ΔDO单一指标评价景观水体富营养化的研究

提出了采用水中溶解氧昼夜浓度最大差值(ΔDO)单一指标来及时评价景观水体富营养化程度的方法。在光暗比为1∶1、温度为25℃、光照强度为2 000 lx条件下,通过测定不同纯藻的光合产氧速率和叶绿素a(Chl-a)浓度,以及实际混合藻群的DO、ΔDO和Chl-a浓度,建立了不同藻种及混合藻群ΔDO与Chl-a浓度的关系,探讨了采用ΔDO单因素评价景观水体富营养化程度的可能性。结果表明,在含铜绿微囊藻、小球藻、伪鱼腥藻、混合藻群的实际景观水体中,ΔDO与Chl-a浓度的Pearson相关系数分别为0. 95、0. 96、0. 97和0. 93,相关性显著。因此,采用ΔDO作为富营养化程度单因素评价指标有一定的可行性。此外,还确定了不同ΔDO对应的水体富营养化程度范围,可为景观水体富营养化程度评价提供有效、快捷的方法。     

环境因子对湖泊底泥释磷的影响研究

在实验室模拟条件下考察了上覆水的TP浓度、pH、温度、溶解氧(DO)浓度、光照、水体扰动等因素对湖泊底泥释磷的影响.结果表明:上覆水为蒸馏水时底泥的释磷强度高于上覆水为真实湖水时的,底泥释磷强度受控于水体中磷酸盐的饱和度;光照对底泥释磷影响不明显,但温度和DO浓度对底泥释磷均有一定影响,升高温度或提高DO浓度均可促进底泥释磷;上覆水的pH呈中性时底泥的释磷强度最小,碱性条件下底泥的释磷强度高于酸性条件下的;扰动可明显提高底泥的释磷强度和速度.     

再生水回用改善河道水质的研究

以同心河为研究对象,考察了再生水引入后对河道水质的改善效果。结果表明,再生水引入后,同心河水体的DO浓度明显提高并长期稳定在3 mg/L左右,浊度大都降至10 NTU以下,COD浓度由150~250 mg/L下降到50 mg/L左右,氨氮和总磷浓度分别削减了(50%~94%)、(40%~89%),总磷浓度大多控制在0.5 mg/L以下,同心河水体水质改善显著。     

深圳河水体污染特征分析及整治措施

为提高深圳河的水环境,在水体污染特征分析及污染源解析的基础上,对污染物削减目标进行了估算,并提出了最大日负荷总量(TMDL)水质改善措施。结果表明,水体中DO浓度较低,71%的断面水体中氨氮和总氮浓度超出地表Ⅴ类水质标准,且氨氮和总氮浓度均沿河流方向升高。各行政区中生活和工业废水及河道底泥是水体污染的主要来源,福田区污染贡献占比最大,生活污水排放占比为33%,工业废水排放对河道COD、氨氮的贡献率分别达到42%、44%,是溯源截污的重点区域。通过截污清淤、海绵调蓄、生态修复及景观营造等措施,可以实现2020年全面消黑及2025年水质达到Ⅴ类水的目标。     

小型泄水建筑物对城市内河污染的影响

通过对城市内河小型泄水建筑物--溢流堰上下水体中的DO,高锰酸盐指数,TN,TP的长期监测,分析比较发现:溢流堰可以显著增加水体DO、去除水中耗氧有机物、在一定程度上降低水体中的氮、磷含量,对城市内河水体能够起到一定的净化作用.     

单级自养脱氮系统运行周期内的DO变化研究

以人工配制的低C/N值废水为处理对象,考察了单级自养脱氮系统在一个反应周期内DO浓度的变化规律及其与含氮物质转化的相关性。结果表明,当DO分别控制在2.0和1.5mg/L时,对TN的去除率分别为69.7%和81.1%,在氨氮转化结束前,DO浓度基本保持不变,到氨氮转化结束时出现DO浓度突然升高的折点。不同DO浓度条件下的试验进一步验证了DO变化特征点的重现性,DO浓度变化特征点可作为判断氨氮转化完成从而可停止曝气的控制点。     

水体沉积物中石油污染物的生物降解试验研究

研究了高效石油降解茵(邻单胞菌属)对水体沉积物中石油污染物的处理效果,以及微生物接种量、石油烃初始浓度和上层水体中溶解氧浓度对其降解效果的影响.结果表明,微生物接种量越多,石油烃去除率越高,加入30 mL浓度为105CFU/mL的菌悬液时,沉积物中石油烃的去除率为34.94%;沉积物中石油烃初始浓度过高或过低均不利于石油烃降解,当试验土样中石油烃浓度为107.15 mg/kg时,石油烃的去除率为77.30%;水中溶解氧浓度的提高可以加速石油烃的降解,密闭曝气状态下水中DO为7.09 mg/L时,石油烃的去除率为64.95%.     

曝气生态浮床/PRB组合工艺净化重污染河水研究

通过中试考察了曝气生态浮床/可渗滤反应墙(EAFB-PRB)组合工艺对重污染河水的净化效果.结果表明:组合工艺对COD、TN、NH_4~+-N和TP都有较好的去除效果,平均去除率分别为79.5%、27.9%、36.8%和87.0%;经处理后,水体的平均DO浓度由0.09 mg/L提高到1.7mg/L;对TSS的平均去除率达95.4%,出水清澈透明,感官效果好.可见,该组合工艺是改善重污染河水水质的有效方法.     

DO对单级聚氨酯脱氮系统运行效果的影响

应用单级聚氨酯生物膜反应器处理实际生活污水,考察不同DO浓度下微生物群落结构与其处理效果的关系。经过160 d的稳定运行,在不同DO浓度下,聚氨酯生物膜系统内均发生了同步硝化反硝化。DO为0.5~1.0 mg/L时得到最大氮去除率(70.6%),其中的72.9%由同步硝化反硝化完成。通过分析氮浓度,亚硝酸盐氮的最大积累量发生在DO为0.5~1.0 mg/L时。对生物膜上功能微生物的分析表明,DO为1.5~2.5 mg/L时的微生物多样性要显著高于其他工况。PCR-DGGE分析结果表明,优势亚硝化菌和硝化菌分别以Nitrosomonas sp.和Nitrospira sp.为主,而反硝化菌则是Thauera sp.和Pseudomonas sp.占据优势。     

短程硝化曝气生物滤池效果分析与运行参数优化

为改善短程硝化曝气生物滤池(BAF)的运行效果,通过单因素试验确定了最佳温度、pH值和溶解氧(DO)浓度,并在此基础上采用响应面分析法中Box-Behnken中心组合设计进行了运行参数优化试验与回归模型分析。试验结果表明,短程硝化BAF最佳运行条件如下:温度为30℃、pH值为8. 5、DO为2. 0 mg/L;基于响应面分析法优化短程硝化BAF运行参数得到的最优模型如下:温度为28. 3℃、p H值为8. 1、DO为2. 15 mg/L,在此条件下对氨氮的去除率达到92. 15%,亚硝酸盐氮积累率为92. 65%。响应面试验回归模型的分析结果显示,该模型具有较高的显著性(P 0. 000 1),pH值和DO对氨氮去除率的影响显著,且交互作用明显;温度、pH值和DO对亚硝酸盐氮积累率的影响显著,且pH值和DO、温度和pH值交互作用明显。     

Analysis of photosynthetic activity in the most polluted stretch of river Ganga

As a result of the increasing anthropogenic activities in the gangetic plain, Ganga water quantity as well as quality has declined over the years. A major effort to clean Ganga, named Ganga Action Plan (GAP) was instituted by the Government of India in 1984. The emphasis in GAP was on the reduction of organic load on the river through interception, diversion and treatment of wastewater reaching the river, thus maintaining the biochemical oxygen demand (BOD) and dissolved oxygen (DO) levels of river within the acceptable limits. A major criticism of GAP is that the significance of river ecology has not been addressed adequately during its conception and implementation. One of the important aspects from this perspective is the photosynthetic activity in the river Ganga. It has been postulated that photosynthetic activity plays an important role in maintaining high levels of DO in Ganga, and as a result the river can assimilate high organic loads without appreciable depletion in dissolved oxygen levels. Objective of the present study was to assess the photosynthetic activity and oxygen production rates in the river and correlate these values with various water quality parameters. Most polluted stretch of Ganga, which is known as the Kannauj-Kanpur stretch was chosen for this study. Based on the results of the study, it was concluded that despite implementation of phase I of GAP, and consequent diversion and reduction of organic loading to the river, both BOD and DO levels in the river has increased in the entire Kannauj-Kanpur stretch, except at Jajmau, where anaerobically treated effluent is discharged to the river. The nitrogen levels have also increased in the entire Kannauj-Kanpur stretch. Dissolved oxygen (DO) and alkalinity in the river water vary diurnally at all sites. Chlorophyll-a levels and oxygen production rates due to photosynthesis appear to be positively influenced by phosphate levels in the river water. Chlorophyll-a levels appear to be negatively correlated to the Ammonical and total Total Kjeldahl Nitrogen (TKN) content in the river water, suggesting the possibility of release of nutrients due to algal death and decomposition under certain circumstances.     

再生水景观水体富营养化因素的垂直变化特征

合肥市环城水系是以再生水为唯一补水水源的城市景观水体,选择环城水系中具有代表性的银河水体,对河道水体中的磷、氛、溶解氧和pH值的垂直分布及变化规律进行了研究。结果表明,沿水体的深度方向,总磷、氨氮、正磷酸盐浓度逐渐增高,pH值和溶解氧浓度则逐渐降低。溶解氧和pH值可间接反映藻类的生长情况和密度,可作为水华暴发的简便预警指标。     

Using river distances in the space/time estimation of dissolved oxygen along two impaired river networks in New Jersey

Understanding surface water quality is a critical step towards protecting human health and ecological stability. Because of resource deficiencies and the large number of river miles needing assessment, there is a need for a methodology that can accurately depict river water quality where data do not exist. The objective of this research is to implement a methodology that incorporates a river metric into the space/time analysis of dissolved oxygen data for two impaired river basins. An efficient algorithm is developed to calculate river distances within the BMElib statistical package for space/time geostatistics. We find that using a river distance in a space/time context leads to an appreciable 10% reduction in the overall estimation error, and results in maps of DO that are more realistic than those obtained using a Euclidean distance. As a result river distance is used in the subsequent non-attainment assessment of DO for two impaired river basins in New Jersey.     

改进型Living Machine系统净化城市河水的研究

以净化城市受污染河水为目标,对Living Machine系统进行改进而构建了植物浮床生态箱/植物浮床生态箱/人工湿地/沉水植物生态箱系统,在系统中引入了多种植物以及鱼类、螺蛳、虾等物种,并以间歇方式运行,平均水力停留时间为2 d.结果表明,经过该系统处理后河水的DO含量提高了100%,对NH4--N的去除率为82.4%,对TN的去除率为23.4%,对TP的去除率为50.2%,对COD的去除率为28.1%;出水DO、NH4+-N、TN、TP、COD分别为5.20、0.42、9.78、0.34、12.72 mg/L.     

Causes of low oxygen in a lowland, regulated eutrophic river in Eastern England

In the River Brett, Eastern England, over the period 1955-1998 there was a significant long-term decline in dissolved oxygen (DO), as well as increases in TON (total oxidised nitrogen) and SRP (soluble reactive phosphorus). Flow decreased from 1963 to 1998. Field studies in 1998-2000 showed increased pH and a gradient of DO beneath the filamentous alga Cladophora glomerata. DO decreased through the summer. Macrophytes accounted for 45% of community respiration at the study site, while sediment accounted for 36%. In container studies, muddy sediments had the highest maximum sediment oxygen demand (SOD), but canopies of C. glomerata and Lemna minor together increased the SOD by up to 90% over control samples. During periods of high temperature, abundant growths of C. glomerata and/or L. minor would increase the SOD of organic mud in river areas with shallow, ponded water, eventually leading to anoxic conditions and the release of nutrients from the sediment. If a river had large areas of mud, these processes could dramatically affect the river's oxygen budget, and hence its ecology.     

南京城区某黑臭排涝水体综合整治

以南京市江宁区杨家圩河道为例,通过对河道周边排口、水质等状况进行调查,探讨河道水环境综合整治的方案设计及工程应用,并取得了一定的成果。结果表明,通过对该河道采取控源截污、集成式生物强化系统、多功能综合生态湿地、水下曝气复氧、生态组合修复以及环保清淤等综合整治措施,河道水质指标均有极大改善,溶解氧浓度从均值0.48 mg/L上升到均值3.04 mg/L,提升了5.96倍,而氨氮、总磷和COD分别平均降低了66.94%、78.73%和57.84%,基本达到《地表水环境质量标准》(GB 3838—2002)Ⅴ类标准。     

Accelerated reoxygenation of water bodies using hydrogen peroxide

This paper reports a laboratory study of an accelerated reoxygenation treatment of polluted water bodies, using hydrogen peroxide (H₂O₂): conditions such as the discharge of waters from domestic sewers or polluted storm-water resulting from intense rainfall that lead to a reduction in the level of dissolved oxygen (DO). We studied the water from rivers that make up the basin of the Lagoa Rodrigo de Freitas (LRF) lagoon, Rio de Janeiro, Brazil. When intense rainfall coincides with discharge from sewers, the polluted water may reach LRF. This has in the past led to episodes of critical deficit in DO in the waters of the lagoon, resulting in fish kill. To study this, we carried out experiments with water samples taken from the river feeding the lagoon. To study the accelerated reoxygenation of the river waters, we used different doses of H₂O₂. We concluded that the addition of H₂O₂ to the waters of the river during polluting events can prevent the level of DO in the lagoon going below a critical value. This treatment resulted in an immediate increase in DO that lasted hours and in the sustainability of the DO above the legal limit 5.0 mg L^?1, enough to avoid fish kill.     

Water quality and pollution loading of a river segment affected by landfill leachate and domestic waste

The Marikina River in the Philippines has been polluted by Payatas landfill leachate, and domestic and agricultural waste. This study monitored the water quality at five stations on the river and two stations on two creeks that discharge to the river to determine the effects of Payatas landfill and to estimate pollution loading. The dissolved oxygen (DO), chemical oxygen demand (COD) and other water quality parameters were compared with the Philippines Standards for river water classification. It was found that Payatas leachate has a significant influence on the DO and COD levels as well as other water quality parameters. Per capita pollution loading for Quezon City was found to be lower than for Europe and Japan. The effect of leachate is more significant during the dry season. It is recommended that a leachate collection system be established to prevent leachate form entering Payatas creek, and that the Patayas landfill be replaced with a modern landfill site, conforming to current best practice at another location.

List of Abbreviation: BOD= Biological Oxygen Demand COD = Chemical Oxygen Demand DO = Dissolved Oxygen EC = Electrical Conductivity M1, M2, M3, M4, M5 = monitoring stations TDS = Total Dissolved Solids TSS = Total Suspended Solids     

Stream productivity analysis with dorm—I: Development of computational model

A numerical dissolved oxygen routing model (DORM) is developed to determine total stream community photosynthesis (P) and community respiration rates (R) through iterative routing of two-station diel DO measurements. The model differs from existing procedures for diel curve productivity analysis; it uses the complete stream DO transport equation, including longitudinal dispersion, dependence of respiratory rate on water temperature and dissolved oxygen and wind dependent oxygen transfer through the water surface. The model, DORM, is more accurate than the traditional graphical procedures of diel curve analysis and is simple to apply. DORM is also valuable in an analysis of the results' sensitivity to the numerous coefficient and parametric assumptions required in diel curve analysis. The model is not a predictive DO model, but is designed for the interpretation of DO measurements in a stream, channel or river.