There s s Wastewater in the Geology

Transcription

1 There s s Wastewater in the Geology Introduction to Current RIBS Research CIB-STAC December 5, 2008 Scott Andres, Delaware Geological Survey

2 Hands-On Participants Delaware Geological Survey M. Turkmen*, E. Walther*, C. He, S. McCreary, H. Gittings,, E. Wolff*, T. McKenna, J. Tomlinson* Dept. of Bioresources Engineering W. Ritter, A. Chirnside*, I. McCann, A. Kiliszek* Dept. of Geological Sciences A. Beers*, N. Maier*, J. Howard*, H. Michael Dept. of Civil and Environmental Engineering P. Imhoff, M. Akhavan*,, M. Rivers* DNREC J. Barndt,, P. Boettcher*, S. Strohmeier*, J. Kasper*, A. Siegel*, P. Cooper, L. McDaniel, R. Stevens, K. Glanden,, H. Moore, J. Hayes, R. Graeber DPH Kevin Cottman Duffield Assoc. Inc J. Csoltka,, S. Smailer,, A. Klingbeil*, M. Neimeister* New Castle County Dept of Special Services

3 Acknowledgment$ DNREC - USEPA UD Water Resources Center State Water Resources Research Institute DGS

4 OVERVIEW Land Based WWD

5 Centralized Wastewater Treatment and Disposal traditionally speaking Public utility for the public good Provides ability to plan development More control over output of pollutants location, amount, and concentration Long term source of revenue for government Many complex interrelated issues

6 Privately Owned Wastewater Utilities new wrinkles on an old issue Ability to sell treatment services as an privately controlled commodity Some infrastructure costs shift from public to private sector Can bypass government planning and control over infrastructure and build out Economies of scale and land use denser development with central treatment Zoning approval before environmental approval

7 How to avoid or manage risks? Public and environmental health Problem mitigation Development&Income Costs for wastewater treatment and disposal

8 Rapid Infiltration Basin Systems High hydraulic loading rates of treated sewage effluent into the ground Wastewater treatment plant Infiltration basins Vadose zone (natural) treatment Diffusion/dispersion of water and solutes in aquifers Many misconceptions, miscommunications

9 RIBlets Decades of operational history Most commonly used in developing arid areas, and locations that are fresh water poor Water reuse and recycling Hydraulic barriers against saltwater movement High loading > smaller land requirement Regulation and standards are a?

10 Tale of Scales Discharge Rate (m/yr) 100 A chart would be better here! Natural recharge 330 to 380 mm/yr Septic System 1000 to 1300 mm/yr Spray Irrigation 2550 to 3000 mm/yr RIBS 25 to 40 m/yr 1 Aerial photos time series of Rt 1 corridor Natural Septic Spray RIBS

11 RIBS Research Phase I Treatment plant performance, site visits, comparison of state regulatory programs Phase II Field experiments - infiltration beds, vadose and saturated zones, monitoring systems, site characterization methods Phase II Modeling experiments field site simulation, comparison of modeling approaches, GIS screening tools Phase III Reporting and wrap up Parallel SWRI project on vadose zone

12 WASTEWATER TREATMENT & RIBS - It s in the sauce!

13 Phase I Results Treatment plant performance shows mixed success periodic plant upsets,, some lemons,, start up and capacity gotcha s Other states have adapted engineering, regulation, and policy to water and development needs and environmental/public health risks DE public and environmental health risks are significant and different from other states DE regulatory and administrative programs are not complete Initial recommendations for siting and buffer distances

14 Phase II Field Experiments

15

16 Infiltration beds Small to large

17 Flooding in action

18 When things go wrong It s s a show stopper!

19 Infiltration issues and risks Hydraulic Failure COMMON but AVOIDABLE Too slow and too fast problems caused by Inadequate site characterization & facility design reliance on MAGIC SAND Inappropriate infiltration bed maintenance Poor quality effluent Poor application practices

20 Phase II Field Experiments

21 Soil and Vadose Zone Treatment Backstop/supplement to treatment plant Effectiveness dependent on hydraulics rates, timing, subsurface materials N - Mineralize, Nitrify, Denitrify P - Mineralize, Sorb Pathogens, metals, organics, etc. predation, graze, sorbtion, mineralize, oxidation, precipitation..

22 Infiltration issues and risks - geochemistry Little to no contaminant removal once past this zone and in an aquifer! Breakthrough of applied contaminants, mobilization of pre-existing existing contaminants Very complex system low risk design requires extensive work Problem diagnoses and fixes are costly Reliance on MAGIC SAND

23 Ground Water Benefits and Risks Recharge does occur Potential for re-use Contamination of key water resource Site specific flow details uncertain Monitoring is key risk management tool

24 Risks - Regional transport of contaminants, contact with sensitive receptors Proper design and monitoring reduce risk well stream Elevation (m) Flow paths 3.5 km

25 Flow Paths Pre RIBS Elevation (m) Land surface Water table Base of aquifer Distance (m) Mon. Well Sea level swamp

26 Flow Paths with RIBS Elevation (m) Land surface Water table Base of aquifer RIBS Distance (m) Mon. Well/CMT Sea level swamp

27 Testing Vertical Variations in Chemistry

28 Vertical variability 20 Effluent Concentrations Depth (ft) near mid far Ni45-43 Ni45-35 Ni NO3-N (mg/l)

29 Nitrate horizontal variability Infiltration beds Sea level swamp

30 SRP horizontal variability Sea level swamp

31 Flow Paths and Transport Elevation (m) exc high med Land surface Water table Base of aquifer RIBS Distance (m) Sea level swamp

32 No time to discuss details/ please stay tuned! Geology wrt GW quality, GW flow SEDIMENT CHEMISTRY As IN MARINE DEPOSITS WITH SULFIDES! INFILTRATION EXPERIMENTS FLOW AND TRANSPORT MODELING EMERGING CONTAMINANTS SITE SCREENING TOOLS

33 Questions