Surface Water, Domestic Sewage and Trade Effluent – What’s the difference?

Wastewater is the term usually used to describe any water that has been used and is discharged back to the sewer or the local environment. It can be relatively clean and returned to the environment, for example rainwater that runs off your land straight into a stream or soakaway. At the other end of the scale, it can come from an industrial process and be discharged to the sewer contaminated with chemicals or biological matter. To help explain the differences between each one, we’ve included some descriptions of the main types of wastewater, with a focus on Trade Effluent.

Domestic Sewage

Domestic sewage is simply pee, poo and toilet paper. These are the only things that should be discharged into our sewer systems as these are the things the sewerage network and treatment process is designed to cope with. Some other wastewater from domestic use such as bath and shower water are ok to be discharged to the sewer too.

Surface Water

Surface water comes from rainfall that hits your site and ends up in the sewer or back in the environment. For example, grassy areas allow rainwater to soak into the ground and it is then passed back into the environment. On the other hand, paved areas or buildings with guttering will channel the rainwater and return it to the sewer. Despite starting out relatively clean, surface water can be contaminated when it comes into contact with other substances such as oil and grit on the ground.

Trade Effluent?

Trade Effluent is wastewater produced as part of a trade process, at a trade premises, that is discharged to the public sewer. The Water Industry Act (1991) defines it 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.”

We recognise this definition is quite broad and can be applied to a wide range of different trades, including:

  • Vehicle washing facilities
  • Wheelie bin cleaning companies
  • Swimming pools
  • Laundrettes
  • Abattoirs
  • Foundries
  • Pharmaceutical Companies
  • Chemical Works
  • Contaminated surface water

Is Trade Effluent waste harmful?

Trade Effluent is often believed to be harmful or toxic, but this isn’t always the case. It can simply be water that has been involved in a process, but if it meets the definition above, you’ll need to seek consent before you’re able to discharge it into a public sewer.

Some sites do have sewers that discharge directly to watercourses. These are usually used to discharge surface water that would otherwise take up unnecessary space in the sewer. To discharge effluent waste via these sewers, permission would be required from the sewerage undertaker and the Environment Agency.

All wastewater has the potential to be harmful to health and the environment, so it must be managed correctly. Most wastewater is transported via sewers to sewage treatment works, where the harmful components and solids are removed. It’s then given a final polish and then returned to a watercourse.

Trade Effluent Consent

Although not domestic sewage, it is not illegal to discharge Trade Effluent as long as it’s done with the permission of the sewerage undertaker (wholesaler). To get this permission, you need to apply for, and be granted, permission via a legally binding document known as a Trade Effluent Consent.

Applying for Trade Effluent Consent

The requirements and legislation can be complex but at Wave, we regularly provide our customers with support when applying for the necessary consent. You can download the G02 form and guidance notes on how to complete the form, here.

Once the application is made, the sewerage undertakers have two months to review it and decide whether to grant or deny consent. To help make the process as straightforward as possible, it’s important you fill in your application form accurately and always include comprehensive answers. Some of the key factors the undertakers will need to assess are:

  • Where the wastewater will be discharged (in relation to the public sewer location)
  • Where the Wholesaler can take a sample of the effluent water from
  • Volume of discharge expected per day to ensure the treatment works has capacity
  • What is the flow rate to discharge to ensure the sewers can handle the instantaneous volume
  • What processes the Trade Effluent comes from
  • What components make up the effluent (chemical, biological, physical parameters)
  • Whether there is anything harmful in the effluent

Your application must include a site plan so the undertakers can see the connection to the public sewer and where the sample point will be. Keep in mind the sample must be a representative sample of the effluent itself and not be contaminated with domestic sewer or other waste. As it’s a legal document, the application must be signed off by someone with the correct authority to do so.

Trade Effluent Grey Areas

Sometimes it can be difficult to know whether you are discharging Trade Effluent or not. For example, wastewater from hairdressers, car washes and mobile activities such as wheelie bin cleaning may sometimes be classed as Trade Effluent and sometimes not. Something classed as Trade Effluent in one region may be excluded in another. The key point is if you’re unsure, you must ask your water retailer to ask the wholesaler and find out for you. At Wave we can make enquiries on your behalf so you can be sure whether you need permission to discharge your wastewater. Being upfront and transparent is the best policy to ensure you are acting within the law.

Exceptions to Trade Effluent

One important exception to the usual permissions is wastewater from restaurants and takeaways. Technically, this should be classed as Trade Effluent as it meets the definition. However, in reality, a formal Consent is unnecessary in terms of the risk to the sewerage network. The Water Industry Act does make it an offence if something is discharged into the sewer that causes problems (for example waste oil from a takeaway causing sewer blockages). Businesses that don’t require a Consent could still be fined or prosecuted if they pour something down the drain or sink that they shouldn’t. Your water retailer can advise on ways to avoid this and you should follow best practice in relation to your wastewater at all times.

Supporting our customers

At Wave we have years of experience helping businesses manage their Trade Effluent and our team of experts are here to offer support. If you believe you need to apply for, or make changes too, a Trade Effluent discharge please visit this page of our website. As well as downloading the form, you’ll also find some guidance notes to support you while you’re completing the form. Once completed we’ll be happy to accept your form and review your application as quickly as possible before submitting it to the wholesaler on your behalf, once it’s approved.

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