Two-stage anaerobic membrane bioreactor for co-treatment of food waste and kitchen wastewater for biogas production and nutrients recovery

Chemosphere 309 (2022) 136537

Authors: Thanh-Son Le a,b , Phuoc-Dan Nguyen b,c,* , Huu Hao Ngo d , Xuan-Thanh Bui b,e,**, Bao-Trong Dang b,f , Ludo Diels g , Hong-Ha Bui h , Minh-Trung Nguyen c, Do-Thanh Le Quang c

a Institute for Environment and Resources, 142 To Hien Thanh Street, District 10, Ho Chi Minh City, 700000, Viet Nam

b Vietnam National University Ho Chi Minh (VNU-HCM), Linh Trung Ward, Ho Chi Minh City, 700000, Viet Nam

c Centre Asiatique de Recherche sur L’Eau (CARE) & Faculty of Civil Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Viet Nam

d School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NWS, 2007, Australia

e Key Laboratory of Advanced Waste Treatment Technology, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Viet Nam

f Faculty of Chemical Engineering, Ho Chi Minh City University of Technology (HCMUT), 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City, Viet Nam

g University of Antwerp, Groenenborgerlaan 171 2020 Antwerpen, Belgium

h Institute for Tropical Technology and Environmental Protection (VITTEP), Ho Chi Minh City, Viet Nam

Accepted 16 September 2022

Available online 20 September 2022

Abstract. Co-digestion of organic waste and wastewater is receiving increased attention as a plausible waste management approach toward energy recovery. However, traditional anaerobic processes for co-digestion are particularly susceptible to severe organic loading rates (OLRs) under long-term treatment. To enhance technological feasibility, this work presented a two-stage Anaerobic Membrane Bioreactor (2 S-AnMBR) composed of a hydrolysis reactor (HR) followed by an anaerobic membrane bioreactor (AnMBR) for long-term co-digestion of food waste and kitchen wastewater.

The OLRs were expanded from 4.5, 5.6, and 6.9 kg COD m− 3 d− 1 to optimize biogas yield, nitrogen recovery, and membrane fouling at ambient temperatures of 25–32 ◦C. Results showed that specific methane production of UASB was 249 ± 7 L CH4 kg− 1 CODremoved at the OLR of 6.9 kg TCOD m− 3 d− 1.

Total Chemical Oxygen Demand (TCOD) loss by hydrolysis was 21.6% of the input TCOD load at the hydraulic retention time (HRT) of 2 days. However, low total volatile fatty acid concentrations were found in the AnMBR, indicating that a sufficiently high hydrolysis efficiency could be accomplished with a short HRT. Furthermore, using AnMBR structure consisting of an Upflow Anaerobic Sludge Blanket Reactor (UASB) followed by a sidestream ultrafiltration membrane alleviated cake membrane fouling.

The wasted digestate from the AnMBR comprised 42–47% Total Kjeldahl Nitrogen (TKN) and 57–68% total phosphorous loading, making it suitable for use in soil amendments or fertilizers. Finally, the predominance of fine particles (D10 = 0.8 μm) in the ultrafiltration membrane housing (UFMH) could lead to a faster increase in trans-membrane pressure during the filtration process.