Industrial Wastewater treatment equipment has become an increasingly critical part of plant operations over the past decade, and manufacturing companies in all industrial sectors are prioritizing water consumption reduction. Compliance with ever-tightening federal wastewater treatment, handling, and disposal regulations requires finishing industry executives to focus on the issue. Additional motivating factors for recycling industrial wastewater include strengthening a company’s public image, improving the overall work environment, boosting employee morale, and adhering to ISO 14001 initiatives.
The ultimate motivator is almost always related to cost. From a strictly monetary standpoint, it makes sense for finishing shops to adopt a formal wastewater treatment and reuse policy, as it allows them to cut rising operational costs while dramatically increasing profitability. Most of the hazardous waste in surface finishing comes from wastewater generated by rinse water.
The apparent goal should always be to prioritize water use reduction and recycle wastewater internally. This will increase equipment life, improve product quality, reduce maintenance costs, and extend the lifespan of working fluids. Implementing an industrial wastewater treatment system means that when the time comes to dispose of wastewater, finishing shops can virtually eliminate the volume that needs to be disposed of or hauled away.
The heart of any system is the equipment. Several options are available, each designed to perform specific types of treatment and deliver a quick return on investment (ROI).
The concentration and chemical form of the soluble heavy metals in a wastewater stream varies, depending on the industry and the mix of operations at a processing site. The advanced membrane technology used in UF provides a simplified, effective, and superior solution for removing soluble heavy metals. UF systems enable finishing operations to reuse as much as 98% of their surface-finishing wastewater without the need for chemical additives.
Membrane technology provides numerous advantages to the process of surface-finishing wastewater treatment, including:
RO technology removes dissolved solids and impurities by using a semi-permeable membrane that allows water to pass through while retaining most dissolved solids, salts, and other contaminants. A properly designed and operated RO system can remove as much as 99.5% of incoming dissolved salts and impurities, as well as virtually all colloidal and suspended matter from the most challenging waste and feed-water applications. Typically used in industrial, metalworking, and surface treatment operations, RO technology is the final process after ultrafiltration or chemical treatment of waste and feed water.
Evaporation is a natural phenomenon and a clean separation technology recognized as a Best Available Technique (BAT) in several industrial wastewater treatment processes. Because it removes water from the contaminants rather than filtering the contaminants out of the water, it is distinct from other separation processes. Vacuum evaporators treat and distill industrial wastewater at rates of 1 to 120 tons per day. They can achieve residual total solids concentrations of more than 85%.
The three primary vacuum evaporators are:
These types of filters work by gravity and use disposable paper media or permanent filter media. This produces a positive barrier that removes solids from all free-flowing industrial process liquids. Paper-bed filters are suitable for applications involving the removal of low- to medium-stock ferrous and non-ferrous metals, as well as organic and inorganic contaminants such as glass, rubber, and plastic. Paper-bed filters can extend coolant and tool life by an average of 27%, while also improving surface finish quality.
These units optimize centrifugal force (instead of consumable media) to separate solids from liquids in metal-processing applications where the removal of fines is essential for recycling and reuse goals. Process liquid is either pumped or gravity-fed to the centrifuge inlet. Process solids are then centrifugally separated from the liquid phase and collected in an easily removable rotor. Clarified liquid overflows the rotor into the outer case and is returned to the process by gravity. Solid-bowl centrifuges provide high-performance liquid/solid separation for all types of particles.
In this wastewater treatment solution, contaminated fluid flows through a series of baffles and a porous media bed, where free and mechanically dispersed oils are separated from the fluid. The clarified fluid then flows over an effluent discharge wier back to the reservoir for reuse. The oils, inverted emulsions, and other waste materials are collected at the top of the separator and automatically discharged into a suitable receptacle. Using gravity flow and coalescence, these separators can reduce tramp oil to less than 1% in a single pass, utilizing no consumable products.
Capable of continuous operation, vacuum filtration systems can eliminate downtime. The systems will be maintain-free and deliver high-sludge-volume elimination and lower production costs. Disposable-media vacuum filters use a vacuum chamber to draw contaminated coolant through the disposable filter media. By applying the principle of optimal filtration through contaminant or sludge build-up, a filter cake forms on the media. These units are capable of flow rates as high as 2,000 gallons per minute (gpm). EP
Tim Hanna is Vice President of Business Development for PRAB, Kalamazoo, MI.
A version of this editorial was published on efficientplantmag.com.
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