If you’re a manufacturer, be it of cars, sausages, beer or paracetamol, irrespective of what you manufacture you will almost certainly be producing trade effluent.

What is trade effluent?

Trade effluent is classed as any effluent produced from a process or activity undertaken at an industrial or trade premises, including airports and hospitals. In order to legally discharge trade effluent, you must obtain a consent licence from your local water authority and fully comply with its specific conditions. Spills, pollutions or any other breach of the licence will result in costly fines and damaging PR for your business or brand.

Explains Phill Tuxford, technical support manager at Detectronic: “It might sound obvious but it’s vital that once you have a consent licence you actually read it and review it on a regular basis. Is the licence appropriate to your business at present? Have you made any changes to your process since it was issued? If so, you have a legal obligation to inform the issuing water authority.

“As well as taking any process changes into account, if you’ve recently increased your workforce, this will directly affect your trade effluent billing. Trade effluent charges are often worked out using a straightforward equation based on employees’ kitchen & toilet waste entitlement. Your trade effluent volume is calculated thus: no. of employees x their entitlement = sewage waste. The remaining figure after taking into account sewage is your assumed trade effluent volume. So, a 20% increase in admin staff could possibly lead to a reduction in your trade effluent charges!”

Continues Phill: “You must also have a consent licence for every discharge point on your premises. Each licence will have different requirements based on what effluent is going through that section of sewer.

CASE STUDY
We work with a national bakery that has three separate consent licences for three different production lines to monitor their trade effluent. Each production line has a different number of employees, all of which is taken into account in the respective licence requirements. If any changes to the production lines are implemented that will affect discharge volumes, the consent licence should be reviewed to ensure continued compliance.

“A consent licence will specify what you should and also what you need to monitor, and the water company will visit your site at a set frequency to take samples. Effective monitoring and data analysis are key to achieving complete compliance and avoiding those costly fines for breach of consent.”

Trade effluent sampling

When it comes to sampling you or the water authority can take a ‘spot sample’ and send it off for analysis and await the results. Spot sampling is fine, but it will only ever provide a concentrated snapshot of the trade effluent based on one sample which could, or could not, be a good thing. Most importantly, you’ll only know if you’ve breached consent when you get the results back and, by then, it could be too late and you could be facing an expensive fine.

Using the ‘average sample’ method is far more intuitive as it gives a much more robust insight into what is happening with your trade effluent over a certain period of time. Average sampling can be delivered in two different ways: time proportional sampling will take samples over a period of 24 hours, for example, and flow proportional sampling will wait until a certain volume has been discharged and then take a sample. Flow proportional sampling is better than time proportional sampling since it’s much more indicative of the overall process.

Adds Phill: “Using an external sensor as a trigger, flow is measured, calculated and analysed and we have a monitor and logger specifically designed to deliver all of this, the MSFM flow meter. It can be set up to trigger an alarm if consent is close to being breached. Alarms can be actioned by you or a member of our datacentre team can alert you to an alarm. They will then inform the relevant individual within your company who can then do something about any issue before it causes a problem.

Most consent licences will require you to monitor flow and very often pH and temperature. Plus, depending on the contents of your trade effluent, other parameters such as turbidity or conductivity. Our ORAKEL System is modular and can accommodate multiple sensors to monitor a wide variety of characteristics and is increasingly being employed by a variety of manufacturing and processing firms to monitor their trade effluent.

CASE STUDY
A paper mill approached us to monitor the flow, pH and temperature of their trade effluent as required in their consent licence. We installed a multi-channel logger and set a number of different alarms. If the mill is close to a breach of consent an alarm is triggered which is received by the operations team who can immediately address the problem.

Concludes Phill: “It really doesn’t matter what industry or sector you are in, if you are producing trade effluent it makes sound commercial sense to monitor it. A consistent and effective monitoring process will not only ensure you are informed and compliant at all stages but could also add to your bottom line.”