Optimizing Nutrient Removal PNCWA - Southeast Idaho Operators Section Pocatello, ID February 11, 2016 Jim Goodley, P.E.
Types of Optimization
Outline Wastewater Characterization BNR Optimization N Removal P Removal Physical-Chemical
Types of Optimization Pollutant Removal- Nutrients Capacity- Flow/Loading Energy Use-Efficiency Operating Costs Effluent Stability Etc., Etc.
Total COD Biodegradable COD Slowly Biodegradable COD Readily- Biodegradable COD Colloidal COD Particulate COD Complex Soluble COD VFA COD Non-Biodegradable COD Soluble COD Particulate COD Important for BNR
Wastewater Characterization COD Readily Biodegradable rbcod (soluble) Soluble Complex COD e.g. Fermentable Volatile Fatty Acids (VFA s) aka SCFA- short chain fatty acids Filter (0.45um ) to determine soluble (includes colloids) vs. particulate components Carbon source for: EBPR- Phosphorus Release Pre-denitrification
Total TKN Organic Nitrogen Biodegradable Organic N Non-Biodegradable Organic N Soluble Organic N Particulate Organic N Particulate Organic N Soluble Organic N (rdon) Free Ammonia (NH 4 -N) Total Nitrogen Nitrate/Nitrite NO 3 -N/NO 2 -N Typically 1-2 mg/l
Total Phosphorus Organically Bound Phosphorus Non-Biodegradable Organic P Biodegradable Organic P Soluble Organic P Particulate Organic P Particulate Organic P Soluble Organic P Orthophosphate (soluble) Typically Largest Fraction (60-80%of TP)
BNR Process Fundamentals Predominant Conditions P Removal : Anaerobic Aerobic EBPR- Enhanced Biological Phosphorus Removal N Removal: Anoxic Aerobic N&P Removal: Anaerobic-Anoxic-Aerobic BNR Process Challenge: Conflicting Environments
Optimizing Nitrogen Removal Nitrogen Removal Requirements Series Anoxic & Aerobic Conditions Carbon Source Internal (Nitrate) Recycle TKN NH 3 -N NO 3 -N NO 2 -N Org-N
Optimizing Nitrogen Removal True Anoxic- No/Very Low Dissolved Oxygen Internal Recycle- Make Sure D.O. is low, < 0.5 mg/l Influent (Aerated Grit Removal) Mindful of Aeration Design- Low Loading Periods Provide Turndown Consider jockey Blower Do not entrain air Vortexing Cascades
Optimizing Nitrogen Removal Substrate (Carbon) Sources Internal Sources: Influent, Fermenter rbcod/scfa/vfa s Analyze Your Influent (WW Characterization) External Sources Methanol Micro-C, glycerine Other Sources- Beverage/Food Processing Wastes Affects/Impacts Denitrification Rate
Optimizing Nitrogen Removal Internal Recycle Make sure the rate is optimal Put VFD s on Pumps Too High Nitrate Concentration Optimized HRT Too Low
Optimizing Nitrogen Removal Source: USEPA Nitrogen Control Manual
Aerobic Optimizing Nitrogen Removal Internal/Nitrate Recycle N03 Secondary clarifier Influent Anaerobic Anoxic Aerobic Anoxic Effluent Return activated sludge Sludge Control based on NO 3 -N Concentration at end of pre-anoxic zone Use on-line NO 3 -N analyzer IF NO 3 -N = 0 mg/l THEN increase IRQ flow rate IF NO 3 -N ~ 0-0.5 mg/l THEN no change IF NO 3 -N >0.5 mg/l THEN decrease IRQ flow rate
Optimizing Nitrogen Removal Swing Zone- Flexibility to Adapt Volume Inf. Internal Recycle 1 2 3A 4A 5 6 3B 3C 4B Return Sludge Swing Zone Winter Aerobic, need volume for nitrification Summer- Anoxic, enhance denitrification
Optimizing Phosphorous Removal Enhanced Biological Phosphorous Removal (EBPR) EBPR Requirements Series Anaerobic-Aerobic Conditions (Luxury Uptake) Carbon Source Solids Removal Chemical Removal Metal Salts- Ferric or Alum Typ. Mixing is Key
Optimizing Phosphorous Removal Anaerobic Conditions NO Dissolved Oxygen NO Nitrate Check P Release
Optimizing Phosphorous Removal Carbon (Readily Biodegradable) Volatile Fatty Acids COD:P Ratio (>45:1) Fermentation External Sources Methanol Glucose
Optimizing Phosphorous Removal Process Sidestreams Solids Handling Phosphorus Recycling Anaerobic Conditions (Unwanted P Release) Solids Dewatering- High P Load Sidestream Treatment Once it s out, keep it out
Optimizing Phosphorous Removal Physical-Chemical Methods Physical Filtration Remove TSS that contain phosphorus and Remove chemical solids, bound phosphorus
Optimizing Phosphorous Removal Physical-Chemical Methods Chemical Metal Salts Alum Ferric
Questions?