Environmental impact assessment : GDH. Thinadhoo wastewater collection, treatment & disposal system

Abstract

This Environmental Impact Assessment describes the potential impacts and benefits expected from the development and operation of new sewage systems designed for the Island of GDh Thinadhoo. The project proponent is the Ministry of Housing and Environment (MHE), with the Environmental Protection Agency (EPA) acting as the oversight authority for development projects being undertaken in the country. The provision of safe water supply and sanitation, particularly in the wake of the 2004 tsunami, has become an urgent task for the Maldives Government. The MHE developed an action plan for the implementation of water supply and sewerage projects in tsunami affected islands and focus islands for regional development. A large range of reconstruction projects are now underway to upgrade or create new sewerage systems on as many islands as possible using the most appropriate technologies suited to the local conditions that will result in environmental improvement. This includes projects for the replacement of damaged septic tanks, and the installation of new septic tanks, sewer pipe networks and treatment systems. The project specifically seeks to improve sanitation conditions for residents of the four islands (including expected future expansion of populations), condition of the groundwater and other environmental factors responsible for supporting the island ecosystems and on which humans depend. The project was funded by the Agence Française de Développement (AFD) and the Maldives Government. This EIA complies with the Environmental Impact Assessment Regulations, 2007. The environmental conditions prevailing on the small coral atoll islands of Maldives differ substantially from those found in larger continental countries. To ensure that the assessment was appropriate and accurately reflected the likely types and magnitude of impacts and the regulatory conditions in the country the EIA was based on a review of the scientific literature and relevant national guidelines. The two most important national guidelines used were the Design Criteria for Sewerage Systems and the National Waste Water Quality Guidelines (NWWQG). The main methods used for conducting the study included (i) Review of relevant past studies and literature; (ii) Review of design criteria and guidelines; (iii) Detailed assessments of existing conditions on each island; (iv) Investigations of the sites to be used by the project; and (v) Public consultations.

The project was developed by MHE as a design and construct contract with a design horizon of 30 years for the sewerage network and 15 years for associated hardware and the Sewerage Treatment Plant. Bio-solids produced by the Sewerage Treatment Plant will be dewatered in drying beds and mixed with sanitary landfill or reused for agricultural compost. Sewage will be treated to the level required to meet NWWQG guidelines before disposal at sea.