Restoring water quality in the polluted Turag-Tongi-Balu river system, Dhaka: Modelling nutrient and total coliform intervention strategies

Abstract

River water quality in rapidly urbanising Asian cities threatens to damage the resource base on which human health, economic growth and poverty reduction all depend. Dhaka reflects the challenges and opportunities for balancing these dynamic and complex trade-offs which goals can be achieved through effective policy interventions. There is a serious problem of water pollution in central Dhaka, in the Turag-Tongi-Balu River system in Bangladesh with the river system being one of the most polluted in the world at the moment. A baseline survey of water chemistry and total coliforms has been undertaken and shows dissolved oxygen close to zero in the dry season, high organic loading together with extreme levels of Ammonium-N and total coliform in the water. Models have been applied to assess hydrochemical processes in the river and evaluate alternative strategies for policy and the management of the pollution issues. In particular models of flow, Nitrate-N, Ammonium-N and indicator bacteria (total coliforms) are applied to simulate water quality in the river system. Various scenarios are explored to clean up the river system, including flow augmentation and improved effluent treatment. The model results indicate that improved effluent treatment is likely to have a more significant impact on reducing Ammonium-N and total coliforms than flow augmentation, but a combined strategy would greatly reduce the pollution problems in the Turag-Tongi-Balu River System.

Integrative study of microbial community dynamics and water quality along The Apatlaco River

“…DO values follow the same trend found for COD; the worst levels of DO were found between P5 and P12 at around 3 mg/L. Low levels of DO can cause anoxic zones in the river and this stimulates microorganisms such as sulfate-reducing bacteria that release noxious gases such as hydrogen sulfide, or methanogenic bacteria that release methane gases; one of the most potent greenhouse gases [18].…”

Modeling the Impact of Extreme River Discharge on the Nutrient Dynamics and Dissolved Oxygen in Two Adjacent Estuaries (Portugal)

“…Numerical model calibration and validation processes are important steps when performing estuarine modeling studies. Given the complexity of these models and the frequent data limitations (e.g., lack of continuous in situ data), it is rare to find studies performing both processes simultaneously, as recognized by Whitehead et al [65] and Tomic et al [66]. By these reasons, a large number of modeling studies perform only one of these processes (e.g., [67][68][69][70]), or alternatively perform both processes for a very limited period or even solely based on seasonal data ( [71][72][73][74][75][76][77][78]).…”

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“…Total coliforms are a group of bacteria commonly found in aquatic environments produced from human fecal waste, animal feces and domestic waste (Messner et al, 2017;Whitehead et al, 2018;Frena et al, 2019). The nature of this bacterium has no taste, smell or color so laboratory analysis must be carried out and the result can be used as a microbiological indicator of a body of water measured in units of quantities mL (Divya and Solomon, 2016;Xue et al, 2018).…”