28 April 1995

Dump ban prompts moves to clean up sewage sludge act

SEWAGE sludges image is being revamped, in the east at least, thanks to an Anglian Water/ ADAS link up.

The move precedes the impending ban on dumping at sea in 1998. In addition to the five-year agreement, through which sludge users get free access to ADASs Ferti-plan service and agronomy advice, Anglian has "significantly" re-organised its Award field service, according to waste disposal manager Peter Garnett.

Nineteen recycling specialists have been appointed in its eight areas from Lincs to Essex. And to reflect increasing diversity in sludge types the company now refers to them as "biosolids".

An ADAS survey of 3600 farmers, both users and non-users, suggests about three-quarters appreciate biosolids fertilising and soil conditioning benefits. But it highlights several areas of concern the company is striving to address.

One of the main worries centres on application equipment and spreading rates. Without a guaranteed dose it can be tricky to adjust fertilisers to take account of sludge nutrients. Competitive tendering for spreading may have been responsible for past problems, Mr Garnett concedes.

In future the aim is to give contractors a "fair price" to allow them to invest in modern equipment, for example incorporating flow meters. This should permit profitable operation to "achievable standards".

Professional contractors are seen as vital to encourage the increased biosolid use which will be needed as coastal discharge plants are closed. Howard Everson of Thetford-based Clear Waste believes "septic Sids" are a dying breed.

Inconsistency of sludges, and occasionally supply, are other complaints unearthed by the survey. Mess and odour are "clearly a concern", and cake sludge is sometimes too wet and heavy.

"Litter" ploughed to the surface after sludge injection is "a big issue". The company is "investing heavily" in 6mm screens at treatment works to eliminate the problem, claims Mr Garnett.

Most of Anglians sludges, 83% of which already go on to agricultural land, come from non-industrial sources with heavy metal levels said to be declining.

ADAS can help clarify sludge reports, which some growers find hard to understand, he adds. It will also be involved in trials on Anglians newly acquired demonstration farm in Lincs. &#42

Improved equipment can help growers use recycled sewage sludge waste cost-effectively and in an environmentally acceptable manner.