Influence of Biological Oxygen Demand Degradation Patterns on Water-Quality Modeling for Rivers Running through Urban Areas (original) (raw)
Related papers
Modeling Water Quality in Rivers
American Journal of Applied Sciences, 2005
This study reports a PC software, used in a Windows-based environment, which was developed based on the first order reaction of Biological Oxygen Demand (BOD) and a modified Streeter and Phelps equation, in order to simulate and determine the variations of Dissolved Oxygen (DO) and of the BOD along with the studied river reaches. The software considers many impacts of environmental factors, such as the different type of discharges (concentrated or punctual source, tributary contribution, distributed source), nitrogenous BOD, BOD sedimentation, photosynthetic production and benthic demand of oxygen, and so on. The software has been used to model the DO profile along one river, with the aim to improve the water quality through suitable engineering measure.
A Review of Public Domain Water Quality Models for Simulating Dissolved Oxygen in Rivers and Streams
Environmental Modeling & Assessment, 2011
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 (TOM-CAT), 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. Public Domain Water Quality Models 185 186 P.R. Kannel et al.
Modelling Dissolved Oxygen Depression in an Urban River in China
Water, 2017
Dissolved oxygen (DO) depression in urban rivers appears to be increasing in developing countries, which causes severe aquatic ecosystem stresses. One urban river which suffers DO depression under low flow conditions and requires systematic research for effective mitigation strategies is the Nanfei River (Hefei, China). We investigated its longitudinal profiles of DO and other related water constituents with high spatial resolution monitoring at low flow. A mechanistic DO model for the reach was customized and calibrated with the data obtained. We found that the daily average DO levels within the 11 km study reach shifted from supersaturation (11.5 mg L −1) upstream of the Wangtang Wastewater Treatment Plant (WWTP) to serious depletion (3.6 mg L −1) downstream. Process analysis indicated that DO production via strong algal photosynthesis overwhelmed the DO consumptions upstream from the WWTP. In contrast, DO sources could not compensate for DO consumptions, wherein carbonaceous deoxygenation was the largest consumer of the DO (approximately 70%) downstream the WWTP. Rather than directly contributing labile organics, the WWTP effluent affected the DO balance by shifting the metabolism from upstream autotrophy to downstream heterotrophy. Finally, mitigation strategies for DO depression in rivers in rapidly-urbanizing regions were suggested accordingly.
Water Quality Simulation and Dissolved Oxygen Change Scenarios in Lam Takhong River in Thailand
Journal of Sustainable Development of Energy, Water and Environment Systems, 2022
Dissolved oxygen (DO) in Lam Takhong River gradually reaches zero value during the dry season on several occasions in the past decade causing the unsuitable quality for use as the raw water for Nakhon Ratchasima Town. Discharges of point sources and diffuse sources containing pollutants with organics and nutrients are the major cause of water quality deterioration in the river. To find the sources of impact on the water quality in the river, a one-dimensional steady-flow systems river water quality model, QUAL2Kw, was constructed and simulated. The model was calibrated and validated using the water quality data from 2008 to 2017 for the Lam Takhong River by seven monitoring stations. The modelling was applied to simulate various water quality parameters during the critical period to compare to the designated surface water quality criteria third class in Thailand (minimum dissolved oxygen at or above 4 mg/L; maximum biochemical oxygen demand (BOD), nitrate-nitrogen, and ammonia-nitrogen at or below 2.0, 5.0 and 0.5 mg/L, respectively). The study reach of the river flows 122 km from Lam Takhong Dam to the Mun River at Chaloem Phra Kiat district through the urban central area. Several segments of the river have been alarmed for many constituents with the dissolved oxygen impairment is the focus of the study. The scenarios of loads and upstream dissolved oxygen modification were conducted to assess the change of dissolved oxygen concentration. The result of the QUAL2Kw model showed that the decomposition of organic matter and a poor reaeration were the primary cause of the impairment. The local oxygenation causes fluctuations in dissolved oxygen levels along the river and the dissolved oxygen concentration decreases downstream of the river with some values fell the meet the fourth class of surface water quality criteria in Thailand (DO above 2 mg/L and BOD 5 <4 mg/L). The QUAL2Kw model is suitable for simulating the current and future river water quality and help water resources managers to issue the appropriate policy options for the Lam Takhong River.
Journal of Applied Mathematics
Analyzing and improving mathematical models for water quality investigation are imperative for water quality issues around the world. This study is aimed at presenting the 1D unsteady state regarding analytical and numerical solutions of dissolved oxygen (DO) concentration in a river, in which the increase of pollution from a source is considered as an exponential term. Laplace transformation was utilized to obtain analytical solutions, while the finite difference technique was selected for numerical solutions. The results show that the rate of pollutant addition along the river (q) and the arbitrary constants of an exponentially increasing pollution source term (λ) affected inversely, while the initial concentration Xi affected directly, DO in the river. These solutions and simulations can be enabled for testing in various scenarios in terms of the behavior of oxygen depletion in polluted rivers.
River water quality management using mathematical modelling
1996
A mathematical model has been calibrated and run for a range of River Cavado flow conditions to predict river water quality changes after pollutant loads. Biochemical oxygen demand (BOD), dissolved oxygen (DO) and faecal coliforms (FC) bacteria were used as water quality control parameters to assess critical situations near the proposed site for the construction of a new water treatment plant for the portuguese metropolitan area of Oporto.
Ksce Journal of Civil Engineering, 2008
Biochemical Oxygen Demand (BOD) modeling in a river involves derivation and solution of the governing partial differential equation, which describes concentration change with time and space due to convection, dispersion, decay and the loading function. In this study, an analytical model is developed for BOD simulation for the boundary condition when the waste discharge concentration can be described a sinusoidal variation. The analytical model is obtained by solving the governing partial differential equation considering (i) the river for which BOD is uniformly distributed through any cross-section so that a one dimensional model is applicable and (ii) for specific initial and boundary conditions. The results of the model for BOD simulation validated for (i) water quality data from River Gomti in India, which is an important tributary of Ganga River with significant influx of pollutants, and (ii) the data sets used for validation of commonly used analytical models and are available in the published literature. The proposed model is found to represent the physical processes occurring in River Gomti with high correlation between observed and simulated BOD values. Moreover, the results obtained from other data sets published in the literature demonstrate the applicability of developed analytical model for BOD simulation.
2016
In this paper various mathematical models developed to date accounts for only that portion of BOD which is in dissolved form and not the least in settleable form. These models also do not account for the storage zone in a scattered way in rivers and hence do not represents the actual situation caused by the discharge of partially treated/ untreated waste water, which contains a significant portion of BOD in settleable form into the water body with a large width where the water becomes stagnant anywhere, due to rag/garbage in rivers. The present paper represents a model to predict the concentration of total BOD when partially treated/untreated waste water is discharged into the Damodar river having staggered storage zones and thus address the above stated situation.
Modeling biochemical oxygen demand in a river with scattered storage zones
Applied Mathematical Sciences
Mathematical models have often been accepted as a useful tool to assess and manage water quality in water bodies. Dissolved Oxygen (DO), a surrogate variable for the general health of an aquatic ecosystem and Biochemical Oxygen Demand (BOD) are two important parameters to assess the level of pollution in river/stream. Various models developed to date accounts for only that portion of BOD which is in dissolved form and not the least in settleable form. These models also do not account for the storage zone in a scattered way in rivers and hence do not represents the actual situation caused by the discharge of partially treated/ untreated waste water, which contains a significant portion of BOD in settleable form, into the water body with a large width where the water becomes stagnant anywhere, due to rag/garbage in rivers. The present work represents a model to predict the concentration of total BOD when partially treated/untreated waste water is discharged into the river having staggered storage zones and thus address the above stated situation.
Development of refined BOD and DO models for highly polluted Kali River in India
Journal of Environmental Engineering, 2007
Most commonly used river water quality models for biochemical oxygen demand ͑BOD͒ and dissolved oxygen ͑DO͒ simulations are mainly based on advection, decay, settling, and loading functions. Using these concepts, refined river water quality models for BOD and DO simulations are developed in the present work considering a large number of physically based parameters and input variables. The refined models developed can be transformed to some of the commonly used river water quality models, if physically based parameters and input variables are omitted or removed. To test the applicability of the refined models developed and commonly used models, a total of 732 water quality and flow data sets are collected during March 1999-February 2000 from 22 sampling stations of the River Kali in India. River Kali is a highly polluted river in India and receives continuous inflow of untreated point source pollution from municipal and industrial wastes and nonpoint source pollution from agricultural areas. Newton-Raphson technique is used to optimize the model parameters during calibration and the performance of different models are evaluated using error estimation, viz. standard error and mean multiplicative error, and correlation statistics ͑r 2 ͒. The results indicate that the BOD-DO models proposed by Camp in 1963 provide better results in comparison to other commonly used models. Moreover, the refined models developed for BOD and DO simulations minimize error estimates and improve correlation between observed and computed BOD and DO values of River Kali.