This report describes the investigation of a mission by the FAO/UNDP South China Sea Programme for feasible solutions to the environmental pollution problems arising from 3 pig estates in the Island of Penang at Pantai Acheh, Gertak Sanggul and Batu Maung. On the basis and recommendations of previous missions more detailed proposals for possible immediate mitigation and also solution on long term basis are made.
The basic problem is that animal wastes are being washed out from the pig farms, and that the effluents from the estates have an extremely high content of nutrients and settable solids, which have caused clogging of natural and man-made drainage systems and depletion of oxygen in these rivers, canals and even part of a bay.
As solutions to this problem the use of the animal waste in aquaculture is recommended. The biological principles and ways of application of the waste utilization are described. Besides recommendations for Pantai Acheh and Gertak Sanggul, the proposals for construction of fish-ponds focus on the biggest pig estate Batu Maung as the environmental implications are most pronounced. Here, the implementation of the integrated pig farm-aqua-culture, with possible further biogas production, will serve best as a pilot project for the mitigation of the pollution problems in other pig estates.
Four solution alternatives are described. All alternatives are based on the principle of separating the solid and liquid phase of the wastes and on the exclusive application of the liquid phase of the wastes in the aquaculture ponds, a practice occasionally but not yet commonly used. This necessitates the construction of one or two settlement tanks as a basic requirement for all four alternatives:
as immediate measure the present canal system is cleaned, diked and used as fish-ponds yielding ca. 3.8 ha of pond surface, serving for utilization of waste from 3 500–4 000 pigs.
part of the mangrove belt is reclaimed and converted to fish-ponds, yielding ca. 12 ha pond surface, serving for utilization of waste from ca. 12 000 pigs.
the present canal system plus part of the mangrove belt (less than in alternative 2) is converted to fish-ponds with the same surface as in alternative 2.
phase 1) immediately uses the cleaned and diked canal system as ponds for partial use of the waste,
phase 2) then uses ca. 12 ha already allocated land along the airport as ponds, leaving the previously constructed ponds as water reservoirs; or additional fish-ponds.
The application system for the liquid waste is described, and rough cost estimates are made for all alternatives. Problems of fresh water supply, alternative brackish water cultures, desired fish species and stocking rates are discussed. Some economic considerations and recommendation for financing the pilot project are made.
