State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China; Advanced Water Management Centre (AWMC), The University of Queensland, QLD, 4072, Australia. Electronic address: [Email]
It is a technical barrier to efficiently treat traditional Chinese pharmaceutical (TCP) wastewater, due to its high chemical oxygen demanding (COD) concentration (>5000 mg/L). This study proposed and employed a spiral symmetry stream anaerobic bioreactor (SSSAB) to treat TCP wastewater. Results showed that a pilot-scale SSSAB (150 L) could achieve COD removal efficiency of 94.8% and volumetric removal rate (VRR) of 19.7 ± 0.7 kg COD·(m³·d)-1 under room temperature, which were much higher than operation performance in internal circulation (IC) anaerobic reactor (COD removal efficiency and VRR were 85% and 11.3 ± 0.8 kg COD·(m³·d)-1, respectively). The maximum COD volume removal rate could attain 43.4 kg COD·(m³·d)-1. The characteristics of granular sludge in SSSAB were investigated from both temporal and spatial scales. During the operation period, the anaerobic granular sludge in SSSAB was of higher concentration and superior properties compared to the IC anaerobic reactor. The sludge concentration exhibited a spatially decline trend, decreasing from 61 g L-1 in the bottom to 34 g·L-1at the top of the bed, yet the average biomass concentration was still higher than that in IC reactor. According to shock tests with fluctuated real wastewater. the resistance of SSSAB to hydraulic and loading shock was up to 4.3 m h-1 and 42 (kg COD· h) · (m3)-1, respectively. The study demonstrated the proposed SSSAB is a promising reactor to treat high-concentration TCP wastewater.