化学解偶联剂对A2/O工艺污泥产率的影响

通过试验比较了2,4-二硝基苯酚(DNP)、间氯苯酚(m-CP),2,4,5-三氯苯酚(TCP)和3,3',4',5-四氯水杨酰苯胺(TCS)这4种化学物质对A2/O工艺中污泥产率的影响.结果表明:4种化学物质均可作为解偶联剂,都能有效控制污泥产率.其中,TCP在减少污泥产率方面最为有效,且对工艺运行效能的影响较小,当其浓度为4mg/L时,污泥产率下降了53.07%,而系统对COD的去除率仅下降了 3.88%.除TCS外,其他3种解偶联剂均满足pKa值越低则污泥减量化效果越好这一规律.     

葡萄糖共基质下硝基酚产甲烷毒性研究

在中温（35℃）厌氧间歇试验条件下，以葡萄糖为共基质，通过测定累计产甲烷量，研究了3-硝基酚（3-NP）、2，4-二硝基酚（2，4-DNP）和2，6-二硝基酚（2，6-DNP）的厌氧毒性，并利用相对活性确定了反应时间为24、48、72和96h时3种硝基酚的50％相对抑制浓度。结果表明：当33N-P浓度≤40mg／L时，对产甲烷菌没有产生抑制，反而有促进作用；当浓度为80-160mg／L时产生轻度抑制；当浓度≥320mg／L时产生重度抑制。当32，4-DNP浓度≤10mg／L时，对产甲烷菌不产生抑制；当浓度≥20mg／L时产生重度抑制。当32，6-DNP浓度≤20mg／L时，对产甲烷菌不产生抑制；当浓度为40mg／L时产生轻度抑制；当浓度≥80mg／L时产生重度抑制。根据50％相对抑制浓度判断，3种硝基酚对产甲烷菌活性的抑制大小顺序为2，4-DNP〉2，6-DNP〉3-NP。     

不同污泥龄对活性污泥系统处理各种药物的影响

运行4个实验室规模(3 L)的序批式活性污泥反应器(SBR),其污泥龄(SRT)分别为2、8、14、20 d。批次摇瓶试验通过设置3个工况(正常运行、加入生物抑制剂、无微生物)来讨论5种污泥(4个SBR和当地污水处理厂)对浓度为5μg/L的10种药物的处理效果,以及在一个运行周期(8 h)中吸附作用、生物降解作用和挥发损失的去除贡献。试验结果显示,对乙酰氨基酚、咖啡因基本能被去除,去除率在60%以上,立痛定、磺胺甲恶唑能被部分去除,去除率为30%～55%;降固醇酸、林肯霉素、甲氧苄啶的处理效果不好,去除率<15%。在相同污泥浓度下进行的摇瓶试验结果表明,对4种磺胺类药物的去除率为20%～60%,磺胺甲恶唑、磺胺间二甲氧嘧啶、磺胺甲基嘧啶主要依靠吸附作用去除,磺胺嘧啶则是依靠生物降解作用去除。从单因素方差分析可知,对磺胺类药物的去除效果与污泥龄有着显著的关系(p<0.02)。     

污泥浓度与曝气强度对MBR运行的综合影响

高污泥浓度可以在减少剩余污泥产量的同时提高系统的容积负荷，但经济曝气强度随污泥浓度的增加呈指数递增，从而使能耗大大增加。为解决这一矛盾，进行了一体式A／O法膜生物反应器处理城市污水的试验，结果表明：过高或过低的污泥浓度和曝气强度都会影响膜生物反应器对COD、NH3-N、TN等污染物的去除效果，并且会加剧膜污染。膜生物反应器存在临界污泥浓度和经济曝气强度，在试验条件下分别为4．73g／L和451L／（m^2·h）。     

水解酸化/AAO工艺的同步脱氮除磷及污泥减量研究

针对传统活性污泥法脱氮除磷效率低、污泥产量高的缺点，提出了水解酸化／缺氧-厌氧-好氧（HAAO）污水、污泥一体化处理工艺，研究了该工艺去除COD、氮、磷和污泥减量的效果及其主要影响因素。试验结果表明，在进水COD为286-425mg／L、NH4^＋ -N为36-58mg／L、PO4^3- -P为4-12mg／L、总水力停留时间为11．5h及无外加碳源和碱度的条件下，系统对COD、NH4^＋ -N、TN、PO4^3- -P的去除率分别可达95％、98％、84％、87％。好氧段的DO浓度、固体停留时间（SRT）和剩余污泥回流比对系统的运行效果有重要影响。将污水和剩余污泥同时进行水解酸化，既可有效地改善污水的可生化性，提高系统对碳源的利用效率，又可实现污泥的减量化，试验条件下系统的污泥减量率达56．5％。     

活性污泥中提取的藻酸作为铜吸附剂的研究

采用实验室培养的活性污泥提取藻酸并制备藻酸钙吸附剂,用于去除污水中的Cu2+,考察了其吸附和解吸性能及影响因素,并采用城市污水处理厂的剩余污泥进行验证.结果表明:pH值和藻酸钙投量对其吸附Cu2+有明显影响,当pH值为4、Cu2+初始浓度为100 mg/L、藻酸钙投量为0.7 g/L时,对Cu2+的平衡吸附量为41.96 mg/g;藻酸钙对Cu2+的吸附过程符合Langmuir模型;以盐酸为解吸剂,藻酸钙的解吸率可达到90%.实际剩余污泥可制备(203±11)mg/g的藻酸钙,对Cu2+的吸附量可达51.44 mg/g,而解吸率可达到94%.采用剩余污泥制备藻酸钙吸附剂,操作简单、成本低、对Cu2+的吸附高效、易于再生,具有工业应用前景.     

改进污泥水解制取蛋白质工艺的研究

为改进污泥水解蛋白质的制取工艺,设计了正交试验来研究污泥水解的最佳反应条件,分析了污泥种类和形态对水解效果的影响,在此基础上提出了制取蛋白质的碱法循环水解工艺。结果表明,污泥水解的最佳条件是：固液比为1：2（每100g鲜泥加水200mL）,温度为121℃,石灰（25％）与NaOH（2％）配合催化;干污泥的水解效果好于鲜污泥,回流污泥的水解效果好于剩余污泥;碱法水解只需循环4次,便可使水解液的蛋白质浓度达到72．465g／L,符合实际生产的要求。     

啤酒污泥用作城市污水厂种泥的试验研究

为考察啤酒厂污水处理站的脱水污泥（简称啤酒污泥）用作城市污水厂接种污泥的可行性，摸索污泥的培养与驯化规律，采用连续操作、全流量同步培养和驯化方法，在处理能力为500m^2／d的UNITANK池中对啤酒污泥进行了培养和驯化。试验结果表明，啤酒污泥完全可以作为城市污水处理厂的接种污泥使用，而且培养时间短，出水水质好。曝气0．5h、厌氧搅拌1h时，活性污泥增长最快。将DO控制在2mg／L左右有利于活性污泥的增长；当DO长时间在7mg／L以上时，污泥浓度下降趋势明显。污泥浓度达到2000mg／L所需的培养驯化时间仅为5d；使出水水质达到一级B标准所需的培养时间约为6d。这种培养、驯化方法和经验可为其他城市污水处理厂的建设和运行提供参考。     

SDS和SDBS强化污泥水解的实验研究

在污泥中投加2种表面活性剂SDS和SDBS进行预处理,从COD溶出率、溶解性糖类和蛋白质3个方面对预处理后污泥的性质进行了研究。结果表明,二者的加入极大地促进了污泥的水解,低剂量范围时SCOD随投加剂量增加而显著升高,投加剂量在50 mg/g dw以上时SCOD增幅不明显。SCOD分别由初始时的638.5 mg/L最高上升到6 446.8 mg/L(SDBS)和4 857.2 mg/L(SDS),溶出率分别由初始时的5.8%最高上升到37.3%(SDBS)和30.2%(SDS)。在0~150 mg/g dw剂量范围内,溶解性糖类和蛋白质随两者投加剂量增加呈线性升高趋势,溶解性糖类分别由初始时的3.54 mg/L最高上升到95.56 mg/L(SDBS)和64.20 mg/L(SDS)。溶解性蛋白质分别由初始时的11.72 mg/L最高上升到706.30 mg/L（SDBS）和541.08 mg/L（SDS）。氨氮和VFA浓度也随投加量升高,氨氮浓度分别由初始时的4.21 mg/L最高上升到130.33 mg/L(SDBS)和102.74 mg/L(SDS);VFA浓度分别由初始时的21.27 mg/L最高上升到358.30 mg/L(SDBS)和283.12 mg/L(SDS)。     

SPME-HPLC法测定水中的酚类化合物

采用固相微萃取（SPME）高效液相色谱法（HPLC）同时测定了水中苯酚、4-硝基酚、3-甲基酚、2，4-二氯酚、2，4，6-三氯酚、五氯酚等六种酚类化合物的含量。采用ZORBOXSB—C18柱，以甲醇-1％乙酸水溶液为流动相进行梯度洗脱，流速为1．0mL／min。紫外检测波长为254、280nm。六种酚类化合物的检出限为0．31～1．90μg／L，加标回收率为88％～103％。该方法操作简单．能快竦、缝确她枪测水巾的酚娄化合物．     

Utilization of a metabolic uncoupler, 3,3',4',5-tetrachlorosalicylanilide (TCS) to reduce sludge growth in activated sludge culture

This paper studies the feasibility of using 3,3',4',5-tetrachlorosalicylanilide (TCS) as a metabolic uncoupler to reduce the sludge growth in activated sludge cultures. The results have confirmed that TCS is an effective chemical agent in limiting the sludge growth when its concentration is >0.4 mg/L. It was demonstrated that TCS was able to reduce sludge growth rate by around 40% when the TCS concentration was 0.8mg/L. It was also revealed that substrate removal capability was not affected adversely by the presence of TCS when TCS was continuously dosed in a range of 0.5-1.0 mg/L during the 30-day operation of activated sludge batch cultures. Such a sludge growth reduction is associated with the enhancement of microbial activities and an increase in the percentage of active bacteria over the total microbial population. In the 30-day operation of the cultures, the TCS dosing at a 1-mg/L level did not undermine the treatment performance in terms of the substrate removal efficiency. This work has demonstrated that it might be feasible to apply TCS in activated sludge systems to limit the excess sludge production.     

The impact of floc size on respiration inhibition by soluble toxicants--a comparative investigation

Activated sludge facilities are susceptible to upset by shock loads of toxic compounds. We hypothesized that floc size plays an important role in determining the sensitivity of mixed liquor to shock by cadmium and 2,4-dinitrophenol (DNP). To test this hypothesis, heterotrophic respiration inhibition experiments were conducted using mixed liquor from a pilot-scale membrane bioreactor (MBR) and full-scale activated sludge (FSAS) facility with gravity settling secondary clarifiers that were operated under similar process conditions. MBR mixed liquor flocs were both 41% smaller and 2 and 1.25 times more sensitive to equivalent soluble cadmium and DNP concentrations, respectively, compared to FSAS mixed liquor flocs. Similarly, FSAS mixed liquor that had been sheared (resulting in a smaller average floc diameter) was 1.5 times more sensitive to soluble cadmium than non-sheared FSAS mixed liquor. These results suggest that activated sludge process conditions that create smaller floc particles, such as the use of membranes for liquid-solid separation, are more susceptible to upset events caused by shock loads of cadmium and DNP. The particle size distribution (PSD) and average floc diameter of a mixed liquor suspension should be measured and reported when stating the inhibition concentration of a specific toxicant.     

Interactions of resin acids with aerobic and anaerobic biomass—I. Degradation by non-acclimated inocula

The fate and effects of resin acids in anaerobic and aerobic biological treatment systems were compared under batch reactor test conditions. With a non-acclimated anaerobic biomass inoculum, no degradation of resin acids was observed under anaerobic conditions after exposure times of up to 24 d. Inhibition of methanogenic activity of the anaerobic consortium was noted at initial resin acid/biomass ratios exceeding 0.0031 mg resin acids/mg VSS. Inhibited methanogenic populations were capable of acclimation to high concentrations of resin acids after 7–13 d of exposure. Under aerobic batch conditions with a non-acclimated activated sludge inoculum, high initial resin acid concentrations were reduced to detection limits in 2–3 d. The highest specific removal rate of 109 mg resin acids/g VSS · d measured in this study with non-acclimated aerobic biomass, was much higher than comparable values reported by others for acclimated aerobic biomass. The time required for removal appeared to be independent of the batch reactor biomass concentration. No evidence was found to suggest that high concentrations of resin acids resulted in inhibition under aerobic conditions.     

Nickel sorption by acclimatized activated sludge culture

The sorption of Ni(2+) by acclimatized activated sludge treating Ni(2+) bearing wastewater was investigated using a once-through completely mixed tank reactor. The culture developed from sewage was acclimatized to 85.2 microM/l Ni(2+) influent concentration by stepwise increases, at a low dilution rate 0.11/h. Acclimation was found to enhance the sorptive capacity of the activated sludge. In fact, at all of the intermediate concentrations, percentage Ni(2+) adsorbed by the biomass and also the sorptive capacity of the activated sludge drastically increased with an increase in the influent Ni(2+) concentration. All influent Ni(2+) concentrations were found to significantly stimulate the observed biomass yield of the culture over that observed in the base line. Experimental findings obtained at two other dilution rates; namely, 0.25/h and 0.45/h revealed that dilution rate is a significant operational parameter affecting the Ni(2+) sorption characteristics of acclimatized activated sludge microorganisms. Considerable complexation of nickel and organic and inorganic ligands in the wastewater appeared to be responsible for a relatively lower Ni(2+) sorption capacity.     

Nitrification in saline wastewater with high ammonia concentration in an activated sludge unit

A nitrifying activated sludge reactor fed with a high salinity medium was operated efficiently at ammonia loading rates between 1 and 4 g NH4+ -N l(-1) d(-1). The system became completely inefficient at inlet salt concentrations higher than 525 mM due to the mixed inhibition effect of salts and ammonia. The final product was mainly nitrate although dissolved oxygen limitations caused sporadic ammonia and nitrite accumulations. Specific nitrifying activity decreased due to the saline effect. A set of activity tests showed that in the continuous reactor non-adapted biomass is rather more sensitive than biomass to the saline effect. Physical properties of biomass in the reactor (sludge volumetric index and zone settling velocity) were not affected by the saline concentration, a biomass concentration of 20 gVSS l(-1) was achieved.     

The relationship of biomass to phosphate uptake by Acinetobacter junii in activated sludge mixed liquor

The involvement of Acinetobacter in biological excess phosphate removal from the activated sludge process is widely accepted, though its role is not yet clearly defined. To better understand why activated sludge systems remove phosphate, different cell concentrations of Acinetobacter junii (10⁴, 10⁵, 10⁶, 10⁷, 10⁸ cells·ml⁻¹ initial biomass) were used as inoculum in a mixed liquor medium containing sodium acetate. The phosphate uptake capacity was dependent on the biomass concentration. Low initial biomass concentrations triggered the release of phosphate once transferred into the mixed liquor. Release of phosphate increased during active growth and uptake occurred when cells reached the stationary growth phase. High initial biomass concentration of Acinetobacter junii (10⁸ cells·ml⁻¹) resulted in uptake of phosphate during the entire duration of the experiment leading eventually to complete phosphate removal.     

Effect of shock and mixed loading on the performance of SND based sequencing batch reactors (SBR) degrading nitrophenols

The effect of nitrophenolic shock loads on the performance of three lab scale SBRs was studied using a synthetic feed. Nitrophenols were biotransformed by Simultaneous heterotrophic Nitrification and aerobic Denitrification (SND) using a specially designed single sludge biomass containing Thiosphaera pantotropha. Reactors R1, R2 and R3 were fed with 200 mg/L concentration of 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) whereas reactor R was used as a background control. Three nitrophenolic shock loadings of 400, 600 and 800 mg/L d were administrated by increasing the influent nitrophenolic concentration while keeping the hydraulic retention time as 48 h. The shocks were given continuously for a period of 4 days before switching back to normal nitrophenolic loading (200 mg/L d). The reactors were allowed to recover to normal performance level before administrating the next nitrophenolic shock load. The study showed that a nitrophenolic shock load, as high as 600 mg/L d was completely degraded by the 4-NP & 2,4-DNP bioreactors while almost half degraded by the 2,4,6-TNP bioreactor without affecting the reactor’s performance irreversibly. After resuming the normal nitrophenolic loading, it took almost 8-10 days for the reactors to recover from the shock effect. The study was further extended to evaluate the maximum possible mixed nitrophenolic loading (4-NP:2,4-DNP:2,4,6-TNP 1:1:1) to which a reactor (R3) containing 2,4,6-TNP acclimated single sludge biomass can be exposed without hampering the reactor performance irreversibly. The reactor was able to achieve pseudo-steady-state at a mixed nitrophenolic loading of 300 mg/L d with more than 90% removal of all the three nitrophenols, but could remove half of the mixed nitrophenolic loading of 600 mg/L d.     

The role of the microbial stringent response in excess intracellular accumulation of phosphorous in mixed consortia fed synthetic wastewater

Four bench-scale sequencing batch reactors (SBRs) seeded with activated sludge were operated under either fully oxic or anoxic/oxic conditions and fed synthetic wastewater containing either peptone or acetate. The function of each reactor was assessed through the measure of (i) soluble chemical oxygen demand, orthophosphate, ammonia, and nitrate; and (ii) biomass concentrations of phosphorus, polyhydroxyalkanoate, guanosine tetraphosphate, adenosine monophosphate, adenosine diphosphate, and adenosine triphosphate. In all four reactors, the biomass concentration of phosphorous was correlated statistically with the biomass concentration of ppGpp. The microbial consortia in all four reactors removed an appreciable quantity of phosphorous from solution (67-99%), and the net quantity of phosphorous removed from solution corresponded to the net increase in the biomass concentration of phosphorous. Hence, the microbial stringent response (MSR) was associated with excess intracellular accumulation of phosphorous in mixed microbial consortia fed synthetic wastewater. With recognition of the potential role of the MSR in the removal of soluble phosphorous from wastewater, additional research may lead to further optimization of treatment technologies and the development of new treatment systems for the biological removal of phosphorus from wastewater.     

Phenol biodegradation and its effect on the nitrification process

Phenol biodegradation under aerobic conditions and its effect on the nitrification process were studied, first in batch assays and then in an activated sludge reactor. In batch assays, phenol was completely biodegraded at concentrations ranging from 100 to 2500 mg l(-1). Phenol was inhibitory to the nitrification process, showing more inhibition at higher initial phenol concentrations. At initial phenol concentrations above 1000 mg l(-1), the level of nitrification decreased. In the activated sludge reactor, the applied ammonium loading rate was maintained at 140 mg N-NH(4)(+)l(-1)d(-1) (350 mg N-NH(4)(+)l(-1)) during the operation time. However, the applied organic loading rate was increased stepwise from 30 to 2700 mg COD l(-1)d(-1) by increasing the phenol concentration from 35 up to 2800 mg l(-1). High phenol removal efficiencies, above 99.9%, were maintained at all the applied organic loading rates. Ammonium removal was also very high during the operation period, around 99.8%, indicating that there was no inhibition of nitrification by phenol.     

Effect of shock and mixed nitrophenolic loadings on the performance of UASB reactors

The effect of nitrophenolic shock loads on the performance of three bench-scale upflow anaerobic sludge blanket (UASB) reactors was studied using synthetic wastewater. Reactors R1, R2 and R3 were fed with 30 mg/L concentration of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4-dinitrophenol (2,4-DNP), respectively, along with methanol (COD = 2000 mg/ L), sodium nitrate (NO3(-)-N=200mg/L), and other nutrients. The reactors were in continuous operation for more than 2 years before the shock loading study was performed. Five nitrophenolic shock loadings of 45, 60, 75, 90 and 120mg/L d were administrated by increasing the influent nitrophenolic concentration to 45, 60, 75, 90 and 120mg/L, respectively, while keeping hydraulic retention time as 24h. The shocks were given continuously for a period of 4 days before switching back to normal nitrophenolic loading (30mg/Ld). The reactors were allowed to recover to normal performance level before administrating the next nitrophenolic shock load. The study showed that the nitrophenolic shock load of as high as 120 mg/L d did not affect the reactors performance irreversibly. After resuming the normal nitrophenolic loading, it took almost 3-18 days for the reactors to recover from the shock effect. The study was further extended to assess the maximum possible mixed nitrophenolic loading (2NP:4NP:2,4:DNP = 1:1:1) to which 2,4-DNP acclimated granular sludge containing reactor (R3) can be exposed without hampering the reactor (R3) performance irreversibly. The reactor was able to achieve pseudo-steady-state at a mixed nitrophenolic loading of 180 mg/L d with more than 90% removal of all the three nitrophenols, but failed at a mixed nitrophenolic loading of 225 mg/Ld.