The influence of alum based nutrient removal process on the physical, chemical and biological characteristics of phosphorus in the paper processing facility effluent.

This study examined the physical, chemical and biological characteristics of the phosphorus (P) in the effluents from a paper processing facility before and after an alum based P removal process. The alum based treatment process reduced effluent total P concentrations from an average of 230 ± 103 (±1 SD) μg L−1 to an average of 36 ± 10 μg L−1. Ultra-filtration showed the treatment process shifted the P in these effluents from being 75 ± 9% particulate pre-removal to being 52 ± 0% dissolved and 27 ± 1% colloidal after the Trident P removal process. The alum removal process also reduced the fraction of reactive P in the dissolved and colloidal pools from 55% to 14%, respectively. Algal phosphorus bioavailability (BAP) bioassays showed the BAP of these effluents averaged 12 ± 9% of total P. Algal dissolved P uptake experiments indicated ≈ 30% of the dissolved P was converted to particulate P (which usually indicates algal uptake) during 21-day bioassays. However, treatments without algae indicated >80% of the apparent algal uptake may have been due to colloidal P forming flocs via physical-chemical processes. These analyses indicate the phosphorus contained in this paper processing facility's effluents had much lower bioavailability than the P in typical municipal wastewater treatment plant effluents. Unlabelled Image • Alum based technology was effective in treating paper processing facility effluent. • P in the effluent from paper processing facility had very low bioavailability. • Most of the P in the paper mill effluents tested was humic bound. • P uptake in bioassay experiment was mainly due to physical-chemical processes. [ABSTRACT FROM AUTHOR]