Process Monitoring for Biological and Chemical Nutrient Removal

Transcription

1 October 27, 2016 Process Monitoring for Biological and Chemical Nutrient Removal OWEA 2016 PLANT OPERATIONS & LABORATORY WORKSHOP

2 Agenda Why Consider Nutrient Removal? Nitrogen Monitoring & Removal Phosphorus Monitoring & Removal 2

3 Why Nutrient Removal? Required by Discharge Permit Improve Water Quality (avoid future limit) Increase Revenue (water quality trading) Stabilize Process Save Energy Recover Nutrients (P) 3

4 kwh / MG Energy Intensity Benchmarking 2,500 2,000 1,934 1,853 1,955 1,500 1,000 1, ,249 1,118 1,202 Typical Best Practice Basic Secondary Nitrification BNR ENR Joint WEF/WERF Webcast: Net Zero Energy Solutions for Water Resource Recovery Facilities Wednesday, October 29th, 2014

5 P Removal and Recovery Detergent Human Industry Plants WWTP P Recovery Fertilization Mining Weathering Agriculture Runoff Discharge X Phosphate rock Rivers & lakes Tectonic uplift Sedimentation Sediments Cornel et al (2009)

6 Nitrogen Monitoring 6

7 Cabinet Analyzer 7

8 Ion Selective Electrode 8

9 Specifications IQSN Nutrient ISEs Specification Ammonium Nitrate Potassium Chloride Measuring Range mg /L (as N)* Resolution mg /L (as N)* Response Time min. 0.1 to 100 / 1.0 to 2, to to 1, to to 1, to to 1, / / / 1.0 (as K) 0.1 / 1.0 (as Cl) < 3 9

10 Response Time 10 Automation of Wastewater Treatment Facilities, 3 rd Edition, WEF MOP-21, WEF Press, Alexandria, VA, 2007.

11 Optical 11

12 ISE vs. Optical Nitrate Monitoring - Optical ISE Measuring range, mg/l as N 60 / to 1,000 Resolution Pressure resistance, bar Power Consumption, W Up to Response time (t 90 ), min. Programmable < 3 Temperature measurement No Yes Additional Parameters / probe COD/BOD/TOC, NO 2, TSS NH 4, K, Cl Warranty (probe), yrs 2 2 Warranty (electrodes), yrs NA 1

13 Nitrogen Removal 13

14 The Microbiological Nitrogen Cycle OHO NO 2 - NOB AOB

15 Nitrogen Removal Configuration 3-4 Q NO 3 -N IMLR or NRCY WW Anoxic NH 3 BOD Oxic NO 3 -N NO 3 -N Clarifier NO 3 NO 3 N 2 NH 3 NO 3 RAS NO 3 -N 15

16 Delaware County RSD A N O A N O H Anoxic Oxic

17 Denitrification Process Control Chart 17

18 4-Stage Bardenpho 3-4 Q NO 3 -N Methanol or Glycerin Anoxic Internal MLSS Recycle Aerobic Anoxic Aerobic Q BOD NH3-N Aerobic 3-5 mg/l TN RAS NO 3 -N Distance

19 Denitrification Monitoring WSSC Seneca 5 x NitraVis 701 TS (1 in each train) w/ supplemental air cleaning (MIQ/CHV) Goals: Effluent < 4.0 mg N/L (permit) Effluent < 3.0 mg N/L ($300k credit) Minimize Methanol N 19

20 Step Feed Denitrification NYC DEP 63 x NitraVis 701 IQ Goals: Target Effluent TN = 7 to 8 mg N/L Monitoring of oxic zone nitrate Feed forward Feedback control of carbon addition (NIC-NOT) 20

21 Phosphorus Monitoring 21

22 Orthophosphate (PO 4 3- ) Environmental P is Phosphate Soluble P is orthophosphate Colorimetry is the primary method of detection

23 Phosphorus Characterization TP OP

24 Orthophosphate Analyzer Low reagent consumption Suitable for outdoors Automatic calibration Integrated permeate pump Filter module 24

25 Technical Specifications Range (mg P / L) Accuracy Lo: 0.05 to 15 mg P / L 2% or 0.05 Hi: 1 to 50 mg P / L mg P / L Response time (min.) Detection limit (mg P / L) Reagent Replenishment < mg P / L 2.5 L / 4 mths. 25

26 Phosphorus Removal 26

27 How is P Removed? 1. Biological 2. Chemical P Basic concept: P soluble P Particulate

28 Chemical P Removal Fe/ Al Fe / Al Fe / Al Fe / Al Pre-precipitation Simultaneous precipitation Post precipitation P P

29 Chemical Dosing Control Manual Flow-proportioned (Feed Forward) Feedback with analyzer 29

30 Feedback Control Example Fe P % 900 HOLD P 0.10

31 Chemical Dosing System Operation 31

32 Phosphorus Accumulating Organism (PAO)

33 A / O Process VFA RAS Concentrations in Bioreactor PAO P Anaerobic Ortho-P PAO P Aerobic 3 x Infl. Ortho-P P-Rich WAS PHB Storage BOD BOD Oxidized Net P Removal Location in Bioreactor

34 Flow Sheet GC Sugar Creek Effluent Ultraviolet Disinfection

35 Process Control - ORP

36 Summary There are many compelling reasons to consider nutrient removal Multiple reliable online monitoring technologies are available for nitrogen monitoring. Nitrogen removal is achieved through modification of the well-known activated sludge process to exploit the microbiological nitrogen cycle Online phosphorus monitoring requires a cabinet analyzer but the technology is improving to reduce maintenance and cost Phosphorus removal can be achieved chemically or through enrichment of phosphate accumulating organisms (PAO) 36

37 Questions? 37