Efficient Plant April 2020 - 16

feature | environmental strategies
mix of operations at a processing site. The
treat large wastewater flow rates.
advanced membrane technology used
Paper-bed filters: These types of filters
in UF provides a simplified, effective,
work by gravity and use disposable paper
and superior solution for removing
media or permanent filter media.
soluble heavy metals. UF systems
This produces a positive barrier that
allow finishing operations to
removes solids from all free-flowing
reuse as much as 98% of their
industrial process liquids. Paper-bed
surface-finishing wastewater
filters are suitable for applications
without the use of chemical
involving low- to medium-stock
additives.
removal of ferrous and nonMembrane technology proferrous metals, as well as organic
vides numerous advantages to the
and inorganic contaminants such as
process of surface-finishing wasteglass, rubber and plastic. Paper-bed
Selecting the proper system for
treating wastewater can result in
water treatment, including:
filters can extend coolant and tool life by
significant savings and greatly reduce
 eliminating the need for clarifiers or
an average of 27%, in addition to increasing
environmental impact.
lamella separators
surface-finish quality.
 not requiring coagulants for processing
Solid-bowl centrifuges: These units optimize
 reducing the volume of sludge generated
centrifugal force (instead of consumable media) to separate
 lowering labor costs
solids from liquids in metal-processing applications where removal
 reducing chemical costs
of fines is important for recycle and reuse goals. Process liquid is
 producing a more consistent effluent.
either pumped or gravity-fed to the centrifuge inlet. Process solids
Reverse-osmosis systems: RO technology removes dissolved solare then centrifugally separated from the liquid phase and collected
ids and impurities by using a semi-permeable membrane that allows
in an easily removable rotor. Clarified liquid overflows the rotor into
the passage of water but leaves the majority of dissolved solids/salts
the outer case and is returned by gravity to the process. Solid-bowl
and other contaminants behind. A properly designed and operated
centrifuges provide high-performance liquid/solid separation for all
RO system can remove as much as 99.5% of incoming dissolved
types of particles.
salts and impurities, as well as virtually all colloidal and suspended
Tramp-oil separators: In this wastewater treatment solution, conmatter from the most challenging waste and feed-water applications.
taminated fluid flows through a series of baffles and a porous media
Typically used in industrial, metalworking, and surface-treatment
bed, where free and mechanically dispersed oils are separated from
operations, RO technology is the final process after ultrafiltration or
the fluid. The clarified fluid then flows over an effluent discharge
the chemical treatment of waste and feed water.
wier back to the reservoir for reuse. The oils, inverted emulsions,
Vacuum evaporation and distillation: Evaporation is a natural
and other waste materials are collected at the top of the separator
phenomenon and a clean separation technology recognized as a
and automatically discharged into a suitable receptacle. Using gravbest-available technique (BAT) in several wastewater-treatment
ity flow and coalescence, these separators can reduce tramp oils to
processes. Because it removes the water from the contaminants,
less than 1% in a single pass while using no consumable products.
rather than filtering the contaminants from the water, it is distinct
Vacuum filters: Capable of continuous operation, vacuum filtrafrom other separation processes. Vacuum evaporators treat and
tion systems can eliminate downtime. Virtually maintenance-free
distill industrial wastewater amounts from 1 to 120 tons per day.
and delivering high-sludge-volume elimination, the systems will also
They are capable of achieving residual total solids concentrations of
deliver lower production costs. Disposable-media vacuum filters use
more than 85%.
a vacuum chamber to draw contaminated coolant through the disThe three primary vacuum evaporators are:
posable filter media. By applying the principle of optimal filtration
 heat pumps, which are flexible and versatile with low electricalthrough contaminant or sludge build-up, a filter cake forms on the
energy consumption
media. These units are capable of flow rates as high as 2,000 gpm. EP
 hot water/cold water, which reduces operating costs by using existing excess hot water/steam and cooling water
Tim Hanna is Vice President of Business Development for PRAB,
 mechanical vapor recompression (MVR), which is engineered to
Kalamazoo, MI (prab.com).

EP2004fprab.indd 16

| EFFICIENTPLANTMAG.COM

APRIL 2020

3/27/20 12:25 PM

http://www.prab.com http://www.EFFICIENTPLANTMAG.COM

Efficient Plant April 2020

Table of Contents for the Digital Edition of Efficient Plant April 2020