When possible, coolant channels in the machines should be covered or screened to minimize contamination from dirt and dust, floor sweepings and metal chips. Coolant filters should be regularly cleaned or replaced. Blind spots that allow chip accumulation and bacterial growth should be cleaned out and sealed. Coolant life may be extended and waste generation reduced if these practices are followed. Tap water contains dissolved ions such as calcium, magnesium, and sodium carbonates and sulfates which can affect coolant quality and bacterial growth.
Sulfates act as oxygen sources for sulfate-reducing bacteria.
Coolant life may be extended and work quality is improved by substituting demineralized water in place of tap water which can reduce coolant consumption by 30 to 40 percent. There are a wide variety of recycling techniques available for on-site coolant recycling. They include skimming, vacuum and pressure filtration, centrifugation, pasteurization, ozone injection, UV irradiation and chemical sterilization. An effective recycling system will typically employ two or more of these techniques in order to remove the different types of contaminants present. Standardization of the coolants should be considered in order to promote recycling which can actually reduce material and administrative costs and waste management expenses as well.