好氧活性污泥处理含氰废水的试验研究

基于含氰废水在不同条件下的好氧活性污泥降解试验,针对好氧微生物降解CN-的适宜条件进行了试验研究。试验结果表明,当pH值、温度、葡萄糖投加量、牛肉膏投加量、好氧活性污泥投加量等试验条件发生变化时,活性污泥中好氧微生物对氰化物的降解效果也相应产生变化。同时,也考察了环境改变对好氧微生物降解氰化物的影响,提高了氰化物的降解效果。     

活性污泥法处理工业酚氰废水的若干问题

兖州矿区焦化厂采用活性污泥法处理工业酚氰废水，通过培养和驯化活性污泥微生物，制订了严格的工艺指标和参数，使处理后的工业污水达到国家排放标准。     

微生物处理含氰废水的试验研究

文中以辽宁天利金业有限责任公司生物氧化提金厂经酸化处理后的含氰废水为原液进行了生物降氰条件试验。试验结果表明,菌种在pH 7、温度28℃、摇床转速110 r/min、接种量50%、葡萄糖量1 g/L、牛肉膏量1 g/L时,可以达到最佳的降氰效果;经62 h处理后,总氰可由100 mg/L降解到0.5 mg/L以下。     

生物法处理金矿含氰废水同步收金技术研究与应用

开展生物法处理金矿含氰废水同步收金技术研究,通过改良缺氧-好氧生物处理工艺,成功驯化增殖了以硫杆菌、特吕珀菌、假单胞菌为主的CN^-、SCN^-高效降解菌群。在工业应用上,生物法对SCN^-、COD、CN^-、NH₃-N的平均去除率分别为99.99%、97.54%、93.92%和98.92%,处理后的出水各项污染物指标远低于《污水综合排放标准》(GB 8978—1996)一级标准。微生物在降解废水污染物的同时,通过自身的氧化、吸附、絮凝沉降等作用,对起始浓度低的混合含金废水进行金回收,金的回收率可达到91%,富集金品位300～400 g/t,不仅深度处理了废水中各项污染物,同时回收了有价金属,是一种环境友好且无公害的含氰废水处理技术。     

含氰废水的综合处理

本文分析了含氰废水的来源及其危害,回顾了近年来含氰废水治理技术,介绍含氰废水各种处理方法的特点,同时指出了这些方法的应用范围及局限性.对如何选择合氰废水的处理方法提出了一些看法.     

含氰废水光化学降解的试验研究

对含氰废水进行了不同自然光照条件下的降解模拟试验研究。试验结果表明,光照越强,氰化物降解越快;温度、pH值、搅拌速度对自然光降解氰化物影响较大,温度越高pH值越小、搅拌速度越高．氰化物降解越快,去除率越高。同时,还对比试验了紫外光照条件下的氰化物降解,结果表明,紫外光对氰化物的降解速度远高于自然光。用溶胶凝胶法制备的TiO2为微细粉末状晶体,在光氧化舍氰废水中催化效果较好。在最佳试验条件下,降解质量浓度为14．81mg／L的含氰废水需150min即可达到排放标准。对降解反应的动力学进行了分析,结果表明,光化学降解氰化物为一级反应。     

试论国内黄金矿山含氰废水的处理

本文论述了我国黄金矿山含氰废水处理的几种主要方法，就其优缺点和适应性进行了评价。并对有关方法进行了展望。     

Chemical Oxygen Demand and the Mechanism of Excess Sludge Reduction in an Oxic-Settling-Anaerobic Activated Sludge Process

A modified activated sludge process, called the oxic-settling-anaerobic (OSA) process, achieved effective reduction in excess sludge production. Its key feature is the insertion of a sludge holding tank in the sludge return circuit to provide an anaerobic sludge zone. Our previous studies suggested that such excess sludge reduction might be associated with an increased sludge decay rate and the effective consumption of organic substrates generated during the retention of the thickened sludge in the sludge holding tank under a low oxidation-reduction potential (ORP) at ?250?mV. To confirm this suggestion, we analyzed the chemical oxygen demand (COD) balance in the sludge holding tank through batch experiments to simulate the sludge concentration, ORP level, and retention time in the sludge holding tank. The COD generated from the sludge reduction in the tank was utilized by organic gas (mainly CH4) production, denitrification, sulfate reduction, and phosphorus release, among which the gas production accounted for 50% of the COD utilization. We confirmed that the mechanism of the excess sludge reduction in the OSA process is through enhancement of the sludge decay rate in the anaerobic sludge zone, which increases the soluble COD level, which in turn is mainly transformed into methane gas and carbon dioxide during denitrification.     

Simulating Activated Sludge System by Simple-to-Advanced Models

Models ranging through simple, intermediate, and International Water Association complex activated sludge models (ASMs) were evaluated to compare their ability to describe biomass growth and substrate removal in an activated sludge system. A membrane-activated sludge bench-scale system was used to treat a complex synthetic wastewater over a wide range of operating conditions, ranging from 1 to 15 days solids retention time and 4 to 12 h hydraulic retention time. Total suspended solids, volatile suspended solids (VSSs), and total and soluble chemical oxygen demands (CODs) were monitored in the influent, the reactor, and the effluent. A variety of substrate removal formulations were used with the simple and intermediate models. Although all models provide excellent prediction of biomass growth, the intermediate model was best. Prediction of substrate removal was good with models that incorporated a nonbiodegradable component in the influent. ASM3 was the best model for predicting effluent soluble COD, but overall, the intermediate model was judged best for prediction of mixed liquor VSS and effluent soluble COD.     

市政污泥及其热处理渣对CHO-K1细胞的毒性研究

评估市政污泥资源化产物的健康风险对其安全规范利用具有指导意义。分别对某污水处理厂的污泥进行了热解和好氧发酵处理,运用中国仓鼠卵巢细胞（CHO-K1）对市政污泥及其热处理渣开展细胞毒性试验和遗传毒性试验,评估其对典型哺乳动物细胞的危害和潜在风险。结果显示,与原污泥样品相比,污泥热解渣和好氧发酵渣的细胞毒性和遗传毒性均降低。与原污泥样品相比,RTCA细胞增殖试验结果显示,污泥热解渣和好氧发酵渣对CHO-K1细胞的生长抑制性明显减弱;CCK-8细胞毒性试验结果显示,污泥热解渣和好氧发酵渣的细胞相对存活率分别增加了161%和137%;Caspase 3细胞凋亡蛋白酶活力试验结果显示,暴露于污泥热解渣和好氧发酵渣中的CHO-K1细胞的Caspase 3凋亡蛋白酶的活性分别降低了29.3%和20.1%;彗星试验结果显示,污泥热解渣和好氧发酵渣的尾长分别缩短了64.5%和25.9%,尾矩分别减少了78.4%和28.1%。研究结果表明,热处理技术（热解处理和好氧发酵处理）可减少市政污泥的细胞毒性和遗传毒性,降低市政污泥对生态环境和人体健康的潜在风险。     

Adsorption of Perfluorinated Compounds onto Activated Carbon and Activated Sludge

The adsorption of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) onto powdered activated carbon (PAC) was investigated in the presence and absence of effluent organic matter (EfOM) at an environmentally relevant concentration range (0.1–500??μg/L). Adsorption of PFOS and PFOA to PAC fitted the Freundlich model well (r2>0.98), and adsorption capacity of PFOS (KF = 17.48) and PFOA (KF = 10.03) in the absence of EfOM was more than one order of magnitude higher than that in the presence of EfOM (KF = 0.66 for PFOS, KF = 0.20 for PFOA), indicating that EfOM greatly reduces the adsorption capacity of PAC. Moreover, EfOM was characterized by ultrafiltration, and fractions of nominal molecular weights were obtained to investigate their effect on the PFOS and PFOA adsorption. The fraction of <1??kDa had greater effect on adsorption than the fraction of >30??kDa, indicating that the similar molecular size of target compounds was the major contributor to adsorption competition. Additionally, biosorption of PFOS and PFOA to activated sludge fitted the linear isotherm (r2>0.9) within a concentration range of 50–400??μg/L. On the basis of our data, the estimated partition coefficient, Kd, was 729??L/kg for PFOS and 154??L/kg for PFOA, respectively, suggesting that PFOS and especially PFOA have a low tendency to partition onto sludge.     

Statistical Comparison of Bioassays for Assessment of Toxicity of Organic Components of Wastewater to Activated Sludge

In aquatic toxicity testing, no single test species responds appropriately to all toxicants. Therefore test batteries consisting of several individual assays are becoming more common. The species comprising a test battery should be representative of the entire system of interest. Each assay should be complementary to other components in the test battery and the test battery should not include redundant tests. We studied the selection of test battery components for the assessment of the toxicity of organic chemicals to activated sludge. The assays considered were the continuous Shk1, Microtox, Polytox, activated sludge respiration inhibition, Nitrosomonas, and Tetrahymena assays. The correlations between the toxicity data obtained from these assays were analyzed by examining the correlation matrix and by principal component analysis. These statistical methods showed that the Nitrosomonas assay should be included in test batteries plus one of the remaining five assays for assessing toxicity of organic compounds to activated sludge.     

氰化尾渣制备铁碳微电解填料降解苯甲羟肟酸废水

氰化尾渣是黄金氰化提金过程中产生的主要危险固体废弃物。以氰化尾渣为原料,利用其较高的铁品位,通过还原焙烧制备铁碳微电解填料,通过探究填料制备条件和降解条件对苯甲羟肟酸废水降解效果的影响,考察该填料用于处理苯甲羟肟酸废水的可行性。结果表明,最佳焙烧条件为：焙烧温度1 200℃、无烟煤用量20%、焙烧时间10 min;最佳降解条件为：铁碳微电解填料用量3.75 g/L、溶液pH=4,该条件下,废水中的苯甲羟肟酸去除率可达80%以上。该方法不仅实现了氰化尾渣的资源化利用,而且可以有效降解苯甲羟肟酸废水,实现了“以废治废”的目的。     

低钛烧结矿还原粉化机理研究

国内某厂生产的低钛烧结矿可用于2 500 m3高炉冶炼,强度指标达到普通烧结矿水平,但其低温还原粉化率仍比普通烧结矿高40%以上,还原粉化机理尚不明确。通过分段测试低钛烧结矿的还原粉化率并进行矿相分析,结果发现:低钛烧结矿中的赤铁矿-气孔结构是产生裂纹的源头,铁酸钙熔蚀结构是主要粘结相,但此结构中有许多细小裂纹,裂纹沿程存在许多赤铁矿晶粒,其还原速率较快且易形成交叉网状裂纹,使粘结相结构受到严重破坏,致使烧结矿还原粉化性能差。     

Density and Activity Characterization of Activated Sludge Flocs

Activated sludge flocs are made up of a conglomerate of materials including microorganisms, exocellular polymers, inert particulates, slow and nonbiodegradable organic particles, and water. The goal of this study was to determine if inert/unbiodegradable aggregates had higher densities than active biomass. It was also desired to determine whether mixed liquor could be gravimetrically settled to differentially stratify flocs based on density and biological activity. In this manner, if activity stratification is possible, then less active biomass could be wasted preferentially during wastewater treatment operations (e.g., during daily wastage), thereby increasing the effective solids retention time and improving process performance. This paper reports the initial set of results, which focused on establishing density values of inert/unbiodegradable fractions of activated sludge floc, and the heterotrophic activity measurements of faster settling flocs compared to slower settling flocs. The results indicate that activated sludge from a local wastewater treatment plant had aggregate densities as low as 1.038?g/mL for slower settling floc particles and as high as 1.065?g/mL for faster settling floc particles. Primary effluent “inert+unbiodegradable particulate organic” fractions, which ultimately accumulate in mixed liquor and contribute to the inactive activated sludge floc fraction, had densities of approximately 1.24?g/mL. Mixed liquor that was digested in excess of 90 days to reduce any degradable organics revealed aggregate densities between 1.11 and 1.12?g/mL. Settling column experiments indicated that floc particles settled at rates ranging from less than 5?m/h to greater than 30?m/h. Specific oxygen uptake rates signified that the heterotrophic activity was homogeneous across all settling velocities except those flocs with a settling velocity of less than 5?m/h. These flocs exhibited a specific oxygen uptake rate of between 31 and 110% higher than the remaining floc. Determination of the mass fraction of these flocs indicates that they account for approximately 2% of the overall biomass. This low fraction limits the usefulness of differentially settling unaltered waste activated sludge to recover portions with higher activity.     

电镀污泥的固化及浸出毒性研究

采用水泥和细砂作固化基材处理含Ni、Cr、Cu等重金属的电镀污泥，对固化块的浸出试验表明：水泥固化该电镀污泥效果良好，固化过程中加入适当的螯合剂KS-3，可以提高固化效果，并对固化块在不同pH浸取剂下的重金属浸出浓度进行了研究。     

Activated Sludge Process Modification for Sludge Yield Reduction Using Pulp and Paper Wastewater

Implications of conventional activated sludge (CAS) process modification to a low sludge production (LSP) process have been studied for treating pulp and paper wastewaters. The activated sludge process is modified to a two-stage design to establish a microbial food chain that would result in reduced sludge production. The return activated sludge in the LSP process bypasses the first (dispersed growth) stage to be received only by the second (predatory) stage. The resulting once-through operation of the dispersed growth (DG) stage makes it potentially susceptible to bacterial washout under hydraulic shock conditions. A sensitivity analysis of the DG stage operation was performed by varying its hydraulic residence time. The experimental data revealed that the optimal DG stage hydraulic residence is between 3 and 5?h, with bacterial washout likely to be initiated within 2?h. Based on laboratory results, it appears that a well-designed LSP system is likely to be able to handle day-to-day variations in hydraulic and organic loading rates. The LSP process produced 36% less sludge than the CAS process while consuming approximately 25% more oxygen. The treatment performance of the two systems was comparable except that the LSP sludge had much better settling and dewatering properties.