Laboratory investigation of phosphorus immobilization in lake sediments using water treatment residuals

This work investigated the potential for reusing water treatment residuals (WTRs) to immobilize phosphorus (P) in the sediments of Lake Taihu and Lake Baiyangdian. The results indicated that WTRs made inorganic P more stable in the sediments, although the sediments from each lake had dissimilar properties. Conversely, WTRs had no effect on the activity of organic P. However, after the sediment was mixed with WTRs, the inorganic P was immobilized in 10 days. Microbiological analyses further revealed that WTRs could alter the structures of the microbial community within the sediments but exert no adverse effect on the bacterial diversity. Moreover, WTRs were found to be beneficial to microorganism growth. Because of the effects exerted by WTRs, the total abundance of bacteria in the sediments increased from 5.10 × 1012 to (0.66–4.81) × 1014 copies g−1 for Lake Baiyangdian sediments and from 1.16 × 1013 to (1.08–7.14) × 1014 for Lake Taihu sediments. Therefore, WTRs can be safely used to immobilize P in sediments for the purpose of lake restoration.

► Water treatment residuals (WTRs) can immobilize inorganic P in lake sediments. ► WTRs presented little effect on the activity of organic P in lake sediments. ► WTRs are not detrimental to microorganisms.