Comparing the effluent organic matter removal of direct NF and powdered activated carbon/NF as high quality pretreatment options for artificial groundwater recharge.

Direct nanofiltration and nanofiltration combined with powdered activated carbon known as the PAC/NF process were tested regarding the removal of effluent organic matter for reclamation of tertiary effluent from a municipal wastewater treatment plant. They can be regarded as a promising treatment alternative for high quality water reuse applications, especially for direct injection. The total removal for DOC was above 90% with permeate concentrations below 0.5 mg/l. Size exclusion chromatography and fluorescence EEM proved to trace origin of the organic matter even in low concentration ranges. The type and dosage of adsorbent influences the process performance significantly and allows process optimization.