A series of odour and water pollution incidents caused by land spreading operations has focused attention on the issue in recent years. The latest Scottish prosecution for such pollution came in November (see p 49 ).
Interest in land spreading as an alternative outlet for industrial waste has been stimulated by the landfill tax, introduced in 1996. Since 1994, the practice has also enjoyed an exemption from waste management licensing, so that contractors need only pre-notify regulators of their plans. Up to 250 tonnes of waste per hectare may be spread each year, as long as this results in "benefit to agriculture or ecological improvement".
The Scottish Office asked SEPA to undertake a strategic review of waste spreading last year. Some of its proposals echo those in a recent report for the Environment Agency (ENDS Report 281, pp 27-29 ). But SEPA has also developed some more specific regulatory proposals which the Scottish Office is now considering how to take forward. As with the proposals being developed south of the border, amendments to secondary legislation will be required.
As well as industrial waste, SEPA's report addresses other organic wastes, including agricultural waste, sewage sludge and compost. It estimates that 367,000 wet tonnes of industrial waste and 200,000 tonnes of sewage sludge are spread in Scotland each year. These figures are dwarfed by the estimated 15 million tonnes of agricultural waste applied to land.
Data on land spreading are unreliable because there is no record-keeping requirement except for sewage sludge. According to SEPA, important industrial waste streams spread on Scottish land include 76,000 tonnes per year from the food and drink industries - mainly distilleries - and 49,000 tonnes from the paper industry, as well as 26,000 tonnes of abattoir waste.
SEPA notes that spreading organic wastes can bring benefits such as nutrient addition and soil conditioning. But some waste producers regard the practice as a form of disposal rather than recycling - and in turn farmers have little understanding of the benefits which it can bring and rarely reduce applications of conventional fertiliser.
"Nutrient addition from what is in effect a free source is generally discounted," the report says. And, in the case of industrial organic wastes, farmers are generally unable to optimise application rates to meet crop requirements because there is little evidence from field trials.
"It is SEPA's experience that the application rate of [industrial organic] wastes is seldom if ever matched to the nutrient needs of the growing crop," the report says. "As a result it is suspected that nutrient leaching occurs widely."
Other environmental impacts from land spreading of industrial wastes include oxygen depletion in watercourses, and the presence of contaminants such as fungicides and bactericides used in many industries, including the paper and textiles sectors.
On odour pollution, SEPA notes that pre-treatment of wastes can reduce odour problems in some cases, as can changes to storage and application techniques.
SEPA's paper also examines sources of pathogen contamination from organic wastes - in particular slurry, manure, sewage sludge and abattoir wastes - and possible control measures. In the case of sewage sludge, the Government has recently agreed that spreading of untreated sludge should stop by 2002.
Presumably, SEPA's proposed framework would cover the spreading of agricultural wastes - but it avoids spelling this out in the paper.
In a parallel exercise, the Government is planning to consult on proposals to bring some agricultural waste under normal waste controls, in order to fulfil a long overdue EC obligation - but this has now been delayed until March 1999. It is possible, therefore, that a new regime on land spreading might include controls on agricultural wastes.
SEPA proposes that the current pre-notification regime for land spreading of industrial wastes should be abandoned, not least because some parties wrongly feel that by pre-notifying SEPA of their plans they have gained its approval. "Rather than pre-notification, it is suggested that greater benefit would be offered by the keeping of detailed records by the waste producers/contractors and landowners and auditing of these records by SEPA," it says.
Under SEPA's proposed regime - funded through a new charging scheme - any waste producer wishing to recycle organic waste to land would face a series of conditions:
Minimum standards of pre-treatment would be stipulated - presumably in statutory guidance - though this would not apply to most agricultural wastes.
Controls on land use following the application of farm wastes and industrial wastes similar to those which currently apply after spreading sewage sludge would be introduced. The aim would be to minimise risks from pathogens.
SEPA also recommends that waste producers should have access to "properly qualified advice" to take account of nutrient requirements and contaminants in the waste. And it says that contractors should be subject to a competency scheme similar to the statutory certificates of technical competence required in other waste management fields.
"Difficulties might be expected in future years due to the cumulative effects of increased disposal," SEPA says, noting that the UK is unique in the EC in allowing widespread on-farm burials. The Government is currently consulting on proposed changes to animal by-products legislation which would further restrict burial of fallen stock (see p 37 ).