A model for predicting reduction in mobile phosphorus of lake sediment by aluminum drinking water treatment residuals

• Published in: Water research (Oxford) Vol. 232; p. 119677
• Main Authors: Kuster, Anthony C., Huser, Brian J., Thongdamrongtham, Somjate, Patra, Santanu, Padungthon, Surapol, Kuster, Anootnara T.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2023
• Subjects: Algae; Alum sludge; Aluminum; Cyanobacteria; Drinking Water; Eutrophication; Geologic Sediments; Lakes; Langmuir isotherm; Phosphorus; Vattenbehandling; Water Pollutants, Chemical - analysis; Water Purification; Water quality; Water Treatment; Alum sludge; Algae; Langmuir isotherm; Cyanobacteria; Water quality; Eutrophication
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2023.119677

•Drinking water treatment residual (DWTR) inactivated phosphorus (P) in lake sediment.•An empirical model was developed to describe P inactivation by DWTR.•Model inputs were initial mobile P in sediment and oxalate-extractible aluminum in DWTR.•The model was able to successfully predict sediment mobile P following DWTR dose.•The model can be used to determine DWTR dose for lake restoration.
Drinking water treatment residual (DWTR) derived from flocculation and sedimentation of raw water using aluminum coagulants is a valuable environmental remediation byproduct capable of inactivating phosphorus (P). However, no generalizable model exists in the literature to describe reduction of releasable (mobile) P in lake sediment as a result of DWTR addition. The reduction of mobile P (sum of labile P and reductant soluble P) was investigated in over 100 sub-samples using five sediment samples from two lakes and three DWTRs from different water treatment plants. A consistent relationship was determined across a range of mobile P contents (0.23 g/m2/cm to 0.92 g/m2/cm, or 15.8 to 186.1 µg/g DW) and DWTRs. The relationship was best described as a function of the mobile P content of the sediment and the oxalate-extractable aluminum content of the DWTR. An empirical model was developed to predict the immediate reduction in mobile P following the addition of DWTR containing aluminum. This model was validated using two additional lake sediments and one additional DWTR (R² = 0.995). Thus, the immediate inactivation of P in lake sediment following DWTR addition can be predicted with this model, which can be used with internal P loading or other water quality goals to determine an appropriate DWTR dose. Further recommendations were made about dosing DWTRs for lake restoration, allowing practitioners to use DWTR to inactivate P in lake sediment without conducting individual sorption experiments.
[Display omitted]