化学品固有生物降解性试验OECD标准方法的适用性检验与改进

在经济合作与发展组织(Organization for Economic Co-operation and Development,OECD)颁布的3项固有生物降解标准测试方法中,改进的MITI(Ⅱ)(OECD 302C)方法因适用于难溶、易吸附和弱挥发等物质的固有生物降解性评估,成为目前适用范围较为广的方法。但OECD 302C对接种物规定特殊,需周期性采集不少于10个位点、不同类型的接种物进行驯养,采集、驯养和维持成本及操作复杂程度相对高,而OECD 302C方法获取的化学品生物降解率并未优于其他2项固有生物降解方法。因此,对10位点采集并驯养不同时间的接种物及污水处理厂曝气池采集的活性污泥进行微生物学特征比较,采用Biolog微生物鉴定系统及磷脂脂肪酸分析系统研究2种不同接种物的代谢活性及群落多样性,同时比较2种接种物对6种化学品的固有生物降解能力。结果表明,驯养接种物在驯养14 d后,活性与多样性开始下降,与真实环境来源接种物(10位点采集且未驯养接种物,即驯养0 d的接种物)的微生物群落差别较大。驯养1个月后的接种物在碳源利用活性、降解能力上与污水处理厂曝气池新鲜采集的活性污泥无明显差异。故笔者认为,在试验条件下,OECD 302C标准方法中的驯养接种物未达到预期目的,未经驯养的活性污泥更能反映真实环境,未来可以活性污泥作为该方法的接种物进行后续降解方法改进的研究。     

污水处理厂接种物的多样性及对化学品生物降解的影响

生物降解是化学品在环境中的主要去除途径,接种物来源和特性是快速生物降解性测试结果产生差异的重要因素。从广州和贵阳市6家生活污水处理厂采集活性污泥和二级出水,分别培养得到64和52株细菌,共有菌属为气单胞菌(Aeromonas)、芽孢杆菌(Bacillus)和肠杆菌(Enterobacter)。变性梯度凝胶电泳结果显示,广州市3家污水处理厂活性污泥和二级出水条带数量分别为53~58和38~43条;而贵阳市3家污水处理厂分别为29~42和30~42条。6种来源的接种物对易降解的萘甲酸和难降解的4-硝基苄氯生物降解测试结果较一致,接种物来源差异对中等降解性的联苯生物降解结果影响显著,其接种物多样性与生物降解性呈正相关关系。     

试验方法和接种物来源对苯甲酸钠快速生物降解率的影响

化学品的快速生物降解性直接影响其在环境中的迁移、转化和归宿,是鉴别其环境危害性和持久性的基本指标,是政府管理部门对化学品进行风险管理的重要科学依据,在生态毒理测试中具有非常重要的地位。为探讨试验方法、接种物来源以及两者的交互效应对苯甲酸钠生物降解率的影响,2013—2015年间以广州地区2个主要处理生活污水的污水处理厂(DTS、LD)为接种物来源,采用OECD 301系列试验方法(301B、301D和301F)进行了苯甲酸钠的快速生物降解性试验,共获得89个标准化测试数据。统计分析结果显示,接种物来源、试验方法与接种物来源的交互效应对苯甲酸钠生物降解率影响不显著,但试验方法单一因素的影响显著。本研究表明,当受试物为易生物降解时,接种物来源、试验方法和接种物来源的交互效应对该受试物的生物降解率无显著的影响,但在同一条件下,选择不同的试验方法往往会导致最终生物降解率出现明显差异。     

钽铌冶炼铁泥制备聚硅酸硫酸铁絮凝剂及其应用

本文以Fenton试剂法处理钽铌冶炼废水产生铁泥作为聚硅酸硫酸铁制备铁源,在不同的ω(SiO_2)、pH值、n(Fe)/n(Si)条件下优化制备了聚硅酸硫酸铁絮凝剂,并进行钨铋多金属矿选矿废水及高浊度模拟废水处理.研究结果表明:在ω(SiO_2)=1.00%、pH=3.00、n(Fe)∶n(Si)=1∶1的适宜条件下制得的聚硅酸硫酸铁絮凝剂效果最佳.在0.10%(体积分数)投加量下搅拌2 min,钨铋选矿废水浊度去除率达99.9%,COD去除率达76.8%,废水中Pb和As去除率分别达98.8%和97.2%,Be去除率几乎达100%,处理后废水浊度由319 NTU降至0.32 NTU、COD含量由322 mg·L~(-1)降至74.7 mg·L~(-1),废水中Pb和As质量浓度分别由7.89、1.03 mg·L-1降至0.09、0.03 mg·L~(-1),未检出Be;高浊度模拟废水浊度去除率达98.5%,浊度由716 NTU降至10.7 NTU.处理后废水达到《污水综合排放标准》(GB 8979—1996)一级标准.     

黑麦草在模拟人工湿地中对奶牛场污水高浓度氮的吸收转化

以土壤为基质,黑麦草(Lolium multiflorm)为植被,通过模拟间歇性人工湿地净化系统处理不同质量浓度的奶牛场污水试验,研究黑麦草对高质量浓度畜牧场污水中氮的吸收转化效果.结果表明,黑麦草在间歇性进水的污水质量浓度高达TN(816.8±125.1) mg·L~(-1),NH_4~+-N(443.6±97.9) mg·L~(-1),NO_3~--N(141.5±51.7) mg·L~(-1)都能较好的适应,生长良好.在不同浓度处理的净化系统中,水力停留时间为8d的条件下,NH_4~+-N的去除率为75.9%～88.3%;NO_3~--N的去除率平均为69.3%;TN的去除率74.5%～83.1%.该试验黑麦草对污水中氮的吸收转化在系统对氮净化中的贡献率平均为20.03%.     

试验方法和接种物来源对苯甲酸钠快速生物降解率的影响

化学品的快速生物降解性直接影响其在环境中的迁移、转化和归宿，是鉴别其环境危害性和持久性的基本指标，是政府管理部门对化学品进行风险管理的重要科学依据，在生态毒理测试中具有非常重要的地位。为探讨试验方法、接种物来源以及两者的交互效应对苯甲酸钠生物降解率的影响，2013~2015年间以广州地区2个主要处理生活污水的污水处理厂(DTS、LD)为接种物来源，采用OECD 301系列试验方法(301B、301D和301F)进行了苯甲酸钠的快速生物降解性试验，共获得89个标准化测试数据。统计分析结果显示，接种物来源、试验方法与接种物来源的交互效应对苯甲酸钠生物降解率影响不显著，但试验方法单一因素的影响显著。本研究表明，当受试物为易生物降解时，接种物来源、试验方法和接种物来源的交互效应对该受试物的生物降解率无显著的影响，但在同一条件下，选择不同的试验方法往往会导致最终生物降解率出现明显差异。     

光伏产业清洗剂废水低温生物处理

光伏产业清洗剂废水冬季生物处理难稳定达标.操作参数调控与工艺的优化组合对微生物活性的提高及清洗剂废水稳定达标处理的实现具有重要意义.本研究通过实验室摇瓶试验以COD(Chemical Oxygen Demand)去除率、COD去除速率等为表征指标探究不同温度以及低温下p H、C/N(COD/NH_4~+-N)及处理工艺等对该废水生物处理效果的影响.结果显示,10℃下清洗剂废水生物处理效果受到明显抑制,21.5 h时COD去除率仅为49.7%,较30℃下降31.0%;偏碱性条件更利于该废水的处理.p H 8条件下COD去除率较p H为5.5时提高57.2%;初始C/N在8:1到32:1之间更利于该废水的处理.清洗剂废水在生物处理后期均出现降解停滞现象.进一步比较不同工艺下清洗剂废水的低温(15℃)处理效果,在15℃、p H 7-8和C/N 16:1条件下,相比活性污泥法,接触氧化法可将COD去除率提高7.5%左右;而两段式接触氧化法可将第二段处理中的COD去除率提高16.6%左右,最终出水达到污水综合排放标准(GB 8978-1996)中的一级标准.本研究通过两段式接触氧化实现了清洗剂废水的有效处理,但是该废水的降解动力学及两段式接触氧化体系中的微生物低温降解机理还有待进一步的研究和验证.(图4表3参19)     

化学沉淀法去除稀土废水中氨氮试验

用磷酸铵镁化学沉淀法处理稀土废水中的氨氮,通过对pH值,n(P):n(N),n(Mg):n(N)及反应时间等条件进行试验,结果表明,在PH=12,n(Mg):n(N):n(P)=1.2:1:1.3,反应20min,氨氮去除率可达98%以上.氨氮初始浓度在100-200 mg·1-1左右的废水,处理后出水的残余氨氮浓度达到国家一级废水排放标准.     

乙烯基聚合物的好氧生物降解特性

在好氧活性污泥系统生物处理乙烯基聚合物,采用COD30法,并结合TOC、生化呼吸曲线、扫描电子显微镜-能谱(SEM-EDS)、傅里叶红外光谱(FT-IR)及粒径分布研究了乙烯基聚合物的好氧生物降解特性.结果表明,经过30 d的微生物作用,初始COD浓度为100、300、500 mg·L-1的乙烯基聚合物的生物降解去除率分别为37.1%、33.4%、31.1%,乙烯基聚合物的生物降解去除率随初始浓度的增大而减小.降解动力学基本符合一级速率方程,速率常数受初始浓度影响较小.TOC、生化呼吸曲线、SEM-EDS、FT-IR及粒径变化结果进一步表明,乙烯基聚合物在好氧微生物的作用下发生了一定程度的生物降解.FT-IR结果表明乙烯基聚合物的主体结构未发生显著变化,主链上碳元素被矿化的较少.     

高铁酸钾氧化降解硝基苯水溶液

采用高铁酸钾氧化降解硝基苯水溶液,研究表明,反应时间、pH值、高铁酸钾投加量、硝基苯水溶液浓度4个因素都会对硝基苯的降解效果产生影响.硝基苯水溶液浓度为55mg·l~(-1)时,初始pH=7-9,高铁酸钾投加量n_(k_2FeO_4):n_(C_6H_5NO_2)10:1,反应时间30min为最优反应条件,硝基苯去除率达到85%左右,COD_(Cr)去除率达到55%左右.通过对反应产物的分析,推测硝基苯首先被高铁酸钾氧化为对硝基苯酚,再进一步被氧化开环生成终产物.     

珠江流域野生淡水鱼中有机紫外线吸收剂的组织分布、生长稀释和物种特异性生物蓄积

以华南珠江流域9种野生淡水鱼为材料,本文研究了12种有机紫外线吸收剂（UVA）的组织分布、个体体型依赖性和物种特异性生物蓄积。鱼组织样品中12种UVA的浓度为109～2320 ng/g脂质重量（lw）。在超过一半的鱼组织样本中检测到2-羟基-4-甲氧基二苯甲酮（BP-3）、八甲基丙烯（OCR）、UV531和5种苯并三唑类紫外线稳定剂（UVP、UV329、UV234、UV328和UV327）。UV531在野生淡水鱼体内具有明显的生物蓄积潜力,其生物蓄积因子（Log BAF）和生物沉积物蓄积因子（BSAF）分别为4.54±0.55和4.88±6.78。一般来说,肝脏（989±464 ng/g lw）的UVA含量最高,其次是腹部脂肪（599±318 ng/g lw）、膀胱（494±282 ng/g lw）、背肌（470±240 ng/g lw）和卵（442±238 ng/g lw）。淡水野生鱼体内UVA的生物积累表现出物种特异性和化合物依赖性。摄食杂食性鱼类的底栖食碎屑者含有明显较高的UVA浓度,表明摄食碎屑/沉积物是野生淡水鱼暴露于UVA的重要途径。UV531和BP-3表现出生长稀释的潜力。代谢可能在消除鱼组织中的UVA方面发挥重要作用,其中肝脏的代谢率最高。在珠江流域的淡水生态系统中,UVA没有显示出明显的营养级放大作用。有必要进行更多的研究来阐明UVA在生物体内的母体转移。     

上海市典型污水处理厂污泥浸出液的化学和毒性评价

为了研究污水污泥在海洋环境中释放带来的生态风险,在分析上海7处典型污水处理厂污水污泥浸出液中重金属与溶解性有机碳的基础上,使用黑鲷,卤虫,三角褐指藻,纤细角毛藻和小球藻研究污水污泥浸出液对海洋生物的急性毒性作用和生长抑制作用。化学分析结果表明,所有样点的污水污泥浸出液中重金属总量均低于中国(GB5085.3-2007)与欧盟(EN12457.2-2002)关于危险废弃物的鉴别标准,但溶解性有机碳(DOC)含量超过欧盟标准1个数量级。毒性实验结果表明,黑鲷幼鱼对污水污泥浸出液的敏感性最强,其次是海洋微藻,卤虫无节幼体的敏感性较低;毒性综合分析结果表明,S2和S3点的污水污泥浸出液对海洋生物的综合生物毒性相对最高,而S4,S5的综合生物毒性最低,其中接纳污水为工业污水,且有机质与硫化物含量较低的污水污泥浸出液对海洋生物的综合生物毒性较低。     

Simulation der aeroben und anaeroben Abwasserreinigung mit einfachen Mitteln

Before waste-water-relevant organic materials are to be found in large quantities, their specific behavior in sewage treatment plants must be known. With the aid of the OECD simulation test #303 A, an estimation of their elimination in biological clarification stages can be made. In this work, an economical and continuous testing system is presented, which consists of a polyester flies bound to an activated biosludge with a high inoculum density, allowing one to measure no only the elimination of individual substances, but also the specific degree of mineralization. The toxicity of the activated biosludge and the nitrifying substances can also be examined. With the described testing procedure, it is possible to determine the rate of degradation within only a few hours. Finally, it can also be seen that it is possible to reliably and continuously determine the rate of anaerobic, biological degradability through the use of such a modified testing procedure.     

活性污泥系统处理苯酚废水的生物强化效果

通过性能测定观察到,菌株Candidasp.对苯酚具有较强的降解能力,因此选取来作为生物强化试验的模式菌株.通过不同接种量、不同苯酚初始浓度的比较实验,发现随着菌体加入量的增加,活性污泥系统获得的生物强化效果逐渐增强,随着初始底物浓度的增加,活性污泥系统的生物强化效果逐渐减弱,同时通过20d的长期实验发现,强化效果没有随时间减弱,而且比单独活性污泥系统经过20d驯化所得的降解能力高60%.图4参7     

7种酚类化学物质对活性污泥的呼吸抑制作用

苯酚类化学物质是废水中常见的有机污染物,其对活性污泥的毒性数据对于污水处理厂稳定运行和化学品危害性评估具有重要意义。本研究采用活性污泥呼吸抑制试验(209)测定7种酚类化学物质对活性污泥的呼吸抑制作用。结果显示,2,6-二叔丁基苯酚和对特辛基苯酚对活性污泥未产生明显的毒性效应;2,4-二氯酚、2-苯基苯酚、4-硝基酚、4-氯酚和对甲酚等5种化学物质都对活性污泥呼吸有不同程度的抑制效应,3 h-EC50值分别为49.7、77.6、102、150.1和462 mg·L-1,构效关系分析结果表明-Cl、-NO2等官能团是导致活性污泥呼吸抑制效应增强的关键因素。在化学品生物降解性测试研究中,要确保有毒化学物质的测试浓度低于EC50值的1/10。     

Biodegradability of organic substances by ATP test

The aerobic biodegradability of organic substances in water is characterized by determination of energy change ‐ ATP content in microbial cells during biodegradation. A satisfactory result is obtained under the following conditions: the initial concentration of tested substance is 100mg/l (as DOC), the amount of the inoculum in the biological medium is 500mg/l (as MLSS), and the duration of test time is 14 days. The evaluating system (peak time, peak height and IA index) is proposed to assess the biodegradability of 46 organic compounds and 7 wastewaters.     

Reassessment of the Ocean-To-Atmosphere Flux of Carbon Monoxide

Abstract

Carbon monoxide (CO) in the surface sea waters is produced predominantly by photochemical processes, oxidized by micro-organisms and outgassed to the atmosphere. to assess carbon monoxide flux from the oceans to the atmosphere, the photochemical production and microbial oxidation of carbon monoxide in the oceanic mixed-layer was investigated during several oeanographic cruises and in the laboratory. the photoproduction rate of carbon monoxide was found to be well correlated to the concentration of dissolved organic carbon (DOC) in coastal and open ocean surface waters. Taking a global average carbon monoxide production rate of 10 ± 2 nmole litre^?1 (mg DOC hr)^?1 in the surface open ocean water, and 25 ± 7 nmole litre^?1 (mg DOC hr)^?1 in coastal sea water, at cloud-free summer solar noon, the photochemical production of carbon monoxide in the global oceans is estimated to be at a rate of 1200 ± 200 Tg CO y^?1. the microbial carbon monoxide turnover time in the mixed-layer was observed to range from hours in a coastal estuary to 16 days in the Pacific along 1057deg; W in dark incubations. Natural sunlight can largely inhibit the microbial consumption of carbon monoxide in surface water. On a global scale, microbial consumption is responsible for the loss of less than 10% of photochemical produced carbon monoxide in the surface ocean. Field measurements have shown that the net transport of carbon monoxide from the euphotic zone to the underlying deeper ocean water is limited and that the overall life time in surface sea waters is less than 3-4 hours. When combined, these field measurements with the photoproduction and microbial consumption rates obtained, we estimate the oceanic flux to the atmosphere is about 1000 ± 200 Tg CO y^?1, which represents the largest single source of atmospheric carbon monoxide.     

Verhalten von Nanosilber in Kläranlagen und dessen Einfluss auf die Nitrifikationsleistung in Belebtschlamm

Background, aim and scope The application of nanosilver is increasing. Knowledge on the fate and behavior of nanosilver in wastewater and wastewater treatment plants is scarce. Studies under real world conditions are completely lacking. We studied (1) the impact of nanosilver on the nitrification of sewage sludge, (2) quantified the mass flow of nanosilver in a pilot-plant, and (3) verified the mass balance in a full-scale municipal wastewater treatment plant where nanosilver is introduced to the municipal plant by an indirect discharger. Materials and Methods The addition of four different nanosilver additives on ammonia oxidation in activated sludge has been studied in batch-reactors at two concentrations (1, 100?mg/L Ag) with two exposure times (2?h, 6?days). The pilot-plant treating 70 population equivalents of domestic wastewater is operated with a 12?day sludge age. Nanosilver was applied to the activated sludge tank within two sludge ages. The silver concentrations were measured in sludge and effluent samples during dosing and the following two sludge ages. The adsorption and speciation of silver particles has been analyzed using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Influent, effluent and sludge were sampled on a full-scale plant (60?000 equivalent inhabitants) and analyzed for silver. Results Silver nitrate, metallic nanosilver, nano-scaled silver chloride and microcomposite silver did not show any effect on ammonia oxidation after the addition of 1?mg/L Ag to the activated sludge (corresponding to 250?mg Ag per kg solids). In contrast, 100?mg/L Ag inhibited the nitrification process by 100?% after the addition of silver nitrate and 20–30?% after addition of colloidal polymer-coated nanosilver. A complete mass balance of the pilot-plant, a steady-state system with known fluxes, demonstrates significant enrichment of silver in the sewage sludge (96?%) after the addition of silver chloride to the plant and small losses of silver into the secondary effluent (4?%). The mass fluxes are similar to metallic colloidal nanosilver investigated under the same conditions. The mass balance has been consistently confirmed by the full-scale study in a municipal wastewater treatment plant. The silver fluxes correspond to the fluxes of the suspended solids in sludge and effluent. Overall, it is estimated that from public wastewater treatment plants about 4–40?mg/a Ag per inhabitant equivalent are discharged annually to the receiving water. The analysis by SEM-EDX demonstrates adsorption and incorporation of nanosilver on biological flocs. This method yields first insight into complex building and transformation of silver associated with sulfide after adding metallic nanosilver and silver chloride to wastewater. Discussion Silver ions released from nanosilver react immediately with large amounts of chloride present in wastewater to form silver chloride. Silver ions may react with organic ligands or sulfide groups additionally. Consequently, even silver nitrate added with 1?mg/L Ag (250?mg Ag/kg TS) to activated sludge did not inhibit nitrification activity. Very high amounts of nanosilver, i.?e. 100?mg/L Ag, overburdened the system and equilibrium condition between silver ion release and ligands was not reached. The mass balance reflects the excellent attachment of nanosilver to activated sludge and biological flocs. Therefore, the main elimination process of nanosilver is attachment to the activated sludge. The elimination of nanosilver is high compared to organic and inorganic micro pollutants omnipresent in wastewater. Any further reduction of suspended solids in the effluent water will reduce the silver load. Conclusions Generally, in wastewater nanosilver occurs bonded to activated sludge flocs and therefore the elimination of nanosilver is efficient under operation conditions typical for wastewater treatment plants. The major fraction of nanosilver is removed from the system by the excess sludge withdrawal. Nonetheless, the efficiency may be further improved by a tertiary filtration step. All analyses of influent, effluent and sludge confirmed that silver exists as silver sulfide. Due to a negligible water solubility of this silver species, silver ions are not subsequently released. Recommendations and perspectives Nanosilver research should be driven to the identification of transformation processes in real environmental matrices and the influence of coatings on the adsorption behavior. There is no need for action to take special measures for nanosilver removal in the area of municipal wastewater treatment plants compared to ubiquitous hazardous organic pollutants may present in wastewater. Nevertheless, source control measures following the precautionary principle should be performed.     

花生壳活性炭对反渗透(RO)浓水的吸附特性

以花生壳活性炭对RO浓水进行吸附处理,利用傅立叶红外光谱(FTIR)和荧光光谱(EEM)研究花生壳活性炭对不同pH的RO浓水的吸附特性.结果表明,花生壳活性炭对溶解性有机碳(DOC)的吸附遵循准二级吸附动力学方程,特别是碱性条件下,DOC的吸附量随着pH的升高而降低.而且pH越高,达到吸附平衡的时间越长.通过FTIR光谱分析发现,活性炭的芳香结构吸收峰在吸附后红移至1630 cm-1,表明被吸附的有机物在该处有明显的特征吸收峰,而C—O和O—H官能团的吸收峰则因为钙离子等物质的吸附而显著降低.由EEM光谱分析可知,RO浓水的荧光物质主要由腐殖酸类腐殖质和富里酸类腐殖质组成,其荧光强度与DOC之间具有较好的线性相关性.     

Acid mine-drainage toxicity testing

The BOD inhibition test, the activated sludge respiration inhibition test, and the Microtox® Bioassay procedure were examined for their potential as rapid toxicity screening methods for acid mine drainage (AMD) and for setting toxicity threshold levels in receiving waters. The BOD inhibition test proved to be unsuitable due to the high chemical oxygen demand of the toxicant. The long incubation time (minimum 5 d at 20°C) allowed growth of chemo-autotrophic bacteria and resulted in excessive flocculation and precipitation of metals, making accurate and meaningful measurements of inhibition impossible. The activated sludge respiration inhibition test was successful in measuring AMD toxicity, and for deriving toxicity threshold levels for the basic heterotrophic community in surface waters. However, it is a very time-consuming technique and is not sensitive enough to be used as a routine screening technique. The variability in toxicity was found to be due to the availability of metals as well as the effect of pH on metabolism. Simple linear models were derived to estimate inhibition within surface waters. Prediction of the inhibition caused by AMD can be made as long as the pH of the river water after mixing and the dilution of the AMD are known. Most accurate predictions are made using equations for specific pH ranges, but a useful estimation of inhibition can be obtained using the general equation: inhibition (%) = -2.34 pH + 6.41 AMD (%) + 22.1. The Microtox® Bioassay method, although expensive, was rapid and simple to use. It was the most sensitive test of the three, with the toxic response of marine bacteria increasing notably from 5 to 15 min due to the presence of bivalent metals in the toxicant. The problem of repeatability and reproducibility encountered with the activated sludge inhibition test was overcome with the highly standardised Microtox® method, making it an ideal screening method for AMD. However, the advantage of the activated sludge inhibition test is that the types of heterotrophic micro-organisms found in activated sludge are similar to those found in receiving waters such as the Avoca River and so more meaningful toxicity threshold values can be obtained.