WATEREUSE LA CHAPTER MEETING INITIAL EXPANSION OF OCWD GWRS

Transcription

1 8 Octob ber 2013 WATEREUSE LA CHAPTER MEETING INITIAL EXPANSION OF OCWD GWRS ANDREW LAZENBY, SUNNY WANG, AND MEHUL PATEL

2 INITIAL EXPANSION OF ORANGECOUNTY WATER DISTRICT'SS GROUNDWATER REPLENISHMENT SYSTEM 2

3 OCWD GWRS PROJECT OBJECTIVES Protect groundwater basins from seawater intrusion Replenish local groundwater supplies Provide multi barrier treatment system to meet drinking di water requirements Schematics and Photos Courtesy of OCWD 3

4 OCWD GWRS PROCESS FLOW DIAGRAM Sodium Hypochlorite MF Cleaning System Compressed Air MF Backwash OCSD Plant No. 1 Secondary Effluent Filter Screens Microfiltration MF Break Tank RO Transfer Pump Station OCSD Plant No. 1 OCSD Ellis Ave. Interplant Sewer To Barrier Injection Wells Decarbonator Hydrogen Peroxide Reverse Osmosis Sulfuric Acid and Anti-Scalant Addition RO Flush System To Kraemer/Miller Spreading Basins RO Flush Tank Air Sodium Bisulfite Ultraviolet Irradiation System RO Con ncentrate RO Cleaning System RO Feed Pump To OCSD Ellis Ave. Interplant Sewer Cartridge Filters To Santa Ana River or OCSD Ocean Outfall Lime RO Flush Peak Flow and Emergency Bypass FPWB Sodium Bisulfite To OCSD Ocean Outfall RO Bypass (SAR only) 4

5 MULTI BARRIER TREATMENT SYSTEM 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. Concentrate blended with WWTP effluent and discharged to ocean 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

6 EXPANSION PROVIDED AN OPPORTUNITY TO 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 prolong membrane life New RO building layout to improve accessibility to basement and pipe gallery Pilot tested and implemented new lime slurry system to enhance posttreatment reliability 6

7 INCORPORATE ENERGY RECOVERY DEVICES TO REDUCE ENERGY CONSUMPTION Permeate (12 psi) 3.76 mgd 1.16 mgd 5 mgd 3.23 mgd 1.58 mgd 140 psi 124 psi 5.88 mgd Feed 112 psi 95 psi 011mgd mgd 1 mgd 0.23 mgd 149 psi 102 psi 2.7 mgd 1.12 mgd 0.88 mgd 73 psi 82 psi Energy recovery device w/motor Concentrate Fluxes 17.2 gfd 8.7 gfd 1.7 gfd 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

8 IMPROVED OPERATION ACCESS IN NEW RO BUILDING 8

9 ALTERNATIVE POST TREATMENT TARGET TO 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

10 LIME SYSTEM IMPROVEMENTS ExistingLimeSlurry System Existing system is a flow paced system that is ramped up and down based on 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 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

11 PHOTOS OF RDP SLAKING SYSTEM PILOT TEST Lime Slaker Tank Lime Slurry Aging gtank Slurry Transfer and Feed Pump Lime Slurry Feed Assembly 11

12 CONSTRUCTION PHOTOS 12

13 CONSTRUCTION PHOTOS 13

14