As a rule, nitrates are present in all natural water bodies. Their increased concentrations are connected with the discharge of insufficiently treated wastewater from industrial and communal enterprises, agricultural and livestock complexes. Recent scientific publications concerning treatment methods for nitrates removal from natural water and wastewater were analyzed in order to create effective and low-waste technology for obtaining high quality water. It has been established that the ion exchange method is quite effective for removing nitrates from water. In the paper, the processes of ion exchange removal of nitrates from water on low-axis anionite in DOWEX Marathon WBA in Сl- form were investigated. During the sorption of nitrates with a concentration of 186, 205, 223 and 2200 mg/dm3, it was established that the full exchangeable dynamic capacity was 1.075, 1.103, and 1.195, 1.698 g-eq/dm3, respectively. To regenerate anionite, solutions of ammonia as well as potassium chloride, ammonium chloride and potassium carbonate were used in this work. The choice of potassium and ammonium compounds is due to the prospect of further use of regeneration solutions for the production of liquid fertilizers.
Among all known inorganic pollutants of wastewater and natural water that adversely affect water bodies, different living organisms and human beings, iron compounds are the most common. Before discharging the wastewater into water bodies, it is important to remove iron ions from wastewater. The application of capillary materials in water and wastewater treatment is a promising direction of ecology and technology. The capillary properties of materials allow the development of quite simple, autonomous, highly efficient and energy-saving systems for water purification. The aim of the present paper was the investigation of the influence of the basic conditions of the filtration process with the application of capillary materia on the efficiency of iron ions removal. The initial concentration of the model solution, pH and temperature of the filtration process, as well as the contact area of the liquid phase with oxygen of the air were studied. The proposed method is appropriate for the treatment of water in the concentration range from 5 to 10 mg/dm3 with an optimum pH in the range of 4–7. The experimental data showed high efficiency of capillary materials application, providing sufficient removal of iron ions from low concentrated solutions, compared to the traditional method of precipitation. The main advantage of the capillary materials is the simplicity of their application, quite high degree of purification and there no need to consume electricity or additional reagents, which allows creating autonomous water treatment facilities and plants.
Analysis of the scientific and technical literature shows that there are quite a few methods of mine water processing. Reagent methods can be considered as the most promising and economically expedient. Mine waters are characterized by a high content of hardness ions and sulfates. The concentration of sulfates varies between 5–35 mg-eq/dm3, hardness – 10–40 mg-eq/dm3. It has been established that effective purification of water from sulfates can be achieved with the use of lime and 5/6 aluminum hydroxochloride. The efficiency of the process depends on the doses and ratio of reagents. The degree of softening and purification of water from sulfates increases with an increase in the dose of aluminum coagulant within certain limits. When using 5/6 aluminum hydroxochloride, the efficiency of water purification from sulfates is quite high and small amounts of chlorides are introduced into the water with the coagulant.
The main direction of the industrial development of Ukraine is the solving of the environmental pollution problems under the conditions of preservation of natural resources through complex use of raw materials with involvement of industrial wastes. The developed technology is intended for galvanic, accumulator, machine-building, mine and other enterprises, the wastewater from which contains ions of heavy metals. Heavy metal ions are extremely dangerous toxic substances because of a cumulative effect on aquatic organisms. In order to remove copper ions from aqueous solutions, the chemical precipitation with lime is used. The choice of reagent is associated with its cheapness. The most effective reagent precipitation of copper ions in the form of hydroxide occurs when the pH is raised to 10. In this work, the influence of sludge, which is formed as a result of water purification from copper ions, on the properties of cement was investigated. The effect was evaluated on the following properties: normal density of cement, hardening time, compressive strength at the age of 2 and 28 days and water separation coefficient. This allowed us to develop effective ways to their disposal. The developed method provides: a high degree of metal removal (up to 98-99%); simplicity of technological process; small capital and operating costs; complex technology of wastewater treatment process. Thus, the results of the study will contribute to the creation of low-waste and non-waste technologies for waste processing and disposal.
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