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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Evaluation of water treatment efficiency at Cheng-Ching Lake Water Treatment Plant and contaminants transport in distribution systems

Chien, Chuan-Chi 13 February 2007 (has links)
Cheng-Ching Lake water treatment plant (CCLWTP), the largest water treatment plant in southern Taiwan serving the Kaoping region, uses the Kaoping River water as the source water. The plant has encountered both technical and managerial challenges to implement advanced water treatment system since 2004 in order to provide high quality drinking water to the residents living in the Kaoping metropolitan area and to meet future stringent drinking water standards. Granular activated carbon (GAC), derived from wood, bituminous coal, lignite, or other carbon-containing materials, and is the most widely utilized adsorbent for treating water and wastewater. It is usually used after the sand filtration process in water or wastewater treatment plant; the exhausted GAC is re-activated by a combustion process. Moreover, biological activated carbon (BAC) filtration (biofiltration) has become one of the advanced treatment techniques applied in the water treatment plant. In general, BAC offers a large internal surface area for the adsorption of taste, odor, and color compounds, excess chlorine, toxic and mutagenic substances (e.g., bromide, chlorinated organic compounds, including trihalomethanes), trihalomethane precursors, pesticides, phenolic compounds, dyes, toxic metals, and substances that cause biological after growth. After the biofiltration process, a final disinfection is necessary to ensure the microbial quality of the treated water. Because biofiltration is usually not capable of removing biorefractory substances, pre-oxidation with ozone is usually applied for oxidizing the most biorefractory organic matters and also improving their biodegradability before the water is treated in the BAC process. Hence, using ozone pre-oxidation will greatly enhances the effectiveness of the subsequent BAC process. The CCLWTP effluent meets the current drinking water quality established by Taiwan Environmental Protection Administration (TEPA). However, the microbial regrowth due to the residual minute quantity of organic carbons causes pipe corrosion, and the formation of disinfectant by-products (DBPs) in the distribution system leading to potential contaminations of the clean water after it enters into the distribution system. Thus, monitoring the water quality in water distribution systems necessity to develop appropriate strategies for managing both the treatment plant and following distribution systems. Chlorine is often used in municipal water treatment plant for disinfecting drinking water; it can react with naturally occurring organic matter to form trihalomethanes (THMs), e.g. chloroform, bromodichloromethane, chlorodibromomethane and bromoform that causes long-term health hazards to consumers through oral ingestion, dermal absorption and inhalation. The lifetime cancer risk and the hazard index of THMs through oral ingestion, dermal absorption, and inhalation exposure from tap water in 9 districts in Kaohsiung City are estimated. In the first part of this study, water samples were periodically collected from each treatment process of Cheng-Ching Lake Water Treatment Plant (CCLWTP) to assess the AOC (assimilable organic carbon) removal. In the second part of this study, the role of BAC filtration used in advanced water treatment plant and its capability to remove pollutants (AOC, bromide, bromate, and iron) were evaluated. Additionally, the efficiency of biofiltration process using GAC and anthracite as the fillers was also assessed with a bench-scale GAC adsorption column. In third part of the study, the distribution system of CCLWTP was selected for conducting the case study for understanding the fate and transport of water quality indicators in the distribution system. The last part of the study concentrated on undertaking multipathway exposure assessment based on the concentrations of various THMs found in the water samples collected at various locations of Kaohsiung City water supply system. The AOC removal efficiency of the advanced water treatment processes of the CCL was assessed using data collected in the field during the first phase of this study. However, the effect of two different filling materials on the efficiency of biofiltration process was evaluated using a laboratory bench-scale column study. Results of both laboratory study and field investigation show that a significant AOC removal efficiency was achieved by the BAC system implemented in CCLWTP. Conclusions of this study are summarized as follows: 1. Significant AOC removal efficiency was achieved in CCLWTP and the AOC concentrations in the effluent could meet the current established standards. 2. The increased AOC concentrations after the treatment of preozonation and chlorination may be caused by the oxidation of organic matters to more biodegradable and assimilable products. 3. The removal of AOC is correlated with the decrease in concentrations of other drinking water indicators, e.g., coliform, TPC, TDS, and particle counts). 4. The addition of sodium thiosulfate in water samples could enhance the performance of the AOC analysis (the accuracy and reliability). 5. The BAC filtration has been demonstrated to play an important role in the removal of the trace AOC. Thus, the application of BAC for AOC removal is feasible and should be included as a required treatment unit in the advanced WTP. The field study completed in the second part assessed the removal efficiencies of AOC and other water quality indicators in CCLWTP, while the effects of using two different filling materials on the efficiency of biofiltration process and microorganisms growing were evaluated using a laboratory bench-scale column study. Conclusions of this study include the following: 1. The BAC filtration system is capable of removing trace pollutants including organics and metals. 2. Significant overall treatment efficiency can be achieved in the CCLWTP, and concentrations of the water quality indicators in the effluent will meet the drinking water standards established by TEPA. 3. The increased AOC concentrations after ozonation and chlorination processes may be caused by the oxidation of organic matters into more biodegradable and assimilable organic products. 4. GAC is a more appropriate filling material than anthracite in the biofiltration system for the removal of AOC. 5. More microorganisms were observed in GAC column than in BAF column. This may be due to the effect that GAC has more specific surface area than anthracite. Additionally, more microbial growth was observed at depth of 5 cm than 0 and 40 cm in both columns indicating that 5 cm below the column surface is rich in both dissolved oxygen and biodegradable that causes higher microbial populations. 6. The BAC filtration plays an important role in the removal of the trace AOC; it should be included as a required treatment unit in future advanced WTP. Additionally, the BAF filtration column filled with anthracite is not as effective as the GAC-filled column in removing AOC. Thus, GAC should be used for the proposed BAF filtration unit. 7. The oxidation process using ozone will increase the amount of carbonyl group organics in the oxidized water leading to poor biological stability. Therefore, the oxidation should be combined with a subsequent GAC or biological process to minimize the AOC formation potential. The third study, Using the oxidation/reduction potential (ORP) along with other water quality parameters to indicate the water quality in the CCLWTP distribution systems was assessed and focused. Behavior of water quality parameters by monitor and investigate was made a replacement of corrosive pipe line. The results reveal that the treated water leaving CCLWTP (clear water) meets the drinking water standards in Taiwan. However, the water is re-contaminated by a number of factors including the corrosion of old pipes while it is flowing in the distribution system. Major conclusions of this study are summarized in the following sections: 1. The free residual chlorine concentration in CCLWTP distribution system is adequate to meet the drinking water standards established by TEPA. 2. The residual AOC concentration is well correlated with the TOC concentration in the samples collected at various sites in different administrative areas. 3. Ratios of AOC/TOC in six administrative areas were higher than 9%, indicating that the biofilms were fall and increased organic matter of tap water distribution systems. 4. The average AOC concentrations were increased with followed variations of UV-254 value. 5. A number of factors (AOC, pH, redox potential, TOC, UV-254, and chlorine residual) control the growth of microorganisms on pipe surfaces. 6. DO have a negative relationship between THMs and HAAs concentrations. Because that oxygen have higher electronegative than chlorine and bromine, and apt utilization of organic carbon. 7. Results were shown of pH, DO and ORP had a positive relationship (Need to be more specific about the correlationship. 8. Major chemical reactions in the distribution system involve both electrons and protons transfers; they are pH- and Eh (ORP)-dependent. Therefore, chemical reactions in pipe net often can be characterized by pH and Eh together with the activity of dissolved chemical species. 9. The results reveal that the non-scaling water in LSI of distribution systems of CCL close to saturation (LSI = 0) (Cannot be understood). As show the other results, located K and M1 areas in LSI¡@were -0.002 and -0.012, respectively. The appearance of the pipe in K and M1 areas were corrosion and undersaturated with CaCO3 (needs to be re-written). 10. The RSI value was between 7.0 and 7.5 showing potential corrosion and prioritizes replacement of the pipe. 11. The DO value has a correlation with the reverse in Fe and Fe3+ concentrations. 12. High oxidation conditions and elevated Fe3+ concentrations of exist inside the corrosion scales of the corroded water distribution pipes. 13. The Fe concentrations in the samples collected in various administrative areas exceed the TEPA drinking water standards. 14. The appearance of CCL distribution system of shows severe corrosive and oxidized conditions. The last part of this study concentrated on evaluating the association between trihalomethanes (THMs) exposure through three different pathways and long-term health risks. The results show that the consumer has a higher risk of cancer through Inhalation route. This is different from the results reported by other research. Because most residents living in Taiwan are accustomed to drinking boiled water, the lifetime cancer risks through oral ingestion of water-borne CHBrCl2, and CHBr2Cl in tap water in all 9 districts were higher than 10-6. By oral ingestion the lifetime cancer risk for total THMs was highest in the 7th district, while the lowest lifetime cancer risk for total THMs was in the 4th district. Chloroform poses a higher cancer risk to Kaohsiung City residents through dermal exposure than the other three THMs. This study showed that residents in 7th district had the highest cancer risk through inhalation of chloroform among the 9 districts, and the residents in 6th district had the least cancer risk. Residents in 7th district has the highest risk of cancer due to exposure of THMs during showering and bathing as compared with residents in 4th district Males have a higher cancer risk than females through dermal absorption when exposed to THMs. The results of noncarcinogenic risk assessment for THMs indicate that if the main pathways are through oral ingestion and dermal absorption, 7th district has the highest hazard index of the four chemicals, while 4th district has the lowest hazard index. According to the above results, the quality of drinking water in Kaohsiung City is in general in accordance with the guidelines for drinking water quality as recommended by the World Health Organization. A better drinking water quality can be achieved by reducing the quantity of disinfection by-products (DBPs) through the removal of DBP precursors using modified treatment practices. Coagulation, granular activated carbon, membranes and ozone-biofiltration can all remove natural organic matter. Additionally, source water protection and control are effective non-treatment alternatives to control water-borne precursors. Optimized applications of disinfectants as primary and secondary disinfectants can further be implemented to control DBPs. Although research efforts continue to develop new treatment methods that will reduce the levels of DBPs during disinfection, it is generally accepted that risks to health caused by water-borne DBPs in drinking water are relative small in comparison with risks associated with water-borne diseases due to inadequate disinfection. Thus, it is important that the disinfection process should not be compromised in attempting to control water borne DBPs. The predominant DBPs group has been shown to be THMs, with chloroform and BDCM as the most dominant THMs. Although THMs are only one subgroup of the many DBPs formed during chlorination, they are useful as indicators of the overall DBP formation. It is concluded that, given the current state of knowledge, a risk assessment based on THMs would provide the greatest level of confidence regarding the ability of a drinking water guideline to protect against risks of cancer and other long-term health hazards. In conclusion, in order to reduce the cancer risk and hazard as indexed by THM concentrations in the drinking water, some methods could be used including controlling to reduce THMs precursors and microbial contaminants in raw water, and aged pipeline, optimizing all treatment processes to ensure that concentrations of disinfectant are adequate, using alternative disinfectants and reducing water age in distribution system. The potential human risks associated with drinking water disinfection are largely unknown, even though some information is available from toxicological and epidemiological studies. More research is needed to determine the risks associated with DBPs. The next progress will facilitate a more realistic assessment of risk due to drinking water contaminants without increasing the levels of uncertainty in risk estimates.
22

Phosphorus sorption behaviour of some South African water treatment residues.

Norris, Matthew. January 2009 (has links)
Water treatment residues (WTRs), which are by-products from the production of potable water, are chemically benign, inorganic materials which are suitable for disposal by land application. Their high phosphorus (P) sorption capacities have, however, generated some concern in an agronomic context where P is recognised as a growth limiting plant nutrient. The extent to which labile P pools are reduced or enhanced by WTR amendments is, therefore, a central issue with respect to their disposal by land application. Therefore, the aim of this study was, through the use of empirical adsorption isotherm equations and chemical fractionation of P within the residues, to investigate the chemical processes responsible for the retention and release of P from 15 South African WTRs. Chemical characterisation revealed considerable variation in residue properties relevant to P sorption-desorption processes. pH, exchangeable Ca and organic carbon content ranged from 4.77 to 8.37, 238 to 8 980 mg kg-1 and 0.50 to 11.6 %, respectively. Dithionate, oxalate and pyrophosphate extractable Al fractions ranged from 741 to 96 375, 1 980 to 82 947 and 130 to 37 200 mg kg-1, respectively. Dithionate, oxalate and pyrophosphate extractable Fe ranged from 441 to 15 288, 3 865 to 140 569 and 230 to 90 000 mg kg-1 respectively. Therefore mechanisms of retention were hypothesised to be residue specific, being dependent on the unique chemical properties of the sorbent. Elevated Ca and amorphous Al and Fe concentrations did, nevertheless, suggest that all residues had the capacity to adsorb high amounts of P and to retain this P in forms unavailable for plant uptake. These arguments were confirmed by the sorption study where labile P was, for all residues, found to constitute a small fraction of total applied P even at high application concentrations (128 mg P L-1). Sequential P fractionation revealed that most of the inherent P (which ranged from 1 149 to 1 727 mg P kg-1) and applied P were retained in highly resistant mineral phases or fixed within the organic component. Thus P replenishment capacities were restricted even though residual P concentrations were often within adequate ranges for plant growth. Phosphorus adsorption data was described by four empirical adsorption isotherm equations in an effort to determine possible mechanisms of retention. Sorption data was, for most of the WTRs, described by the Temkin isotherm while the Freundlich and linear models fitted data for two residues each. A key finding was that the distribution coefficient (Kd) tended to increase with the quantity of P adsorbed (S) as opposed to decrease or remain constant in accordance with model assumptions. Therefore, the models could not be used for mechanistic interpretation, even though they provided excellent descriptions of the data. The direct relationship between Kd and S suggested a mechanism of retention involving the activation of sorption sites. This notion was supported by the fractionation study which showed that P addition results in the transfer of an increasing quantity of organically bound P to resistant residual forms. Model affinity parameters were strongly correlated to dithionate and pyrophosphate extractable Al and Fe which suggested that P was adsorbed primarily through ligand exchange mechanisms. The mobility of P bound to organic fractions did indicate that P was retained through weaker forces of attraction such as monodentate ligand exchange, charge neutralisation or proton transfer. Evidence to support the notion that P is immobilised through the formation of Ca phosphates was lacking. Based on P fractionation data, it was suggested that strong chemisorption mechanisms and the diffusion of P into WTR micropores were largely responsible for the minimal quantity of P desorbed by disequilibria desorption processes. A greater quantity of P was desorbed in the presence of oxalate and citrate which suggested that plants may increase bio-available pools through the release of organic ligands. Phosphorus desorbed in the presence of these ligands did, however, decline with P addition which confirmed that the affinity of the WTR surface for P increases with P application. Therefore, it was concluded that the application of P to WTRs is an uneconomical process unless sorption sites are already saturated or immobilisation processes are inhibited. In light of these findings, it was suggested that the absence of plant P deficiencies under the field application of WTRs is due primarily to inhibited sorption. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.
23

The effect of water treatment residues on soil microbial and related chemical properties.

Pecku, Shantel. January 2003 (has links)
Water treatment residue (WTR), a by-product of the water treatment process, consists primarily of precipitated hydroxides of the coagulants used in the water treatment process, along with sand, silt, clay, humic compounds, and dissolved organic matter. It is usually disposed of by landfill, a technology with numerous problems that include dwindling landfill capacity, extensive dewatering requirements for the WTRs, high costs of transportation, and potential liability for landfill clean-up. Therefore, land disposal (or land treatment) presents a popular alternative disposal method based on the principle that the physical, chemical, and microbial properties of the soil can be used to assimilate applied waste without inducing any negative effects on soil quality. The objective of this study was to investigate the effects of land disposal of the WTR generated by Umgeni Water, a local water treatment authority, on soil quality. These effects were investigated using depth samples from soil profiles of Westleigh and Hutton soil forms at field trials located at Ukulinga Research Farm, near Pietermartizburg and Brookdale Farm, Howick, KwaZulu-Natal, South Africa, respectively. Four rates of WTR (0, 80, 320, and 1280Mg ha-1 incorporated into the soil) were investigated at both trials, in addition to mulched treatments at rates of 320 and 1280Mg ha-1 at Brookdale only. Sampling of plots was carried out in September 2001 and May 2002, and all treatments were investigated under fallow and grassed cultivation. Laboratory measurements used to assess soil quality included pH, electrical conductivity (EC), organic carbon (QC), and microbial activity using f1uorescein diacetate (FDA) hydrolysis. At both trials in September 2001 WTR-amended plots displayed higher pH in the 0-200mm soil in comparison to the controls, whereas by May 2002 pH had returned to the condition of the controls. Addition of WTR at Ukulinga resulted in higher QC in September 2001, but in May 2002 this was similar to the controls. However, at Brookdale QC was unaffected by WTR. At Ukulinga and Brookdale the effect of WTR on EC was variable, and microbial activity in the soil profile was unaffected by WTR addition. Observations at Ukulinga and Brookdale reflected long term changes (3 and 5 years, respectively) to soil quality following WTR addition. To examine the initial changes in soil quality a laboratory experiment was set up using the field trial soils. Research objectives were also extended to include WTRs from Rand Water (Johannesburg), Midvaal Water Company (Stilfontein), Amatola Water (East London), and two samples from the Faure Water Treatment Plant (near Cape Town). The second Faure sample (Faure2 ) was collected when blue green algal problems were experienced at the plant. The measurements used to investigate these short term effects on soil quality were soil pH, EC, and microbial activity as indicated by respiration rate. Each of the WTRs added to the Hutton and Westleigh soils increased soil pH by varying increments, and the higher the WTR application rate, the higher was the pH recorded. With the exception of the Rand and Umgeni WTRs that clearly increased soil EC, the effect of the otherWTRs on EC was variable. The Faure1 and Amatola WTRs appeared to have no effect on microbial activity, whereas the Umgeni, Rand, Midvaal, and Faure2 WTRs stimulated microbial activity by Day 2 following the addition of WTR, but this had declined by Day 14. As for pH, higher microbial activity was recorded at higher WTR application rates. Changes in microbial community structure of the Hutton soil only, following the addition of WTR were examined using denaturing gradient gel electrophoresis (DGGE) analysis. Community profiles of the different WTRs proved to be markedly different. However, WTR-amended soil retained banding patterns consistent with the control soil indicating that dominant populations in the Hutton soil had been retained. The field trials indicated that long term effects of land disposal of WTR were not detrimental to the measured indicators of soil quality namely, pH, EC, QC, and microbial activity. The laboratory assessments of the short term response of the Hutton and Westleigh soil forms to WTR addition suggested that the tested variables were altered by WTR, but not significantly changed to the detriment of soil quality. Microbial community analysis indicated that the community structure of the Hutton soil was not significantly altered by WTR amendments. Present findings provide no evidence to suggest that land disposal of WTR is detrimental to soil quality. It is therefore regarded as a feasible disposal option although there are some aspects that should be investigated further. These include investigations into rhizosphere/microbial interactions and the feasibility of growing cash crops. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
24

Avaliação do uso de geossintético para o deságue e geocontenção de resíduos sólidos de estação de tratamento de água / Evaluation of the use of geotextile tubes for dehydrating and retaining slurry from a water treatment plant

Pieper, Karla Maria Cypriano January 2008 (has links)
O presente trabalho tem por objetivo avaliar a técnica de desaguamento de resíduos sólidos gerados em estações de tratamento de água utilizando tubos geotêxteis - Bags, que representam uma alternativa tecnológica para a redução do teor de umidade dos resíduos. O trabalho foi dividido em duas etapas: ensaios com Bags suspensos e com Bags dispostos sobre o solo. Nos estudos são abordadas as características mais relevantes do processo de desaguamento face às solicitações mecânicas e hidráulicas a que qualquer sistema está submetido, bem como são apresentados resultados e discussões sobre as características físico-químicas dos resíduos gerados, geocondicionados nos Bags geotêxteis e da água drenada. A técnica de desaguamento por Bags mostrou-se uma alternativa viável para a redução do teor de umidade, apresentando um melhor desempenho em relação às técnicas convencionais. Pode-se também utilizá-la em paralelo com outras técnicas já existentes para a otimização do processo de desaguamento. Ressalta-se que a correta operação da tecnologia garante a eficiência da drenagem, sendo, então, necessária a adição de polímeros como agentes coagulantes, de forma a promover a separação da fase líquida da fase sólida. Observou-se que os resíduos geocondicionados ao reduzirem o teor de umidade passam a concentrar alguns componentes químicos tais como: sílica, nitrogênio e alumínio. As dificuldades relacionadas à disposição de resíduos sólidos em estações de tratamento de água justificam esse estudo. A despeito dos resultados satisfatórios desse estudo, é importante salientar a necessidade de mais projetos que avaliem os resultados obtidos nos ensaios e o comportamento dos Bags com o passar do tempo, já que a técnica mostrou-se viável ambiental, econômica e tecnicamente. / The present study aims at evaluating the disposal process of slurry from a water treatment plant. In replacement to the conventional technique of disposing slurry in pools, a geotextile tube has been used to dehydrate and retain the slurry inside the Bag. This is achieved because the geotextile is permeable, yet soil-tight, and any excess water pressure is expelled from the tube. The work has been divided in two sets of tests: suspended Bags to define a treatment methodology and a prototype geoBag laid on the ground over a drained layer to simulate the treatment process. The mechanical, hydraulic and chemical responses associated with this process considering both solid waste and drained water contents have been evaluated and discussed. As a whole, the use of geoBags has proved to be a viable option to reduce the water content in slurry, as well as an attractive alternative to replace or to be combined with other techniques currently in use in Brazil. A critical aspect controlling the efficiency of the operation is the addition of polymers for flocculation before introducing slurry into the Bag so that liquid and solid phases are dissociated. Upon monitoring the process, it has been observed that solids retained inside the Bag exhibit concentrated levels of chemical components such as silica, nitrogen and aluminum. This study has been considered relevant in face of the environmental needs and public policy control of the disposal of solid wastes. In spite of being a promising alternative technique to slurry treatment, further investigation is needed to evaluate the trials results of this research and bag behavior as time goes by. So far, the technique has proved to be environmentally, economically and technically feasible.
25

Avaliação do uso de geossintético para o deságue e geocontenção de resíduos sólidos de estação de tratamento de água / Evaluation of the use of geotextile tubes for dehydrating and retaining slurry from a water treatment plant

Pieper, Karla Maria Cypriano January 2008 (has links)
O presente trabalho tem por objetivo avaliar a técnica de desaguamento de resíduos sólidos gerados em estações de tratamento de água utilizando tubos geotêxteis - Bags, que representam uma alternativa tecnológica para a redução do teor de umidade dos resíduos. O trabalho foi dividido em duas etapas: ensaios com Bags suspensos e com Bags dispostos sobre o solo. Nos estudos são abordadas as características mais relevantes do processo de desaguamento face às solicitações mecânicas e hidráulicas a que qualquer sistema está submetido, bem como são apresentados resultados e discussões sobre as características físico-químicas dos resíduos gerados, geocondicionados nos Bags geotêxteis e da água drenada. A técnica de desaguamento por Bags mostrou-se uma alternativa viável para a redução do teor de umidade, apresentando um melhor desempenho em relação às técnicas convencionais. Pode-se também utilizá-la em paralelo com outras técnicas já existentes para a otimização do processo de desaguamento. Ressalta-se que a correta operação da tecnologia garante a eficiência da drenagem, sendo, então, necessária a adição de polímeros como agentes coagulantes, de forma a promover a separação da fase líquida da fase sólida. Observou-se que os resíduos geocondicionados ao reduzirem o teor de umidade passam a concentrar alguns componentes químicos tais como: sílica, nitrogênio e alumínio. As dificuldades relacionadas à disposição de resíduos sólidos em estações de tratamento de água justificam esse estudo. A despeito dos resultados satisfatórios desse estudo, é importante salientar a necessidade de mais projetos que avaliem os resultados obtidos nos ensaios e o comportamento dos Bags com o passar do tempo, já que a técnica mostrou-se viável ambiental, econômica e tecnicamente. / The present study aims at evaluating the disposal process of slurry from a water treatment plant. In replacement to the conventional technique of disposing slurry in pools, a geotextile tube has been used to dehydrate and retain the slurry inside the Bag. This is achieved because the geotextile is permeable, yet soil-tight, and any excess water pressure is expelled from the tube. The work has been divided in two sets of tests: suspended Bags to define a treatment methodology and a prototype geoBag laid on the ground over a drained layer to simulate the treatment process. The mechanical, hydraulic and chemical responses associated with this process considering both solid waste and drained water contents have been evaluated and discussed. As a whole, the use of geoBags has proved to be a viable option to reduce the water content in slurry, as well as an attractive alternative to replace or to be combined with other techniques currently in use in Brazil. A critical aspect controlling the efficiency of the operation is the addition of polymers for flocculation before introducing slurry into the Bag so that liquid and solid phases are dissociated. Upon monitoring the process, it has been observed that solids retained inside the Bag exhibit concentrated levels of chemical components such as silica, nitrogen and aluminum. This study has been considered relevant in face of the environmental needs and public policy control of the disposal of solid wastes. In spite of being a promising alternative technique to slurry treatment, further investigation is needed to evaluate the trials results of this research and bag behavior as time goes by. So far, the technique has proved to be environmentally, economically and technically feasible.
26

Avaliação da disposição de lodo gerado numa estação de tratamento de água em reator anaeróbio de fluxo ascendente e manto de lodo UASB. / Evaluation of throwing sludge generated on a treatment water station with an upflow anaerobic sludge blank reactor (UASB).

Carlos Gonzalo Alvarez Rosario 13 March 2007 (has links)
As estações de tratamento de água de abastecimento (ETAs) têm a finalidade de fornecer água potável. Neste processo de tratamento de água são gerados resíduos, os quais historicamente têm sido lançados em cursos de água, aumentando o nível de degradação destes. O presente trabalho teve por objetivo avaliar o impacto do lançamento desses resíduos numa estação de tratamento de esgoto (ETE) com reator anaeróbio de fluxo ascendente e manto de lodo (UASB), buscando estudar uma alternativa para a disposição adequada desses resíduos. Para o estudo da influência do lançamento do lodo da ETA em um reator de fluxo ascendente e manto de lodo (UASB) foram utilizados dois reatores em escala piloto. O esgoto utilizado para alimentar o sistema de tratamento foi proveniente do Conjunto Residencial da Universidade de São Paulo, já o lodo utilizado foi obtido na ETA da cidade de Juquitiba. A presente pesquisa foi dividida em três fases: a primeira etapa (Fase 1) constituiu-se na partida dos reatores UASB 1 e UASB 2; na segunda etapa (Fase 2) estudou-se o desempenho dos sistemas sob regime estabilizado; e na terceira e última etapa (Fase 3) o reator UASB 2 recebeu adição de duas dosagens de lodo de ETA, sendo a primeira de 50 mg/L (Fase 3a) e a segunda de 75 mg/L (Fase 3b), em termos de sólidos em suspensão totais. As condições operacionais adotadas foram: vazão de 50 L/h e tempo de detenção hidráulico (TDH) de 8 horas. Os resultados apresentados no texto indicaram que, com o acréscimo de lodo da ETA, o reator UASB 2 não teve seu desempenho afetado negativamente, e a remoção de matéria orgânica em termos de DQO, DBO e fósforo foi muito próxima entre os reatores UASB 1 e UASB 2. Conclui-se que com a disposição de lodo em um reator UASB, não haverá interferência prejudicial no desempenho operacional do mesmo. / Water treatment stations have the purpose of providing potable water. In this process of water treatment, a variety of residuals are produced; these, historically have been discharged into water streams, increasing the water pollution. The objective of this work was to evaluate the impact of discharging residuals in a treatment station with an Upflow Anaerobic Sludge Blank Reactor (UASB), and try to find an alternative for the appropriate treatment of these. For the study of the influence of discharging WTA sludge into a UASB reactor, two reactors in pilot scale were used. The disposals used to feed the treatment system came from the apartment building where Sao Paulo University students live, while the sludge used was obtained in the water treatment station from Juquitiba city. This research has been divided into three stages: The first one (Stage 1) consisted of the setting of the reactors UASB1 and UASB2. In the second stage (Stage 2) it was studied the performance of the systems in the balance regime. In the third one (Stage 3), the reactor UASB2 received the supply of two portions of WTA sludge, the first one of 50 mg/L (Stage 3a) and the second one of 75 mg/L (Stage 3b). These amounts are determined in terms of the TSS. The operational conditions adopted were flow of 50 L/h and TDH of eight hours. The results obtained indicated that with the addition of WTA sludge the reactor UASB2 did not show inferior performance. At the same time the organic material removal, in terms of DQO, DBO and phosphorous content, was similar between the reactors UASB1 and UASB2, concluding that with the supply of WTP sludge in the reactor UASB, there won\'t he detrimental effects in the reactor performance.
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Estudo de reuso e reciclagem de agua de lavagem de filtro rapido de estação de tratamento de agua, em sistema de ciclo fechado, independente / Study of reuse and recycling of rapid filter backwash water from water treatment plant in independent close cycle system

Reis, Jose Roberto Bezerra dos 09 November 2009 (has links)
Orientador: Ruben Bresaola Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-14T17:21:03Z (GMT). No. of bitstreams: 1 Reis_JoseRobertoBezerrados_M.pdf: 4806731 bytes, checksum: f4634921271dbf74dd3233925df387a5 (MD5) Previous issue date: 2009 / Resumo: O projeto foi desenvolvido visando estudar o tratamento e o reuso da água de lavagem de filtro para reciclagem nesta função, dentro de um circuito fechado, em sistema independente das atividades de produção de uma estação de tratamento de água de abastecimento. O sistema foi dotado de unidade de mistura de polímero, pré-filtro de pedregulho e filtro de dupla camada (F3), semelhante aos usados na estação de tratamento de água. O pré-filtro foi retirado do sistema porque não forneceu a eficiência esperada. Com esta disposição foi monitorado o número de vezes que a água obtida poderia ser reutilizada sem influir na qualidade da água de início de filtração do filtro piloto F1, o que mostrou ser maior ou igual cinco vezes. A perda da água de lavagem no sistema foi de 0,13%, bastante significativo perante os valores costumeiros de 2 a 5%. O sistema operou sempre com partículas floculentas, nunca com partículas coloidais. / Abstract: The project was developed with the aim of studying the treatment and the reuse of rapid filter backwash water for recycling in this role, within a closed cycle, under system independent of production activities of a water treatment plant. The system was assembled with a polymer blending unit, a gravel preliminary upflow filter and a dual layer filter(F3), similar to those used in the water treatment plant. The pre-filter was withdrawn because it did not provided the expected efficiency. With this provision, it was monitored the number of times that water obtained could be reused without affecting the quality of water filtration top of the filter F1 which proved to be greater or equal to five times. The loss of filter backwash water in the system was 0,13%, quite significant when compared to the usual 2 to 5%. The system always worked with flocculent particles, not with colloidal particles. / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil
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Avaliação do impacto de lodos de estações de tratamento de água à biota aquática através de estudos ecotoxicológicos / Evaluation of the impact of sludges from water treatment plants on the aquatic biota using ecotoxicological studies

Rosana Maria Barbosa 26 June 2000 (has links)
Lodos de duas Estações de Tratamento de Água (ETA) que utilizam cloreto férrico (ETA-Paiol-ETA-1) e sulfato de alumínio (ETA-SAAE-ETA-2) como coagulantes, foram caracterizados físico-quimicamente em duas estações do ano (chuvosa e seca) e submetidos a testes de toxicidade aguda com microcrustáceos (Daphnia similis), quironomídeos (Chironomus xanthus) e peixes (Hyphessobrycon eques) e de toxicidade crônica com microcrustáceos (D. similis). Observou-se ainda os efeitos destes lodos na comunidade bentônica dos corpos d\'água que recebem os lançamentos das ETAs. Os efeitos dos lodos nos testes de toxicidade aguda foram observados em relação a mortalidade, e, quanto aos testes de toxicidade crônica, observou-se os efeitos na reprodução (número de neonatas) e na mortalidade. Em geral, os lodos das duas ETAs não causaram toxicidade aguda aos organismos-teste, ocorrendo apenas indícios de toxicidade. O lodo da ETA que utilizava cloreto férrico causou toxicidade crônica, que foi observada na reprodução (baixo número de neonatas) e na alta taxa de mortalidade, enquanto que o lodo da ETA que utilizava sulfato de alumínio causou toxicidade crônica evidenciada apenas em relação a reprodução. Os lodos causaram efeitos adversos à fauna bentônica, evidenciados pela predominância de Diptera nos pontos de lançamento das ETAs nos corpos receptores. Constatou-se ainda a variação temporal na caracterização dos lodos em relação aos parâmetros: pH, turbidez, série de sólidos, nutrientes (N e P) e metais (AI, Mn e Fe), sendo que estes, juntamente com a DQO, foram identificados como os principais parâmetros que aumentam a degradação dos corpos receptores que recebem os lançamentos dos efluentes das ETAs. Portanto, a disposição \"in natura\" dos efluentes das ETAs prejudica à biota aquática e compromete a qualidade da água e do sedimento dos corpos receptores. / Sludges from two water treatment plants, which use ferric chloride (ETA-Paiol-ETA-1) and alum (ETA-SAAE-ETA-2) as coagulants were characterized physicall y and chemically at two seasons (wet and dry). The sludge was subjected to acute toxicity tests to cladoceran (Daphnis similis), midges (Chironomus xanthus) and fishes (Hyphessobrycon eques) and chronic toxicity tests using clacloceran (D. similis). It also was observed the impact of discharged sludge on benthic communities in surface waters at two water treatment plants. Acute toxicity tests evaluated sludge effects on mortality, while chronic toxicity tests assessed effects on reproduction and mortality. In general, sludges from two water treatment plants did not show acute toxicity on organisms-test, only toxicity traces. Ferric chloride sludge showed chronic toxicity on lower brood production and high mortality rate. Alum sludge showed chronic toxicity only on brood production. Sludges from water treatment plants caused detrimental effects to benthic macroinvertebrate communities. This effect was determined by Diptera predominance at bodies receiving discharge from water treatment plants. The turbidity, solids series, nutrients (N and P) and metals (Al, Mn and Fe) in the sludge vary when experiments are carried out in the dry and wet season. Together with COD, there were the main parameters that cause the increase in degradation of bodies receiving discharge from water treatment plants. Thus the disposal of \"in natura\" effluents from water treatment plants damages aquatic biota and affects receiving bodies water and sediment quality.
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Análise de viabilidade da utilização de lodo de ETA coagulado com cloreto de polialumínio (PAC) composto com areia como agregado miúdo em concreto para recomposição de calçadas: estudo de caso na ETA do município de Mirassol-SP / Viability analysis of water treatment plant sludge coagulated with aluminum polychloride used as small aggregate associated with sand in concrete for pavements recomposition: case of study in water treatment plant of Mirassol-SP

Álvaro José Calheiros da Costa 25 February 2011 (has links)
O presente trabalho foi elaborado com o intuito de equacionar dois problemas: redução do impacto ambiental do lançamento do lodo da ETA Mirassol in naturanos córregos e a redução de custos através da redução na quantidade de lodo enviada para o aterro sanitário e da redução no volume do agregado miúdo o qual, apesar de não representar o maior custo entre os materiais necessários para a confecção do concreto, representa uma redução de custos para a empresa concessionária que precisa recompor diariamente as calçadas que são quebradas para a execução de seus serviços de manutenção nos sistemas de água e esgoto. Devido ao fato de a ETA Mirassol ainda não dispor de um plano de gerenciamento dos resíduos de seu tratamento, como metodologia de secagem das amostras de lodo, optou-se pela simulação de lagoa de lodo fora de escala em que o lodo ficou exposto ao sol durante períodos diferentes de 15 e 30 dias. A primeira amostra, mais seca, foi utilizada nos ensaios de lixiviação e solubilização e a segunda nos ensaios envolvendo o concreto. Foram realizados ensaios de lixiviação e solubilização com o objetivo de classificar o lodo de acordo com a ABNT NBR 10.004/2004 os quais, resultaram em excesso nos teores de cádmio, chumbo e, principalmente, de manganês, cerca de 400 vezes maior que o permitido. Por conta disto, o lodo pôde ser classificado como um resíduo classe II A, ou seja, não perigoso e não inerte. Vale destacar que apesar de coagulado com policloreto de alumínio, o lodo não apresentou teores deste metal que superassem os limites da norma. Voltando a atenção para o concreto de calçada, verificou-se que não existem normas ou padrões que determinem a maneira adequada de executá-Io. Desta forma, optou-se por simular a confecção do concreto realizada no dia-a-dia pelos pedreiros, compreendendo o traço 1:2:3 (cimento:areia:brita) em massa e com o acompanhamento visual da sua trabalhabilidade. A análise de viabilidade da utilização do lodo como agregado foi realizada com base nos ensaios de compressão axial e compressão diametral, também conhecido como ensaio brasileiro (tração). Estes ensaios demonstraram que para os traços que utilizam 5%, 10% e 20% de lodo, foram obtidas resistências à compressão axial superiores à meta de 15 MPa o que foi considerado bastante satisfatório uma vez que são recomendados para calçadas valores de 10 MPa. Já para os ensaios de tração, não há referências, mas pôde-se constatar que a utilização do lodo como composto com areia como agregado miúdo interfere sensivelmente nos resultados, sendo recomendada a utilização de porcentagens próximas a 10%. Portanto, concluiu-se que a utilização do lodo da ETA Mirassol em concretos para recomposição de calçadas é viável nas porcentagens até 10%. / This work was done wishing to solve two problems: the reduction of the environmental impact caused by the inappropriate sludge disposal in Mirassol and also the reduction in the costs by reducing the volume of sludge destined to landfill and by reducing the volume of concrete small aggregates which, in spite of not representing the biggest cost of all materials involved, actually represents a cost reduction to the concessionary which needs to remake daily the pavement broke to the execution of maintenance and operation works in the water and wastewater systems. Considering the fact that Mirassol\'s water treatment plant does not have a sludge management plan, it was chosen the sun exposal method with two different times (15 and 30 days) to dry the samples of sludge. The first sample, the driest, was used in the lixiviation and solubilization experiments and the second one in the experiments involving the concrete. The objective of lixiviation and solubilization experiments was to classify the sludge according to ABNT NBR 10.004/2004. This experiments resulted manganese, plumbean and cadmium excess, especially the manganese with 400 times more concentration than the permitted by the law. So, according to these results, Mirassol\'s water treatment plant sludge was classified as Class II A. That\'s important to observe that, despite the fact that in Mirassol they use the CPA, the sludge did not shown high concentrations of aluminum. Keeping the attention on the concrete to pavements, it was noticed that doesn\'t exist in Brazil any law to discipline its confection and because of that, it was chosen the empirical method, used by the workers daily with 1:2:3 in mass. The viability analysis of the sludge use as aggregate to concrete pavement was based on the compression and traction experiments which demonstrated that, considering traces with 5%, 10% and 20% of sludge incorporated, the results was satisfactory. In fact, all of the samples had results above the aim for compression (15 MPa). On the other hand, considering the traction experiments, there\'s no references in Brazil for pavements, but it was possible to observe that the sludge addiction affected more this characteristic than the compression. However, the traction results were also satisfactory. Finally, this work recommends the utilization of 10% of sludge incorporated in concrete to pavements because they had the best results considering the compression and traction experiments.
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Disposição de resíduos gerados em estações de tratamento de água em estações de tratamento de esgoto / Disposal of water treatment plants sludge in wastewater treatment plants

Paulo Sergio Scalize 08 August 2003 (has links)
O presente trabalho foi realizado em duas fases. Na primeira, foram estimados os efeitos produzidos nos decantadores primários de uma ETE, após receber resíduo da ETA-SC, que utiliza sulfato de alumínio como coagulante. Foram realizados ensaios em colunas de sedimentação, onde os parâmetros SST, SSV, cor, turbidez, DQO, coliformes totais, Escherichia coli e parasitas, pesquisados no sobrenadante, diminuíram com o aumento da quantidade de resíduo adicionado. Com relação aos sedimentos obtidos nas colunas de sedimentação, foi encontrada maior quantidade de ST e menor resistência específica nos lodos provenientes das colunas que receberam os resíduos da ETA-SC. No teste de atividade metanogênica, a concentração molar de metano foi reduzida nos sistemas que receberam resíduo da ETA-SC, influenciando negativamente no desenvolvimento dos microrganismos metanogênicas. As espécies de microrganismos do gênero Methanothrix sp foram inibidas, sendo encontradas em maior número no frasco-reator controle e em menor quantidade a medida que se aumentou a quantidade do resíduo adicionado. Nesta etapa foi constatado que o resíduo da ETA-SC poderá apresentar interferências negativas sobre a digestão anaeróbia do lodo produzido em decantadores primários de uma ETE. Na segunda fase, na estação piloto, composta de lagoa de aeração seguida de lagoa de sedimentação, que recebeu resíduo da ETA-Fonte, que utiliza cloreto férrico como coagulante, foi verificado que tal resíduo melhorou a qualidade do efluente em termos de DQO, DBO, SST, turbidez, cor, amônio, nitrato, NTK e fosfato total. Os parâmetros ST, SDT, cloreto, nitrito, condutividade e pH não apresentaram diferenças significativas. Em relação ao exame microscópico não houve influências negativas no licor misto das lagoas de aeração. O lodo formado nas lagoas de sedimentação piloto apresentou-se em maior quantidade na lagoa que recebeu resíduo da ETA-Fonte. Neste lodo a resistência específica a filtração foi menor em comparação ao lodo da lagoa que não recebeu resíduo da ETA-Fonte. A desidratação deste lodo por centrifugação necessitou menor quantidade de polieletrólito. Baseado neste estudo não foi verificado interferências que possa impedir o lançamento do resíduo da ETA-Fonte na ETE-Araraquara. / This work was carried out in two phases. Effects of disposing the residues from a water treatment plant - ETASC, which uses alum as primary coagulant on the primary settling tanks was evaluated in the first one. Sedimentation tests using column indicated that parameters such as TSS, VSS, colour, turbidity, COD, total coliformes totais, Escherichia coli e parasites in the supernatant decreased with the increase of the amount of the water treatment wastes added to the column. With relation to the sediments produced in the column, it was found great amount of TS and lower specific solids resistance in those generated in the columns where the water treatment plant residues-WTPR were used. Molar concentration of methane was reduced in the tests performed with the sediments produced with water treatment plant residues and thus, altering negatively the development of methanogenic organisms. The growth of species of microorganism of genera Methanothrix sp was inhibited, which were found in great number in the control flask (with out WTPR) and in lower number as it was increased the amount of WTPR added to the column. It was observed that the WTPR generated in the city water treatment plant may interfere in the anaerobic digestion of sludge produced in primary settling tanks of a wastetreatment plant. A continuous pilot plant was operated in the second phase, which consisted of two aerated lagoon each one followed by a settling lagoon. Waste and WTPR from a watter treatment plant which ferric chloride were fed in one of the systems. It was observed that the use of WTPR improved the effluent quality of the settling lagoon evaluated in terms of COD, BOD, TSS, turbidity, color, ammonium, nitrate, TKN and total phosphate. Some parameters, such as TS, TDS, chloride, nitride, conductivity and pH did not present significant differences in both systems. Microscopic examinations indicated that no influence resulted in the aerated lagoon mixed liquor. A higher amount of sludge was formed in the lagoon system which received the WTPR. The specific resistance to filtration of this sludge was lower than that formed in the lagoon system with out WTPR addition. When dewatering both sludges, that one produced with the addition of WTPR required less amount of polymer. It was concluded that the WTPR produced in the water treatment plant of Araraquara may be disposed in the city wastewater treatment plant.

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