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“The definition of trade effluent is set out in 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' the waste water”


“The Mogden Formula is a complex mathematical formula incorporating several important variables. It is used by UK water companies to calculate the trade effluent charges a business will incur when it disposes of its industrial effluent to a foul sewer. The name of the formula comes from the Mogden Water Works in Isleworth, London. They were the first to develop the formula, and it has since been adopted as the industry standard.”

Expressed as:

Trade Effluent Charge = R + [(V + Bv) or M] + B(Ot/Os) + S(St/Ss)7

R          The charge for receiving the effluent, given per cubic metre.

V          The charge for primary treatment, per cubic metre.

Bv        An additional charge if the wastewater needs to be treated biologically. This doesn’t apply in every case.

M         Extra charges per cubic metre if the water is discharged into the ocean.

B          Charge depending on the biological oxidation of sewage.

Ot/Os   Chemical oxygen demand measurements.

S          Charge for getting rid of primary sewage sludge, in kg.

St/Ss   Measurement of total suspended solids in the effluent, measured per litre.


Image courtesy of Open Channel Flow

The Monitoring Challenge.


Understanding the monitoring requirements of trade effluent variables depends on a company’s manufacturing/processing system on site and the requirements of the individual Water Utilities policy of discharges to open water courses as monitored by the Environment Agency/SEPA.


The monitoring point at final discharge from the site ranges from something as simple as an open channel flow meter through to complex sensor arrays where intricate processes operate with online monitors measuring parameters from pH to mercury; COD/BOD, suspended solids, TOC/TOD, VOC’s including industry specific chemicals.  Critical to all this measurement is the data recovered, how it is used, the reporting and critical alarm states getting information to the right place(s).

Not only are we protecting our delicate biodiversity in our surface water courses, we need to ensure that as a business, the wastewater treatment works maintains its functionality. Lack of care can close a treatment plant down and incur substantial penalties.

Critical to the business is ensuring that the charges levied against them are true and accurate. As such trade effluent is a balancing act with cost versus environmental and engineering impact.


In general terms, trade effluent data is gathered through dataloggers manually, with locally positioned computer or the company intranet on to a specific pc and sometimes server. Lab analysis is often completed on site, commonly resulting in a disconnect or delay between different stakeholders.. Reporting often is manual and submitted not only to the Trade Effluent Officer but also to accounts and to senior management.


The ETEM Solution

The daily barrage of data an organisation produces, finding and using essential information is a challenge. ETEM revolutionises this process. It allows all data to be accessed from a single portal in real-time by the whole organisation and globally.


  • With information and report creation at your fingertips.

  • Data driven decision making that optimise processes.

  • Data driven decisions and process that meet and conform to compliance requirements.

  • No more site visits to ’just check’ or downloading data.

  • Multiple site data monitoring and reporting globally through the single portal.

  • Remote site monitoring to alleviate unnecessary and costly site visits.

  • Fully expandable and customisable, through the software engine eRIS.

  • eLogbooks combine notes and multimedia with real-time data.  

  • A solution that matches all application needs, abilities, and budget.


Annual Data Service contract

Connecting to existing monitoring solutions/stations all data will be monitored every 10 minutes

Uncomplicated scheduling and distribution of data.

From this tabular and graphical data will be available daily from each measurement point

Laboratory data gather from autosampler or manual grab, input direct by the Laboratory/test centre

Mogden formula implemented in a monthly report

Unexpected rate of changed monitored and alarm reported to nominated personnel

Photographic data implemented directly in to eRIS for visual analysis or reporting