Journal articles on the topic 'Sewage Purification Precipitation'
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1
Jin, La Hua, and Na Sha Jiang. "Research on Effect and Mechanism of Sewage Treatment by SBR with Concrete Bio-Films." Advanced Materials Research 726-731 (August 2013): 1930–34. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1930.
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In order to develop a new high-efficient but low-cost sewage treatment technology, sewage treatment experiments have been accomplished in a new type sequencing batch reactor with concrete bio-films. During experiments, simulation sewage was taken as raw water, and the operation sequence of the reactor was taken as 1.25h for water input and hypoxia, 1.25h for aeration, 0.5h for precipitation and 0.5h for water discharge successively. It has been shown by the experimental results that the reactor has optimal sewage purification effects, such as its average pollutant removal rate can arrive at about 95% for COD and BOD5, near 70% for ammonia hydrogen and about 40% for total phosphorus under the experimental condition. Main factors influencing the reactor purification effect have been discovered as pollutant volume load, ratio C/N, water temperature and amount of bio-films installed in the reactor. The mechanism of their influences has been also discussed in this paper.
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Andersson, C., M. Tendaj, and M. Rothman. "Filtration at Bromma Sewage Treatment Plant." Water Science and Technology 25, no. 4-5 (February 1, 1992): 59–66. http://dx.doi.org/10.2166/wst.1992.0481.
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The requirements for purification of the sewage will be more stringent in Sweden. For the three plants in Stockholm - Henriksdal, Bromma and Loudden the proposed limit concentrations for BOD7, total phosphorus and total nitrogen are 10, 0.3 and 15 respectively. A limit value of 0.3 mg/l of phosphorus in the effluent will require a filtration stage. In this paper results are presented from filter tests at Bromma sewage treatment plant. The tests were carried out during almost two years and included operation of different types of sand dual-media downflow filters and an upflow filter. The filters were tested with respect to sludge accumulation capacity, suspended solids removal and phosphorus removal at different operation conditions including chemical precipitation in the filters.
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Heinzmann, B. "Phosphorus recycling in sewage treatment plants with biological phosphorus removal." Water Science and Technology 52, no. 10-11 (November 1, 2005): 543–48. http://dx.doi.org/10.2166/wst.2005.0734.
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In this paper, phosphorus balances are calculated for the wastewater purification and sludge treatment stages for wastewater treatment plants (WWTPs) applying Enhanced Biological Phosphorus Removal (EBPR). The possible P-recovery potential is then estimated and evaluated regarding different locations along the process of wastewater purification and sludge treatment, taking the different phosphorus bonding forms into account. Caused by the more favourable bonding forms in the excess sludge as well as possibly also in the sludge ash a recovery of the phosphorus seems especially favoured for WWTPs with EBPR. The processes available for a P recycling are named, and special regard is given to the Phostrip-process, which is a possible recycling process already tested in practice. Further R&D demand consists in basic research regarding disintegration, fermentation or acidic total digestion of excess sludge followed by phosphorus precipitation including separation of the precipitates, MAP-precipitation and separation from digested sludge and on the ability to extract phosphorus and heavy metals from sewage sludge ash. These investigations are a precondition to enable purposeful process developments. At the present state the cost of recycled phosphorus earned from wastewater, sludge and ash, respectively, are a multiple higher than the costs for raw phosphate taking into account the suitable processes. Thus, up to now no phosphorus recycling with a defrayal of costs is possible. The future importance of phosphorus recycling will depend on the market price for raw phosphate, the recycling costs and, furthermore, on the general political framework.
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Yan, Min, Jian Zhang, Xiaoguo Wang, and Xin Lu. "Performance of a Tower-Shaped Integrated Ecological Purification Device for Pollutants Removal from Domestic Sewage in Rural Areas." International Journal of Environmental Research and Public Health 19, no. 24 (December 18, 2022): 17014. http://dx.doi.org/10.3390/ijerph192417014.
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With the continuous development of China’s modern economy and agricultural society, the discharge of rural sewage has been recognized as a major threat to the safety of the rural ecological environment. This study discussed the purification efficiency of a tower-shaped integrated ecological purification device (TIEPD)—consisting of a measuring tank, detention tank and three-stage purification unit—towards various common pollutants in rural areas during operation and tested the stability and efficiency of the TIEPD under different rural life events (fair activity days and nonfair activity days) and different precipitation intensities (light rain, moderate rain and heavy rain). The results showed that the average removal efficiencies of the TIEPD towards chemical oxygen demand, ammonia nitrogen, total nitrogen and total phosphorus were 69%, 67%, 54% and 73%, respectively. The average effluent concentration of each pollutant can meet the standard of the discharge of pollutants in China. The system exhibited good stability in removing pollutants and good ecological and economic benefits. This study provides the treatment of domestic sewage in the upper reaches of the Yangtze River and in mountainous areas of China and strengthens the prevention and control of rural nonpoint source pollution.
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Tsytlishvili, Kateryna. "Experimental Investigations of Removal of Phosphorus Compounds from Wastewater under Biological Purification." Key Engineering Materials 925 (July 11, 2022): 159–67. http://dx.doi.org/10.4028/p-p0fnoc.
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Today, most surface waters of Ukraine are eutrophied due to the entry into water bodies of a significant amount of nutrients – compounds of carbon, nitrogen and phosphorus. Nitrogen and phosphorus enter water bodies with wastewater, sewage from agricultural lands and livestock farms, as well as with precipitation, due to the decomposition of water biomass, aquatic vegetation and zoocenoses. In the presence of free carbon dioxide (the concentration of which depends on bicarbonate alkalinity and water pH) and at certain rates of biochemical oxygen utilization (BOD) 7.2 g of nitrogen and 1 g of phosphorus produce 115 g of algae, which decomposition then consumes 115 g of oxygen [1].
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Baldi, Marco, Andrea Martinotti, Sabrina Sorlini, Ioannis Katsoyiannis, Alessandro Abbà, Marco Carnevale Miino, and Maria Collivignarelli. "Extraction and Purification of Phosphorus from the Ashes of Incinerated Biological Sewage Sludge." Water 13, no. 8 (April 16, 2021): 1102. http://dx.doi.org/10.3390/w13081102.
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Phosphorus depletion represents a significant problem. Ash of incinerated biological sewage sludge (BSS) contains P, but the presence of heavy metals (e.g., Fe and Al) is the main issue. Based on chemical characterization by SEM-EDS, ED-XRF and ICP-OES techniques, the characteristics and P content of bottom ash (BA) and fly ash (FA) of incinerated BSS were very similar. On BA, P extraction carried out in counter- current with an S:L ratio of 1:10 and H2SO4 0.5 M led to better extraction yields than those of a similar test with H2SO4 1 M and an S:L ratio of 1:5 (93% vs. 86%). Comparing yields with H2SO4 0.5 M (S:L ratio of 1:10), the counter-current method gave better results than those of the crossflow method (93% vs. 83.9%), also improving the performance obtained with HCl in crossflow (93% vs. 89.3%). The results suggest that the purification of the acid extract from heavy metals with pH variation was impractical due to metal precipitation as phosphates. Extraction with H2SO4 and subsequent treatment with isoamyl alcohol represented the best option to extract and purify P, leading to 81% extraction yields of P with low amounts of metals.
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Ke, F., W. C. Li, H. Y. Li, F. Xiong, and A. N. Zhao. "Advanced phosphorus removal for secondary effluent using a natural treatment system." Water Science and Technology 65, no. 8 (April 1, 2012): 1412–19. http://dx.doi.org/10.2166/wst.2012.003.
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Mechanisms for low concentrations phosphorus removal in secondary effluent were studied, and a process was developed using limestone filters (LF), submerged macrophyte oxidation ponds (SMOPs) and a subsurface vertical flow wetland (SVFW). Pilot scale experimental models were applied in series to investigate the advanced purification of total phosphorus (TP) in secondary effluent at the Chengjiang sewage treatment plant. With a total hydraulic residence time (HRT) of 82.52 h, the average effluent TP dropped to 0.17 mg L−1, meeting the standard for Class III surface waters. The major functions of the LF were adsorption and forced precipitation, with a particulate phosphorus (PP) removal of 82.93% and a total dissolved phosphorus (TDP) removal of 41.07%. Oxygen-releasing submerged macrophytes in the SMOPs resulted in maximum dissolved oxygen (DO) and pH values of 11.55 mg L−1 and 8.10, respectively. This regime provided suitable conditions for chemical precipitation of TDP, which was reduced by a further 39.29%. In the SVFW, TDP was further reduced, and the TP removal in the final effluent reached 85.08%.
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Volkova, V. N., S. V. Kundenok, and V. L. Golovin. "Improving the Efficiency of Sewage Treatment Plants on the Example of Treatment Plants in the Cities of Artem and Vladivostok." IOP Conference Series: Earth and Environmental Science 988, no. 4 (February 1, 2022): 042055. http://dx.doi.org/10.1088/1755-1315/988/4/042055.
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Abstract Fugate water, when it enters the beginning of sewage treatment plants (STP), increases the load on the biological treatment system. Methods of purification of the STP return water are considered. A new composite composition has been developed for the reagent precipitation of ammonium and phosphates from water, which is formed as a result of thickening and dewatering of sludge. On the basis of the experimental data obtained, a technological scheme for the treatment of water formed after mechanical dewatering of excess activated sludge and sludge from the operation of treatment plants at biological wastewater treatment plants has been developed. The developed technological solution makes it possible to exclude the effect of aluminum on activated sludge and minimize the negative effect of ammonium and phosphates, with minimal construction and operating costs. The proposed cleaning method is applicable to both existing treatment facilities and newly designed ones.
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Liang, Sha, Haoming Chen, Xiaohui Zeng, Zhibin Li, Wenbo Yu, Keke Xiao, Jingping Hu, et al. "A comparison between sulfuric acid and oxalic acid leaching with subsequent purification and precipitation for phosphorus recovery from sewage sludge incineration ash." Water Research 159 (August 2019): 242–51. http://dx.doi.org/10.1016/j.watres.2019.05.022.
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Hryhorenko, L. V. "Ecological and Hygienic Estimation Precipitation of the Municipal Wastewater Application at the Formation of Secondary Ecosystems in the Mining and Iron Ore Processing Areas." Advanced Engineering Forum 20 (January 2017): 61–67. http://dx.doi.org/10.4028/www.scientific.net/aef.20.61.
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On the basis of Krivoy Rog iron mining ore deposit companies (Ukraine) the complex field studies focused on the fast development of secondary landscapes in the surface of dumps after iron mining were carried out. In order to create the top layer of waste purification from household sewage was carried out sewage clearing facility silt. It is well known that breed dumps are dangerous for the environment, particularly for the surface and ground water. Overnormal concentrations of salt had been found in water samples, taken from the river Inhulets in a zone of influence breed (2.1 MPL), sulfates and carbonates (2.7 MPL), iron (2.1 MPL), chloride (1.7 MPL), magnesium (3.1 MPL). In the wells from nearest villages water is not suitable for drinking purposes and contains total sum of salts – 4.97 MPL, sulfates and carbonates – 5.16 MPL, cadmium – 3.7 MPL, lead – 1.53 MPL. Thus, the toxic heavy metals concentrations (Pb, Cd, Zn, Mn, Cu, Cr, Ni, Fe) in the fish and amphibians, as well as herbaceous plants in these areas did not exceed the permissible levels.Use of clearing facilities sludge aged from 1.5 years and more in the amount 15 kg/m2 did not lead to increased concentration of heavy metals in the top layer of dumps. Total pollution of the soil within six months after application of sludge correspond to the "permissible" level (Zc = 1.61).To assess the suitability of the silt dumps, we proposed list of indicators, which correspond to the chemical and epidemiological safety and classify as "suitable", "conditionally suitable" and "not suitable". We found that optimal conditions for formation of a new soil dumps with ratio of such indicators as "nitrogen: phosphorus: potassium" should be corresponded to the working dose 300 kg/ha by nitrogen amount. This is the maximum amount of mature silt 66.7-70 ton/ha.
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Green, David H., and Gillian D. Lewis. "Enzymatic amplification of enteric viruses from wastewaters." Water Science and Technology 31, no. 5-6 (March 1, 1995): 329–36. http://dx.doi.org/10.2166/wst.1995.0636.
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The challenge to use of enzymatic amplification for detection of waterborne viruses is the effective removal of a range of inhibitory components present in environmental samples. This study combines a number of individual processes to simultaneously concentrate and purify enteric viruses from wastewaters. The procedure of secondary concentration and purification, using chloroform extraction, polyethylene glycol precipitation, Sephadex G-200 gel filtration, and ultrafiltration, was shown to be 39 and 31% efficient in recovering enterovirus from raw sewage and oxidation pond effluent respectively, achieving a 100-fold reduction of the sample volume from 10 mL to 100 μL. The secondary concentrates were analysed by reverse transcription and polymerase chain reaction, and the sensitivity was shown to be between 0.02-0.2 plaque forming units of enterovirus. This allows the theoretical detection of approximately 1 PFU/L of wastewater. The Tth polymerase was shown to be more effective for the amplification of virus in wastewaters than was Taq polymerase. Overall, the procedure enabled the sensitive detection of rotavirus, hepatitis A, and enterovirus from wastewaters.
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Zacharias, N., S. M. Essert, A. F. Brunsch, E. Christoffels, T. Kistemann, and C. Schreiber. "Performance of retention soil filters for the reduction of hygienically-relevant microorganisms in combined sewage overflow and treated wastewater." Water Science and Technology 81, no. 3 (February 1, 2020): 535–43. http://dx.doi.org/10.2166/wst.2020.132.
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Abstract Environmental quality standards for surface waters have been significantly expanded through recent amendments to German regulations. Limit values are only established for applicable regulations if the water is indicated for certain uses, e.g. abstraction of irrigation water. Nevertheless, surface water bodies are often used for hygiene-sensitive purposes. In the course of climate change, stronger precipitation events will occur, which may lead to more frequent loading and discharge of combined sewer overflow (CSO) into surface water bodies. Retention soil filters (RSFs) are attracting attention as an extensive treatment technology for CSO and additional wastewater treatment. This study examined large-scale RSFs for CSO treatment, as well as the effectiveness of RSFs as a fourth purification stage. An RSF test facility was established at a municipal wastewater treatment plant (WWTP), consisting three semi-technical RSFs that were fed exclusively with treated water from the WWTP. The reduction of microorganisms mostly occurred within the first centimeters of the RSFs. For most hygienic-microbiological parameters, a 1–2 log unit reduction could be detected in addition to the reduction within the WWTP. Antibiotic-resistant bacteria were reduced to the same extent. Investigation of the large-scale RSFs showed that a flow rate reduced by half corresponded to better reduction performances.
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Magalhães, M. Clara F. "Arsenic. An environmental problem limited by solubility." Pure and Applied Chemistry 74, no. 10 (January 1, 2002): 1843–50. http://dx.doi.org/10.1351/pac200274101843.
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Arsenic is a toxic element for animals and the majority of plants, in spite of evidence that it is also an essential element. The long-term intake of small doses of arsenic has a carcinogenic effect. There are well-identified regions where arsenic ground water concen- trations can reach values higher than 2 mg/L. Water purification and waste treatment techniques based on (1) precipitation of calcium, magnesium, and iron(III) arsenates, and/or (2) adsorption or coprecipitation of arsenic oxyanions are unlikely to produce aqueous solutions with arsenic concentrations below the guideline values proposed for arsenic dissolved in potable water and treated sewage effluents. As(III) species are more toxic than As(V) species. Arsenate species are predominant at moderate and high redox potentials, while arsenite species occur under more reducing conditions. Metal arsenites are much more soluble than the corresponding metal arsenates, and arsenites are adsorbed less by solid phases. Remediation techniques must consider the available information on solubility and adsorptive properties of As(III) and As(V). The less-soluble lead and barium arsenates are not suitable for arsenic decontamination. New remediation methods must consider solubility data for arsenic-containing materials and minerals.
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Hultgren, J., L. G. Reinius, and M. Tendaj. "Upgrading of the Treatment Plants in Stockholm to Meet More Stringent Requirements." Water Science and Technology 22, no. 7-8 (July 1, 1990): 77–84. http://dx.doi.org/10.2166/wst.1990.0232.
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The purification requirements for the Stockholm sewage treatment plants will become more stringent in the future. The expected limit values for the effluent, expressed as annual mean values, are for BOD7, Tot-P, and Tot-N, 10, 0.3 and 15 mg/l respectively. If these contents are multiplied by the design flow values for the three plants, we obtain the maximum quantities which may be released. If the relevant authorities permit the municipality to distribute these total quantities as desired between the three plants, future necessary extensions can be optimized. The following main principles apply to an extension of the three plants: Loudden sewage treatment plant: This comparatively small treatment plant could, if the requirements are lower than in the other two plants, continue in operation with no other extensions than the inclusion of anoxic zones. It would, however, be necessary to refurbish the plant after a number of years of neglected maintenance. Bromma sewage treatment plant: The biological stage was extended during the 1982-84 period. For this reason, the municipality suggests that no further extensions of the aeration tanks be required, before 1995 at the earliest. A nitrogen removal with outgoing contents of Tot-N of 15-17 mg/l is expected to be achieved by measures taken to reduce the load on the biological stage instead. These measures consist of centrifuging the excess sludge and pumping it directly to the digesters instead of returning it to the inlet. Furthermore, separate treatment of the reject water from the sludge centrifuges is planned. A third measure could be changing over to a more efficient precipitation chemical to permit a further reduction of the load on the biological stage with regard to, inter alia, BOD7, Tot-N etc. To meet the requirements for phosphorus removal (0.3 mg/l), the plant will be extended with a filter stage after the existing biological stage. Henriksdal sewage treatment plant: At this plant, which is the largest of the three, the largest extensions are planned. To meet the requirements for nitrogen removal, the present volumes in the aeration tanks will be tripled and will be utilized as anoxic and aerated zones as required. Three new lines with aeration tanks and secondary sedimentation tanks will be constructed. The existing aeration tanks will also be deepened from 5 to 12 m. The requirements for low phosphorus contents in the effluent will be met by installing a filter stage, as in the Bromma plant.
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Amonova, Matluba M., and Kazokmurod A. Ravshanov. "POLYMERIC COMPOSITION FOR PURIFICATION OF WASTEWATER FROM VARIOUS IMPURITIES IN TEXTILE INDUSTRY." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 10 (October 29, 2019): 147–53. http://dx.doi.org/10.6060/ivkkt.20196210.5963.
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This article deals with the development of new and improvement of traditional methods of wastewater treatment of dyening and finishing industries. The composition was developed on the basis of local natural minerals (bentonite Navahermosa origin, sodium bisulfite, polyacrylamide and aluminium sulphate) for the treatment of wastewater of the textile industry. The influence of bentonite particle size on the degree of wastewater discoloration at different flow rates was studied. With a range of wastewater supply flow rates from 0.5 to 2.0 m/s with a particle size of bentonite adsorbent in the range of 0.25-1.0 nm, the maximum degree of wastewater bleaching is achieved and it is in the range of 84-87%. For microporous adsorbents (CAD-100 and CAD-200) the effectiveness of the discoloration also does not depend on the particle size and ranges from 85 to 87 %. It was found that, for fine-pored adsorbents (BKA-100 and BKA-200), the efficiency of discoloration also practically does not depend on the particle size and ranges from 85 to 87 %. The highest degree of wastewater treatment according to the proposed composition, apparently due to the fact that in the adsorption process, in addition to the sorption of sewage impurities on the surface of adsorbents, there is a sorption of ions and molecules of dissolved substances on the surfaces of air bubbles and their removal in the foam layer. The wastewater treatment parameters of the dyeing and finishing shop using the bentonite composite adsorbent show that the degree of removal of contaminants by the method developed by us is much higher compared to the sedimentation of aluminum or iron oxyhydrates with adsorbed contaminants. Moreover, the effects of reducing the value of COD and concentration of the surfactant in the wastewater was, on average, 65 % and 82 %, and compared to the effects of reducing the same parameters at defending precipitation of oxyhydrates at 48-54 % and 54-61 %, respectively.
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Londong, Jörg, and Stefan Zander. "Steps in Planning the Expansion of the Large Sewage Treatment Plant at Buchenhofen, Operated by the Wupper Watershed Management Association." Water Science and Technology 22, no. 7-8 (July 1, 1990): 123–29. http://dx.doi.org/10.2166/wst.1990.0237.
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Sewage from 700,000 PE, roughly half of which is discharged by industry, is treated at the Buchenhofen plant operated by the WWMA, using a conventional, activated-sludge process without specific nutrient elimination. A draft management plan has been prepared for the receiving stream of the treatment plant, the Lower Wupper. The chief forms of use for the waters are fixed in binding agreements. The use entailing the strictest limiting values is recreational fishing, which demands surface water quality class II. Very substantial demands, which must be regarded as at least equivalent to state-of-the-art technology, are imposed on the Buchenhofen facility. The Institut für Siedlungswasserbau, Wassergütewirtschaft und Abfalltechnik at the University of Stuttgart was commissioned to formulate realistic purification objectives for the treatment plant and to prepare expansion concepts. At Buchenhofen, the single-stage activated sludge process with nitrification and preliminary de-nitrification has proved to be the most effective method for eliminating nitrogen while simultaneous precipitation followed by flocculation-filtration is the best process for eliminating phosphorus. For purely scientific reasons, however, the extreme demands in terms of ammonium and nitrite rule out expansion of a treatment plant of this size. The proposed designs therefore require validation through commercial-scale testing. Only after a 6- to 12-month test series has been evaluated will a draft design be prepared for approval, ultimately enabling the plant to be expanded and to fulfil the management planning objective of achieving surface water quality class II in the Wupper.
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Nyberg, U., H. Aspegren, B. Andersson, J. la C. Jansen, and I. S. Villadsen. "Full-Scale Application of Nitrogen Removal with Methanol as Carbon Source." Water Science and Technology 26, no. 5-6 (September 1, 1992): 1077–86. http://dx.doi.org/10.2166/wst.1992.0549.
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In Sweden many advanced sewage treatment plants for BOD and phosphorus removal have to be extended with nitrogen removal. Due to existing plant configuration and wastewater composition, denitrification with supply of an external carbon source can be a cost-effective solution in many cases. At the Klagshamn wastewater treatment plant in Malmo investigations for extensive nitrogen removal have been made in a single-sludge system with pre-precipitation and post-denitrification where methanol was added for denitrification. Results from the tests showed that a high level of nitrogen removal can be reached, and that the process was stable and easy to operate. The process application gave less supplementary cost for an extended nitrogen removal than for upgrading the plant with larger basin volumes. In order to examine the purification performance caused by the addition of methanol, the starting period was followed extensively with online nitrate sensors and daily composite samples. The development of the denitrif ication capacity of the sludge with methanol and acetate as carbon sources was followed and microbiological changes were examined microscopically. Complete denitrification was obtained after approximately one month at 10°C. The denitrification capacity of the sludge with methanol reached that of acetate after about the same time. The microscopic examination revealed a growing population of budding and/or appendaged bacteria, presumably Hyphomicrobium spp, reaching a stable maximum at the time when optimal nitrate removal occurred.
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Zhytsianiou, Barys N., and Lyudmila E. Yordanova. "Backwash water treatment by coagulation in the presence of phosphates at underground water iron removal stations." Vestnik MGSU, no. 4 (April 2020): 553–68. http://dx.doi.org/10.22227/1997-0935.2020.4.553-568.
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Introduction. The analysis of the present-day condition of water resources has proven the relevance and expediency of developing highly effective backwash water treatment methods to be used at iron removal stations designated for groundwater treatment. In accordance with effective technical regulations, backwash water must be reused. The operation of iron removal stations has proven the inefficiency of backwash water treatment facilities. Water and wastewater treatment companies stop using backwash water treatment facilities and refrain from reusing backwash water. Highly concentrated iron-bearing backwash water is discharged into sewage networks, nearby water bodies or onto the terrain, which means irrational use of high-quality groundwater and environmental pollution with iron compounds.
Materials and methods. The results of experimental research efforts and statistical processing of data on the qualitative and quantitative composition of backwash water at iron removal stations are presented. The chemical nature of the components and the principle underlying the formation of the backwash water composition in the process of groundwater deferrization have been studied. It’s been identified that if backwash water supplied by iron removal stations is treated by sodium phosphate reagent Na3PO4 and aluminum sulphate Al2(SO4)3 as a coagulant, precipitation of iron compounds intensifies, as colloidal particles FePO4 are formed. They have very low solubility, and they are effectively removed by coagulation. It has been theoretically proven and experimentally confirmed that anions H2 PO4– and PO4 3– fformed in the process of hydrolysis of sodium phosphate Na3PO4 help to reduce the electrokinetic charge of the colloidal particle of iron hydroxide Fe(OH)3, and high purification efficiency reaching 99.0–99.9 % is attained by attaching iron compounds to the surface of the colloidal particle of aluminum hydroxide Al(OH)3.
Conclusions. The co-authors have developed a math-and-stats model simulating the backwash water treatment process that employs coagulation in the presence of phosphates. It describes the dependence between the concentration of residual iron, doses of sodium phosphate Na3PO4, aluminum sulphate Al2(SO4)3 and the settling time. A backwash water treatment technology has been developed. It employs coagulation in the presence of phosphates, and it is designated for use at iron removal stations. This technology comprises a chemical plant for sodium phosphate and aluminum sulphate used as a coagulant, a post-treatment filter, and sludge dewatering facilities. The application of this technology enables to reduce iron concentration to 0.05–0.20 mg/l, to reuse backwash water for drinking and other household purposes, or to have this water reused by iron removal stations, this, preventing pollution of water sources with iron compounds.
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Каверина, Наталия Викторовна. "STATE OF BOTTOM SEDIMENTS OF THE VORONEZH RESERVOIR IN THE PLACES OF WATER DISCHARGE FROM THE TREATMENT FACILITIES OF THE CITY OF VORONEZH." Housing and utilities infrastructure, no. 4(19) (December 22, 2021): 77–84. http://dx.doi.org/10.36622/vstu.2021.19.4.008.
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Рассмотрена проблема загрязнения Воронежского водохранилища в пределах Воронежской городской агломерации, в местах сброса вод с очистных сооружений предприятий левого берега. В работе использованы результаты количественного химического анализа донных отложений, выполненных на базе эколого-аналитической лаборатории факультета географии, геоэкологии и туризма Воронежского госуниверситета, а также данные мониторинга, предоставленных Федеральной службой по надзору в сфере природопользования и Департаментом природных ресурсов и экологии Воронежской области. База данных включает результаты наблюдений с 2000 по 2021 год. По составу осадков прослежена история аккумуляции загрязнителей, выделены проблемные зоны водоема в каждом исследуемом периоде. Выполнен пространственно-временной анализ содержаний загрязняющих веществ, рассчитаны «кларки концентрации» тяжелых металлов, по которым для каждой точки наблюдения в порядке возрастания значения признака построен ранжированный ряд. На основании лабораторных исследований и результатов их статистической обработки с применением корреляционного анализа сделаны выводы о перспективах существования и развития Воронежского водохранилища. Проверены корреляционные связи между «кларками концентрации» и суммой выпавших осадков за календарный и за гидрологический год. По содержаниям сероводорода в различные годы, сделаны выводы о диапазоне колебания концентраций и формировании цикличного процесса. Выделена зона устойчивой деградации водоема. Ее формирование происходит выше и ниже сброса с городских очистных сооружений левого берега города. Результаты многолетних наблюдений за качеством донных отложений указывают на значительную техногенную нагрузку со стороны Воронежской городской агломерации. Недостаточная очистка воды, медленная скорость течения и турбулентность природной воды ускоряет процесс естественного эвтрофирования водоема. The author considers the problem of pollution of the Voronezh water reservoir within the Voronezh urban agglomeration, in places of discharge of water from the treatment facilities of enterprises of the left bank. The paper uses the results of quantitative chemical analysis of bottom sediments performed on the basis of the ecological and analytical laboratory of the Faculty of Geography, Geoecology and Tourism of Voronezh State University, as well as monitoring data provided by the Federal Service for Supervision of Nature Management and the Department of Natural Resources and Ecology of the Voronezh Region. The database includes the results of monitoring from 2000 till 2021. On the basis of the composition of precipitation the author detected the history of accumulation of pollutants; as well she identified problem areas of the water reservoir in every study period. The author performed a spatio-temporal analysis of the contents of pollutants, calculated the "concentration clarkes" of heavy metals, according to which she created an ordered series for each observation point in ascending order of the attribute value. Based on laboratory studies and results of their statistical processing using correlation analysis the author draws some conclusions concerning the prospects for the Voronezh water reservoir existence and development. The correlations between the "concentration clarkes" and the amount of precipitation for the calendar and hydrological year have been verified. Based on the hydrogen sulfide content in different years, the author concludes about the range of concentration fluctuations and the formation of a cyclic process. She identified the zone of stable degradation of the water reservoir. Its formation occurs above and below the discharge from the municipal sewage treatment plants of the left bank of the city. The results of long-term observations of the quality of bottom sediments indicate a significant anthropogenic load on the part of the Voronezh urban agglomeration. Insufficient water purification, slow flow velocity and turbulence of natural water accelerate the process of natural eutrophication of the water reservoir.
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Šperac, Marija, and Dino Obradović. "PARAMETERS OF INTEREST FOR THE DESIGN OF GREEN INFRASTRUCTURE." Journal of Urban and Environmental Engineering, October 5, 2019, 92–101. http://dx.doi.org/10.4090/juee.2019.v13n1.092101.
Full textAbstract:
The urbanization process significantly reduced the permeability of land surfaces, which affected the changes of runoff characteristics and the relations in the hydrological cycle. In urban environments, the relationships within the hydrological cycle have changed in quantity, in particular: precipitation, air temperature, evaporation, and infiltration. By applying the green infrastructure (GI) to urban environments is beneficial for the water resources and the social community. GI has an effect on the improvement of ecological, economic, and social conditions. Using GI into urban areas increases the permeability of land surfaces, whereby decreasing surface runoff, and thus the frequency of urban floods. It also has a significant influence on the regulation of air quality, water purification, climate change impact, and the changes in the appearance of the urban environment. When planning and designing the GI, it is necessary to identify the type of GI and determine the size and location of the selected GI. Since each urban environment has its own characteristics, it is necessary to analyze them before deciding on the GI. The paper analyzed meteorological parameters (precipitation, air temperature, insolation, air humidity) affecting the selection of GI types, using the specific example of an urban environment – the City of Osijek, Croatia. Significant parameters when designing GI are operation and maintenance These parameters directly affect the efficiency of GI. The proper selection of GI and its location results in maximum gains: the reduction of land surface drainage - drainage of the sewage system, purification and retention of precipitation at the place of production, the improvement of air quality, and the improvement of living conditions in urban environments
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Heinzmann, Bernd, and Gerd Engel. "Induced Magnesium Ammonia Phosphate Precipitation to Prevent Incrustations and Measures for Phosphorus Recovery." Water Practice and Technology 1, no. 3 (September 1, 2006). http://dx.doi.org/10.2166/wpt.2006.051.
Full textAbstract:
In 1994 for the first time massive incrustations in the centrifuges treating the digested sludge were detected in some wastewater treatment plants (WWTP’s) of the Berliner Wasserbetriebe, which were, as was found out later, mainly due to the precipitation of white MAP (magnesium ammonium phosphate = struvite) deposits with small portions of different calcium phosphate compounds. The reason for this was the over saturation of the digested sludge and the process water (from the separated centrate of the digested sludge) with carbon dioxide, the spontaneous release of or degassing of carbon dioxide, causing the pH to increase, thus altering the solubility equilibrium, and facilitating crystallisation, resulting in deposits (incrustations) on the walls. Obviously, the wastewater purification process used, with enhanced biological phosphorus removal and concentrated streams of digesting sludge, favours the formation of incrustations during sludge treatment. These incrustations were the cause of a lot of operational problems. To prevent incrustations, modifications in the process engineering technology have been applied after several studies and trials. Deliberate extraction of the CO2, e.g. by air injection through a fine-bubble surface aeration system at the bottom of the digested sludge storage tank just before the centrifuges, causes the pH to rise to approx. 8 and thus to cause induced struvite precipitation. This technology enables a precipitation product suitable for recycling to be generated and separated from the anaerobic sludge using a hydro-cyclone. A subsequent second hydro-cyclone stage allowed a further increase in the P-concentration to approx. 40 kg/m3, giving a yield of phosphorus of 20 %. This corresponds with P-load of approx. 316 kg/day and amounts to 18 % of the P inlet load in the WWTP Waßmannsdorf. It was shown that this experimental process is in principle suitable for the separation of the MAP precipitation product in the anaerobic sludge. A complete washing process for the raw MAP is not yet installed, and furthermore, to find the best sizes of nozzles in the hydro-cyclones and most effective pressures tests will have to be carried out soon at pilot level. A comparison with the minimum nutrients content for different kinds of fertiliser (super-phosphate, dicalcium-phosphate with magnesium, NP-fertiliser) defined by the German Fertiliser Regulations, shows that the precipitated MAP is within the range of other legally certified fertilisers. The MAP showed contaminant levels 5 times or more below the limit values of the German Sewage Sludge Ordinance. The MAP precipitation product is very soluble in different solvents (from ammonium chloride to hydrochloric acid). This implies that the precipitation product can be used as a long term fertilizer. In two test soils having a pH value of 6.6 and 7.1, the MAP precipitation solid was tested using standard ryegrass and showed good phosphorus availability from this material leading to a good grass growth.
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Koduru, Lakshmi Prasanna. "Magnetic Graphene Oxide Composites are the Solutions for Sustainable Remediation of Ecosystems." Environmental Analysis & Ecology Studies 2, no. 1 (April 3, 2018). http://dx.doi.org/10.31031/eaes.2018.02.000528.
Full textAbstract:
Heavy metals are one of the primary contaminants in the environment [1]. Exposure to heavy metals, even at trace levels, is believed to be a high health risk for humans [2,3]. Heavy metals are naturally occurring throughout the earth’s crust [4]. But most of the environmental contamination results from the anthropogenic activities such as mining and smelting operations, industry, and domestic and agricultural use of metals and metalcontaining compounds. Migration of these contaminants into non-contaminated areas as dust or leachates through the soil and spreading of heavy metals containing sewage sludge are a few examples of events contributing towards contamination of the ecosystems [5]. Hence, water is the one of the major routes through which heavy metals and radionuclides may enter the human body [6,7]. The sources of water pollution are shown in Figure 1. The conventional wastewater purification techniques including chemical coagulation, photo degradation, precipitation, flocculation, activated sludge, membrane separation and ion exchange are limited to the removal of heavy metals at trace levels [7-9]. However, adsorption is one of the best methods for the purification of water, owing to its low cost and easy handling of materials [7,10-12]. Moreover, adsorption approaches using commercial activated carbon, micro-filtration and membrane techniques are effective, but their use is limited by the complicated installation process involved coupled with the high maintenance costs of the systems [7,13]. Hence, these drawbacks have necessitated the search for an alternative method which is inexpensive, renewable and cost-effective for the removal of heavy metals from aqueous solutions. Many scientific groups have prepared graphene or graphene oxide (GO) based hybrid nanocomposites for various potential applications [14-17]. The study of literature survey and stability of the GO-based nanocomposites prompted us to survey on graphene oxide and reduced graphene oxide-based inverse spinel nickel ferrite nanocomposites for the removal of heavy metals and radionuclides from water with the purpose of reducing their environmental impact
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Koduru, Lakshmi Prasanna. "Magnetic Graphene Oxide Composites are the Solutions for Sustainable Remediation of Ecosystems." Environmental Analysis & Ecology Studies 2, no. 1 (April 3, 2018). http://dx.doi.org/10.31031/eaes.2018.02.000528.
Full textAbstract:
Heavy metals are one of the primary contaminants in the environment [1]. Exposure to heavy metals, even at trace levels, is believed to be a high health risk for humans [2,3]. Heavy metals are naturally occurring throughout the earth’s crust [4]. But most of the environmental contamination results from the anthropogenic activities such as mining and smelting operations, industry, and domestic and agricultural use of metals and metalcontaining compounds. Migration of these contaminants into non-contaminated areas as dust or leachates through the soil and spreading of heavy metals containing sewage sludge are a few examples of events contributing towards contamination of the ecosystems [5]. Hence, water is the one of the major routes through which heavy metals and radionuclides may enter the human body [6,7]. The sources of water pollution are shown in Figure 1. The conventional wastewater purification techniques including chemical coagulation, photo degradation, precipitation, flocculation, activated sludge, membrane separation and ion exchange are limited to the removal of heavy metals at trace levels [7-9]. However, adsorption is one of the best methods for the purification of water, owing to its low cost and easy handling of materials [7,10-12]. Moreover, adsorption approaches using commercial activated carbon, micro-filtration and membrane techniques are effective, but their use is limited by the complicated installation process involved coupled with the high maintenance costs of the systems [7,13]. Hence, these drawbacks have necessitated the search for an alternative method which is inexpensive, renewable and cost-effective for the removal of heavy metals from aqueous solutions. Many scientific groups have prepared graphene or graphene oxide (GO) based hybrid nanocomposites for various potential applications [14-17]. The study of literature survey and stability of the GO-based nanocomposites prompted us to survey on graphene oxide and reduced graphene oxide-based inverse spinel nickel ferrite nanocomposites for the removal of heavy metals and radionuclides from water with the purpose of reducing their environmental impact