不同pH条件下剩余污泥厌氧发酵过程中溶出物的释放

对剩余污泥进行厌氧发酵处理可实现污泥中有机质和磷的释放并最终回收利用,而pH是影响厌氧发酵过程的重要因子。为研究pH对厌氧发酵中磷与有机物释放的影响,采用批次实验研究了pH分别为3、5、7、9、10、11时剩余污泥厌氧发酵过程中磷和有机物的释放与转化规律。结果表明,在不同pH下,剩余污泥厌氧发酵过程中发生着有机物与不同形态磷的迁移与转化,酸性和碱性环境下的厌氧发酵液成分的三维荧光结构不同。剩余污泥厌氧发酵过程中,泥相钙结合态磷(AP)在酸性条件下转化为液相磷,有机磷(OP)和大部分铁/铝结合态磷(NAIP)在碱性条件下转化为液相磷;其中, pH为11时,污泥发酵液中磷含量最高。污泥发酵类型为丁酸型发酵,发酵产物以异丁酸为主,其次是正戊酸和乙酸。pH为10时,发酵液中的蛋白质与多糖的总量、挥发性有机酸(VFAs)浓度最高,两者呈现正相关关系;类蛋白和类腐殖酸降解,利于VFAs的积累。     

pH对生物表面活性剂脂肽强化剩余污泥厌氧水解酸化的影响

近年来,污泥厌氧发酵作为一种新型的污泥处理方式受到广泛关注。通过厌氧发酵,一方面污泥得以减量化,另一方面,得到能源物质短链挥发性脂肪酸(SCFA)。然而,厌氧反应中水解步骤是限制污泥厌氧发酵的关键步骤。因此,提出利用脂肽强化污泥厌氧发酵生产SCFA的方法,并探讨了pH对脂肽强化污泥水解酸化的影响。实验结果表明,碱性环境有助于进一步提高脂肽作用下污泥厌氧水解酸化速率,且最佳pH为10,此时最大SCFA积累量为286.4 mg·g~(-1)。研究表明,碱性环境能够进一步强化污泥中有机物(蛋白质和多糖)的溶出,且抑制甲烷的积累。     

响应面法优化香蕉秸秆与猪粪混合厌氧发酵工艺研究

将香蕉秸秆与猪粪混合后厌氧发酵,考察粪秸比(猪粪干物质占发酵原料干物质的质量分数)、厌氧污泥接种量(厌氧污泥占发酵料液的质量分数)和发酵温度对总产气量的影响。在此基础上,通过响应面法对厌氧发酵工艺进行优化,并建立总产气量与粪秸比、厌氧污泥接种量、发酵温度的二次回归模型。研究结果表明,建立的二次多项式数学模型具有高度显著性,模型拟合度、精确度高,数据合理。最佳工艺条件为:粪秸比为35.34%,厌氧污泥接种量为61.40%,发酵温度为40.27℃。在此条件下,总产气量的预测值为15 779.2mL,试验值为15 620.5mL,二者相对偏差为1.01%。可见,所得模型能够较好地优化发酵条件并预测总产气量,可为提高香蕉秸秆与猪粪混合厌氧发酵产气量及提高发酵效率提供一定参考。     

不同来源污泥接种餐厨垃圾厌氧发酵产氢效果研究

在相同接种配比(接种污泥占餐厨垃圾的质量分数为30%)条件下,研究了4种不同来源污泥(压滤污泥、厌氧污泥、曝气污泥和河底淤泥)添加或不添加缓冲剂时对餐厨垃圾厌氧发酵产氢效果的影响.结果发现,在不添加缓冲剂时.4种污泥接种餐厨垃圾厌氧发酵平均产氢量依次为厌氧污泥>河底淤泥>压滤污泥>曝气污泥,接种厌氧污泥的餐厨垃圾平均产氢量最高,达10.11mL(以每克挥发性固体(VS)计,下同);而添加缓冲剂时.4种污泥接种餐厨垃圾厌氧发酵平均产氢量依次为厌氧污泥>曝气污泥>压滤污泥>河底淤泥,接种厌氧污泥的餐厨垃圾平均产氢量也最高,为33.72 mL,且体系pH得以缓冲.     

pH值对污泥发酵产酸的影响

利用剩余污泥厌氧发酵产生挥发性脂肪酸,可作为污水脱氮除磷的有机碳源,而pH值是发酵产酸过程中重要的控制参数.研究了不同pH值条件下剩余污泥厌氧发酵产酸过程中各参数变化规律,探索pH值对其过程的影响及其分析.结果表明,碱性条件有利于污泥发酵产酸过程,实验最佳条件是控制反应初始pH值为10.0,仅8d发酵挥发性脂肪酸浓度就达到8.90 mmol/L.此外,污泥在发酵过程中,酸性条件下NH4+-N和PO43--P的释放量均大于碱性条件.     

超磁分离污泥与剩余污泥协同水解酸化

以超磁分离污泥作为研究对象,用2种不同的剩余污泥作为接种污泥,维持温度在30℃,探究了剩余污泥对超磁分离污泥厌氧水解酸化产物及产率的影响。结果表明:随着剩余污泥接种量的增加,混合污泥SCOD的析出量也逐渐增加;接种剩余污泥量的增加促进了混合污泥VFAs的生成;各种污泥产VFAs中,乙酸均具有明显优势,并会促进丙酸的累积;混合污泥较之于超磁分离和剩余污泥具有快速、高效的产酸优势,且随着剩余污泥接种量的增加,加快了水解酸化的速率并且加深了酸化的程度,但会延长其达到最大值的时间。污泥产酸发酵获得内碳源的同时,还存在着N元素的释放,且随着剩余污泥接种量的增加,这种伴随现象更明显。对比2种剩余污泥(W1、W2)发现,W1作为接种污泥时,并没有明显的P元素的释放;当W2作为接种污泥时,伴随着比较明显的P元素的释放。综合考虑剩余污泥对于超磁分离污泥水解酸化效果的影响发现,当剩余污泥接种量W1为12.2%,W2为13.6%时,既可以为系统提供更多的SCOD,又可以避免过高的氮负荷。     

pH对混合污泥水解酸化的影响

pH对剩余污泥和初沉污泥水解酸化的影响已有报道,但pH对混合污泥水解酸化的影响尚鲜见报道。为此对厌氧环境,(20±1)℃,pH=4～11以及不控制pH条件下混合污泥的水解酸化特征进行了研究。研究发现:对pH调控有利于污泥SCOD的溶出,在较强的碱性条件下污泥溶出的SCOD要大于其他条件下的,特别是pH=10和11条件下污泥溶出的SCOD要远高于其他条件下。碱性环境和酸性环境以及中性环境相比更有利于混合污泥产酸,最佳产酸pH条件为pH=10。在酸性和极端碱性条件下均有利于混合污泥中氨氮和磷的释放。碱性环境利于挥发性悬浮固体(VSS)的去除,但不利于总悬浮固体(TSS)的去除。在不同pH条件下将混合污泥的发酵特征和剩余污泥和初沉污泥发酵特征比较,发现3种污泥水解和产酸均在碱性条件下最好,且在20～22℃的条件下,产酸量均在pH=10的条件下达到最大。     

蓝藻与污泥混合厌氧发酵产沼气的初步研究

为了实现太湖蓝藻打捞后的快速处置，对厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合厌氧发酵产沼气进行了研究。结果表明，蓝藻与污泥混合可以有效促进沼气发酵。在蓝藻与厌氧颗粒污泥物料比为6∶1时，产气效果最佳，沼气产率为73 mL/g VS，平均甲烷含量为69%，最大产气速率为138 mL/d，累计产甲烷量为50 mL CH₄/g干物质，分别是蓝藻与消化污泥、剩余污泥混合发酵时的1.5倍和2.3倍。厌氧颗粒污泥、消化污泥、剩余污泥与蓝藻混合，其VS降解率为11.40%～13.73 %，COD减少了27.97%～46.38%。厌氧发酵对蓝藻藻毒素的含量有较大影响，分别从356、366和244 μg/L降低到检测限5 μg/L 以下。     

水解酸化应用于剩余污泥减量的试验研究

碱减量印染废水生物处理剩余污泥接种培养成熟的水解酸化菌,通过它们的新陈代谢作用,可以实现系统内生命物质的更新和减量,同时降解了污泥吸附的有机物等,达到对剩余污泥减量的目的.在系统污泥减量初期,水解酸化作用对微生物的"液化"、内容物释放和对有机物的生物降解作用是污泥减量的主要原因;随着中间代谢产物的积累,微生物活性受到抑制,试验后期剩余污泥减量主要是微生物内源呼吸的结果.试验条件下,接种了成熟水解酸化细菌的 2 组剩余污泥 MLSS 浓度分别为 7.765 和 11.250 g/L,MLVSS 浓度分别为 4.466和 6.360 g/L,经过 513 h后 MLSS、MLVSS 浓度较开始时分别下降了 40.31%、45.73%和 54.85%、63.18%.一定污泥浓度范围,污泥减量效果与污泥浓度正相关.     

添加餐厨油脂对高含固污泥热水解及厌氧消化的影响

针对高含固污泥热水解传热差的问题,通过向剩余污泥中添加餐厨油脂协同污泥热水解以达到加速热水解过程的目的,探究了热水解时间和油脂添加量对污泥有机物水解及中温(35±1)℃厌氧消化性能的影响。结果表明:油脂与污泥协同热水解可有效促进污泥中不溶态有机物的水解,当热水解温度为165℃、水解时间为90 min时,油脂与污泥的质量比为0.4∶1时,有机物水解效果最佳;添加油脂能提高热水解速率,当油脂与污泥的质量比分别为0.2∶1、 0.4∶1、 0.6∶1时,污泥中不溶态有机物的水解速率分别提高了23.30%、 43.63%和62.98%;油脂的添加可提高甲烷产量和产甲烷速率,但会延长延滞期,综合考虑热水解与厌氧消化的性能,建议预处理时间为90 min、油脂与污泥的质量比为0.2∶1为最佳条件。添加餐厨油脂可加速高含固污泥的热水解过程,有助于实现污泥的高效处理。     

剩余污泥发酵产酸特征及基质释放规律研究

剩余污泥发酵既能实现污泥减量,又能获得污水生物脱氮除磷所需的挥发性脂肪酸VFAs等。采用序批式污泥发酵实验,在(30±1)℃的条件下,研究剩余污泥投配比对序批式污泥发酵系统污泥减量、产酸以及基质释放过程的影响,探索VFAs生成最大化的条件。实验结果表明:投加接种污泥不能明显提高序批式污泥发酵系统剩余污泥的减量效果,但可以改善污泥的产酸特性;当污泥投配比大于50%时,发酵过程中将出现2个VFAs浓度峰,且第二次峰浓度更大;较为理想的序批式污泥发酵投配比是60%~80%、发酵时间为5 d或25 d,前者VFAs表观转化率最大(约24%),后者发酵液中VFAs浓度最高(约600 mg/L);发酵过程中,NH4+-N总体呈上升趋势,磷浓度发酵5 d时达到最大值。     

Ozone pre-treatment as improver of PAH removal during anaerobic digestion of urban sludge

Polycyclic aromatic hydrocarbons are ubiquitous persistent pollutants. They may accumulate in sludge during wastewater treatment because of their low biodegradability and their hydrophobic characteristics. Combination of ozonation and anaerobic digestion may be efficient to remove PAHs naturally present in sludge. The objective of this study was to investigate the impact of ozone pre-treatment, with and without surfactant addition, on the anaerobic degradation of 12 PAHs (from low to high molecular weight). Under anaerobic digestion without ozonation pre-treatment, the highest removals were obtained for the lightest PAHs (3-aromatic rings). Ozonation pre-treatment of sludge allowed to increase biodegradability or bioavailability of each PAH, and the PAH removals were well correlated to the PAH solubility. Finally, addition of tyloxapol before sludge ozone pre-treatment had antagonist effects on PAH removal during anaerobic digestion: negative impact on anaerobic ecosystem activity and improvement of PAH bioaccessibility (particularly the PAHs with the highest octanol water partition coefficients).     

厌氧-立体循环一体化氧化沟除磷脱氮工艺中影响厌氧释磷的因素研究

本研究考察了厌氧-立体循环一体化氧化沟工艺(AN-IODVC)中厌氧释磷效果及诸影响因素.研究结果表明,AN-IODVC除磷脱氮系统中好氧污泥的VSS/MLSS值比厌氧污泥小,好氧污泥含磷量与厌氧污泥含磷量的差值和TP去除率、厌氧磷释放率及厌氧ORP呈良好的线性相关关系.厌氧磷释放的最佳条件为:污水COD/TP＞55,维持厌氧区ORP低于-400mV.     

Phosphorus release in aerobic sludge digestion.

The objectives of this study are to examine the phosphorus release in aerobic sludge digestion and to better understand its governing mechanisms. In this study, phosphorus release was examined using the secondary sludge from both conventional and biological nutrient removal processes. The experiments were carried out at room temperature (22 +/- 2 degrees C), with or without automatic control of pH (4.5 to 7.8), and under three aeration schemes: fully aerobic (dissolved oxygen [DO] at 3 to 4 mg/L), low DO (0.2 to 0.8 mg/L), and cyclic (with alternate on/off aeration). The released phosphorus concentrations were 20 to 80 mg/L for the conventional sludge and 60 to 130 mg/L for the biophosphorus sludge. Higher phosphorus release also occurred at low pH (<6.0). As for the effect of DO, fully aerobic digestion caused higher phosphorus release than the low-DO and cyclic operations. For better understanding, the solid phosphorus in sludge was conceptually categorized into three forms: inorganic phosphorus precipitates, organic cellular phosphorus, and polyphosphate (poly-P) in polyphosphate-accumulating organisms. Dissolution of inorganic phosphorus precipitates is controlled by physical and chemical conditions, with pH being the most important in this study. Lowering the pH to 4 to 6 clearly promoted the release of inorganic phosphorus. Polyphosphate hydrolysis, on the other hand, was found to be regulated biologically (sensitive to occurrence of anaerobic conditions) and was insignificant in the glutaraldehyde-fixed sludge. Phosphorus release from organic phosphorus should correlate with the volatile solid (VS) digestion, which lyses the cells and frees the phosphorus covalently bonded with the organic matters. The amounts of phosphorus released per unit VS digested (deltaP/deltaVS) were therefore calculated for experiments with long periods of constant pH (to minimize interferences from dissolution/precipitation of inorganic phosphorus). The results suggested that some poly-P was hydrolyzed and released accompanying the aerobic VS digestion, but at rates far lower than those under anaerobic conditions.     

培养方式对废水脱氮与沼气脱硫污泥驯化影响

实验研究了底物、接种污泥和微生物生长方式对猪场废水脱氮和沼气脱硫耦联污泥驯化及活性恢复的影响,以解决快速富集培养废水脱氮与沼气脱硫微生物的问题。研究发现,就脱氮脱硫均达到60%的时间而言,接种厌氧污泥反应器为9 d,比接种好氧污泥反应器(18 d)和不接种污泥加填料反应器(21 d)更短。以含氮含硫废水为底物驯化时,接种厌氧污泥更有利于脱氮脱硫污泥的驯化;而同为接种好氧污泥时,以含氮含硫废水为底物的驯化方式更有利于脱氮脱硫污泥的驯化。污泥活性恢复实验中,以含氮废水+沼气(H2S)为底物培养驯化的污泥,硫转化活性恢复所用的时间为15 d,比含氮含硫废水为底物驯化污泥的活性恢复时间更长。     

3种污泥对磺胺二甲基嘧啶的吸附性能

研究了厌氧颗粒污泥、厌氧污泥及好氧污泥对磺胺二甲基嘧啶(SM2)的吸附性能。当SM2初始浓度为50μg/L时,采用活性污泥灭活吸附,考察了吸附平衡时间、吸附等温线及温度对污泥吸附的影响,并比较了失活污泥与活性污泥的吸附性能。结果表明,3种污泥对SM2的吸附均在1 h内达到吸附平衡;3种失活污泥对SM2的吸附都可用Freundl-ich和Langmuir吸附模型来描述,并且Freundlich吸附模型的拟合效果要好于Langmuir模型(R2F>R2L);温度对3种污泥吸附影响规律一致,并且吸附常数KF(15℃)>KF(25℃)>KF(35℃),这说明吸附为放热反应,低温有利于吸附反应的进行。活性污泥对SM2的吸附与失活污泥吸附规律一致,都符合Freundlich模型。3种活性污泥对SM2的去除是吸附和降解的共同作用,并且都是降解占主导地位,降解效率为厌氧污泥>好氧污泥>厌氧颗粒污泥。     

催化铁与生物法耦合除磷工艺特性

为了研究催化铁与生物耦合后对生物除磷特性的影响，实验采用人工配水用厌氧／好氧间歇流式富集培养聚磷微生物。对比发现，催化铁与生物耦合组中厌氧末段ORP降低了约60mV，pH值小幅度的上升（≤0．3），整个培养过程中铁离子的浓度开始快速增加，之后趋于稳定（约40mgFe／gMLSS）。对好氧末段污泥SVI值比较发现，耦合工艺污泥沉降性能得到改善。除磷曲线比较发现，耦合组中厌氧末段磷的释放量下降，而好氧阶段磷的吸收速率增加；胞内聚合物提取表明，耦合组厌氧末段聚磷菌细胞内PHA含量有提高，好氧末段糖原含量有下降。磷形态提取分析表明，耦合组好氧末段污泥中无机态PO3 4-- P含量更高。低浓度铁离子可以起到与生物耦合同步除磷的目的，本工艺长期运行未发现耦合体系中催化铁对除磷的抑制作用。     

臭氧预处理—厌氧消化工艺促进剩余污泥减量化的研究

主要研究了臭氧氧化对剩余污泥的破解效果及污泥厌氧消化效率的影响.结果表明,随着臭氧投加量的增加,悬浮物(SS)、可挥发性悬浮物(VSS)逐步减少,而剩余污泥上清液中的溶解性COD(SCOD)、总有机碳(TOC)、蛋白质和多糖则明显增加.经臭氧预处理(臭氧投加量为0.050 g(以每克SS计))后,剩余污泥中温(35℃)厌氧消化效率明显提高,经65d稳定运行后,总挥发性固体(TVS)去除率为67.58％,与未经臭氧预处理的剩余污泥相比提高50.61％;甲烷平均产率为0.303 L(以每克TVS计),与未经臭氧预处理的剩余污泥相比提高54.59％.可见,臭氧预处理能有效促进污泥厌氧消化,从而达到污泥减量的目的.     

Effects of reduced return activated sludge flows and volume on anaerobic zone performance for a septic wastewater biological phosphorus removal system.

Enhanced biological phosphorous removal (EBPR) performance was found to be adequate with reduced return-activated sludge (RAS) flows (50% of available RAS) to the anaerobic tank and smaller-than-typical anaerobic zone volume (1.08 hours hydraulic retention time [HRT]). Three identical parallel biological nutrient removal pilot plants were fed with strong, highly fermented (160 mg/L volatile fatty acids [VFAs]), domestic and industrial wastewater from a full-scale wastewater treatment facility. The pilot plants were operated at 100, 50, 40, and 25% RAS (percent of available RAS) flows to the anaerobic tank, with the remaining RAS to the anoxic tank. In addition, varying anaerobic HRT (1.08 and 1.5 hours) and increased hydraulic loading (35% increase) were examined. The study was divided into four phases, and the effect of these process variations on EBPR were studied by having one different variable between two identical systems. The most significant conclusion was that returning part of the RAS to the anaerobic zone did not decrease EBPR performance; instead, it changed the location of phosphorous release and uptake. Bringing less RAS to the anaerobic and more to the anoxic tank decreased anaerobic phosphorus release and increased anoxic phosphorus release (or decreased anoxic phosphorus uptake). Equally important is that, with VFA-rich influent wastewater, excessive anaerobic volume was shown to hurt overall phosphorus removal, even when it resulted in increased anaerobic phosphorus release.     

Biological phosphate uptake and release: effect of pH and magnesium ions.

Enhanced biological phosphorus removal (EBPR) is based on poly-phosphate accumulating organisms' (PAOs) unique features of "luxury" phosphate uptake during aerobic conditions and phosphate release in anaerobic conditions. It is believed that poly-phosphate accumulation is accompanied by the uptake and accumulation of potassium ions (K+) and magnesium ions (Mg2+). The release of phosphate under anaerobic conditions is also accompanied by the release of both cations. The objective of this research was to evaluate the effect of pH and Mg2+ on the biological phosphate uptake and release behavior of activated sludge mixed liquor during aeration and sedimentation. Research results indicate that Mg2+, supplied either by magnesium chloride (MgCl2) or magnesium hydroxide [Mg(OH)2], stimulated phosphate uptake during the aeration period, while pH increase, caused by the application of Mg(OH)2, enhanced phosphate release during the sedimentation period. It is also noted in our experiments with MgCl2 that Mg2+ slightly inhibited anaerobic phosphate release.