Sewage discharges improve, but industry lags behind

One-third of industrial discharges failed to comply with their consent conditions in 1990-2, according to a report by the National Rivers Authority (NRA).1 The water industry's compliance record is considerably better - but not as good as it seems at first sight.

The report is a guide to the operation of the discharge consent system in England and Wales, and provides a helpful outline of impending changes in the NRA's consenting and monitoring policies.

The report also provides the first compliance data since the NRA's establishment in 1989. These cover the period 1990-2, and the NRA intends to publish annual figures from now on.

The figures are summarised in the table below. For sewage works, they show a generally consistent regional improvement in compliance over the three years, with the overall rate advancing from 90% to 95%. This would be even better were it not for South West Water's poor performance. The report attributes this "at least in part" to relatively stringent consent conditions set before the company was privatised, and the high loads imposed on its sewage works during the tourist season.

Industrial dischargers performed poorly by comparison, with a compliance rate of only about two-thirds in each of the three years. The overall rate appears, in fact, to have been poorer in 1992 than in 1990, and in four of the NRA's then ten regions the compliance rate remained well below 40% in both 1991 and 1992.

These bald figures are not, however, a strictly fair comparison. Firstly, as the report notes, many consents for sewage works inherited by the NRA were not set on a "river needs" basis, but more reflected their operational capabilities.

Secondly, while consents for industrial discharges contain absolute limits, the water companies are still benefitting from the prosecution holiday given to their predecessors in 1985. Just before tighter legal controls were introduced on discharges under the Control of Pollution Act 1974, the Government amended their consents to provide that compliance would be achieved if 95% of the effluent samples taken over a rolling 12-month period met the consent limits.

The NRA attempted to claw back some of the lost protection by introducing absolute "upper limits" in sewage works' consents. However, the water companies have appealed against these, and the appeals have been waiting for a decision by the Department of the Environment since shortly after privatisation.

The report also notes that enforcing breaches of consents under the 95% compliance approach is difficult and time-consuming, in that "tripartite" effluent samples have to be taken over a 12-month period to provide the basis of a prosecution. However, the NRA adds that "in many cases" the initiation of tripartite sampling has provided the necessary stimulus for improvement.

The report goes on to outline the NRA's enforcement policy, and provides the first statistics on prosecutions for breaches of consent conditions. These totalled 84 in 1990, 132 in 1991, and 131 in 1992. The NRA's South West region was the least likely to resort to the courts, with just six prosecutions in the three years despite the poor performance of both sewage and industrial dischargers in its area.

Forthcoming developments in consent policy include:

  • A push for greater consistency in consent setting and monitoring across the NRA's regions after a discharge consents manual is issued later this year.

  • A possible move towards "composite" sampling, whereby several samples taken over a period will be combined into one to give a more representative picture of discharge performance. This change is being forced on the NRA by the 1991 EC Directive on urban wastewater treatment as far as sewage works are concerned, but a review of its merits for other types of discharge is also under way.

  • A move towards increased self-monitoring by dischargers, with the NRA focussing more on auditing their sampling and analytical practices.

  • Coupled with this, a move towards continuous effluent monitoring, backed up by devices to carry out automatic sampling of effluent which is shown by such monitoring to be in breach of consent conditions, thus providing a legally admissible tripartite sample. An automatic sampler of this kind has already snared one discharger (ENDS Report 217, p 44 ), and further field trials of the technology are under way.

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