Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman Research article Immobilization possibility of tannery wastewater contaminants in the tiles fixing mortars for eco-friendly land disposal M. Aminul Haque a,* , Rakib Ahmed Chowdhury b , Wafa Arbab Chowdhury a , Ashraful Hasan Baralaskar a , Shuvo Bhowmik a , Shriful Islam b a Department of Civil Engineering, Leading University, Kamal Bazar, Sylhet, 3112, Bangladesh b Department of Civil and Environmental Engineering, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh ARTICLE INFO Keywords: Tannery wastewater Encapsulation Contaminant migration Water quality parameters Tiles wall ABSTRACT The Hazaribagh tannery area of Bangladesh is currently facing an enormous problem regarding the harmful impacts of wastewater produced from leather industries on the surrounding environment due to the presence of contaminants at a toxic level. As such, the current study aims to analyze the entrapment of tannery wastewater's pollutants inside the mortar specimens for sustainability. Two types of binding agents such as Portland Composite Cement (PCC) and Ready Mixed Dry Mortar (RMDM) were employed to prepare separate mortar pastes in which the collected tannery wastewater was used as mixing liquid. Also, five types of samples including brick walls made with only the PCC, where tiles walls and blocks constructed with both types of binding agents were built. Analytical results show that the surrogate contaminated water mixed mortar blocks possessed about 6–14% lower compressive strength than that of the blocks prepared with drinking water. Moreover, the ex- amined heavy metals were observed below the limit of detection in the curing liquid of studied tiles walls during the whole test protocol of 360 days period. The explicit outcomes of this study might be a promising solution to minimize the effects of tannery wastewater contaminants on the environment by utilizing this wastewater as a mixing component in the tiles fixing mortar of walls and floors. 1. Introduction 1.1. Environmental impacts of tannery wastewater disposal Tannery effluents are ranked as the highest pollutant among the industrial communities around the world (Tinni et al., 2014; Azom et al., 2012). In Bangladesh, tannery industries have been playing an important role in national economic growth as it accounts for about 4.2% considering the country's total export in 2013–14 fiscal (Juel et al., 2016). Yet, it poses a higher threat to surrounding environment as it generates a huge amount of toxic elements bearing liquid effluent and solid wastes which are generally discharged in open landfill sites especially in the developing countries like Bangladesh (Tinni et al., 2014; Azom et al., 2012). It should be noted that, processing one metric ton raw materials in a tannery industry produces 45–50 m 3 of waste- water that contains 2500–12500 mg/l suspended solids (Juel et al., 2016; Huffer and Taeger, 2004). In leather factories, a large amount of water and chemicals such as basic chromium sulfate, ammonium sul- fides, ammonium chlorides, bactericides, sodium sulfite etc. Are needed to process the untreated materials (Shegani, 2014; Azom et al., 2012). According to Shegani (2014), only 20% of these chemicals are used in manufacturing leathers, and the rest are retained in process water. More importantly, it can be mentioned by the fact that discharging untreated tannery wastewater (TWW) represents a significant source of metals released into the environment (Rizo et al., 2012; Bretzel and Calderisi, 2011; Iwegbue et al., 2010; Waheed et al., 2010; Yarlagadda et al., 1995). In accordance with the several studies (Juel et al., 2016; Jahan et al., 2014; Islam et al., 2013), poisonous matters including arsenic (As), lead (Pb), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), nickel (Ni) and cadmium (Cd) are existing in TWW having a con- centration of 0.026 mg/l, 0.1818 mg/l, 10.348 mg/l, 1.632 mg/l, 0.196 mg/l, 1.524 mg/l, 0.013 mg/l and 0.013 mg/l, respectively. As a result, when TWW are discharged in open fields or canals, it may cause groundwater contamination as there is a high possibility of the waste- water to be seeped through the soil (Jahan et al., 2014). Moreover, due to the migration of toxic wastewater, nearby natural soils have been contaminated with available heavy metals (Chin et al., 2016) that leads to serious problems as they are not biodegradable (Hong et al., 2002). https://doi.org/10.1016/j.jenvman.2019.04.069 Received 22 October 2018; Received in revised form 14 April 2019; Accepted 18 April 2019 * Corresponding author. E-mail addresses: mahaque@lus.ac.bd (M.A. Haque), cn.rakib@yahoo.com (R.A. Chowdhury), wafz.arbab@gmail.com (W.A. Chowdhury), ahbcivilengg@gmail.com (A.H. Baralaskar), theshuvobhowmik@gmail.com (S. Bhowmik), sharif_sust_cee@yahoo.com (S. Islam). Journal of Environmental Management 242 (2019) 298–308 0301-4797/ © 2019 Elsevier Ltd. All rights reserved. T