Demonstration of Wastewater Treatment for Reduction of coastal water contamination from Manora Island Karachi

Objectives

1. Sewage pollution from Manora Island in coastal waters of Karachi reduced through demonstration of a Reed Bed system

2.The lessons learnt under the project used as an advocacy tool to influence policies and practices to control land-based pollution

Background

Manora is a small peninsula located just south of the Port of Karachi and is connected to the mainland by a 12 km long cause way. Manora and neighboring islands form a protective barrier between Karachi harbour to the north and the Arabian Sea to the south. The western bay of the harbour contains mangrove forests. The area contains shallow tidal lagoons, intertidal mudflats, saltpans and about 400 ha of mangrove swamps. Manora is also a prime recreational site for citizens of Karachi and a large number of visitors (estimated as 150,000) come to the area annually.

The proposed project is aimed to reduce a water contamination caused by dumping the untreated wastewater directly in sea, which create the seawater contamination. The project will employ use of Reed Bed System demonstrate biological wastewater treatment model (constructed wetland system) for reduction of sewage pollution from the Manora Island in coastal waters of Karachi and demonstrate this technology to influence policies and practices to control land-based pollution sources.

Constructed Wetland is a natural, low-cost, biological wastewater treatment technology designed to imitate the processes found in natural wetland ecosystems. The system involves a series of filter beds planted with reed plants to treat wastewater passing through the root zone. The primary treatment of effluent is done through screening and grit chambers to filter the large solids/floatables from the wastewater. Thereafter, the water is passed through a series of baffled settlement tanks to remove suspended particles before it passes through the filter beds planted with reed plants. The strata of gravel pebbles and roots of reed plants support in aeration of wastewater and predation by micro-organisms to improve quality of water. Inlet and outlet pipes are positioned below the gravel surface. The system is cost effective, as it is less energy intensive and uses a natural gradient for flow of wastewater through the various filter beds.

Target beneficiaries

The direct project beneficiaries include naval cadets and local residents of Manora Island who will benefit from reduction of marine pollution and greening of sports field for healthy activities. The demonstration effect of the project may be useful for policy advocacy with coastal stakeholders belonging the government, civil society and private sector who are concerned about marine pollution.

Outputs

Output 1:          Pre-project assessment of sewage pollution from Manora Island carried out for baseline data

Output 2:          Post-project assessment of sewage pollution from Manora Island carried out and compared with the baseline

Output 3:          One pilot Reed bed system established at Manora Island

Output 4:          Treated sewage water reused of for greening of one acre area

Output 5:          Advocacy and awareness on control of marine pollution issues conducted

Output 6:          Lessons learnt from the project documented and disseminated

Accomplishments and challenges

1. One constructed wetland system using Reed bed plants has been installed at Manora Island to treat sewage water with a capacity of reclaiming 30,000 gallons of sewage water per day.
2. A barren sports field used by naval cadets and the local residents of the naval colony for sports and recreational activities has been transformed into a green field.
3. The generated water has reduced water resource competition for the plantation and irrigation of sports field covering an area of three acres and maintaining tree plantations and greening of roadside shoulders at the Island.
4. The biological wastewater treatment concept is being replicated by PN at other locations and around 14 such models have been either constructed or are in the process of establishment by Pakistan Navy. Of these, five units are operational with a cumulative capacity of 287,000 gallons per day.
5. Project results have been documented and disseminated and the lessons shared at various levels and at national and international forums.
6. Exposure visit of media, policymakers and NCB members to the Reedbed System site organized.
7. A policy paper on status of marine pollution along the Karachi coast has been prepared for future advocacy on coastal pollution issues.

Contributions to cross-cutting themes

- Climate change:

The project will contribute to address climate change related aspect. Since the project aim is to reuse the waste for irrigation purpose a substantial quantity of fresh water already utilizing for irrigation may be saved. As Pakistan is in the red zone in accordance with the water state, therefore saving of fresh water will contribute to Climate change and environment issues at the island. n addition, greenery of the additional area through reuse of waste water will also contribute to sequestration of CO2 as pollutant from the sewage water will be removed. Mangroves in the areas will have clean water in the roots and more CO2 will absorb and subsequently more CO2 will be available for marine species. Therefore this project will reduce the climate change effects in the area.

- Gender:

Recreational parks development may be possible and all the population (male/female) would have equal opportunity of recreation. Women will be accessed to generate awareness regarding the waste contamination specially the lady teachers of different schools. Through the mobilization activities their capacities will be built as to how to minimize the contamination and recycle the water at household level.
The project will provide an opening to all the students from Universities (male/female) for participation in project actively especially during designing, sampling and construction phases.

Lessons Learned

1. The constructed wetland has successfully demonstrated a low cost biological wastewater treatment model for treating wastewater and recycling it for different purposes.
2. The project has resulted in saving an estimated 10.8 million gallons of freshwater per annum that would otherwise be used for greening purposes at the Island.
3. In monetary term reclamation of wastewater is resulting in saving handsome amount of approximately RS 6.9 M per annum that would otherwise be spent on procurement of freshwater.
4. The project has influenced PN’s interest in coastal management issues and its engagement in mangrove conservations and establishment of Marine Protected Areas in Pakistan in collaboration with other coastal stakeholders.