Hydrogel chitosan sorbent application for nutrient removal from soilless plant cultivation wastewater

In this study, we determined the effectiveness of removal of nutrients (nitrates and orthophosphates) from greenhouse wastewaters (GW) using non-cross-linked chitosan (CHs) and chitosan cross-linked with epichlorohydrin (CHs-ECH) in the form of hydrogel beads. GW used in the study had the following parameters: N-NO₃ 621.1 mg/L, P-PO₄ 60.8 mg/L, SO₄^2- 605.0 mg/L, Cl^- 0.9 mg/L, Ca²⁺ 545.0 mg/L, Mg²⁺ 178.0 mg/L, K⁺ 482.0 mg/L, hardness 113° dH, and pH 6.2. The scope of the study included determination of the effect of pH on wastewater composition and effectiveness of nutrient sorption, analyses of nutrient sorption kinetics, and analyses of the effect of sorbent dose on percentage removal of nutrients from GW. CHs-ECH was able to sorb 79.4% of P-PO₄ and 76.7% of N-NO₃ from GW, whereas CHs to remove 92.8% of P-PO₄ and 53.2% of N-NO₃.