Adsorptive removal of phosphate from aqueous media by peat

The identification of effective filtering materials is imperative for cleaning wastewater before its discharge. Laboratory-scale batch experiments and column leaching were conducted to evaluate the effectiveness of peat in removing phosphate (P) from wastewater. Major factors involved, including the initial P and adsorbent concentrations, adsorption kinetics, temperature, and pH were also investigated. Peat was effective in P removal from wastewater, especially at its low P concentrations (1–2 mg/L). The maximum P adsorption on peat was 8.91 mg/g and the P adsorption followed the Langmuir and Freundlich model. The adsorption on peat decreased with increasing temperature and was the highest at pH 6.5. Generally, P removal increased with increasing adsorbent dose rate. Column flow-through tests using a secondary effluent confirmed the results obtained from batch experiment. The removal rates of dissolved phosphate (DP) and total phosphate (TP) by a peat column from the secondary effluent were 94–99% and 76–95%, respectively. These results suggested that based on large surface area and high amorphous Fe and Al contents, peat possessed great potential for its use as substrate bed material for adsorptive P removal from secondary wastewaters.