WASTE ORIGIN:General Production Processes
Process Immersion Chemical Baths and Spray-Rinse Cabinets
WASTE TYPE: Excessive Water Consumption

WATER REDUCTION AND RECYCLING OPTIONS: Process or Equipment Modification

• Develop a cleanliness standard for printed circuit boards at every process stage to determine the minimum amount of water required for product quality.
• Observe and record production processes to estimate water use and pressure. Inspect
• tanks, enclosed cabinet chambers, pumps, pipes, spray nozzles, sumps, and photosensors for operating deficiencies.
• Establish the lowest water flow rate that produces acceptable results for parallel process lines (produce identical products using identical processes).
• Monitor flow rates of water supply lines for each process: install additional flow gauges throughout the plant to easily quantify flow-rate reductions and calculate water and cost savings.
• Maintain and optimize the use of photosensors to restrict water flow rates by:
  • Installing photosensors in spray-rinse chambers where they do not exist;
  • Repairing or replacing defective photosensors;
  • Performing routine maintenance (clean and readjust) to keep photosensors working properly.
• Maintain and optimize plumbing and other equipment used for directing water flow through the production facility:
  • Eliminate hoses that supplement supply water to spray rinses;
  • Hard plumb all water-bearing supply pipes;
  • Improve water movement in spray cabinets sumps and immersion baths to maximize water rinsing capabilities;
  • Recirculate fresh water rinse to an earlier rinsing stage using a counterflow method, or reuse it as makeup water for process bath or spray solutions.
• Consider other water conservation methods including:
  • Flow restrictors on flowing rinses;
  • Counter-current rinsing or cascade rinsing systems;
  • Redesign rinsing tanks for more efficient water use;
  • Fog rinsing;
  • Reactive rinsing;
  • Rinsing with purified or softened water;
  • Dead rinses;
  • Conductivity controllers;
  • Agitation to assure adequate rinsing and homogeneity in rinse tank;
  • Flow control valves;
  • Air knives to reduce dragout.

Sources

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