Upscaling and amplification of the Msingini Wastewater treatment facility model in Chake Chake town, Pemba

Project Summary:

Coastal ecosystems along the Zanzibar archipelago are of great ecological and socio-economic importance. However, they are under intense pressure from land-based activities and pollution from both municipal and industrial activities. Untreated industrial effluents from the municipalities and coastal settlements have resulted in the unwanted discharge of untreated municipal waste waters, especially raw sewage, directly to the marine environment, ultimately affecting the ecological balance as well as sustainability of coastal and marine systems that support the livelihood of over 1.3 million people living on the archipelago. To offset these impacts, the UNEP Nairobi Convention, under the key objectives of the UNEP GEF WIO-LaB Project, supported the establishment of the first ever wastewater treatment facility in the Zanzibar archipelago. This facility was built on the island of Pemba along the western edge of Chake Chake Town and fully commissioned in 2011. It has been managed since inception by a consortium of the Chake Chake Town Council (CCTC), the Department of Environment (DoE) and Zanzibar Environment Management Authority (ZEMA). The treatment facility has however had various challenges  (i) a low level outlet which can cause problems during times of high tides, storm surges and heavy rainfall as the outlet is then underwater and treated effluent is not able to discharge freely , (iI)combined storm water and sewer pipes lacking a free outfall into the sea during high water events, causing a mixture of this water to back up and spill out onto the streets and (iii) limited ability to accommodate or adjust to a climatic or tidal event and maintain or quickly resume their primary function, a quality known as the adaptive capacity. This adaptive capacity is even more essential in consideration of sea level rise, which will push the systems to even greater limits of operation.

The project seeks to utilize the existing under-performing Constructed Wetland System on Pemba Island and significantly improve its long-term management, efficiency and benefit to the surrounding community of more than 5,500 people, both in terms of capacity and productivity. The project will work to enhance the adaptive capacity of the facility by modifying the hydraulic operation of the system, installing protected outlets and introducing flow buffering/retention. The site boundaries may also be raised to prevent inundation in years to come.   Due to its location in a low-lying coastal area, its adaptive capacity to withstand the effects of sea level rise and extreme climatic events is a central part of the redesign. A list of approved laboratories for analyzing wastewater samples will also be created.   Increasing local capacity to operate and maintain the system will be emphasized to ensure long-term sustainability and the introduction of a Payment for Ecosystems Services system will help to cover these costs. Improved utilization of the wetland plants after harvesting will increase the community’s appreciation of the system and result in cost savings and/or income. These mechanisms will ensure adherence to standardized monitoring protocols, which in turn allow improved management of wastewater treatment systems throughout the archipelago. It is vital for the local partners to have an established framework to adhere to for long-term protection of the Islands’ environment.