Biologically enhanced granulated activated carbon (BAC) filtration of a mixed industrial/domestic tertiary effluent for reuse
Biologically enhanced granular activated carbon (BAC) is a promising wastewater post-treatment to produce a purified effluent suitable for recycle in the textile industry. Three small pilot scale filters were used, filled with three media (two adsorbent media and one non-adsorbent), to compare two different GACs and quantify the biomass contribution to organic removal and colour abatement. A demonstrative scale filter was tested in parallel to evaluate the influence of hydraulic parameters on BAC process efficiency. Biomass contribution was significant when an acclimated biofilm grew on particles; in all cases, wastewater decolorising was due to physical-chemical adsorption only; higher hydraulic load negatively affected the polishing process. Laboratory and semi-industrial scale tests were performed on textile fibres and fabrics using samples of the effluent from the demonstrative filter. The tests confirmed the suitability of the treated water for textile reuse.