Development of Dissolved Oxygen Model for a Highly Variable Flow River: A Case Study of Ravi River in Pakistan

A framework for dissolved oxygen (DO) modeling of the Ravi River has been developed based on a combination of laboratory measurements and field and monitoring data. Both the classical Streeter-Phelps (CSP) and the modified Streeter-Phelps (MSP) models are used for DO simulations. The MSP model considers the carbonaceous biochemical oxygen demand (CBOD) and nitrogenous biochemical oxygen demand (NBOD) separately, whereas the CSP model is evaluated considering only the CBOD and NBOD is incorporated in the overall BOD utilization rate. CBOD, NBOD and BOD rates have been determined through long-term BOD analysis of five main wastewater outfalls and two surface drains discharging into the Ravi River over a 98 km stretch. Analysis by Thomas Method manifests strong coefficient of determination “R²” between 0.72 and 0.98 for all the three types of BOD rates. Sensitivity analyses have also been carried out to find out a suitable reaeration rate formula for highly variable flows in the Ravi River. The CSP model results based on classical approach of considering only CBOD show significant difference between the model predictions and field measurements suggesting that NBOD needs to be incorporated for the model development. The dissolved oxygen values calculated using the MSP model and the CSP model based on overall BOD rate are in close agreement with field measurements and are thus suitable to model DO levels in the Ravi River.     

Application of Water Quality Indices and Dissolved Oxygen as Indicators for River Water Classification and Urban Impact Assessment

The usefulness of water quality indices, as the indicators of water pollution, for assessment of spatial-temporal changes and classification of river water qualities was verified. Four water quality indices were investigated: WQI (considering 18 water quality parameters), WQI(min) and WQI(m) (considering five water quality parameters: temperature, pH, DO, EC and TSS) and WQI(DO) (considering a single parameter, DO). The water quality indices WQI(min), WQI(m) and WQI(DO) could be of particular interest for the developing countries because of the minimum analytical cost involved. As a case study, water quality indices were used to evaluate spatial and temporal changes of the water quality in the Bagmati river basin (Nepal) for the study period 1999-2003. The results allowed us to determine the serious negative effects of the city urban activity on the river water quality. In the studied section of the river, the water quality index (WQI) was 71 units (classified as good) at the entry station and 47.6 units (classified as bad) at the outlet station. For the studied period, a significant decrease in water quality (mean WQI decrease = 11.6%, p = 0.042) was observed in the rural areas. A comparative analysis revealed that the urban water quality was significantly bad as compared with rural. The analysis enabled to classify the water quality stations into three groups: good water quality, medium water quality and bad water quality. WQI(min) resulted in overestimation of the water quality but with similar trend as with WQI and is useful for the periodic routine monitoring program. The correlation of WQI with WQI(min) and DO resulted two new indices WQI(m) and WQI(DO), respectively. The classification of waters based on WQI(m) and WQI(DO) coincided in 90 and 93% of the samples, respectively.     

A Review of Public Domain Water Quality Models for Simulating Dissolved Oxygen in Rivers and Streams

The review discusses six major public domain water quality models currently available for rivers and streams. These major models, which differ greatly in terms of processes they represent, data inputs requirements, assumptions, modeling capability, their strengths and weaknesses, could yield useful results if appropriately selected for the desired purposes. The public domain models, which are most suitable for simulating dissolved oxygen along rivers and streams, chosen in this review are simulation catchment (SIMCAT), temporal overall model for catchments (TOMCAT), QUAL2Kw, QUAL2EU, water quality analysis simulation program (WASP7), and quality simulation along rivers (QUASAR). Each of these models is described based on a consistent set of criteria-conceptualization, processes, input data, model capability, limitations, model strengths, and its application. The results revealed that SIMCAT and TOMCAT are over-simplistic but useful to quickly assess impact of point sources. The QUAL2Kw has provision for conversion of algal death to carbonaceous biochemical oxygen demand (CBOD) and thus more appropriate than QUAL2EU, where macrophytes play an important interaction. The extensive requirement of data in WASP7 and QUASAR is difficult to justify the time and costs required to set up these complex models. Thus, a single model could not serve all wide range of functionalities required. The choice of a model depends upon availability of time, financial cost and a specific application. This review may help to choose appropriate model for a particular water quality problem.     

Determination of heavy metals in fresh water fish species of the River Ravi, Pakistan compared to farmed fish varieties

The untreated industrial and sewage wastes arising from industries and metropolitan activities make their passage to the River Ravi, Pakistan, where Balloki Headworks is one of the major sites of effluent concentration. This study was designed to evaluate the concentration of various toxic elements in fishes of that area compared to a nearby fish farm. The concentrations of heavy metals, such as As, Cd, Cu, Pb, Hg, and Zn, and electrolytes Ca, K, and Na were determined in different edible and non-edible fresh water fish varieties. Fish samples were collected from two selected sites and were analyzed for aforementioned elements. Higher levels of As (35.74–45.33 ppm), Cd (0.35–0.45 ppm), Pb (2.1–3.0 ppm), Hg (83.03–92.35 ppm) while normal levels of Zn (37.85–40.74 ppm) and Cu (1.39–2.93 ppm) were observed. Mercury, higher levels of which trigger cough, impairment of pulmonary function, and psychotic reactions, was significantly higher in all studied categories. At the sites under study, there has been observed alarming levels of toxic metals which are needed to be monitored regularly.     

示波极谱滴定法测定水和废水中的溶解氧

在pH值为6.5的NaAc-HAc底液中，加入经处理后的水样10ml，用EDTA标准溶液滴定其中的Mn^2 ，以EDTA在示波极谱上的切口到一定深度指示终点，废水的色度、浊度等对测定不产生干扰，不需进行预处理，操作简便、快速。该方法的相对误差小于1.0%，变异系数小于0.7%。     

花溪区思雅河水质分析与评价

在花溪区思雅河大学城段布设10个采样点,监测pH值、温度(T)、悬浮物(SS)、化学需氧量(COD)、氨氮(NH_3-N)、总磷(TP)和细菌总数(TPC)等指标,并采用单因子指数法、综合指数法和模糊综合法3种方法对水质进行评价。结果表明:河流主要污染指标为COD,且增势最明显,TPC和NH_3-N测定值的RSD均超过1,比其他指标变异程度更大;COD和TPC春冬季测定值高于夏秋季,NH_3-N测定值秋季最低,TP季节变化不明显,而冬季测定值较其他季节更稳定;思雅河大学城段水质较差,上游水质等级为Ⅳ类,中下游为劣Ⅴ类,主要污染源自农业和高校生活用水;3种方法中,模糊综合法更适用于小流域河流水质的定性定量评价,评价结果更加科学合理。     

基于水生态环境质量综合指数评价徐州河流

采用水生态环境质量综合指数对徐州市11个国控河流断面水环境质量进行评价。结果表明,各断面处于轻度污染到优秀级别,徐州市河流水生态质量整体良好。Spearman相关性分析显示各分指数中,水化学指标赋值与大型底栖动物赋值显著相关,着生藻类赋值与生境指标赋值负相关。指出,水生态环境综合评价指数弥补了单纯化学指标或单纯生物指标评价水质不够全面的问题,首次加入生境指标,体现了环境管理从指标控制到生态保护思路的转变。提出,对于水生态环境综合评价指数分指数化学因子、生物因子的评价指数如何选取,还需进一步完善。     

重铬酸钾─三氯化钛法测定水中溶解氧

介绍了三氯化钛（ＴｉＣｌ３）与氧反应，以钨酸钠（Ｎａ２ＷＯ４）作指示剂，用重铬酸钾溶液滴定过剩三氯化钛来测定水中溶解氧的方法。本法与碘量法比较，结果表明方法准确、快速，适合于水样中溶解氧的测定     

不同水质评价方法在漕桥河的应用与分析

选择单因子指数法、综合指数评价法及模糊综合评价法对漕桥河2008年—2011年的水质进行评价,并结合评价结果对3种评价方法进行分析比较。结果表明,采用模糊综合评价方法可以正确、全面地反映漕桥河的水质状况。     

Comprehensive River Water Quality Management by Simulation and Optimization Models

In this paper, the performance of water quality modeling is investigated in the analysis of the natural assimilative capacity (NAC) of a river system. The new data available, along with the appropriate integrated model, allow for the analysis of the NAC of the entire river. The integrated model developed here emphasized the implementation of the QUAL2E simulation model and the appropriate allocation of waste loads (optimization model) in a subtropical area. Simulations are calibrated and validated according to the data from the Water Quality and Flow Rate Monitoring Project using the QUAL2E model. On the basis of the optimal allocation model, the results of the NAC and allowable pollution loading in the Putzu River basin are discussed. The study provides a framework of the integrated model that can be used as a guideline to determine the NAC of subtropical rivers.     

南京市地表水溶解氧分布特征及低氧成因初探——以外秦淮河七桥瓮为例

于2018—2021年对南京市及国考断面七桥瓮进行水质调查,分析其溶解氧变化特征,采用水质水量联合评价及皮尔逊相关分析法,并结合水文气象等相关信息,对南京市地表水溶解氧分布特征及国考七桥瓮断面低氧成因进行研究分析。结果表明,南京市地表水溶解氧浓度夏季最低,中心主城区及附近区域溶解氧浓度均相对较低。七桥瓮断面溶解氧浓度在2.25~11.07 mg/L,其中5—9月溶解氧易出现超标波动。溶解氧浓度昼间高于夜间,与pH值呈正相关关系,与水温、高锰酸盐指数、氨氮、总磷均呈负相关关系。水温和上游来水带入的耗氧污染物是七桥瓮断面溶解氧偏低的主要成因,其中,溶解氧浓度与水温相关性最为显著。研究结论可为七桥瓮断面稳定达标提供基础支撑,为秦淮河流域精准治污提供技术依据,为南京市水环境多源同治提供治理思路。     

温榆河底栖大型无脊椎动物与水质评价

2006年10月对北京市温榆河12个采样点底栖大型无脊椎动物调查,并设立十三陵水库为对照点.结果表明,温榆河底栖大型无脊椎动物有三大类组成:水栖寡毛类、水生昆虫幼虫和软体动物等13种,水栖寡毛类中的颤蚓科种类和水生昆虫中的羽摇蚊幼虫为优势种,这些均为耐污种类,耐污染指数都在5以上,平均耐污值为8.底栖动物数量也很高,说明温榆河水体受有机污粢较为严重.通过1HB指数评价结果,认为对照点水质为一般水体,温榆河为污染水体到严重污染水体.     

浑太河流域水质达标控制方法研究

结合浑太河流域水资源网络节点图,根据污染物来源、种类及其产生机理,针对计算单元水资源供需平衡预测数据、降雨径流值,分点源、非点源进行规划水平年污染物入河量的预测。根据浑太河流域地形特征、入河污染物降解特性,以水功能区水体纳污能力为计算单元污染物排放总量控制条件,给出基于规划水平年入河污染物变动特性的水质达标控制方法。运用该方法进行浑太河流域水质达标控制:2030年,流域总需水7.4亿立方米,缺水深度在1%以下,COD、NH3-N、TP、TN的入河量分别为28.5×104、2.8×104、3.1×104、4.6×104t,对应的入河控制量分别为9.3×104、0.6×104、0.8×104、0.9×104t,经控制后水功能区目标水质达标率100%。证实了该水质达标控制方法有效、可行。     

袁河袁州区段溶解氧过饱和成因分析及防治

2020年8月15日袁河袁州区段(棚下-袁河水厂取水口)出现溶解氧过饱和现象,为了解该河段溶解氧的变化及提高河道流量前后对水生态环境的影响,将该段河道分为6个监测断面,于8月16—24日监测每个监测点的常规水质、浮游植物群落结构、溶解氧和实时流量.结果表明:自然状态下袁河袁州区段溶解氧沿水流方向从6.8 mg/L逐渐增...     

福建晋江水系浮游植物调查及水质状态的评价

2003年2~12月对福建晋江水系15个采样点的浮游植物群落季节性变动的生态特征,进行了种类组成、种群数量、优势种、污染指示种、水质等项目的调查研究。经鉴定晋江水系浮游植物共7个门类,73属,170种。藻量年均值达193.5×103个/升,晋江水系的浮游植物以硅藻门的种类占优势,表明晋江水系属于β_中污水体。并以这些参数对晋江水系的水质污染加以评价。     

北京市妫水河水质现状评价

2017年分3个时期(丰水期、平水期、枯水期)采集妫水河及其支流12个断面表层水样,分析了COD、氨氮、TP、DO、pH值等水质指标,采用单因子评价法、水污染指数法、主成分分析法和模糊综合评价法对水质进行评价,根据4种水质评价方法的评价结果,分析4种方法在小流域河流评价中的适用性。结果表明:目前妫水河12个断面中S2、S10和Z2 3个断面水质较差,基本属于地表Ⅴ类水,污染程度为重度污染;其他9个断面水质等级为地表Ⅳ类水,污染程度为中度污染;中段世园会段水质较好,优于上段和下段,主要污染指标为COD;妫水河主要污染源于农业和生活,枯水期水质优于平水期和丰水期。水污染指数法更适合小流域水体水质的定性定量评价,且计算方便简单。     

太浦河界标断面水质达标综合治理对策

简述了太浦河界标断面2020年水质考核目标以及区域水污染现状。指出,界标断面水质主要超标因子为DO和TP,农业面源污染、工业污染、生活污水处理相对滞后、内源污染、部分黑臭河道河段清淤不彻底是导致区域水污染的主要因素。提出,要推进农业面源污染治理,强化工业污染源治理,加强区域性污染物控制以及生活污染源整治,促进河湖生态系统恢复,加强自动监测站管理工作。     

岷江流域水质状况评价及变化趋势分析

通过岷江断面水质监测数据,利用内梅罗污染指数法进行水质评价,分析了2009—2013年岷江干流水质情况及其变化趋势。阐述了2013年岷江流域水质空间分布、月季变化情况。提出了流域水质污染防治建议。结果表明,岷江干流上游水质较好、中游较差、下游略有好转,体泉河等部分岷江支流水质较差。2013年全年来看,4—5月份水质较差,7—10月相对较好。     

南通濠河水体中非离子氨的动态变化分析

分析了濠河水体中非离子氨在不同断面、不同月份、不同年际的变化情况 ,并指出其超标的原因及控制措施     

深圳市河流水质评价指标筛选方案探讨

通过计算各条河流的综合污染指数和各项水质指标的污染分担率,对深圳市8条主要河流1999—2008年水质监测数据进行分析,最终从15项常规水质指标中筛选出氨氮、总磷、生化需氧量、化学需氧量、高锰酸盐指数、石油类、挥发酚、硫化物和六价铬9项指标,建议作为深圳市河流水质评价的统一指标。