The difference of morphological characteristics and population structure in PAO and DPAOgranular sludges

We examined how long-term operation of anaerobic–oxic and anaerobic–anoxic sequencing batch reactors(SBRs) affects the enhanced biological phosphorus removal(EBPR)performance and sludge characteristics. The microbial characteristics of phosphorus accumulating organism(PAO) and denitrifying PAO(DPAO) sludge were also analyzed through a quantitative analysis of microbial community structure. Compared with the initial stage of operation characterized by unstable EBPR, both PAO and DPAO SBR produced a stable EBPR performance after about 100-day operation. From day 200 days(DPAO SBR)and 250 days(PAO SBR) onward, sludge granulation was observed, and the average granule size of DPAO SBR was approximately 5 times larger than that of PAO SBR. The DPAO granular sludge contained mainly rod-type microbes, whereas the PAO granular sludge contained coccus-type microbes. Fluorescence in situ hybridization analysis revealed that a high ratio of Accumulibacter clade I was found only in DPAO SBR, revealing the important role of this organism in the denitrifying EBPR system. A pyrosequencing analysis showed that Accumulibacter phosphatis was present in PAO sludge at a high proportion of 6%,whereas it rarely observed in DPAO sludge. Dechloromonas was observed in both PAO sludge(3.3%) and DPAO sludge(3.2%), confirming that this organism can use both O_2 and NO_3~- as electron acceptors. Further, Thauera spp. was identified to have a new possibility as denitrifier capable of phosphorous uptake under anoxic condition.     

Organochlorine compounds and polycyclic aromatic hydrocarbons in surface sediment from Baiyangdian Lake, North China： Concentrations, sources profiles and potential risk

Organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs),and polycyclic aromatic hydrocarbons(PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river(Fuhe River) in North China.Total concentrations of OCPs,PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng/g,2.3 to 197.8 ng/g,and 101.3 to 6360.5 ng/g,respectively.The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake.For hexachlorocyclohexane(HCHs) and dichlorodiphenytrichloroethanes(DDTs),α-HCH and p,p-DDT were predominant isomers;while for PCBs,PCB 28/31,PCB 40/103,PCB 60,PCB 101,and PCB 118 were predominant congeners.Possible sources derived from historical usage for OCPs and incomplete combustion fuel,wood,and coal and exhaustion of boats or cars for PAHs.Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.     

间歇曝气模式下曝气量对短程硝化恢复的影响

采用SBR反应器在间歇曝气模式下对搁置2个月的短程硝化污泥进行恢复,控制曝气量分别为120、100、80和60L·h-1,在温度为25℃、交替好氧/缺氧时间比为30 min/30 min条件下处理实际生活污水,进水氨氮浓度为50~80 mg·L~(-1),出水氨氮浓度分别在第12、18、21和21周期之后稳定在5 mg·L~(-1)以下,氨氮去除率均高达95.00%左右;第30、35、38和42周期时,亚硝氮积累浓度分别达到20.83、22.81、21.50和20.73 mg·L~(-1),硝氮出水浓度均低于0.5 mg·L~(-1),亚硝积累率均高于99%,氨氧化菌(AOB)活性最终均稳定在100.00%左右,而亚硝酸盐氧化菌(NOB)活性逐渐被抑制,4种曝气量下均成功实现了短程硝化的恢复.     

山西省2015年细颗粒物的污染状况和空间分布

大气污染因其对人体健康、生态环境和气候变化的影响而成为全球关注的环境问题,细颗粒物（PM_2.5）是雾霾产生的主要原因之一。为全面掌握山西省细颗粒物的污染状况与空间分布格局,本文运用统计学方法和Arc GIS技术,根据环境空气质量评价技术规范,对2015年山西省57个空气质量指数监测站提供的PM_2.5实时数据进行处理分析。结果表明：山西省PM_2.5的浓度有明显的季节性变化特征,由高到低依次为冬、春、秋、夏;PM_2.5月平均浓度最高值分别出现在1月和12月,且高值中心都位于运城;在空间分布上则表现为南部高于北部。全省11个地市级城市有9个超过国家二级标准,超标指数达到72%。聚类分析结果表明：山西省城市可以分为两大类,一类为产业结构转型良好的城市,如阳泉、朔州、吕梁、大同;另一类为第二产业发展粗放,工业污染严重的区域。     

建设项目环境影响报告表编制需重点关注的问题

随着国家对建设项目环境影响评价工作的要求不断规范和完善,为提高环境影响报告表的编制质量,为环境管理部门审批项目提供科学依据。本文就目前在编制建设项目环境影响报告表工作中,分析和探讨了几个需要特别重点关注的问题,供有关人员借鉴。     

环境监测支持溢油事故处置的要点

本文以实例探讨了溢油事故处置中进行环境监测支持的要点,重点介绍溢油污染事故监测的采样布点以及分析方法的选择,并提出了通过加强应急监测队伍和监测能力的建设来提高处理此类事故的能力.     

汉江流域水污染现状及污染源调查

评价了汉江流域水质污染现状：汉江流域干流水质好于支流,从上游至下游污染状况逐渐上升,主要污染物为COD、TP、NH3-N,污染特征为有机污染型。对汉江流域污染源进行了调查：汉江流域面源污染大于点源,排放负荷较大的是农业地表径流、城镇生活污水、畜禽养殖。     

低强度超声波强化SBR处理生活污水

通过设置超声波(ultrasound,US)的SBR反应器(sequence batch reactor,SBR)与对照反应器的对比试验,研究了超声波对SBR处理生活污水的强化效果.结果表明,采用强度0.3 W·cm^-2的超声波,每隔8h取SBR反应器中10%的污泥进行10min辐射处理,对COD的总去除率提高3%～6%,其出水COD与对照反应器的出水相比降低了40%～53%,通过该辐射处理有效提高了SBR反应器对模拟生活污水的高负荷冲击和有毒物质冲击的耐受能力.对于实际生活污水,设置超声强化使污泥耗氧呼吸速率(oxygen uptake rate,OUR)增加14%左右,有效提高了微生物对难降解有机物质的分解能力.对污泥沉降性能的研究表明,超声波强化会引起污泥的SVI值升高,但升高的幅度仅为5%左右,不会对系统的沉降性能造成显著影响.根据电镜观测以及种群结构分析发现,超声波对细胞产生了损伤作用,其表面出现了明显的皱褶,但是活性污泥种群结构并未发生显著变化.通过对2个反应器中活性污泥的呼吸动力学分析表明,设置US反应器中活性污泥对底物具有更高的利用率.     

广州大学城大气PM2.5量浓度与影响因素

选择广州大学城代表性学生宿舍、教室、食堂等多个室内采样点及几个室外采样点,准确测定各采样点大气中PM25的质量浓度,分析各室内和室外采样点大气中PM25污染程度及分布特征;根据同步记录的气象数据,分析评价气象因子对大气PM25质量浓度的影响.     

基于GIS的长沙市洪涝灾害风险动态评估

运用GIS技术的空间分析与建模功能构建洪涝灾害风险评估模型,以长沙市地理基础数据、遥感数据、气象水文、社会统计数据为基础,从洪涝灾害的危险性、暴露性、敏感性三个角度出发,对长沙市洪灾风险进行动态评价.结果表明：与1994年相比,2010年长沙市洪灾敏感性有所增加,暴露性上升,洪灾风险增大;从空间分布上看,长沙市区及望城区由于地势平坦,湘江干流贯穿其中,加之经济发达,因而洪灾风险较高;而西部的宁乡县和东部的浏阳市洪灾风险较低;提出了有针对性的防洪措施.该评价结果与实际情况相符,可为洪灾风险管理与决策提供科学依据.