Enirgi Power Storage (EPS) is Australia’s largest recycler of used lead–acid batteries. The company has two battery-recycling facilities, namely, a 70 000 tonne plant at Wagga Wagga that is Australia’s largest plant, and a 30 000 tonne plant in Sydney. The former plant operates as a closed-loop, zero discharge effluent site. The Engitec desulfurisation process is employed together with an in-house method for effluent treatment. The chemical treatment of collected process effluent and stormwater was deemed ineffective to meet strict EPA discharge limits, thus an alternative was required. A series of filtration stages that end in a nano filtration unit has been adopted to achieve the required target for treated water quality. Nano filtration, also known as reverse osmosis, functions by sending pressurized effluent over a membrane that has pores of a selected size. The pressure forces all particles that are smaller than the pore through the membrane so that larger particles remain in the resultant stream of effluent waste.