# Presentation: 214581

## Instrumentation Division Printed Circuit Board Process Assessment and P2

*Melvin Van Essendelft*
*Environmental Compliance Representative*
*August 19 & 20, 2008*

- A circular circuit board made for the silicon
- vertex telescope at the NA45 experiment at
- CERN. The board houses 24 monolithic circuits
- that amplifies the signals from the silicon detector
- mounted in the center.

## Basic Process Assessment Steps

- Ron and Howard inspect a sheet of core material to
- be laminated into a multi-layer printed circuit board.

## Process Flow Diagram Detail

## P2 Evaluation In Process Assessments

| Pollution Prevention Opportunities |  |  |
| --- | --- | --- |
| Waste Stream ID | P2 Opportunity | Resolution |
| 2.1.1, 2.4.1, 2.6.1, 2.8.1, 2.9.1, 2.11.1, 2.12.1, 2.16.1, 2.20.1, 4.1.1, 4.8.1, 4.11.1, 7.2.1, 7.3.1, 9.10.1. | These corrosive waste streams could be managed as industrial waste instead of hazardous waste if they were neutralized. | These waste streams are hazardous waste due to corrosivity only, and do not contain listed waste.  If neutralized, these baths could be managed as industrial waste, or possibly be sewer disposable.  However, the time and effort required to neutralize these baths would not be an efficient use of resources.  Neutralization can be considered in the future if a reduction of the hazardous waste stream produced from this process is desired. |
| 3.8.3 | Untreated Spent Developer Solution: 
Currently being  treated and discharged to sanitary as approved (Attachment 2).Spent developer is acidified with H2SO4, polymer precipitates out and is removed and disposed in trash, solution then neutralized (contains no metals) and is discharged to sanitary waste, as approved.. | Not being performed due to concern that poly film will clog pipes. |
| 6.4.1, 6.4.2, 6.4.3 | Evaluate use of water based solder mask and legend ink to reduce solvent use/emissions | TBD |

## Assessment, Prevention and Control Measures

| Assessment, Prevention and Control Initiatives |  |
| --- | --- |
| Waste Stream ID | SOP, Inspection or other APC Measures Recommended |
| All liquid waste streams sent to WM | If the pH of a spent bath, which is sent to WM for disposal, is 2, or 12.5, then the bath shall be labeled as a hazardous waste and the pH noted on the waste control form.  The bath would be a hazardous waste because it exhibits the characteristic of corrosivity.
If the pH of a spent bath is between the range of 2 and 12.5, it should be labeled as non-hazardous waste and the pH noted on the waste control form.  This bath would be considered an industrial waste.
The pHs of the waste baths have been noted on this PAF, along with the type of waste generated.  However, the pHs may vary somewhat in practice.  If the pH of a bath is in question, or is close to one of the pH limits, it shall be measured prior to disposal to correctly characterize the waste. |

## PC Board Pollution Prevention Initiatives

**Elimination of Lead in printed circuit board fabrication**
**Routine chemistry analysis to reduce the change-out of plating baths**
**Solvent-free aqueous coatings other than solder mask & legend screening**
**Installation of a closed loop ion exchange recycle system in the printed circuit board shop, to eliminate a source of copper to the STP** (Planned)

## Lead Free P.C. Board Fabrication

- Elimination of lead and minimization of wastes in the following process steps:
- Solder Plating Bath
- Anode filter bags, cartridge filters
- Anodes
- Waste-water
- Resist striper bath
- Etch Process
- Etchant
- Filter cleaning waste
- Waste-water
- Solder reflow
- Brushes, lead contaminated debris
- Solder & flux air emissions
- Waste-water
- Final Fabrication
- Routing dust
- Scrap boards

## Closed Loop Ion Exchange System P2 Benefits

- Eliminate wastewater containing copper to the Sewage Treatment Plant
- Potentially eliminate SPDES violations at the Sewage Treatment Plant
- Eliminate photographic rinse water effluent
- Reduce Instrumentation Division water consumption by 15,000 gallons per month

## Closed Loop Ion Exchange System ROI

- Total Project Cost: $49,750.00
- Annual Cost Savings: $25,000.00
- Payback Period: 2 years

## Waste Minimization of P2 Initiatives

| FY | Boards (FT2) Processed | Haz. Waste Generated (lbs.) | Haz. lbs./ft2 | Recycled Spent Etchant (lbs.) | Total lbs./ft2 |
| --- | --- | --- | --- | --- | --- |
| 00 | 1,177 | 3660 | 3.11 | 0 | 3.11 |
| 01 | 1,046 | 4240 | 4.05 | 0 | 4.05 |
| 02 | 1,050 | 3200 | 3.04 | 450 Shipped | 3.47 |
| 03 | 738 | 80 | 0.11 | 800 Shipped | 1.19 |
| 04 | 700 | 540 | 0.77 | 20 (Accumulated) | 0.80 |
| 05 | 950 | 40 | 0.042 | 550* | 0.62 |
| 06 | 988 | 80 | 0.081 | N/A | 0.81 |

- 	* One industrial drum of waste due to tank clean-out (~ every 3 years)