Wastewater at mineral sites

Wastewater treatment at mineral sites

Your business can generate wastewater through a range of operations including:

cleaning
flushing from manufacturing processes
acid polishing, polishing or etching that creates acid rinse water
cooling rock cutting equipment and transporting fines
quenching and cooling operations.

Wastewater can contain high proportions of suspended solids or other contaminants. Your business activities will determine the nature of these contaminants. For example:

ceramics wastewater may contain clay particles, glaze and dissolved substances such as sulphates or heavy metals
wastewater from areas where there is spilled batch material from glass production may contain metals or metal compounds
wastewater from rock cutting will contain high levels of fine particles
water from cleaning and washing out concrete mixers will be highly alkaline and will contain solids.

What you must do

Establish exactly what is in the wastewater that your operations produce. You may need to have laboratory tests carried out on samples of your water.

Decide whether you can reuse the wastewater within your process and if so, whether you have to treat it before you can reuse it. For example:

you will have to neutralise acid rinse water periodically
water you use for washing out concrete mixers will be highly alkaline and you may have to neutralise it before you reuse it
you may need to pass any wastewater that contains suspended solids through a settlement tank or dose it with flocculent before you can reuse it.

To reuse wastewater or to treat wastewater you may need a waste management licence or to register an exemption.

An exemption allows you to recover or dispose of waste at the place where it is produced. This is only if the waste was generated from an integral part of the production process.

You will usually need to register an exemption with your environmental regulator for these activities.

You must still ensure that your activity does not:

endanger human health or cause pollution to water, air or soil
cause a risk to plants or animals
cause a nuisance in terms of noise, dust, fumes, smoke or odour
adversely affect the countryside or places of special interest.

Waste management licences

You cannot dispose of liquid wastes in landfill.

If you cannot reuse your wastewater as part of your process, you may need to treat it to remove any contaminants before you dispose of it.

You could treat wastewater at your premises or this could be carried out off-site by a contractor. If your wastewater leaves your site for treatment elsewhere, the duty of care will apply to it.

Duty of care - your waste responsibilities

If you decide to treat wastewater on your premises, you will need to employ a specialist to design, install and commission a suitable treatment process. The treatment process should ensure that the quality of the wastewater after treatment will allow you to discharge it to:

the foul sewer, subject to a consent from your water and sewerage company or authority
surface or groundwater, subject to permission from your environmental regulator.

If you allow wastewater to enter the ground, watercourses, surface water drains or foul water sewers without permission, you may be committing an offence.

Preventing water pollution

Discharges to water and sewer