City of Santa Rosa Utilities Department
March 21, 2001
Subject: Schaner's Polygone Suppress
The City of Santa Rosa's Laguna Wastewater Treatment Plant employs four Ashbrook
Winklepresses for dewatering anaerobically digested biosolids, which are a mixture
of primary and secondary sludges. The formation of struvite on the presses has
been a major contributor to maintenance problems since startup and the driving
factor in our press rebuilding program. In the past we have found it necessary
to rebuild our presses at four year intervals. This was primarily due to damage
caused by struvite deposits on wear surfaces and the plugging of drainage passages.
Both mechanical removal of struvite and chemical removal treatments have been
used in the past. Both methods are labor intensive and cause considerable equipment
downtime, and neither method could get all the struvite in hard to reach places.
In late 2000, Schaner's fitted one of our presses with application and metering
equipment. All visible struvite was removed from the press within three weeks.
We since have had the equipment installed on the remaining three presses and
are achieving the dame results. Though it is too soon to quantify, we anticipate
being able to stretch our major service interval considerably through the use
of Polygone Suppress, and also anticipate increased belt life as there is virtually
no struvite being deposited on the rollers so the belts can run straight and
true, as they were designed to do. In addition to our success with the product,
we have been thoroughly pleased with the way Schaner's does business. All schedules
were met, downtime was minimized, and installation was performed with no disruption
of production, we have found customer service to be excellent in all respects.
The use of Schaner's Polygone has been the single most effective measure we
discovered to ease the maintenance load in our belt press facility. Please feel
free to call me at 707-543-3374 if you have any question regarding our experience