3/25/2015. MARCH 24, 2015 Chad T. Olsen, P.E., BCEE. WRWA 27 th ANNUAL TECHNICAL CONFERENCE. City of Chilton, Wisconsin. Chilton.

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1 MARCH 24, 2015 Chad T. Olsen, P.E., BCEE City of Chilton, Wisconsin Chilton Chilton 1

2 City of Chilton Population - 3,800 Major Industries Briess Malt & Ingredients Company (2 Plants) Worthington Cylinders Chilton WWTF discharges to South Branch of Manitowoc River Chloride criteria for River is 400 mg/l WPDES permit includes a Variance raising limit to 1,025 mg/l Permit includes a target value of 755 mg/l City will eventually have to meet the 400 mg/l criteria. Chilton Water System Municipal Water from 3 wells Well #7 675 gpm Well #9 400 gpm Well # gpm Ave Water Hardness = 462 mg/l as CaCO 3 or 27 grains/gal Considered Very Hard Water Can Form Scale in Water Heaters, Pipes, Appliances, etc. Causes staining Increases Soap Consumption City Municipally Softens all Water provided to customers All Water treated/softened at Pumphouse #8 Ion Exchange Softeners 2

3 Ion-Exchange Softening Softening Cycle WRWA 27 th ANNUAL TECHNICAL CONFERENCT WATER SOFTENER WATER CONTAINING HARDNESS MANY GALLONS LATER CAPACITY TO SOFTEN HARD WATER NOW ENDING With sodium charged exchanger material Completely softened water containing sodium in exchange for hardness Water softener still delivering completely softened water Regeneration with salt brine now necessary to recharge exchanger material with sodium WASTE WATER CONTAINING HARDNESS IN EXCHANGE FOR SODIUM WRWA 27 th ANNUAL TECHNICAL CONFERENCT Ion-Exchange Softening Regeneration Cycle WATER SOFTENER STILL DISCHARGING WASTE WATER CONTAINING HARDNESS EXCESS SALT BRINE ALSO REMOVED WATER SOFTENER 5 Salt brine 6 15 to 20 minutes later 7 Regeneration almost complete 8 Exchanger material again ready to exchange sodium for hardness and to continue to deliver completely softened water 3

4 DISTRIBUTION SYSTEM 3/25/2015 PUMPHOUSE #8 TREATMENT FACILITY BYPASS 500,000 GAL GROUND STORAGE BOOSTER PUMPS 1500 GPM 1500 GPM SOFTENERS WELL #9 400 GPM WELL # GPM WELL #7 675 GPM ELEVATED STORAGE Existing Water System Schematic TANK 2 BREED STREET 200,000 GAL TANK 3 SOUTHSIDE 300,000 GAL FUTURE DESIGN DEMAND 1.7 MGD MAX DAY Pumphouse #8 Plan 4

5 RAW WATER 1200 gpm 27 Grains/Gal 2008 Softener Operation SHELL #1 SHELL #2 SHELL #3 FM BYPASS 2008 Operation Shells regenerate after 260,000 gals Theoretical capacity 209,000 gals 108 gpm Theoretical to achieve 7 grains : 311gpm City use both Bypass & Overrun Softener to achieve 7 grains SOFT WATER 1200 gpm 7 Grains/Gal 5

6 Existing Softening Facility at Pumphouse #8 Number 3 Diameter (feet) 10 Resin Depth (feet) 3.5 Resin Volume, each (cu.ft.) (initial) 282 Resin Type Duolite C-20 Resin Capacity (grains/cu.ft.) 20,000 Hardness Removal Capacity, each (grains/cycle) 5,640,000 6

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9 Water Supply Characteristics WELL #7 WELL #9 WELL #10 Capacity (gpm) Ca, as CaCO 3 (mg/l) Mg, as CaCO 3 (mg/l) Total Hardness, as CaCO 3 (mg/l) Hardness (grains per gallon) Chloride (mg/l) Combined Iron 0.1 mg/l Water Softening System Evaluation Chilton Municipally Softens Water Sent to the Distribution System Target water hardness = 7 grains/gal Two Issues Prompted Water Softening System Evaluation in 2008 Capacity Concerns with Growing Water Demand Chloride Concerns at WWTF Salt (sodium chloride) used to regenerate softeners Wastewater from regen process contributes to chlorides at WWTF City granted a variance with an interim limit of 1,025 mg/l Water quality standard = 400 mg/l City will have to eventually meet the Water Quality Standard 9

10 Gallons Sold 3/25/2015 Pumphouse Capacity Concerns During High Demand Periods Treated water production could not keep up with demand Reservoir level at the Pumphouse would drop Industrial water demands projected to increase The following contributed to dropping reservoir levels High Lift Pumps deliver 1,500 gpm while softeners produce about 1,200 gpm Softeners were backwashed/regenerated with raw water Water Usage of Major Industrial Customers 80,000,000 70,000,000 Briess - Irish Rd. Briess - Malt House Worthington Total Sales (Number is % of Total Sales) 60,000,000 50,000, ,000,000 30,000,000 20,000, ,000,000 0 Quarter Ending Date 10

11 Raw Water Regeneration/Backwash Softener regeneration can only occur when well is in operation Controls operate wells to maintain a reservoir level of 10.4 to 14 ft At a level of 12 ft, regeneration not allowed to prevent reservoir overflow The limited range to regeneration ( ft) causes regenerations to stack-up During peak days, can have back-to-back regens once level drops below 12 ft During brine/slow rinse cycle (54 mins), flow to pumphouse reduced to 750 gpm vs gpm with all 3 shells Maintain flow of 350 gpm to each operating shell. Existing Softener Salt Use Efficiency Softeners were designed per WI NR 811 requirements Resin Capacity of 20,000 grains/cu.ft. of resin Salt rate of 3,333 grains removed per lb/salt Results in 6 lbs of salt per cu. ft. of resin Resin performance typically degrades with time due to fouling, loss of resin or deterioration Ave Salt use efficiencies ,286 grains/lb salt ,834 grains/lb salt ,511 grains/lb salt Average 3,200 grains rem per lb of salt Minimal degradation over time (original to 1979) Little room for improvement 11

12 City of Chilton Blended Effluent REGENERATION WASTEWATER WASTEWATER TREATMENT FACILITY PUMPHOUSE #8 LIFT STATION FM WWTF EFFLUENT BLENDED DISCHARGE Wastewater Treatment Facility Effluent Chlorides Limit for WWTF would be 400 mg/l City given variance cannot meet limit Variance requires City to reduce chloride levels Chlorides pass through WWTF not removed through treatment Pumphouse Regen wastewater blended with effluent from WWTF at outfall Salt Used for Regen 3,992 lbs/day 4,618 lbs/day 4,000 lbs/day Chlorides from Regen 2,421 lbs/day 2,801 lbs/day 2,427 lbs/day Chlorides at WWTF outfall 3,964 lbs/day 5,016 lbs/day 3,940 lbs/day % Chlorides from Softening 61% 56% 62% Combined chloride conc at outfall 599 mg/l 658 mg/l 546 mg/l 12

13 Pumphouse #8 Improvements Improvements made in 2010 to increase capacity and reduce chloride discharges Replace existing resin with salt saving resin Increase softener bypass capacity Utilize system water for softener regeneration Modify controls Salt Saving Resin Existing Resin replaced with salt saving resin Shallow Shell Technology (SST) resin from Purolite Direct replacement of existing resin SST Resin has an inert center Inert center limits the penetration of hardness molecule into resin bead Reduces amount of regenerate (brine) required to regenerate bead Less driving force required to remove captured hardness molecules Resin also less susceptible to iron fouling 13

14 Salt Saving Resin SST Resin has an inert center SST resin has a more complete regeneration less hardness leakage SST resin also requires less fast rinse water Fast rinse time reduced from 10 mins to 5 mins Inert center has minor impact on capacity 95% of resins reactive sites are contained in 60% of resin depth Volume Ratio s r SST Resin Inert Core, Functionalized Shell where: s/r = shell radius Standard Resin Fully Functionalized Shell Radius Volume ratio 78.4% 87.5% 93.6% 97.3% 98.7% 99.9% 100% 14

15 SST Resin (Shallow Shell Technology) Standard Resin SST Resin

16 SST Resin in Chilton Conventional Resin (prior to upgrade) Capacity at a Salting Rate of 6 lbs/cu.ft Results in 20,000 grains removed/cu.ft. of resin 3,333 grains removed per lb salt SST Resin allows for lower Salting Rates City of Chilton set up for 3.5 lbs/cu.ft. Resin capacity = 17,000 grains removed /cu.ft. of resin Resultant efficiency 4,800 grains/removed per lb of salt 44% increase in efficiency 16

17 SUE, Grains Hardness Removed/lb Salt 3/25/2015 Resin lbs/nacl/cf ,000 City Of Chilton Monthly Average Salt Use Efficiency August December ,000 4,000 3,000 2,000 1,000 0 Date Salt Use Efficiency lbs salt Conventional Resin 17

18 Benefits of SST Resin for Chilton SST Resin Saves on Salt Use Salt Use with SST 3,059 lbs/day 2,885 lb/day 2,917 lb/day Projected Salt use with past Resin 4,558 lb/day 4,299 lb/day 4,346 lb/day Salt Reduction 1,499 lb/day 1,414 lb/day 1,429 lb/day Savings at $90 per ton $24,600 $23,200 $23,500 SST Resin Reduces Chloride Discharges lbs/day lbs/day lbs/day At an avg WWTF, flow of 0.8 MGD = 130 mg/l reduction in chlorides SST Resin Reduces Final Rinse Water Final Rinse reduced from 10 mins to 5 mins Saves 2,000 gallons of water per Regen SST Resin does Require More Frequent Regenerations Conventional Resin at salt rate of 6 lbs/cu.ft. 20,000 grains/cu.ft. SST Resin at salt rate of 3.5 lbs/cu.ft. - 17,000 grains/cu.ft. Capacity of each shell at raw water hardness = 27 grains Conventional 208,890 gals SST Resin 177,560 gals At an average water demand of 700,000 gallons Conventional 2.5 regens/day SST Resin 2.9 regens/day Regeneration Water Demands at water demand of 700,000 gpd Conventional - 26,888 gpd SST Resin 22,640 gpd 18

19 chlorides, lbs/day chlorides, mg/l water demand, gpd water demand, gpd 3/25/ Average WWTF Chloride Concentration , , , , , , , , ,000 0 Ave Chloride Concentration Ave Water Demand 5,300 Average WWTF Chloride Loading 900,000 4,800 4,300 3,800 3,300 2,800 2,300 1,800 1, , , , , , , , , Ave Chloride Loading Ave Water Demand 19

20 Other Improvements Made at Pumphouse System Water Regeneration Softener Regenerations no longer dependent on Reservoir Level Softener Regens no longer stack-up during high demand periods Installed new flowmeter and automated valve to control softener bypass flow rate Previous Bypass Flow rate 108 gpm New Bypass Flow 300 gpm Other Improvements Made at Pumphouse New Softener Controls Antiquated controls replaced Each softener received a new stager panel New PLC controls for overall control New Brine Pumps New pumps needed due to lower brine flows Pumps are magnetically driven (no seals) New Brine Dilution System Improved control of brine feed Allows for optimized brine concentration to softeners 20

21 Capacity Increase with Improvements Existing softening facility had a maximum capacity of 1.45 MGD Capacity increased to 1.58 MGD Throughput through two operating softeners increased from 350 gpm to 413 gpm/shell when a softener is regenerated With bypass, this provides a full-flow capacity of 1,100 gpm at all times Facility has a maximum capacity to produce up to 2.6 MGD Limited by Water Supply Chilton currently installing Well #11 Pumphouse Construction Construction started Spring, 2010 Softening System was out of service for approx. 4 weeks Construction did have its hiccups At softener set-up, backwash valve not set correctly Backwash flow should be 400 gpm Initial backwash flow considerably over 400 gpm Caused bed to expand beyond upper header - resin loss to drain Also noticed resin in finish water reservoir Underdrain nozzles broke Had to empty all three beds a second time and install new nozzles May have been caused by high backwash flow 21

22 Typical Softener Shell Raw Water In / Backwash Out Upper Header Brine Brine Header Resin Soft Water / Backwash In Underdrain Gravel Bed Resin Delivery 22

23 Existing Brine Header Existing Resin Vacuuming out Existing Resin 23

24 Existing Underdrain New Brine Header 24

25 Softener Supply Backwash Return Header New Brine Header New Resin in Softener 25

26 Broken Underdrain Nozzle New Digital Stager Controller 26

27 New Brine Pumps New Brine System 27

28 Acknowledgements City of Chilton Todd Schwarz Chris Marx Mike Gudex Dept. of Public Works Q A 28