Advice Articles

A Guide To Trade Effluent

top view of concrete structures

Learn how to dispose of liquid waste properly — and stay on the right side of the law

As a householder, you don’t need to think about waste disposal. By the time you buy or lease your home, its kitchen and bathroom wastes are already hooked up to local authority sewers. All you ever need to do is pay your Council Tax and maybe unblock your sink once in a while.

When you run a business, that changes. You’ll likely find that you’ve become a producer of ‘trade effluent’, defined under the Water Industry Act (1991) 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.”

But there are a few exceptions. If you provide kitchen sinks, showers or toilets for your staff or customers, the water that comes out of them will still be classified as ‘domestic sewage’. Hotels, pubs, restaurants and caravan parks may also have similar exceptions apply, although disposal of food wastes in sewage is strictly prohibited. You also won’t carry any special responsibility for rainwater runoff, as long as you don’t contaminate it.

However, if you’re responsible for effluent that doesn’t fall under these definitions, you’ll need to think carefully about disposal methods. Even if you believe you’re one of the exceptions, it’s a good idea to do a bit of homework to ensure that your discharges are legal as well as cost-effective.

This handy guide to trade effluent will point you in the right direction.

What are my options?

Producers of trade effluent have four basic means of disposal:

  • Public sewers
  • Discharge onto land
  • Discharge into water
  • Collection by contractor

(Quick tip: if at all possible, pick option 1!)

Discharging into the public sewer

The public sewer will always be your cheapest and most convenient disposal option… but you’ll need to co-operate with the relevant authorities. They may even allow you to route your waste directly into the nearest available pipe, just like you do at home. If you’re among the lucky ones, your local sewerage undertaker will issue the relevant certificate of Trade Effluent Consent.

Plenty of businesses are less fortunate. If you work with chemicals or metals, process food and drink, or operate a car wash or launderette, you’ll need to upgrade that Consent to a Trade Effluent Agreement. The sewerage company will carry out a detailed analysis of your outflows and apply something called the Mogden Formula to calculate how much you’ll need to pay. You may also need additional consents and/or permits from environmental regulators, usually chargeable.

Reducing sewerage costs

If you’ve been asked to pay for use of the public sewer, you may be able to get those payments reduced. This will involve processing your effluent to reduce its total volume or level of contamination, and thereby reducing your Mogden Formula contributions. There’s more about on-site processing in the sections which follow.

The ‘liquid waste’ designation

It’s not uncommon for sewerage undertakers to refuse their consent to a particular business, either because it produces effluents contaminated with toxic substances, or because its contents are likely to damage infrastructure.

If you get such a refusal, your effluent will likely be reclassified as ‘liquid waste’.

Discharging onto land

Many businesses whose product has been classified as liquid waste opt to discharge into a soakaway or similar. Such arrangements, governed by the Environmental Permitting Regulations (2016), are likely to be more complex and expensive than sewer-based disposals.

Firstly, you’ll need to approach the relevant national agency — the Environment Agency for England and Wales, the Scottish Environment Protection Agency (SEPA) or the Northern Ireland Environment Agency (NIEA) — with an application that demonstrates that you’ve put in place appropriate processes to treat and monitor your effluents.

But what exactly is an ‘appropriate process’?

So-called ‘package treatment plant’ installations come in all shapes and sizes. Some are intended for pre-processing effluents that are headed for the sewers, and others for on-site treatment prior to local discharge.

If you’re processing organic waste, the minimum viable solution will usually be a septic tank populated with anaerobic bacteria and connected to a British Standards-compliant soakaway.

If you need to discharge onto land and have lots of space to play with, you may prefer a gravel or reed bed — effectively a small expanse of wetland where biological processes can work their purifying magic. As you might expect, these solutions require well-drained soil and specialist input.

Whichever route you go down, you’ll also need carefully defined management processes to sample, monitor and record whatever it is you’re putting into the environment. If it’s all a bit much, seek guidance from the regulator.

Discharging into water

The most problematic of the options set out at the top of this article is that of discharging into water.

In essence, the considerations for a business going down this route are the same as those of the previous section. However, discharging into a lake, a river, or the sea has some stringent requirements.

Expect a grilling from the relevant authority, and be sure to prepare a ‘Plan B’.

Off-site disposal

What happens if you’re not allowed to adopt any of the three previous disposal options? Here’s where Plan B comes in…

Some kinds of liquid waste are simply too dangerous to be discharged into the environment. A good (but outdated) example would be the chemically-contaminated water that used to emerge from big photographic processing plants. The only sensible course of action in such cases is to send the waste offsite for specialist processing.

Such arrangements will require you to install an onsite cesspool, that is, a sealed tank which is emptied regularly. You’ll also need to inform the relevant agencies and set up an overfill alarm as part of your management policies. In Scotland, cesspools are banned absolutely, and in some other parts of the UK their use is regulated.

For further information:

Environment Agency (England and Wales) https://www.gov.uk/government/organisations/environment-agency

Scottish Environment Protection Agency (SEPA) https://www.sepa.org.uk/

Northern Ireland Environment Agency (NIEA) https://www.daera-ni.gov.uk/northern-ireland-environment-agency