240 likes | 284 Views
Reuse of Wastewater - A Manufacturer’s Experience. Steve Pierett, Env.Mgr . CEM, CRM, CP EnMS -Industrial. Volvo Group North America, LLC. New River Valley Plant, Dublin, VA. Area’s Largest Manufacturing Facility Largest Mfg. Facility in Volvo Family. Outline. Drivers and Incentives
E N D
Reuse of Wastewater - A Manufacturer’s Experience Steve Pierett, Env.Mgr. CEM, CRM, CP EnMS-Industrial Volvo Group North America, LLC
New River Valley Plant, Dublin, VA Area’s Largest Manufacturing Facility Largest Mfg. Facility in Volvo Family
Outline • Drivers and Incentives • WWTP Discharge Evaluation • Selected Treatment Method • Wastewater Reuse Points • Pros and Cons of Process Use Point • Continual Improvement • Overall Benefits
Wastewater Reuse Drivers Environmental Issues • Surfactant issues at the regional authority / foaming • Molybdenum contamination of land-applied sludge • Volvo is proactive to identify its contribution to a potential issue Volvo Environmental Requirements • Wanted Position: To install water recycling processes with low water usage and preferably with chemical recycling in closed loop processes
Wastewater Reuse Incentives Environmental Sustainability • Volvo is reusing up to 8.4M gal/yr of process water • Annual reuse rate is 60 to 80% for process water Reduction in Purchase of Water • Plantwide use of 62 Mgal in 2003 to 26 Mgal in 2012 • Since 2003, 57.6% Reduction in plant water use • Volvo is saving a projected $90,000 in the purchase of water and the disposal of water.
Wastewater Reuse Incentives Environmental Liability / Risk Mgmt. • Quality of feed water to industrial processes will reduce the need for chemical treatment and increase cooling efficiency and equipment life. • Direct capital funds to recycle water instead of meeting increasingly stringent environmental regulations. Process Improvements
WWTP Discharge Evaluation Criteria • Average daily flow from WWTP • 36,307 gallons per day • Maximum treated flow (WWT) = 500 gpm • Storage capacity of untreated wastewater • 240,000 Gallons • Conventional precipitation system. Treats Nickel and Zinc (0.099 mg/L limit for Ni and 0.6 mg/l limit for Zn) • Details presented at AWMA conference in June 2006 Tracking Number: 06-A-28-AWMA
Technologies Evaluated • Distillation / Evaporation • Ion Exchange • Membrane Filtration with Ultra-Filtration and High Pressure Reverse Osmosis System
Selected Treatment Technology Membrane Filtration (UF with HPRO) - Produces acceptable process water with little organic, microbiological or inorganic contamination. - Minimal operating labor required (automatic operation did not require additional labor) - Waste is simple to treat (concentrate streams treatable with conventional precipitation system) • Low Capital Cost of system and low overall operational cost
Treatment Method The reuse system consists of the following components: Ultra-Filtration UV Light UF Feed Storage WWT Cartridge Filter UV Light Waste Water Storage Untreated Wastewater To Plant Processes Reuse Water Storage HPRO Feed Storage UV Light High Pressure Reverse Osmosis
Design Specifications and Installation Cartridge Filtration Ultraviolet Light (254nm)
Design Specifications and Installation Ultra-Filtration High Pressure RO
Initial Usage Points – Focus on Non Process Opportunities • Paint Booth Water: 15,000 gpd • Humidification: 12,000 to 18,000 gpd • Parts Wash: 12,000 gpd • Cooling Tower: 4,000 to 6,000 gpd
Current Usage Points – New Focus on Process Opportunity • E-coat high-purity water (HPW) system required replacement • Ran 3-4 months of water testing to baseline system to verify performance before incorporating process needs • Advantage: • Avoid capital expense and incorporated e-coat into reuse system instead • Disadvantages: • Drives reuse water requirement to lower conductivity • More frequent discharge events due to higher water quality requirements.
Current Use Points • PROCESS • E-coat System: 15,000 to 20,000 gpd • NON-PROCESS • Humidification: 500 to 1,000 gpd • Parts Wash: 12,000 gpd • Cooling Tower: 4,000 to 6,000 gpd
Pros and Cons with Process Use • Advantages • Improved consistency and demand of reuse • System easier to manage • Eliminated auxiliary RO system for E-coat • Less cost / salt / energy / capital investment / labor • With e-coat demand, less water loss during shutdown • Disadvantages • Lower conductivity required to support E-coat process • Increased frequency of discharges to regional authority • At lower end of reuse performance over time • Increased need for more storage capacity
Process Improvement - 2014 • Install solids removal methods for E-coat discharge to reduce impact of process on conductivity/TDS & TSS.
Process Improvement - 2014 • Expand the storage capacity for reuse water to address losses associated with shutdown periods by addition of two 17,000 gallon pure water storage tanks. • Eliminate Stormwater influent to WWTP causing reduced WW reuse efficiency
Process Improvement - 2014 • High pressure RO system will address lower conductivity requirement for E-coat, but allow improved system reuse (provide greater than 90% recovery of process waters)
Overall Benefits • Low operating costs • Improved feed water quality • Reduce environmental liability and risk • Reduced chemical usage • Decrease in water purchase and disposal costs • Major step towards fulfilling Volvo Wanted Environmental Position
Steve Pierett, C.E.M., Environmental Manager Volvo Group North America, LLC 540-674-7730 stephen.pierett@volvo.com Brian Kidd, Principal ProChem, Inc. 540-268-9884 bkidd@prochemwater.com