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Plant growth and nutrient removal in simulated secondary-treated municipal wastewater in wetland microcosmosZhang, Zhenhua January 2008 (has links)
[Truncated abstract] The use of constructed wetlands for tertiary purification of municipal wastewater has received increasing attention around the world because direct discharge of secondary-treated municipal wastewater to water bodies has caused eutrophication. Plant species selection and vegetation management may enhance nutrient removal efficiency in constructed wetlands. However, there is a lack of knowledge on the relations between plant growth and nutrient removal efficiency in constructed wetlands. The objective of this study is to better understand how plant growth and resource allocation are influenced by nutrients in wastewater and how nutrient removal efficiencies are affected by plant species and vegetation management. The preliminary experiment was conducted to select macrophytes, especially ornamental species, to grow in the wastewater in the wetland microcosms. Ten plant species, comprising six ornamental species: Alocasia macrorrhiza, Canna indica, Iris louisiana, Lythrum sp., Zantedeschia aethiopica, Zantedeschia sp., and four sedge species: Baumea articulate, Baumea juncea, Carex tereticaulis and Schoenoplectus validus, were planted in the wetland microcosms and fed a simulated wastewater solution in the concentrations similar to the secondary-treated municipal wastewater. C. indica has shown vigorous and healthy growth, and a relatively high potential of rooting-zone aeration and nutrient removal efficiency. B. articulata and S. validus also showed relatively high nutrient removal efficiency. ... The high nutrient availability and optimum N/P ratio were required for stimulating plant growth, resulting in allocation of more resources to above-ground tissues compared to below-ground parts, and enhancing nutrient removal efficiency. Nutrient removal efficiencies were significantly influenced by growth of C. indica and S. validus, nutrient loading rates and N/P ratios in the wastewater. The nutrient uptake kinetics of C. indica and S. validus were investigated to elucidate the differences in nutrient uptake between species. Wetland plant species have shown differential nutrient uptake efficiency and different preferences for inorganic N source, with C. indica preferring NO3-N and S. validus preferring NH4-N. C. indica had greater capacity than S. validus to take up PO4-P when the concentration of PO4-P in the solution was relatively low, whereas S. validus was more capable than C. indica to take up NO3-N when the concentration of NO3-N in the solution was relatively low. The PO4-P uptake capacity was higher in younger than older plants. Overall, the study has suggested that different plant species have differential capacity to take up nutrients. In addition to nutrient uptake, plants have significant other roles in terms of nutrient removal from the wastewater (such as leaking oxygen into the rhizosphere in which oxidation of substances like ammonia can occur). The properly high nutrient availability and optimum N/P ratio are required to stimulate the plant growth, resulting in enhancing the treatment performance in the wetlands. These findings have important implications for improving our ability to engineer ecological solutions to the problems associated with nutrient-rich wastewater.
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Evaluación y gestión del riesgo asociado a la reutilización de aguas residualesAlcalde Sanz, Laura 15 June 2012 (has links)
La reutilización de aguas residuales comporta una serie de beneficios pero también conlleva un riesgo asociado a nivel sanitario y medioambiental debido a los componentes que puedan estar presentes en el agua residual, como microorganismos patógenos y contaminantes químicos tóxicos. Este riesgo asociado se ha de controlar para poder reutilizar el agua de la manera más segura posible. En este trabajo se evaluó la efectividad de diferentes tecnologías de regeneración (infiltración-percolación, fisicoquímico, filtro de anillas, dióxido de cloro, ácido peracético y radiación ultravioleta) y se establecieron las líneas de tratamiento más adecuadas para cumplir con los criterios de calidad establecidos por el RD 1620/2007 sobre reutilización de aguas residuales. También se evaluó un sistema de reutilización utilizado para el riego de un parque, considerando la EDAR, la ERA, el sistema de almacenamiento y la red de distribución hasta el punto de uso final del agua regenerada. Se estableció el comportamiento de diferentes parámetros microbiológicos y fisicoquímicos en cada etapa y las variaciones de calidad del agua regenerada a su paso por el sistema. Se realizó una evaluación cuantitativa del riesgo microbiológico (QMRA) asociado al riego del parque con agua regenerada, utilizando los patógenos de referencia de la OMS (Campylobacter, rotavirus y Cryptosporidium), concluyendo que el nivel de riesgo cumple con el nivel aceptable establecido. También se evaluó la influencia del riego con agua regenerada en las matrices ambientales suelo y agua subterránea, concluyéndose que, en el espacio de tiempo evaluado, no se aprecia una variación de la calidad fisicoquímica de estas matrices debido al riego. Por último, se aplicó un protocolo de análisis de peligros y puntos de control críticos (APPCC) en el sistema de reutilización, tal y como recomienda la OMS para gestionar el riesgo asociado a la reutilización de aguas. La aplicación de este protocolo permitió identificar los puntos de control críticos del sistema, recomendar límites críticos para cada punto y establecer medidas correctoras para las posibles desviaciones de estos límites. / Wastewater reuse provides an additional source of water resources, but there is a health and environmental risk associated with the use of reclaimed water, due to the potential presence of pathogens and toxic chemicals. These risks have to be controlled in order to be able to use reclaimed water in a safety way. In this work, several reclamation technologies have been evaluated (infiltration-percolation, physicochemical, chlorine dioxide, peracetic acid and ultraviolet radiation) to establish treatment lines that comply with the quality criteria of the national regulation RD 1620/2007 on wastewater reuse. A reuse system for the irrigation of a green area was evaluated, including the WWTP, the RWTP, the storage system and the distribution system to the irrigation place. Several microbial organisms and physicochemical parameters were monitored in each component to evaluate the variations on the reclaimed water along the system. A quantitative microbiological risk assessment (QMRA) was performed, using a computer model, in order to evaluate the risk associated to the green area irrigation, considering the three pathogens recommended by the WHO (Campylobacter, rotavirus and Cryptosporidium), resulting on the risk level complying with the acceptable level established. The environmental matrixes soil and groundwater were evaluated to determine any variation in the physicochemical quality due to the irrigation with reclaimed water, concluding that, for the time period of the study, there is not a significant variation. A hazard analysis and critical control point protocol was applied to the reuse system evaluated, as recommended by the WHO for risk management in water reuse. This protocol allowed establishing the critical control points of the system, the critical limits for each point and the corrective measures in case of deviation from the operational parameters.
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Aigua regenerada: noves estratègies en la gestió de riscos microbiològicsAgulló i Barceló, Miriam 03 May 2013 (has links)
L’aigua és un bé escàs i finit, i degut a factors com l’increment de la població i el canvi climàtic, les previsions indiquen que a mig termini un 40% de la població viurà amb un estès hídric significatiu. Això podria tenir efectes molt greus en el desenvolupament i en el benestar a les àrees afectades. És normal doncs, que els darrers anys hagi acrescut considerablement l’interès en l’obtenció de recursos hídrics alternatius i sostenibles com la regeneració d’aigua i la reutilització.
Els avenços tecnològics per al tractament d’aigües estan fent possible l’obtenció d’aigua regenerada de qualitat que pot ser utilitzada per a restauració ambiental, per al reg en general i per a usos urbans no potables. Tot i així, aquesta activitat podria suposar un perill per la presència de patògens d’origen entèric (bacteris, virus i protozous) i també per la presència de microcontaminants com productes farmacèutics, hormones o subproductes de desinfecció.
El RD 1620/2007 estableix el marc legal de la reutilització, i es basa en E. coli com a indicador de qualitat microbiològica de l’aigua regenerada (AR). Tot i així, E. coli pot no ser suficient en relació a la presència de patògens vírics o protozous. Un exemple és Cryptosporidium, que s’ha convertit en un patogen de referència ja que ha causat nombrosos brots de criptosporidiosi d’origen hídric. L’ús de microorganismes indicadors alternatius com bacteriòfags (SOMCPH o FRNAPH) o espores de clostridis reductors del sulfit (SRC), pot ser molt útil per a indicar la presència o per modelar el comportament de patògens vírics o de protozous.
En aquesta tesi s’estudia d’una banda, la qualitat microbiològica de l’AR que produeixen cinc plantes de tractament, analitzant E. coli, indicadors alternatius, i Cryptosporidium com a patogen de referència. Es fan assajos de QMRA lligats a Cryptosporidium en les EDARs estudiades, i finalment s’estudien les implicacions, d’un procés de reutilització per a augmentar el cabal del riu Llobregat uns Km més a munt del punt de captació de la potabilitzadora.
Els resultats d’aquesta part indiquen que la reutilització per a potabilització en l’escenari estudiat, no hauria de suposar cap risc per a la salut de les persones des de la perspectiva de les malalties infeccioses. S’observa que l’ús d’un altre indicador, a part d’E. coli, significaria una millora en la gestió de l’AR ja que permetria fer un seguiment molt més acurat tant de la qualitat de l’aigua com de l’eficiència dels diferents tractaments. És recomanable l’ús de tractaments multibarrera durant la regeneració per poder garantir una aigua segura, i en aquest sentit, la inclusió de llum UV és vital en la prevenció del risc associat a Cryptosporidium en AR.
D’altra banda s’estudien processos fotocatalítics d’oxidació avançada (POAs) com a processos de regeneració en l’eliminació de microorganismes d’efluents secundaris reals. D’una banda, amb l’ús de làmpades d’UV i de l’altra amb l’ús de la radiació solar com a font de llum UV. Per fer-ho es va analitzar la inactivació de diferents indicadors (SOMCPH, FRNAPH, CB390PH i SRC) davant alguns POA: H2O2/UV, TiO2/UV i foto-Fenton.
Els resultats indiquen que l’ús de POA té un gran potencial com a tractaments terciaris en el futur, especialment si estan basats en la radiació solar, ja que podrien ser una opció ambientalment sostenible i alhora eficaç en el tractament d’aigua. Tot i així, és necessari segui investigant la possible aplicació d’aquestes tecnologies ja que encara hi ha certes limitacions que fan que de moment no es facin servir de manera més estesa. Finalment, els resultats pel que fa a la inactivació de microorganismes ratifiquen que l’ús d’un altre indicador seria útil per assegura la qualitat microbiològica de l’aigua. / Population growth and climate change may worsen the current water scarcity problems, which could have serious effects on the development and on the public health of the affected areas. Therefore, there is an increasing interest in the improvement of sustainable water resources such as water reclamation. Technological advances in water treatment are making it possible to obtain reclaimed water (RW), which can be used for instance, for environmental restoration or for irrigation. However, water reuse may represent a health risk due to the presence of enteric pathogens or micropollutants.
Spanish regulations on RW are based on E. coli, but it may not be useful to protect against viral o protozoan diseases. Cryptosporidium has become a reference pathogen since it has caused numerous waterborne outbreaks. Thus, the use of alternative indicators such as somatic coliphages (SOMCPH) or spores of sulphite reducing clostridia (SRC) may be better to monitor presence and behaviour of certain pathogens.
The aims of this thesis were: (i) to study the microbiological quality of RW analysing Cryptosporidium as the reference pathogen and different microbial indicators such as E. coli, SOMCPH and SRC; (ii) to perform QMRA analysis related to the presence of Cryptosporidium in RW; (iii) to analyse the implications of planned-IPR (indirect potable reuse) in the Llobregat River; (iv) to test the effect of different AOP (advanced oxidation processes) on indicator microorganisms for water reclamation purposes.
From the infectious diseases point of view, the health risks due to waterborne pathogens linked to planned-IPR in the Llobregat River can be safely managed. Furthermore, the use of another indicator, besides E. coli, would improve RW management. Multi-barrier systems including UV for water treatment are recommended to ensure RW quality, especially with regard to Cryptosporidium inactivation.
AOPs have a great potential for water reclamation in the future, especially those based on solar light, because they are sustainable and effective technologies for the removal of microorganisms as well as for the mineralisation of emerging micropollutants. Within the solar based procedures, photo-Fenton showed the best performance in microbial inactivation during the experiments. However, it is necessary to further investigate this AOP to overcome some of its actual limitations.
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IWESS, an integrated water, energy and sanitation solution : A holistic approach to reach sustainability trough organic waste management for the Lake Victoria Basin, KenyaMartinsson, Erik, Martinsson, Emil, Säf, Sören January 2008 (has links)
The process of allocating necessary resources like clean water, fuel/energy and food have resulted in an unsustainable use of natural resources causing problems with Soil erosion, soil fertility, desertification, deforestation, eutrophication and global warming. The purpose of this study was to gain information on the functional design of a waste management system enabling the organic components of domestic waste to be processed as useful resources while at the same time allow them to be re-circulated. The main part of this study was carried out at the Kendu SDA Hospital in the Rachyonyo district in western Kenya. For the case of this study two main objectives where chosen. The first was to develop a principal technological solution using three classed “appropriate technologies” found suitable for the purpose namely biogas, ecological water treatment systems and slow sand filtration. The second was to further analyse each included technology to further develop their potential to fit the concept. Results from the pilot facilities where then to be retrieved from the actual component selection and construction process itself, with performance analysis left for future studies. The main purpose of the biogas system study has been to evaluate the original ideas of overall concept, details, materials and construction methods. The 1 m3 biogas system has improved significantly during the development process and is today not far from an implementation, i.e. construction on a slightly larger scale. The biogas system developed during the project has proven to have potential for digestion of both latrine and kitchen waste. Using the two as fuel for the process does not only remove a problem – it grants several benefits. The ecological waste water treatment system main objective was to design and construct a pilot SSF-wetland. Results show that the construction process for smaller scaled SSF systems is simple and does not require trained personnel or specialized equipment and that significant cost reduction can be made by using locally available materials. The slow sand filtration sub system concept is called PT SCX and though still in the stage of development proved to have great potential concerning both efficiency and sustainability. The PT SCX comprises the advantages of slow sand filtration with further development of individual system solutions. It was adapted to enable both integration to the IWESS solution and stand alone installations purifying even highly turbid surface water sources to drinking water quality. The result from the study confirms the suitability of the three included technologies, ecological waste water treatment, biogas and slow sand filtration to work in an integrated system called IWESS- Integrated Water Energy and Sanitation Solution. The combined subsystems can together with source separated sewage offer full resource recovery enabling recirculation of both nutrients and water. In addition the system can be designed as a net producer of renewable and emission free energy.
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IWESS, an integrated water, energy and sanitation solution : A holistic approach to reach sustainability trough organic waste management for the Lake Victoria Basin, KenyaMartinsson, Erik, Martinsson, Emil, Säf, Sören January 2008 (has links)
<p>The process of allocating necessary resources like clean water, fuel/energy and food have resulted in an unsustainable use of natural resources causing problems with Soil erosion, soil fertility, desertification, deforestation, eutrophication and global warming. The purpose of this study was to gain information on the functional design of a waste management system enabling the organic components of domestic waste to be processed as useful resources while at the same time allow them to be re-circulated. The main part of this study was carried out at the Kendu SDA Hospital in the Rachyonyo district in western Kenya. For the case of this study two main objectives where chosen. The first was to develop a principal technological solution using three classed “appropriate technologies” found suitable for the purpose namely biogas, ecological water treatment systems and slow sand filtration. The second was to further analyse each included technology to further develop their potential to fit the concept. Results from the pilot facilities where then to be retrieved from the actual component selection and construction process itself, with performance analysis left for future studies.</p><p>The main purpose of the biogas system study has been to evaluate the original ideas of overall concept, details, materials and construction methods. The 1 m3 biogas system has improved significantly during the development process and is today not far from an implementation, i.e. construction on a slightly larger scale. The biogas system developed during the project has proven to have potential for digestion of both latrine and kitchen waste. Using the two as fuel for the process does not only remove a problem – it grants several benefits.</p><p>The ecological waste water treatment system main objective was to design and construct a pilot SSF-wetland. Results show that the construction process for smaller scaled SSF systems is simple and does not require trained personnel or specialized equipment and that significant cost reduction can be made by using locally available materials.</p><p>The slow sand filtration sub system concept is called PT SCX and though still in the stage of development proved to have great potential concerning both efficiency and sustainability. The PT SCX comprises the advantages of slow sand filtration with further development of individual system solutions. It was adapted to enable both integration to the IWESS solution and stand alone installations purifying even highly turbid surface water sources to drinking water quality.</p><p>The result from the study confirms the suitability of the three included technologies, ecological waste water treatment, biogas and slow sand filtration to work in an integrated system called IWESS- Integrated Water Energy and Sanitation Solution. The combined subsystems can together with source separated sewage offer full resource recovery enabling recirculation of both nutrients and water. In addition the system can be designed as a net producer of renewable and emission free energy.</p>
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Heavy Metals & Wastewater ReuseHiggins, T. E. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Water shortages in the Western United States have intensified the search for new sources. Wastewater reuse is being increasingly called upon to augment existing supplies. One potential impediment to the continued expansion of wastewater reuse efforts is the accumulation of toxic heavy metals and other salts in the recycled water. Conventional and advanced wastewater treatment effect the removal of a portion of the heavy metals added during use. Removal is by chemical precipitation and adsorption and disposed of with the sludges. Potential uses of treated wastewater effluents include irrigation and groundwater recharge. Care must be taken to prevent contamination of groundwater, especially since existing wells have been reported to have concentrations of heavy metals in excess of drinking water standards. Percolation of wastewaters through soils (especially fine soils) results in a reduction in heavy metal concentrations. It is postulated that removal of these metals is by a combination of chemical precipitation with filtration of the precipitates, and adsorption on soil particles (thus the effectiveness of fine soils). Long term saturation of the soils with heavy metals may result in a "breakthrough" contamination of the groundwater. A predictive model of heavy metal-wastewater-soil interactions is proposed to aid in the design and regulation of wastewater reuse systems to eliminate or minimize this problem.
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Wastewater Effluent - An Element of Total Water Resource PlanningGoff, J. D. 15 April 1978 (has links)
From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Wastewater reuse options for the Phoenix area include: agricultural irrigation, fish and wildlife enhancement, ground water recharge, industrial processing and coiling water, recreation, cooling water for power generation stations, and exchanging effluent for additional water supplies. Consideration is given to effluent reuse potential as a commodity to exchange for water suitable for domestic water supply. This exchange would result in yet additional reuses of the water as title to the effluent could be assured by contracts and agreements.
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Resource Information Applied to Water Sources and Discharges at Existing and Potential Power Plant Sites in Arizona and the Southwest: Project Completion ReportDeCook, K. J., Fazzolare, R. A. January 1977 (has links)
Project Completion Report, OWRT Project No. A-043-ARIZ / Agreement No. 14-31-0001-4003 / Project Dates: July 1973 - June 1974 / Acknowledgment: The work upon which this report is based was supported in large part by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1964. / A growing demand for energy production in Arizona has increased the need for assembling and analyzing water resource information relative to energy production, especially electrical power generation. Unit water requirements for cooling of electrical plants, combined with projections of future electrical power demands in Arizona, provide a perspective on future quantities of water needed for cooling.
Probabilistic estimates of storage reserves in Arizona groundwater basins indicate that some prospective plant sites can be supplied from groundwater for the 30 -year life of the plant, while others cannot. An estimate of comparative cost for supplying groundwater versus municipal wastewater for cooling electrical plants at selected sites in Arizona showed that use of wastewater would result in considerable savings over use of groundwater, at all sites considered.
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Mecanismos para promoção do reúso de água nas indústrias das bacias do Alto Iguaçu e afluentes do Alto Ribeira (PR) / Mechanisms to promote water reuse in the industries of the Alto Iguaçu e Afluentes do Alto Ribeira Basins (Pr)Ratier, Cristiane 31 March 2017 (has links)
CAPES / A água é essencial para a vida no planeta e é necessária para diversas atividades humanas. Fatores como o crescimento demográfico, a expansão industrial e a progressiva urbanização, causaram o pronunciado aumento da demanda global de água, em concorrência com a redução da disponibilidade deste recurso natural. Assim, mesmo que haja volume de precipitações significativo, há risco de escassez hídrica. Desta equação resulta a necessidade premente de incentivar ações voltadas à economia e ao uso racional dos recursos hídricos. Como uma das práticas da gestão dos recursos hídricos, a adoção do reúso de água na indústria pode contribuir para a economia do insumo e a redução da poluição. O estudo parte da premissa de que a bonificação estabelecida pelo Comitê do Alto Iguaçu e Afluentes do Alto Ribeira (COALIAR), na Resolução nº 05/2013, não tem efetividade para incentivar o reúso de água. O COALIAR abrange parte da Região Metropolitana de Curitiba e municípios contíguos, no estado do Paraná. O objetivo da pesquisa é estudar os mecanismos de incentivo ao reúso de água vigentes na região do COALIAR. Como metodologia, foi utilizada a revisão bibliográfica, a pesquisa documental e a pesquisa de campo, por meio de entrevistas. Foram feitas entrevistas com atores envolvidos com recursos hídricos na região do COALIAR. A pesquisa classifica-se como descritiva e exploratória e para o tratamento dos dados foi adotada a abordagem qualitativa. Como conclusão, inferiu-se que para fomentar a prática de reúso de água são recomendáveis as normas premiais, em detrimento das normas punitivas. Os incentivos ao reúso de água podem ser estabelecidos por meio de descontos significativos, incidentes sobre valores cobrados pelo uso dos recursos hídricos, bem como por descontos e isenções fiscais. Considera-se, também, que o Poder Público deve divulgar amplamente os dados sobre os riscos de escassez hídrica e sobre os comportamentos que podem contribuir para a preservação da água. / Water is essential for life on the planet and it is necessary for various human activities. Factors such as population growth, industrial expansion and progressive urbanization have led to a pronounced increase in global water demand, in competition with reduced availability of this natural resource. Thus, even if there is significant precipitation volume, the risk of water scarcity is not excluded. From this equation results the urgent need to encourage actions aimed at the economy and the rational use of water resources. As one of the practices of water resources management, the adoption of water reuse in industry can contribute to the economy of the input and the reduction of pollution. The study starts from the premise that the subsidy established by the Comitê do Alto Iguaçu e Afluentes do Alto Ribeira (COALIAR), in Resolution number 05/2013, has no effect to encourage the reuse of water. The COALIAR covers part of the Metropolitan Region of Curitiba and contiguous counties contíguos, in the state of ParanaThe objective of the research is to study the water reuse incentive mechanisms in the region of the COALIAR. As a methodology, bibliographic review, documentary research and field research were used through interviews. Interviews were conducted with actors involved with water resources in the region of the COALIAR. The research is classified as descriptive and exploratory and for the treatment of the data, the qualitative approach was adopted. As a conclusion, it was inferred that to promote the practice of water reuse, it is recommended that the norms be awarded, to the detriment of punitive norms. Incentives for water reuse can be established through significant discounts, levied on amounts charged for the use of water resources, as well as discounts and tax exemptions. It is also considered that the Public Authorities should widely disseminate data on the risks of water scarcity and on the behaviors that may contribute to the preservation of water.
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Efeito da irrigação com efluente de esgoto tratado em propriedades químicas de um latossolo cultivado com cana-de-açúcar / Effects of treated sewage effluent irrigation on chemical properties of an Oxisol cultivated with sugarcaneRafael Marques Pereira Leal 01 June 2007 (has links)
Já há muito tempo, a irrigação de cultivos agrícolas é praticada e considerada uma alternativa interessante e útil à disposição dos efluentes gerados pelas estações de tratamento de esgoto doméstico. Como qualquer outro resíduo, o uso agrícola implica em algumas vantagens, tais como o fornecimento contínuo de umidade e de determinados nutrientes, mas também desvantagens, ocasionando a adição de sais e de possíveis patógenos e contaminantes orgânicos. Apesar da utilização de efluente de esgoto tratado ser parte integrante da gestão hídrica em muitos países, até o presente momento não se conhece nenhum outro estudo onde se utilizou e avaliou os efeitos do mesmo na irrigação da cultura da cana-de-açúcar em condições tropicais. Para este fim, amostras de solo foram coletadas e analisadas em 3 diferentes épocas. A irrigação se estendeu por aproximadamente 16 meses. O arranjo experimental foi o de blocos com parcelas subdivididas no tempo, com 5 tratamentos e 4 repetições. Os tratamentos empregados foram: (i) Controle sem aplicação de nitrogênio (N) mineral e sem irrigação; (ii) T100 a T200, 50% da dose de N recomendada via fertilização mineral e irrigação com, respectivamente, 100, 125, 150 e 200% da demanda hídrica da cultura. A produtividade foi, por ocasião do primeiro corte, positivamente influenciada pela irrigação com efluente secundário de esgoto tratado (ESET). Alterações na nutrição da cultura da cana foram pouco evidentes (teores foliares, colmo e caldo). O ESET ocasionou ligeira amenização tanto da acidez ativa (pH) quanto potencial (H+Al) Os efeitos mais pronunciados da irrigação ocorreram para os parâmetros indicadores da sodicidade/salinidade do solo, com incrementos significativos nas concentrações de sódio (Na) trocável, Na solúvel, percentual de sódio trocável (PST) e condutividade elétrica da solução do solo (CE). Estes aumentos, por sua vez, estão relacionados aos elevados teores de Na do efluente em associação com as baixas concentrações de cálcio (Ca) e magnésio (Mg), relação expressa pelos valores de razão de adsorção de sódio (RAS) do efluente. Alterações nas concentrações dos demais cátions também ocorreram, entretanto, foram menos características. As perspectivas quanto à utilização do ESET na irrigação da cana-de-açúcar são bastante promissoras, haja vista a crescente importância da cultura e a predominância do cultivo em condições de sequeiro. Entretanto, a manutenção da produtividade da cultura em patamares elevados implicará, necessariamente, a adoção de práticas específicas de manejo a fim de superar as limitações impostas pelos incrementos dos indicadores de salinidade e sodicidade do sistema solo-planta. / Since long ago agricultural irrigation has been practiced and considered as an interesting and beneficial alternative to the disposal of domestic sewage effluent. As all other residues, agricultural use implies both advantages, supplying crops continuously with water and some needed nutrients, and also disadvantages, through addition of salts and possible pathogens and organic contaminants. Although domestic sewage effluent is part of an integrated water management on many countries, none similar research is known involving sugarcane irrigation in tropical conditions. Three soil sampling campaigns were conducted. Soil samples were analyzed for quantifying acidity and exchangeable cations. Irrigation was applied for approximately 16 months. The experimental design was composed of a complete block, with five treatments and four replicates. Applied treatments where: (i) Control-no irrigation and no mineral-N applied; (ii)T100-T200, addition of 50% of the recommended mineral-N fertilization and irrigation with 100%, 125%, 150% and 200% of the crop water demand, respectively. Plant yield was positively affected by secondary-treated sewage effluent (STSE) irrigation. A small amelioration of the actual and potential soil acidity was observed for the highest dose of irrigation. The dominant effect of irrigation corresponded to increased concentrations of salinity-sodicity indicators, such as exchangeable sodium (Na), soluble Na, sodium saturation (ESP) and electrical conductivity of soil solution (EC). These increments are related to high Na concentrations for the applied effluent together with low calcium (Ca) and magnesium (Mg), relation expressed and defined by sodium adsorption ratio (SAR). Changes for other exchangeable cations also occurred, although not as clear and defined as for Na. Perspectives for STSE irrigation for sugarcane are promising, considering the growing importance of sugarcane crop and the very low cultivated area that is actually irrigated in the São Paulo State. However, the maintenance of crop productivity at high levels will necessarily imply the adoption of specific management practices suitable for ameliorating the limitations imposed by increasing salinity-sodicity parameters of the soil-plant system.
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