Potential polluters in Northern Ireland

Advice on who is permitted to empty effluent into water industrial premises for potential polluters including: oil depots; timber treatment plants; chemical stores; farms; quarries; construction sites; and vehicle wash operators.

Permission to empty effulent

Under the terms of the Water (Northern Ireland) Order 1999, the Department of Environment must give permission before effluent can be emptied into a waterway, or into groundwater. Please contact the Industrial Discharges section for advice on completing applications and information on the management of effluent.

Potential water polluters include:

  • industrial premises
  • oil depots
  • timber treatment plants
  • chemical stores
  • farms
  • quarries
  • construction sites
  • vehicle wash operators

It is essential that drainage systems are used properly. For further advice see NIEA ‘ Proper use of Drains Leaflet ’.

Industrial premises

The main water pollution types associated with industrial premises are oil, sewage, chemicals and fine sediments.

Mallusk industrial survey

Mallusk Industrial Estate in Newtownabbey is a major industrial centre containing a wide range of businesses. The area contains several small streams draining into the river Blackwater, which is continually affected by various types of pollution. The estate's drainage network is complex - many of the streams have been diverted under roads, and as new sites are developed and premises change ownership, it is increasingly difficult to locate storm systems, foul sewers, and streams.

Companies may not be aware that their drainage is causing pollution and tracing the source and cleaning up becomes difficult when an incident occurs.

In 2000, the Water Management Unit carried out a survey of the area in order to improve knowledge of the drainage system, provide advice on pollution prevention and instigate legal proceedings where pollution incidents were discovered and traced.

The survey covered a very significant and expanding area. Liaison and follow up work continues and further site visits will be required to ensure that companies take appropriate action to minimise long term pollution risks.

Advice on preventing pollution from Industrial Premises can be found on GOV.UK:

Oil depots

The Pollution Prevention team is interested in auditing oil depots because of the toxic nature of oil in our environment. Oil is a toxic chemical. It forms a layer on the surface of rivers and lakes, reducing the amount of oxygen available for fish to breathe. It taints drinking water supplies and often makes sewage works inoperable.

The best way to prevent oil entering watercourses is to contain it. It is evident from pollution statistics that oil depots are not containing oil during its delivery, storage and distribution.

PPG 1, PPG 2, PPG 3, PPG 18, PPG 21 and PPG 26 advise on preventing pollution from Oil Depots. For advice on the construction of bunds please read our Masonry Bunds for oil storage tanks, and Concrete Bunds for oil storage tanks guidelines. These can be viewed or downloaded from our publications section.

Timber treatment plants

Timber is treated to preserve it against attack from the weather, pests (insects, fungi and bacteria) and fire. The process normally involves pressure impregnation and/or immersion of timber with either water, or organic based preservative, creosote or fire retardant.

Environmental impact of timber treatment fluid

The preservatives used include; Lindane, TBTO - Tributyl Tin Oxide, CCA - Copper Chrome Arsnic and Permethrin. These chemicals are highly poisonous to the insects and fungi they are designed to control but are also poisonous to a large range of non-target species including aquatic invertebrates and humans.

For this reason all precautions should be taken to protect public health and the environment from these substances when selecting a site for a new timber plant.

When these chemicals enter a watercourse three things happen:

  1. due to the poisonous nature of the chemicals, large numbers of non-target aquatic invertebrates are killed
  2. the accumulation of these chemicals in organisms higher up the food chain may kill them over a much longer period of time
  3. there has also been a proven link between the chemical Tri Butyl Tin (TBT in the antifoulant paint) and a hormone imbalance termed Imposex in dogwelks. The TBT causes a decline in the overall population.

A Code of Practice for safe design and operation of timber treatment installations was produced in 1998 to minimise the risk to surface and groundwater from these substances.

Chemical store

The BASIS (British Agrochemicals Standards Inspection Scheme) scheme is a system of self-regulation by the agrochemical industry for the safe storage and transport of agrochemicals. After assessment, BASIS issues certificates for stores and staff that meet the standards laid down in the FEPA Yellow Code.

Part III of the Food and Environment Protection Act 1985 (FEPA) includes strict controls over the storage of pesticides. The FEPA Code of Practice for suppliers of Pesticides to Agriculture, Horticulture and Forestry' (FEPA 'Yellow Code') and the Control of Pesticides Regulations 1986 require all reasonable precautions being taken to protect people, creatures, plants and the environment from pesticides.

At the BASIS scheme's introduction in 1978, only 0.5% of stores could be described as satisfactory by BASIS standards, whereas by 1999 the figure had risen to 99%.

In Northern Ireland, Water Quality Inspectors working with staff from the Fire Authority for Northern Ireland carry out BASIS inspections and certifications. A revision of the guidelines in 1999 now requires recertification ever five years.

Further advice can be viewed at the BASIS website.


At present we only provides advice on the prevention of pollution during certain disposal activities, e.g. the disposal of sheep dip to land - this requires the authorisation of the Department of Environment under the Groundwater Regulations (Northern Ireland) 1998.

Please contact the Groundwater Authorisations section for information on recommended good practice for the management of effluent and advice on completing applications.

In addition to this information, a number of publications entitled Good Farming Practice with regard to the environment are available from the Countryside Management Division of the Department of Agriculture and Rural Development (DARD).


The process of quarrying often involves the removal of rock and sediment that in some cases will be a reservoir for groundwater. To add to this, rainwater quickly becomes contaminated with silt, suspended solids and oil. These pollutants can destroy riverbed habitats, damage fish and reduce the amount of oxygen available in a watercourse.

The prevention of pollution from these sites is achieved by careful planning, installation and maintenance of well designed treatment facilities. This often proves to be a more cost-effective solution than receiving a fine for causing pollution and having to clean up the aftermath.

Advice on preventing pollution from Quarries can be found on the GOV.UK website:

Construction sites

Pollutants from these sites include silt/ suspended solids, concrete, chemicals and oil. Water from construction sites should never be pumped directly to a watercourse or be allowed to enter storm drains unless consent to discharge has been obtained from the Industrial Discharges section.

A waste management plan should be drawn up with the emphasis on reducing the volume of waste produced, reusing materials again or recycling them.

Advice on preventing pollution from Quarries can be found on the GOV.uk website. These can be viewed or downloaded from our publications section.

All responses will be used to help the regulators produce a draft PPG6, which will be circulated to key industry stakeholders for further comment in Summer 2009.

Vehicle wash operators

The effluent produced by vehicle wash installations is moderately toxic to aquatic life and will pollute any receiving watercourse.

Where feasible, it is recommended that this effluent should be connected to foul sewer for treatment and disposal, subject to permission being obtained from Northern Ireland Water website.

The Industrial Discharges section has produced A Guide for Vehicle Wash Operators which offers advice and information on discharging effluent from vehicle washes. Advice on preventing pollution from Vehicle Washes can be found on the GOV.UK website:

For further advice on pollution prevention issues please contact us to arrange a site meeting with our field staff, or ourselves.

Back to top