ORGANIC POLLUTANTS IN BIOGAS PLANT DIGESTATES - ENVIRONMENTAL BURDEN AND RISK TO FOOD SAFETY

Biogas technology is a sustainable method for managing biodegradable material and for energy production. Sludge from waste water treatment plant (WWTP), sorted municipal biowaste, industrial by-products or animal manure can be used as raw material in biogas plants (BGP). Biogas plant digestates can be used in agriculture as fertilizers or soil improvers. If the raw material for a biogas plant contains organic pollutants, they may end up in the digestate, and finally in agricultural soil. Some of the organic pollutants may have the potential to accumulate in the food chain.

We measured concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDD/F), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), polyaromatic hydrocarbons (PAH), bis(2-ethylhexyl) phthalate (DEHP), perfluorinated alkyl substances (PFAS), linear alkylbenzene sulfonates (LAS), nonylphenols and nonylphenol ethoxylates (NP+NPEO), hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) in digestates from eight biogas plants. Burden of these pollutants into soil after a single addition of digestate was estimated.