Sludge Storage Research Articles

Degree of salinization of technozems of recultivated sludge storage depending on their constructions and economic use

Degree of salinization of technozems of recultivated sludge storage depending on their constructions and economic use

Increasing the level of environmental safety of drilling sludge storages

The main sources of soil pollution due to the development of oil and gas fields are analyzed. It is shown that the main sources of oil products entering the soil are sludge accumulators and drilling barns. A new construction of a drilling barn and a scheme of reclamation of the existing ones are proposed. The implementation of such developments will minimize the ingress of oil-containing fluids into the soil and increase the level of environmental safety of oil and gas development processes.

Remediation of Soil Containing Sludge Generated by Printed Circuit Board Production and Electroplating

This paper examines the environmental conditions at the premises of printed circuit boards (PCBs) manufacturers, which have electroplating plants. It provides a brief overview of the key aspects of adverse environmental impacts of wastes generated by PCB manufacture and electroplating plants. The aim of this research was to improve the test method for evaluation of wastewater effect on the soil salinity at the premises of PCBs manufacturers. The object of research was the process of extraction and use of copper from wastewater generated by PCBs manufacture and electroplating. As an example, the process of sludge formation during PCBs etching has been reviewed. With the etching line capacity of 14 m2/h, one-shift manufacturing process will result in the production of up to 2,500 kg of sludge monthly. For enterprises with capacities of 2,000–4,000 m2 circuits, this means annual accumulation at their premises of up to 70 tons of wastes in the form of sludge. Estimates suggest that the upper half-meter layer of the aeration zone will be qualified as slightly saline in one year after accumulation of the sludge. In subsequent years, the salt content will increase and saline soil can be found at the depths of 1.5–2 m over ten years of storage. The authors of this paper propose to treat spent etching solutions applying regeneration technology in order to reduce the amount of sludge. With this technology, it is possible to use the extracted metal as a secondary raw material for copper production and re-use the regenerated solution in PCBs etching. This paper provides estimated hazard indices calculated for the storage of sludge at the manufacturer’s premises before and after the implementation of the proposed technology. With regards to findings of the study, it has been proposed to reuse copper recovered from wastes as a raw material for the industry.

Numerical Simulation of Highly Saline Wastewater Discharge into Water Objects to Improve Discharge Devices

The expansion of large-tonnage chemical production (primarily, of mineral fertilizers) calls for the development of new methods for discharging excess brines into surface water objects. This task is complicated by the fact that, due to the suppression of vertical turbulent pulsations, “heavy” brines may spread over considerable distances in the near-bottom region without any significant decrease in their concentration. Some suggestions for optimizing exhaust structures designed to discharge wastewater containing heavy impurities are proposed based on numerical modeling. The calculations based on solving the three-dimensional problem with different wastewater discharge conditions have shown the structures providing location of exhaust devices near the reservoir surface to be the most efficient ones. However, such structures are difficult to implement in a certain reservoir section. In this case, an easy-to-implement and quite efficient configuration is that including bottom arrangement of exhaust devices and selective intake of highly saline wastewater from sludge storage facilities. Irrespective of the chosen scheme for disposal of highly mineralized wastewater, their discharge must be carried out in strict coordination with the hydrological regime of water intake. This approach will provide the most efficient use of the assimilative capacity of water body and the best way to reduce the ecological impact on both the water body and the environment.

Manmade deposit formation and geological environment monitoring at salt dumps and sludge storages

The integrated subsoil management is currently in the spotlight in the world. In this regard, associated minerals and waste should be widely involved in satisfaction of needs of production. To this effect, it is required to define predictive indicators of the status of provision and consumption, to develop methods of waste piling and storage, to estimate extra expenses connected with arrangement of waste storage facilities and to undertake predictive performance appraisal of new processing technologies for mining waste. In the Republic of Belarus, the most serious adverse impact is exerted on the geological environment by the geographically distributed industries and, for the first turn, by the potash mining industry, which is associated with new manmade formations—salt dumps and sludge storages. This waste represents water-soluble salt, insoluble residue and mother brine. Each component has a harmful influence on the environment. This article presents the studies on justification of geological environment monitoring at such manmade deposits. The research findings are the framework for the protection of adjacent areas of salt dumps and sludge storage facilities from the aggravating impact of this mining waste.

Emission characteristics of bioaerosol and quantitative microbiological risk assessment for equipping individuals with various personal protective equipment in a WWTP

Wastewater treatment plants (WWTPs) are a nonnegligible source of bioaerosols that can pose health risks to workers and nearby residents. Thus, this study systematically investigated the emission characteristics of the size distribution and concentration of Staphylococcus aureus bioaerosol in a WWTP. Then, the research focused on the quantitative microbiological risk assessment (QMRA) of workers and nearby residents for equipping them with various grades personal protective equipment (PPE). Results showed that the peak proportion of the size distributions of bioaerosol particles in the three sources all obtained a size range between 3.3 and 4.7 μm. In the residential building, the peak proportion was larger (>7.0 μm). Referring to the three sources, the average bioaerosol concentrations were in the following sequence: inverted umbrella aerator tank > residual sludge storage yard > microporous aerator tank. The health risks of residents were generally 1–2 orders of magnitude higher than the other two exposure scenarios and were clearly beyond the benchmarks. Meanwhile, the health risks of the field engineer were usually lower than those of the staff at the residual sludge storage yard. In general, equipping workers and residents with PPE could at least decrease the health risks by one order of magnitude, and higher-grade PPE could appropriately promote the reduction of health risks. This research systematically delivered a series of novel data about the emission characteristics of Staphylococcus aureus bioaerosol in a WWTP. It advanced the understanding of the quantitative health risks of equipping individuals with various PPE.

ENVIRONMENTAL SAFETY EVALUATION FROM GALVANIC SLUDGE DURING LONG-TERM STORAGE

The article analyses the ecological state of the soil in an enterprise with a galvanic shop that produces chips and microcircuits. The problem of production waste storage in open areas is investigated. Environmental hazards during long-term storage of sludge have been identified. The composition of the sludge obtained after sewage treatment of the production of the copper line was investigated. A method for predicting the level and depth of soil salinity during long-term sludge storage is proposed. The experience of reuse of copper extracted from sludge is analysed.

Studying the Formation Features and the Extent of Diffuse Pollution Formed by Large Industrial Complexes: Case Study of the Solikamsk–Berezniki Industrial Hub

The issues of formation and assessment of diffuse pollution of water objects in the zones near large mining and chemical industrial complexes are discussed. The study object is the Kama River (Kama Reservoir) in the zone of influence of the Solikamsk–Berezniki Industrial Hub. The major flows of pollution are due to seepage recharges from the operating and removed from service sludge storage sites and storages of liquid and solid wastes. The anthropogenic impact was identified, and its qualitative and quantitative characteristics were evaluated based on expedition data, state monitoring data, and mathematical simulation. The formation mechanisms are considered for the local pollution zones in the Kama River segment (the Kama Reservoir), in the context of considerable vertical heterogeneity―the concentrations of pollutants in bottom zones can be an order of magnitude higher than their concentration in the surface layer. More than 90% of pollution in this part of the Kama Reservoir were found to arrive in diffuse manner. Six types of measures were proposed for reducing the diffuse runoff in the zone of influence of the Solikamsk–Berezniki Industrial Hub.

Technology for Restoration and Ecological Rehabilitation of Lands Violated by Toxic Reagents

A technology has been developed and tested on an industrial scale for the restoration of disturbed lands contaminated with alkali-containing sludge waters. In the process of field research, the use of various neutralized soil neutralizers in the area adjacent to the alumina sludge storage facility was verified. Tests confirmed that the most effective neutralizer of alkaline soil is ammonium sulfate, which reduces the pH of the aqueous extract from 10,2 to 8,2 units. Using non-toxic technogenic materials, substrate compositions have been developed to restore the potentially fertile layer and the technology of ecological rehabilitation of disturbed lands for their subsequent use has been tested.

Environmental monitoring of the reclaimed sites of JSC “EVRAZ ZSMK”sludge dump

For conservation of technologically disturbed lands, various methods of reclamation are used to prevent their negative impact on the environment. At the same time, technological methods are used, including changing the technology of waste storage, changing the state of storaged products using briquetting and granulation, creating mechanical barriers that prevent the spread of dust or continuous coating with non-dusting material, and the physicochemical method – creation of a protective layer using foam or hydro-dusting in order to stabilize a dusty surface. The most environmentally effective is the biological method – creation of a protective vegetation cover. This method is of particular relevance due to the phytotoxicity of the technogenic substrate for sludge dumps and the difficulties of creating a stable vegetation cover. Taking into account the industrial and environmental characteristics of the waste in sludge dumps of JSC “EVRAZ ZSMK”, an assessment of the physiological state was carried out as part of environmental monitoring and the chemical composition of plants growing in the reclaimed areas of this technogenic object was analyzed. A comprehensive assessment of the environmental safety of the use of sewage sludge from urban wastewater treatment plants on the substrate of the sludge storage facility as the main soil improver is given.

PURIFICATION OF SEWAGES GALVANIC PRODUCTIONS: ECOLOGICAL AND ECONOMIC ASPECTS

There is an urgent need for copper in Ukraine, which is used in various industries: electrical engineering,mechanical engineering, construction, food and chemical industries. Meanwhile, there is insufficient exploration ofcopper ores in Ukraine. At the same time, galvanic and PCB manufacturing are sources of environmental hazard.The object of the study is the process of using copper from sewage production boards and electroplating processes.The purpose of the work is environmental and economic justification for the removal of copper from wastewater forits further use. The aspects of mining (copper) in a mine and open method are described. The data on exploredreserves of copper ores in Ukraine and real needs for copper for the successful operation of industrial enterprisesare presented. The condition with the presence of sludge during the work of the etching lines of the printed circuitboards during normal operation at full capacity is considered, and it is established that for the productivity of theetching line 14 m2 / h the amount of sludges per month of work in one shift will be about 2400-2500 kg. This leadsto the accumulation of significant amounts of hazardous waste on the territories of enterprises, which causeenvironmental damage. In order to avoid the accumulation of sludge on the territory of the enterprises it is proposedto use the technology of regeneration of waste digestion solutions, in which the recovered metal is used as secondaryraw material for copper production, and the recovered solution is reused for etching of printed circuit boards. Thescheme of the line of etching of printed circuit boards with a lead for regeneration is offered. The introduction of anew wastewater treatment technology with only one plant can bring more than 2.8 million UAH of economic effect.The total sludge hazard index for the current state of sludge storage in the territory of enterprises (0.045) and afterthe implementation of wastewater recovery (100) has been determined.

Изменения микробиома как индикатор восстановления природных сред содового шламохранилища АО «Березниковский содовый завод»

Изменения микробиома как индикатор восстановления природных сред содового шламохранилища АО «Березниковский содовый завод»

Reduction of Anthropogenic Impact of Alumina Sludge Storage on the Environment

To reduce the impact of alumina sludge storage on the environment, a number of environmental technical solutions have been tested and implemented. Laying a polymeric film on a bed slurry maps and the construction of artificial water level decrease led to the absence of anthropogenic interference, and created favorable conditions for ensuring the stability of the ecological system in the area adjacent to the sludge storage. After the implementation of the environmental events area negative impact of sludge decreased to 150–200 m from the contour of the slurry of the map, outside this zone there are qualitative changes in the chemical composition of groundwater, the alkaline reaction of the environment decreases less than 8.0 units, chemical composition of groundwater is virtually the same background.

Combined aeration and mixing system and its use in practice

The article deals with combined systems, which are mainly used in wastewater treatment plants for the purpose of aeration and mixing. These systems are mainly installed in activation reactors, but their use is also possible, for example, in sludge storage tanks. The combined systems are capable of guaranteeing the required values of relevant monitored pollution indicators at the WWTP effluent. The aim of this article is to describe the activation reactor control algorithm with the combined system. Reliable functionality is proved by the presented average values at the WTP effluent, which meet the required emission limits set by relevant permits.

Metoda prerade tehnogene sirovine hroma

Taking into account the existing demand for chromium concentrates, the extraction of chromium from technogenic formations of sludge storages of the tailings of chromium ore beneficiation is an important practical task. The comprehensive utilization of beneficiation sludge will increase the profitability of production and solve the environmental problems of the region. The importance of solving the problem of involving in processing tailings is connected not only with the environment but also with the need to increase the production of chromium. Modern gravity enrichment technologies make it possible to efficiently produce chromium concentrates from large and medium fractions of chromite-containing ores, while finely divided sludge is practically not extracted due to the difficulty of separating complex minerals into concentrates and waste rock. This paper presents the results of studies on the gravity processing of tailings. The technology includes the enrichment of the fine fraction-0.2+0 mm of tailings of the dressing plant of chromite-containing ores by gravity methods using a KNELSON centrifugal separator. In technology, the efficiency of the operation of gravity enrichment is provided by the preliminary activation of the fine fraction in a solution of sodium bicarbonate (NaHCO3). With gravitational enrichment, the total chromite concentrate was obtained containing 51.3% Cr2O3. The output of concentrate was 41.7%. The extraction of Cr2O3 in the concentrate was 68.1%.

Feasible utilization of waste limestone sludge as filler in bituminous concrete

The dimensional limestone industries produce a substantial amount of waste limestone sludge during the polishing of stone slabs. The storage and disposal of this non-biodegradable sludge cause issues regarding environmental pollution, shortage of disposal land, increase in transportation cost, and several other associated problems. This study investigated the usability of dried limestone sludge (LS) instead of conventional stone dust (SD) as filler in bituminous concrete mixes. The performance of SD and LS incorporated mixes in several aspects was compared, and the amount of LS needed to ensure optimum bituminous mix behavior is determined. The physical and chemical properties of both fillers were initially explored. Then bituminous concrete mixes having both fillers added at four different proportions (4, 5.5, 7.0, and 8.5% by weight of aggregates) were prepared using the Marshall mix design method and their optimum bitumen contents (OBC) were determined. The performance of both mixes was studied. LS mixes displayed paramount rutting resistance, fatigue resistance, indirect tensile strength, ravelling, and resilient modulus than conventional mixes. It mostly attributed to the fine nature of LS, which ensured its better distribution. LS mixes also had lower OBC than SD mixes due to lower porosity and bitumen extender action of LS. LS displayed a good affinity towards bitumen due to calcite in its composition, which led to excellent adhesion and moisture resistance in its mixes. The test results suggested that the utilization of chosen LS as filler at an optimum filler percentage of 6.45% can result in formation of bituminous mixes with satisfactory engineering properties, lower bitumen content as well as lower greenhouse gas emissions.

Evolution of microbial community during dry storage and recovery of aerobic granular sludge

Aerobic granular sludge (AGS) was imbedded in agar and stored at 4 °C for 30 days, and then the stored granules were recovered in a sequencing batch reactor fed real wastewater within 11 days. Variations in microbial community compositions were investigated during dry storage and recovery of AGS, aiming to elucidate the mechanism of granular stability loss and recovery. The storage and recovery of AGS involved microbial community evolution. The dominant bacterial genera of the mature AGS were Zoogloea (relative abundance of 22.39%), Thauera (16.03%) and Clostridium_sensu_stricto (11.17%), and those of the stored granules were Acidovorax (26.79%), Macellibacteroides (12.83%) and Pseudoxanthomonas (5.69%), respectively. However, the dominant genera were Streptococcus (43.64%), Clostridium_sensu_stricto (12.3.6%) and Lactococcus (11.47%) in the recovered AGS. Methanogens were always the dominant archaeal species in mature AGS (93.01%), stored granules (99.99%) and the recovered AGS (94.84%). Facultative anaerobes and anaerobes proliferated and dominated in the stored granules, and their metabolic activities gradually led to granular structure destruction and property deterioration. However, the stored granules served as carriers for the microbes originated from the real septic tank wastewater during recovery. They proliferated rapidly and secreted a large number of extracellular polymeric substances which helped to recover the granular structure in 11 days.

Use of Alumina Production Waste Red Mud During Molten Sulfur-Containing Slag Granulation

Versions are provided for the use of red mud (RM) as a substitute for expensive lime and limestone used for cleaning industrial gases with toxic sulfur compounds emitted into the atmosphere in large quantities. Laboratory and industrial tests reveal the absorption capacity of RM for cleaning gases from sulfur discharged into the atmosphere by furnace thermal power stations, sintering machines, and steel furnaces. It is established that the hydrogen sulfide content in the atmosphere during granulation of slag with the participation of RM is reduced by a factor of ten. In addition, the ecological efficiency of air cleaning from sulfur-containing gases released in granulation areas from molten blast furnace slag is demonstrated. Improvement of technological properties of metallurgical granulated slag that will promote a high demand for this material in the construction industry is revealed. A reduction in the risk of new hazards in storage areas and RM in sludge storage will resolve environmental problems of these regions.

ГИДРОМЕТАЛЛУРГИЧЕСКАЯ ТЕХНОЛОГИЯ ПЕРЕРАБОТКИ ЦИНКСОДЕРЖАЩИХ ШЛАМОВ СТОЧНЫХ ВОД ПРОИЗВОДСТВА ХИМВОЛОКНА

Large areas of storage sludge pose a risk of contamination of soil, groundwater and crops, respectively, pose a significant risk to humans and other living organisms, because heavy metals accumulated in plants are included in food chains and enter the gastrointestinal tract with foodstuffs. Over time, sludge stores overflow, causing the need to build new structures. The introduction of sludge recycling technologies will free up the area occupied by sludge storage facilities, eliminate the cost of building new sludge and profit from the extraction of valuable components. Such, for example, is zinc, whose content in natural raw materials is 1-3 %, and in the waste of the production of viscose fiber 6.5-40 % (depending on the range of products, and reagents used for wastewater treatment). Zinccontaining sludge at medium-sized enterprises is 1,000,000 tons, allowing it to process that amount of sludge with a capacity of 10 tons per hour for 10 to 15 years. In the early works in the laboratory, physical and chemical laws of zinc-containing sludge processing were established and technological process of sludge utilization into zinc sulfate was developed, the composition and physical and chemical properties of zinc-containing sludge were investi-gated, the conditions of processing and rational ways of utilization were determined, the influence of temperature on contact duration, reagent concentration, mixing intensity was investigated for the zinc hydroxide extraction process, zinc content purification technology was proposed, impurity solution, comparative feasibility studies and cost effectiveness of sludge processing were performed. The paper presents a study of hydrometallurgical method of processing zinc-containing sewage sludge by leaching. The removal of zinc from the sludge is carried out on a semi-industrial installation. To study the particle size distribution of the source ore, wet sieving method is chosen. Phase chemical analysis on the forms of zinc is carried out. Also, X-ray and thermogravimetric analyzes are applied to study the real composition of the sample. On the basis of a series of experiments on a semi-industrial installation, the main stages of technological process are identified and investigated. According to the results of the research, the technological process of obtaining zinc sulfate from zinccontaining sludge production of viscose fiber is developed. It is proposed to divide the process into separate stages, in order to develop a flexible technological scheme, which allows the processing of different raw materials. For complete and effective extraction of zinc, the insoluble residue after the leaching step is proposed to be treated with a nitric acid solution, which allows to obtain an additional product – calcium nitrate enriched with micro-impurities. According to preliminary ecological and economic calculations, the profit from the sludge processing for one year will be about EUR 1.684 million. Through the implementation of the proposed scheme for the use of secondary products, a significant social effect is achieved by improving the environmental situation by reducing the amount of waste in the sludge collectors, creating jobs.

Characterization and pozzolanic properties of sewage sludge ashes (SSA) by electrical conductivity

Urbanization and continuing population and industrial growth have led to the intensification of management issues related to residues of wastewater treatment. To reduce sludge storage and carbon dioxide emissions resulting from Portland cement production, the pozzolanic activity of sewage sludge ash (SSA) was studied as a supplementary cementitious material (SCM). The SSAs that calcined in the temperature range of 600–900 °C were characterized by XRD, XRF, and laser diffraction. The pozzolanic reaction was monitored by an electrical conductivity measurement test, which demonstrated that the decrease in conductivity of an unsaturated pozzolan/calcium hydroxide suspension is correlated with the consumption of Ca(OH)2 during 1000 s. The results indicated that the calcination of sewage sludge at 600 °C is the most adequate for use as a pozzolan as it obtained a higher loss in conductivity (88.3%) and consumed less energy during the incineration process. A good correspondence was found between the mortar compressive strength test and the conductivity test, and both indicated that pozzolanicity decreases with temperature. Therefore, this method was found to be effective and hence can be used as a rapid and simple test for the pozzolanic activity evaluation of SSA.