EFFECTS OF MEMBRANE CONCENTRATION PROCESSES ON FLUX, NUTRIENT RECOVERY, AND ANTIBIOTIC ISOLATION FOR ANAEROBICALLY DIGESTED SLURRY FROM SWINE MANURE

Membrane concentration processes have been used to treat anaerobically digested (AD) slurry for nutrient recovery and pollutant removal; however, these methods often face the challenges of low processing stability and efficiency. In this study, the performance (processing stability and efficiency) of three membrane concentration processes, including nanofiltration (NF), reverse osmosis (RO1) and two-stage NF-RO (NF-RO2), in treating ceramic membrane-pretreated swine manure AD slurry was evaluated and compared. Nutrient and antibiotic redistribution in the concentrate and permeate was also investigated. Results show that NF-RO2 had higher processing stability and efficiency than the other two processes. High nutrient recoveries of 61.9% for total nitrogen, 56.3% for total phosphorus, and 67.0% for potassium in the concentrates were observed in NF-RO2. The removal rates for antibiotics sulfamethazine and oxytetracycline in NF-RO2 were 99.3% and 81.9%, respectively. Therefore, NF-RO is an effective way to recover nutrients and remove pollutants from AD slurry.