ERWAT is currently custodian of 19 wastewater treatment works (WWTW), treating a combined capacity of between 700 megalitres and 1000 megalitres (million litres) of wastewater per day (Mℓ/d) depending on the season.

Activated sludge processes, designed for biological nutrient removal or biological filtration processes and combinations thereof are generally employed in the purification of the wastewater. The designed capacity of the individual works, based on the average dry weather flow rate, varies from 0,4 Mℓ/d to as high as 170 Mℓ/d.

ERWAT follows a business-orientated approach towards wastewater management. The company offers client needs-based solutions, from operational, technical to management aspects.