污泥碱解和超声破解预处理的效果研究

为提高污水厂污泥的厌氧消化速率,采用多频率多功率槽式超声发生器,研究了超声波、碱解、以及两者的组合作用对污泥破解预处理效果的影响.结果表明,碱和超声波的组合预处理方式,对污泥溶解性COD的释放效果和VSS减少效果明显优于单独的超声波和单独的碱处理.单独超声预处理,污泥VSS的最大减少率为15.98%;单独碱解(NaOH/TS=0.04)时为22.12%;先碱解(NaOH/TS:0.04,24 h),再超声(60 min)以及碱(NaOH/TS=0.04)和超声(60 min)同时作用的预处理方式,可将污泥VSS减少率分别提高到51.45%和54.45%.破解作用引起污泥的水解分为快速水解和缓慢水解2个阶段,对快速水解阶段进行动力学分析可知,同时采用碱和超声的预处理方式不但可以获得最高的水解速率,而且降低了碱的投加量,缩短了超声破解的时间.     

碱处理玉米秸秆与超声预处理污泥混合厌氧消化效果研究

以碱处理玉米秸秆和超声预处理污泥为发酵原料,在恒温35±1℃及底物浓度为15 gVS/L的条件下,采用正常运行的大型沼气池沼液作为接种物,研究不同配比(VS污泥:VS秸秆分别为1:0、2:1、1:1、1:2、1:4)对混合厌氧消化效果的影响.研究表明,VS污泥:VS秸秆的比例为1:2时累积产气量最高,VS产气率达到了472.33 mL·g-1,甲烷产量在发酵稳定后达到了60.52%.进一步研究得出,将超声预处理污泥与碱处理玉米秸秆按一定比例混合发酵可以将产气高峰提前.     

污泥预处理对微生物絮凝剂制备及性能的影响

试验研究了不同污泥预处理方法对微生物絮凝剂的制备及其絮凝性能的影响.结果表明,污泥经碱热预处理后释放的有机物质量最大,SCOD/TCOD可达到0.56.以碱热预处理污泥作为基质制备的微生物絮凝剂,其产量为2.3 g·L-1,高于热预处理的1.6 g·L-1,酸热预处理的0.6 g·L-1,以及未接种污泥絮凝剂的18 mg·L-1.采用响应面分析法对碱热预处理污泥制备的微生物絮凝剂与PAM复配改善污泥脱水的过程进行了优化,实验分别拟合了关于污泥比阻(SRF)和干污泥量(DS)的二次模型,决定系数(R2)分别为0.9057和0.9171,表明拟合情况良好.实验中最佳的污泥脱水条件为微生物絮凝剂投加量12.6 g·kg-1,PAM投加量1.0 g·kg-1,Ca Cl2投加量59.7 mg·L-1,p H值6.7,搅拌速度185r·min-1.在此条件下,DS和SRF分别为29.1%和2.2×1012m·kg-1,表明碱热预处理污泥制备的微生物絮凝剂与PAM的联合使用有助于改善污泥脱水性能.     

酸-碱预处理促进剩余污泥厌氧消化的研究

为提高剩余污泥的厌氧消化效率,投加酸和碱对污泥进行预处理,对比分析了不同预处理方式（单独碱处理、酸-碱处理和碱-酸处理）对污泥水解酸化的影响,并研究了各种预处理方式对后续厌氧消化产甲烷效率的影响.结果表明,单独碱处理的溶解性化学需氧量（SCOD）溶出量比酸碱联合处理要大16%左右,预处理第8 d,达到5 406.1 mg.L-1.采用先酸（pH 4.0,4d）后碱（pH 10.0,4 d）预处理,在污泥水解酸化过程中,乙酸产量及其占总短链脂肪酸（SCFAs）的质量分数均高于其他预处理方式,其乙酸产量（以COD/VSS计）可达到74.4 mg.g-1,占总SCFAs的60.5%.酸-碱预处理后污泥混合液的C∶N比值为25左右,C∶P比值在35～40之间,这比单独碱处理和碱-酸处理后的C∶N和C∶P比值更有利于后续厌氧消化.通过对比研究发现,酸-碱预处理后,厌氧消化到第15 d,酸-碱预处理污泥的累积甲烷产量（CH4/VSS加入）达到136.1 mL.g-1,分别是空白对照、碱-酸预处理和单独碱预处理方式的2.5、1.7和1.6倍,厌氧消化效率最高.经过8 d酸-碱预处理和15 d的厌氧消化,挥发性悬浮固体（VSS）总去除率达到60.9%,污泥减量效果比其他预处理要好.很显然,酸-碱预处理方式更有利于污泥厌氧消化及污泥减量化.     

CaO对高浓度污泥厌氧消化性能的影响机理及动力学分析

为解决高固体浓度污泥厌氧消化水解速率慢的问题,采用CaO对高固体浓度污泥进行碱解预处理.采用粒径分析及溶解性COD、蛋白质和多糖浓度监测考察碱解预处理前后污泥物理化学特性的变化,评估碱解预处理对高固体浓度污泥厌氧消化产甲烷潜力及有机物降解规律的影响,研究不同碱量下EPS、细胞壁和细胞膜破解程度对厌氧消化性能的影响机理,...     

中温碱解预处理促进剩余污泥厌氧产甲烷的研究

采用4 mol/L NaO H碱液在中温下处理城市生活污水处理厂剩余污泥6 h,对比原剩余污泥和中温碱解污泥厌氧消化产甲烷的能力,分析了中温碱解及厌氧消化过程中剩余污泥胞内物质的释放规律,结果表明:碱解预处理有效促进了有机物、氨氮的释放,对磷酸盐释放促进作用不明显。原剩余污泥的沼气转化效率为387.5 L/kg(以VS计,下同),中温碱解处理组的沼气转化效率为402.5 L/kg;中温碱解处理组沼气转化效率比原剩余污泥组高3.87%;中温碱解预处理提高了污泥减量化程度及甲烷产量。改进的Gompertz模型结果表明:碱解处理后剩余污泥最大甲烷产量为1 480.7 mL,最大产甲烷速率为77.8 mL/d,细菌产甲烷的延迟时间为3.38 d。     

不同污泥预处理方法对污泥厌氧消化产气量影响研究

污泥溶胞破解是提高污泥厌氧消化产气量的重要手段。实验比较了热预处理、碱预处理、热碱预处理以及电化学热处理四种破解方法对污泥厌氧消化产气量的优化效果,通过对沼气累计产量、日产气速率、CH4在沼气中的含量占比等指标的分析,结果表明,不同的破解方法对污泥厌氧消化产气量的优化程度是不同的。     

碱热联合破解污泥效果及动力学研究

研究了碱热联合处理对污泥的破解效果并进行了动力学分析.结果表明,碱的加入显著提高了热处理的破解效果,NaOH的破解效果比Ca(OH)2好.碱热联合处理脱水泥饼的适宜处理参数为140℃、90min、Ca(OH)2和NaOH投加量为0.25g/g总固体(TS).在该条件下,溶解性化学需氧量(SCOD)比未加碱时分别增加了41.26%和198%,质量减少率分别为50%、57%.采用NaOH碱热破解污泥后的SCOD值与热处理温度(T)、处理时间(t)及投碱量(A)的关系可以用幂指数模型表示:SCODNa=10178.17[T ]0.43 [A ]0.59t 0.24.     

碱预处理提高污泥产甲烷潜力(BMP)研究

以济南某生活污水处理厂的污泥为研究对象,考察碱预处理对污泥粒径和产甲烷潜力（BMP）的影响。调节污泥混和液的pH值至11左右后与未作处理的原污泥进行对比分析,结果表明,碱预处理对污泥有很好的分散作用,可以将较大粒径的污泥絮体分散为较小粒径的污泥絮体;未处理的污泥10d左右产甲烷量达到最高约为165ml／gVSS,而碱预处理后的污泥在6d左右产甲烷量就高这245ml／gVSS,碱预处理后污泥的产甲烷量不但明显增加,而且产甲烷所需时间也大大缩短。     

Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency. Uniform design was applied to determine the combination of target temperature (110–210°C), microwave holding time (1–51 min), and NaOH dose (0–2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization. Maximum solubilization ratio (85.1%) of VSS was observed at 210°C with 0.2 g-NaOH/g-SS and 35 min holding time. The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP). Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge. The highest CMP was a 27% improvement over the control. In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge, a semi-continuous thermophilic reactor fed with pretreated TWAS without neutralization (at 170°C with 1 min holding time and 0.05 g NaOH/g SS) was stable and functioned well, with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%, respectively, which were higher than those of the control system. Additionally, methane yields (L@STP/g-CODadded, at standard temperature and pressure (STP) conditions of 0°C and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%, respectively, compared to the control reactor.     

预处理破稳污泥木质纤维素并厌氧降解实验研究

剩余污泥中往往含有大量木质纤维素物质,其在厌氧消化过程中难以降解,最终残留于熟污泥中,这也是导致污泥有机物稳定并转化能源效率低下的主要原因之一.针对污泥中木质纤维素的结构稳定性,本实验选择酸、碱、热解及超声波4种预处理方式,采用适宜的条件预处理剩余污泥,在一定程度上破坏污泥中木质纤维素结构,继而进行污泥厌氧消化,获得了较好的木质纤维素降解率.同时,实验筛选出热解为最佳的预处理技术方式.在T=150℃与t=30 min预处理工况下,污泥在厌氧消化后最高可实现52.6%的木质纤维素降解率,主要归功于半纤维素和纤维素的大幅降解.相对未预处理污泥,预处理能有效促进木质纤维素类物质的厌氧消化,从而提高污泥有机质的能源转化率.     

Enhanced anaerobic digestion and sludge dewaterability by alkaline pretreatment and its mechanism

To investigate the influences of alkaline pretreatment on anaerobic digestion (AD) and sludge dewaterability after AD, waste activated sludge was adjusted to different pH values (8, 9, 10, 11, 12) and placed at ambient temperature for 24 hr. The samples were then adjusted to the initial pH and subjected to 25 days of AD. The results showed that, when compared with the control (pH 6.8), total suspended solids (TSS) and volatile suspended solids (VSS) reduction following pretreatment at pH 9-11 increased by 10.7%-13.1% and 6.5%-12.8%, respectively, while biogas production improved by 7.2%-15.4%. Additionally, significant enhancement of sludge dewaterability after AD occurred when pretreatment at pH 8-9 was conducted. The proteins and carbohydrates transferred from the pellet and tightly bound extracellular polymeric substances (TB-EPS) fractions to the slime and loosely bound EPS (LB-EPS) fractions after pretreatment and during the AD process, and the concentrations of proteins and carbohydrates in the slime fraction had a good linear relationship with the normalized capillary suction time (CST). During the AD process, the normalized CST was positively correlated with the organic materials in the loosely bound fraction of the sludge matrix (R^{2≥qslant 0.700, p < 0.01), while it was negatively correlated with the organic materials in the tightly bound fraction (R2≥qslant 0.702, p < 0.01). These results suggest that alkaline pretreatment could break the EPS matrix and release inner organic materials, thus influencing the efficiency of the AD process and dewaterability after AD.}     

Combined alkaline and ultrasonic pretreatment of sludge beforeaerobic digestion

Alkaline and ultrasonic sludge disintegration can both be used as pretreatments of waste activated sludge (WAS) for improving the subsequent anaerobic or aerobic digestion. The pretreatment has been carried out using different combination of these two methods in this study. The effect was evaluated based on the quantity of soluble chemical oxygen demand (SCOD) in the pretreated sludge as well as the degradation of organic matter in the following aerobic digestion. For WAS samples with combined pretreatment, the released COD was in high level than those with ultrasonic or alkaline treatment. When combined with the same ultrasonic treatment, NaOH treatment resulted in more solubilization of WAS than Ca(OH)2. For combined NaOH and ultrasonic treatments with different sequences, the released COD were in the order: simultaneous treatment > ultrasonic treatment following NaOH treatment > NaOH treatment following ultrasonic treatment. For simultaneous treatment, low NaOH dosage (100 g/kg dry solid), short duration (30 min) of NaOH treatment, and low ultrasonic specific energy (7 500 kJ/kg dry solid) were beneficial for sludge disintegration. Using combined NaOH and ultrasonic pretreatment with the optimium parameters, the degradation efficiency of organic matter was increased from 38.0% to 50.7%, which is much higher than with ultrasonic (42.5%) or with NaOH pretreatment (43.5%) in the subsequent aerobic digestion at the same retention time.     

Effect of ultrasonic pretreatment on anaerobic digestion and its sludge dewaterability

To investigate the effect of ultrasonic pretreatment on anaerobic digestion and sludge dewaterability and further to probe into the influencing factors on sludge dewaterability, sludge flocs were stratified into four fractions: (1) slime; (2) loosely bound extracellular polymeric substances (LB-EPS); (3) tightly bound EPS (TB-EPS); and (4) EPS-free pellets. The results showed that ultrasonic pretreatment increased the anaerobic digestion efficiency by 7%–8%. Anaerobic digestion without ultrasonic pretreatment deteriorated the sludge dewaterability, with the capillary suction time (CST) increased from 1.42 to 47.3 (sec L)/g-TSS. The application of ultrasonic pretreatment firstly deteriorated the sludge dewaterability (normalized CST increased to 44.4 (sec L)/g-TSS), while subsequent anaerobic digestion offset this effect and ultimately decreased the normalized CST to 23.2 (sec L)/g-TSS. The dewaterability of unsonicated sludge correlated with protein (p = 0.003) and polysaccharide (p = 0.004) concentrations in the slime fraction, while that of sonicated sludge correlated with protein concentrations in the slime and LB-EPS fractions (p < 0.05). Fluorescent excitationemission matrix analysis showed that the fluorescence matters in the LB-EPS fraction significantly correlated with sludge dewaterability during anarobic digestion.     

预处理对造纸污泥厌氧消化产甲烷性能的影响研究

采用碱(NaOH)和生物(蘑菇渣、绿色木霉)2种方法分别预处理造纸污泥,并将预处理后的造纸污泥与味精废液进行联合厌氧消化,研究不同预处理方式对造纸污泥的影响以及对后续联合厌氧消化甲烷产率的影响.结果表明,造纸污泥经过碱(NaOH)预处理和生物预处理(蘑菇渣、绿色木霉)后,污泥颗粒的结构变得紧实、平滑,颗粒间的孔隙度减少,污泥絮体中的纤维长度明显变短、污泥中的SCOD增加了35.5%~1130%、VSS降低了6%~19%、SVsludge增加了32%~192%,NH3-N浓度提高了36%~62.4%,表明预处理后污泥中的大分子物质被降解成小分子物质,且碱预处理对污泥产生的变化较生物处理大;经预处理后的造纸污泥与味精废液联合厌氧消化,甲烷得率分别为:NaOH预处理0.32m3 CH4/kg VS、蘑菇渣预处理0.23 m3 CH4/kg VS,较CK分别提高了54%~88%和12%~34%,可见碱预处理提高甲烷产率效果更明显,由于蘑菇渣预处理具有成本低、解决二次污染、实现废物再利用等优点,因此两者在预处理提高造纸污泥厌氧消化甲烷产率方面都具有重要意义.     

剩余污泥预处理技术概览

全球气候大会以及中国政府在CO2减排方面的承诺使剩余污泥厌氧消化产生能源这一老生常谈的问题再次受到关注.污泥生物细胞裂解/水解是限制厌氧消化效率的重要瓶颈,而污泥预处理技术可有效提高细胞破裂、水解效果,最大限度地发掘出剩余污泥中的有机能源.目前全球研发的污泥预处理技术多种多样,其中既有具备工程应用经验的超声波、聚焦脉冲...     

城市污泥厌氧消化和脱水工艺对肠道病原菌的杀灭效应

运用最大或然数(MPN)培养法和定量PCR(qPCR)技术对不同城市污水处理厂污泥厌氧消化处理和脱水处理前后,污泥中埃希氏大肠杆菌(E.coli)、沙门氏菌(Salmonellaspp.)和志贺氏菌(Shigellaspp.)含量的变化进行了研究.MPN检测结果表明,污泥中大肠杆菌、沙门氏菌和志贺氏菌数量经厌氧消化处理后明显下降,平均下降2～5个数量级,但qPCR检测结果显示,种病原菌平均下降1～2个数量级.脱水处理3后,污泥中的肠道病原菌含量基本没有变化,没有发生脱水后再生长现象.大肠杆菌、沙门氏菌和志贺氏菌含量分别在104～107、104～105和103～105MPN·g-1(以污泥干重计)之间.MPN和qPCR检测结果之间的差异性显示厌氧消化会造成肠道病原菌的有活性但不可培养状态(VBNC),同时也提示应用传统的培养检测方法检测病原菌含量和评定污泥排放的生物安全性时需慎重.     

微波及其组合工艺强化污泥厌氧消化研究

为提高剩余污泥的厌氧消化效能和脱水性能,考察了微波及其组合污泥预处理工艺的强化污泥厌氧消化效果,同时考察了预处理-厌氧消化过程的污泥理化特征及其脱水性能.结果表明,微波及其组合工艺可以强化污泥厌氧消化产甲烷,其中微波-过氧化氢-碱(0.2)的强化效果最为显著,不仅30 d累计产甲烷量比对照组增加了13.34%,而且产甲烷速率也得到了提升.与单独微波处理相比,过氧化氢、碱的投加显著提高了溶解性COD的释放量,这表明微波、过氧化氢、碱之间的协同作用能有效破碎污泥,进而强化厌氧消化效果;微波-酸预处理后的污泥具有良好的脱水性能,毛细吸水时间(CST)只有9.85 s,污泥脱水性能的改善与其表面电性、粒径分布的变化密切相关;不同预处理条件下的污泥经过厌氧消化后,污泥脱水性能较为接近.