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CHRP/Managers Meeting October 2009 Angelo Liberti, Chief Surface Water Protection Office of Water Resources 401.222.4700 ext 7225 angelo.liberti@dem.ri.gov
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NBC CSO Project Phase I tunnel - operational Nov 2008 Post storm monitoring Re-assess Rainfall Closure Criteria Phase II - preliminary design completed
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Current Plan for Managing Nutrients From WWTF 50% Reduction from RI WWTFs –DEM permits issued – June 2005 Comparable reductions from MA WWTFs
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Revised WWTF Nitrogen Limits 5 mg/l –UBWPAD –Woonsocket (3 mg/l) –NBC-Fields Pt. –NBC Bucklin Pt. –East Greenwich –No. Attleborough –Attleboro –Grafton –Uxbridge –Northbridge –(max extent) Limits May – October, require operation of treatment to remove N to max extent possible November-April –East Providence –Cranston –West Warwick –Warwick –Smithfield (10 mg/l) –Burrillville (max extent) - Warren – anticipated to address impacts to the Palmer River 8 mg/l
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Current Status of Load Reduction Efforts 8 - WWTFs have complete upgrades (2 require additional modifications) 1 - Under construction NBC Fields Point (completion by 12/31/2013) 1 – Planning Underway Woonsocket (Plan was due 8/09, construction by 3/2014) 2 - Design Underway NBC Bucklin Point East Providence (due 6/01/10, construction by 9/2012 Approximately 30% reduction in RI WWTF load achieved in 2005. Next significant reduction May 2014
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Status of Compliance with Revised Permit limits for N MA WWTFs North Attleborough 8 mg/lEPA issued 2/08; appeals settled (complete construction late 2012) Attleboro 8 mg/lEPA issued 6/08; Permit upheld on appeal. EAB decision issued 9/15/09. Upper Blackstone (UBWPAD) 5 mg/lEPA issued 8/08; appeals filed. Oral arguments before EAB 10/29/09 Grafton 8 mg/lNo action to date Uxbridge 8 mg/lNo action to date Northbridge NAEPA issued 9/06; reduce N to max extent
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Status of Compliance with Revised Permit limits for N RI WWTFs LimitStatusAve TN (mg/l) 5/07-8/08 Cranston 8 mg/lConstruction comp. –1/2006. Additional modifications to achieve TP = 0.1 mg/l and consistently achieve TN May-Oct complete construction by 3/31/2013 8.2 Warwick 8 mg/lConstruction comp. -11/2004 Additional modifications to achieve TP = 0.1 mg/l and consistently achieve TN May-Oct 8.0 West Warwick 8 mg/lConstruction comp. -7/2005. Additional modifications to achieve TP = 0.1 mg/l 9.2 (7.5)* East Greenwich 5 mg/lConstruction comp.–3/20064.0 East Providence 8 mg/lFinal Design due 6/01/10 Construction Deadline 9/2012 12.3 NBC- Bucklin 5 mg/lInitial Construction Complete 2006 FP approval 10/09, NBC requested 1year 5 months for design. 7.5 * Excludes May data (19.5, 13 mg/l)
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Status of Compliance with Revised Permit limits for N RI WWTFs (Cont.) LimitStatusAve TN (mg/l) 5/07-8/08 NBC -Field Pt 5 mg/lDesign Approved 09, Complete Construction 12/31/2013 13.7 Woonsocket 5 mg/lConstruction Comp. 2002 Agreed to complete construction for 3 mg/l by 3/2014 6.7 Burrillville Max extent TN Reductions since 200210.5 (7.7)* Smithfield 10 mg/lConstruction comp. -6/2006. Additional changes to consistently meet TP April-Oct 8.3 Warren Anticipated that Warren will need to reduce N to address impacts to the Palmer River 17.7 Westerly Construction comp. 10/036.3
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Nitrogen Reduction Projections Nitrogen removal at 11 RI WWTFs - reduces their summer season nitrogen loading by 65%, dropping to 48% as WWTF flows reach approved design flows.
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Comparison of MERL Experiments to Providence/Seekonk System
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Allowable Loading Condition
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Table 4: Approved WWTF design flows and design flows used for the load evaluations. Evaluation of WWTF Load Reductions
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Loading Condition Vs. WWTF Load Reductions
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Loading Condition Vs. Cost
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Anticipated RI WWTF Load Reductions
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Average Chlorophyll vs N Load y = 0.62 x + 6.32 R 2 = 0.94 0 10 20 30 40 50 60 70 0102030405060708090100 Nitrogen Load (mmol/m 2 /d) Chlorophyll a (ug/l) 32 X 16 X 8 X 4 X 2 X 1 X C Allowable Loading Condition
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