Remediation of Polluted River Water by Biological, Chemical, Ecological and Engineering Processes

Abstract

Selection of appropriate river water treatment methods is important for the restoration of river ecosystems. An in-depth review of different river water treatment technologies has been carried out in this study. Among the physical-engineering processes, aeration is an effective, sustainable and popular technique which increases microbial activity and degrades organic pollutants. Other engineering techniques (water diversion, mechanical algae removal, hydraulic structures and dredging) are effective as well, but they are cost intensive and detrimental to river ecosystems. Riverbank filtration is a natural, slow and self-sustainable process which does not pose any adverse effects. Chemical treatments are criticised for their short-term solution, high cost and potential for secondary pollution. Ecological engineering-based techniques are preferable due to their high economic, environmental and ecological benefits, their ease of maintenance and the fact that they are free from secondary pollution. Constructed wetlands, microbial dosing, ecological floating beds and biofilms technologies are the most widely applicable ecological techniques, although some variabilities are observed in their performances. Constructed wetlands perform well under low hydraulic and pollutant loads. Sequential constructed wetland floating bed systems can overcome this limitation. Ecological floating beds are highly recommended for their low cost, high effectiveness and optimum plant growth facilities.

Function-Oriented Graphene Quantum Dots Probe for Single Cell in situ Sorting of Active Microorganisms in Environmental Samples

“…These results indicate that the microbial community is affected by environmental substrates and environmental pollution levels ( Kong et al, 2019 ). Because of aeration and SMFC operation, the environmental samples are repaired to a certain extent ( Anawar and Chowdhury, 2020 ; Khan et al, 2021 ). Specialization of the community occurs through the emergence and selection of the most adapted phylotypes, which can be dye-tolerant or decolorizing species ( Yu et al, 2015 ).…”

The Sustainable Treatment Effect of Constructed Wetland for the Aquaculture Effluents from Blunt Snout Bream (Megalobrama amblycephala) Farm

“…Furthermore, aquaculture effluent has become a serious public concern, because it is rich in solid matter, organics, and dissolved metabolites, which may cause eutrophication, silting, oxygen depletion, ammonia and sulfide toxicity in the aquatic environment [4]. The untreated effluent is likely discharged into rivers or lakes, affecting the quality of water source for drinking [5]. Thus, the remediation of effluent is required in aquaculture farms to ensure environmental responsibility and sustainability.…”

Impact of industrial effluents on physico-chemical parameters of water and fatty acid profile of fish, Labeo rohita (Hamilton), collected from the Ramsar sites of Punjab, India

“…The industrial wastes generally contains high quantities of dissolved and suspended solids, heavy metals, organic and inorganic chemicals, high BOD and COD, oils and grease, besides toxic metals which cause deleterious effects on the fish when discharged in to water bodies. In India, 50% of human waste is discharged into water bodies, and majority of wetlands have been exploited for their natural cleansing capacity for assimilating various pollutants including heavy metals and pesticides (Joyce 2012 ; Anawar and Chowdhury 2020 ). Wetland plants and sediments accumulate various contaminants that enter the water through natural and anthropogenic activities which accumulated in fish tissues via the food chain; therefore, water, aquatic plants and fishes have been frequently used to assess wetland pollution all over the world and have been well grounded to be the biomarker of pollution load in water bodies (Kamal et al 2004 ; Li et al 2006 ; Adekola and Eletta 2007 ; Lu et al 2011 ; Souza et al 2013 ).…”