The ability of biochars from cookstoves to remove pharmaceuticals and personal care products from hospital wastewater

Adequate treatment of wastewater to remove micropollutants constitutes a major concern globally. Despite this, large volumes of untreated wastewater are released into the environment, mainly due to the cost involved. Biochars have been suggested to have the potential to remove pharmaceuticals and personal care products (PPCP) from wastewater, but, adsorption potential needs to be investigated further. Production of biochars should also preferably be sustainable and based on low-cost materials. This study investigated the ability of nine biochars produced in three cookstoves and from three feedstocks. All biochars were characterized and then applied in adsorption experiments, based on authentic hospital effluent. Our analytical method included 32 pharmaceuticals and personal care products, and 28 of these were detected and quantified in hospital wastewater effluent samples. Some PPCP were present in relatively high concentrations (more than 24 µg/L). Adsorption experiments showed that the biochars used in the investigation had average removal rates (RR) ranging from 14.2% to 65.5%. Removal rates also varied between and within cookstoves and feedstock. Although cookstove biochars with a low surface area in this study generally showed lower removal rates, results from surface characterization were not detailed enough to correlate the physicochemical properties of the pollutants with the adsorption. Further characterizations are therefore needed to point out the most important parameters involved in PPCP adsorption on cookstove biochars.