Foreword

Sewage generated from the domestic sources is a major source of water pollution. For preventing the pollution of rivers and other water bodies, treatment of sewage and its proper disposal is a pre-requisite. Over the years, conventional treatment systems have been in practice throughout the world for the treatment of sewage. These systems are cost and energy intensive and require trained manpower for operation and maintenance. Hence, it is necessary to look for simple and low cost wastewater treatment technologies and utilization of nutrients in wastewater.

n a bid to develop and demonstrate the low cost treatment technology, the Central Pollution Control Board sponsored a project on Duckweed based wastewater treatment to M/s Sulabh International. The project was conducted for three years in Delhi and in Halisahar, West Bengal.

The findings of the project indicate that the duckweed based wastewater treatment system can be used for the small towns or in rural/semi rural area, where the land is available and harvested duckweed can be used for different economic uses including pisciculture. Based on the project, guidelines have prepared by an Expert Group headed by Dr. G.D. Agrawal.

We hope, the guidelines will be useful for the civic authorities and others concerned with wastewater management.