Environmental impact assessment for the proposed project to upgrade the sewerage system Manadhoo Noonu Atoll, Maldives

Abstract

This report discusses the findings of an environmental impact study under the proposed sewerage system upgrading project at N. Manadhoo. The project is proposed by Fennaka Corporation limited. The project entails upgrading the sewerage system to improve the existing sewerage treatment plant. The proposed upgrading involves incorporation of sea outfall with pumping station as emergency outfall and modification or replacement of two fiber tanks in the sewage treatment plant. The project has been proposed to repair the exiting treatment plant as at the moment, due to damages to the STP raw wastewater is discharge into the lagoon directly. Upon recommendation from the consultants and in accordance with the existing guidelines, an emergency bypass has been included in the design with one additional pumping station. The emergency outfall will pump wastewater beyond the house-reef at about 15m depth. A number of alternatives to the proposed project components have been identified in this document. Of these, the recommended alternative involves changing the proposed outfall location slightly to east which will reduce the length of outfall pipe and hence lower the implementation cost considerably. Other alternatives include considering different emergency outfall environments such as ground and lagoon. Environmental impacts were assessed for both the construction and operational phase of the project. Most of the environmental impacts identified for the proposed development were positive; these include reduced pollution of the marine environment and increased aesthetic value of the beach. The main negative environmental impacts of the project would be temporary loss of groundwater quality during the construction phase due to dewatering and small amount of sedimentation around house-reef induced from installing the emergency outfall. The latter could be regarded as insignificant due to its small magnitude and spatial distribution. The proponent is willing to undertake monitoring during and after the construction phase in addition to undertaking the mitigation measures proposed by the consultants. The main mitigation measures for this project during the construction phase are similar to other construction projects such as dust control plans, working during low- tide as much as possible and rigorous supervision. As for the operational phase, implementation of backup systems and trained maintenance staff to service the Sewage Treatment Plant (STP) and regular check-ups were suggested in addition to monitoring seawater quality around the outfall location. In conclusion, it appears justified from a technical, administrative and to some extent environmental point of view, to carry out the proposed project to upgrade and repair the existing sewerage system. However, there are alternatives that may be more suitable and shall be considered with caution and after understanding the costs and discussions with relevant government authorities.