Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman Research article Greenhouse tomato plant roots/carboxymethyl cellulose method for the efficient removal and recovery of inorganic phosphate from agricultural wastewater David Ure a , Angela Awada a , Nicole Frowley a , Neils Munk b , Amanda Stanger b , Bulent Mutus a,∗ a Department of Chemistry and Biochemistry, University of Windsor, Ontario, Canada b Bruce Peninsula Biosphere Association (BPBA), Tobermory, Ontario, Canada ARTICLE INFO Keywords: Phosphate remediation Phosphate recovery Carboxymethyl cellulose Calcium-phosphate Tomato plant roots Agricultural wastewater ABSTRACT Phosphate (P) is a biologically important compound that is commonly incorporated into fertilizers. Wastewater from agricultural processes results in excessive accumulation of P and eutrophication of lakes. We have devel- oped a system for the remediation, recovery, and potential reuse of P from agricultural wastewater using tomato plant roots (roots) as a capture matrix and carboxymethyl cellulose (CMC) as an eluent and enhancer of P precipitation. Untreated roots can bind up to 55.2 ± 15.2 grams of P per kilogram (g/kg) of roots in comparison to the maximum 8.2 ± 1.5 g/kg bound by the previously used iron-chitosan (Fe-chito). The addition of CMC enhances the precipitation of P with a clearance of 97.2% as opposed to 33.3% without CMC. On site tests show an average removal of 226.5 μg/L per day or a total of ∼28 g of P removed after 23 days. This corresponds to a 71% P removal rate. 1. Introduction Fertilizers rich in the macronutrients phosphorous, nitrogen, and potassium are used world wide to increase crop yields. Contemporary fertilizers use inorganic P sourced from phosphate rock. Concerns have arisen regarding the dependence on this non-renewable resource and its dwindling supply (Abelson, 1999; Cordell et al., 2009). Anthropogenic nutrient loading from crop and livestock farming leads to the accu- mulation of nutrients such as P and nitrate in lakes leading to eu- trophication. This results in the rapid growth of algae which can form harmful algal blooms that endanger aquatic ecosystems and human health. (Schindler, 1977; Downing and McCauley, 1992; Abelson, 1999; Anderson et al., 2002; Ho and Michalak, 2015; Maguire et al., 2018). For example, in 2014 an algal bloom in Lake Erie forced the city of Toledo, Ohio to shut down tap water for three days (Wilson, 2014). These negative economic and environmental impacts incentivize the reduction of anthropogenic nutrient loading. A long term study has shown that mitigation of nutrient input is effective at reducing algal biomass and returning lake systems to a healthy state (Riemann et al., 2015). Application of manure to fields as a fertilizer has been used since the agricultural revolution to enhance crop yield (Cordell et al., 2009). Direct application leads to leeching of nutrients into nearby lakes. Treatment of manure using anaerobic digestion can reduce nutrient leeching (Macias-Corral et al., 2008). Alternatively, the use of manure in energy producing processes such as superheated steam drying re- duces nutrient loading (Hanifzadeh et al., 2017). Reducing nutrient inputs from agricultural sources produces desir- able environmental outcomes. However, large capital costs and minimal long-term economic benefits make large scale implementation difficult. Low cost filtration of nutrients from wastewater is one option but still typically suffers from operating costs that exceed potential gains (Zhang, 2014; Mayer et al., 2016). The combination of an in- expensive filtration matrix and cost-effective nutrient recovery method will increase the financial viability of a filtration operation. The objective of this study was to use locally available cellulose- based biopolymers to create a low-cost P filtration matrix. While doing so, we found a method that may reduce the costs associated with P recovery. Our previous matrix was the biopolymer chitosan functio- nalized with iron to produce an iron-chitosan composite (Yep, 2016) which was effective at P remediation but poor lifespan and rising chitosan cost led to the search for a new P-binding matrix. To this end, multiple cellulosic materials were investigated including sawdust, roots, and coconut husk. Of these tomato plant roots showed the largest P-remediation potential. Our lab is located near Leamington, Ontario one of the largest tomato producing regions in North America. https://doi.org/10.1016/j.jenvman.2018.12.053 Received 29 September 2018; Received in revised form 28 November 2018; Accepted 17 December 2018 ∗ Corresponding author. Department of Chemistry and Biochemistry, University of Windsor, Ontario, N9B 3P4 Canada. E-mail address: mutusb@uwindsor.ca (B. Mutus). Journal of Environmental Management 233 (2019) 258–263 0301-4797/ © 2018 Elsevier Ltd. All rights reserved. T