Shower Water Filtration
October 25, 2001 ISSUE #122
Tests were recently conducted using a Vincent Fiber Filter on shower water at Atlantic Packaging in Scarboro, Ontario. The Fiber Filter was selected because of its small footprint and attractive capital cost compared to conventional filters.
This recycle paper mill has a combination OCC (Old Corrugated Container) and tissue operations. The most important use of shower water is on the felt of paper machines. Other applications are on trommel and rotary drum screens.
The primary source of shower water comes from disc strainers used at the end of the stock prep process. The disc strainers raise the paper pulp from 1.2% to 12% consistency. There are three effluents: cloudy, clear, and super clear. The cloudy effluent is pumped back to the start of the process at the hydrapulpers. The clear effluent is re-used half way back in the stock prep process, with the excess going to sewer.
The disc filter itself uses some of the super clear; the rest is filtered prior to use as shower water. The existing super clear water filters are Sweco machines that feature a vertical axis with a spinning drum screen. The drums have fabric panels backed up with coarse mesh steel screen. The drums are about 4' in diameter.
These Sweco's are very old and have served their purpose; maintenance expense has become excessive. Thus our Fiber Filter is being evaluated as a potential replacement.
The very low solids consistency of the super clear water resulted in high capacity in the Fiber Filter even with very fine fabric sleeves. With a feed consistency of 70 ppm, using a 31 micron sleeve, we were able to produce filtrate with 20 to 25 ppm. This was done with the Model FF-12 being fed about 200 gpm and producing about 1 gpm of fiber-sludge discharge.
A goal of the project is to eliminate the need for addition of city water make-up to the shower water tank.
There is a rule-of-thumb used in selecting filters used on flows ahead of spray nozzles: The filter basket should have openings one tenth the size of the openings of the shower nozzles. This is achieved with the 20 and 31 microns sleeves available for use with the Fiber Filter machines.