CHENNAI FEB. 2. Waste management experts presented a gamut of scientific solutions during a session on `Technologies for resourcing waste' here yesterday, while activists attempted to run down some of them, especially the Energy Development Limited waste-to-energy project announced by the Chief Minister, Jayalalithaa, in the Assembly on Friday.

Pressed to implement the Municipal Solid Waste Management and Handling Rules, 2000, Tamil Nadu's search for solutions is throwing up new technologies, some of which have upset activists and urban managers. They are concerned especially with the potential toxicity of waste-to-energy projects like the EDL.

``There are apprehensions over technologies for solid waste management. We should try to address them,'' the managing trustee of Citizen's Alliance for Sustainable Living, M. G. Devasahayam, said, setting the agenda for the session, jointly organised by the Institution of Engineers, the Indian Water Works Association, the Exnora International and the SUSTAIN.

The EDL Solid Waste and Energy Recycling Facility using gasification pyrolysis has been receiving flak from activists and the Tamil Nadu Pollution Control Board even refused clearance stating it was unsafe.

Using the session as a platform to present EDL's case, its managing director, Sunand Sharma, said the company met TNPCB officials recently to explain the process. The Rs.180-crore project has now been cleared and the plant will be set up near the Perungudi dumping yard.

``It will comply with the MSW rules,'' Mr.Sunand said. Most of the recyclable and reusable wastes are removed by rag-pickers at the disposal stage itself or at the dumping yards, leaving behind only real waste. This would undergo a pyrolysis process in an upgraded gasifier plant. ``It will take place in an oxygen-free environment. It is not combustion.''

Activists refused to accept his account. ``Pyrolysis is a burn technology,'' countered T. K. Ramkumar, principal advisor, Exnora International Foundation, an NGO specialising in waste management through community participation. He raised doubts over the SWERF process, which faced some hitches recently at the EDL parent plant in Wollongong, Australia.

The unit cost of power generated by the plant would be Rs.3.87 for this year and is likely to increase later. However, it will take at least two years for the plant to be set up.

In a presentation on `Sustainable Landfills', assistant professor, Environmental Engineering, Anna University, Kurian Joseph, advanced the need for controlled, engineered dumps to quicken the biodegradation of wastes and as counter-solutions to environmental threats posed by open landfills.

The executive president, LVK Enviro Consultants, N. K. Kuttiappan, giving a presentation on `Decentralised waste water recycling', said at least 40 per cent water can be recycled through miniaturised hydrological cycles. Water harvesting through sewage reclamation can be done daily unlike rainwater harvesting''.

Another presenter, a technical consultant, G. Jayaraman, proposed treating processed waste in cement plants for use in kilns. ``The process will absorb any toxic material and for substances like sulphur and alkalis, bypass systems are available.''