Ecological Engineering 60 (2013) 421–427 Contents lists available at ScienceDirect Ecological Engineering journa l h om epage: www.elsevier.com/locate/ecoleng A method for determining the treatment dosage of drinking water treatment residuals for effective phosphorus immobilization in sediments Changhui Wang a , Jincheng Liang a , Yuansheng Pei a,∗ , Laura A. Wendling b,1 a The Key Laboratory of Water and Sediment Sciences, Ministry of Education, School of Environment, Beijing Normal University, Beijing 100875, PR China b CSIRO Land and Water, Centre for Environment and Life Sciences, Private Bag 5, Wembley, WA 6913, Australia a r t i c l e i n f o Article history: Received 15 April 2013 Received in revised form 1 August 2013 Accepted 20 September 2013 Available online 16 October 2013 Keywords: Drinking water treatment residue Sediment Phosphorus Remediation Eutrophication Reuse a b s t r a c t Drinking water treatment residuals (WTRs), non-hazardous by-products generated during treatment of drinking water, can be reused to immobilize phosphorus (P) in sediments for eutrophication control. Prior to application, it is necessary to determine the treatment dosage of WTR to immobilize P in sediments. In the present study, the dosage of Al/Fe based WTRs required to effectively immobilize P in lake sediments was determined in a laboratory setting as a function of the oxalate-extractable Al (Al ox ) and Fe (Fe ox ) content of the WTRs by completely mixing Al/Fe based WTRs with Lake Baiyangdian sediments. The results showed that the capacity for immobilization of mobile P (P m ) in sediments by Al ox and Fe ox in Al/Fe based WTRs ((Al ox + Fe ox ) WTR ) can be described by the equation: (Al ox + Fe ox ) WTR = 83*P m –40 (where Al ox , Fe ox and P m are expressed in mol g -1 ). This equation was successfully used to determine the respective quantities of three different Al/Fe based WTRs required to immobilize P in sediments from Lake Chaohu, Lake Taihu, the Changjiang River, the Haihe River, the Pear River and the Yellow River. Using the equation derived herein, the required Al/Fe based WTR application dose can easily be determined where the P m content of the sediment and the Al ox and Fe ox content of the WTR are known. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Excessive phosphorus (P) in water bodies (e.g. lakes, rivers, etc.) can lead to eutrophication, and internal loading from P-enriched sediments is one of the primary origins of excessive P (Haggard and Soerens, 2006; Cyr et al., 2009; Jin et al., 2013). At present, in situ P immobilization is a comparatively new technology for remediating P-enriched sediments (Paller and Knox, 2010). In situ P immobilization utilizes chemically reactive materials to sequester P in non-labile forms within sediments, thereby reducing internal Abbreviations: Alox, oxalate-extractable Al; BD-P, Na2S2O4/NaHCO3 extractable P; BJ1-WTR and BJ2-WTR, WTR from Beijing City No. 9 Waterworks; Feox, oxalate- extractable Fe; HCl-P, HCl extractable P; HZ-WTR, WTR from Hanzhou City Tap Water Plant; ICP-AES, inductively coupled plasma atomic emission spectroscopy; Lake B, Lake Baiyangdian; Lake C, Lake Chaohu; Lake T, Lake Taihu; NaOH-P, NaOH extractable P; NH4Cl-P, NH4Cl extractable P; P, phosphorus; Pm, mobile P; River C, Changjiang River; River H, Haihe River; River P, Pear River; River Y, Yellow River; TP, total P; WTRs, drinking water treatment residuals. ∗ Corresponding author. Tel.: +86 10 5880 1830; fax: +86 10 5880 1830. E-mail address: yspei@bnu.edu.cn (Y. Pei). 1 Present address: The University of Queensland, School of Agriculture and Food Sciences, St Lucia, QLD 4072, Australia. P loading in water bodies (Yuan et al., 2009; Egemose et al., 2010). The selection of materials with high P sorption capacity and low environmental toxicity is critical to the successful application of in situ P immobilization technology (Paller and Knox, 2010). Mate- rials such as Fe and Al salts are often used due to their high P immobilization capacities (Hansen et al., 2003; Reitzel et al., 2005, 2006). Despite their effectiveness, a low-cost alternative to Fe and Al salts is sought to overcome financial constraints to widespread use, particularly where the application of a large quantity of P immobilizing material is required. Drinking water treatment residuals (WTRs) are ubiquitous, non- hazardous by-products generated by drinking water treatment plants (Babatunde and Zhao, 2007; Ippolito et al., 2011). They are primarily comprised of Fe/Al hydroxides because Fe and Al salts are routinely used to remove suspended solids and humic substances from raw water. The Fe and Al in WTRs are primarily amorphous and exhibit high P adsorption capacity (Li et al., 2013). It has been demonstrated that WTRs can be used as soil amendments to miti- gate off-site P pollution (Agyin-Birikorang et al., 2009) or as media for constructed wetlands to remove excessive P in wastewater (Park, 2009; Zhao et al., 2009). Nevertheless, WTRs are generally regarded as waste materials (Babatunde and Zhao, 2007). There- fore, the development of novel productive uses for WTRs is of 0925-8574/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ecoleng.2013.09.045