Environmental Engineering
R.G. Sarmurzina; G.I. Boiko; B.K. Kenzhaliyev; U.S. Karabalin; N.P. Lyubchenko; P.V. Kenyaikin; Zh.B. Ilmaliyev
Abstract
BACKGROUND AND OBJECTIVES: The reduction of fresh water deficit and water-related morbidity is the most important problem of the state’s national security. The effective treatment of natural water in industrialized areas from natural and anthropogenic pollutants is the main ecological task. Coagulation ...
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BACKGROUND AND OBJECTIVES: The reduction of fresh water deficit and water-related morbidity is the most important problem of the state’s national security. The effective treatment of natural water in industrialized areas from natural and anthropogenic pollutants is the main ecological task. Coagulation is one of the effective methods used to treat water chemically to purify it. Aluminum polyoxychlorides have gained popularity because of their advantages over coagulants—aluminum and iron sulfates. No production of aluminum polyoxychloride occurs in Kazakhstan despite the need for coagulants (the minimum need is assessed at about 11 thousand tons). The work is aimed at theoretical justification and experimental proof of a principally new approach to the development of aluminum polyoxychloride production technology based on activated aluminum alloys containing metal activators, such as gallium, indium , and tin from 0.5 to 5 percent weight. In addition, the goal is solving environmental issues associated with improving the drinking water quality and related to environmental pollution with wastewater.METHODS: The microstructures, phase components, and elemental compositions of alloys and reaction products were studied by scanning electron microscopy/energy dispersive X-ray spectroscopy. The thermal effects of alloys were investigated usin thermogravimetry methods. Oil content in wastewater was determined by spectrophotometry. Oil particle dimensions and wastewater zero potentials were determined using electrophoretic light scattering method and residual turbidity by turbidimetry. Water quality assessment was included in the purified water analysis and comparison with the sanitary and epidemiological standards established for drinking water supply and wastewater intended for water discharge.FINDINGS: The structures and compositions of activated aluminum alloy containing metal activators - gallium, indium, and tin - from 0.5 to 5 weight percent and aluminum polyoxychlorides based on it were studied using modern instrumental methods. The efficiency of the treatment of natural and oil-contaminated wastewater with aluminum polyoxychloride was assessed. The treated water parameters were within the norms established for drinking water supply and wastewater disposal by Sanitary Rules and Norms 2.1.4.559-96. The efficiency of potable water treatment reached 90–99 percent.CONCLUSION: An effective and technologically simple method is developed for producing aluminum polyoxychloride. It involves dissolving an activated alloy in 1–5 percent hydrochloric acid, with an aluminum content of 98.5–85 percent. Alloy processing is carried out at temperatures ranging from 60 to 65 degree celsius. The temperature rises from 20 to 25 degree celsius to the specified optimum without heat supply from the outside due to the interaction among reagents. The process is completed in 2–3 hours. The results confirm that aluminum polyoxychloride is an effective coagulant for drinking and wastewater treatment. The treated water is within the established limits in terms of hydrogen potential, chemical oxygen demand, and turbidity. The water treatment method can be easily implemented.
Environmental Engineering
A.M. Vazquez; A. Samudio-Oggero; H.D. Nakayama; I. Cantero-García
Abstract
BACKGROUND AND OBJECTIVES: The Municipal Park of Areguais is located in the Central Department of Paraguay. Part of this Park is within the area of influence of Ypakarai Lake, which is widely recognized by vacationersfor its natural spaces. Despite being one of the most representative ecological reserves ...
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BACKGROUND AND OBJECTIVES: The Municipal Park of Areguais is located in the Central Department of Paraguay. Part of this Park is within the area of influence of Ypakarai Lake, which is widely recognized by vacationersfor its natural spaces. Despite being one of the most representative ecological reserves in the country, annual waterquality reports indicate the presence of a high content of pollutants; mainly nitrogen, phosphorus, andfecalcolifoirs, among others. These conditions promote the proliferation of cyanobacteria which consume the available oxygenand compromise the reserve’s flora and fauna. Following several laboratory tests, the present work has the objective of evaluating the impact of thepark’s recently constructed wetland’son the treatment of residual waters.There are several parameters evaluated in thisstudy of final wastewater discharge disposal treatmentthrough a constructed wetland of horizontal flow with Typhadomingensis. The objective is to develop an adequate system for the treatment of residual waters that can be replicated in places with similar conditions.METHODS: The evaluation consisted of analyzing the residual water and finding the removal percentage for each of the following parameters such as chemical oxygen demand; biochemical oxygen demand; total phosphorus; total nitrogen; fecal coliforms; hydrogen potential; and temperature. The quality of the treated water was determined by comparing it with the limits established in Article 7 of Resolution Number 222/02 of the Environment Secretary for effluents. The results demonstrate that this system is aviableoption for the removal of fecal coliforms and nutrients such as phosphorus and nitrogen.FINDINGS: In terms of the quality of the treated water, the parameters studied are within the limits,established by Resolution Number 222/02of the Environment Secretary for Class 2 waters, for water to be discharged into the receiving body. The results obtainedwere: 88.9 percent fecal coliform removal; 84.9 percent total nitrogen; 73.3 percentchemical oxygen demand; 61.4 percent biochemical oxygen demand; and 14.2 percent Total Phosphorus. Considering Resolution 222/02, the biochemical oxygen demand, Total Nitrogen, and Total Phosphorus were outside the admissible limits.CONCLUSION: It is very feasible for wastewater generated in public parks to be treated through the construction of sub-surface flowwetlands.This study confirms that the treated wastewater is within the establishedlimitsfor all the parameters: temperature, hydrogen potential, biochemical oxygen demand, chemical oxygen demand, total nitrogen, total phosphorus, and fecal coliforms. This model of water treatment can be easily adopted.
Environmental Engineering
S. Nimesha; C. Hewawasam; D. J. Jayasanka; Y. Murakami; N. Araki; N. Maharjan
Abstract
Natural waterways are contaminated due to industrialization, urbanization, population growth etc., degrading their quality. Contaminated waterways cause numerous health and environmental hazards. Therefore, it is imperative to remove contaminants. Coagulation is one of the efficient primary chemical ...
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Natural waterways are contaminated due to industrialization, urbanization, population growth etc., degrading their quality. Contaminated waterways cause numerous health and environmental hazards. Therefore, it is imperative to remove contaminants. Coagulation is one of the efficient primary chemical treatment methods that could be used to treat such contaminants. Natural coagulants have gained popularity in the water and wastewater treatment industry due to their advantage over chemical coagulants. Natural coagulants are derived from either plants, animals, or microorganisms. This study has elaborated on the nature and mechanisms, and types of natural coagulants. In this review work, many studies have proposed several types of natural coagulants. However, plant-based natural coagulants extracted from different plant components have been extensively discussed and compared based on their application and efficiency in water and waste treatment. The primary purpose of this review is to refine the knowledge on the potential use and optimization of the effectiveness of eco-friendly and sustainable natural coagulants. Besides, the development efforts and the barriers reported by recent findings for the commercialization of natural coagulants are also discussed. Further, few modified natural coagulants have also been presented for exploring the other possible approaches to promote their usage in water and wastewater treatment in the future studies.
Environmental Engineering
S. Gautam; G. Saini
Abstract
Industrial effluents are a menace to the environment and the fact that their characteristics vary from industry-to-industry only adds to the complex challenge they offer to the engineers and scientists. Resource-efficient and environment-friendly solutions to this hazard are a call of the hour. Coagulation, ...
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Industrial effluents are a menace to the environment and the fact that their characteristics vary from industry-to-industry only adds to the complex challenge they offer to the engineers and scientists. Resource-efficient and environment-friendly solutions to this hazard are a call of the hour. Coagulation, by synthetic chemicals, has been used as a cost-effective and efficient method for managing the effluents generated by a large number of industries. However, the synthetic chemicals themselves are a cause of concern due to their non-native nature, non-degradability, and health conditions associated with their left-over residues. Natural coagulants offer a cost-effective, environment-friendly, and sustainable alternative to the application of synthetic chemicals. Such natural coagulants, despite their demonstrated effectiveness in treating the industrial wastewaters, have their own limitations and are yet to be investigated for large-scale applications. The current work presents a state-of-the-art review of the natural coagulants' application in treating industrial wastewaters and their relative advantages and disadvantages as compared to the chemical coagulants. Future research areas have also been identified that may ultimately lead to the large-scale commercial application of natural coagulants and will result in an environment-friendly and sustainable solution to the problems created by industrial effluents and synthetic chemical coagulants.
