剩余污泥混合对絮凝污泥厌氧消化的强化

为了考察絮凝污泥与剩余活性污泥混合中温(35℃)厌氧消化效果,分析了不同混合比例、不同投配率下的总化学需氧量(TCOD)去除率、挥发性固体(VS)降解效果,通过pH值与氨氮浓度的变化来分析各反应器的稳定性。结果表明:污泥混合后消化效果明显得到提高,且污泥消化效率随着投配率的增加先提高后下降。5%投配率时,絮凝污泥/剩余污泥(VS比)为1:2时厌氧消化效果最好,TCOD去除率达到47.8%,VS降解率达到46.8%,分解单位VS产气量达到了435 mL/g,pH值与氨氮浓度分别保持在7.4和269 mg/L左右,混合污泥厌氧消化系统较稳定。这说明与剩余污泥的混合消化能有效提高絮凝污泥的厌氧消化性能。污泥絮体的显微分析表明:厌氧消化过程中絮体面积百分比逐步减小,污泥结构逐步解体,可以解释污泥消化的微观过程。     

电化学预处理提高剩余污泥好氧消化性能研究

采用电化学方法对好氧消化处理前的剩余污泥(以下简称污泥)进行预处理,考察了不同预处理条件对污泥有机物(以MLVSS来表征)的去除效果,探讨了电化学预处理对污泥好氧消化效率的影响。结果表明,以网状钛涂钌电极板为电极,在pH为11.00,极板间距为2.0cm,工作电压为15V,气体搅拌作用下电解30min后,污泥(初始质量浓度为20.04g/L)的MLVSS去除率达9.7%。污泥经过电化学预处理后,在自然温度(10～15℃)下进行好氧消化处理,14d后MLVSS去除率达40.1%,而同期未经预处理的污泥MLVSS去除率为33.2%,并于20d后达40.2%。经电化学预处理后污泥的好氧消化效率显著提高,大大缩短了污泥好氧消化的时间。     

Enhancement of batch waste activated sludge digestion by microwave pretreatment.

Batch anaerobic digesters were used to stabilize microwave (MW)-irradiated waste activated sludge (WAS). A low temperature range (50-96 degrees C) MW irradiation was applied. Effects of pretreatment temperature (T) and intensity (I), concentration (C) and percentage of sludge pretreated (PT) were investigated in a multilevel factorial statistical design containing 54 mesophilic batch reactors by monitoring cumulative biogas production (CBP). Variance analysis (ANOVA) determined that the most important factors affecting WAS solubilization were temperature, intensity, and sludge concentration. Improvements in CBP from WAS were significantly affected by sludge percentage pretreated, temperature, and concentration. Pretreatment resulted in 3.6 +/- 0.6 and 3.2 +/- 0.1 fold increases in soluble to total chemical oxygen demand (SCOD/TCOD) at high and low sludge concentrations, respectively. WAS, microwaved to 96 degrees C, produced the greatest improvement in CBP with 15 +/- 0.5 and 20 +/- 0.3% increases over controls after 19 d of digestion at low and high WAS concentrations. Dewaterability of microwaved sludge was enhanced after anaerobic digestion.     

超声波联合厌氧消化处理制药污泥

以制药废水处理厂污泥为研究对象,采用超声波技术研究了污泥破解过程中污泥溶解性、沉降性、温度pH和粒径分布等变化情况,以及超声预处理对污泥后续厌氧消化的影响。研究结果表明,超声波能强化污泥的溶解性,在超声比能耗0到250000 kJ/kgTS范围内,污泥上清液的SCOD、TOC、TN和TP值均大幅增加,当比能耗相同时,高能短时的超声条件更利于污泥破解;污泥经超声波处理后,温度上升至40~52℃,pH值在6.9±0.2范围内有所波动,体积平均粒径削减58.75%~72.81%,污泥沉降比SV30由35%急剧升高至95%左右,使脱水性能变差。经ES 250000 kJ/kg TS的超声预处理,污泥厌氧消化的甲烷产量提高了36.81%,VS去除率由33.89%提高到53.11%,TCOD去除率由16.65%提高到89.23%,促进了污泥厌氧消化的产气效率和减量化效果。     

超声与次氯酸钠耦合预处理剩余污泥的中温厌氧消化效果

以某城市污水处理厂剩余污泥为对象,通过实验研究了超声与次氯酸钠预处理对污泥的溶胞效果,以及对后续厌氧消化的影响。结果表明,超声与次氯酸钠耦合作用最优操作条件为超声声能密度1.0 W/mL,作用时间50 min。在此条件下,次氯酸钠投加量为4.023 mg/g SS时,对污泥厌氧消化改善效果最明显,剩余污泥产气率及甲烷含量较对照组分别提高了69.73%和10%。同时污泥VSS去除率由11.11%提高到21.24%,在一定程度上实现了污泥减量。     

污泥加热预处理对中温厌氧消化的影响

对污泥加热预处理给中温厌氧混合消化和污泥单独消化带来的影响进行了研究.研究结果表明,污泥加热预处理有利于提高混合消化对 COD 的去除率,尤其是 SCOD 的去除率由 77%增长到 93%,但不利于 TS 和 VS 的去除;而对污泥单独消化,预处理则不利于有机物的去除.采用加热预处理后的污泥进样,混合消化和污泥单独消化的甲烷产气量均有所提高.     

低强度超声波强化剩余活性污泥好氧消化的研究

污泥是城市污水处理厂的副产物,若处理不当,将会带来一系列严重的环境问题.实验采用低强度超声波对剩余活性污泥(WAS)的好氧消化过程进行强化,选取超声强度、超声时间、超声间隔3个因素设计正交实验.结果表明,经超声辐照的WAS,其好氧消化时间最短仅约为13 d,比未经超声辐照的缩短了18.00 d.对实验结果的极差分析和方差分析表明,低强度超声波强化WAS好氧消化的最佳参数为:超声强度1.0 W/cm2、超声时间10 min、超声间隔8 h.实验还研究了WAS达标前后溶解性化学需氧量(SCOD)和总化学需氧量(TCOD)的变化情况,发现在相对较短的处理时间内,经低强度超声波强化处理的WAS的TCOD降解率仍然能与对照相近甚至高于对照,主要原因是低强度超声波强化了微生物的新陈代谢,促进了其对有机物的吸收分解.     

土霉素对剩余污泥中温厌氧消化的短期和长期影响

在中温(35℃)条件下,考察了土霉素(OTC)对剩余污泥厌氧消化的短期和长期影响。在短期影响实验中,采用间歇实验装置研究了OTC浓度为5、50和500 mg/L时对累计甲烷产气量的影响。结果表明,50 mg/L的OTC短期暴露下中温厌氧消化污泥的产甲烷活性会受到急性抑制,但经过141 h的驯化后系统能够恢复产气,表明中温厌氧污泥经过驯化后,可处理含高浓度OTC的剩余污泥。采用完全混合反应器进行了为期230 d的OTC长期影响实验,反应器进泥中OTC浓度从0 mg/L逐步提高为40、200和1 000 mg/L,通过定期监测产气量、甲烷含量和挥发性脂肪酸等指标来表征反应器的运行状况。当OTC浓度≤200 mg/L时系统产气量和气体中甲烷含量稳定并且消化液中挥发性脂肪酸未出现累积,表明厌氧系统未受到影响。但在OTC浓度为1 000 mg/L时运行43 d(2个污泥停留时间)后,污泥中发酵产酸细菌类群代谢活性受到抑制,导致系统产气量下降。上述结果表明,经过驯化,中温厌氧消化系统可处理OTC浓度≤200 mg/L的剩余污泥。     

碱解+低温水热预处理改善剩余污泥中温厌氧消化性能工艺

以城市污水厂剩余活性污泥为对象,研究在不同碱解药剂和剂量以及不同水热预处理温度和水热时间下"碱解+低温水热预处理"的破胞效果。通过对预处理泥样进行中温((35±1)℃)厌氧消化生物化学甲烷势(biochemical methane potential,BMP)实验来评价该预处理工艺对中温厌氧消化性能的影响。实验结果表明,SCOD的溶出效果及VSS的减量化程度随着加碱剂量、水热温度的增加而呈现先升高后略有下降的趋势,且在碱解条件为0.05 g NaOH/g TS和水热条件为70℃、9 h时的预处理条件下破胞效果最为显著;在该预处理条件下,SCOD的溶出率可达52.3%,VSS的降解率达到33.3%。BMP实验结果显示,在最佳预处理条件下,与对照组相比,TCOD去除率提高了77.1%,甲烷产气量是对照组的2.7倍,甲烷产气率可达354 mL CH4/g VS。     

氧氟沙星与聚苯乙烯微塑料复合污染对剩余污泥厌氧消化的影响

为探究抗生素与微塑料复合污染对厌氧消化的作用影响,采用BMP实验考察了不同质量浓度氧氟沙星(OFL)、聚苯乙烯(PS)微塑料对剩余污泥厌氧消化产甲烷的影响行为,并通过分析溶解性有机物(DOM)、胞外聚合物(EPS)变化规律、厌氧发酵4阶段代谢以及微生物群落探讨其影响机理。结果表明,与对照组相比,单一OFL和单一PS微塑料污染使甲烷累积产量分别下降了15.95%~81.36%、4.25%~5.78%;而在复合条件下,两者表现出协同效应,故导致产甲烷速率的进一步下降和有效产气时间的缩短,其中OFL胁迫占主导。机理探究发现,不论单一OFL还是复合污染,DOM中腐殖质类物质均明显增加,EPS组分结构趋于复杂化,厌氧消化4阶段均受到明显抑制。单一PS微塑料污染在反应初期可提高产甲烷速率,且对厌氧消化4阶段的影响相对较小。微生物群落分析发现,复合组与单一OFL组群落分布更为相近,产酸细菌与嗜乙酸产甲烷菌的相对丰度均明显下降,这导致乙酸营养型产甲烷途径受到严重抑制。本研究结果可为复杂污染情况下剩余污泥资源化处理的工艺调控提供参考。     

Anaerobic digestion of thermo-oxidized excess municipal sludge.

The effect of a thermo-oxidative co-treatment placed between the two reactors of two-stage anaerobic digestion of excess municipal sludge was studied. The oxidant used was hydrogen peroxide (H2O2), and moderate temperatures below the boiling point of water were considered. The first experiment was to elucidate the effect of two different temperatures (65 and 90 degrees C) of oxidation using a constant oxidant dose of 1.0 g H2O2/g influent volatile suspended solids (VSSinfluent). The use of thermo-oxidative co-treatment increased overall solids destruction by 24.9 and 33.5%, respectively, when operating at 65 and 90 degrees C, respectively. Because of this significant effect of temperature on the performance of the process, a second experiment was conducted using the higher temperature of 90 degrees C while decreasing the hydrogen peroxide dosage to 0.5, 0.25, and 0.1 g H2O2/g VSSinfluent. An increase in solids destruction of 13.9, 18.9, and 25.6% was observed when the thermo-oxidative co-treatment was used using oxidant dosages of 0.1, 0.25, and 0.5 g H2O2/g VSSinfluent, respectively.     

超声联合碱解预处理对剩余污泥破解和厌氧消化的影响

对比研究了单独超声、单独碱解和两者联合预处理对污泥破解和厌氧消化性能的影响。以加碱量和输入能量为控制参数,研究了不同条件下的污泥破解和有机物溶解变化。结果表明：联合预处理技术对污泥破解和有机质溶解的效果比超声和碱解单独作用之和更好。污泥破解增加值ΔSCOD/TCOD和加碱量之间存在显著的线性关系（R2=0.936）。超声和碱解联合预处理对污泥厌氧消化产甲烷量较原泥增加了16.57%~31.13%。厌氧消化产甲烷结果表明,SCOD/TCOD的增加并不总是促进厌氧消化性能的改善,二者之间存在二次非线性关系（R2=0.85）,且厌氧消化性能最高点出现在超声能量12 000 kJ·kg-1（TS）、加碱量0.08 g·g-1（TS）联合作用条件下。     

Comparison of mechanical pretreatment methods for the enhancement of anaerobic digestion of pulp and paper waste activated sludge

The conventional anaerobic digestion process, requiring long solids retention times (SRTs) to digest solids, is currently viewed as impractical for the pulp and paper industry because of high capital costs associated with the construction of new digesters. Recent developments in sludge solubilization technology could be promising in reducing digester size, which also allows for the potential use of decommissioned tanks, both of which can reduce the capital cost. Three pretreatment technologies for use with anaerobic digestion were tested on laboratory-scale to investigate their feasibility. The SRTs in all three digesters systematically decreased from 20 to 3 days. The reference digester was fed waste activated sludge (WAS) to serve as the control at the same SRTs. The other digesters were fed WAS that had been preconditioned using mechanical shearing, sonication, or high-pressure homogenization technology. Anaerobic digestion with high-pressure homogenization produced as much methane at 3-day mean SRT as that from the reference digester operated at 20-day SRT. Therefore, a new digester can theoretically be 85% smaller than a conventional digester. An added benefit of WAS to methane conversion is the recovery of nutrients nitrogen and phosphorus.     

污泥投配率对污泥中温厌氧消化效果影响的试验研究

试验装置采用半连续流污泥中温厌氧消化反应器,污泥培养接近成熟后开始每天按不同污泥投配率加泥和排泥.结果表明:污泥投配率在3%～10%时,有机物分解率先增大后减小,去除率均在30%以上;污泥投配率在15%和20%时,污泥的有机物去除率非常小;污泥投配率在5%时,有机物分解率最大为41.2%;单位VSS产气量随污泥投配率的增大而呈先急剧上升后逐渐下降的趋势,当污泥投配率为5%时,单位VSS产气量为0.60 L/g,符合美国污水处理厂设计手册标准,其他污泥投配率下该指标均小于0.4 L/g.因此,认为实验用污泥中温消化的最佳污泥投配率为5%,这时污泥的可消化性较好.     

浮萍与剩余污泥厌氧消化产沼气实验

为了提高浮萍厌氧消化产沼气能力,对比浮萍和剩余污泥的单独以及混合厌氧消化过程的产气情况,得到当两种底物混合厌氧消化时,具有互补优势,缩短了产甲烷过程的酸化期,累积产气量实际值比计算值提高11%。此外,研究底物的预处理以及底物与接种物比例对厌氧过程的影响,结果表明,浮萍经热碱预处理后比未处理组甲烷产量增加了8%,且厌氧消化产沼气时间缩短;当底物与接种物比例为1：1时,整个反应过程的pH维持在6.00以上,利于产甲烷过程,体系中积累的挥发性脂肪酸（VFAS）最多,且获得的总沼气产量和总甲烷产量最大,分别为3 309 mL和1 883 mL,比最低的1：2.5组分别高出151 mL和304 mL。     

酸处理对活性污泥脱水性能的影响及其作用机理

用硫酸对活性污泥进行脱水前预处理,可使污泥中水分分布发生有利于机械脱水的变化,即结合水含量减少、可脱水程度增大,从而改善活性污泥脱水效果.试验数据表明,只加阳离子PAM调理,污泥经过板框压滤脱水后(压榨时间30 min)泥饼含水率为76.14%;经过酸化预处理后再加阳离子PAM可以使泥饼含水率降至70.24%.不管是过滤脱水还是离心脱水过程,酸处理对污泥脱水速率没有太大影响,却可以提高污泥可脱水程度.进一步研究发现,酸处理的机理是:酸处理使污泥中胞外聚合物ECP水解、微生物细胞瓦解,从而絮体内部间隙水、细胞内部间隙水被释放变成自由水,污泥水分分布发生变化,污泥可脱水程度提高,最终导致污泥脱水效果好.     

Copper (II) adsorption by the extracellular polymeric substance extracted from waste activated sludge after short-time aerobic digestion

The extracellular polymeric substance (EPS) extracted from waste activated sludge (WAS) after short-time aerobic digestion was investigated to be used as a novel biosorbent for Cu²⁺ removal from water. The EPS consisted of protein (52.6 %, w/w), polysaccharide (30.7 %, w/w), and nucleic acid (16.7 %, w/w). Short-time aerobic digestion process of WAS for about 4 h promoted the productivity growth of the EPS for about 10 %. With a molecular weight of about 1.9?×?10⁶ Da, the EPS showed a linear structure with long chains, and contained carboxyl, hydroxyl, and amino groups. The sorption kinetics was well fit for the pseudo-second-order model, and the maximum sorption capacity of the EPS (700.3 mg Cu²⁺/g EPS) was markedly greater than those of the reported biosorbents. Both Langmuir model and Freundlich model commendably described the sorption isotherm. The Gibbs free energy analysis of the adsorption showed that the sorption process was feasible and spontaneous. According to the complex results of multiple analytical techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy, etc., the adsorption process took place via both physical and chemical sorption, but the electrostatic interaction between sorption sites with the functional groups and Cu²⁺ is the major mechanism.     

剩余活性污泥好氧消化优势菌株筛选及污泥稳定化效果分析

为了促进污水处理厂剩余污泥好氧消化效率,缩短污泥稳定化时间,筛选得到R3、R16、R19等3株对污泥好氧消化促进效果较为明显的优势菌种,通过16S rRNA基因序列分析表明,R3、R16、R19分别属于Bacillus sp.、Pseudomonas sp.和Bacillus sp.。研究结果表明：投加R3、R16、R19菌株,分别于第9天、第10天、第9天污泥达到消化稳定化状态,TOC降解率达到40%,比对照组分别提前了4、3、4 d,与对照组稳定化完成时的SVI相比,SVI值较对照组分别降低了14.1%、9.0%和11.1%。当消化反应进行到第13天时,投加R3、R16、R19菌株,MLSS降解率较对照组分别提高了7.1%、3.3%和8.2%。此外,投加优势菌株不同程度地加快了TOC、硝酸盐氮和氨氮在消化液中的积累,并且有利于磷的溶出。     

污泥炭强化微生物电解池提高污泥厌氧消化甲烷产率与系统稳定性

投加污泥炭可有效改善利用微生物电解池厌氧消化(MEC-AD)甲烷产率偏低的问题,但其对MEC-AD体系的长期影响仍未知。研究了不同运行条件(外加电压、有机负荷率OLR)下,污泥炭对MEC-AD在连续进料运行模式下产甲烷效能的提高。首先,基于甲烷产率、电流密度等指标,确定最佳外加电压为1.5 V;然后,在相同外加电压(1.5 V)、不同OLR的条件下,比较了对照组(ME1.5)和投加污泥炭的实验组(MEBC1.5)的产甲烷和系统稳定性,OLR通过水力停留时间(HRT)控制。结果表明,当HRT从10 d逐步缩短至2.5 d,ME1.5与MEBC1.5的甲烷产率呈现先上升后下降的变化趋势,且MEBC1.5的甲烷产率始终高于ME1.5。这表明污泥炭在不同OLR运行条件下均可改善甲烷产率。微生物群落多样性分析结果表明,对比ME1.5与MEBC1.5,投加污泥炭使得生物阴极优势菌属Coprothermobacter、Fervidobacterium、Bellilinea、Methanosarcina的相对丰度分别增加了34.1%、186.6%、130.5%、9.5%。KEGG通路分析结果表明,MEBC1.5中乙酸裂解途径和H₂还原CO₂途径产甲烷代谢过程相关基因的丰度均有所提高。本研究结果可为污泥炭强化市政污泥MEC-AD产甲烷效能和相关的微生物机制提供参考。