Wastewater Costs

Mogden Formula

If industrial wastewater is sent to foul sewer there will be a "Trade Effluent Charge". This is calculated and collected by the receiving Water Company to recover the cost of carriage to and treatment in their treatment plants (sewage works). The scale of this charge depends on set factors, coupled with the measured "strength" and quantity of the received effluent.

If you are responsible for or have an interest in the treatment costs of effluent discharge, Oasis have a Free Excel spreadsheet by clicking here.

This useful tool calculates the expected cost of effluent and easily shows how on-site treatment can reduce and control costs.

More about the Mogden Formula

The Mogden Formula is Stated as:

C = R + V + Vb + B x Ot/Os + S x St/Ss


C = Total charge rate for disposal (pence/cubic metre)
R = Unit cost for conveyance (pence/cubic metre)
V = Unit cost for volumetric treatment (pence/cubic metre)
Vb = Additional volume charge if there is no biological treatment
B = Unit cost for biological treatment (pence/cubic metre)
Ot = COD of trade effluent (mg/l); Os = COD settled sewage (mg/l)
S = Unit cost for sludge disposal (pence/cubic metre)

St = Solids value trade effluent (mg/l); Ss = Solids value* settled sewage (mg/l)

Understanding the Mogden Formula

Wastewater costs vary depending on the receiving company's charge factors and the following:

In other words, reduction in any or all of the above three variables leads to reduced charges and more control of site costs given that the Water Companies Generate Revenue by Accepting and Treating Wastewater.

Now it can be seen how the quarterly or annual bill is calculated. With the help of the Mogden Calculator this cost can be predicted and show how on-site treatment can reduce this cost.

Contact Oasis Environmental Ltd for informal advice about your requirements. We have the skills and experience to reduce costs and meet other consents which may be set e.g. metals, phosphates, ammonia, and colour removal.

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