Improved Waste Stream Processing Is a Pathway to Savings and Compliance – Production Machining

In metalworking, addressing two specific aspects of waste stream management—wastewater and spent cutting fluids—can help companies not only meet environmental compliance, but also reduce expenses.

To mitigate wastewater liabilities, several processes can be used—often in combination—to lower financial risk and achieve zero liquid discharge goals. Ultrafiltration, for example, produces a consistent and quality effluent by separating organics, emulsified oils and suspended solids from wastewater. This enables the treated water to be reused or disposed of.

Another key process, tramp oil separation, removes free-floating and mechanically dispersed tramp oils, bacteria, slime and inverted emulsions. These contaminants are often found in machining and grinding fluids, wash waters, cooling water and wastewater.

Reverse osmosis is often used as a secondary treatment after ultrafiltration to remove dissolved salts, as well as colloidal and suspended matter. The concentrate can be either sent to the Publicly Owned Treatment Works or processed more on-site to reduce the wastewater volume further.

Vacuum filtration and vacuum evaporation are also used in certain wastewater applications. Vacuum filtration eliminates high contamination levels by removing fine particulate and collecting solids and sludge. Vacuum evaporation significantly reduces process water and wastewater volumes. The distillate produced from vacuum evaporation can be reused in the process, while the concentrated waste can be hauled away.

Two popular methods for lowering hazardous waste liabilities associated with cutting fluids are wringing chips and recycling the coolant. During wringing, centrifugal force spins metal chips and drains cutting fluids for reclamation.

A centralized coolant recycling system takes that one step further by removing tramp oils and suspended solids from contaminated fluids. This process controls bacteria to extend coolant life so that it may be reused significantly. For example, PRAB, Inc. ?Guardian systems can also adjust fluid concentration. Because the cutting fluid is being recycled and reused, hazardous waste storage, haul-away liabilities and disposal costs will all be lower.

Stricter environmental regulations are inevitable, but that doesn’t automatically mean that environmental compliance has to be a drain on the operation. With the assistance of a total solutions provider of process water, wastewater and fluid management equipment, metalworking companies can not only reduce their liability risk, but they can also lower their operating expenses. In this way, environmental compliance is a pathway to cost optimization as much as it is a regulatory responsibility.