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

2020 ◽  
Vol 12 (17) ◽  
pp. 7017
Author(s):  
Hossain Md Anawar ◽  
Rezaul Chowdhury

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.

Author(s):  
Victor Odhiambo Shikuku ◽  
Wilfrida N. Nyairo

The search for efficient and sustainable wastewater treatment technologies is a subject of continuing research. This is due to the emergence of new classes of water contaminants that are recalcitrant to the conventional wastewater treatment technologies and the stringent allowable limits for contaminant levels set by environmental management authorities. The chapter discusses the developments in synthesis methods and application of polymer-metal oxides as emerging facile materials for wastewater treatment. The varying uses of polymer-metal oxides for different processes in water treatment under varying operational conditions and their performance for different pollutants are critically analyzed. Their strengths and inherent limitations are also highlighted. The chapter demonstrates that polymer-metal oxides are facile low-cost and efficient materials and can be integrated in wastewater and drinking water treatment systems.


2013 ◽  
Vol 726-731 ◽  
pp. 1764-1769
Author(s):  
Qing Feng Chen ◽  
Hong Yan Yang ◽  
Jun Jian Ma ◽  
Wen Guo Dong ◽  
Meng Liu

The traditional water treatment technologies mainly include physical reparation technology, chemical remediation technology and biological-ecological restoration technology. However, there are many limitations in practical application, especially for heavy polluted river. For this reason, it is extremely urgent to explore new technology and method on river ecosystem restoration. The materials of artificial plants are limited to the factors of water transparency, possesses acid and alkali-resistant, resistance to staining and flexibility. The characteristics of artificial plants are low in investment, effective and no secondary pollution. Therefore, it has a broad prospect of application in water treatment. In this paper, the detailed review and application of artificial plants were involved in order to provide theoretical basis for more widely used of artificial aquatic plants.


2020 ◽  
Vol 103 (4) ◽  
pp. 1405-1415 ◽  
Author(s):  
Courtney L. Hill ◽  
Kelly McCain ◽  
Mzwakhe E. Nyathi ◽  
Joshua N. Edokpayi ◽  
David M. Kahler ◽  
...  

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 690c-690
Author(s):  
R.D. Berghage

Constructed wetland biofilters have been widely used in recent years to provide secondary or tertiary water treatment, effectively reducing BOD, TSS, nitrate and ammonium, and some organic pollutants from municipal, industrial, and agricultural waste sources. The greenhouse and nursery industries, like all agricultural enterprises, have found themselves under increasing pressure to reduce or eliminate discharge of contaminated wastewater. In response, many greenhouse and nursery operators have installed, and are using, a variety of runoff containment and recirculating irrigation systems. While effective in reducing or eliminating wastewater discharge, these systems can become contaminated themselves and require treatment of the water before it can be reused in the irrigation system. Further, if the water should become contaminated and unusable, environmental discharge of this spent water from a recirculating irrigation system is perhaps even more problematic than simply allowing the excess irrigation water to be dumped in the first place. Potential contaminants in a recirculating irrigation system could include pesticide and other organic residues, excess fertilizer and non-fertilizer salts, and plant pathogens. The primary concern in greenhouse and nursery discharge wastewater is usually fertilizer salts, although pesticide and other organic chemical residues may also be of concern. Biological filtration using constructed wetlands may be a simple low-cost method for greenhouses and nurseries to treat these contaminants.


Author(s):  
Victor Odhiambo Shikuku ◽  
Wilfrida N. Nyairo

The search for efficient and sustainable wastewater treatment technologies is a subject of continuing research. This is due to the emergence of new classes of water contaminants that are recalcitrant to the conventional wastewater treatment technologies and the stringent allowable limits for contaminant levels set by environmental management authorities. The chapter discusses the developments in synthesis methods and application of polymer-metal oxides as emerging facile materials for wastewater treatment. The varying uses of polymer-metal oxides for different processes in water treatment under varying operational conditions and their performance for different pollutants are critically analyzed. Their strengths and inherent limitations are also highlighted. The chapter demonstrates that polymer-metal oxides are facile low-cost and efficient materials and can be integrated in wastewater and drinking water treatment systems.


Author(s):  
Gonzalo Flores-Morales ◽  
Mónica Díaz ◽  
Patricia Arancibia-Avila ◽  
Michelle Muñoz-Carrasco ◽  
Pamela Jara-Zapata ◽  
...  

Abstract A feasibility analysis of tertiary treatment for Organic Liquid Agricultural Waste is presented using filamentous algae belonging to the genus Cladophora sp. as an alternative to chemical tertiary treatment. The main advantages of tertiary treatments that use biological systems are the low cost investment and the minimal dependence on environmental variables. In this work we demonstrate that filamentous algae reduces the nutrient load of nitrate (circa 75%) and phosphate (circa 86%) from the organic waste effluents coming from dairy farms after nine days of culture, with the added advantage being that after the treatment period, algae removal can be achieved by simple procedures. Currently, the organic wastewater is discarded into fields and local streams. However, the algae can acquire value as a by-product since it has various uses as compost, cellulose, and biogas. A disadvantage of this system is that clean water must be used to achieve enough water transparency to allow algae growth. Even so, the nutrient reduction system of the organic effluents proposed is friendly to the ecosystem, compared to tertiary treatments that use chemicals to precipitate and collect nutrients such as nitrates and phosphates.


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