Demonstration of Biofiltration Technology for Carbon Diversion

Dr. Caliskaner was the principal investigator and project manager of the biofiltration / carbon diversion technology development and demonstration conducted for the California Energy Commission. The project includes biofiltration of wastewater before the secondary treatment to achieve aeration energy savings up to 30-40 percent compared to conventional primary treatment while increasing the plant performance and capacity. The biofiltration system at the Linda County Water District’s Water Resource Recovery Facility was operated in parallel with the other primary filtration system [using cloth disk primary filter (CDPF)] to compare performances of different carbon diversion/advanced primary treatment technologies. Biofiltration also offers the potential for removing soluble organic fractions due to biological activity, which occurs because of the increased depth of the filter medium and longer contact times.Treatment performance for the primary clarifier, CDPF, and biofilter was monitored with laboratory analysis (24-hour composite samples twice per week) and continuous inline turbidity monitoring. The primary clarifier achieved an average removal of approximately 59, 40, 40, and 16% for total suspended solids (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), and Total Kjeldahl Nitrogen (TKN), respectively. The CDPF system achieved average removals of 80, 56, 55, and 20% for TSS, BOD, COD, and TKN, respectively. The biofiltration system achieved average removals of 69, 55, 50, and 16% for TSS, BOD, COD, and TKN, respectively. Additionally, the biofilter achieved average removals of 25 and 22% for soluble COD and soluble BOD, respectively. Observed benefits of primary biofiltration technology include: 

• Enhanced biological treatment performance during secondary treatment, based on the increased primary treatment performances and reduced particle sizes in the effluent.  
• Increased gas energy production in the anaerobic digestion process, resulting from the high organic energy content of the volatile suspended solids removed by the biofilter.
• Increased secondary treatment capacity due to a reduced loading of TSS and BOD to activated sludge basins.