Concentrating process of liquid digestate by disk tube-reverse osmosis system

• Published in: Desalination 2013-10, Vol.326, p.30-36
• Main Authors: Gong, H., Yan, Z., Liang, K.Q., Jin, Z.Y., Wang, K.J.
• Format: Article
• Language: English
• Subjects: agricultural industry; amino acids; Applied sciences; Biogas; Chemical engineering; Concentrating process; desalination; Disk tube-reverse osmosis; Disks; Exact sciences and technology; Farms; Fouling; Liquid digestate; Liquids; Membrane fouling; Membrane separation (reverse osmosis, dialysis...); Membranes; nitrogen content; Nutrient recovery; nutrients; Osmosis; phosphorus; Plants (organisms); Pollution; poultry; transportation
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2013.07.010

The utilization of liquid digestates from centralized biogas plants commonly used in the agricultural sector of China is limited by the high transportation and storage costs resulting from their extremely large volumes. A pilot-scale disk tube-reverse osmosis (DT-RO) system was set up in the biogas plant of a poultry farm to test the efficiency of the concentrating process. This set up was operated for 1year to optimize the system and evaluate membrane fouling. The liquid digestate volume remarkably decreased by about 25%, with a concentration factor of 4 under an operation pressure of 45bar to 55bar. Nutrients and mineral elements were simultaneously accumulated and total nitrogen and total phosphorus increased by 4.2 and 4.4 times, respectively. The total amino acid in the concentrated digestate reached 4.93g/L. SEM–EDS analysis showed that membrane fouling was an integrated result of inorganic and organic fouling. •Disk tube reverse osmosis to concentrate liquid digestate•Concentrating process of liquid digestate for eco-agriculture utilization•High concentrating performance in COD, TN, TP and amino acid•Controlled membrane fouling in pilot scale experiment