超声与碱预处理低有机质剩余污泥特性分析

以某城市污水处理厂低有机质剩余污泥（VSS/SS为0.42）为对象,通过实验研究了超声与碱（NaOH和CaO）预处理对其特性的影响,分析了加碱和未加碱时污泥上清液中pH值、ORP（氧化还原电位）、SCOD、TP和NH₃-N等随超声处理时间的变化规律。结果表明,在超声处理30～120 min范围内,超声加碱处理可使污泥上清液中ORP明显下降;超声加碱处理可明显提高污泥上清液中的SCOD释放量,且加NaOH比加CaO更为明显;NaOH加超声处理可促进污泥中TP的释放,但CaO加超声处理则与此相反;无论是否加碱,超声处理对污泥上清液中NH₃-N释放影响较小;超声加碱处理剩余污泥可明显改善污泥絮体,使其更为紧密。     

低溶解氧污泥微膨胀污染物去除性能的研究

为了研究低溶解氧微膨胀状态下污染物的去除效果,采用SBR反应器,平均DO浓度为0.5～0.9 mg/L,通过好氧/缺氧(O/A)的运行方式,对污染物处理效果进行研究。结果表明：低溶解氧丝状菌污泥微膨胀状态下,SVI可稳定控制在200 mL/g左右,出水SS含量很低,COD去除率在80%以上,氨氮去除率90%以上,除磷效率在90%之上,出水水质良好,同时可以节约曝气量约46.7%。低溶解氧微膨胀状态下,可保证出水处理效果,污泥沉降性能影响小,同时可以节约动力费用。     

同步硝化反硝化工艺中DO浓度对N2O产生量的影响

采用序批式生物膜反应器（SBBR）,在连续曝气全程好氧的运行条件下,考察不同溶解氧浓度对同步硝化反硝化脱氮性能及N2O产量的影响。控制溶解氧浓度恒定在1、2、2.5和3 mg/L。结果表明,DO为2 mg/L和2.5 mg/L时,氨氮去除率分别为97.9%和98.5%,同步硝化反硝化率均为99%。DO为2 mg/L时,系统中N2O产生量最低,为0.423 mg/L,占氨氮去除量的1.4%;DO为3 mg/L时N2O的产生量最高,为2.01 mg/L,是DO为2 mg/L时的4.75倍。系统中亚硝酸盐的存在可能是高溶解氧条件下N2O产量增加的主要原因,同步过程中没有NOx-的积累即稳定的SND系统有利于降低生物脱氮过程中N2O的产生量。     

COD对强化生物除磷系统的影响及OUR的变化规律

以实际生活污水为研究对象,在SBR系统中采用厌氧/好氧运行方式,考察强化生物除磷(EBPR)系统中好氧阶段COD浓度对聚磷菌除磷性能的影响以及不同好氧阶段COD浓度下的OUR变化规律.实验分4个阶段进行,分别为不投加外碳源、厌氧结束时投加不同体积的乙酸钠作为外碳源,使COD分别提高50、100和300mg/L.4种工况...     

水体低氧的早期暴露对青鳉(Oryzias latipes)后期的生长、性别比和繁殖能力的影响

水体低氧已是全球性生态问题,常以季节性、偶发性和昼夜间等不同形式存在于不同的水体中。长期低氧可影响鱼类正常的生长和繁殖,但鱼类早期生活阶段暴露于不同形式的低氧后,后期的生长和繁殖是否会受到不利影响,目前研究甚少。本研究在实验室模拟了连续低氧(2.8 mg·L~(-1)DO)(H1)、昼夜低氧(H2)和发生在胚胎器官形成时期的偶发性低氧(H3)等3种情景对青鳉胚胎的发育影响,评估了这一早期暴露对青鳉后期的生长、存活和繁殖的影响。我们发现,3种低氧方式都可以显著延长青鳉胚胎的孵化周期,引起胚胎卵黄囊吸收和鱼鳔发育异常;暴露结束120 d后,H1组青鳉成鱼的畸形率显著升高、存活率和生长速度都显著下降;H1、H2和H3组中成鱼的雌雄比都发生了改变,鱼群中以雄鱼为主,且产卵量和受精率都显著下降。结果表明,鱼类早期胚胎发育阶段所受到的低氧暴露可对后期生长和繁殖产生不利影响,对子代补充和种群稳定产生重要影响;鱼类关键发育期所经历的低氧事件,以及昼夜低氧事件所产生的生态后果不容忽视。     

Enhanced effect of HAH on citric acid-chelated Fe(II)-catalyzed percarbonate for trichloroethene degradation

This work demonstrates the impact of hydroxylamine hydrochloride (HAH) addition on enhancing the degradation of trichloroethene (TCE) by the citric acid (CA)-chelated Fe(II)-catalyzed percarbonate (SPC) system. The results of a series of batch-reactor experiments show that TCE removal with HAH addition was increased from approximately 57 to 79% for a CA concentration of 0.1 mM and from 89 to 99.6% for a 0.5 mM concentration. Free-radical probe tests elucidated the existence of hydroxyl radical (HO^•) and superoxide anion radical (O₂ ^•-) in both CA/Fe(II)/SPC and HAH/CA/Fe(II)/SPC systems. However, higher removal rates of radical probe compounds were observed in the HAH/CA/Fe(II)/SPC system, indicating that HAH addition enhanced the generation of both free radicals. In addition, increased contribution of O₂ ^•- in the HAH/CA/Fe(II)/SPC system compared to the CA/Fe(II)/SPC system was verified by free-radical scavengers tests. Complete TCE dechlorination was confirmed based on the total mass balance of the released Cl⁻ species. Lower concentrations of formic acid were produced in the later stages of the reaction for the HAH/CA/Fe(II)/SPC system, suggesting that HAH addition favors complete TCE mineralization. Studies of the impact of selected groundwater matrix constituents indicate that TCE removal in the HAH/CA/Fe(II)/SPC system is slightly affected by initial solution pH, with higher removal rates under acidic and near neutral conditions. Although HCO₃ ⁻ was observed to have an adverse impact on TCE removal for the HAH/CA/Fe(II)/SPC system, the addition of HAH reduced its inhibitory effect compared to the CA/Fe(II)/SPC system. Finally, TCE removal in actual groundwater was much significant with the addition of HAH to the CA/Fe(II)/SPC system. The study results indicate that HAH amendment has potential to enhance effective remediation of TCE-contaminated groundwater.

     

Health risk assessment of exposure to organic matter from the use of reclaimed water in toilets

To estimate the carcinogenic and non-carcinogenic risks of six volatile organic compounds (VOCs) found in reclaimed water used for flushing toilets, a probabilistic health risk assessment based on Monte Carlo simulations was used. Before Monte Carlo simulations, the contaminant volatilization model was applied to estimate the concentration of the pollutants in air. Moreover, a questionnaire was used to acquire daily exposure time and the Batch Fit tool of Crystal Ball software was applied to find the best-fitting distribution of a part of the input parameters. The risk analysis indicated that the health risks from six VOCs were lower than the negligible risk level (1?×?10^?8) in all cases, and the health risk for females was slightly higher than that for males. Overall, exposure to organic pollutants in reclaimed water during toilet flushing does not currently pose a significant carcinogenic risk to humans. In this study, we want to provide some information on the health risk from reclaimed water used for toilet flushing in China and hope that it will be useful to promote the application of reclaimed water in water-deficient areas.     

基于指标规范值的环境质量的指数幂乘积指数公式

传统的环境质量指数幂乘积指数的分级标准值随指标不同和指标数目不同而不同,因而综合指数的分级标准值不能规范和统一.在适当设定指标参照值和指标值的规范变换式基础上,使同类环境不同指标的同级标准的规范值差异尽可能小,而不同标准的指标规范值差异尽可能大,从而可以认为,用规范值表示的同类环境的各指标皆等效于某个规范指标,因而同类环境的任意m项指标的指数幂乘积综合指数可以有共同的分级标准值,使基于指标规范值的环境质量指数幂乘积指数公式具有普适性、可比性和通用性.     

双向旋流污水净化器处理溢流污水

介绍了双向旋流絮凝沉淀一体化污水净化器的结构特点及运行机理,其具有双旋流室和悬浮过滤层的结构提高了对污水的净化效率。利用双向旋流净化器对镇江市溢流污水进行处理,对装置的分离性能和运行的稳定性进行了研究,实验结果表明,双向旋流器在絮凝剂PAC投加量为150 mg/L,入口流量在1.5 m3/h,水力停留时间为10 min条件下对溢流污水的处理效果较好,COD、SS、TN和TP的去除率分别为70.0%、97.7%、71.2%和78.6%。装置连续运行3 h对COD和SS的平均去除率分别在65%和96%以上。     

太湖水体附着细菌和浮游细菌的丰度与分布特征

为了探讨太湖水体附着细菌及浮游细菌丰度的变化规律,明确细菌丰度与环境因子的关系,应用荧光显微技术对太湖4个湖区细菌丰度及分布特征进行了研究,并探讨了其与总氮(TN)、总磷(TP)、叶绿素a(Chla)、总悬浮颗粒物(TSS)等环境因子之间的关系.结果表明,太湖水体中附着细菌占优势,占总细菌的65％(总细菌平均值为6.53×106cells/mL,附着细菌平均值为4.25×106 cells/mL,浮游细菌平均值为2.28 × 106 cells/mL);附着细菌与浮游细菌数丰度具有相似的时空分布规律,附着细菌与浮游细菌丰度都是河口区(10#)最高,其次梅梁湾(3 #)、湖心区(8#)和东太湖(24#)较低;春夏季高,秋冬季低;水温、TP对太湖水体中附着细菌及附浮游细菌的丰度影响比较大,它们与水体中附着细菌丰度及附浮游细菌均呈显著的正相关(p＜0.05).太湖不同湖区附着细菌及浮游细菌的数量空间差异是由太湖不同湖区生态环境的异质性引起的.