Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary

Estuaries have been described as one of the most difficult environments on Earth. It is difficult to know how to treat the combined wastewater in tidal rivers at the estuary, where the situation is very different from ordinary fresh water rivers. Waste oyster shell was used as the active filler in this study in a bio-contact oxidation tank to treat the combined wastewater at the Fengtang Tidal River. With a middle-experimental scale of 360 ma/day, the average removal efficiency of COD, BOD, NH3-N, TP and TSS was 80.05%, 85.02%, 86.59%, 50.58% and 85.32%, respectively, in this bio-contact oxidation process. The living microbes in the biofilms on the waste oyster shell in this bio-contact oxidation tank, which were mainly composed of zoogloea, protozoa and micro-metazoa species, revealed that waste oyster shell as the filler was suitable material for combined wastewater degradation. This treatment method using waste oyster shell as active filler was then applied in a mangrove demonstration area for water quality improvement near the experiment area, with a treatment volume of 5 × 10^3 m^3/day. Another project was also successfully applied in a constructed wetland, with a wastewater treatment volume of 1 ×10^3 m^3/day. This technology is therefore feasible and can easily be applied on a larger scale,     

Formation of THMs and HANs during bromination of Microcystis aeruginosa

Bromine-contained disinfectants and biocides are widely used in swimming pools, recreational waters and cooling towers. The objective of this study was to evaluate the formation of thrihalomethanes (THMs) and haloacetonitriles (HANs) and their cytotoxicity in algae solutions during free bromine disinfection. Disinfection by-products formation potential experiments were conducted using model solutions containing 7 mg/L (as total organic carbon) Microcystis aeruginosa cells. Effects of free bromine dosage, pH and ammonia were investigated. The results showed that brominated disinfection by-products were the major products when free bromine was applied. The total THMs formed during bromination was much as that formed during chlorination, whereas HANs were elevated by using bromination instead of chlorination. Dibromoacetonitrice (C2H2NBr2 ) and bromoform (CHBr3 ) were the only detected species during free bromine disinfection. The production of C2H2NBr2 and CHBr 3 increased with disinfectant dosage but decreased with dosing ammonia. CHBr3 increased with the pH changing from 5 to 9. However, C2H2NBr2 achieved the highest production at neutral pH, which was due to a joint effect of variation in hydrolysis rate and free bromine reactivity. The hydrolysis of C2H2NBr2 was base-catalytic and nearly unaffected by disinfectant. Finally, estimation of cytotoxicity of the disinfected algae solutions showed that HANs formation was responsible for the majority of toxicity. Considering its highest toxicity among the measured disinfection by-products, the elevated C2H2NBr2 should be considered when using bromine-related algaecide.     

Eutrophication development and its key regulating factors in a water-supply reservoir in North China

Yanghe Reservoir is an important source of drinking water for Qinhuangdao City,North China;however,in recent decades this water source has been eutrophic with recurrent summer cyanobacterial blooms.The trophic grade of the system in summer was mesotrophiceutrophic in 1990 and became hypertrophic in 2011.The nutrient availability is extremely high during the entire year,and the water temperature should be the primary driver of the summer blooms.In May-October of 2010 and 2011,abrupt variations were observed in the Secchi depth(SD) and chlorophyll a(Chl-a),and both the correlated analysis of Chl-a-SD and trophic status indices(TSI) deviation(TSI Chl-a-TSI SD) showed that algal cell density dominated light attenuation.During the algal bloom outbreak,the microcystin concentration was found to vary between 0.35-2.12 μg/L in 2010 and 0.11-1.86 μg/L in 2011.The maximum microcystin content was more than two times the safety limit required for drinking water.Inflow discharges were most concentrated in the summer,with periods of lower residence time and the largest water level fluctuation over the entire year.When a high availability of nutrients promoted a high Chl-a concentration in the whole system,it appeared that the instability caused by the decrease in residence time could not produce effective changes in the cyanobacterial abundance.The results indicated that nutrient enrichment in the aquatic systems of Yanghe Reservoir is the most serious problem and that the status would not been modified effectively by increasing hydrological fluctuations(e.g.,decreasing the residence time).Therefore,decreasing the nutrient concentrations is the only route to improve the water quality of this reservoir.     

Speciation of organic phosphorus in a sediment profile of Lake Taihu II. Molecular species and their depth attenuation

The understanding of organic phosphorus(P) dynamics in sediments requires information on their species at the molecular level,but such information in sediment profiles is scarce.A sediment profile was selected from a large eutrophic lake,Lake Taihu(China),and organic P species in the sediments were detected using solution phosphorus-31 nuclear magnetic resonance spectroscopy(31 P NMR) following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA(NaOH-EDTA) solution.The results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate,orthophosphate monoesters,phospholipids,DNA,and pyrophosphate.Concentrations of the major organic P compound groups and pyrophosphate showed a decreasing trend with the increase of depth.Their half-life times varied from 3 to 27 years,following the order of orthophosphate monoesters > phospholipids DNA > pyrophosphate.Principal component analysis revealed that the detected organic P species had binding phases similar to those of humic acid-associated organic P(NaOH-NRP HA),a labile organic P pool that tends to transform to recalcitrant organic P pools as the early diagenetic processes proceed.This demonstrated that the depth attenuation of the organic P species could be partly attributed to their increasing immobilization by the sediment solids,while their degradation rates should be significantly lower than what were suggested in previous studies.     

关于加强我国污染场地环境管理政策建议探讨

本文在综述当前我国污染场地环境管理现状基础上,探讨了加强污染场地环境管理相关政策建议,以期为我国进一步完善污染场地环境管理提供决策参考。具体建议：强化污染场地信息管理;把握和贯彻基于风险的管理理念;搞好标准建设工作;重视复合绿色修复技术的研发;逐步开创适宜的融资机制和模式;建立合理有效的公众参与和信息公开制度。     

蔗渣垫料在零排放发酵床养猪中的应用研究

目前微生物发酵床养猪垫料是选用木屑、谷壳作为原料,来实现零排放养猪。文章选用农业固体废弃物——蔗渣为垫料应用于零排放漏缝发酵床养猪,跟踪了3个月垫料在实际使用中的温度、有机质、氮、磷、钾、微生物指标,对蔗渣的使用效果进行了评价,并建立PCR反应体系来扩增DNA,利用PCR-DGGE技术对垫料中的微生物群落多样性进行研究。结果表明:蔗渣作为垫料,能使垫床温度控制在40⁶5℃之间,保证了良好的发酵效果、且有效活菌数达到0.22×109cfu/g,可以对猪粪便等有机质进行较彻底的消解,因此蔗渣可以作为一种垫料应用于零排放漏缝发酵床;垫料中总养分达到1.371 7%,使用后的垫料可以作为一种原料生产生物有机肥。     

机场飞机起降循环污染物扩散分布研究

国际民航组织规定飞机的标准起降循环(LTO)为滑行、起飞、爬升和进近(不包括巡航阶段)4个阶段,而对机场污染产生影响的主要在起飞和降落阶段。为了计算的可行性,首先简化飞机在机场起飞降落的活动路线,分阶段计算出4个阶段对总的污染排放浓度的贡献;然后计算得出整个民航机场飞机起降循环过程的污染物扩散模型。基于此模型,用MATLAB软件对飞机在机场起飞降落过程中排放的NOx扩散分布进行仿真。     

温度和盐度对条纹环沟藻(Gyrodinium instriatum)生长的影响

在实验室条件下,研究了温度和盐度对条纹环沟藻(Gyrodinium instriatum)生长的影响。在28个温度(15～30℃)和盐度(0～35)组合中,条纹环沟藻在20℃和盐度25下生长最好。适宜生长温度为20～25℃,盐度为20～25。在适宜的盐度下,藻细胞对高/低温度的忍耐能力增强,同样适宜温度也可促进藻细胞对高/低盐度的抵抗能力。条纹环沟藻不能在无盐环境生长,但在适温下(20～25℃),能在盐度为10的条件下生长。研究结果说明条纹环沟藻是一种广盐生物,能适应较低的盐度,这也是其赤潮多在低盐的河口海域发生的重要原因。     

智能化海水重金属污染实时监测仪的研究

采用由白色光源发射的光束经透镜后变成平行光束,透过海水重金属污染而变色的化学试纸板反射后,照射在TCS230颜色传感器上,输出含不同色度系数的三基色电压信号,经单片机MSC1210对数据进行处理,在算法上运用改进型PB智能神经网络算法,从而提高对海水重金属污染的识别速度。利用GPRS无线传输网络技术和DAE技术,对数据无线传输和人机对话,实现了对海水重金属污染在线实时监测。实验证明,该智能化海水重金属污染实时监测仪法,虽在精度上没有分光光度法高,但它具有在线实时监测、识别速度快、仪器调整方便和适用范围广等优点。     

一株源自海洋环境多环芳烃降解菌的筛选、鉴定及适宜降解条件研究

利用以菲为唯一碳源的选择性富集培养基,从天津港6号码头潮间带表层沉积物中分离到1株多环芳烃降解细菌,命名为DHD,经16SrDNA序列比对结果显示,该菌株属门多萨假单胞菌(Pseudomonas mendocina)。DHD能以多种多环芳烃化合物包括萘、菲、蒽、芘为唯一碳源和能源生长。以菲为代表,通过摇瓶培养实验考察了该菌株降解多环芳烃的适宜培养条件为:酵母浸粉为氮源,初始pH 9.0,培养温度30℃,摇床转速为200 r/min。