Groundwater Under Direct Influence of Surface Water, What To Do?
Transcription
Groundwater Under Direct Influence of Surface Water, What To Do?
Groundwater Under Direct Influence of Surface Water, What To Do? Presented by: Michael S. Johnson, P.E. Buck, Seifert & Jost, Inc. Presented at: American Water Works Association (AWWA) Annual Spring Conference, Atlantic City, NJ March 17-20, 2015 Outline LT2ESWTR Treatment Techniques EPA Factors that trigger compliance UV, Filter, Chemical, etc. Case Studies Two (2) wells Start up/Operation Procedures Background LT2ESWTR Improve drinking water quality Protection from disease causing microorganisms and contaminants Applies to all PWS that use SW or GWUDISW GWUDISW Factors (varies by state) Type of well (spring, horizontal collection well, unconfined aquifer or recharge well) Adjacent to surface water Well Construction (shallow/deep, annular space) Water Quality (periodically +TC or +E. Coli) Background Hydrogeological Investigation Hydraulic connection (seismic reflection survey, seepage investigation, or thermal infrared imagery) Microscopic Particulate Analysis (MPA) Low, Medium, or High Risk Algae, Diatoms, Pollen, Protozoa, Giardia, Crypto, etc. You, after Medium or High Risk MPA? LT2 Rule 2-log Crypto (or 5.5 if raw water not monitored) 3-log Giardia, and 4-log Virus Treatment Options Watershed Control Alternative Source/Intake Bank Filtration Pre-sedimentation Lime Softening Filter Chlorine Dioxide Ozone UV Membrane Filtration Filters Refer to State Standards Bag and Cartridge Filters Operator licensing Low Loading capacity for small systems Discard filter after expended Effectively removes Crypto (2-5 μm) and Giardia (5-10μm) Challenge Testing Product specific, not site specific o o o Full scale Challenge particulate Test solution concentration Up to 2 log for bag or cartridge filter showing 3 log removal Up to 2.5 log removal in series showing 3 log removal Filters Advantage Low maintenance, low capital, minimal training Disadvantage NSF, Headloss, Replace filters, redundancy, biofilm clogging, limit surges, larger flows consider membrane or other Filters Turbidity < 3NTU or less depending on manufacturer, may need pre-treatment UV treatment may require pre-treatment if >1 NTU MPA proof after installed? Ultraviolet (UV) Damages microorganisms and prevents replication No residual Validation testing, see UV Disinfection Guidance Manual In English Partial Exhibit 13.1 UV Dose Requirements – mJ/cm2 Ultraviolet (UV) Two (2) types of UV devices typically used: 1. Medium Pressure (MP) and 2. Low Pressure High Output (LPHO) More information see Ultraviolet Disinfection Guidance Manual at: http://www.epa.gov/OGWDW/disinfection/lt2/ pdfs/guide_lt2_uvguidance.pdf Ultraviolet (UV) LPHO vs. MP Reactors can be s-shaped, u-shaped, or in-line Lamp life LPHO 8,000 to 12,000 hours MP 4,000 to 8,000 hours Power Typically LPHO require larger footprint LPHO require less power, more lamps Sleeve Cleaning LPHO use Off-line chemical clean (OCC) systems, more labor MP use On-line Mechanical (OMC) systems, more parts to replace Ultraviolet (UV) Examples of: S-Shape U-Shape In-line Ultraviolet (UV) Validation of UV device No increasers US or DS within 10 times diameter of reactor PWS monitor for flow rate, lamp status and UV intensity UV absorbance (or UVT) if in dose monitoring strategy Fouling: Ca+2, Alkalinity, Mn+2, pH, Fe+2 and Hardness Off-spec reporting Advantages: Lowest cost treatment for Crypto and Giardia, no DBP, not impacted by pH or temperature Disadvantages: no residual, high UV dose for Virus inactivation, power quality Full Scale Implementation Example 1 200gpm well @ 360TDH, 200’ Deep Well 12’ x 22’ Wellhouse Seaquest and Hypo Wetlands nearby Prior to Construction From Determination of GWUDISW, 18 Month Schedule To Implement Full Scale Implementation As Constructed Construct within existing building New 200gpm @ 454 TDH VTP Waste/blow off piping Harmsco MUNI-3-3FL Full Scale Implementation As Constructed Harmsco MUNI-3-3FL InLine 200+ DVGW UV 6”x6” Tee Flow meter Surge Antic. Valve M.O. Spring Return BFV 35LF of 36”Ø DIP Full Scale Implementation Example 2 1200gpm well @ 609TDH, 55’ Deep Well 16’ x 13’ Wellhouse Seaquest and Hypo Floodplain and High Pressure From Determination of GWUDISW, 18 Month Schedule To Implement Prior to Construction Full Scale Implementation Prior to Construction Full Scale Implementation Raise All Treatment Components New 1400gpm @ 372 VTP (Lower head) New Elevated Treatment Enclosure Full Scale Implementation Parallel Treatment Trains With And Without Grating Full Scale Implementation As Constructed UV Reactor Y-Strainer Full Scale Implementation As Constructed Surge Anticipating Valve Spring Return Hydraulic BFV Booster Pump Surge Anticipating Valve Vault Summary NSF Listing UV Validation UV and Filter Treatment: multiple barriers Think Vertical Start-up and testing Learning Process o We were assisted by and would like to thank: Entire staff at United Water special mention to: Gerry Remsen, III, P.E. Bill Prehoda, P.G. Nick Curcio Bob Raczko, P.E. Sam Rulli, P.E., Rockland County DOH Dan Miller, Ph.D, Rockland County DOH Brock Rogers, P.E., NYS DOH Ronald von Autenried, P.E., BS&J J. Fletcher Creamer & Son, Inc. (Contractor) Aquionics Inc. (UV) Harmsco Filtration Products (Filter) Quality Controls, Inc. (Fail Safe BFV) Baker Manufacturing Company, LLC (Booster Pump) Thank you! Michael Johnson msj@bsjinc.com 201-767-3111, ext. 111