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Статті в журналах з теми "Sewerage Purification Biological treatment"
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Bischof, Franz, Wolfgang Schulz, Ralph Teckenberg, and Peter Nitsch. "Increase of purification capacity in small treatment units." Water Science and Technology 33, no. 10-11 (May 1, 1996): 161–70. http://dx.doi.org/10.2166/wst.1996.0672.
Повний текст джерелаАнотація:
Especially in rural regions most of the costs for wastewater treatment arise from the sewerage system due to the long distances between the different smaller communities and the centralized treatment station. Meanwhile, there are a lot of different systems available for smaller communities like trickling filter systems or activated sludge treatment systems, respectivly. In general, these smaller treatment units can fulfill the demands for the purification efficiency given by the law. But especially in the range of about 200 to 1000 population equivalents there are hardly any systems known which can serve for a controlled denitrification process. Normally two single, locally distinguishable, basins are erected to allow for the biological demands of the denitrification process. This results in pumping an enormous amount of wastewater with dissolved nitrate within the treatment station, the so-called internal recirculation. In this paper, a novel reactor is described where the nitrification zone was set above the denitrification zone in one tank. Both regions are separated by an intermediate bottom. Stirring and aeration in the different zones are carried out simultaneously by two different-sized hyperboloid stirrers. The paper will give an introduction in the working principle of this novel system which was developed for community sizes lower than 1000 population equivalents. It can demonstrate the visualization of the flow field and the exchange of water between the two different zones.
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Merchán-Sanmartín, Bethy, Maribel Aguilar-Aguilar, Fernando Morante-Carballo, Paúl Carrión-Mero, Jaime Guambaña-Palma, Diego Mestanza-Solano, and Edgar Berrezueta. "Design of Sewerage System and Wastewater Treatment in a Rural Sector: A Case Study." International Journal of Sustainable Development and Planning 17, no. 1 (February 28, 2022): 51–61. http://dx.doi.org/10.18280/ijsdp.170105.
Повний текст джерелаАнотація:
The accelerated growth of the population in recent years presents, as a great consequence, a significant increase in wastewater, which, on many occasions, is not discharged properly. This work aims to design a sewerage and wastewater treatment system in Las Mercedes commune in southern Ecuador based on geological, topographic, hydrological, geochemical and demographic parameters. All this focused on reducing pollution and complying with current national and international regulations, meeting the needs of the rural population studied. The methodology used consists of four phases: i) collection, inventory and processing of the base information ii) design of the sewerage system, ii) design of a wastewater treatment system and iv) environmental impact assessment and referential budget. The sewerage system consists of 3.2 km long PVC pipes that transport wastewater to a purification system of water pretreatment and facultative and maturation ponds. The designed system complies with a total purification of 636.27 MPN/100 ml of faecal coliforms (99.994%) and 35.30 mg/l of BOD5 (88%). The proposed design contributes to wastewater management and environmental education research, defining a combined model of a sewerage system with stabilisation ponds replicable in communities with similar conditions.
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Bortenschlager, Peter. "The Vienna Sewerage System." Water Science and Technology 22, no. 5 (May 1, 1990): 235–40. http://dx.doi.org/10.2166/wst.1990.0034.
Повний текст джерелаАнотація:
After the practice for many decades had been to introduce waste waters into the nearest receiving bodies, i.e. Wien River, Donaukanal, and Danube, a multitude of intercepting sewers and a central treatment plant were built from 1969 to 1980. Subsumed under the working title “WABAS 80 -- Wiener Abwasserbeseitigungssysteme 1980”, these facilities guaranteed that all effluent produced in Vienna was brought to the central treatment plant for purification. Since 1986 a programme has been in effect to expand the existing sewage system and improve obsolete sewers, the aim being to preserve groundwater quality. Providing also for the construction of relief interceptors along the Donaukanal and the Wien River as well as the enlargement of the central treatment plant, the programme was designed not only to preserve but also to improve water quality in the Donaukanal and the Danube itself. The City has set apart AS 12 000 million for this project, which is to be completed by 2000.
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Chipiga, L. A., A. V. Vodovatov, I. A. Zvonova, A. A. Stanzhevsky, A. V. Petryakova, E. E. Anokina, K. S. Velichkina, and S. A. Ryzhov. "Management of biological waste of patients after radionuclide therapy." Radiatsionnaya Gygiena = Radiation Hygiene 15, no. 2 (June 25, 2022): 19–30. http://dx.doi.org/10.21514/1998-426x-2022-15-2-19-30.
Повний текст джерелаАнотація:
Radioactive waste management is a modern-day issue in terms of radiation safety due to the development of radionuclide therapy, the emergence of new radiopharmaceuticals, radionuclides, and treatment methods, which allow for radionuclide therapy in a day hospital. According to the current domestic regulatory and methodological support biological wastes generated during the patient’s metabolic activity after injection of the radiopharmaceuticals for the therapy refer to the liquid radioactive waste. These wastes must be collected and kept for decay in hospitals to the safe levels before being spilled into the municipal sewerage. It requires additional expenses to the hospital for making the special sewerage. To increase the availability of radionuclide therapy, it is necessary to update the requirements of the liquid radioactive waste management in nuclear medicine departments, considering the volume activities of different diagnostic and therapeutic radionuclides in wastes generated after the injection of radiopharmaceuticals to the patients. On the basis of findings, it is possible to evaluate the feasibility of the binding requirement for the availability of special sewerage in the departments of the radionuclide therapy. In this work, excretion of the radiopharmaceuticals used in therapy: 89Sr-dichloride, 223Ra-dichloride, 131I-MIBG, 177Lu-PSMA, and 225Ac-PSMA was studied based on published data to determine the activity levels of radionuclides in waste of patients. As a results of preliminary computations, some nuclear medicine procedure will not lead to generation of liquid radioactive waste from biological waste of patients in sewerage system in usual operating condition and special sewerage is not strictly necessary. For example, estimations of radionuclide activity in wastes showed the volume of current sewerage system in a small hospital with a limitation of 50 beds can be enough to reduce the level of specific activity of radionuclides in wastewater from one patient a day after radionuclide therapy with 89Sr-chloride and 223Ra-dichloride. In order to revision of requirements to special sewerage in each department of radionuclide therapy and to development of differentiated approach to the management of biological waste of patient in nuclear medicine departments, which ensure environment protection and radiation safety of people, it is necessary to continue the research including development and modeling of realistic scenario of staff and patient radiation exposure confirmed experimental results.
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KINOSHITA, Isao. "Biological Corrosion of Concrete in Sanitary Sewerage Systems and Treatment Plants." Journal of the Society of Materials Science, Japan 47, no. 10 (1998): 1031–40. http://dx.doi.org/10.2472/jsms.47.1031.
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Belecciu, Liliana. "The legality of the “share” in the billing of the public water supply and sewage service." Supremacy of Law, no. 1 (September 2021): 129–35. http://dx.doi.org/10.52388/2345-1971.2021.1.12.
Повний текст джерелаАнотація:
The public water supply and sewerage service includes the totality of activities of public utility and general economic and social interest carried out for the purpose of the collection, treatment, transportation, storage and distribution of drinking water on the territory of the administrative-territorial unit, as well as for the purpose of the collection and purification of wastewater. This service is regulated, in particular, by the Law on public water supply and sewerage service No. 303/2013. The object of the law represents the creation of the legal framework for the establishment, organization, operation, regulation and monitoring of the public drinking water supply and sewerage service in the conditions of accessibility, availability, reliability, continuity, competitiveness, transparency, respecting quality, safety and environmental protection. Everything that exceeds these activities is not subject to the regulation of the Law No. 303/2013. And the application of the “share” is an illegal activity that is punishable in accordance with the legislation in force.
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Kaczor, Grzegorz B., Krzysztof Chmielowski, and Piotr Bugajski. "Influence of extraneous waters on the quality and loads of pollutants in wastewater discharged into the treatment plant." Journal of Water and Land Development 33, no. 1 (June 1, 2017): 73–78. http://dx.doi.org/10.1515/jwld-2017-0021.
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Abstract The aim of the study was to analyze an influence of an inflow penetrating into two selected small sewerage systems during a rainy weather on pollutant concentration and load in raw sewage. Studies were conducted in 2010–2015 on two small sewerage systems in Małopolska province. The studies confirmed that the inflow penetrating into the sewerage systems resulted in a decrease of pollutant concentrations in sewage. However, they also showed that this dilution was not constant for all types of pollutants. The most important outcome of the study was demonstrating that despite its diluting effect on pollutants, the intense inflow into a sewerage system resulted in an increase of a sewage pollutant load. This increase was not regular, but it was rising dramatically when the inflow share in sewage exceeded 50%. The study indicated that the inflow penetrating into the sewerage system should not be disregarded, as it actually presented a significant threat to the wastewater treatment process and in consequence to the quality of recipient waters.
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ISHIKAWA, SUSUMU. "Purification of municipal sewerage water by high-functional pre-treatment equipment and aerobic filter bed." Journal of Environmental Conservation Engineering 25, no. 3 (1996): 140–44. http://dx.doi.org/10.5956/jriet.25.140.
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Tebai, Larbi, and Ioannis Hadjivassilis. "Soft Drinks Industry Wastewater Treatment." Water Science and Technology 25, no. 1 (January 1, 1992): 45–51. http://dx.doi.org/10.2166/wst.1992.0008.
Повний текст джерелаАнотація:
Soft drinks industry wastewater from various production lines is discharged into the Industrial Effluent Treatment Plant. The traditional coagulation/flocculation method as first step, followed by biological treatment as second step, has been adopted for treating the soft drinks industry wastewaters. The performance of the plant has been evaluated. It has been found that the effluent characteristics are in most cases in correspondence with the requested standards for discharging the effluent into the Nicosia central sewerage system.
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Prăjanu, Costel-Cătălin, Daniel Toma, Cristina-Mihaela Vîrlan, and Nicolae Marcoie. "Studies Related to the Biological Treatment of Wastewater within the Wastewater Treatment Plant of Iași City." Ovidius University Annals of Constanta - Series Civil Engineering 20, no. 1 (December 1, 2018): 57–64. http://dx.doi.org/10.2478/ouacsce-2018-0006.
Повний текст джерелаАнотація:
Abstract This paper includes an analysis of the biological treatment process existing within the water supply and sewerage of Iași City. The main objective of biological treatment is the removal of solid organic substances from wastewater, the stabilization of sludge, the reduction of nutrients loads etc. The Iași City Wastewater Treatment Plant was developed in several stages since year 1968. Nowadays, the facility operates at a design flow rate of 4 m3/s during dry weather and 8 m3/s during heavy rainfalls. This study is focused on the following aspects: wastewater treatment plant’s diagram, the wastewater parameters inside the treatment plant, the biological treatment process analysis and a few conclusions.
Дисертації з теми "Sewerage Purification Biological treatment"
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Silva, Gustavo Henrique Ribeiro da. "Reator compartimentado anaerobio/aerobio, tratando esgoto sanitario : desempenho e operação." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258316.
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Orientador: Edson Aparecido Abdul NourDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil
Made available in DSpace on 2018-08-03T00:31:08Z (GMT). No. of bitstreams: 1 Silva_GustavoHenriqueRibeiroda_M.pdf: 10901410 bytes, checksum: 214e9f14f9626400264bad3cf93fade5 (MD5) Previous issue date: 2001
Resumo: No presente trabalho de pesquisa foi estudada uma alternativa de união de processos anaeróbios e aeróbios sob a forma de um reator compartimentado anaeróbio/aeróbio, no tratamento de esgoto sanitário. O reator era composto por quatro câmaras seqüenciais, sendo as três primeiras anaeróbias e a última aeróbia, totalizando um volume aproximado de 2,5 m3. O Iodo gerado pelo reator foi separado em um decantador laminar e recirculado à quarta câmara. O reator, localizado em uma E.T.E. da cidade de Limeira, SP, foi operado durante um período de 444 dias, divido em cinco fases, com tempo de detenção hidráulica (TDH) total variando de 7 a 16 horas, alimentado com esgoto sanitário que havia recebido tratamento preliminar. As cinco fases de operação corresponderam a 10, 16, 12, 8 e 7 horas de TDH. Os valores de pH ao longo de todas as câmaras e decantador, variaram entre 5,7 e 8,3 e o valor médio foi de 6,8, não sendo necessário correção e pH durante o período de estudo. Os melhores valores de remoção de 0805 foram obtidos na Fase 4 (TDH=8 horas), 56,9 a 95,7%. Contudo o teste estatístico de comparação de médias de duas amostras, verificou não. haver diferença significativa entre as fases, exceto Fase 2, ao nível de P=O,05. O desempenho do reator quanto a remoção de DQOtotal e SST foi semelhante ao obtido para 0805, com valores de 31,4 a 95,6 e 21,0 a 97,3%, respectivamente, o mesmo ocorrendo para o teste estatístico realizado. Os valores encontrados para oxigênio dissolvido no interior da câmara 4 (aeróbia) foram satisfatórios na maior parte do tempo, de acordo com os valores citados na literatura, alcançando valor máximo de 4,70 e mínimo de O mg 02.L-1. A presença do decantador laminar foi importante na remoção de sólidos provenientes do reator. Após o 1070 dia de operação, o Iodo de recirculação apresentou uma sedimentabilidade de boa a ótima. A configuração do sistema em estudo, promove adequado tratamento do efluente aplicado aliado a uma produção de Iodo aeróbio de fácil gerenciamento
Abstract: The present research aimed to study an alternative route for union of aerobic and anaerobic processes, through the use of a baffled reactor, treating sanitary wastewater. The reactor is composed of four sequential chambers, being the first tree anaerobic chambers and the last one aerobic, composing a total volume of approximately 2.5 m3. The sludge generated in the reactor is separated in a laminar sedimentation tank and recycled into the forth chamber. The reactor - placed in a wastewater treating plan of Limeira city, S. P., 8razil -operated in a period of 444 days. This period was divided in five phases, with hydraulic detention times (HOT) varying from 7 to 16 hours. The reactor was fed with sanitary wastewater which had already suffered a preliminary treatment. The five phases of operation corresponded to 10, 16, 12,8 e 7 hours of HOT, respectively. The pH values in all chambers and in the sedimentation tank, varied between 5,7 e 8,3, with a mean value of 6,8; the correction of pH values was not necessary during all periods. The best value of 8005 removal was attained in the Phase 4 (HOT=8 hours), 56,9 to 95,7%. However, the statistic comparison of the means .of two samples showed that there was no significant difference between the phases, except in Phase 2, with P=0,05. The reactor performance, in relation to COOtotal removal and TSS, was similar to that obtained for the 8005, with values of 31,4 to 95,6 and 21,0 to 97,3%, respectively. The same occurred in the statistic test. In chamber 4, the oxygen dissolved values were satisfactory in most of the periods, reaching the maximum of 4,7 and of 0,0 mg 02.L-1. The laminar sedimentation tank was important for removal of solids produced in the sedimentation tank. After the 10ih operation day, the recycled sludge presented a sedimentation capability classified between good and very good. Thus, It is possible to affirm that the baffled reactor configuration of the present work promotes an useful effluent treatment, employed to the production of an aerobic sludge with easy management
Mestrado
Saneamento e Ambiente
Mestre em Engenharia Civil
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Godinho, Jayson Pereira. "Comportamento dinâmico e hidrodinâmico de um reator anaeróbico híbrido (UAHB) submetido à variação de carga hidráulica horária no tratamento de esgoto sanitário." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2548.
Повний текст джерелаАнотація:
CAPESO processo de digestão anaeróbia é muito importante no tratamento dos esgotos sanitários, por ser eficiente, simples e de baixo custo de implantação, operação e manutenção. Embora o Brasil tenha à disposição processos anaeróbios consolidados, o saneamento básico ainda é deficiente no país, e a otimização de reatores anaeróbios tem o intuito de melhorar a viabilidade, efetividade e ampliação dos sistemas de tratamento dos esgotos sanitários. O objetivo deste projeto foi avaliar o desempenho através do comportamento dinâmico e hidrodinâmico de reator anaeróbio híbrido (UAHB), com variação do tempo de detenção hidráulica (TDH) de 4 a 12 h e da DQO (amostras brutas) de 250 a 1250 mgO2L-1. O reator, com volume útil de 22,1 L, foi operado com meio suporte de anéis corrugados de Policloreto de Polivinila (PVC) e mantido a temperatura ambiente, sendo o afluente de alimentação, sintético simulando o esgoto sanitário. Foram analisados os parâmetros físico-químicos: temperatura do líquido e do ar, pH, alcalinidade total (AT), alcalinidade a bicarbonato (AB), ácidos voláteis (AV), demanda química de oxigênio (DQO), demanda bioquímica de oxigênio (DBO520), Turbidez, Sólidos Totais (ST), Sólidos Suspensos Totais (SST), nitrogênio total kjeldahl (N-NTK), nitrogênio amoniacal (Namon), nitrito(N-NO2-), nitrato (N-NO3-) e fósforo total (P). Foi avaliado o comportamento hidrodinâmico e verificada a existência de anomalias hidráulicas, pela técnica de estímulo-resposta tipo pulso com injeção do traçador eosina Y. Ao final dos experimentos, foi realizada a análise estatística para encontrar a condição operacional ótima, bem como os modelos estatísticos para validação dos experimentos. Em todas as condições operacionais foi possível observar que o reator UAHB entrou em equilíbrio dinâmico aparente (EEDA) com produção de alcalinidade para neutralizar os ácidos voláteis produzidos no processo de acidogênese e acetogênese da digestão anaeróbia. O aumento da carga orgânica volumétrica acarretou no aumento das eficiências de remoção em DQO (amostras brutas e filtradas), DBO520 e Turbidez, mas reduziu as remoções de Sólidos Totais e Sólidos Suspensos Totais. A diminuição do TDH reduziu as eficiências de remoção dos parâmetros DQO (amostras brutas e filtradas), DBO520, Sólidos Totais, Sólidos Suspensos Totais e Turbidez. Em relação à hidrodinâmica, em todas as condições operacionais foi observado o efeito de cauda longa, o regime de escoamento no interior do reator UAHB foi classificado como de tanques de mistura completa em série (NCSTR). Foi verificada a presença de zonas mortas no reator, a eficiência hidráulica foi em média 65% para as três condições e não foi possível observar a presença de curtos-circuitos para os três TDH testados. Pela análise estatística do delineamento composto central rotativo (DCCR), a condição ótima de operação para o reator foi para o TDH 12 h e DQO (amostras brutas) 553 mgO2.L-1.
The anaerobic digestion process is very important in the treatment of sewage, as it is an efficient, simple process and low cost of implementation, operation and maintenance. Although Brazil has provided consolidated anaerobic processes, sanitation is still poor in the country, and the optimization of anaerobic reactors aims to improve the viability, effectiveness and expansion of treatment systems for sewage. The aim of this research project is to evaluate the reactor's performance through dynamic and hydrodynamic behavior of hybrid anaerobic reactor (UAHB) with a range of hydraulic retention time (HRT) of 4 to 12 hours and COD (gross samples) 250 - 1250 mgO2L -1. The reactor, with a volume of 22.1 L was operated with support means corrugated rings of Polyvinyl chloride (PVC) and kept at room temperature, the influent feed, simulating the synthetic wastewater. the physicochemical parameters were analyzed: temperature of the liquid and air, pH, total alkalinity (TA), bicarbonate alkalinity (BA), volatile acids (VA), chemical oxygen demand (COD), biochemical oxygen demand (BOD ), Turbidity, Total Solids (TS), total suspended solids (TSS), nitrogen Total Kjeldahl (NTK-N), ammonia nitrogen (amon-N), nitrite (NO2-N), nitrate (NO3-N) and Total phosphorus (P). It evaluated the hydrodynamic behavior and the determination of hydraulic anomalies, the stimulus-response pulse technique with injection of the tracer eosin Y. At the end of the experiments, statistical analysis was performed to find the optimal operating condition as well as the statistical models for validation experiments. In all operating conditions it was observed that the UAHB Reactor became apparent dynamic equilibrium (ADE) with alkalinity production to neutralize the volatile acids produced in acetogenesis process of anaerobic digestion. The increased of organic loading rate resulted in increased efficiencies in the removal of COD (gross and filtered samples), BOD and Turbidity, but reduced removals of Total Solids and Total Suspended Solids. The decrease in HRT reduced the removal efficiencies of COD parameters (grosss and filtered samples), BOD, Total Solids, Total Suspended Solids and Turbidity. Regarding the hydrodynamic in all operating conditions was observed long tail effect, the flow regime inside the reactor UAHB was rated as complete mixing tanks in series (N-CSTR). The presence of dead zones in the reactor was checked, the hydraulic efficiency was averaged 65% for the three conditions and it was not possible to observe the presence of short circuits for the three HRT tested. For the statistical analysis of the central rotary compound design (CRCD), the optimum operating condition for the reactor was to HRT 12 h and COD (gross samples) 553 mgCOD.L-1.
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Hung, Chien-ho. "Fate of thiocyanate in biological treatment processes." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/20864.
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Wells, Charles Digby. "Tertiary treatment in integrated algal ponding systems." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1006162.
Повний текст джерелаАнотація:
Inadequate sanitation is one of the leading causes of water pollution and consequently illness in many underdeveloped countries, including South Africa and, specifically, the Eastern Cape Province, where cholera has become endemic. As modern wastewater treatment processes are often energy intensive and expensive, they are not suitable for use in these areas. There is thus a need to develop more sustainable wastewater treatment technologies for application in smaller communities. The integrated algal ponding system (IAPS) was identified as a possible solution to this wastewater management problem and was investigated for adaptation to local conditions, at the Rhodes University Environmental Experimental Field Station in Grahamstown, South Africa. The system was monitored over a period of nine years, with various configuration adjustments of the high rate algal pond (HRAP) unit operation investigated. Under standard operating conditions, the system was able to achieve levels of nutrient and organic removal comparable with conventional wastewater treatment works. The mean nitrate level achieved in the effluent was below the 15mg.l-1 South African discharge standard, however, nitrate removal in the IAPS was found to be inconsistent. Although the system was unable to sustain chemical oxygen demand (COD) removal to below the 75mg.l-1 South African discharge standard, a removal rate of 87% was recorded, with the residual COD remaining in the form of algal biomass. Previous studies in the Eastern Cape Province have shown that few small wastewater treatment works produce effluent that meets the microbial count specification. Therefore, in addition to the collation of IAPS data from the entire nine year monitoring period, this study also investigated the use of the HRAP as an independent unit operation for disinfection of effluent from small sewage plants. It was demonstrated that the independent high rate algal pond (IHRAP) as a free standing unit operation could consistently produce water with Escherichia coli counts of 0cfu.100ml-1. The observed effect was related to a number of possible conditions prevailing in the system, including elevated pH, sunlight and dissolved oxygen. It was also found that the IHRAP greatly enhanced the nutrient removal capabilities of the conventional IAPS, making it possible to reliably and consistently maintain phosphate and ammonium levels in the final effluent to below 5mg.l-1 and 2mg.l-1 respectively (South African discharge standards are 10mg.l-1 and 3mg.l-1 in each case). The quality of the final effluent produced by the optimisation of the IAPS would allow it to be used for irrigation, thereby providing an alternative water source in water stressed areas. The system also proved to be exceptionally robust and data collected during periods of intensive and low management regimes were broadly comparable. Results of the 9 year study have demonstrated reliable performance of the IAPS and its use an appropriate, sustainable wastewater treatment option for small communities.
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Whitehead, Alan Joseph. "Experimental culture of duckweed (Lemnaceae) for treatment of domestic sewage." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26665.
Повний текст джерелаАнотація:
The culture of the floating aquatic plant, duckweed (Lemna minor), as an agent of domestic sewage treatment was studied in a clarification lagoon at Duncan, British Columbia, during the summer of 1986. Duckweed was grown in plastic fabric tanks (3700 L volume, 1.85 m deep, 2.25 m² water surface area) receiving 290 L of sewage per day or 12.8 d hydraulic retention time. Three treatments were tested: cropped duckweed, uncropped duckweed, and no duckweed. Water quality, plant growth and tissue composition were monitored on the basis of weekly sampling.
Removals of VSS, COD, total-N and total-P were greater in the presence than in the absence of duckweed. Unmeasured imports of N and P masked the effect of plant uptake on reducing nutrient concentrations in the tank effluents. Sustainable duckweed yields were possible at both cropping rates, despite a severe infestation of aphids. Dry matter yields of 2.0 g/m².d and 6.4 g/m².d were obtained at the 15%/week and 50%/week cropping rates, respectively. Duckweed contained 6.1 - 6.4% N and 1.1 - 1.4% P (dry wt.). Plant harvest removed 0.14 g N/m².d and 0.03 g P/m².d at the 15%./week and 0.31 g N/m².d and 0.07 g P/m².d at the 50%/week cropping rates. Cropping increased the fraction of total-N and total-P loading that could be removed via plant uptake.
Performance of the experimental treatments is analyzed in the light of concentration data, mass balances, and mass flux estimations. Possible sources of unmeasured N and P imports are discussed, and recommendations for future research are provided. The results suggest that duckweed may hold promise under certain conditions as a means of polishing sewage lagoon effluent.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Liu, Hong, and 劉紅. "Bio-hydrogen production from carbohydrate-containing wastewater." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31244518.
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Li, Yun, and 李贇. "Formation and stability of aerobic granular sludge in biological wastewater treatment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/197519.
Повний текст джерелаАнотація:
Aerobic sludge granulation is a new technology that has been developed for biological wastewater treatment. Compared with conventional activated sludge, aerobic granules allow better sludge-water separation and a higher biomass concentration. However, the mechanism of the transformation from sludge flocs to granular sludge under the aerobic condition is still unclear. Deterioration of aerobic granules in long-term operation is also a concern for its scale-up application. The present study was conducted to investigate the crucial factors for aerobic granulation and its underlying mechanism. In addition, the stability of aerobic granules under unfavorable conditions and the recovery of deteriorated granules in bioreactors were also studied.
For formation of aerobic granules, gelation-facilitated biofilm growth was proposed as a new mechanism for the granulation process. Simulation of granule formation was performed in a well-controlled chemical system to provide an experimental proof for the proposed aerobic granulation theory. Granule formation was achieved in a particle suspension with latex microspheres for bacterial cells and alginate and peptone for extracellular polymeric substances (EPS), together with the cation addition and floc discharge. In the mixture with the dosing of alginate and a small amount of peptone, artificial gels and granules could be well formed, and the artificial granules share the similar micro-structure as the aerobic bacterial granules. However, as the dose of peptone increased, gels were not formed and only large particle flocs were produced. The formation of artificial granules proves that effective EPS interactions with cations and the subsequent gelation are crucial to aerobic granulation in bioreactors. In relation to granulation, the effect of the substrate feeding pattern on the microbial yield was tested. The results show that the bioreactor with a more frequent substrate feeding interval had a lower sludge yield than the reactor (0.45 vs. 0.55) with a less frequent feeding. The sludge fed less frequently was able to store more substrates as intracellular substances, resulting in more biomass growth. Moreover, a long feeding interval would force the biomass into the feast-famine regime, which was found to enhance microbial growth and granulation, producing granules with a compact and stable structure.
For the stability of aerobic granules, various factors that would been countered in biological wastewater treatment were experimented. The results show that granules deteriorated in structure under unfavorable conditions, such as a low solution pH (pH~6.0), a high loading rate, and feed of starch instead of glucose into the bioreactors. In some deterioration cases, filamentous bacterial growth became more dominant and the granules became loose and fluffy flocs. Compared to mature granules, fresh granules were less stable and more vulnerable to the unfavorable conditions. As the granules deteriorated in structure, their surface roughness values increased considerably from 35 or less to more than 230. Under a favorable condition with a feed of sodium acetate, the deteriorated granules could be recovered in some reactors. However, deterioration of the granules caused by filamentous growth at a low pH or high loading rate could hardly be recovered.published_or_final_version
Civil Engineering
Master
Master of Philosophy
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Palazolo, Paul Joseph. "Use of genetic algorithms in bounded search for design of biological nitrification/denitrification waste treatment systems." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/32777.
Повний текст джерела
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Morrison, Kirk Murray. "An assessment of the potential for biological phosphorus removal in Canadian wastewater treatment plants." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28507.
Повний текст джерелаАнотація:
This thesis assesses the potential for enhanced biological phosphorus (Bio-P) removal in Canadian wastewater treatment plants. Retrofit designs incorporating Bio-P removal were prepared for nine wastewater treatment plants across Canada, and were compared against chemical phosphorus removal technologies. Incremental capital and operating costs were calculated and internal rates of return (IRR's) for the capital investment required to install the Bio-P removal facilities were calculated. Based on these results, an assessment of the potential use for the technology in Canada is made.
Of the nine plants studied, results indicate that Bio-P removal is economically superior to chemical phosphorus removal for the Calgary Bonnybrook, Edmonton Gold Bar, Saskatoon Mclvor Weir and Regina wastewater treatment plants. In general, Bio-P removal appears to offer significant economic advantages to
plants located in Alberta and Saskatchewan because of the high
cost of phosphorus removal chemicals in these provinces. The
present low cost of phosphorus removal chemicals in Ontario and
Quebec likely limits the viability of Bio-P removal to large (greater than 300,000 m³/d), suitably configured plants. In British Columbia, where Bio-P removal is presently used in the Okanagan Valley, the absence of widespread provincial phosphorus removal standards makes future Bio-P installations unlikely. The potential for Bio-P removal in Manitoba, the Maritimes and the Yukon and Northwest Territories is again limited by the absence of phosphorus removal standards in these parts of Canada.
Results also indicate that the use of an anoxic/anaerobic/ aerobic process in the bioreactor, in conjunction with primary sludge fermentation through gravity thickening, is very applicable to Canadian plants and offers potential capital and operating cost savings relative to other Bio-P processes. The common practice of anaerobic sludge digestion, combined with sludge dewatering and land application, was found to be unfavourable from a Bio-P perspective unless the resulting supernatant/filtrate streams can be re-used or disposed of outside of the mainstream treatment process.
Through the preparation of the retrofit designs, it was
determined that certain aspects of Bio-P technology require additional research in order to optimize treatment plant design.
These include kinetic modelling; short SRT Bio-P removal; the
anorexic/anaerobic/aerobic process; the use of gravity thickening
for primary sludge fermentation; and phosphorus release during anaerobic digestion.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Stephenson, Robert John. "A comparison of retained biomass anaerobic digester designs." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26740.
Повний текст джерелаАнотація:
The principles behind anaerobic digestion are fairly well understood, but the limits of application of each digester design are not known. Because there are significant differences in the properties of the many wastewaters requiring treatment optimal anaerobic digester performance requires the matching of feed characteristics to a digester design and mode of operation. No consensus has yet emerged on digester design, operating conditions or feed/digester match-ups.
In this study, three bench scale retained biomass anaerobic digester designs were examined for their response to a sequence of varied hydraulic retention times (HRTs) and influent wastewater concentrations. The digester designs studied were the upflow anaerobic filter, the upflow anaerobic expanded bed and the upflow anaerobic sludge bed. The wastewater was screened and diluted dairy cow manure obtained from the UBC dairy barn. The parameters monitored included the total and soluble chemical oxygen demand (TCOD and SCOD), volatile and suspended solids (VS and SS), total volatile fatty acids (VFAs), total Kjeldahl and ammonia nitrogen (TKN and NH₃-N), pH, biogas production, and the methane (CH₄) and carbon dioxide (C0₂) content of the biogas.
Wastewater treatment efficiencies, measured in terms of TCOD, SCOD, VS, and TVFA removals, and methane productivity and methane yield for each of the digester designs were examined for the range of the operating conditions.
The anaerobic filter digester effected a mean TCOD removal efficiency of 47% ± 14% at a mean 4.0 day HRT, 51% ± 9% at a mean 2.3 day HRT and 35% ± 11% at a mean 1.3 day HRT. The expanded bed digester effected a mean TCOD removal of 45% ± 15% at a mean 4.3 day HRT, 38% ± 12% at a mean 2.5 day HRT and 28% ± 9% at a mean 1.3 day HRT. The sludge bed digester effected a mean TCOD removal of 53% ± 9% at a mean 3.8 day HRT, 45% ± 12% at a mean 2.2 day HRT and 32% ± 10% at a mean 1.2 day HRT. For all three digesters, the difference in the treatment efficiency over the range of HRTs tested, from 5 to 1.25 days was not in proportion to the change in HRT. Methane productivity, measured against either the removal or addition of substrate in terms of TCOD, SCOD, VS and TVFA, demonstrated considerable variability. Methane production increased with both substrate addition and substrate removal. Methane yield increased with increasing HRT. The sludge bed digester generally exhibited the greatest but most variable methane yields. It produced 0.095 L CH₄/g VS added at a mean 3.8 day HRT and 0.037 L CH₄/g VS added at a mean 1.2 day HRT. The anaerobic filter delivered the greatest methane yield at the intermediate HRT, 0.044 L CH₄/g VS added at a mean 2.3 day HRT. The expanded bed demonstrated low methane yields over the range of feed strengths and HRTs tested.
Biogas composition averaged 62.1% methane and 17.1% carbon dioxide for the anaerobic filter, 43.6% methane and 5.3% carbon dioxide for the expanded bed. and 61.1% methane and 18.9% carbon dioxide for the sludge bed.Applied Science, Faculty of
Graduate
Книги з теми "Sewerage Purification Biological treatment"
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T, Daigger Glen, and Lim Henry C. 1935-, eds. Biological wastewater treatment. 2nd ed. New York: Marcel Dekker, 1999.
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Biotechnology and wastewater treatment. Cambridge [Cambridgeshire]: Cambridge University Press, 1985.
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Biological wastewater treatment systems: Theory and operation. Chichester: Wiley, 1990.
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Winkler, Eric S. Design guidance for shallow trench low pressure pipe systems. Amherst, Mass: Center for Energy Efficiency and Renewable Energy, University of Massachusetts at Amherst, 2001.
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5
K, Wang Lawrence, Hung Yung-Tse, and Shammas Nazih K, eds. Physicochemical treatment processes. Totowa, N.J: Humana Press, 2005.
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K, Wang Lawrence, Hung Yung-Tse, and Shammas Nazih K, eds. Advanced physicochemical treatment processes. Totowa, N.J: Humana Press, 2006.
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Biowaste and biological waste treatment. London: James & James, 2001.
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Handbook of water and wastewater treatment technology. New York: M. Dekker, 1995.
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Winkler, M. A. Biological treatment of waste-water. Chichester: Horwood, 1997.
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Winkler, M. A. Biological treatment of waste-water. Chichester: Ellis Horwood, 1998.
Знайти повний текст джерелаЧастини книг з теми "Sewerage Purification Biological treatment"
1
Bhunia, P. "Fundamentals of Biological Treatment." In Comprehensive Water Quality and Purification, 47–73. Elsevier, 2014. http://dx.doi.org/10.1016/b978-0-12-382182-9.00048-7.
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Rastogi, Rupali. "Water Purification Using Different Chemical Treatment." In Advances in Environmental Engineering and Green Technologies, 338–67. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-6111-8.ch019.
Повний текст джерелаАнотація:
Water from surface sources is often contaminated by microbes, whereas groundwater is normally safer, but even groundwater can be contaminated by harmful chemicals from human activities or from the natural environment. The purification process of water may reduce the concentration of particulate matter including suspended particles, parasites, bacteria, algae, viruses, fungi, and a range of dissolved and particulate material derived from the surfaces. Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. Most water is purified for human consumption (drinking water), but water purification may also be designed for a variety of other purposes, such as medical, pharmacology, chemical, and industrial applications. In general, the methods used include physical processes such as filtration and sedimentation, biological processes such as slow sand filters or activated sludge, chemical processes such as flocculation and chlorination, and the use of electromagnetic radiation such as ultraviolet light.
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"Palm Oil Mill Wastewater and Treatment." In Membrane Technology for Water and Wastewater Treatment in Rural Regions, 283–305. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2645-3.ch011.
Повний текст джерелаАнотація:
Palm oil is an essential agricultural commodity in Malaysia, as Malaysia is one of the largest producers and exporters globally. The processes of palm oil extraction and purification generate a large amount of wastewater known as palm oil mill effluent (POME). Currently, most treatment processes are carried out using a conventional ponding system which is outdated as it requires large land areas and long retention time. Discharge of poorly treated POME directly to the surroundings leads harms the environment, as it contains high contents of oil and BOD. Therefore, this chapter discusses the treatment method of POME from a newer perspective of membrane technology integrated with biological treatment. Various methods such as clarification system with nanofibre unit, cooling system, activated sludge system, and anaerobic membrane bioreactor, are reviewed on their principles of operation.
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Belekar, R. M., and d. S. J. Dhoble. "Review on Water Purifications Techniques and Challenges." In Water Pollution Sources and Purification: Challenges and Scope, 1–27. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/9789815050684122010004.
Повний текст джерелаАнотація:
Nowadays, the whole world is facing water containment issues caused by anthropogenic sources, including household waste, agricultural waste, and industrial waste. There is a huge impact of wastewater on the environment; hence, the public concern over it has been increased. This led researchers to be motivated and find radical and cheap solutions to overcome this problem. Several conventional techniques, including boiling, filtration, sedimentation, and chlorination, are used for wastewater treatment; however, they have limited scope. Some other methods like coagulation, flocculation, biological treatment, Fenton processes, advanced oxidation, membrane.based processes, ion exchange, electrochemical, adsorption, and UV-based processes have been applied to remove pollutants, but there are still some limitations. This review chapter sheds some light on these traditional and modern methods applied for water treatment, along with their advantages and disadvantages. These methods have the potential to remove pollutants from wastewater, such as natural organic matter, heavy metals, inorganic metallic matter, disinfection byproducts, and microbial chemicals. The potential threats and challenges of using water treatment methods for safe water production have also been discussed in this chapter. Nowadays, the whole world is facing water containment issues caused by anthropogenic sources, including household waste, agricultural waste, and industrial waste. There is a huge impact of wastewater on the environment; hence, the public concern over it has been increased. This led researchers to be motivated and find radical and cheap solutions to overcome this problem. Several conventional techniques, including boiling, filtration, sedimentation, and chlorination, are used for wastewater treatment; however, they have limited scope. Some other methods like coagulation, flocculation, biological treatment, Fenton processes, advanced oxidation, membrane.based processes, ion exchange, electrochemical, adsorption, and UV-based processes have been applied to remove pollutants, but there are still some limitations. This review chapter sheds some light on these traditional and modern methods applied for water treatment, along with their advantages and disadvantages. These methods have the potential to remove pollutants from wastewater, such as natural organic matter, heavy metals, inorganic metallic matter, disinfection byproducts, and microbial chemicals. The potential threats and challenges of using water treatment methods for safe water production have also been discussed in this chapter.
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Yareni Andrade Avila, Yasvet, Julián Cruz-Olivares, and César Pérez-Alonso. "Antioxidant Effect and Medicinal Properties of Allspice Essential Oil." In Essential Oils - Advances in Extractions and Biological Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103001.
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Pimenta dioica L. Merrill. Myrtaceae family, known for its berries called pimenta or allspice, is one of the oldest spices in the world, widely used for its culinary and medicinal qualities. The main commercial product obtained from this spice is its essential oil, the reason for the interest in essential oil is based on the versatility of its use in different industrial areas (food, cosmetics, perfumery, and pharmaceuticals) due to its harmless and beneficial effects for health. In addition, it contains compounds that have shown broad biological activity, which turns out to be useful in the treatment of diseases related to the excessive formation of oxygen radicals. As a result, the extraction process and operating conditions have a significant impact on the bioactivity of these molecules. As a consequence, selecting the correct mix of variables to improve oil extraction and functionality is essential. The most of study on this essential oil is being focused on resolving these issues, as well as purification and identification. This chapter will cover the methods for obtaining P. dioica essential oil, as well as the chemical profile of the oil and its biological properties, which include its effects on humans, plants, animals, insects, and microorganisms.
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Dutta, Mintu Maan, and Anushmita Charingia. "Nanotechnology-Based Nano-Biosorbents." In Handbook of Research on Emerging Developments and Environmental Impacts of Ecological Chemistry, 386–408. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1241-8.ch018.
Повний текст джерелаАнотація:
Most countries worldwide face the problem related to clean and safe water. The major source of contamination of water bodies includes the discharges of wastes from various domestic and industrial sources (heavy metal ions, dyes, and pharmaceuticals). To overcome those problems, various water purification methods such as coagulation, flocculation, adsorption, membrane separation, biological, and electrochemical methods have been engaged. Adsorption using nano-biosorbents based on chitin, chitosan and modified chitosan, cellulose, alginate, micro algal has emerged as a better alternative for the removal of contaminants from drinking and wastewater treatment. The main advantages of these nano-biosorbents include its biodegradability and eco-friendliness, which have attracted researchers to this field.
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Lindgren, Elisabet, My S. Almqvist, and Thomas Elmqvist. "Ecosystem services and health benefits—an urban perspective." In Oxford Textbook of Nature and Public Health, edited by Matilda van den Bosch and William Bird, 257–63. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780198725916.003.0017.
Повний текст джерелаАнотація:
Ecosystem services provide water, food, shelter, fuelwood, fibres, and medicinal plants, and contribute to local and global climate regulation, moderation of extreme events, run-off mitigation, erosion prevention, waste treatment, air purification, noise reduction, pollination, biological control, and biodiversity—conditions that all directly and indirectly influence human health. In addition, ecosystem services provide recreation, mental and physical health, and aesthetic and spiritual considerations. A rapidly urbanizing world in combination with global changes are creating new health risks or enhancing existing health concerns. Possible impacts on human health of ecosystem services were evaluated in three different urban environments (i.e. affluent mature, affluent growing, and low-income growing). The outcomes suggest that several health concerns in cities worldwide can be reduced or avoided by acknowledging and integrating beneficial impacts on health from ecosystem services in urban planning.
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Alma, M. Hakkı, and Tufan Salan. "Alternative Fuels." In Energy: Concepts and Applications, 327–446. Turkish Academy of Sciences, 2022. http://dx.doi.org/10.53478/tuba.978-625-8352-00-9.ch06.
Повний текст джерелаАнотація:
Nowadays, a wide range of value-added fine chemicals, alternative biofuels and eco-friendly polymeric materials can be produced from lignocellulosic biomass sources via thermochemical, biological or catalytic routes in the biorefinery. For the sustainable production of biofuels, abundant, easy accessible and renewable biomass-based feedstock has an important key role to replace petroleum oil in the production of liquid hydrocarbon fuels for the transportation sector with a zero carbon footprint. The biofuel can be defined as the solid, liquid, or gaseous fuels which are predominantly obtained from these biomass based raw materials. However, thepre-treatment, production and purification processes differ greatly based on the feedstock type, used technology and desired fuel type. Thus, to eliminate the contradiction in terms, biofuels are classified from first to fourth generation at the present time. This chapter review the several liquid biofuel type along with production methods, technologies and feedstock types based on that generation classification.
Тези доповідей конференцій з теми "Sewerage Purification Biological treatment"
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Yu, Feng, Hongqi Zhu, and Yanjun Yin. "The Biological Purification Project Practice of the Sewage Treatment Station’s Odor." In 2015 Asia-Pacific Energy Equipment Engineering Research Conference. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/ap3er-15.2015.87.
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Chirikanova, Yu S. "MODELING OF WASTEWATER TREATMENT." In Всероссийская научная конференция, посвященная памяти доктора технических наук, профессора Александра Дмитриевича Потапова. Федеральное государственное бюджетное образовательное учреждение высшего образования "Национальный исследовательский Московский государственный строительный университет" (НИУ МГСУ), 2021. http://dx.doi.org/10.22227/978-5-7264-2875-8.2021.159-162.
Повний текст джерелаАнотація:
The paper deals with the problem of mathematical modeling of biological wastewater treatment. The peculiarity of the biological treatment system is that a block with activated sludge, called an aeration tank, is used for water purification. To describe the process of biological wastewater treatment in aeration tanksa mathematical model developed in the GPS-X software package is proposed.
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Juškaitė, Loreta, and Alvydas Zagorskis. "Microalgae Strains Monoraphidium Griffithi and Chlorella sp. for the Carbon Dioxide Capture from Biogas." In 11th International Conference “Environmental Engineering”. VGTU Technika, 2020. http://dx.doi.org/10.3846/enviro.2020.720.
Повний текст джерелаАнотація:
One of the most important tools for mitigating climate change is biogas production. Increasing their use requires improving the energy value of biogas by reducing its carbon dioxide content while increasing the methane concentration in biogas. Biological purification of biogas using microalgae strains − merging biogas upgrading method where microalgae use carbon dioxide for their growth during the process of photosynthesis. A four-column photobioreactor was constructed with Monoraphidium Griffithi, Chlorella sp. microalgae strains, distilled water and MWH medium for purification of biogas. Experimental studies determined sizes, shapes and of microalgae cells, the pH changes of mediums used after biogas treatment and the composition of biogas before and after upgrading using photobioabsorber. Microalgae Monoraphidium Griffithi was estimated to have the greatest contribution to CO2 reduction by decreasing from 31.0% to 10.0%. The smallest reduction in CO2 was recorded when biogas was flowing through MWH medium. Experiments have shown that the absorption of biogas components results in the release of oxygen. As the biogas was flowing through all suspensions, the oxygen concentration increased from 3.6 to 5.2%.
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Philips, M., A. G. Juul, S. Thorsen, J. Selmer, and L. Thim. "PURIFICATION AND CHARACTERIZATION OF REACTIVE AND NON-REACTIVE PLASMINOGEN ACTIVATOR INHIBITOR-1 (PAI-1) FROM HUMAN PLACENTA." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642806.
Повний текст джерелаАнотація:
Reactive and non-reactive forms of PAI-1 have been identified in various biological materials. The structural differences between these forms remain to be determined.A monoclonal antibody specific for a non-reactive PAI-1 and a monoclonal antibody reacting with both the reactive and nonreactive form of the inhibitor were obtained by immunization with a tissue-type plasminogen activator (t-PA)-PAI-1 complex (Philips et al., Thromb Haemostas 1986; 55:213-7). These antibodies were used for the isolation of reactive and non-reactive PAI-1 by solid-phase immunoadsorption from extracts of human placenta. The inhibitor preparations were further purified by HPLC. Reactive and non-reactive PAI-1 both migrated with a Mr ∼ 52,000 when analyzed by SDS-PAGE. Furthermore, the two inhibitor forms were indistinguishable by N-terminal sequence analysis. Two N-terminal sequences were found in about equal ammounts for both the reactive and non-reactive PAI-1. They were Ser-Ala-Val-His-His-Pro-Pro- and a two residues shorter sequence (Val-His-His-Pro-Pro-). These sequences are in agreement with the published cDNA sequence of PAI-1 and shows that the inhibitor is N-terminally heterogeneously processed. The second order rate constant (ki) for the reaction between reactive PAI-1 and single-chain t-PA was about 6 106 M-1s-1. Treatment with 4 M guanidinium-HCl partially converted the non-reactive PAI-1 to a reactive form exhibiting a similar k1 for inhibition of single-chain t-PA. SDS-PAGE showed that the t-PA-PAI-1 complex could be dissociated by 1,5 M NH4OH/ 39 mM SDS resulting in the release of a PAI-1 with approximately the same Mr as native PAI-1. This indicates either that t-PA does not cleave the inhibitor or that it cleaves a peptide bond close to the C-terminus.In conclusion a non-reactive and a reactive form of PAI-1 can be purified from placenta. The two forms are distinguishable by monoclonal antibodies but they show similar Mr′ls and the same N-terminal sequences.
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Vermeer, C., BA M. Soute, and MM W. Ulrich. "IN VITRO CARBOXYLATION OF EXOGENOUS PROTEIN SUBSTRATES BY VITAMIN K-DEPENDENT CARBOXYLASE." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643994.
Повний текст джерелаАнотація:
In vivo treatment of experimental animals with vitamin K-antagonists induces the accumulation of non-carboxylated coagulation factor precursors in the liver, where they are tightly bound to vitamin K-dependent carboxylase. If hepatic carboxylase is isolated from warfarin-treated animals, it is obtained therefore almost exclusively in the form of an enzyme/substrate complex. If carboxylase is prepared from non-treated animals, on the other hand, the resulting enzyme is predominantly substrate-free. Small substrates like F L E E L or decarboxylated osteocalcinare carboxylated equally well by both types of carboxylase, but protein substrates(Mr > 30 000) are recognized exclusively by substrate-free carboxylase.Initial attempts to purify carboxylasewere performed with livers from warfarin-treated cows as a starting material. Antibodies against the normal blood coagulation factors crossreact with the hepatic precursor proteins so that the enzyme/substrate complexes could be specifically extracted from detergent-solubilized microsomes by the substrate/antibody interaction. This procedure resulted ina substantial purification of carboxylase, but because its endogenous substrate remained firmly bound, even after it had been carboxylated in vitro, the enzyme system was not suitable for the carboxylation of protein substrates.Therefore a second strategy was developed by which substrate-free carboxylase (from normal livers) was partly purified by sequential extraction of the microsomal membranes with detergents, followed by ammonium sulfate precipitation and size exclusion chromatography.This procedure resulted in a soluble carboxylase complex, still consisting of 7 proteins and phosphatidylcholine. Although further dissociation of the complex resulted in a complete loss of activity, it is not sure if all components play a role in the carboxylation reaction. Exogenous substrates which could be carboxylated by substrate-free carboxylase were: the penta-peptide F L E E L, descarboxyprothrombin from bovine plasma, thermally decarboxylated osteocalcin from bovine bone and non-car-boxy lated coagulaton factor precursors which had been produced by recombinant-DNA techniques in various laboratories. The . efficiency of CO^ incorporation was: 1 mole per 100 moles of F L E E L, 1 mole per 240 moles of descarboxy-prothrombin, 1 mole per mole of decarboxylated osteocalcin and 8 moles per mole of a recombinant factor IX precursor. We assume that the high efficiency with which the recombinant coagulation factor precursors were carboxylated is due to the presence of at least part of their leader sequence. The importance of the aminoacid chain preceding the first carboxylatable Glu residue is demonstrated by the fact that descarboxylated osteocalcin of bovine origin is carboxylated with a relatively high efficiency, whereas descarboxylated osteocalcin from monkey bone is not recognized atal.. Yet the only difference between the two substrates is found in their aminoacids 3 and 4, whereas the first carboxylatable Glu occurs at position 17. It seems, therefore, that the aminoacids 1-16 in bovine osteocalcin mimic to some extent part of the leader sequence in the coagulation factor precursors. Chemical or biochemical modification of decarboxylated osteocalcin might reveal which structural features contribute to its recognition by hepatic carboxylase.The optimal conditions for carboxylation include a high concentration of dithiols (e.g. DTT) and under these conditions disulfide bridges are reduced. Obviously this will lead to a complete destruction of the biological activity of various carboxylated products. Therefore we have searched for a more natural reducing system and it was found that the bacterial thioredoxin/thiore-doxin-reductase system in the presence of 40 uM NADFH was able to replace DTT in the reaction mixtures. Since a comparable system also occurs in calf liver it seems not unlikely that this is the physiological counterpart of the dithiols used in vitro.