Environmental guidance for your business in Northern Ireland & Scotland

How to deal with Trade Effluent

How to deal with Trade Effluent

If your business produces trade effluent there are a number of ways that this can be managed.

  • If possible you should connect to a public sewer. This is the best option for treatment and disposal of trade effluent. If no public sewer is available you should look at connecting to the public sewer using a private sewer. You will still need a trade effluent consent or trade effluent agreement with your sewerage provider. Read the page in this guideline: Disposal to public sewer


  • Effluent that your sewerage provider will not accept. If you produce trade effluent that will damage the sewer, or would create risks for workers or the public you will not be able to discharge it to a public sewer. Read the page in the is Guideline: Dealing with effluent that can't go to foul sewers


  • Discharge to land. If no public sewer is available you must look at ways of treating your trade effluent before discharging it to land via a soakaway. Discharging treated effluent to land provides an extra level of treatment and is a better option than discharge to water. You will need an authorisation from the NIEA or SEPA before you can discharge your trade effluent to land. You will have to achieve a suitable level of treatment before any discharge will be permitted. Read the page in this guideline: Disposal to land where no public sewer is available.


  • Discharge to water. If a connection to a public sewer is not possible and there is not sufficient or suitable land for a soakaway, you may be able to discharge treated effluent directly to surface waters. If land is available for a reed bed or a gravel filter bed, then this can provide extra treatment to the effluent before final discharge. You must speak to the NIEA or SEPA to find out if this is suitable. Read the page in this guideline: Disposal to water, where no public sewer is available.


  • Treating your trade effluent. If you need to treat effluent before discharging it, you can use package treatment plants or septic tanks. Package treatment plants are generally more effective than septic tanks and achieve a higher quality of treatment. Where possible this should be connected to a soakaway, rather than directly to a watercourse. Read the page in this guideline: Using septic tanks and package treatment plants.


  • Improving the quantity and strength (concentration of substances) of your trade effluent. If you discharge to a public sewer the cost of sewerage services will depend on the volume of trade effluent you produce and what substances your trade effluent contains. You can reduce your costs by reducing the quantity of trade effluent you produce and by looking at ways of reducing the substances that enter the effluent. You could also consider treating it before it goes to sewer. If you cannot discharge to a public sewer and you want to discharge to land or to water, you can reduce the quantity or the strength of the effluent. This will make it easier to obtain the correct authorisation from the NIEA or SEPA. Read the page in this guideline: Reducing and treating your trade effluent

Back to Trade effluent home page

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