Archives > Bio-management of Sullage Ponds

2.1. Duckweed Technology

The ponds in the villages of Punjab are facing pollution problems. The Council studied the problem through a survey of some representative villages of Punjab. As the available technologies for the treatment of waste water involve high capital as well as operational and maintenance costs and also offer no economic returns, hence, an urgent need was felt for alternate technological options. The Council suggested duckweed technology in conjunction with pisciculture as remedy to the pollution problem of village ponds as a sustainable solution.

Duckweed is free floating and fast growing aquatic weed, which improves the quality of the sullage for safe disposal. The existing pond is divided into two parts, and the sullage is received in one part of the pond. For successful cultivation of duckweed and treatment of sullage, the duckweed should cover entire water surface in the pond and therefore, the pond is divided into grids using floating bamboos as otherwise the duckweed tends to drift towards one side with wind current and decay. The duckweed absorbs the organic content of waste water and brings down the biological oxygen demand of waste water from a level as high as 150 mg/lt to less than 30 mg/lt. The sullage after treatment through duckweed technology is utilized for pisciculture and the duckweed grown on sullage is utilized as complete feed for the fish. Duckweed grows very fast and doubles within 48 hours. It is harvested and fed to the fish through fish feeding stations. A combination of duckweed and fishponds of one hectare each could earn revenue of Rs. 0.75 lakh approx. through sale of fish.

The Council has demonstrated duckweed cum pisciculture technology for the management of sullage in three villages namely Sanghol and Chanarthal Kalan in district Fatehgarh Sahib and Sandhua in District Ropar. The operation and maintenance of these projects in the above said villages has been entrusted to village panchayat. The duckweed technology therefore, generates self-employment and help the village panchayats to generate revenue.

Contact Person: Dr.Rajesh Grover, rgrover@pscst.com