140 likes | 150 Views
Preserving & Enhancing. the Global Water Environment. Experiences with Alternative Supplemental Carbon Sources at 4 BNR Facilities. Katya Bilyk, PE and Paul Pitt, PE, PhD. July 2, 2009. Project Overview.
E N D
Preserving & Enhancing the Global Water Environment Experiences with Alternative Supplemental Carbon Sources at 4 BNR Facilities Katya Bilyk, PE and Paul Pitt, PE, PhD July 2, 2009
Project Overview Alternative carbon donors (glycerin and sugar water) for denitrification were tested at four BNR wastewater treatment plants in North Carolina and Virginia
Key Questions this Study Aimed to Answer • Are the alternative carbon donors effective for enhancing denitrification? • Which carbon sources are the most cost competitive with methanol? In all cases carbon was added to 2nd anoxic zone
Corn Syrup/Sugars • Glucose, fructose, corn syrup, molasses, soft drink bottling waste and food industry byproducts • High yield – ↑ solids production • No major health or safety issues • Product inconsistency
Full-Scale Experimental Setup Neuse River WWTP Henrico Co. WRF
Full-Scale Experimental Setup Parkway SDWRF
Process Monitoring Techniques • Full-scale anoxic zone profiles • Product sampling for COD content • Over 30 Denitrification Rate Batch Tests • Seed with mixed liquor from second anoxic zone • Purge with nitrogen gas • Spike with potassium nitrate in excess • Add carbon donor • Monitor DO, pH, NOx, and COD over time • Quantify SDNR and COD:N ratio
Alternative Carbon Testing Outcomes • Glycerin & corn syrup effectively reduced effluent NO3 and performed comparably to methanol. • DO entering the post-anoxic zone exerts a carbon demand. Careful DO control required to optimize carbon.
Cost Comparison of Carbon Alternatives • Pricing Typically in Terms of $/gallon Product • Comparison Basis - Cost per Pound of Nitrate Removed • This method considers all applicable variables: • Solution strength • Density • COD content • Cost per gallon • Anoxic yield
Carbon Cost Comparison: Glycerin and Ethanol most Competitive with Methanol
Questions kbilyk@hazenandsawyer.com Thank you to my coauthors: Joe Rohrbacher, P.E., Theresa Bruton, P.E., Paul Pitt, PhD, P.E., and Ron Latimer, P.E.