广玉兰、龙爪槐和黄杨化感物质对铜绿微囊藻生长的抑制

针对水华的主要物种——铜绿微囊藻,初步测定了60种植物的浸提液对其细胞增殖的抑制率。结果表明,8种植物的浸提液对铜绿微囊藻生长的抑制率达到90%以上。其中,广玉兰、龙爪槐和黄杨叶片浸提液对铜绿微囊藻生长的抑制率分别达到97.4%、95.6%和91.2%。通过计算得到培养7d后广玉兰、龙爪槐和黄杨的50%抑制效应质量浓度(EC50)分别为0.52、1.04、5.87g/L,而90%抑制效应质量浓度(EC90)分别为3.79、6.45、9.09g/L。首次发现此3种植物浸提液中富含能抑制铜绿微囊藻细胞增殖的化学物质,可以作为抑藻化感物质的一个重要来源。根据EC50和EC90对培养时间的拟合方程判断,广玉兰和龙爪槐浸提液对铜绿微囊藻的抑制效果较黄杨浸提液更为长效,且由于其抑制效果优于农作物秸秆,具有进一步研究的价值。     

含油污泥及其污染水体中多环芳烃及其急性生物毒性测定

为了更好地控制含油污泥的环境污染,通过实验分析了五种不同来源的含油污泥中多环芳烃(PAHs)的含量、来源以及总毒性当量浓度(TEQ),测定了不同有机溶剂浸提液的急性生物毒性,并对油泥污染水样的PAHs和急性生物毒性进行了分析。研究发现,不同含油污泥中PAHs含量为496.10~4 233.25μg·g~(-1),PAHs总毒性当量(TEQ)为8.41~231.56μg·g~(-1),炼化厂含油污泥中的PAHs主要来源于石油及其精炼产品的热转化,其他含油污泥中的PAHs主要来源于原油本身。正己烷是3种受试有机溶剂中最适合测量含油污泥急性生物毒性的溶剂。被污染水样中PAHs含量为9.68~385.16 ng·mL~(-1),除被清罐油泥污染的水样外,其他油泥污染水样中苯并(a)芘(BaP)未超标,但所有测试水样都具有较高的急性生物毒性,相对发光抑制率最高达到87.46%,大大超过了毒性参照物100 mg·L~(-1)的Zn~(2+)的抑制率。     

壬基酚对鱼、藻、的毒性研究及风险评价

近年来,壬基酚在各种环境介质中被广泛检出,已经成为全球关注的环境污染物。以斑马鱼(Danio rerio)胚胎、羊角月牙藻(Pseudokirchneriella subcapitata)、大型溞(Daphnia magna Straus)为受试生物,研究壬基酚对3种水生生物的急性毒性及对斑马鱼胚胎的慢性毒性作用。在此基础上,依据国内外一些水环境中壬基酚的污染情况,开展了初步的风险评价。结果显示,壬基酚暴露对斑马鱼胚胎的96h半致死浓度(LC_(50))为1.01mg/L,对羊角月牙藻的96hLC_(50)为2.39mg/L,对大型溞的48hLC_(50)为2.75mg/L。壬基酚对斑马鱼胚胎的32d最高无效应浓度(NOEC)为0.04mg/L。风险评价结果显示,壬基酚在一些水环境中具有不同程度的环境风险,部分水环境风险商大于0.10,甚至大于1.00,风险程度为中等到高等,需要引起足够重视。     

EGSB反应器处理产氢发酵液

以厌氧颗粒污泥为接种污泥，对厌氧颗粒污泥膨胀床（EGSB）反应器处理产氢发酵液的启动性能进行了研究。结果表明，在温度为（35±1）℃，水力停留时间（HRT）为6h的条件下，逐渐提高进水COD，经过40d连续运行，EGSB反应器启动成功。容积负荷达到14kgCOD／（m3·d）时，COD去除率约为80％，产气量为26．84L／d，甲烷含量为57．9％。     

响应面分析法优化纳米零价铁铜双金属修复土壤浸提液中Cr(Ⅵ)

采用液相还原法制备出纳米零价铁铜双金属,研究纳米零价铁铜双金属对土壤浸提液中Cr(Ⅵ)的修复作用。利用响应面分析方法,以处理时间、土壤浸提液的pH值和温度3个影响因素,纳米零价铁铜双金属对土壤浸提液中的Cr(Ⅵ)的去除率为响应值进行了3因素3水平的实验设计,得到响应曲面模型。对得到的响应曲面和方差进行分析。结果表明,模型的方差分析得到的F值和R2分别为15.18和0.951 3,处理时间、土壤浸提液的pH值和温度对土壤浸提液中Cr(Ⅵ)去除率的影响是显著的,模型在整个回归区域内拟合程度好,其影响顺序为处理时间土壤浸提液的pH值反应温度。     

对氯苯酚废水处理引起的活性污泥有机毒性

以处理难降解有机污染物对氯苯酚(4-CP)模拟废水的序批式好氧活性污泥系统为研究对象,探讨活性污泥在降解4-CP的过程中污泥有机毒性的形成与空间分布规律,以及污泥有机毒性随时间的变化趋势。处理组污泥用10 mg/L的4-CP模拟废水进行驯化。控制SBR系统的水力停留时间(HRT)和污泥停留时间(SRT)分别为12 h和20 d。结果表明,随着驯化时间的延长,处理组污泥毒性先升高后降低,最终达到稳定状态。在整个运行过程中,处理组污泥毒性始终高于对照组。4-CP的吸附与降解实验表明,污泥外层胞外聚集物(EPS)主要起吸附4-CP且向内层传递的作用,污泥有机毒性主要是由4-CP的降解过程引起,少部分由污染物吸附所致。     

生活污水的臭氧深度处理及其急性毒性

以生活污水处理厂二级生物处理出水为研究对象,利用固相萃取、吸附树脂层析等手段,研究了臭氧氧化过程中进出水及不同分级组分的发光细菌急性毒性的变化,揭示了无机离子浓度对臭氧氧化出水急性毒性的影响,并采用三维荧光光谱对急性毒性相关的物质组分进行了解析。结果表明,在反应时间为15 min,臭氧投加速率为2.1 mg·(L·min)-1,臭氧氧化出水的急性毒性明显下降,出水的急性毒性仅为进水的24.7%。水样不同分级组分的生物毒性测试结果显示,生物处理出水中的亲水性物质和疏水中性物质分别贡献了44.6%和27.8%的毒性当量。当生物处理出水的氯离子含量为75~400 mg·L~(-1)时,经臭氧氧化后,出水的急性生物毒性与氯离子浓度成正相关关系,当生物处理出水的硫酸根离子和硝酸根离子含量分别在150~300 mg·L~(-1)和20~110 mg·L~(-1)变化时,经臭氧氧化后,出水的急性生物毒性变化不大,结合三维荧光光谱的分析结果,臭氧氧化出水中急性毒性物质可能主要存在于芳香族蛋白质类似物(Ⅱ区)和类腐殖酸类物质(Ⅴ区)中。     

高稳定性污泥蛋白发泡剂的发泡特性及应用研究

以污泥蛋白为实验材料，通过加入不同量的稳定剂GP-1，配制成高稳定性污泥蛋白发泡剂，并对高稳定性污泥蛋白发泡剂的发泡特性和影响因素进行研究。结果表明，以污泥蛋白10 mL、水90 mL、GP-1 0.4 g配方组合为研究对象，所制备的泡沫初始体积为770 mL，泡沫泌水时间大于15 h，泡沫半衰期大于64 h，泡沫综合发泡能力为2.2×10⁶ mL·min，泡沫的最佳搅拌时间为5 min，泡沫的泌水时间和泡沫的半衰期都是随着温度的上升而下降，在pH为3～13时泡沫稳定。经过对高稳定性污泥蛋白发泡剂发泡特性研究以及对水泥的胶凝时间、特性进行比较，研制出污泥蛋白泡沫混凝土发泡剂，并制备污泥蛋白泡沫混凝土块；结果表明，当污泥蛋白泡沫混凝土发泡剂的用量分别为0、6、6.8、7.6、8.4和9.2 mL，水泥为200 g时，制备泡沫混凝土块，其密度由2.07 g/cm³下降到0.34 g/cm³，体积由130 cm³ 上升到755 cm³；在泡沫混凝土块脱模后的第1 d、第7 d、第28 d分别称量他们的重量变化情况，结果表明，泡沫混凝土块第1 d和第7 d无重量变化，第28 d的重量明显减轻。该研究为污泥蛋白研制成为泡沫混凝土发泡剂，并应用于屋面隔热、保温建立前期基础。     

PAM对制药污泥脱水性能改善及毒性削减

制药污泥的脱水处理及毒性削减是当前业界的研究热点。以污泥脱水性能(污泥比阻和泥饼含固率)和污泥综合急性毒性为评价指标,对2种不同型号PAM处理污泥的投加量进行优化,讨论了污泥絮凝脱水和毒性削减的机理。研究结果表明,处理100 mL原污泥,当制药污水厂现场使用的德国天使PAM和拓普戴克TOP8321型PAM投加量分别为4mg/L和12 mg/L时,污泥脱水性能达到最佳,此时污泥比阻从0.730×1012cm/g分别降低至0.126×1012cm/g和0.034×1012cm/g,泥饼含固率从16.32%分别提高至46.89%和34.98%;在毒性削减方面,2种混凝剂都可将污泥上清液毒性由微毒降至无毒,但对污泥毒性的削减效果不明显。对2种PAM的处理成本进行估算发现,污水厂现场使用的PAM对处理该制药污泥效果更佳,且费用相对较低,但要大幅度削减制药污泥的毒性需串联相应毒性削减技术和混凝沉淀单元。     

化工污泥基轻质填料的制备及其应用

将化工污泥焚烧灰渣掺入粘土、干燥化工污泥为原料,添加自制无机重金属稳定剂S01,经烘干、预热、焙烧等工艺过程,制备了粒径为10~20 mm的水处理填料。通过单因素实验考察了干污泥添加量、污泥焚烧灰渣添加量、S01添加量、预热时间、烧结温度等工艺条件对填料性能(堆积密度、吸水率)的影响,确定了填料的最佳制备条件:干污泥添加量20%,焚烧灰渣添加量40%,S01添加量5%,预热时间30 min,烧结温度1 150℃。此时,填料的堆积密度为569.11 kg/m3,吸水率为9.84%,重金属浸出浓度远远低于《危险废物鉴别标准浸出毒性鉴别(GB5085.3-2007)》的浓度限值。采用扫描电镜观察了填料表面和内部孔隙特征,发现最佳制备条件下制得的填料表面粗糙多孔,内部具有发达的孔道结构。开展了填料的生物挂膜研究,结果表明,在挂膜启动13 d后,化工污泥基填料滤池的COD和氨氮去除率均趋于稳定,分别达到95.6%和71.8%,该处理效果略优于市售填料。验证了化工污泥基填料应用于生物滤池的可行性。     

Enhancing aerobic digestion potential of municipal waste-activated sludge through removal of extracellular polymeric substance

A protease-secreting bacteria was used to pretreat municipal sewage sludge to enhance aerobic digestion. To enhance the accessibility of the sludge to the enzyme, extracellular polymeric substances were removed using citric acid thereby removing the flocs in the sludge. The conditions for the bacterial pretreatment were optimized using response surface methodology. The results of the bacterial pretreatment indicated that the suspended solids reduction was 18 % in sludge treated with citric acid and 10 % in sludge not treated with citric acid whereas in raw sludge, suspended solids reduction was 5.3 %. Solubilization was 10.9 % in the sludge with extracellular polymeric substances removed in contrast to that of the sludge with extracellular polymeric substances, which was 7.2 %, and that of the raw sludge, which was just 4.8 %. The suspended solids reduction in the aerobic reactor containing pretreated sludge was 52.4 % whereas that in the control reactor was 15.3 %. Thus, pretreatment with the protease-secreting bacteria after the removal of extracellular polymeric substances is a cost-effective and environmentally friendly method.     

Effect of copper in the protistan community of activated sludge

Protists have proved to be an interesting tool for assessing the occurrence of pollution in wastewater treatment systems along with its role in the control of pollution itself through grazing of dispersed bacteria and maintenance of a healthy trophic web in those artificial ecosystems. Two sets of assays were carried on in a bench scale pilot plant in order to study the response of the activated sludge community of protists to the exposure of copper: the first set was carried on with synthetic sewage and the second one with real sewage. The results emphasize the ability of activated sludge biological communities to survive and to react to toxicants and highlight the role of protistan communities as indicators of toxicants entrance in treatment systems.     

Concentrations and specific loads of brominated flame retardants in sewage sludge

Many substances related to human activities end up in wastewater and accumulate in sewage sludge. The present study focuses on two classes of brominated flame retardants: polybrominated diphenyl ethers (BDE28, BDE47, BDE49, BDE66, BDE85, BDE99, BDE100, BDE119, BDE138, BDE153, BDE154, BDE183, BDE209) and hexabromocyclododecane (HBCD) detected in sewage sludge collected from a monitoring network in Switzerland. Mean concentrations (n=16 wastewater treatment plants) were 310, 149, 95 and 17microg per kg dry matter for decaBDE, HBCD, penta- and octaBDE, respectively. These numbers correspond well with other studies from European countries. DecaBDE, HBCD, penta- and octaBDE showed average specific loads (load per connected inhabitant per year) in sludge of 6.1, 3.3, 2.0 and 0.3mgcap(-1)yr(-1), respectively. This is in line with consumption and storage of the compounds in the environment and the anthroposphere. Discrepancies observed for octaBDE and HBCD can be explained by the release from materials where these compounds are incorporated in and/or their degradation during anaerobic sludge treatment. Loads from different types of monitoring sites showed that brominated flame retardants ending up in sewage sludge originate mainly from surface runoff, industrial and domestic wastewater.     

Concentrations and specific loads of UV filters in sewage sludge originating from a monitoring network in Switzerland

Many substances related to human activities end up in wastewater and accumulate in sewage sludge. The present study focuses on the analysis of widely used UV filters 3-(4-methylbenzylidene) camphor (4-MBC), octyl-methoxycinnamate (OMC), octocrylene (OC) and octyl-triazone (OT) in sewage sludge originating from a monitoring network in Switzerland. Mean concentrations in stabilised sludge from 14 wastewater treatment plants were 1780, 110, 4840 and 5510 microg/kg dry matter for 4-MBC, OMC, OC and OT, respectively. Specific loads in sewage sludge show that UV filters originate mainly from private households, but surface runoff and industries may be considered as additional sources. This indicates that besides use for sunscreens and cosmetics UV filters might occur in plastics and other materials and be released to the environment by volatilization or leaching. Differences between the modeled per capita loads of UV filters in sewage sludge and the observed specific loads in sewage sludge are probably due to erroneous figures of production volumes, degradation and sorption during wastewater treatment as well as degradation processes during transport in the sewer or sludge treatment. Thus, further research is needed to elucidate the fate of UV filters after application and release into the environment. Other compounds used as UV filters should be included in future studies.     

Occurrence of polycyclic aromatic hydrocarbons in sewage sludge and their contribution to its toxicity in the toxalert 100 bioassay.

The contribution of polycyclic aromatic hydrocarbons (PAH) present in sewage sludge samples to toxicity was investigated. Chemical analysis using gas chromatography mass spectrometry (GC-MS) and the ToxAlert 100 bioassay, based on the inhibition to Vibrio fischeri, were applied to sludge extracts after purification by column chromatography. The levels of the 16 US EPA PAH analyzed in the sewage sludge samples varied from 17 to 2,030 microg kg(-1). In all samples examined phenanthrene was the most prominent compound. The toxicity data obtained by ToxAlert 100 can be explained by the levels and composition of the different PAH in sewage sludge samples. The present approach can contribute to evaluate the toxicity of sewage sludge.     

Reed beds receiving industrial sludge containing nitroaromatic compounds

Goal, Scope and Background Sweden has prohibited the deposition of organic waste since January, 2005. Since 1 million tons of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a larger degree. One common method in the USA and parts of Europe is the use of wetlands to treat wastewater and sewage sludge. The capacity of reed beds to affect the toxicity of a complex mixture of nitroaromatics in sludge, however, is not fully elucidated. In this study, an industrial sludge containing explosives and pharmaceutical residues was therefore treated in artificial reed beds and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of many pharmaceuticals and explosives, are well known to cause cytotoxicity and genotoxicity. Recently performed studies have also showed that embryos of zebrafish (Danio rerio) are sensitive to nitroaromatic compounds. Therefore, we tested the sludge passing through constructed wetlands in order to detect any changes in levels of embryotoxicity, genotoxicity and dioxin-like activity (AhR-agonists). We also compared unplanted and planted systems in order to examine the impact of the root system on the fate of the toxicants. Methods An industrial sludge containing a complex mixture of nitroaromatics was added daily to small-scale constructed wetlands (vertical flow), both unplanted and planted with Phragmites australis. Sludge with an average dry weight of 1.25%, was added with an average hydraulic loading rate of 1.2 L/day. Outgoing water was collected daily and stored at −20°C. The artificial wetland sediment was Soxhlet extracted, followed by clean-up with multi-layer silica, or extracted by ultrasonic treatment, yielding one organic extract and one water extract of the same sample. Genotoxicity of the extracts was measured according to the ISO protocol for the umu-C genotoxicity assay (ISO/TC 147/SC 5/WG9 N8), using Salmonella typhimurium TA1535/pSK1002 as test organism. Embryotoxicity and teratogenicity were studied using the fish egg assay with zebrafish (Danio rerio) and the dioxin-like activity was measured using the DR-CALUX assay. Chemical analyses of nitroaromatic compounds were performed using Solid Phase Micro Extraction (SPME) and GC-MS. Results Organic extracts of the bed material showed toxic potential in all three toxicity tests after two years of sludge loading. There was a difference between the planted and the unplanted beds, where the toxicity of organic extracts overall was higher in the bed material from the planted beds. The higher toxicity of the planted beds could have been caused by the higher levels of total carbon in the planted beds, which binds organic toxicants, and by enrichment caused by lower volumes of outgoing water from the planted beds. Discussion Developmental disorders were observed in zebrafish exposed directly in contact to bed material from unplanted beds, but not in fish exposed to bed material from planted beds. Hatching rates were slightly lower in zebrafish exposed to outgoing water from unplanted beds than in embryos exposed to outgoing water from planted beds. Genotoxicity in the outgoing water was below detection limit for both planted and unplanted beds. Most of the added toxicants via the sludge were unaccounted for in the outgoing water, suggesting that the beds had toxicant removal potential, although the mechanisms behind this remain unknown. Conclusions During the experimental period, the beds received a sludge volume (dry weight) of around three times their own volume. In spite of this, the toxicity in the bed material was lower than in the sludge. Thus, the beds were probably able to actually decrease the toxicity of the added, sludge-associated toxicants. When testing the acetone extracts of the bed material, the planted bed showed a higher toxicity than the unplanted beds in all three toxicity tests. The toxicity of water extracts from the unplanted beds, detected by the fish egg assay, were higher than the water extracts from the planted beds. No genotoxicity was detected in outgoing water from either planted or unplanted beds. All this together indicates that the planted reed beds retained semi-lipophilic acetone-soluble toxic compounds from the sludge better than the unplanted beds, which tended to leak out more of the water soluble toxic compounds in the outgoing water. The compounds identified by SPME/GC in the outgoing water were not in sufficient concentrations to have caused induction in the genotoxicity test. Recommendations and Perspectives This study has pointed out the benefits of using constructed wetlands receiving an industrial sludge containing a complex mixture of nitroaromatics to reduce toxicity in the outgoing water. The water from planted, constructed wetlands could therefore be directed to a recipient without further cleaning. The bed material should be investigated over a longer period of time in order to evaluate potential accumulation and leakage prior to proper usage or storage. The plants should be investigated in order to examine uptake and possible release when the plant biomass is degraded. This article has been developed on the basis of a presentation given at the Annual meeting of SETAC Europe German Language Branch 2004 in Aachen. ESS-Submission Editor: Dr. Ludek Blaha (blaha@recetox.muni.cz)     

Emission characteristics for co-combustion of leather wastes,sewage sludge,and coal in a laboratory-scale entrained flow tube furnace

Four different mixed fuels consisted of leather waste, coal, and sewage sludge were combusted in a lab-scale entrained flow fluidized bed furnace. The influence of blending ratio on emission characteristics of SO₂, NO_x, HCl, particulate matter (PM), heavy metals, and polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied. Results showed that the mixing of coal with sewage sludge had a complex effect on the emission characteristics. On the one hand, with more sewage sludge blending in the mixed fuel, the acid gas pollutant (SO₂, NO_x) decreased a lot, and the recovery of volatile heavy metals (Cd, Pb) increased at the same time. Furthermore, the leaching toxicity of Cr in the fly ash and bottom ash went down below the national standard with the adding of sewage sludge. On the other hand, the mixing of sewage sludge which consisted of more ash content resulted in the increase of the PM emission. Moreover, the high content of Cu and chlorine in the sewage sludge can promote the formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) when the fuel 3 and 4 were combusted. Most importantly, the concentration of toxic PCDD/Fs in the flue gas produced from fuel 3 and fuel 4 was successfully controlled down below 0.20 ng I-TEQ/Nm³ by the active carbon.

     

Comparison of sewage sludge toxicity to plants and invertebrates in three different soils

Understanding the effect of soil type on the overall toxicity of sewage sludge is one of the most important issues concerning environmental risks associated with the sewage sludge land application. The aim of the study was to determine the influence of different soils (sandy, loamy and OECD soil) on sewage sludges toxicity in relation to plants (Lepidium sativum, Sorghum saccharatum, Sinapis alba) and an invertebrate species (Heterocypris incongruens). The most evident negative influence of sewage sludges on root growth was observed in the case of OECD soil. The EC(50) values determined on the basis of the root growth inhibition of all tested plants were in the range 0.1-6.4%, 0.03-9.4% and 6.6-22.1% (% of sewage sludgekg(-1) soil) for OECD, sandy and loamy soil, respectively. Soil type also affects the sewage sludge toxicity in relation to H. incongruens. The LC(50) (mortality) values ranged from 0.26% to 11.5% depending on the sludge tested. For EC(50) (growth inhibition) values ranged from 10.7% to 36.2%.     

不同pH控制策略下剩余污泥中NH4^＋-N、PO4^3--P、COD溶出研究

污水处理厂的剩余污泥中富含氮、磷、COD,在其水解酸化过程中对pH条件进行控制,使污泥中的氮、磷、COD溶出到上清液中并进行回收利用是可行的。在22～25℃的温度条件下,1#反应器中剩余污泥先调节为酸性（pH=3）,在实验第8 d氨氮、磷酸盐溶出量最多后调节为碱性（pH=10）;3#反应器中剩余污泥先调节为碱性（pH=10）,在实验第8 dCOD溶出量最多后调节为酸性（pH=3）;2#反应器为对照实验,pH不进行调节。结果表明：若要以回收污泥中的氨氮、磷酸盐为主,剩余污泥由碱性（pH=10）调节为酸性（pH=3）优于由酸性（pH=3）调节为碱性（pH=10）;若要回收污泥上清液中的COD为主,剩余污泥由酸性（pH=3）调节为碱性（pH=10）优于由碱性（pH=10）调节为酸性（pH=3）。