Mecanismos alternativos de cobrança pelo uso dos recursos hídricos para assimilação de efluentes

• Autor(a) principal: Moreira, Amanda Rodrigues
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3674
• topic: Recursos hídricos; Mecanismo de cobrança; Equivalente populacional; Water resources; Charging mechanism; Population equivalent; CNPQ::ENGENHARIAS::ENGENHARIA SANITARIA::RECURSOS HIDRICOS

Brazil has a privileged location concerning to water availability, in spite of that, geographical and temporal variability, the endangered quality of this resource and rise of demand have led to conflicts for its use. In this context, Law no 9.433, January 8 th 1997, also known as Law on Water , introduced charging practices on water use as a quantitative and qualitative management tool. In a regional scale, the Doce river Watershed Committee (CBH- Doce) has already implemented such tool in which the collection method for effluents discharge is based solely on the organic load parameter, quantified in terms of Biochemical Oxygen Demand (BOD). The method is relatively insufficient concerning to the variety and composition of effluents, which might not be treating accurately the actual water volume that is impaired due to a variety of discharges. Therefore, the present study aimed to study and evaluate alternative mechanisms for charging water resources use for effluents assimilation, specifically seeking the introduction of new parameters, in addition to the BOD as calculation criteria; and evaluate the potential for collection taking Doce river watershed as a case study. In order to accomplish such objectives, literature review was developed for selecting parameters that characterize water quality of sewage and other effluents for predominant segment/sectors/activities of main users discharging into the watershed, which would more represent the endangered water quality to apply the proposed alternatives and through revisions of other water resources management systems, nationally and internationally. Proposals to charge for the water resources related to effluents assimilation. In order to analyze the collection potential of these new proposals in the given watershed, a collection simulation of the amount to be charged for the sanitary sector was developed. The current scenario was taken into consideration users of the years 2011/2012 in addition to the evaluation of 3 scenarios in which were simulated the effects of the adoption of different degrees of sanitary waste treatment in the washbasin. For that, launched flow data base, besides treated flow were used, which contributed for estimating current treatments in the watershed. Additionally, data regarding enterprises and users currently in charge (answered the charge in 2011 and 2012), besides literature data regarding to the characteristics of sanitary sewage and major pollutants efficiencies of typical removal of interests in sanitary sewage of system chosen. After analysis were made, it was decided that the parameters which were to be applied in the proposed alternatives would be Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), ammoniacal nitrogen (NH 3+ -N) and Total Phosphorus (P T ), besides inorganic compounds and bio recalcitrants according to typology of the enterprise. Two proposals have arisen: the Limiting Population Equivalent (LPE), which is based on the theoretical value of pollution generated by one habitant; and the Impaired Volume (IV), which is based on the dilution principle, in other words, number of cubic meters of water needed to assimilate a given pollutant load. Proceeding with the simulations, there was an increase of 64% in the value collected for the LPE proposal and an increase of almost 6 times for the IV one. In case treatment systems are implemented in the watershed, a decrease of approximately 17% in the total amount to be paid was observed in the simulations. In addition, for 100% sewage treatment simulation through a UASB reactor followed polishing ponds. In case 50% of the sewage was treated in UASB system followed by trickling filters, this reduction would be smaller, approximately 3%. In conclusion, alternative mechanisms would comprehend widely the real issue of water quality of Doce river watershed, once it also accounts other variables than BOD. Both proposals present great versatility that enables them to be applied in any watershed, being chosen most relevant parameters in relation to the water quality of the locality. In general, the Limiting Population Equivalent was considered easier to apply and more comprehensive.