Removal technology of volatile organic compounds from biogas slurry and fertilizer efficiency test

Objective To screen out the optimal applicable method to remove volatile organic compounds (VOCs) from biogas slurry.

Method Heat treatment, activated carbon, air treatment and organic solvent extraction were adopted to remove VOCs from biogas slurry.

Result and conclusion Treatment conditions and the removal rates for different treatment methods with the best removal efficiency were as follows: the temperature for the heat treatment was 70℃ and the removal rate of VOCs from biogas slurry was 57.7%; the dosage of activated carbon was 12 g for 200 mL biogas slurry and the removal rate was69.9%; the dosages of sulfuric acid, sodium hydroxide, hydrogen peroxide, were all 20 mL for 200 mL biogas slurry, while the removal rates were 36.4%, 39.2% and 39.3% respectively; the removal rates for the treatments of nitrogen, air and ozone were 53.0%, 67.3% and 81.7% respectively. The removal rate of chloroform + petroleum ether extraction could reach 87.4%. The VOCs removal rate could reach 94.1% by combining VOCs ozone with organic solvent extraction, which was effective without affecting fertilizer efficiency. The combined treatment of ozone and organic solvent extraction is the most effective measure for the deodorization of biogas slurry.