Evaluation of COD and turbidity removal from compost leachate wastewater using Salvia hispanica as a natural coagulant

Abstract

Landfill leachate, as one of the organic pollutants, generates various dangers for groundwater and soil. Due to the reduction of water resources in the world, treatment of this contamination from water is very essential. In this study, mucilaginous extract of Salvia hispanica (Chia) was used as an active natural coagulant for leachate treatment. Leachate samples were collected at a chemical oxygen demand (COD) of 63,500 mg/L and a turbidity of 670 NTU. Optimization of the coagulation-flocculation (CF) process was investigated by response surface methodology (RSM) based on a central composite design (CCD). A quadratic polynomial model was fit with the data at a R2 of 0.97 for COD reduction and a R2 of 0.99 for turbidity removal, respectively. The effect of three parameters, including contact time, pH, and natural coagulant dosage on the COD reduction and turbidity removal were evaluated. The COD reduction and turbidity removal were obtained 39.76% and 62.4% in optimal condition, after 45 mines using 40 g/L of Salvia hispanica at pH 7. To the best of our knowledge, this is the first report on the use of Salvia hispanica as a natural coagulant for leachate treatment.