MlTSUBlSHl SEMICONDUCTOR AMERICA, INC. Three Diamond Lane. Durham, North Carolina (919) FAX(

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1 4' r\f (b 9 A < 7 MlTSUBlSHl SEMCONDUCTOR AMERCA, NC. Three Diamond Lane. Durham, North Carolina (919) FAX( "0!J F APPLCATON FOR EPA REGON V 1993 MSJMCPAL WATER USE EFFCENCY AWARDS Contact: Ronald P. Srebro - Senior Chemical Engineer Facility Engineering Dept. Phone: (919) Fa: (919)

2 (,. < S. 3 &a MTSUBSH SEMCONDUCTOR AMERCA, NC. Three Diamond Lane. Durham, North Carolina (919) FAX( PROJECT DESCRPTON Mitsubishi Semiconductor America, nc. (MSA), located in Durham, NC, is a leading manufacturer of high quality integrated circuits. n and- 1992, MSA implemented several projects aimed at conserving resources and reducing waste management costs. The semiconductor industry is a very water-intensive industry with very stringent water quality specifications. MSA has instituted four major projects to conserve this precious resource and to reduce wastewater production. Collectively, these four projects reduced water usage fiom million gallons in April 1991 to 4.2 million gallons in April All of these systems were designed with instrumentation that ensures that water quality specifications are met at all times. One of these projects was to decrease water usage and wastewater generated by the wet benches. This goal was accomplished by (1) installing timers to automatically shut off water flow to the benches and (2) using resistivity meters to divert reusable water for recycling. A second project was to recycle rinse water from the deionization column regeneration process back to the columns whenever the rinse water reaches a specified resistivity. n 1992, MSA also implemented two major projects to recycle industrial wastewater for use as high purity water make-up. Prior to initiating these projects, pilot studies were conducted to determine the projects' feasibility and to refine design parameters. MSA has two wastewater pretreatment plants. One neutralizes acidalkali rinse water; the other processes fluoride rinse water and, thereby, generates a calcium fluoride/ aluminum fluoride sludge. One of the recycle projects involves deionizing the neutralized acidalkali wastewater; the treated stream is then used as high purity water make-up. The deionization system consist of a sand filter, 1-pm cartridge filters, a carbon bed, ultraviolet light sterilization, followed by a 40 f? cation bed and a 40 f? anion bed (see Figures 1 and 2). The second water recycle project uses reverse osmosis to clean the untreated fluoride wastewater stream. The reverse osmosis system consist of two tanks for ph adjustment, a holding tank, booster pumps, 1-pm bag filters, a 200 gpm pump, a reverse osmosis skid, an ultraviolet light sterilizer, and two 40 fl? anion beds. The system operates at 85% recovery. The permeate is then deionized and sent to high purity water make-up. The reject water is sent to the fluoride wastewater treatment plant. (See Figures 3,4, and 5.)..) Additionally, MSA uses neutralized wastewater in a MSA-designed bottle washer to clean empty glass and plastic bottles for recycling. Also, the plant was originally designed to, and

3 continues to use, concentrated reject water fiom the high purity water reverse osmosis system for cooling tower make-up. MSA management encourages all employees to take an active part in resource conservation and waste reduction through an employee suggestion program. Employee awareness of water conservation is enhanced through prominent graphical display of monthly water usage and costs. MSA has worked with the City of Durham's Water Conservation Department to share our success with these water recycling programs and to evaluate potential application to other industries in the area. The success of these programs can be attributed to MSA's commitment to being a good neighbor environmentally, employee awareness of water consumption, and an aggressive industrial planning department that provided unbudgeted funding for these projects that were designed and built by the MSA facility engineering department.

4 ,, ' SEQUENCE OF OPERATON WATER RECYCLE (ACD ALKAL SYSTEM1 TANK 7 0 MEASURE PH 6 TDS F GOOD T F LTER - 1 MCRON CARTR DGE FLTER P- b- 1 $ CARBON p r. 4 ULTRAVOLE (X CAT ON F NOT GOOD BED ii F NOT GOOD 0 TANK 50 MAKE -UP FGURE 1

5 b i PROCESS & NSTRUMENTF NO SCALE c LEGEND VA = ACTUATED VALVE VM = MANUAL VALVE VC = CHECK VALVE c1 = CONDUCTVTY METER #? ~2 = CCMUCTVTY METER #2 *. FGURE

6 , + \ t t m TW 61 t T-34A t T-63 1T ON D AGRAM ACD/ALKAL WATER RECYCLE wwr.dgn

7 -3 FLUORDE WASTE WATER RECYCLE SEQUENCE OF OPERATON Figure 3 Tank 66 f Bad Overflow To Tank 13 b Tank 67 Tank 68 Filter Pumps (Pump 68A & B) + 1 u Filter Housing Reverse Osmosis Unit ~ Flow 1 Flow ] Reject To Tank 13 1 u Filter + * Tank 69 T Tank 50 1 HPW Makeup

8 FROM TANK -- ff 12 OWLM m TANK 13 PROCESS & NU SCALE FLUORD FWR.DGN

9 STRUMENTATON DAGRAM WATER RECYCLE. -.-

10 i LJ WATER FLOW SCHEMATC FOR MSA t UTLTY BLOC HPY UNT HPW SYSTEM WAFER FAB -----c ULTRA - HPW SYSTEM FLTERS 1 TOWER MAKE-UP TANK BEFORE WATER -RECYCLE PROJECTS / T ACD WASTE-...._ AFTER WATER RECYCLE PROJECl L A C D WASTE G f\ - SANTARY SEWER * 1 TO CTY DATE: FGURE 5

11 -3 A MlTSUBlSHl SEMCONDUCTOR AMERCA, NC, Three Diamond Lane Durham, North Carolina (91 9) FAX( PRE-PROJECT CONDTONS Mitsubishi Semiconductor America, nc. has instituted four major projects aimed at reducing water usage and wastewater production. Before these projects were implemented all wastewater generated at MSA was treated at one of two wastewater treatment plants and discharged to the City of Durham's Eno River Treatment Plant. MSA has two wastewater pretreatment plants. One neutralizes up to 160 gpm of acidalkali rinse water using sodium hydroxide. The other treats up to 140 gpm of fluoride rinse water by precipitating a calcium fluoride/alu" fluoride sludge using calcium chloride, aluminum sulfate, and sodium hydroxide as treatment chemicals. (See Figures 6,7, and 8.) 1 n 199 1, prior to the implementation of any of these projects, the average city water usage at MSA was 10.9 million gallons per month, corresponding to an average monthly cost of $92,500. Because over 95% of the water used by MSA is not consumed by the manufacturing process or other processes, wastewater production corresponded to approximately 95% of water usage. The average cost to treat the wastewater generated was $60,000 per month. The amount of sludge landfilled per month was 78,000 pounds.

12 ACD/ALKAL TREATMENT SYSTEM Figure 6. NaOH Waste From A&T L Mix Concentrated And Dilute Process Waste Together n T-1 Concentrated Process Waste to T-2 (Slowly Pumped To T-1) + Equilization n T4 (ph Adjustment With HCL f Necessary, To Bring ph Below 7).pH Adjustment n T-5 With Caustic! 4 f ph Too High Or Too Low, Recycle By Pumping ph Adjustment n T-6 With Caustic 3

13 Concentrated Process - FLUORDE TREATMENT SYSTEM Figure 7 Slowly Pumped To T-1 1 H202 Waste Degased Batch Treated With CaC12. b Calcium Chloride Addition And Equilization n T-13A & B (ph Adjustment With HC or Caustic. f Necessary. To Adjust ph) Phase Gal. - Residence Time 100 Min. Phase Gal. Rasidence Time 180 Min. - Additional HC Pump With Logic (Overflow) ph Adjustment n T-15 With Caustic (Overflow) &. Solids Removal n High-Fluoride Clarifier Solids To Sludge Holding Tank C3A (Overflow) Alum Addition And ph Adjustment With Caustic n T-20 r (Overflow) Solids Removal n Low-Fluoride Clarifier Solids To Sludge Holding Tank C3A Too High Or Too Low, Or fluoride Too High. Recycle By Pumping (Overflow) 1 Check ph And Fluoride Level n T-22 1 (f ph And fluoride Ok) Phase 1 mproved nstrumentation Discharge To T-7 For Monitoring/Sampling

14 CaCS 0 w 0 a NUP\ E FeCS 0! v) i t TO CTY WASTE TREATMENT FLOW DAGRAM SCKE: NONE Figure 8

15 t. 1, 3 A MTSUBSH SEMCONDUCTOR AMERCA, NC. Three Diamond Lane Durham, North Carolina (919) FAX( POST-PROJECT CONDTONS Mitsubishi Semiconductor America, nc. (MSA) has instituted four major projects aimed at reducing water usage and wastewater production. These projects were implemented in two tiers. The wet bench timer/diverter and D regeneration rinse water reclamation were installed in late The wastewater recycle projects were started-up December 3 1, After the first two projects were implemented, the monthly water consumption was reduced from an average of 10.9 million gallons to an average of 8.6 million gallons. This corresponds to a reduction in water costs fkom $92,500 per month to $74,000 per month (see Figure 9). Since the start-up of the wastewater recycle projects the monthly water consumption has steadily decreased to a low of 4.2 million gallons in April 1993, corresponding to a monthly cost of $33,000. These savings are even more significant when they are coupled with the fact that production has increased nearly 30% since (A summary of the capital costs and overall savings for each project is presented in Table 1.) -1 Only 15% of the fluoride wastewater stream is now delivered to the fluoride treatment system. This reduction in flow, and corresponding increase in residence time, permits decreased requirements for treatment chemicals. This change has reduced consumption of calcium chloride by 35%, sodium hydroxide by 33%, and polymer by 50%. The average cost to treat the fluoride wastewater is projected to be $20,000 per month. The amount of sludge landfilled has also decreased by 3 1 %, compared to 1992 levels, to 42,000 pounds per month. Additionally, natural gas use has decreased by about 2000 decatherms per month. Natural gas is used to fire the boiler that heats high purity water to the desired temperature. Water that has been treated by the wastewater recycle system is the correct temperature. Therefore, only city water make-up has to be heated (see Figure 10). Another benefit is improved quality of the high purity water due to decreased conductivity (1 0 microsiemens for recycled water versus 200 microsiemens for city water). Total organic carbon (T.O.C.) concentration has also decreased from 40 ppb prior to initiating the recycle system to approximately 10 ppb now. This is important because total organic carbon, when oxidized in the process acid bath, produces particles that interfere with the wafer fabrication process. The quality of MSA discharge effluent to the City of Durham municipal wastewater treatment also has improved. Conductivity of the effluent has decreased fiom a range of microsiemens to a range of microsiemens. Currently, MSA is investigating the installation of cation beds in the wastewater reverse osmosis system. f the pilot studies indicate feasibility, this change will permit bypassing.'

16 the high purity water reverse osmosis unit, thus increasing recovery by 15%. MSA is also evaluating the possibility of recycling the discharge stream &om the fluoride wastewater treatment system using either 1 -pm spiral-wound filters or ionic filters.

17 FACLTY WATER USAGE 1991 vs 1992 vs 1993 v) c 0 13,000,000 12,000, ,oO0,000 1o,ooo,oO0 9,ooo,OOo P 8,000,000 c3 7,000,000 6,000,000 5,000,000 4,000,000 3,000,000 t JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC t Figure 9

18 Employee Awareness Program None Wet Bench Timer/Diverters 01 Regeneration Rinse Water Reclaim 8K 30K 222K. -1 Bottle Washer Acid/Alkali Waste Water Recycle 8K 338K 125K Fluoride Waste Water Recycle 800K 400K Table 1. Water Use Reduction Project with corresponding cost and annual savings.

19 c FACLTY NATURAL GAS USAGE 1991 vs 1992 vs ,000 7,000 6,OOo i 5,000 4,OOO 3,000 2,000 1,000 0 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 10

20 1 MlTSUBlSHl SEMCONDUCTOR AMERCA, NC. Three Diamond Lane Durham, North Carolina (919) FAX(919) MSA WATER REDUCTON WORK TEAM Pictured left to right: Kosei Matsuda (Facility Manager), Steve Elderkin (ndustrial Planning), Mike Rouleau (ndustrial Planning), Rich Still (Section Manager, ndustrial Planning), Melinda Jones (ndustrial Planning), Sam Haycraft (High Purity Water Technician), Tony Layton (Wastewater Technician), Ron Srebro (Chemical Engineer), Jake Gami (Section Manager, Facility Engineering) Not Pictured: Jennie Fick, Jeannine Frey (Facility Operators)

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Local Water Supply Planning - North Carolina Division of Water Resources

Local Water Supply Planning - North Carolina Division of Water Resources Montreat 2011 The Division of Water Resources (DWR) provides the data contained within this Local Water Supply Plan (LWSP) as a courtesy and service to our customers. DWR staff does not field verify data.