In this expert guide the industrial wastewater specialists at Water Treatment Services take a detailed look at issues associated with the treatment of trade effluent and management of liquid waste in commercial, industrial and process environments.
The guide looks at what options businesses have in dealing with their liquid wastes, the regulatory environment and discharge consent process.
It goes on to examine how businesses can improve the management, disposal and re-use of their effluent to reduce costs, improve environmental performance and meet their discharge and regulatory compliance obligations.
What is trade effluent?
In the UK trade effluent is defined as any liquid waste, other than domestic sewage or rainwater run-off which comes from a business.
Any size or type of business can produce trade effluent during the course of its day-to-day activities, and this could range from a single-person car wash operation or a small launderette, to the largest of manufacturing facilities.
This liquid waste or effluent might then be washed or discharged into the public sewer system, or into the business’s own wastewater treatment plant which then connects in to the public network.
The Water Industry Act 1991 defines trade effluent as “any liquid, either with or without particles of matter in suspension in the liquid, which is wholly or partly produced in the course of any trade or industry carried on at a trade premises.”
In the UK and many other countries around the world there are strict regulations about what trade effluent is, and how businesses deal with it.
In most cases, effluent is described as water which is contaminated with chemicals, metals, detergents, fats, grease or food waste.
There are also strict rules on businesses preventing the use of macerator machines which grind up food waste before it is discharged into the public sewer system.
Do you need consent to discharge your trade effluent?
If your business makes or uses products like chemicals, metals, food and drink, or if you operate a car wash or launderette, it’s likely you’ll need a trade effluent consent from your Sewerage Undertaker.
Short-term effluent discharges involving contaminated groundwater from construction projects or the flushing of building services water systems such as central heating or chiller systems will also usually need a temporary trade effluent consent.
Some types of water and liquid waste produced by businesses including hotels, pubs, restaurants, takeaways and caravan parks isn’t currently classed as trade effluent.
Water from kitchen sinks, showers or toilets which you have on site for staff or customer use is not considered as trade effluent, being classed as domestic sewage.
Rainwater which falls on roofs, car parks or business premises and then passes into surface water drains isn’t trade effluent either.
However, these businesses are still regulated under Section 111 of the Water Industry Act 1991 and if they are found to be discharging fats, oils, greases and food into the sewer they can be prosecuted.
How to deal with trade effluent?
If your organisation produces trade effluent or liquid waste there are a number of ways of dealing with it.
The best, and most cost effective option is to connect to a public sewer, although before you do this you’ll need specific consent from the water company which provides your sewerage services to do this.
If this isn’t possible the next best option is to operate your own private sewer running through your business premises, which connects up to the public sewer system as near to your land as possible.
Sometimes however, a sewerage company (the Sewerage Undertaker) will refuse to deal with your trade effluent.
This is usually because it is contaminated with something which may pose a risk to people or because it could damage the inside of the sewer pipes or other parts of their infrastructure. In these cases, you will have to make alternative arrangements for the disposal of your trade effluent.
Effluent which is unsuitable for discharge to the public sewer, or in cases where no public sewer is available, is often discharged onto land through a soak-away.
Companies which use this method to get rid of wastewater and trade effluent have to make sure it is treated properly before being discharged.
To discharge wastewater or liquid effluent in this way you will need to get permission from the Environment Agency in England and Wales, the Scottish Environment Protection Agency (SEPA) in Scotland or the Northern Ireland Environment Agency (NIEA) before doing this, and prove that you have processes in place to treat and monitor the quality of the effluent effectively.
Businesses might also choose to discharge trade effluent into waterways such as lakes, rivers, canals, estuaries or even the sea. Again, businesses planning on doing this need to get permission from the appropriate authorities first.
Companies which are required to treat their trade effluent before disposing of it generally use special wastewater treatment plant installations designed or selected to deal with their type and volume of effluent.
These are often more effective than septic tanks, and the effluent can be treated so it is less contaminating. Package water treatment plants are usually connected to a soak-away rather than directly to a river or the sea.
How are trade effluent charges calculated?
If your trade effluent flows into the public sewer, the cost of your sewerage will depend on the level of contamination, and the volume of trade effluent the business produces. UK Sewerage Undertakers use a special formula called the Mogden formula to calculate what you will pay.
For most businesses there are three main components of their liquid waste that they can control to help optimise their effluent charges, they are:
- Volume of effluent to be discharged
- Chemical Oxygen Demand (COD) of the effluent
- Suspended Solids (SS) content
If you can reduce the volume of effluent, or the level of contamination, discharge costs will come down. Costs can also be reduced by introducing some form of water treatment process before the effluent finally flows into the public sewer.
Discharging trade effluent to a public sewer
It is important to remember that you need consent from the company which provides your water and sewerage services before discharging trade effluent into a public sewer.
This is the case even if the amounts of effluent your business is producing are very small. It is an offence under section 118 of the Water Industry Act 1991 to discharge trade effluent without consent and this could lead to enforcement action being taken and possible prosecution.
If your business’s effluent requires extra work on the part of the water company, then you will need a trade effluent agreement as well as consent. Contact your water company in the first instance and discuss your options.
In some cases, you will need additional consent from the environmental regulators in England and Wales, Scotland or Northern Ireland if you plan to discharge trade effluent into the public sewer. You may also be asked to pay for a permit to prevent and control pollution.
Options for dealing with trade effluent not suitable for public sewers
If your water company is not prepared to grant consent to put your wastewater or trade effluent directly into the public sewerage system, then you have a range of options. These options include:
- Paying a contractor to take the effluent away and treat it for you.
- Treat it yourself on site to make it suitable for discharge to a sewer.
- Adapt your business operations to clean up the effluent and make it suitable for discharging into a sewer.
Effluents which aren’t safe enough to put into the public sewer system are classed as liquid waste.
Water companies produce long lists of various contaminants which, if present in your trade effluent, could mean it is not suitable for discharging to a public sewer.
This includes fats, oils, solvents, anything flammable, anything which makes the effluent excessively acidic or alkaline, heavy metals, or anything else which could damage the sewer system, harm sewerage workers, or compromise final water quality.
Your water company makes the decision about whether or not to accept a business’s trade effluent into the public sewer. Unfortunately, if they refuse, your only option is to consider alternative options for treating or disposing of it.
Disposing of trade effluent on land and the Environmental Permitting Regulations
In some cases, it might be possible to send trade effluent off-site to the nearest public sewer. If that is not possible, then another option is to treat your trade effluent on site and then discharge it through a soak-away.
Under the Environmental Permitting Regulations 2016 consent to deal with trade effluent in this way must be obtained from your local environmental regulator, in England and Wales this will be the Environment Agency.
In Northern Ireland you will need consent from the Northern Ireland Environment Agency (NIEA) and in Scotland, from the Scottish Environment Protection Agency (SEPA).
Once your licence has been granted by the appropriate agency, it will specify minimum standards that must be met including the maximum concentration of contaminants in the wastewater or effluent. The company has flexibility over how these limits are achieved.
Most businesses use a combination of measures such as pre-treating trade effluent, or installing an effluent treatment plant system.
Remember that businesses are not allowed to discharge trade effluent onto land without getting permission first. When relocating or setting up a new business, consider how you are going to dispose of your trade effluent as this could affect the location of your operations.
Disposing of trade effluent to an existing water course
Similar rules apply to businesses who plan to discharge their trade effluent into an existing watercourse, this could mean a river, estuary, lake, canal or the sea.
Consent must be obtained from the relevant environmental body, which will specify minimum standards for trade effluent going into water.
Soakaways are usually the best way of dealing with trade effluent in most cases. Land which is used for the disposal of trade effluent has to be well-drained. There should also be a minimum soil depth.
Some operations use gravel beds or reed bed filters to treat the trade effluent before it flows into the watercourse.
Anyone setting up a new business or considering relocating should think about these issues before deciding on a location for their business.
Using water treatment plant and septic tanks
Septic tanks are a very basic way of treating sewage and trade effluent. Water usually needs to be treated in some other way as well before it reaches the standards required to be discharged into a watercourse or public sewer system.
If you’re planning on using a soakaway to do this, make sure it conforms to the appropriate British Standards, and consult the current Building Regulations to find out about the standards required when installing septic tanks.
Package treatment plant installations come in a range of different types and sizes, and should be selected to suit the different forms of effluent and daily volumes a business might produce, both currently, and in to the future to allow for expansion.
If you are running your wastewater treatment plant efficiently, the effluent can be cleaned up to meet the standards needed to discharge it into water.
Soakaways can also be used with septic tanks if you have enough well-drained land. You will have to get permission to do this, and the decision will be based on local geography and the distance of your septic tank from local groundwater.
To get some initial advice you can speak to your local environmental regulator.
Cesspools are a slightly different way of dealing with effluent.
A cesspool stores effluent but does not treat it. It will need to be emptied regularly. Regulation in Scotland bans the use of cesspools, and in other parts of the UK they should only be used as an emergency back-up.
From 1 January 2020, septic tanks must not discharge directly to a watercourse and operators should make alternative arrangements for disposal.
Treating trade effluent and liquid waste
If you take steps to reduce the amount of liquid waste your business produces, and make the wastewater cleaner, this can dramatically reduce your disposal bills.
This can be done by reducing the overall volume of wastewater, reducing the levels of substances in the waste including suspended solids, tackling chemical oxygen demand (COD) in your effluent, or reusing your wastewater for alternative purposes.
There are lots of other things your business could consider to help cut its effluent discharge costs.
For example, mixing heavily contaminated effluent from one part of the operation with water from elsewhere which is less contaminated.
You could also choose to filter or chemically treat effluent on-site to reduce the levels of suspended solids, improve COD and clean it. You could also consider reducing the amount of clean water you use as part of your processes so there is less wastewater produced.
Wastewater and effluent treatment systems
Your sewerage charges for disposing of trade effluent are based on a number of factors already covered here, but the main elements include the volume of wastewater you produce and how contaminated it is.
It might be worth installing additional onsite processes to treat the liquid waste before it enters the sewerage system. Even something as simple as a sedimentation tank can remove a lot of suspended solids in the water and therefore reduce your disposal bills.
Organisations have to take responsibility for managing and maintaining any water treatment systems they use and the quality of the effluents they look to discharge.
Depending on your processes and how effective your wastewater treatment systems are, you might be able to reuse the effluent waters you produce in other parts of the business to save you both money and water.
It is also important that businesses and plant operators introduce processes to sample, monitor and record the quality and quantity of effluent being discharged. This would include levels and types of contamination.
Additionally, if a business changes the way it operates, then you should also assess the impact this might have on the quality and volume of your trade effluent.
Avoiding on-site spills and what to do if one occurs
You need to have permission from your water company before starting to discharge trade effluent into their sewerage system. Part of your responsibility is to minimise the risk of accidental on-site spillages and have an action plan if one does happen.
Businesses should keep an up to date site plan, with the positions of all drains and sewers clearly marked. Staff should also know what liquids or materials may be involved in a spill, with access to up to date Safety Data Sheets (SDS).
Steps should be taken to make sure that only clean water goes into surface water drainage, and trade effluent goes into the public sewer.
Companies usually colour code the various drains and outlet grilles they have on their premises. Blue is typically used for surface water, and red for foul water.
It also makes sense to look into alternative ways of doing things, including ways of reusing water where possible.
Spillage kits containing sand, absorbent granules, suction equipment, drainage blockers and other items should be kept in areas where spills are more likely to happen.
Staff should also be trained when and how to use them properly.
If a spill does happen, staff should be trained to step in to contain spills and stop them from getting into drains and cause unwanted pollution.
Staff should be trained so they know what to do and know who they should report the spill to if one happens.
Most companies have a person designated within the operation to take charge of all issues with water and effluent, including training.
It is also recommended that the sewerage undertaker is informed if an accidental spill occurs, giving them details of the substances involved, location of the spillage, likely quantities discharged and what you did to minimise the problem.
UK environmental legislation
Each part of the UK has its own legislation about managing trade effluent and the rules and regulations to be followed. For more detailed information you can review the following websites:
- Environment Agency
- Scottish Environment Protection Agency (SEPA)
- Northern Ireland Environment Agency (NIEA)
Specialist trade effluent and industrial wastewater solutions
Water Treatment Services offer a comprehensive range of trade effluent and liquid waste management solutions. Find out how we can help reduce your costs, achieve regulatory compliance and improve environmental performance.
Our experts can provide advice and full support to help you identify the most appropriate strategies for managing your liquid waste and effluent streams.
With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained engineers, wastewater specialists and technicians we offer cost effective environmental support solutions across the whole of the UK and Ireland.
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