Achieving Effluent Limits While Treating an Intermittently Deficient Wastewater MWEA September 27, 2018

Transcription

1 Achieving Effluent Limits While Treating an Intermittently Deficient Wastewater MWEA September 27, 2018 By: Roger Gillard DWTF Bryan Wagoner, P.E. - DTW Warren Evans Wayne County Executive Chad Newton, A.A.E. WCAA Interim CEO

2 Overview 1. Objectives 2. Plant Information 3. Investigation 4. Solution & Results 5. Summary & Conclusion 6. Questions

3 Objectives

4 Purpose of the Project To Determine Causes of seasonal non-performance. Possible impacts from deicing fluid runoff discharges from Detroit Metropolitan Airport (DTW). To recommend Methods for preventing seasonal plant non-performance. Methods for establishing acceptable loading rates of deicing fluid discharges.

5 DTW Information

6 DTW 19 th busiest airport in North America (34.7 million passengers ,400 badged employees. Primary Delta Asia Hub. 1,140+ flights/day to more than140 destinations. 8,000 acre footprint. All stormwater detained on-site.

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9 Spent Deicing Fluid Management DTW has spent > $175 million on stormwater/deicing fluid management in the past 20 years. DTW operates the largest spent aircraft deicing fluid management system in the world. DTW recycles more propylene glycol than any airport in the world. More than 450,000 gallons of pure PG last year. Spent deicing fluid runoff that cannot be recycled is discharged to either the Downriver or GLWA Treatment Facilities.

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12 Plant Information

13 Process Train consists of the following: Screening & grit removal FeCl 3 addition for P removal Primary sedimentation High purity oxygen activated sludge UV disinfection Primary & secondary sludge co-thickening Belt filter press Landfill of sludge Downriver WWTF (Located about 15 miles south of Detroit)

14 Wastewater Characteristics 95% Residential/Commercial 10 Separated communities. 3 Combined communities. 5% Industrial 45 Significant Industrial Users. With exception of DTW industrial discharges are year-round. On Average 20% of cbod 5 loading is from DTW - Aircraft Deicing Fluid (ADF) runoff during winter & springs The ADF used at DTW is typically 88% propylene glycol, 1-2% other additives (corrosion inhibitors, and surfactants)s

15 Downriver WWTF Dry weather flow = MGD Wet weather flows = up to 225 MGD Influent Pump Station (IPS) Tunnel Pump Station (TPS) MGD MGD P r e l im Primary MGD i MGD MGD Treatment MGD MGD n a r y MGD MGD Secondary Treatment Type of treatment MGD % Preliminary % Primary only % Secondary only 75 33% Both primary and secondary 50 22% Total treated (uv) % UV Disinfection

16 Investigation (Jan 99 - Aug 03)

17 Problem Non-performance problems for Winter/Spring months (Dec-May). Poor-settling AS was not caused by filamentous microorganisms. Final Effluent cbod, TSS, TPx cbod TSS TP x Feb-99 Apr-99 Jun-99 Aug-99 Oct-99 Dec-99 Feb-00 Apr-00 Jun-00 Aug-00 Oct-00 Dec-00 Feb-01 Apr-01 Jun-01 Aug-01 Oct-01 Dec-01 Feb-02 Apr-02 Jun-02 Aug-02 Oct-02 Dec-02 Feb-03 Apr-03 Jun-03 Aug-03 mg/l Month and Year

18 SVI increased steadily and also higher values during winter/spring. Long-term upward trend is due to lower plant recycle TSS. Seasonal high is due to viscous exocellular polymer. Sludge Volume Index, mg/l Month Jan-99 Mar-99 May-99 Jul-99 Sep-99 Nov-99 Jan-00 Mar-00 May-00 Jul-00 Sep-00 Nov-00 Jan-01 Mar-01 May-01 Jul-01 Sep-01 Nov-01 Jan-02 Mar-02 May-02 Jul-02 Sep-02 Nov-02 Jan-03 Mar-03 May-03 Jul-03 Month and Year

19 Exocellular Polymer (ECP) India-Ink-Stained ECP No or very little ECP

20 Viscous Bulking Causes Micronutrient Deficiency a) Iron and /or other trace metals Macronutrient Deficiency N and/or P High F/M F/M 0 Month Jan-99 Mar-99 May-99 Jul-99 Sep-99 Nov-99 Jan-00 Mar-00 May-00 Jul-00 Sep-00 Nov-00 Jan-01 Mar-01 May-01 Jul-01 Sep-01 Nov-01 Jan-02 Mar-02 May-02 Jul-02 Sep-02 Nov-02 Jan-03 Mar-03 Month and Year

21 Soluble P Soluble P = TP TSS Estimated Final Effluent Soluble P, mg/l Month Jan-99 Mar-99 May-99 Jul-99 Sep-99 Nov-99 Jan-00 Mar-00 May-00 Jul-00 Sep-00 Nov-00 Jan-01 Mar-01 May-01 Jul-01 Sep-01 Nov-01 Jan-02 Mar-02 May-02 Jul-02 Sep-02 Nov-02 Jan-03 Mar-03 May-03 Jul-03 Month and Year

22 P Deficiency The challenge we faced was to prevent P deficiency while meeting P limit of 1.0 mg/l. The solution involved limiting cbod 5 /TP ratio to avoid P deficiency (approx. 40/1). Effect of PE cbod 5 /TP ratio on Soluble P PE cbod5/tp Ratio Final Effluent Soluble P, mg/l

23 Metals Solubility

24 Solution and Results

25 The Solution Adjust FeCl 3 dose to raw Wastewater to allow sufficient P pass through primary tanks to meet primary effluent cbod 5 /TP of 40/1. Influent Pump Station (IPS) Fe Cl 3 Tunnel Pump Station (TPS) MGD MGD P r e l im Primary MGD i MGD MGD Treatment MGD MGD n a r y MGD MGD Secondary Treatment 1. Bypass around secondary 2. UV lamp fouling UV Disinfection

26 Primary Effluent cbod 5 /TP Primary Eff cbod/p Ratio (7-day moving Avg.) Jan Jan-02 2-Mar-02 1-Apr-02 1-May May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep-05

27 Summary of Adopted Procedures Prior to the glycol season, the Airport starts discharging ADF runoff at 1,000 lbs/day of cbod 5 to acclimate the microorganisms at the plant. The daily flow rate of ADF runoff is uniform over a 24-hr period. Increases or decreases in cbod 5 loading are capped at 1,000 lbs./day. Maximum loading of 20,000 lbs./day. Monitor primary and final effluent P using a Chemscan UV-4100 analyzer.

28 The Results Number of Monthly Exceedances Jan 99 - Aug 03 Nov 03 - Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec There were zero exceedances for the seven

29 Summary and Conclusions

30 Summary & Conclusions Investigation showed that P deficiency was the cause of noncompliance. Addition of FeCl 3 and ADF discharge caused the P deficiency. P deficiency reduced activated sludge settling due to viscous bulking. Plant was brought back to compliance by maintaining a primary effluent cbod 5 /TP ratio of less than 40/1. This was achieved by adjusting FeCl 3 dose and with close cooperation between the plant and the Airport.

31 Activities and Accomplishments to Date Operational Parameter Status DATE: 04/10/06 Final Effluent Value O.K. Warning Trouble TSS TP Sol. P D.O Fecal Coli Transmittance (lab) Primary Effluent TSS TP Secondary Process MLSS 2,838 2, Sludge Age (6 days) SVI Solids Handling Sludge Production, tons Cake % solids 21.7% % - Mixed Liquor Supernatant cloudy? no X - Floating material? no X - Total 9 5 1

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35 Questions??????????????????