| Metal Recovery at Howard H. Sweet and Son, Inc. | United States | 1989 | Full scale |
MANUFACTURE OF FURNITURE; MANUFACTURING N.E.C. # 12
Background
Howard H. Sweet and Son in Massasuchetts, United States, is a l25-worker jewelry manufacturer specializing in the production of silver, gold and gold-filled beads, chains and findings. The company's operations are widely integrated, spanning from the design and manufacture of the working parts for its own chain-making machines, to the stamping of flat stock and tubing, to bead and chain making, to the soldering, plating and assembly of finished jewelry.
In late 1985, Howard Sweet was faced with new regulations requiring it to implement further pollution controls. The company determined that a major source of hazardous waste was its burn-out room - where copper used in the fabrication of gold beads is stripped away. Faced with this requirement to implement new pollution controls, the company first examined traditional wastewater treatment options. Problems of space and cost immediately became apparent.The company then looked at the cost, space requirements and compliance reliability of equipment offered by ACCA Technologies Corporation of Plainville, Massachusetts. With the ACCA Technologies equipment, Sweet found that it could meet its wastewater discharge limits in a cost-effective way.
Cleaner Production Principle
Recovery, Reuse and Recycle; New technology
Cleaner Production Application
Howard Sweet chose to invest in the ACCA system, which amounts to a virtually closed-loop recovery system for copper and gold. The company asked the Office of Safe Waste Management (renamed the Office of Technical Assistance in 1989) to conduct a source reduction inventory at its facility on Walton Street in Attleboro, Massachusetts. The Office of Safe Waste Management analyzed the company's production processes and management practices, then offered suggestions for reducing the generation of manufacturing byproducts. It recommended that the company evaluate in-house methods of recovering nickel and rhodium, and that it investigate gold bath management techniques which offer the potential for enhancing the efficiency of metals recovery and increasing the value of recovered metals. In addition, the Office of Safe Waste Management suggested several techniques for improving solvents management to reduce solvent use and conserve water. If implemented, these recommendations could lead to cost savings as well as to reductions in waste generation.
Environmental and Economic Benefits
The capital and engineering costs for the ACCA Technologies system totaled $95,000. Income from the recovery of additional gold and copper covered these up-front costs in 12.6 months. After the first year, the company expects its new system to return over $95,000 in recovered metal annually, while doing away entirely with its need to pay for sludge disposal.
The true savings realized by the investment are best assessed by comparing it to the traditional pollution treatment system that Sweet would have had to invest in if it had not opted for metals recovery. The following chart offers such a comparison.
The costs of Treatment vs. the Costs of Recovery:
| Cost Categories | Wastewater Treatment | ACCA Technologies |
| Capital Cost | $200,000 | $65,000 |
| Engineering | (included) | $30,000 |
| Expenses | ||
| Labor | $37,500 | $ 7,500 |
| O&M | $52,500 | $10,500 |
| Disposal/Sale of Gold | ($40,000)* | ($107,200)** |
| Disposal/Sale of Copper | $ 1,350*** | ($879)**** |
| Total First Year Cost | $251,350 | $4,921 |
| Annual Operating Cost | $51,350 | ($90,079) |
| Payback Period | None | 12.6 months |
- * Assumes recovery of 100 oz. of gold at $400/oz., as per pre-existing recovery system.
- ** Actual gold recovery with ACCA system was 268 oz. per year.
- *** Assumes that disposal facility takes 18,000# of copper sludge at $0.60/gallon.
- **** Actual copper recovery was 2144# per year, sold at $0.40/#.
During the first year of operation, Sweet's new system recovered 263 troy ounces of gold and 2,144 pounds, or more than one ton, of copper. At the same time, the company entirely eliminated its generation of toxic sludge, thus lowering its disposal costs.
Constraints
None reported.
Contacts
Review Status
This case study was received by the Office of Technical Assistance of the State of Massachusetts in the United States. It was edited for the ICPIC diskette in May 1997.
Subsequently the case study has undergone a technical review by Dr Prasad Modak at Environmental Management Centre, Mumbai, India, in September 1998.