Treatment of tannery wastewater by chemical coagulation

The objective of this study was to develop a treatment system that can effectively reduce the concentration of pollutants in tannery wastewater to environmentally acceptable levels and that can greatly reduce the cost of discharging the effluents. Aluminium sulphate and ferric chloride were used as a coagulant in the process. The influence of pH and coagulant dosages on the coagulation process was studied and conditions were optimised corresponding to the best removal of organic matters, suspended solids as well as chromium. The COD and chromium were removed mainly through coagulation: 38-46% removal of suspended solids, 30-37% removal of total COD from settled tannery wastewaters and 74-99% removal of chromium at an initial concentration of 12 mg/l can be achieved by using the optimum coagulant dosage (800 mg/l) in the optimum pH range (around 7.5). Ferric chloride produced better results than aluminium sulphate. The initial chromium concentrations and pH values of the wastewater had a great effect on chromium removal efficiency. Low chromium concentrations and high pH produced a more effective result on chromium removal than high chromium concentrations and low pH. Higher dosages did not significantly increase pollutant removal and were not economical. Coagulation combined with centrifugation improved the removal efficiency of suspended solids (70%). A high degree of clarification is attained as indicated by an excess of 85-86% colour removal. The results provide useful information for tannery wastewater treatment.     

硅藻土颗粒在处理煤气废水活性污泥系统中的作用

Diatomite is a kind of natural low-cost mineral material. It has a number of unique physical properties and has been widely used as an adsorbent in wastewater treatment. This study was conducted to investigate the aerobic biodegradation of coal gasification wastewater with and without diatomite addition. Experimental results indicated that diatomite added in the activated sludge system could promote the biomass and also enhance the performance of the sludge settling. The average mixed-liquor volatile suspended solids (MLVSS) is increased from 4055 mg•L－1 to 4518 mg•L－1 and the average settling volume (SV) are changed only from 45.9% to 47.1%. Diatomite additive could enhance the efficiency of chemical oxygen demand (COD) and total phenols removal from the wastewater. The COD removal increased from 73.3% to near 80% and the total phenols removal increased from 81.4% to 85.8%. The mechanisms of the increase of biomass and pollutants removal may correlates to the improvement of bioavailability and sludge settlement characteristics by diatomite added. Micrograph of the sludge in the diatomite-activated sludge system indicated that the diatomite added could be the carrier of the microbe and also affect the biomass and pollutant removal.     

高浓度制药废水毒性与SPAC反应器运行性能

采用发光细菌法测试了高浓度硫酸盐制药废水中典型污染物（硫酸盐）、转化产物（硫化物）、供试制药废水原水、稀释6倍厌氧处理出水和稀释3倍厌氧处理出水的毒性,硫酸盐、硫化物的半抑制浓度分别为12077.8、78.1 mg·L^-1;供试制药废水原水、稀释6倍厌氧生物处理出水和稀释3倍厌氧生物处理出水的半抑制浓度分别为64.5、44.7和78.9倍。试验了SPAC厌氧反应器处理高浓度硫酸盐制药废水的运行性能,高浓度低流量运行时,反应器最大容积COD、硫酸盐（以SO₄^2-计,下同）去除速率分别为5.76、1.83 kg·m^-3·d^-1,COD和硫酸盐去除率分别为54.1%和71.8%;低浓度高流量运行时,反应器的最大容积COD、硫酸盐去除速率分别为7.52、1.90 kg·m^-3·d^-1,COD和硫酸盐去除率分别为72.8%和80.0%。低浓度高流量运行更易使反应器取得高效。试验了SPAC厌氧反应器对高浓度硫酸盐制药废水毒性抑制的适应性能,运试初期宜将废水稀释5.13倍以上,运试后期可将原水稀释3.32倍。     

Simultaneous treatment of semiconductor wastewater and distillery slops by mixing and precipitation/coagulation

Organic matter (chemical oxygen demand, COD) removal with decolorization in waste distillery slops and copper removal in a semiconductor industry wastewater were achieved in a single step mixing and precipitation/coagulation treatment system. The process utilized the complementary properties of the positively charged copper ions in semiconductor wastewater and net negative charge of melanoidin (organic chromophoric pollutant) in distillery slops to mutually neutralize each other. Copper ions served as coagulant for slops and melanoidin served as precipitant for copper. The volumetric ratio of the wastewater and pH were optimized to attain maximum removal of organic matter and copper. The optimum volumetric ratio for the evaluated semiconductor wastewater to distillery slops was found to be 2–3 with an equilibrium pH of around pH 6. At optimum conditions, average removals of COD and copper were 86% and 92%, respectively, in an actual and undiluted system. Decolorization efficiency using the diluted distillery slops was 89%. The process can be considered an effective pretreatment procedure for simultaneous gross removal of copper and color/COD, particularly in highly concentrated waste streams. Copyright © 2005 Society of Chemical Industry     

Comparison of different fluid dynamics in activated sludge system for the treatment of a stimulated milk processing wastewater: Process analysis and optimization

Wastewater from the milk industry usually undergoes activated sludge ahead of refining treatments, final discharge or reuse. To identify the most effective bioreactor hydraulic regime for the secondary treatment of wastewater resulting from the milk industry in an activated sludge system, two lab-scale activated sludge systems characterized by a different configuration and fluid dynamics (i.e., a compartmentalized activated sludge (CAS) with plug flow regime and a complete mixed activated sludge (AS)) were operated in parallel, inoculated with the same microbial consortium and fed with identical streams of a stimulated dairy wastewater. The effect of three process and operational variables??influent chemical oxygen demand (COD) concentration, sludge recycle ratio (R) and hydraulic retention time (HRT)??on the performance of the two systems were investigated. Experiments were conducted based on a central composite face-centered design (CCFD) and analyzed using response surface methodology (RSM). The region of exploration for treatment of the synthetic wastewater was taken as the area enclosed by the COD _in (200, 1,000 mg/l), R (1, 5), and HRT (2, 5 h) boundaries. To evaluate the process, three parameters, COD removal efficiency (E), specific substrate utilization rate (U), and sludge volume index (SVI), were measured and calculated over the course of the experiments as the process responses. The change of the flow regime from complete-mix to plug flow resulted in considerable improvements in the COD removal efficiency of milk wastewater and sludge settling properties. SVI levels for CAS system (30?C58 ml/g) were considerably smaller that for the AS system (50?C145 ml/g). In addition, the biomass production yield could be reduced by about 10% compared to the AS system. The results indicated that for the wastewater, the design HRT of a CAS reactor could be shortened to 2?C4 h.     

木质填料床A/O系统处理低C/N比养猪废水的效能与脱氮机制

针对干清粪式养猪废水 浓度高和低C/N比的特点构建了四格室木质填料床A/O处理系统,通过调控运行探讨其除氮效能和机制。结果表明,在HRT 18.7 h、32℃、硝化液回流比200%、好氧区DO 1.5 mg·L^-1等条件下,即便进水 高达307.7 mg·L^-1,COD/TN平均为0.47,系统对COD、 和TN的去除率仍能维持在66.5%、93.6%和89.0%左右,TN去除负荷达到0.22 kg·m^-3·d^-1以上。系统对COD和TN的去除表现出一定的空间分区特征,其中前三厌氧格室是去除COD主要功能区,末端好氧格室是脱氮功能区。系统的脱氮机制以短程硝化反硝化为主,枯木填料的腐解为反硝化提供了必要的碳源。     

Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

A pilot scale modified step-feed process was improved to increase nutrient(N and P)and organic removal operations from municipal wastewater.It combined the step-feed process and a method named "University of Cape Town(UCT)".The effect of nutrient ratios and inflow distribution ratios were studied.The highest uptake efficiency of 95% for chemical oxygen demand(COD)has been achieved at the inflow distribution ratio of 40/35/25.However,maximum removal efficiency obtained for total nitrogen(TN)and phosphorus at 93% and 78%,respectively.The average mixed liquor suspended solids(MLSS)was 5500 mg·L~(-1).In addition,convenient values for dissolved oxygen(DO)concentration,and p H were obtained throughout different stages.The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal,sturdy sludge settle ability and COD removal.     

电解阳极间接氧化法处理制药废水的研究

通过在废水中加入NaCl电解质，考察了电解阳极间接氧化法制药废水的处理效果。实验分析了废水中电解质NaCl对制药废水电解过程中CODCr、色度去除的影响，并对不同用量NaCl电解效果进行了对比。另外还用电解质Na2SO4、NaNO3作了对比实验来说明NaCl产生的电解阳极间接氧化的存在。最后对甲红霉素废水进行中试实验，结果表明，NaCl电解产生的NaClO具有极强的氧化性，促进了CODCr的去除，同时还发现，废水中氨氮的存在不利于废水CODCr的去除。     

厌氧/特异性移动床生物膜反应器处理焦化废水

采用厌氧/特异性移动床生物膜反应器(AMBBR/SMBBR)工艺对焦化废水进行生物降解,在单因素实验基础上,通过基于Box-Behnken设计的响应面法对SMBBR实验参数进行优化,并采用气相色谱-质谱(GC/MS)检测各单元废水中有机组分变化,探究有机污染物降解机理.结果表明,工艺运行参数在DO的质量浓度为5 mg/...     

Combined performance of electrocoagulation and magnetic separation processes for treatment of dye wastewater

In this study, a combined system of electrocoagulation (EC) and magnetic separation (MS) has been applied to the treatment of dye wastewater, and its performance has been evaluated. The floes formed in the electrocoagulation using Fe anode are magnetized and thus they could be removed by magnetic separation. The removal of suspended solids, color and COD was improved with an increase in electric current up to about 15 A and with a decrease in liquid velocities in EC. While the remaining suspended solids in the treated water were reduced to a few ppm and the color was removed almost perfectly (Max. 96%), that of COD was relatively low and only 81%. A further powerful operation can be expected from the present system if it is combined with an additional process, such as electrolysis or oxidation, to reduce COD more efficiently.     

杂环类制药废水处理工艺探讨

通过对某制药厂杂环类制药废水处理工艺的考察，确定了处理废水的最佳方案。首先对该废水进行冷却结晶，盐分析出率最高达70％左右；然后用Fenton试剂对其进行氧化处理，可使TOC去除率达到50％以上，可生化性达0．6左右；最后用活性污泥法对该废水进行生化处理，可使出水指标达国家排放标准。     

樊立萍1,*,温越霄1,2

为提高微生物燃料电池(MFC)的废水处理效果和发电性能,制备了一种海藻酸钠-聚季铵盐11/碳毡(SA-PQ-11/CF)阳极,分别以制药废水和糖蜜废水为阳极液,以碳毡为阴极,构建微生物燃料电池(MFC)实验系统,通过扫描电子显微镜(SEM)、电化学阻抗谱(EIS)、循环伏安特性(CV)、化学需氧量(COD)对其性能进行表征。结果显示,SA-PQ-11/CF阳极具有较大的比表面积,MFC的溶液电阻和电荷转移电阻也得到明显降低。阳极液为制药废水时,采用SA-PQ-11/CF阳极的MFC的稳态输出电压和COD去除率分别约为0.22 V和62%,较常规碳毡阳极时分别提高了100%和130%。阳极液为糖蜜废水时,采用SA-PQ-11/CF阳极的MFC的稳态输出电压和COD去除率分别为0.15 V和43%,分别较采用常规碳毡阳极时提高了275%和95%。基于SA-PQ-11的阳极改性能够有效提高MFC的废水处理效果和产电能力。     

Fenton试剂对染料废水的降解脱色作用研究

为了进一步探讨Fenton法对某些难降解有机物的降解效果,研究影响降解的诸多因素,以甲基橙模拟染料废水为研究对象,以色度和COD去除率为检测指标,研究了Fenton反应中pH值、H2O2浓度、Fe2+离子浓度、反应时间、温度对甲基橙模拟染料废水脱色率及COD去除率的影响规律.结果表明:Fenten试剂可有效地去除甲基橙模拟染料废水中的色度和COD.染料浓度为200mg/L时,在pH=4、20℃、H2O2=(浓度为30%)投量为0.6mL/L、硫酸亚铁投量为200mg/L时,反应60min,甲基橙模拟染料废水的色度去除率可以达到99.66%,COD的去除率可达88%.     

上流式厌氧污泥床反应器处理凉果废水性能研究

采用上流式厌氧污泥床反应器(UASB)法处理凉果废水,考察废水厌氧处理过程中COD、浊度、脱色率、pH、电导率、悬浮物去除率的变化规律。结果表明:随着厌氧时间的增加,UASB反应器对废水的处理效果不断提高。在最适宜的厌氧时间条件下,废水的COD去除率达62.0%、浊度去除率达41.1%、吸光度及脱色率分别为0.498及48.4%、pH为5.4、悬浮物去除率达30.3%。故,UASB法可作为凉果废水的预处理方式,以降低后续废水的好氧处理难度。     

微波和超声波处理制药废水初探

研究了相同功率(400 W)条件下超声波、微波分别处理制药废水的效果,结果表明:(1)在处理的初始超声波、微波均使COD有先升高后下降,最后趋于稳定的现象;就去除COD而言,在运行条件为400 W时,处理制药废水的最佳时间为240 s.(2)超声波、微波处理制药废水NH3-N去除率都能达到47%,开始NH3-N下降较快但随后有波动,在480 s后NH3-N分别稳定在14、6 mg/L.此外,在功率400 W,处理时间240 s条件下,微波和超声波分别与生物接触氧化法组合处理制药废水对COD和NH3-N去除率＞60%.使用总体综合特征的假设性检验(a=0.05),两种组合处理制药废水对COD和NH3-N的去除效果不存在显著差异.     

水解酸化-好氧MBBR耦合Fenton法处理抗生素废水研究

采用水解酸化—好氧移动床生物膜(MBBR)串联Fenton工艺处理抗生素废水,探讨了pH、HRT等对水解酸化以及Fe2 浓度和H2O2投加量对Fenton工艺的影响。实验结果表明,对于COD为6800.62mg/L、B/C<0.3的抗生素废水,当水解段pH和HRT分别为6.5和12h时,挥发酸(VFA)质量浓度为931.75mg/L,COD去除率为26.59%,此时水解酸化—好氧段出水COD为1229.80mg/L,COD总去除率为81.92%。再经Fenton工艺深度处理,当Fe2 最佳投加质量浓度为240mg/L,H2O2投加量为3.19mL/L时,总COD去除率可达97.38%,最终出水COD为178.50mg/L,达到制药工业废水排放标准。     

生物反应器去除COD、氨氮和油的中试研究

研究了一体式固定化生物活性炭(IBAC)反应器在炼油废水深度处理中的除污染效能,采用常规方法通过多次由富营养到贫营养的驯化,筛选出除COD、氨氮和油的工程菌,通过连续循环固化后进行试验研究。试验结果表明:当水力停留时间为40min时,反应器对COD、氨氮和油去除率均>90%,出水满足循环冷却水的用水要求,为炼油工业废水深度处理开辟了一条简捷的新途径。     

碱化／蒸发／汽提组合工艺处理制药废水的研究

针对制药废水高COD、高NH3-N和有机物难降解的特点,提出了碱化、蒸发和汽提工艺组合的处理方法,考察了NaOH加量、蒸发量及汽提量对废水COD及NH3-N去除效果的影响。结果表明,组合工艺对废水的COD、NH3-N有很高的去除率。在NaOH加量为20g·L-1、蒸发量为80％、汽提量为1．0％的条件下,COD去除率最高达99．4％、NH3-N去除率最高达98．5％;同时,提高了出水的可生化性,出水COD和NHa—N均达到了《制药工业水污染物排放标准》（GB21907—2008）。     

高盐难生化制药废水工程实例

蒸馏-UASB-深层曝气．兼氧-A／O接触氧化处理制药废水，BOD5和COD的去除率分别达到995％和99．8％，出水达到《山东省小清河流域水污染物综合排放标准》（DB37／656-2006表2）一般保护区域最高允许排放浓度要求。工程对含盐废水、难生化废水、综合废水进行分步治理，经过一年多的运行表明，该工艺运行稳定，处理效果好，为此类废水提供参考。     

Experimental study on electrocoagulation of textile wastewater by continuous horizontal flow through aluminum baffles

We investigated the feasibility of applying a continuous textile wastewater (TWW) treatment, which was accomplished by using electrocoagulation (EC) unit with zigzag horizontal flow across a series of mono-polar aluminum plate baffles. The effects of operating parameters such as current density (20-80 A/m²) and detention time (5-40 min) on turbidity, color, chemical oxygen demand (COD), total suspended solids (TSS) and total dissolved solids (TDS) removal were studied. The optimum conditions were determined as 60 A/m² and 20min by monitoring zeta potential (ζ) of effluent. At the optimum conditions, removal efficiencies for turbidity (97.63%), color (87.87%), COD (93.3%), TSS (94.02%), and TDS (52.13%) were observed. Further, addition of 4mg/L of NaCl dose in the TWW modified conductivity suitably, thereby reducing electrical energy consumption per cubic meter of waste water and specific electrical energy consumption (SEEC) from 13.33 to 2.67kWh/m³, and 23.84 to 4.77kWh/kg Al, respectively. Comparing the EC with conventional coagulation process, EC showed better pollutant removal efficiency.