Environmental guidance for your business in Northern Ireland & Scotland

Trade effluent – Managing liquid wastes

What is trade effluent?

Trade effluent is any liquid waste (effluent), other than surface water and domestic sewage that is discharged from premises being used for a business, trade or industrial process.

Trade effluent can come from both large and small premises, including businesses such as car washes and launderettes. It can be effluent from the industrial or business process that is discharged into a public sewer, washed down a sink or toilet, or put into a private sewer that connects to the public sewer.

You will need to comply with legal restrictions regardless of how much trade effluent your business discharges.

Trade effluent may be waste water contaminated with materials such as:

  • fats, oils and greases
  • chemicals
  • detergents
  • heavy metal rinses
  • solids
  • food wastes

(Macerated food waste is banned from sewers in most cases from 1 Jan 2016 in Scotland, and from 1 April 2017 in Northern Ireland)

What is not trade effluent?

Liquid wastes which are not classed as trade effluent are:

  • domestic sewage, which includes wastewater from kitchen sinks, showers and toilets
  • clean, uncontaminated surface water, ie clean rainwater which has not been contaminated when running over your site

Additional resources

If your business produces trade effluent there are a number of ways that this can be managed.

  • If possible you should connect to a public sewer. This is the best option for treatment and disposal of trade effluent. If no public sewer is available you should look at connecting to the public sewer using a private sewer. You will still need a trade effluent consent or trade effluent agreement with your sewerage provider. Read the page in this guideline: Disposal to public sewer

 

  • Effluent that your sewerage provider will not accept. If you produce trade effluent that will damage the sewer, or would create risks for workers or the public you will not be able to discharge it to a public sewer. Read the page in the is Guideline: Dealing with effluent that can't go to foul sewers

 

  • Discharge to land. If no public sewer is available you must look at ways of treating your trade effluent before discharging it to land via a soakaway. Discharging treated effluent to land provides an extra level of treatment and is a better option than discharge to water. You will need an authorisation from the NIEA or SEPA before you can discharge your trade effluent to land. You will have to achieve a suitable level of treatment before any discharge will be permitted. Read the page in this guideline: Disposal to land where no public sewer is available.

 

  • Discharge to water. If a connection to a public sewer is not possible and there is not sufficient or suitable land for a soakaway, you may be able to discharge treated effluent directly to surface waters. If land is available for a reed bed or a gravel filter bed, then this can provide extra treatment to the effluent before final discharge. You must speak to the NIEA or SEPA to find out if this is suitable. Read the page in this guideline: Disposal to water, where no public sewer is available.

 

  • Treating your trade effluent. If you need to treat effluent before discharging it, you can use package treatment plants or septic tanks. Package treatment plants are generally more effective than septic tanks and achieve a higher quality of treatment. Where possible this should be connected to a soakaway, rather than directly to a watercourse. Read the page in this guideline: Using septic tanks and package treatment plants.

 

  • Improving the quantity and strength (concentration of substances) of your trade effluent. If you discharge to a public sewer the cost of sewerage services will depend on the volume of trade effluent you produce and what substances your trade effluent contains. You can reduce your costs by reducing the quantity of trade effluent you produce and by looking at ways of reducing the substances that enter the effluent. You could also consider treating it before it goes to sewer. If you cannot discharge to a public sewer and you want to discharge to land or to water, you can reduce the quantity or the strength of the effluent. This will make it easier to obtain the correct authorisation from the NIEA or SEPA. Read the page in this guideline: Reducing and treating your trade effluent

What you must do

You must get a trade effluent consent or enter into a trade effluent agreement with your water and sewerage company before you discharge any trade effluent to the public sewer.

This is important even if you only discharge a small amount of liquid waste, as it could cause serious damage to the sewage system and create a risk of danger to public health.

A trade effluent consent allows you to discharge liquid waste to the public sewer. This means that the contents of your trade effluent can be safely treated by the waste water treatment plant.

A trade effluent agreement is needed if your discharges contain substances that require work to be carried out by your water and sewerage company.

Apply to your sewerage provider for a trade effluent consent

You will need to apply to your water and sewerage company if you want to discharge trade effluent into the public sewer, or to a private sewer that connects to a public sewer

Northern Ireland: Find contact details for your water company on the Water UK website

Scotland: Find water company contact details on the Scotland on Tap website 

You may also need authorisation from the NIEA in Northern Ireland or SEPA in Scotland to discharge some trade effluents to sewer. These include effluents from installations that have a pollution prevention and control (PPC) permit. You must comply with any requirements on your permit for discharging effluents

Contact your environmental regulator

If your effluents are unsuitable for discharging to the public sewer, or there is no public sewer available, you could:

  • change your process so you do not produce the effluent or certain substances
  • treat the effluent on site before discharging it to a sewer
  • pay for it to be taken away for off-site treatment.

If you cannot discharge an effluent to the public sewer it will be classed as waste. You must comply with your duty of care responsibilities when dealing with your waste.

Duty of care – your waste responsibilities.

Your water and sewerage company may not accept discharges of effluents that contain substances which may harm the sewer or treatment process, or be harmful to human health. Harmful substances include:

  • oil and fats
  • solvents
  • working solutions containing heavy metals
  • complex organic mixtures
  • flammable materials
  • liquids with a very high or a very low pH
  • other materials likely to damage the sewer, or harm people working in the sewer.

Your water and sewerage company will advise you if your effluent can be accepted to the public sewer. If it cannot be accepted, you will need to consider other options for treatment or disposal.

You might be able to pump your trade effluent to the nearest public sewer.

Alternatively you may be able to treat the effluent on site before discharging it to land using a soakaway.

What you must do

Before you discharge treated trade effluent you must have:

  • in Northern Ireland a discharge consent, groundwater authorisation or pollution prevention and control (PPC) permit from the Northern Ireland Environment Agency (NIEA)
  • in Scotland an authorisation under the Controlled Activities Regulations (CAR). CAR requirements are also met within authorisations under  pollution prevention and control (PPC) permit, Waste Management Licence (WML) or the Radioactive Substances Act from the Scottish Environment Protection Agency (SEPA).

If you have an authorisation (including consent, licence or PPC permit) it will specify the maximum concentrations of pollutants allowed in the effluent. You will need to decide how to achieve these limits. You may be able to change your processes, or you could consider using an effluent treatment system. 

See the page in this guideline: Using septic tanks and package treatment plants.

You must not discharge trade effluent to land without prior permission.

If you are setting up a new business you should investigate effluent disposal before you choose the location of your business.

Further Information

Preventing water pollution

PPG4: Treatment and disposal of sewage where no foul sewer is available (PDF 245 KB) [PPG under review]

DOENI: Regulating Water Discharges

Septic tanks

You might be able to pump your trade effluent to the nearest public sewer.

Alternatively you may be able to treat the effluent on site before discharging it to surface waters or groundwater.

What you must do

Before you discharge treated trade effluent you must have:

  • in Northern Ireland a discharge consent, groundwater authorisation or pollution prevention and control (PPC) permit from the Northern Ireland Environment Agency (NIEA)
  • in Scotland an authorisation under the Controlled Activities Regulations (CAR). CAR requirements are also meet within authorisations under  pollution prevention and control (PPC) permit, Waste Management Licence (WML) or the Radioactive Substances Act from the Scottish Environment Protection Agency (SEPA).

If you have an authorisation (including consent, licence or PPC permit) it will specify the maximum concentrations of pollutants allowed in the effluent. You will need to decide how to achieve these limits. You may be able to change your processes, or you could consider using an effluent treatment system (such as package treatment plants or septic tanks).

If possible you should look at the possibility of using a soakaway to land. This requires a large enough area of land to be available. The land must also be well drained, not waterlogged, and have a sufficient depth of soil. If no land is available then additional treatment can be achieved using reed beds or gravel filter beds, though these are not usually accepted in Northern Ireland.

You must not discharge trade effluent into a surface water drain, surface waters or groundwater without prior permission.

If you are setting up a new business you should investigate effluent disposal before you choose the location of your business.

Further Information

Preventing water pollution

PPG4: Treatment and disposal of sewage where no foul sewer is available (PDF 245 KB) [PPG under review]

DOENI: Regulating Water Discharges

Septic tanks

If your business is in an area where no mains sewers are available, you may need to treat your effluent on site before discharging it to surface waters or groundwater. You may need to use a wastewater treatment system such as a package treatment plant, septic tank or cesspool. (Note that you are not allowed to use cesspools in Scotland)

What you must do

Septic tanks and package treatment plants

Septic tanks provide basic sewage treatment. You should make sure the effluent from your septic tank is further treated - eg by a soakaway or (in Scotland) using a filter or reed bed - before you dispose of it to a watercourse.

You should make sure that your soakaway, also known as a drainage field, conforms to the British Standard:

BS 6297 Code of practice for the design and installation of drainage fields for use in wastewater treatment

Septic tanks must be installed following the standards set out in the building regulations.

In Northern Ireland:

The Building Regulations (Northern Ireland) 1990 Technical Booklet N

Also available from The Stationary Office, Belfast on 02890 238 451

In Scotland:

Scottish Government: Technical Handbook – Domestic - section 3.9

Package treatment plants

Package treatment plants are available in different sizes, suitable for dealing with different volumes of effluent.

Correctly operated and well-maintained package treatment plants produce a higher quality effluent which you may be able to discharge to surface water or groundwater.

You will need to carry out a percolation test if you want to use a soakaway or drainage field to dispose of the effluent from your septic tank or package treatment plant. This will confirm whether the area is suitable for a soakaway and will determine the size of the drainage area you need.

PPG 4 Treatment and disposal of sewage where no foul sewer is available (Adobe PDF – 244KB)(under review)

If you plan to install a new system or alter your existing system of sewage disposal, you should contact your environmental regulator at an early stage to discuss your plans.

Using a soakaway

You may be able to dispose of the septic tank effluent by soaking it away to ground, for example by using a herringbone drainage field, if you have sufficient land and the drainage conditions are favourable. Permission to do this will depend on the distance of your septic tank from local groundwater sources and other protected areas. You should read our more detailed guidance on septic tanks, or contact your environmental regulator for advice.

Septic tanks

Contact your environmental regulator

Get authorisation for your septic tank or package treatment plant

Before you discharge any sewage, effluent or contaminated run-off to land, surface waters or groundwater you must have:

  • In Northern Ireland: a discharge consent, groundwater authorisation or pollution prevention and control (PPC) permit from the NIEA
  • In Scotland: an authorisation under the Controlled Activities Regulations (CAR). CAR requirements are also meet within authorisations under pollution prevention and control (PPC) permit, Waste Management Licence (WML) or the Radioactive Substances Act from the Scottish Environment Protection Agency (SEPA).

You will not normally get an authorisation to discharge if it is reasonable for you to connect to the public sewer.

You may need a waste management licence from the NIEA or SEPA if you treat effluent from another business' site.

In Scotland, if you need to construct a new outfall structure for your discharge your discharge authorisation will cover the construction.

In Northern Ireland, the construction of a new outfall structure is not covered by the discharge consent. This consent only regulates the discharge itself. Consent under Schedule 6 of the Drainage (Northern Ireland) Order 1973 will be needed from the Rivers Agency for any works likely to affect any watercourse, which may included the construction of an outfall pipe.

Cesspools

A cesspool is a watertight tank with no outlet. You are not allowed to use a cesspool in Scotland.

You will need to empty your cesspool regularly to prevent it overflowing. Fit an alarm that will go off when your cesspool is nearly full. This is an emergency back-up and you should check the tank regularly.

Maintain your wastewater treatment system

Follow the manufacturer's operating and maintenance instructions to make sure that your wastewater treatment system operates effectively.

You must use a registered waste carrier to remove sludge from your septic tank or treatment plant.

NIEA Registration of Carriers for information

SEPA: Who is registered?

You should make sure that clean surface water run-off, eg from roofs and parking areas, does not enter your treatment system. The extra water will reduce the effective capacity of the system and may flush solids out.

Read the next section on avoiding spills and unauthorised discharges.

Further information

NetRegs: Septic tanks

PPG 4 Treatment and disposal of sewage where no foul sewer is available (Adobe PDF – 244KB)

Preventing water pollution

Reducing and treating your liquid waste can lower your trade effluent bills. You can cut costs by:

  • reducing the amount of wastewater you generate overall
  • reducing the strength (concentration of substances) of your trade effluent
  • reusing wastewater wherever possible.

To reduce costs you could consider:

  • checking your meters and meter readings are accurate, especially at sites with more than one trade effluent discharge consent
  • mixing a higher strength discharge with a lower strength discharge
  • evaluating whether an effluent stream from one process can be reused as an input to another process
  • treating effluents prior to discharge - eg simple physical or chemical treatment of an effluent stream before discharge to sewer will lower the cost of further treatment by the water company
  • treating a higher strength effluent to recover for reuse a raw material that would otherwise have been disposed of
  • ensuring that the composition or volume of effluents does not breach your consent, as you could be prosecuted and fined
  • reducing water use to cut your meter charges and your wastewater bill

Water use and efficiency

Install effluent treatment systems

The cost of discharging trade effluent to a sewer is based on the volume discharged and the concentration of contaminants, so it could be worth installing some form of preliminary treatment system. For example, a simple sedimentation tank could remove a large percentage of the suspended solids in the effluent.

You must comply with your duty of care responsibilities when you dispose of waste from an effluent treatment system. This means you must ensure your waste is handled, recovered and disposed of correctly.

Duty of care - your waste responsibilities

You need to manage and regularly maintain treatment systems to ensure that they are working correctly

Some systems are so effective that you might be able to recover and reuse the effluent on site, saving more water and discharge costs. You may also be able to recover raw materials that could be reused.

Establish effluent discharge procedures

Make sure that your staff record the effluents being discharged accurately, particularly if they are responsible for emptying and discharging effluents from specific processes.

If any new processes are added, this will add to the volume and contaminants being discharged. Check the effluent produced to ensure that your consent is still valid.

Have a site plan that identifies all access and entry points to the sewerage system. Workers responsible for discharging effluents should be made aware that the access and entry points are specifically for trade effluents only.

Make sure that any surface water drains cannot be mistaken for drains that lead to the sewer.

You must have permission from your water and sewerage company before you discharge any trade effluent to the public sewer. The following measures will help you to minimise the chances of making any discharges accidentally.

Keep a drainage plan of your site

Make sure you have an up-to-date and accurate drainage plan of your site. This will help you identify the locations of all the drains and sewers and where they lead.

You should discharge all trade effluent and sewage to the public sewer. Only discharge clean, uncontaminated water to the surface water drainage system.

Paint the drainage system manhole covers, gullies and grills on your site in the recognised colour-coding system - blue for surface water drains and red for foul water drains, or combined drains. This will help you identify where any spills will end up.

Manage your materials and practices effectively

Investigate alternative materials and practices that do not produce effluents, eg reuse water for rinsing and cleaning where possible.

Store and handle raw materials, wastes, chemicals and fuels responsibly, so that they cannot enter the surface water and foul water drains on your site. See our guideline:

Chemical storage

Keep spill kits near to where you might need them with clear instructions for their use. Make sure your staff know where they are and how to use them.

Spill kits might contain:

  • absorbent materials, eg sand
  • containment equipment, eg booms
  • pumps and suction equipment
  • pipe blockers
  • drain mats.

Make an inventory of all the equipment and materials you have on site. These should be suitable for the type and quantity of fuel, oil and chemicals you store and use.

See our guideline: Preventing water pollution.

Ensure you make any visiting contractors aware that they must not discharge any effluents to sewers without checking first that they can.

Contain spills

You must contain any spills and prevent them from entering site drains. You should also:

  • prepare a pollution incident response procedure for dealing with spills
  • train your staff so that they are aware of the spills procedure
  • report all pollution incidents as soon as they happen to the Northern Ireland Environment Agency (NIEA) or the Scottish Environment Protection Agency (SEPA) - you can call the UK wide Water Pollution Hotline on Tel 0800 80 70 60
  • inform your water and sewerage company trade effluent officer if you have any spills on your site
  • use impermeable upstands around foul water drain entry points to prevent accidental discharge of effluents that are not authorised by your water company or authority - this includes contaminated surface water
  • tell your employees and contractors about your procedures for handling, disposing of and discharging liquid wastes - make sure that they comply with them.

This page provides links to the full text of key pieces of environmental legislation relating to trade effluent. The websites hosting the legislation may list amendments separately.

If you are setting up an environmental management system (EMS) for your business, you can use this list to start compiling your legal register. Your legal adviser or environmental consultant will be able to tell you if other environmental legislation applies to your specific business.

Environmental management systems and environmental reports

Northern Ireland Legislation

Water (Northern Ireland) Order SI 1999/662. Makes provision for discharge consents. Enables the Department of Environment to set water quality objectives and prevent pollution from anti-pollution works.

Water and Sewerage Services (Northern Ireland) Order SI 2006/3336. Establishes government-owned companies' obligations for water supply, drinking water quality, trade effluent and sewage disposal, water and sewerage charges and customer service.

Scottish Legislation

Sewerage (Scotland) Act 1968. Requires the water and sewerage undertaker to provide public sewers as necessary for domestic sewage, surface water and trade effluent. Regulates discharges of trade effluent by grant of consent or by agreement.

Control of Pollution Act 1974. Sets out legal framework for controlling trade effluent discharges into public sewers.

Water Environment (Controlled Activities) (Scotland) Regulations SSI 2011/209. Replaces 2005/348 (as amended). Increases the transparency and efficiency of processing applications for water use licences, and introduces greater flexibility to deal with emergency situations where there are imminent risks of serious harm to people, property or the environment.

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