WATER AND WATER PURIFICATION TECHNOLOGIES. SCIENTIFIC AND TECHNICAL NEWS

DETERMINATION OF PHOSPHATE CONTENT IN WATER USING ORGANIC CHROMOGENIC COMPOUNDS

2025-10-21T03:43:48+03:00

Phosphorus compounds are introduced into natural waters in significant quantities as a result of anthropogenic activities. Agriculture and inadequate wastewater treatment are the main sources of phosphorus compounds. Increased levels of phosphorus compounds in water bodies lead to unbalanced eutrophication and significant changes in ecosystems. Therefore, monitoring phosphate levels is very important for maintaining the normal state of aquatic ecosystems. Spectrophotometry is one of the most widely used methods for measuring phosphate concentration. In the article, we reviewed existing spectrophotometric methods for determining the phosphate content in water and proposed a new method based on the use of a complex of metal indicators with metals. The principle of the method is based on the change of the metal complex with the metal indicator as a result of interaction with phosphate ions. Phosphate ions bind cations of metals such as zirconyl, since its phosphates have a very low solubility. The indicator released as a result of the destruction of the complex has a different color than the complex with a zirconyl cation. We experimentally tested the feasibility of using such metal indicators as chromazurol S, 8-oxyquinoline, arsenazo I, arsenazo III. The highest efficiency was demonstrated by the complex of chromazurol S with zirconyl ions, which is reflected in a clear change in color from purple to shades of crimson, red and orange for different phosphate concentrations. In the indicator system, we used a solution of chromazurol S with a concentration of 0.005 M and a solution of zirconyl nitrate with a concentration of 0.01 M. The ratio of the volumes of the solutions is 1:1. The proposed method of determination requires a significantly smaller amount of reagents than molybdate method.

HYGIENIC ASSESSMENT OF WATER QUALITY IN DOMESTIC DRINKING WATER SUPPLY SYSTEMS OF SAMARKAND

2025-04-03T01:38:39+03:00

The article provides a comprehensive hygienic evaluation of drinking water quality in both existing and prospective domestic water supply systems of Samarkand. The research analyzes key hydrochemical and microbiological indicators, emphasizing the implications of anthropogenic and abiotic contaminants found in local water sources. The study utilized extensive analytical data derived from over 720 samples collected from wells, clean water reservoirs (CWR), and the Zarafshan River, resulting in approximately 6480 laboratory determinations covering microbiological parameters, toxicological elements, organoleptic properties, and radioactive contaminants. Results indicate that the groundwater primarily serving Samarkand is generally safe, showing minimal microbial contamination and compliance with established hygienic standards. Groundwater quality has remained consistently high, without significant anthropogenic pollutants detected. However, the assessment revealed a notable deficiency in fluoride concentrations (0.14-0.28 mg/L), raising concerns regarding increased risks of dental caries among the local population. Additionally, certain local water intakes demonstrated increased hardness and mineralization levels due to natural geological processes, particularly noticeable at the Bolibaland and Chupon-ota water intakes. The research highlights the necessity for maintaining rigorous sanitary protection measures, especially due to ongoing anthropogenic impacts such as agricultural activities and uncontrolled excavation operations near the water intakes. Furthermore, long-term data analyses (1990-2024) suggest potential fluctuations in groundwater mineralization linked to climatic variations and irrigation practices affecting the Zarafshan River's hydrological regime. Conclusively, the current Samarkand water supply sources are robust and reliable, yet the establishment of additional water intakes, especially near Chubot village on the Zarafshan River, is recommended. This strategic development could significantly enhance the sanitary reliability and long-term sustainability of the city's water supply infrastructure, ensuring public health safety and improving overall water quality management.

MODERN APPROACHES TO WASTEWATER TREATMENT FROM PESTICIDES: A LITERATURE REVIEW

2025-10-21T04:18:30+03:00

The article presents a review of modern technologies for the treatment of wastewater contaminated with pesticides—persistent organic pollutants that exert a long-term toxic impact on ecosystems and human health. Due to their high stability, bioaccumulation potential, and low biodegradability, the presence of pesticides in aquatic environments poses a serious environmental problem, necessitating the implementation of effective wastewater treatment solutions. The focus is placed on four main groups of methods: oxidative, sorptive, biological, and combined approaches. Oxidative methods include ozonation, ultraviolet (UV) treatment, photocatalysis, and the Fenton process. These technologies are effective in decomposing persistent organic compounds but often require significant energy input. Sorptive methods — using activated carbon, zeolites, graphene-based materials, etc. — are characterized by high availability and simplicity in application, yet they require further regeneration or disposal of the sorbents. Biological methods, such as those involving activated sludge, biofilms, and microalgae, are environmentally friendly but limited in their ability to degrade poorly biodegradable substances. The most promising direction is recognized as the application of combined approaches that integrate the advantages of different methods while mitigating their drawbacks. Particular attention is given to the synergistic use of ozonation, UV treatment, Fenton processes, and biosorption. Such integrated systems can achieve a high degree of purification while reducing energy consumption and operational costs. It is substantiated that further development of combined technologies is a key direction for enhancing the efficiency of wastewater treatment from pesticides.

PROSPECTS FOR THE USE OF METAL OXIDES IN NANOFORM FOR INDUSTRIAL WASTEWATER TREATMENT

2025-04-03T04:25:56+03:00

The article presents the results of a theoretical study on the prospects for the use of metal oxides in nanoform for industrial wastewater treatment. The growing problem of water pollution by inorganic compounds, especially heavy metals (Pb²⁺, Cd²⁺, Hg²⁺, Cr⁶⁺), as well as phosphates, nitrates, and sulfates, creates a demand for innovative and eco-friendly purification technologies. Conventional treatment methods often lack effectiveness under conditions of high pollutant concentrations or complex wastewater composition. Nanostructured metal oxides, due to their high surface area, ion-exchange capacity, and catalytic activity, offer promising solutions for pollutant removal. The study provides an analytical overview of recent scientific literature on the properties, synthesis methods, and application of TiO₂, ZnO, Fe₃O₄, MnO₂, CuO, and Al₂O₃ in purification processes. The mechanisms of sorption, photocatalysis, precipitation, and complexation are discussed in detail. Influencing factors such as pH, particle morphology, temperature, pollutant concentration, and contact time are analyzed. Special attention is paid to the development of composite materials and surface-functionalized nanomaterials, which enhance selectivity, reusability, and stability in aggressive environments. The potential environmental impact, regeneration strategies, and barriers to large-scale application are also considered. The conclusions highlight the relevance of nanostructured metal oxides in the development of efficient, scalable, and sustainable technologies for water purification, in line with modern ecological and industrial challenges. Further interdisciplinary research is recommended to address safety, standardization, and cost-effectiveness aspects.

INCREASING THE EFFICIENCY OF WASTEWATER TREATMENT AT DAIRY INDUSTRY ENTERPRISES USING CAVITATION EQUIPMENT

2025-08-07T12:08:37+03:00

The article considers the problems of neutralization concentrated milky whey wastewater. The actuality of the research caused by the difficulty of utilization of acidic milky whey wastewater due to its unstable composition, high acidity and significant microbial pollution, which resulted in a high biological oxygen demand. In addition, the high chemical oxygen demand, which reflects a significant organic load and creates a problem for treatment technologies and ecological danger. The authors analyzed traditional and innovative treatment technologies with an accent on the advantages and disadvantages of each. Based on the analyzed data, it has proposed to use hydrodynamic cavitation as an auxiliary intensifying method in the technologies of neutralization concentrated milky whey wastewater. To realize it, the authors proposed a specially designed device of rotary-pulsation type. In order to determine the feasibility of the proposed solution, it is formulated by the tasks of evaluating the change in the microbiological indicator, chemical oxygen demand and biological oxygen demand under different treatment regimes. Also, determine the pattern of changes in temperature and dissolved oxygen concentration over the treatment time. According to the research results, the microbiological indicator of mesophilic aerobic and facultative anaerobic microorganisms showed the most significant decrease from at 3600 rpm within 10 minutes of treatment. At the same time, the neutralization of coliform bacteria has achieved after 2 minutes of treatment. The biological oxygen demand value showed a maximum reduction of 30 % at 3600 rpm during a 20-minute treatment cycle. The chemical oxygen demand value for the same time showed a similar pattern of decrease by 40 % at a linear temperature rise. In other words, the treatment in the proposed type of rotor-pulsation apparatus can be considerate as auxiliary equipment in the technologies of neutralization of concentrated milky whey wastewater. Recirculation treatment for 20 minutes at 3600 rpm is consider as optimal.

ANALYSIS OF CHALLENGES AND PROBLEMS IN THE APPLICATION OF ELECTRODEIONISATION FOR DEMINERALIZED WATER PRODUCTION

2025-09-22T14:37:02+03:00

The article presents an analysis of the challenges and problems that limit the widespread use of the electrodeionization method for water desalination. Nevertheless, this technology has already proven itself in the pharmaceutical industry, in the production of microelectronics and at thermal power facilities. But it also has prospects for wider application, for example, in the chemical and food industries, thermal power engineering, biotechnology, hydrogen production, etc. In combination with preliminary water treatment using the method of double stage reverse osmosis, has the potential to completely replace the use of cation and anion exchange filters for water desalination. The aim of this work is to review and analyze the fundamental principles and practical aspects of the application of electrodeionization, the design and operation of electrodeionization units, and possible approaches to improving their efficiency in order to obtain a high degree of water desalination. To this end, technological approaches to improving the design of electrodeionizers and the possibility of modifying ion-exchange resins in order to reduce energy consumption, increase selectivity and productivity, etc. are considered in detail. The main parameters of the electrodeionization process modes are determined, and the impact of modifying ion-exchange materials with water dissociation catalysts and varying the ratio of cation- and anion-exchange resins on the efficiency of the modules is assessed. The influence of the above factors on productivity, selectivity, energy consumption, continuous operation time of electrodeionization units, degree of ion exchange resin regeneration, degree of water purification, reduction of fouling of ion exchange membranes and degree of electrode corrosion has been analyzed.