Recycled Water Supply Research Articles

МОДЕРНИЗАЦИЯ ЭЛЕКТРОПРИВОДОВ В СИСТЕМЕ ОБОРОТНОГО ВОДОСНАБЖЕНИЯ

An effective solution for energy saving in the recycling water supply system of a petrochemical en-terprise based on the introduction of a variable-frequency AC electric drive as part of an electrome-chanical complex with an asynchronous squirrel-cage electric motor has been justified and consid-ered

Влияние кучного выщелачивания золотосодержащего сырья на окружающую среду

The issue of rational use of metal-containing raw materials goes hand in hand with the problem of minimization of environmental hazards caused by new technologies, which hampers the development of metal leaching, including gold leaching. The objective of this paper is the increase the mineral reserves of gold-mining enterprises via the application of leaching technology in stacks on the condition of minimization of damage to the natural environment. The results of the study of the impact of heap leaching complex on the surrounding ecosystems are provided based on the example of the stack of the «Kazakhaltyn» mine (the Republic of Kazakhstan), formed by tails of enrichment. The technological scheme of gold leaching and the parameters of its implementation, considering the minimization of consequences potentially hazardous for ecosystems, have been recommended. The calculation of parameters of hypothetically hazardous impact of gold leaching processes is provided for a stack of 6 m height; the time of leaching is 90 days; for four sorption stages, the coefficient of through-extraction of gold is 0.65. The specifics of the version of technology implying the use of recycled water supply to prevent contact with the environment are described. The processes of leaching affecting the environment and the preventive measures have been systematized. It has been demonstrated that emergencies are local, whereas sodium cyanide under the impact of atmospheric air and solar energy reacts with the generation of volatile short-lived hydrogen cyanide. It has been proved that the process of demetallization of mining and processing tails in the stack is a measure of environmental protection; it is not more hazardous than the traditional technology of handling processing tails. Such demetallization process is worth spreading.

TECHNOLOGIES FOR WASTEWATER TREATMENT FROM ARSENIC

The current recycling water supply of metallurgical enterprises does not completely eliminate the discharge of wastewater into environmental water bodies, where the maximum permissible concentration (MPC) of arsenic is 0.05 mg/dm3. Arsenic accumulates in large quantities in washing solutions for cleaning exhaust gases sent to produce sulfuric acid. In this case, a closed gas washing system is used, aimed at concentrating the washing water with arsenic to 10 g/dm3 and sulfuric acid to 40 g/dm3 in order to reduce the volume of wastewater discharge. Another source of arsenic contamination of the hydrosphere is the waters of tailings from enrichment plants, due to the possible oxidation of arsenopyrite and the formation of a soluble form of arsenic compounds.
 A number of methods for arsenic precipitation have been developed: pyrolusite, lime in the form of calcium arsenate; ions of ferric iron and other metals; adsorption by iron (III) hydroxide, aluminum hydroxide, carbon, etc.; sludge flotation; metal sulfides, sorption and extraction. The main criterion for the operation of purifying a solution from arsenic is the possibility of recycling the resulting sediment or the formation of its compounds with minimal solubility in aqueous solutions, allowing its burial in burial grounds.

Comparative analysis of reverse osmosis and ion exchange methods in the preparation of make-up water for recycling water supply of metallurgical industries

Comparative analysis of reverse osmosis and ion exchange methods in the preparation of make-up water for recycling water supply of metallurgical industries

Influence of soda-sulfate mixture on physicochemical properties of saponite suspension

This article deals with the problem of clayey sludge utilization of diamondiferous ore enrichment. Thickening of saponite sludge by means of chemical treatment is currently considered as the most effective way to clarify the volume of water sufficient to maintain the recycling water supply of the enterprise and, as a consequence, to reduce the volume of additional water introduced into the process. The authors propose a new coagulant for settling saponite sludge - sodium sulfate mixture, which is a by-product of aluminum production. The use of sodosulfate mixture will reduce the amount of waste for both the diamond mining plant's concentrator and the alumina production. The question of the mechanism of interaction of saponite sludge particles with the proposed reagent is considered. The aim of the research is to find physical and chemical regularities of interaction of clayey slime particles with sodosulfate mixture. Chemical and mineral composition of used raw materials, surface charge of clay particles, granulometric composition of experimental samples and their electrokinetic potential were determined in the work. The results of the studies showed that the mineral composition of the clay slurry includes the following minerals: saponite, kaolin, serpentine, beidelite, dolomite. The surface charge of clay particles is negative. The chemical composition of the soda-sulfate mixture is represented in the form of oxides: Na2O, SO3, CO2, Al2O3. The dependence of the electrokinetic potential on the mass of the mineral additive introduced into the slurry was revealed. It was noted that the absolute value of ζ-potential remains above 30 mV despite increasing the concentration of the additive, but coagulation of clay particles occurs and the system in question loses sedimentation stability at a concentration of sodium sulfate mixture of 14.4 g/l.

Развитие инженерно-технологического сопровождения процессов переработки нефти

The approach to engineering and technological support of oil refining processes at the refineries of PJSC Rosneft Oil Company is described. The results of technological monitoring of the main processes of oil refining are presented: atmospheric-vacuum distillation, reforming, isomerization, hydrotreating, catalytic cracking, visbreaking, delayed coking, production of elemental sulfur, bitumen production, as well as chemical and technological protection of equipment of installations, stabilization treatment of recycled water on local and centralized systems of recycled water supply of oil refineries. The given examples of completed tasks have shown the high efficiency of the built system of engineering and technological support in ensuring the operational, energy and economic efficiency of oil refining.

Improvement of methods for controlling power oil of cooling tower recycling water supply units at Rivne nuclear power plant

The relevance of the study is conditioned upon the fact that at nuclear power plants, water pumping units using energy oils are operated in the heat exchange equipment of power units. The diagnostic criteria of oils allow identifying defects in the operation of technological equipment. The purpose of the work – to increase the reliability of the operation of oil-filled power equipment by improving the monitoring of the physical and chemical properties of power oil TP-30. The main attention is devoted to increasing the reliability of the operation of oil-filled power equipment by improving the monitoring of the physical and chemical properties of TP-30 power oil. Experimental studies were conducted by chromatography, and gas and liquid extraction using appropriate laboratory equipment. When exploring the content of chemical elements in the segments of the thrust bearing of the cooling tower pumping unit, which is based on Sn, an increase in the content of copper Cu and Sb was observed, which exceeded the standard by an average of 1.2 and 1.1 times, respectively. Most of the analysed physical indicators of oil quality (water content, kinematic viscosity, flash point, acid number) did not demonstrate deviations from the standard values. Only an increase in the mass fraction of mechanical impurities by 0.0026% relative to the standard was noted during the incoming inspection of TP-30 oil. The results of the operational control of the oil in terms of a set of physical indicators fully complied with the established technological standards. The highest content of soluble gases in the oil (0.56% by volume) was recorded for propylene (C3 H6 ). It is recommended to use the relative content of soluble gases in Tp-30 oil to C3 H6 when identifying degradation processes. The absence of residuals of circulating power oil TP-30 in the surface waters of the Styr River during the operational event was established. Generalisations have been generalised about the necessity of expanding the diagnostic criteria for the quality of TP-30 oil, in particular, expanding the list of its physical indicators. In practical terms, the results obtained can be useful for monitoring the quality of other brands of petroleum oils in the systems of turbine units of nuclear power plants, which is important in terms of the safe operation of heat exchange equipment

PREPARATION FOR THE DISPOSAL OF SLUDGE FROM THE INDUSTRIAL WASTEWATER TREATMENT PLANTS

Due to the lack of local facilities for recycling, neutralization and treatment of wastewater at many metallurgical enterprises the wastewater is mixed; surface wastewater, blowdown of recycled water supply cycles, chemically polluted wastewater, spent cooling and washing liquids. As a result of the joint processing of the mentioned waste waters in sewage treatment plants, the specific sediments containing compounds of heavy metals and toxic substances are formed. The data on metal content in a solid phase of mixed sediments of different metallurgical enterprises is presented. It is noted that toxicity of sediments can be reduced by excluding the discharge of used concentrated solutions into the sewerage system, by regeneration of used technological and detergent solutions at the place of their formation. The scheme of sludge processing, which provides for their flocculation, gravitational thickening and mechanical dewatering, is proposed. It is shown, that the most efficient flocculant for treatment of sludge of mixed composition is a high-molecular-weight anionic flocculant with the content of ionogenic groups up to 10 %. The effective dosage is 5‒7 kg/t dry solids of sludge. For mechanical dewatering of flocculated sludge, chamber, membrane and belt filter presses as well as screw centrifuges (decanters) can be applied. Depending on the metal content, the dewatered sludge can be used for technical remediation of disturbed areas or for processing in the cement industry. Present study shows a schematic diagram for the preparation of mixed sewage sludge and dry industrial wastes of a metallurgical plant for technical remediation of disturbed lands. For processing sludge with water content between 65‒75 % in cement industry it is recommended to mix the mechanically dewatered sludge with dry wastes, such as abrasive dust and grinding powders, waste core mixtures for casting and other similar wastes.

Lebedinsky GOK’s mineral processing facilities: Current condition and development prospects

The concentration factory is one of the principal business entities in the production chain at Lebedinsky GOK. The processing facilities include two coarse crushing buildings, the concentration factory, the recycling water supply system, and the concentrate re-enrichment workshop which produces feedstock for metal conversion. Crushing of ferruginous quartzite ore is carried out down to a size of 0–350 mm within a single stage on coarse cone crushers KKD 1500×180. The coarse crushing products go to the concentration factory for the autogenous milling and subsequent magnetic separation. The annual capacity of the concentration factory is 21 Mt of the concentrate with the iron mass fraction less than 69.5 % and 12.2 Mt of the concentrate with the iron mass fraction higher than 69.5 %. Within the operating life of the concentration factory, many production data exceeded the project values (production output, equipment efficiency and capacity, concentrate yield). The demand for the stable supply of the iron products of Lebedinsky GOK promoted its upsurge and increase in capacity. The development strategy of Lebedinsky GOK includes implementation of both large-scale projects and many smaller events aimed to enhance operating efficiency and stimulate production optimization. Effective and purposeful work toward the technological advancement and introduction of new equipment enables the concentration factory at Lebedinsky GOK to produce concentrate of the desired quality and quantity to satisfy the growing needs of the iron product market.

Study of the possibility of using zeolite and diatomite in the treatment of oil-contaminated wastewater

Numerous harmful substances of anthropogenic origin that are released into the environment, including petroleum products, are the result of the uncontrolled discharge of industrial wastewater into natural water bodies. Operation of oil refining and petrochemical industry enterprises, gaseous emissions and effluents of industrial enterprises, numerous oil and NP spills as a result of accidents and fires at oil storage facilities and oil refineries lead to pollution of water and soil with considerable amounts of crude oil and products of its processing and create a serious threat to the ecology of regions of Kazakhstan. A cardinal solution to the problem of protection of water bodies from pollution by wastewater polluted by oil and NP is to organize such water management of enterprises, under which the system of recycling water supply is developed as much as possible and the discharge of wastewater into water bodies is minimized. Currently, the sorption method of water purification is the most environmentally safe and expedient. When selecting a sorbent for sorption much attention is paid to its sorption characteristics and the availability of raw materials. In addition, the choice of a sorbent depends on such factors as the quality requirement for purification, the condition of pollutants, the stages of purification and others. A wide range of natural sorption materials used in water treatment and water treatment is known. Natural materials based on modified diatomites and zeolites from Kazakhstan deposits are investigated in this work.

Managing emerging pathogen risks in recycled water

The COVID-19 pandemic raised the public profile of wastewater-based infectious disease monitoring. General media coverage about wastewater detection of SARS-CoV-2 (the COVID-19 coronavirus) increased community awareness of the potential use of wastewater for the detection and surveillance of emerging diseases and also heightened recognition of the potential for wastewater to harbour and convey a variety of pathogens. This has also generated questions about the potential public health impacts of emerging pathogens, such as SARS-CoV-2 and mpox, in sewage and recycled water. To ensure water security in an era of climate change, water recycling is increasingly important in Australia and other water-stressed nations and managing disease risks in integrated water management is thus of critical importance. This paper demonstrates the existing risk management provisions for recycled water and explores potential issues posed by novel and emerging pathogens. First, a synopsis of some key emerging and re-emerging human pathogens is presented and the risks associated with these pathogens in the context of recycled water provision is considered. Then, an overview of the engineered treatment systems and regulatory framework used to manage these emerging risks in Australia is presented, together with a discusion of how emerging pathogen risks can be managed to ensure safe recycled water supply now and into the future.

ASSESSMENT OF THE CONDITION OF THE POLTAVA REGION WATER SUPPLY COMPLEX

Assessment of the state and rationality of the operation of the water management complex (WMC) of the Poltava region is an extremely relevant study of the present, since the WMC was created in the 60s-70s of the last century and actively provides the sectors of the economy and the population with water resources. The study aim is to assess the water resource potential as the basis for the functioning of the water-chemical complex, to determine the levels of technogenic impact on the water resource potential. A review of the sources was carried out using the Google Scholar database by filtering for the period from 2010 to 2021 and mainly revising publications on numerous samples related to monitoring and control of the state of the water management complex of the Poltava region. According to the official report of 2019, the rivers Dnieper, Psel, Sukhoi Omelnik, Uday received an assessment: slightly polluted waters, the Vorskla and Orzhitsa rivers are moderately polluted waters. The main ingredients responsible for the low water ratings as of 2019 are phosphate ions, manganese, as well as nitrite nitrogen, total iron and BOD5. The manganese content was measured in three rivers, and the average estimate ranged from 5.8 in the Psel River to 11.85 in the Vorskla River. According to the Regional Office of Water Resources in the Poltava region, in 2019, 109.8 million m3 were withdrawn from the natural water bodies of the Poltava region, namely underground water bodies, which is 4.6 million m3 less than in 2018 (or 4.0 %), including 69.83 million m3 (which is 3.29 million m3 or 4.5 % less than in 2018). However, the total water intake in the region over the past 10 years has decreased by 2.2 times. A positive trend is that all discharges occur at treatment facilities of housing and communal services. There is no discharge of return water without treatment into surface water bodies of the Poltava region; however, within the boundaries of settlements there is a discharge of under-treated municipal wastewater and runoff from the urbanized territory. Consequently, balancing water use is possible by introducing waterless, low-water and water-saving technologies in all sectors of the economy, maximum use of water in recycling water supply systems; replacement of physically and morally worn out water supply and water protection equipment, etc.

Basic Principles of Creating and Using the Waste-free Technologies in the System of Recycled Water Supply and Water Purification

The need to protect the environment makes it necessary to significantly change the general approaches to environmental efficiency of production, to minimize the impact on nature at the present level of productivity and quality. Today instead of the temporary measures aimed at overcoming the effects of pollution, the long-term measures are being taken more and more often at the design and construction stages to nullify the causes of pollution in advance rather than to have its effects in the future. The processes and devices that have been previously used to collect and dispose the industrial waste are now considered a passive approach to environmental protection. The matter is that the amount of waste generated during the production process remains almost unchanged, and this does not meet the new environmental requirements. The active approach involves creating the modern low-waste and non-waste technologies that can efficiently use raw materials in production processes, as well as converting the waste into easily recyclable components that are least harmful to the environment. The article considers the conceptual principles that show the essence of the active approach to improving the industrial technologies in order to protect the environment. It is mainly focused on studying the features of recycled water supply and water purification.

Possible use of precipitation for water recirculation system of a machine building site: analysis

An urgent task for industrial enterprises of metallurgical complexes is to create a rational and most environmentally friendly cycle of recycling water supply. One of the options for optimizing the efficiency of the water supply system is the collection and use of precipitation. This article presents the conducted studies of the chemical composition of atmospheric precipitation collected from the roof of the mechanical assembly shop of a machine-building enterprise in the Moscow region, as well as the possibilities of their further use in the circulating water supply cycle of this enterprise. At the first stage of the experiments, a primary assessment of the chemical and microbiological indicators of the quality of atmospheric precipitation was carried out depending on the season, and the data obtained were compared with the requirements of regulatory documents. In order to inhibit biological processes occurring during the collection and accumulation of atmospheric precipitation, a technology for the disinfection of effluents was proposed, based on the use of hydrodynamic cavitation devices. A method for calculating the applied hydrodynamic devices is presented. The technology of ultrafiltration purification through ceramic membrane filters was proposed as the final stage of additional purification of atmospheric precipitation but with standard values. This stage allows with a high degree of efficiency to remove from the water micro-impurities of suspended solids, as well as formed in the process of hydrodynamic treatment of insoluble compounds. The proposed technology of hydrodynamic treatment of atmospheric water with subsequent ultrafiltration was subsequently successfully tested in real conditions. The calculation of the expected volumes of formation and collection of atmospheric precipitation was carried out with an assessment of the possibility of reducing the volume of water consumption from an artesian well. The high prospects of using atmospheric precipitation for feeding individual operations (galvanic processes, boiler water) have been confirmed. This research was carried out under a programme aimed at giving support to young research and teaching staff of D.Mendeleev University of Chemical Technology of Russia; Application No. К-2020-015.

Root cause analysis for membrane system validation failure at a full-scale recycled water treatment plant

Ultrafiltration (UF) membranes can be used as a standalone process for the removal of enteric virus and are often combined with reverse osmosis (RO) processes for use as the pre-treatment to manage microbial risks. In this study, a water utility experienced multiple validation failures in one of its UF plants with virus log reduction values (LRV) as low as 0.79 reported. This resulted in the suspension of recycled water supply to customers and initiated a comprehensive root cause analysis to identify the reason for the unusually rapid membrane degradation and virus removal validation failure. Polyethersulfone (PES) membrane fibres were sampled from the used modules and a systematic autopsy was undertaken. The FTIR spectroscopic structural analysis revealed oxidative changes in the PES polymer structure. Thermal analysis by differential scanning calorimetry showed changes in the melting point of the PES and suggested a loss of the pore-forming polymer polyvinylpyrrolidone (PVP). Streaming potential analysis showed a decrease in the negativity of the surface charge from −50 mV to −30 mV at pH 7. Tensile testing revealed a 9% and 47% decrease in the breaking force and elongation at break of the used fibres respectively. The pore size evaluation challenge testing of the used fibres showed no rejection of nanoparticles with 150 nm diameter and smaller. The autopsy investigation suggested that the unusually rapid membrane degradation was due to chemical oxidation resulting in changes in the PES structure and physical properties. Detailed on-site investigation was then undertaken and it was suggested that the failure to operate appropriate chemical enhance backwash (CEB) was the main cause for the unusually rapid virus LRV reduction. Finally, CEB water sampling and analysis were undertaken, which confirmed the recommendations from membrane autopsy and site investigation. A range of system improvements (system control, new inline static mixer, CEB water quality monitoring, etc.) were implemented. Based on the root cause analysis and system improvements, the maximum virus LRV of 4 has been maintained since then.

How much potable water is saved by wastewater recycling? Quasi-experimental evidence from California

Recently, California has made large investments in wastewater recycling to replace applications that use potable water. It may be expected that the use of recycled water reduces potable water use, but such an equivalency is not assured. The addition of recycled water infrastructure in a large Californian water district creates a natural experiment where this work tests how recycled water usage affects primary potable water. This is done using econometric methods for causal inference in an observational setting that mirror a randomized control trial (RCT). From 2001 to 2014, a number of public parks were given recycled water infrastructure, while others in those regions remained exclusively on potable supply. A two-way fixed effects regression is used to produce a difference-in-differences estimate of the average treatment effect of recycled water on total and potable water usage. The results indicate that potable water usage is reduced significantly when a park is connected to the recycled water supply. The estimated rate of displacement in the study period is 81.7%, meaning each unit of recycled water use avoided 0.817 units of potable water usage, which implies the connection of parks to recycled water supply increases total water use. The analysis provides, to the best of our knowledge, the first empirical estimate of the water savings claimed by urban water recycling programs, and the first empirical estimate of displacement using quasi-experimental methods. The methodology can be utilized to evaluate the effectiveness of recycling programs around the world.

Технологический прорыв аграрно-пищевых инноваций молочного дела на примере универсального сельхозсырья. Обратный осмос

Aim. Consideration of the membrane technology process – reverse osmosis – by directed and controlled processing of whey and its filtrates through special semipermeable partitions (filter membranes) with a pore size from 0.1 to 1.0 nm, carried out at a pressure of 3.0 - 10.0 MPa with the release of particles (cutting off) with a molecular weight of 100 Daltons. Reverse osmosis allows you to concentrate all the compounds of whey and filtrates, separating almost distilled water (condensate). Discussion. In the molecular sieve separation system, reverse osmosis logically continues the membrane treatment of filtrates (permeates) of native, as well as separated whey and their microfiltrates, ultrafiltrates, nanofiltrates and diafiltrates. In principle, the reverse osmosis process should be implemented to pre-concentrate the whey, which will eliminate its loss (draining) and expand the range of use. OO is promising for processing salted whey with the removal of unwanted sodium chloride, as well as for cleaning the condensate of evaporation plants from the components of dairy raw materials that come with foam and secondary steam. Conclusion. In general, for the dairy industry of the food industry of the agro-industrial complex, reverse osmotic treatment is necessary for the implementation of a closed production cycle with a recycled water supply.

Improving the quality of recycled water by pulsed electromagnetic treatment

The relevance of this work is of exceptional importance and is widely used in technological processes at most industrial enterprises, including oil refineries. Industrial enterprises of the oil industry are subject to strict controls on environmental protection, water consumption, and the quantity and quality of wastewater discharged. This article presents data on the treatment of recycled water before the clarification section by reverse osmosis using an electromagnetic treatment device. The authors made a pilot reverse osmosis unit with a capacity of 0.370 m3/h, the permeate output (for purified water) was 0.3 m3/h, the concentrate discharge was 0.07 m3/h. The test bench operates in a closed circuit, i.e. the permeate and brine are returned to the original container. The technological scheme of purification to the standards that meet the requirements of makeup water, as well as the technical specification for the design of industrial recycling water supply systems, has been developed.

Adsorptive extraction of chromium (VI) ions from corrosive aqueous solutions

Chromium is one of the most effective metals used for protection and decorative coating of various products. However, chrome plating typically occurs in a strongly acid medium, thus involving the formation of dangerous and corrosive solutions. In this article, we investigate the possibility of removing chromium from such solutions using carbon adsorbents, which allow for almost complete extraction of the metal from production solutions up to a residual content of no more than 0.05 mg/dm3. A significant advantage of carbon adsorbents is their ability to extract chromium (VI) ions without chromium reduction to the trivalent state. It was established that the sorbent under study exhibits the maximum sorption capacity in a strongly acidic medium at pH = 1.2–2.5. This medium causes the formation of a Cr2O7 2- dimer in the solution, which is an adsorbed ion. A scheme of a production unit for chromium adsorption from solutions of electrochemical production was proposed. The choice of an adsorber with a fluidized bed was determined by the maximal interaction of the flow with the adsorbent in such reactors. The adsorber design in the form of a cylindrical column with tapered upper and lower parts assumes installation of distribution grids inside the apparatus. It is proposed to forward the chromium-containing solution of electrochemical production remained after the averaging tank directly to the adsorber with the loading of the carbon adsorbent. In order to ensure the continuity of the extraction mode, it is necessary to apply two parallel working adsorbers, whose technical parameters were calculated to be as follows: the diameter of 1.2 m; the height of 7.5 m; the loading volume of 5.9 m3; and the loading height of 6 m. The calculated process parameters were determined: the linear flow rate along the walls of the adsorber – 12.75 m/h; the duration of the apparatus operation before coal regeneration – 21 days. The proposed scheme can be recommended for recycling water supply.

Improvement of quality of recirculated water supply of oil refineries

The relevance of this work is associated with the need to reduce the volume of water used by returning it to the start of the technological process. Thus, the work aims to improve the quality of the recycled water supply to petrochemical and oil refineries, in particular Atyrau Refinery LLP. This article provides data on purification of blowdown water by reverse osmosis method. A pilot reverse osmosis unit with a capacity of 600 l / h has been manufactured and a technological scheme for purification to standards that meet the requirements of make-up water has been developed, as well as a technical task for the design of industrial recycling water supply systems and appropriate recommendations have been provided.