THE government's environment watchdog is planning a crackdown on the illegal burning of human sewage at Scotland's most polluting industrial plant.

In the next few weeks, the Scottish Environment Protection Agency (Sepa) will issue a legal notice forcing Scottish Power to stop incinerating pellets of sewage sludge at the Longannet power station near Kincardine on the Firth of Forth.

The pellets have been co-fired along with coal at the station, in breach of the law, since December 28 of last year. This was the deadline set after a high court battle in 2004 involving Scottish Power, Sepa and the Scottish Executive.

Half of all Scotland's sewage sludge, amounting to over 50,000 tonnes a year, is burnt at Longannet. The plant has long topped the nation's pollution league, belching out tens of thousands of tonnes of sulphur and nitrogen oxides, as well as toxins such as mercury and lead.

The sludge is supplied by Scottish Water and turned into dried pellets at Scottish Power's Daldowie plant in Glasgow, which also has a poor pollution record. Other sludge is spread onto land.

The court of session in Edinburgh ruled in 2004 that burning the pellets at Longannet was covered by the European Waste Incineration Directive, which imposes strict limits on emissions. Longannet cannot meet these limits without investing hundreds of millions of pounds in new technology, so the court ordered that its sludge-burning should cease by December 28, 2005. Scottish Power, however, has carried on the practice for the past two months, arguing that it is the best option currently available.

Now Sepa is taking legal action to ensure that Scottish Power submits proposals for ending the burning "as soon as possible". Sepa's southeast regional manager Rob Ebbins told the Sunday Herald:

"In accordance with its enforcement policy, Sepa is taking enforcement action against Scottish Power in respect of its breach of its authorisation at Longannet."

The move has been welcomed by environmentalists. "It is vital that flagship companies such as Scottish Power cannot get away with being above the law, " said Stuart Hay, head of research at Friends of the Earth Scotland.

Scottish Power defended its policy, arguing that an independent investigation had shown that burning sewage pellets with coal was "the best practical environmental option for the immediate future". In the longer term, the company said it was planning to build a new biomass facility in the central belt to burn the sewage.

"The new plant will provide a longterm, secure and sustainable solution for the disposal of sewage while supplying green energy and helping meet renewable targets, " said a spokesman for Scottish Power.

But the biomass plant, which could cost up to [GBP]50 million and generate up to 50 megawatts of electricity, will not be up and running until 2009 at the earliest, meaning that illegal sludge burning at Longannet could continue for at least the next three years.

That prospect has been seized upon by the Scottish Green Party as evidence of the Scottish Executive's "complacency" in dealing with companies flouting environmental law. "Ministers knew months ago that this court ruling was going to kick in last December and they opted to bury their heads in the sand, " said Green MSP Chris Ballance.

"There now needs to be urgent consideration of all the options based on the latest research, and a coherent strategy put in place. The reality is that sewage has to be treated and managed, and the sooner ministers get on with doing that, the better."

The Executive responded by pointing out that Scottish Power was working closely with Sepa to comply with the regulations as soon as reasonably practicable. "We expect Sepa to work with Scottish Power to identify long-term sustainable solutions, " said an Executive spokesman.

This week the Scottish parliament's Environment and Rural Development Committee is launching an investigation into the potential for burning biomass to cut pollution and boost rural economies.

"This is a chance for the committee to consider how policy and incentives can be developed to maximise the development of biomass in Scotland, " said the committee's convenor, Sarah Boyack MSP.

NEED TO KNOW

THE FACTS Scottish Power is breaching a court order by burning sewage pellets at Longannet power station on the Firth of Forth, and is being taken to task by the Scottish Environment Protection Agency.

BACKGROUND In 2002 Longannet emitted 67,100 tonnes of sulphur oxides, which cause acid rain, 23,500 tonnes of nitrogen oxides, which cause breathing difficulties, as well as 13 other hazardous pollutants, including carbon, mercury, lead and dioxins.