Pollution Prevention Opportunity

There are several steps that can be taken to reduce waste from solvent sink parts washers and save money.

Change the Solvent Less Often

If the solvent is still cleaning your parts well, do not change the solvent. Only replace the solvent when it no longer cleans. Run some tests and see how long the solvent will last. Some sinks may be used more than others. Also, periodically moving sinks from light to heavy wash loading areas will extend solvent life by sharing the cleaning load among all sinks.

Install Solvent Sinks with Filters

Many newer solvent sinks will filter solids as the pump recirculates the solvent. Instead of replacing the solvent, some companies have found that only the filter needs to be replaced to keep the solvent sink working.

If the solvent sink is leased, the supply company can often replace existing sinks with filter type sinks. If your company owns the sinks, consider purchasing new sinks with filters or refitting the existing sinks.

Use Solvent Sinks in Stages

If solvent sinks are used in pairs, the solvent will last longer. Use one sink as the first stage washer to wash very dirty parts. Use the second sink as the final stage washer.

The solvent in the first stage will become very dirty, but even dirty solvent will remove heavy grease and grime. The final stage wash sink will stay clean and will remove any grime left on the part after it has passed through the first stage.

When the solvent in the final stage washer gets too dirty for final cleaning, it can be replaced with clean solvent. The dirty solvent removed from the final washer can replace the solvent in the first stage sink. Only the very dirty solvent from the first stage sink is shipped offsite as waste. This type of cleaning is called two-stage washing. This process can reduce solvent usage and waste generation significantly.

Consider Solvent Alternatives

There are a number of cleaning chemicals that can replace hazardous or toxic solvents in solvent sinks. High flash point solvents are available that reduce hazardous waste generation. Water-based cleaners can also be used, eliminating hazardous waste and air emissions. Some water-based solvent sinks even use bacteria to eat oil and keep the cleaning solution clean. One company reported saving more than $60,000 annually be switching to water-based solvent sinks.

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