Evaluation of drinking water technologies used in South-Western coastal Bangladesh a case study

Abstract

Drinking water scarcity is a silent and ancient disaster round the year, especially during the dry season (November - May) in the coastal areas of Bangladesh. The problem became severe after the cyclone Aila. Different types of drinking water options, including Open Pond Water (OPW), Hand Tubewell (HTW), Deep Tubewell (DTW), Artificial Aquifer Tubewell (AAT), Rain Water Harvesting (RWH), Artificial Rain Water Harvesting (ARWH), Piped Water Supply (PWS) and Water Treatment Plant (WTP), are already being practiced here for a solution of the problem. But there is no holistic study of these technologies in context of technical suitability, economic viability and social acceptability as a whole. The basic objectives of this study are to identify the technical suitability in terms of water quality, economic viability in terms of installation and operation and maintenance cost, and social acceptability from different social aspects of these technologies. Atulia union, Shayamnagar upazila under Satkhira district in the southwestern coastal region was selected as the study area because the problem of safe drinking water is severely acute in this area and most of the drinking water technologies are used here. To evaluate technical suitability, primary data was collected three times during March to May of 2014 by spot testing of pH, EC and DO with mobile apparatus, laboratory analysis of TSS, TDS, hardness (Ca2+ and Mg2+) and microbial contamination (TC and FC) at IWFM, BUET. An un-structured questionnaire was used to collect socioeconomic perspectives of the drinking water technologies. The weighted average method with a multifactor performance matrix is used to identify the suitable options. According to installation cost, low capital cost (< Tk. 50,000) drinking water technologies are OPW 1, RWH, ARWH, HTW and PSF; medium capital cost (Tk. 50,000 – 100,000) technologies are OPW2, OPW 3, AAT and DTW; and high capital cost (>Tk. 100,000) technologies are WTP and PWS. The water quality parameters and social aspects revealed that, high capital cost drinking water technologies, i.e. WTP, is suitable as well as first priority of the local users. WTP, a high capital cost technology, is the best choice and OPW 1, low capital cost technology, is the worst choice of the users. RWH is popular for easy to use, individual ownership and good taste of water. However, microbial contamination and year round unavailability are the major constraints. PWS is users‟ another preferred choice, however, poor maintenance, misuse of water and microbial contamination are basic problems for its long term use. DTW is functioning well in a specific layer (200m-350m). AAT is a good choice in social issues for easy pumping facilities rather than PSF, however, water quality is unsatisfactory due to water clogging problem inside its filter. Water quality of PSF remains fine initially, however, it deteriorates quickly due to poor maintenance and PSF becomes a less acceptable technology among the consumers. Communal OPW 2, OPW 3 and private OPW 1 drinking water sources are not suitable for consumption due to pathogenic contamination, however, people use it traditionally. HTW is suitable for household activities, however, unsuitable for drinking purpose. Competitively low capital cost technologies can draw short term solutions. However, without continuous operational and maintenance fee collection, these low cost technologies are unable to provide the safe drinking water for a long period. Assured, accessible and sustainable safe water market already exists through a system of payment by the users. The WTP and DTW with piped water system can meet both the demand of the local communities and financial viability in the newly formed water market. These facilities demand capital investment and long term plan from the government, non-government and donor agencies.