室内模拟BPRB修复阿特拉津污染地下水

设计了新型生物可渗透反应墙(BPRB)用于处理被污染的地下水。以阿特拉津为污染物,装填固定有阿特拉津降解菌(Pseudomonas W4)的磷酸化聚乙烯醇(PPVA)生物活性材料介质,前半部分以草炭土-PPVA/砂子为填料,以长期稳定地释放C、P;后半部分以珍珠岩-PPVA/砂子为填料,消耗草炭土-PPVA释放的C、P。选择V(PPVA生物活性材料)∶V(砂子)=1∶1的比例安装BPRB。在BPRB内设置曝气井,供氧方式为连续空气曝气,整个BPRB内DO质量浓度大于3 mg/L。BPRB模拟槽共运行140 d,累计进水1 213.6 L,共去除阿特拉津(19.35±1.00)g,出水中始终未检出阿特拉津。试验结果表明,在不额外添加碳源、磷源的条件下,BPRB能够长期稳定修复阿特拉津污染地下水。     

反硝化细菌去除铀矿山废水中硝酸盐

为了从不同环境中筛选得到反硝化能力强的菌株,研究碳源、温度、pH、C/N和铀浓度对菌株脱氮作用的影响,在最佳条件下得到菌株的生长曲线。结果表明：筛选得到了3株高效的反硝化细菌,菌株YWSY21在以无水乙酸钠为最佳碳源时,硝酸盐氮去除率达到97.11%,菌株4和5以柠檬酸钠为最佳碳源时对硝酸盐氮的去除率大于95%。Klebsiella variicola strain 21在温度26.31 ℃、pH=5.74、C/N=12.95最佳条件下,硝酸盐氮去除率为90.77%;Pseudomonas nitroreducens strain 4在温度25.39 ℃、pH=5.90,C/N=10.16最佳条件下,硝酸盐氮去除率为89.27%。菌株5在5种铀浓度下,NO3--N的去除率均大于85%。在最佳生长条件时,菌株4最优脱氮条件下的生长曲线具有较高的生长活性。为铀矿山硝酸盐废水的生物修复提供了菌源保障。     

钙铁基磷酸盐作为PRB反应介质修复锰污染地下水试验

采用溶胶—凝胶法制备了一种新型的钙铁基磷酸盐复合材料(CIP),并采用静态吸附试验法探究了pH、反应时间、锰初始浓度及反应温度等因素对其吸附水溶液中Mn(Ⅱ)的影响。结果表明,CIP吸附水溶液中锰的最佳pH为5,CIP对水溶液中Mn(Ⅱ)具有良好的吸附性能,可作为去除水溶液中锰的PRB反应介质。CIP对水溶液中Mn(Ⅱ)的吸附行为符合Langmuir吸附等温线模型和准二级动力学模型,最大理论吸附量为66.22mg/g。热力学分析结果表明,CIP对Mn(Ⅱ)的吸附是一个自发、吸热和熵增的过程。     

电动联合可渗透反应墙强化修复重金属污染土壤研究进展

已有大量研究证明电动（EK）-可渗透反应墙（PRB）联合技术能用于重金属污染土壤的修复,但其修复效率低且能耗高,还可能导致聚焦效应等问题,因此深入EK-PRB在强化修复方面的研究是十分必要的。简述了EK-PRB技术的原理,介绍了EK-PRB技术的主要影响因素,归纳了EK-PRB强化修复方法的优缺点和修复效果,介绍了EK-PRB技术的研究进展,并对该技术强化修复重金属进行了展望,指出深入探究的方向,以便为EK-PRB修复多种重金属污染土壤的实际应用打下基础。     

废弃生物质热解的两种反应模型对比研究

建立了废弃生物质热解的一级反应、平行反应两种模型。根据实验分别确定了动力学参数:反应的表观活化能E和表观频率因子A.两种模型预测值与实验测量值进行比较,表明平行反应机理模型更适合废弃生物质热解的反应机理.     

柴油污染地下水修复生物反应墙中功能微生物数量及群落多样性

利用功能微生物、泥炭和含水层介质构建生物反应墙原位修复柴油污染地下水,系统经调试稳定后运行80 d,目标污染物去除率为83.60%～99.85%.运行期结束.采用荧光素一最大或然数和Biolog方法研究了生物墙内不同位置处功能微生物的数量及群落多样性.结果表明:墙体内各处均能保持较高的功能微生物数量,且微生物群落的物种数、丰富度、均一性、碳源利用性以及代谢特征均相似;但随着生物墙深度的增加,功能微生物比例有所下降,微生物群落略显丰富,但均一性略差,碳源利用倾向略微不同.生物反应墙原位修复地下水时,功能微生物能够长期保持较高的数量、较好的降解性能和稳定的群落多样性;但随着墙体深度的增加,营养结构发生了改变,导致微生物群落结构略显不同.     

家常方法去除菠菜中农药残留的研究

通过实验,探寻一组对菠菜中农药残留去除的家常处理方法组合.结果表明,洗涤剂浸泡、漂洗和烫漂对菠菜中残留农药都有一定的去除效果,去除效果优化组合为2%洗涤剂浸泡15min 后,用自来水漂洗2次,每次1min,再用沸水烫漂1min.     

黄壤土土地处理系统去除N·P效果的研究

通过实验室构建的黄壤土土地处理系统模型,结合试验数据研究了黄壤土土地处理系统在不同试验条件下对氮、磷的去除效果.结果表明,50cm高的黄壤层可以实现对氮、磷等污染物的有效去除.     

Performance of a PRB for the Remediation of Acidic Groundwater in Acid Sulfate Soil Terrain

Contaminated groundwater resulting from pyrite oxidation of acid sulfate soils (ASSs) is a major environmental problem in coastal Australia. A column test was carried out for an extended period with recycled concrete to study the efficiency of the reactive materials for neutralizing acidic groundwater. Results show that the actual acid neutralization capacity of the recycled concrete could decrease to less than 50% of the theoretical value due to armoring effects. Nevertheless, the performance is good as a spot treatment in ASS Terrain using a near-zero cost waste product. Based on the test results and site characterization, a permeable reactive barrier (PRB) with recycled concrete was designed and installed in ASS terrain on the Shoalhaven River floodplain, southeastern, Australia in October 2006. The performance of the PRB was studied over two and half years to assess the potential of recycled concrete (1) to neutralize the groundwater acidity and (2) to remove the dissolved heavy metals such as iron and aluminum from in situ acidic groundwater. To date, performance monitoring of the PRB shows that recycled concrete can successfully improve the pH of groundwater from acidic to mildly alkaline. In addition, it successfully removes groundwater iron and aluminum. Results reported here also reveal a slow decrease in the performance of the PRB due to armoring effects probably caused by precipitation of iron and aluminum on the surface of the reactive recycled concrete materials.     

地下水中硝态氮自然衰减的实验研究

[目的]研究地下水中硝态氮的自然衰减.[方法]以黄土、粉质粘土、细砂和粉砂为模拟含水层介质,通过密封浸泡实验研究了不同环境条件下地下水中硝态氮的自然衰减过程.[结果]化学还原和生物反硝化作用是硝态氮总童减少的重要途径,其中以化学还原为主,生物反硝化为辅;在原生态环境(不加化学试剂)条件下,硝态氮总量减少率为25.70%～39.90%,即地下水的自净能力较差,造成了硝态氮的积累;在强化化学还原作用条件下,地下水中硝态氮总量的减少率是原生态环境下的2倍以上.[结论]该研究为地下水氮污染防治提供了理论基础和技术支持.     

天然沸石去除地下水中氨氮的研究

针对地下水中氨氮(NH<,4>-N)污染,采用天然沸石进行了试验研究,探讨了沸石种类、振荡强度、pH、吸附等温线等因素对去除地下水中氨氮的影响.结果表明,天然沸石对NH<,4>-N具有"快速吸附、缓慢平衡"的特点,浙江缙云沸石对地下水中NH<,4>-N具有较好的去除能力.当反应时间≤3 h,高振荡强度(200 r/min)的NH<,4>-N去除率大于低振荡强度(100 r/min)的;振荡强度显著影响NH<,4>-N的去除效果.当pH介于2.59～10.66时,去除率为74.23%～93.71%.中性初始pH(5.76～8.55)利于NH<,4>-N的吸附去除,酸性(pH≤2.59)导致去除率略有下降,而碱性(pH≥10.66)致使去除率急剧下降.缙云沸石的Langmiur吸附等温公式为:Q=0.964 8μ/(1+0.181 0μ),而Freundlich吸附公式为:Q=0.815 8μ0.576 2,椎荐采用后者.     

Factorial Design Approach to Investigate the Effects of Groundwater Cooccurring Solutes on Arsenic Removal by Electrocoagulation

Effects of groundwater cooccurring solutes such as phosphate (PO4), silicate (SiO3), bicarbonate (HCO3), calcium (Ca), and iron (Fe) on arsenic removal were investigated in this study. Investigation by two-level full-factorial designed experiments revealed that PO4 and SiO3 have negative effect on arsenic removal, whereas HCO3 has negligible positive effect. The effects of Ca and Fe present in groundwater have positive effect on arsenic removal by electrocoagulation (EC). Hypothesis testing at 5% significance level suggests that alkalinity (HCO3) is not an important parameter in arsenic removal by EC in naturally occurring pH range of water.     

Simultaneous Removal of Phenol and Nitrate in an Anaerobic Bioreactor

Phenol and nitrate are two major pollutants simultaneously occurring in several industrial wastewaters. In this study, a 110-day gradual enrichment of an anaerobic culture has been carried out at 25°C in an anaerobic bioreactor for continuously treating a synthetic wastewater containing 600?mg/L phenol and 430?mg/L?NO3?–N. The results showed that the enriched culture can utilize phenol as a sole electron donor and nitrate as a sole electron acceptor. At the end of the enrichment (on Day 110), 93.3% of phenol and 98.0% of NO3?–N were simultaneously removed at a hydraulic retention time of 20.25?h in the anaerobic bioreactor. The removal of 1?g?NO3?–N required about 3.19?g chemical oxygen demand as the electron donor. Batch tests further revealed that cresol, nitrophenol, and monochlorinated phenol (MCP) could exert detrimental influences on the treatment abilities of the enriched culture. However, the inhibitory effects of cresol were impermanent, as compared to those of nitrophenol and MCP. In order to operate the anaerobic bioreactor steadily, high concentrations of cresol should be diluted before being fed while the existence of nitrophenol and MCP in the bioreactor should be avoided.     

羟基磷灰石复合材料对地下水中铀吸附去除研究进展

铀矿山尾矿库周边地下水在铀矿的风化、淋滤、渗漏等作用下,给地下水和人类带来长期的健康隐患。可渗透反应墙(PRB)作为一种原位修复技术,具有无动力运行、环境影响小和成本低等优点,已经在地下水污染修复中得到了应用。羟基磷灰石(HAP)因具有成本低、原料广泛、生物相容性等优点,成为去除地下水中铀废水的最具潜力介质材料。综述了羟基磷灰石在处理含铀废水中的影响因素,主要包括羟基磷灰石制备方法、改性方法,对含铀废水去除影响研究。并对羟基磷灰石除铀进行机理分析,包括羟基磷灰石形貌、铀溶液pH、共存阴离子等对铀的去除影响。羟基磷灰石(HAP)因具有成本低、原料广泛、生物相容性等优点,成为去除地下水铀的最具潜力介质材料。     

Effect of In-Lake Water Quality on Pollutant Removal in Two Ponds

An extensive field study examined pollutant removal in two regional wet detention ponds near High Point, N.C. Substantial differences in influent pollutant concentrations between the ponds caused significant differences in pond water quality and pollutant removal efficiency. In Davis Pond, influent fecal coliform and nutrient concentrations were high because of several large dairy farms in the watershed, resulting in hypereutrophic conditions as evidenced by high chlorophyll-a concentrations, high midday pH values and supersaturated midday oxygen concentrations. In Piedmont Pond, influent fecal coliform and nutrient concentrations were much lower, resulting in mesotrophic to slightly eutrophic conditions. Both ponds thermally stratified and developed an anaerobic hypolimnion. In Davis Pond, annual pollutant removal efficiencies for total suspended solids, volatile suspended solids, total organic carbon, total phosphorus, dissolved phosphorus, nitrate∕nitrite, total ammonia nitrogen, and total nitrogen were 56%, 32%, 15%, 41%, 54%, 16%, 2%, and 11%, respectively. In Piedmont Pond, annual pollutant removal efficiencies were 20%, 30%, 27%, 40%, 15%, 66%, ?64%, and 36%, respectively.     

Development of a Response Surface for Prediction of Nitrate Removal in Sulfur–Limestone Autotrophic Denitrification Fixed-Bed Reactors

Sulfur–limestone autotrophic denitrification (SLAD) processes are very efficient for treatment of ground or surface water contaminated with nitrate. However, detailed information is not available on the interaction among some major variables on the design and performance of the SLAD process. In this study, the response surface method was used by designing a rotatable central composite test scheme with 12 SLAD column tests. A polynomial linear regression model was set up to quantitatively describe the relationship of the effluent and influent nitrate–nitrogen concentration and hydraulic retention time (HRT) in the SLAD column reactors. This model may be used for estimating the effluent nitrate–nitrogen concentration when the influent nitrate–nitrogen concentration ranges between 20 and 110?mg/L and the HRT ranges between 2 and 9?h. Based on our model and the requirement for nitrite control, we recommend that the HRT of the SLAD column reactor be kept ≥ 6?h and the nitrate loading rate less than 200 g NO3?–N/day?m3 media to achieve high nitrate removal efficiency (>99%) and prevent nitrite accumulation from being >1?mg/L NO2?–N.     

Comparison of Pollutant Removal Efficiency for Two Residential Storm Water Basins

Detention basins with a low-flow concrete channel or a vegetated channel are two types of storm water collection basins examined in this study to assess effectiveness in water quality improvement. Influent and effluent data collected from four storm events include flow, petroleum hydrocarbons, nutrients, total suspended solids, three major ions, and indicator organisms. The calculation of influent and effluent mass loading for each basin determines the removal efficiency, which is used to rank the more effective basin for water quality improvement. As expected, the detention basin with a low-flow concrete channel was found to be ineffective for improving the water quality of storm water. The vegetated detention basin was also found essentially ineffective for water quality improvement for all four storms, with low influent mass loading and flushing of stored water the most probable reasons for this result.