Identificação e análise dos fatores condicionantes do desempenho dos dessalinizadores no estado do Ceará

Abstract

Water shortage in Ceará has been causing emergency actions regarding its supply to rural communities. In most parts of rural areas of Ceará, the water provisioning is accomplished in a quite precarious way, and huge parts of those communities' population do not have any system of water provisioning at all. To assist communities with few families and in regions of difficult reaching, the construction of cylindrical wells for reception of underground water comes still as one of the best-found alternative to help the rural population to live with the problem of water provisioning in the semi-arid region of Ceará. However, the existence of high levels of salt in the water of the wells comes as a serious problem that harms that provisioning. In Ceará, 80% of wells present water with excessive salinity, inadequate to human consumption and, therefore, a salt remover mechanism in these cases would be necessary. Today, the presence of those salt removers is a reality to many municipal districts of Ceará. However, we should stress that the adoption of salt removers is not simple and, the use of that machine requires regular maintenance. The main goal of this research is to evaluate the functioning of salt removers installed in municipal districts of Ceará, under the economic and social aspects. Besides, to identify, to describe and to analyse the characteristics of salt removers and, to measure the impact of the main variables that influence its functioning. For this research, primary data were used starting from the application of questionnaires in 130 communities of Ceará that possess salt removers. It was also used secondary data, sourced from Programa de Recenseamento de Fontes de Abastecimento de Água Subterrânea no Estado do Ceará (Program of Underwater Supply Sources Census of Ceará), accomplished by Companhia de Pesquisas de Recursos Minerais (Company of Mineral Resources Research) — CPRM and from Superintendência de Obras Hidráulicas (Superintendence of Hydraulic Works) -— SOHIDRA. To assist the goals of the research, the analysis was made through data tabulation and also using the model Probit, with dichotomised and dependent variable. The evaluation of the functioning of salt removers, in a general way, was considered satisfactory. Less than half the salt removers showed technical problems or were stalled. With the use of the Probit model, the identified variables that influenced the functioning salt removers were: brand of salt removers, installed capacity, level of salinity and course of the operator. Among those variables, it stands out the installed capacity and level of salinity, because the marginal effect of those variables disclosed the likelihood of the operation of salt removers. One more conclusion of the research was related to the lack of planning in the use of waste originated from of the salt removing process. Concerning this, it is recommended that, the use of the resulting waste should be addressed in the content of the project for the installation of salt removers, in order to avoid future harms to the environment.