Trade wastewater is any wastewater produced by a commercial or industrial activity.

It doesn't include sewerage from toilets or sinks, but does include the run-off from industrial sprays and cooling systems.

Wastewater isn't always toxic, but even non-toxic wastewater can be harmful if it's put straight into the sewer without the problem substances being removed first.

Before you let wastewater go into the sewerage system, you need to remove the contaminants, and your company needs to get a wastewater permit from the local water authority.

This permit will specify the treatment process required and any other standards that may apply.

But not all businesses need to put their wastewater into the sewerage system.

Some companies recycle the wastewater on-site, and treat it so it can be used in other production processes or for watering the garden.

Other companies collect the wastewater in drums, and have it taken to a waste disposal station. But remember that if you're sending it to a waste facility, the transportation must always be done by a licensed contractor.