIR谱图表明,改性后的生物质不仅具有吸附作用,而且表面含有丰富的含氧基团,可以交换污泥絮体中的离子,使污泥内部化学平衡遭到破坏,从而改善污泥的脱水性能。     

厌氧消化污泥脱水性能变化的试验与分析

研究了剩余污泥在中温厌氧消化条件下脱水性能的变化及其作用机制。剩余污泥厌氧消化过程中,消化污泥的比阻(SRF)相比于剩余污泥有一定的减小,消化污泥的过滤速度有一定的改善,但改善不明显。聚丙烯酰胺(PAM)、FeCl3和聚合氯化铝(PAC)3种絮凝剂调理试验显示,消化污泥的最佳投药量相对于剩余污泥均有所增加,说明消化污泥脱水性能变差。分析了2种污泥中胞外聚合物(EPS)含量及污泥颗粒特性的变化,表明消化过程导致EPS的降解并向液体中释放。随着EPS含量的减少,由EPS架桥形成的较大絮体解体成为较小的污泥颗粒,污泥中小颗粒的比例增加,污泥的脱水性能变差。     

聚丙烯酰胺对水厂污泥脱水性能影响的研究

通过观察不同絮凝剂形成絮体的情况、絮体沉淀效果、对沉降速度的测定,研究了阴阳离子不同相对分子质量聚丙烯酰胺（PAM）对水厂污泥脱水性能的影响。结果表明,阴、阳聚丙烯酰胺因其具有吸附架桥的作用,能够改变污泥絮体结构,能够提高污泥的脱水和沉降性能,其脱水和沉降性能与阴阳离子和相对分子量有密切的关系。     

表面活性剂对污泥沉降及脱水性能的影响

研究了表面活性剂对污泥沉降及脱水性能的影响,结果表明,表面活性剂的加入不但加快了污泥的沉降速度,而且降低了脱水污泥的含水率。当加入量为0.12g/100mL时,污泥的初始沉降速度最快;当加入量为0.4g/100mL时,脱水污泥的含水率比不加表面活性剂时降低了约5％。进一步的研究显示,表面活性剂能使污泥颗粒表面的蛋白质和DNA释放出来。     

污水厂改性污泥脱水性能研究

本研究选取两种常用的无机调理剂聚合氯化铝(PAC)和聚合硫酸铁(PFS)对污水厂污泥脱水性能进行改善实验研究。结果显示,污泥脱水性能改善最明显时,PAC和PFS的投加量都为2.0 g/L。而且,污泥的比阻值和污泥的含水率之间有着密切的相关性。从经济成本角度考虑,使用PFS进行污泥调理更为经济合适。     

蚯蚓生物滤池处理剩余污泥的脱水性能研究

蚯蚓生物滤池基于蚯蚓与微生物的协同作用,可有效实现剩余污泥的减量化和稳定化,其中由于蚯蚓的摄食、咀嚼和消化等作用及蚓粪的团聚作用可有效改善污泥的脱水性能。在有机负荷为2.43 kg VSS/(m~3·d)的条件下,结合持泥量变化情况,比较了木珠、鲍尔环、瓷球三种不同填料的蚯蚓生物滤池处理剩余污泥的减量化和稳定化效果,并选取运行最稳定高效的木珠填料生物滤池进行脱水性能试验。以污泥比阻、毛细吸水时间、Zeta电位、污泥颗粒粒径、絮体结构、EPS为指标,考察了处理前后污泥脱水性能的变化。结果表明,经蚯蚓生物滤池处理后的污泥比阻和毛细吸水时间减少,Zeta电位升高,污泥颗粒粒径增大,絮体结构更为紧密,脱水性能大大改善。最后结合蚯蚓与微生物的相互作用关系,分析了蚯蚓生物滤池改善污泥脱水性能的机制。     

颗粒/絮体共存的生物除磷系统的特性研究

以颗粒/絮体共存的SBR生物除磷系统为研究对象,考察了生物除磷污泥的形成过程、颗粒/絮体共存及各自单独存在下的污泥特性和除污性能。在40 min的沉淀时间下,以厌氧/好氧交替方式运行的SBR反应器中有白色颗粒污泥出现,随着运行则系统处于颗粒和絮体共存的状态。运行至第60天,污泥的平均粒径为553μm,颗粒(粒径200μm)占污泥总量的比例为67%。颗粒/絮体共存的形式可以提高絮体污泥的沉降性能,同时降低颗粒污泥解体所导致的出水SS浓度的增加。另外,颗粒/絮体共存系统对COD、PO3-4-P、NH+4-N的去除率分别为80%、98.5%、100%。而单独颗粒系统的出水NH+4-N为7.63 mg/L,单独絮体系统的出水PO3-4-P为5.87 mg/L。颗粒与絮体共存更有利于对污染物的去除及污泥沉降性能的改善。     

稻壳粉调理对污泥脱水性能及脱水液水质的影响

采用稻壳粉作为骨架构建体替代无机调理剂(生石灰),通过测定污泥比阻、毛细吸水时间、Zeta电位及滤饼有机物含量和含水率、滤液水质指标,探讨稻壳粉及其协同聚丙烯酰胺和Fe Cl3对污泥脱水性能及脱水液水质的影响。结果表明,稻壳粉作为骨架构建体能够降低污泥的可压缩性,提高污泥的脱水性能,降低污泥泥饼含水率,并且投加量为30%时效果最好。当稻壳粉协同聚丙烯酰胺和Fe Cl3的投加量分别为0.07%和7%时,可以明显降低污泥毛细吸水时间、污泥比阻和污泥泥饼含水率。同时,稻壳粉调理污泥能显著改善脱水液水质、降低COD和氨氮值,从而减轻污水厂的运行负担。对比运行效果和经济成本发现,稻壳粉可以取代生石灰作为污泥调理剂。     

Effect of acid and surfactant treatment on activated sludge dewatering and settling.

The effect of pretreating activated sludge with sulfuric acid and surfactant on its exocellular polymer(ECP), dewaterability and settleability was investigated. It was observed that the centrifugal dewatering efficiency was increased with the decrease of sludge pH value, and which was further improved if the surfactant was simultaneously applied. However, to the filtration dewatering, the water content reached the minimum in the case of pH 2.5, and the additional use of surfactant was also favorable. The water content of sludge dewatered with filtration reached 73.99% when a pH 2.5 and a 0.1 g surfactant were employed, which was reduced by around 2% as compared with surfactant unused. Experimental results indicated that the sludge sedimentation rate was significantly accelerated under pH 2.5 condition, and which was increased once more by the utilization of surfactant. Further studies revealed that treating activated sludge with sulfuric acid at pH 2.5 or combined with surfactant was an effective method to remove the polymers from sludge surface and induced the decrease of ECP, which resulted in the improvement of dewaterability and settleability. This study suggested the potentiality of improving activated sludge mechanical dewaterability by the use of sulfuric acid to control its pH at 2.5 or together with a surfactant.     

Physical and chemical properties of activated sludge floc

Physical and chemical characteristics of activated sludge such as floc size, density, specific surface, carbohydrate content, dehydrogenase activity and settleability were investigated by seven parallel bench scale activated sludge units operated under different sludge ages (1.1–17.4 days). The analytical methods used included a dye adsorption technique for specific surface area determinations, the Coulter Counter method for floc size measurements and interference microscopy for floc density determinations. The typical floc sizes were found to be in the range 10–70 μm with floc densities in the range 1.015–1.034 g cm⁻³. A strong correlation between floc density and size was obtained. The specific surface areas measured (typically 100–200 m² g⁻¹ dry sludge) were found to be one to two orders of magnitude higher than the corresponding geometric floc surface areas, indicating a porous floc structure. Sludge settleability, for non-filamentous sludges, was well correlated to both floc size, density and specific surface area, but not to the sludge carbohydrate content, which was found to vary between 6 and 18%.     

复合混凝剂对MBR工艺中污泥性能的影响研究

为了缓解MBR工艺的膜污染,向MBR工艺中投加复合混凝剂,考察了复合混凝剂对污泥性能的影响.结果表明,投加复合混凝剂可降低污泥比阻,明显增大污泥絮体的平均粒径、降低其分形维数,且污泥的可溶性微生物产物(SMP)含量也明显下降,这样有利于增强污泥的沉降性能、降低膜滤饼层的污染、增强膜表面的透水性.     

Dewatering characteristics of sludge conditioned by surfactant with bioleaching pretreatment

In view of the merits of bioleaching and surfactant for sludge treatment, the possibility of surfactant with bioleaching pretreatment applied to improve sludge dewaterability was investigated in this work. The results showed that cetyl trimethyl ammonium chloride (CTAC) with bioleaching pretreatment was highly efficient in dewatering sludge. The optimal CTAC dosage and bioleaching pH for this combination were 120 mg/g (dry solids) and 3.55, respectively, under which the water content of filtrated cake was 68.94% and the specific resistance to filtration was 0.12 × 10¹³ m/kg with a reduction of 94.92%. Although CTAC and bioleaching both had positive effects on sludge dewatering, their combination was more efficient. The significant enhancement of sludge dewaterability was mainly contributed from the breakage and charge neutralization of sludge flocs, and the release of extracellular polymeric substances (EPS). In addition, the positive correlation between supernatant EPS concentration and sludge dewaterability was observed under experimental conditions.     

Enhanced settleability and dewaterability of fungal treated domestic wastewater sludge by liquid state bioconversion process

A study was conducted to evaluate the settleability and dewaterability of fungal treated and untreated sludge using liquid state bioconversion process. The fungal mixed culture of Aspergillus niger and Penicillium corylophilum was used for fungal pretreatment of wastewater sludge. The fungal strains immobilized/entrapped on sludge particles with the formation of pellets and enhanced the separation process. The results presented in this study showed that the sludge particles (pellets) size of 2-5mm of diameter were formed with the microbial treatment of sludge after 2 days of fermentation that contained maximum 33.7% of total particles with 3-3.5mm of diameter. The settling rate (measured as total suspended solids (TSS) concentration, 130 mg/l) was faster in treated sludge than untreated sludge (TSS concentration, 440 mg/l) after 1 min of settling time. In 1 min of settling operation, 86.45% of TSS was settled in treated sludge while 4.35% of TSS settled in raw sludge. Lower turbidity was observed in treated sludge as compared to untreated sludge. The results to specific resistance to filtration (SRF) revealed that the fungal inoculum had significant potentiality to reduce SRF by 99.8% and 98.7% for 1% w/w and 4% w/w of TSS sludge, respectively. The optimum fermentation period recorded was 3 days for 1% w/w sludge and 6 days for 4% w/w sludge, respectively, for dewaterability test.     

Microsphere addition for the study of biomass properties and density effects on settleability in biological wastewater treatment systems

Recent research has demonstrated that biomass density can vary in activated sludge systems, and that this can affect biomass settleability. Other factors related to floc structure are well known to affect settleability, and these can also vary considerably across samples. A new method to isolate density effects on sedimentation was developed and applied based on the addition of commercially available, high and low density microspheres. Density was a linear function of microsphere dose in five full-scale samples, and it was negatively correlated with sludge volume index (SVI) values. Density effects on SVI were similar to previous reports where density varied with biomass polyphosphate content. A new method to calculate water content and floc volume was developed and applied, and water content was inversely correlated with density, polyphosphate, and non-volatile suspended solids. These results suggest microsphere addition may be useful in future studies of biomass sedimentation and other properties.     

基于絮体结构指标的丝状菌膨胀污泥SVI预测

为了建立更加准确的膨胀活性污泥沉降性表征方法,筛选出5个反映污泥微观絮体结构的特征指标:絮体大小(SZ)、伸长性(ST)、密实性(CP)、规则性(RG)和丝状菌(FL),分析众多特征参数降维的可能性,建立丝状菌膨胀污泥絮体结构特征指标体系,以偏最小二乘回归法(PLS)探索膨胀污泥絮体结构特征指标与污泥容积指数(SVI)的关系,建立丝状菌膨胀污泥的SVI预测函数。结果表明,污泥絮体特征参数之间具有较好的相关性,可采用主成分分析法(PCA)进行降维。污泥絮体结构特征指标与丝状菌膨胀活性污泥的SVI之间有较强的线性相关性(R2=0.779),据此建立了SVI预测模型,丝状菌膨胀污泥的SVI实测值与预测值呈现较强的线性相关性(R2=0.801),模型能较好地预测丝状菌污泥膨胀。     

Evolution of size distribution and transfer of mineral particles between flocs in activated sludges: an insight into floc exchange dynamics

The aggregation behavior of activated sludge flocs was investigated by monitoring the size distribution of flocs and transfer of mineral particles between flocs, under various conditions of agitation and dilution. The results showed that (i) the shape of the floc size distribution can be fitted with a gamma function, (ii) a steady-state mean floc size is reached for a given stirring rate, (iii) this stable floc size is shifted towards floc growth as sludge concentration is increased, (iv) under cycled-shear conditions, microbial aggregates break up and re-form in an almost reversible manner, (v) blending of raw sludge and sludge spiked with Aquatal mineral particles results in particle exchange between flocs and (vi) the detailed study of exchange kinetics indicates that some flocs do not participate to the aggregation dynamics. These experimental results suggest that the activated sludge floc size is governed by a flocculation/deflocculation balance, implying an exchange of floc constituents between microbial aggregates.     

Filtration properties of activated sludge in municipal MBR wastewater treatment plants are related to microbial community structure

In the conventional activated sludge process, a number of important parameters determining the efficiency of settling and dewatering are often linked to specific groups of bacteria in the sludge – namely floc size, residual turbidity, shear sensitivity and composition of extracellular polymeric substances (EPS). In membrane bioreactors (MBRs) the nature of solids separation at the membrane has much in common with sludge dewaterability but less is known about the effect of specific microbial groups on the sludge characteristics that affect this process.     

城市污水处理厂污泥的好氧处理研究

为了实现污泥的稳定化、减量化和无害化,对城市污水处理厂的浓缩污泥和厌氧消化污泥进行了好氧处理试验研究.试验结果表明,污泥好氧处理使污泥中有机物质含量降低,臭味减小.厌氧污泥经好氧消化处理后,一方面使污泥得到稳定化和减量化;另一方面,可以把污泥中的致病菌杀死.污泥经好氧消化后沉降性能有明显提高,絮凝剂的加入使其脱水性能也得到一定的改善.