Advanced Primary Treatment Technologies for Carbon Diversion & Management at Water Resource Recovery Facilities

Presentation Description: Carbon diversion involves reducing the organic load on secondary systems by redirecting more biochemical oxygen demand (BOD) towards the solids line at the primary treatment stage, which reduces the aeration requirements for downstream aerobic biological treatment processes. The market for installing advanced primary treatment (APT) for carbon diversion is rapidly growing, with opportunities for chemical, physical and biological processes. Cloth disc, Proteus media, and compressible media filters are leading the way in primary filtration, while high-rate activated sludge processes, also known as A-stage or adsorption/bio-oxidation (A/B) processes are also gaining popularity as utilities seek alternatives to conventional primary treatment (CPT). Four APT technologies were evaluated at demonstration to full scale [from 20 gallons per minute (gpm) to higher than 1,000 gpm] in this project to replace or augment CPT system of primary clarification. These APT systems are: Cloth Disk Primary Filter (CDPF), Proteus Primary Filter (Proteus PF), Compressible Medium Biofilter (CMBF), and Micro-Screen (MS). Compared to primary clarifier which achieved 61% removal for total suspended solids (TSS) and 37% removal for chemical oxygen demand (COD), CDPF, Proteus PF, and CMBF demonstrated significantly higher removal performances. The CDPF achieved 82% removal for TSS and 53% removal for COD. Proteus PF achieved 85% removal for TSS and 65% removal for COD. The CMBF achieved 81% removal for TSS and 63% removal for COD. The MS showed a comparable performance to primary clarifier with TSS and COD removal efficiencies of 65 and 42%, respectively. Significant footprint reductions were also observed (ranging from 40% to 70 %) for all of the APT technologies compared to CPT. To demonstrate the full benefits of advanced wastewater treatment, carbon diversion and management strategies were evaluated as part of this technology research and demonstration project conducted for the California Energy Commission at Linda County Water District’s Water Resource Recovery Facility (Olivehurst, CA). Following significant energy benefits were observed for CDPF, CMBF, and Proteus technologies when compared to primary clarifiers: (1) 20 to 40% decrease in secondary treatment aeration energy requirement, and (2) 30 to 40 % increase in gas energy production in anaerobic digester.

.1 SWRCB Education Units