Oily Waste Water Minimization Techniques

Concerns over resource shortages, increased environmental awareness and a preoccupation with environmental issues as a public relations matter have led many companies and individual producers to examine the efficiency and environmental compliance of their industrial processes. As one of the major vectors for pollution, the production of waste has been the focus of many of these studies and initiatives. In the case of liquid wastes, such as oily water, the double problem of wasting a resource as vital as water and discharging harmful pollutants into the environment has led to several waste water minimization techniques.

Source Reduction

• By far, the waste water reduction strategy with the greatest positive environmental impact is source reduction, reducing the amount of water used in an industrial process and, therefore, the amount of water discharged as waste. The process basically involves identifying those processes for which water is absolutely necessary, such as cleaning, cooling or dissolving chemical compounds, and the minimum amount necessary to complete said processes. In the case of potentially hazardous liquid wastes like oily waste water that need special disposal or treatment, reducing the waste stream also reduces the disposal space or treatment energy needed to make the waste safe. Even in everyday processes like lubricating metal parts, cleaning the surfaces with dry rags reduces the amount of oily waste water created and extends the life of most oil-based lubricants.

Recycle and Reuse

• A second strategy for waste water reduction, recycling and reusing nonhazardous liquid waste, allows an industrial process to reduce the amount of clean water used and the amount of waste water generated. Water for cooling machine parts, for instance, does not have to be completely clean in order to be effective. Thus, using slightly contaminated water for different purposes reduces overall water use and waste production. Even in small-scale processes, keeping a bucket of water and using it to clean multiple surfaces rather than using running water dramatically reduces water use and the volume of oily waste water created.

Treatment

• End-of-pipe treatment is another important strategy in reducing industrial liquid wastes like oily water. Depending on the kind of oils dissolved in the water, a number of filtration and chemical processes can remove most or all of the oil suspended in the waste and create a stream of clean water that is less damaging to the environment and reusable for other processes. Even in household situations, simply running waste water through a sand filter -- even just a bucket of sand with some gravel and holes at the bottom -- can dramatically increase purity and turn waste water into a clean, usable resource.

Synergies and Priorities

• None of the above three treatments is exclusive. Combining all three approaches yields the most effective waste water reduction strategy. Limiting source use, determining exactly how much water is needed and identifying any wasteful process is the first step. Identifying the kind of water wastes being created and if any of them can be reused helps further reduce the amount of water waste. Finally, designing a treatment approach will minimize the environmental impact.