WATEREUSE LA CHAPTER MEETING ‐ ber 2013 INITIAL EXPANSION OF OCWD GWRS 8 Octob ANDREW LAZENBY, SUNNY WANG, AND MEHUL PATEL
INITIAL EXPANSION OF ORANGE COUNTY WATER DISTRICT'S ORANGE COUNTY WATER DISTRICT S GROUNDWATER REPLENISHMENT SYSTEM 2
OCWD GWRS PROJECT OBJECTIVES • Protect groundwater • Protect groundwater basins from seawater intrusion • Replenish local groundwater supplies • Provide multi ‐ barrier treatment system to meet drinking water t d i ki t requirements Schematics and Photos Courtesy of OCWD 3
OCWD GWRS PROCESS FLOW DIAGRAM MF MF Cleaning Compressed Sodium Backwash System Air Hypochlorite OCSD Plant No. 1 Secondary Secondary Effluent RO MF Transfer Filter Break Microfiltration Pump Screens Tank Station OCSD Plant No. 1 Sulfuric Acid and Sulfuric Acid and Anti-Scalant Addition OCSD Ellis Ave. Interplant Sewer Hydrogen RO Flush Peroxide System To Decarbonator Reverse Osmosis Barrier Injection Wells To Ultraviolet Kraemer/Miller ncentrate Irradiation System RO Spreading Cartridge Air RO Cleaning Feed Filters Basins System Pump RO Con S di Sodium Bisulfite To OCSD Ellis Ave. RO Flush Tank Interplant Sewer Sodium Lime To OCSD Ocean Outfall RO Flush Bisulfite FPWB To Santa Ana River Peak Flow and Emergency Bypass g y yp RO Bypass (SAR only) yp ( y) or OCSD Ocean Outfall 4
MULTI BARRIER TREATMENT SYSTEM • MF Pretreatment MF Pretreatment • Hollow fiber PVDF membranes, 0.2 um pore size • Removes bacteria, protozoa, and suspended solids • RO Membranes • Removes dissolved solids, viruses, organic compounds (including pharmaceuticals), etc. (including pharmaceuticals), etc. • Concentrate blended with WWTP effluent and discharged to ocean • Advanced Oxidation – UV/H O • Advanced Oxidation – UV/H 2 O 2 • Low pressure, high output system • Destroys trace organics • Removes NDMA and 1,4 Dioxane • Post ‐ Treatment Stabilization • Decarbonation to raise pH • Lime addition to stabilize RO permeate 5
EXPANSION PROVIDED AN OPPORTUNITY TO ENHANCE OPERATIONS AND RELIABILITY ENHANCE OPERATIONS AND RELIABILITY • Secondary effluent flow equalization provided to minimize diurnal flow variations and maximize production • Incorporated energy recovery devices (ERD) to new RO units to reduce energy consumption and energy consumption and prolong membrane life • New RO building layout to improve accessibility to improve accessibility to basement and pipe gallery • Pilot tested and implemented new lime slurry implemented new lime slurry system to enhance post ‐ treatment reliability 6
INCORPORATE ENERGY RECOVERY DEVICES TO REDUCE ENERGY CONSUMPTION Permeate (12 psi) Permeate (12 psi) 3.76 mgd 1.16 mgd 5 mgd 1.58 mgd 3.23 mgd 0.11 mgd 0 11 mgd 112 psi 112 psi 95 psi 95 psi 2.16 mgd 1 mgd 0.23 mgd 140 psi 124 psi 102 psi 149 psi 5.88 mgd g 2.7 mgd g 1.12 mgd g Feed 0.88 mgd 73 psi 82 psi Concentrate Energy recovery device w/motor gy y / 17.2 gfd 8.7 gfd 1.7 gfd Fluxes 14.4 gfd 12.2 gfd 3.8 gfd • Annual energy savings of approximately $17k per RO unit • Payback period of ERDs is approximately 5 years 7
IMPROVED OPERATION ACCESS IN NEW RO BUILDING 8
ALTERNATIVE POST ‐ TREATMENT TARGET TO IMPROVE STABILITY AND RELIABILITY IN IMPROVE STABILITY AND RELIABILITY IN WATER QUALITY • Alternative target mimics rain water quality for groundwater replenishment • Increased buffer intensity improves reliability • Increased calcium content better protects cement mortar lined pipes • Alternative target minimizes transport of metals within groundwater supply 9
LIME SYSTEM IMPROVEMENTS Existing Lime Slurry System Existing Lime Slurry System • Existing system is a flow paced system that is ramped up and down based on flow conditions (inconsistent reaction flow conditions (inconsistent reaction times in slurry make ‐ up tank) • Dry lime transfer system is susceptible to plugging and is controlled by screw conveyer speed d • Unable to keep up with peak lime demands New Lime Slurry System (RDP Lime Slaker System) • Lime slurry make ‐ up is controlled by weight, providing a greater level of accuracy over the existing flow paced system • Temperature controlled system to maintain optimum reaction conditions maintain optimum reaction conditions • Dry lime transfer system is not susceptible to plugging 10
PHOTOS OF RDP SLAKING SYSTEM PILOT TEST Lime Slurry Aging Tank y g g Lime Slaker Tank Lime Slurry Feed Slurry Transfer and Feed Pump 11 Assembly
CONSTRUCTION PHOTOS 12
CONSTRUCTION PHOTOS 13
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