at the Stic ickney Water Reclamation Pla lant January 29, 2019 - - PowerPoint PPT Presentation

Phosphorus Recovery ry at the Stic ickney Water Reclamation Pla lant

January 29, 2019

Background

Nutrient Standards Development

Ecoregion VI, Corn Belt and Great plain: 0.076 mg/L TP and 2.18 mg/L TN 2001 – PRESENT IEPA developing defensible nutrient standards (1 mg/L TP as monthly average for new and expanding WWTPs) 1998 USEPA initiated nutrient criteria development 2000 USEPA finalized 14 ecoregional nutrient criteria recommendations for streams and rivers 2011 IEPA renewed its efforts to develop nutrient standards with 4 working groups 2000 IEPA requested to develop nutrient standards for the state 2006 IEPA/IPCB promulgated the Interim P Rule 2015 IEPA finalized the Illinois Nutrient Loss Reduction Strategy

District Nutrient Efforts – Strategic Plan for Resource Recovery and Sustainability

Incorporated nutrient standards into master plans 2001 – PRESENT Actively participating in IEPA Nutrient Standards development 2002 Formed Nutrient Task Force to identify needs 2011

• Informed IEPA on steps:

− To biologically remove P using existing infrastructure − Recover P where possible − To work within District’s long term strategic plan on resource recovery and sustainability 2005 Conducted pilot nutrient removal test for a WERF project 2007-08 Conducted full scale study at Egan WRP using chemical P removal method 2012 Formed a District-wide Phosphorus Task Force to study and implement of EBPR Full-scale test in one battery at the Stickney WRP 2013 Converted all SWRP to EBPR configuration Awarded contract for construction of a P recovery facility at SWRP 2014 New NPDES permit with special condition for new P limit to be met by 2018

P Removal l from Main instream

Sti Stickney Water Recla lamation Pl Plan ant

• Serves 2.38 million people
• Flows:

−Avg Design Capacity: 1,200 MGD −Average 2014-16: 700 MGD

• 4 aeration batteries

− 8 tanks/battery − 4 passes/tank − 96 circular secondary clarifiers

Battery D Battery C

Battery A Battery B

Conversion for EBPR (AAnO) ) at t th the St Stickney WRP

Anoxic zone Aerobic zone Anaerobic zone

P1 P2 P3 P4 Mixing Channel NS RAS Channel PE RAS Influent Channel EW RAS Channel

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 May-12 Jun-12 Jul-12 Aug-12 Sep-12 Oct-12 Nov-12 Dec-12 Jan-13 Feb-13 Mar-13 Apr-13 May-13 Jun-13 Jul-13 Aug-13 Sep-13 Oct-13 Nov-13 Dec-13 Jan-14 Feb-14 Mar-14 Apr-14 May-14 Jun-14 Jul-14 Aug-14 Sep-14 Oct-14 Nov-14 Dec-14 Jan-15 Feb-15 Mar-15 Apr-15 May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Jan-16 Feb-16 Mar-16 Apr-16 May-16 [TP] @ PE (mg/L) [TP] @ Outfall, Battery D (mg/L) ST Plant Outfall TP PE WEIGHTED TP

Sti tickney EBPR Progress – Monthly Means

PE TP: 7.6 mg/L Outfall TP: 0.86 mg/L PE TP: 4.7 mg/L Outfall TP: 1.16 mg/L

P Recovery ry

P Recovery Process

Principle of Operation

• Use of centrate and P-rich streams in WWTPs as

feed

• Streams pumped upward through the bottom of the

reactor

• Supersaturation conditions as driving force
• Inject NaOH to raise pH to 7.7
• Inject MgCl2 at a molar ratio of 1.1:1 (Mg:P)
• Spontaneous crystal nucleation occurs
• Deposition on surface of crystals occurs as chemical

driving force reduces

• Crystals grow through this precipitation
• Pellets recycled for further growth

Recovered Product

• High purity struvite (99.5% struvite)
• Composed of Phosphorus, Nitrogen, and

Magnesium MgNH4PO4•6H2O

• Utilized as a slow release fertilizer – 5-28-0+10%
• Enhanced efficiency fertilizer
• Reduces risk of nutrient run-off

P Recovery at SWRP

Construction Dates

• Startup of Facility: 5/2016
• Operations test ongoing

Description of SWRP Facility

• 3 Pearl 10,000 reactors at SWRP
• Sized to accept both post-digestion centrate and

pre-digestion centrate (from WASSTRIP)

• Estimated concentrations of orthoP in these

streams:

• Post-digestion Centrate: 50 – 200 mg/L
• WASSTRIPATE: 58 – 75 mg/L

(avg & max from benchscale experiments) Based on loading to facility, estimated production:

• With post-digestion centrifuge alone:

2,200 tons/year fertilizer

• With post-digestion centrifuge + WASSTRIPATE

7,700 – 9,600 tons/year fertilizer

Primary Anoxic/ Anaerobic Aerobic Anaerobic Digestion Dewatering (High P and Mg, low NH3) WASSTRIP Pearl Process Clarifiers Thickening Ferment- ation Thickening

Crystal Green Storage & Bagging

Dewatering Screen & Dryer

Pearl Reactors

500 1000 1500 2000 2500 3000 3500 4000 4500

• rthoP Removed (lbs/d)

Pounds of f ort rthoP Removed Daily fr from Post-Digestion Centrate

• Average: 1,800 lb/day
• Represents ~10% of the orthoP load

0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 [TP] @ PE (mg/L) [TP] @ Outfall, Battery D (mg/L) Stickney Plant Effluent TP Primary Effluent TP

Stickney EBPR Progress – Monthly Means

PE TP: 7.6 mg/L Outfall TP: 0.86 mg/L PE TP: 7.5 mg/L Outfall TP: 2017 – 0.64 mg/L 2018 – 0.30 mg/L PE TP: 4.7 mg/L Outfall TP: 1.16 mg/L

Chall llenges

Seed In Injector System

Cit itric Acid System Ext xtension

Sulfu furic Acid System

Chemicals

0.5 1 1.5 2 6.6 6.8 7 7.2 7.4 7.6 7.8 Base [mL] pH

Titration 1

2000 4000 6000 8000 10000 12000 14000 16000 7/19 7/29 8/8 8/18 8/28 9/7 9/17 9/27 10/7 10/17 10/27 Gallons/Week

Chemical Usage

NaOH MgCl2

Questions?

Y. . Mwende Lefle ler le lefl flery ry@mwrd.org