Vibratory finishing and associated industrial processes including ball burnishing and tumbling, produce fine particles. These particles are typically of the media used and of the materials being treated. The particles are often metal, but include other materials also. If the materials being treated are oil-coated, oil will also be present in the waste stream. The waste from these processes must be disposed of safely and according to environmental regulations. Typically the waste has low levels of solids, some oil, and a significant proportion of chemicals used in the process. The chemistry may be acid, caustic or neutral and serves one of several purposes in the finishing process.
Recovery of the chemical solution and concentration of the solids is a well established process using ultrafiltration. Dynatec has supplied many systems for this purpose. Ultrafiltration using tubular membrane modules allows for the chemical solution to pass through the membrane, while the remaining constituents of the waste stream including the fine solids and oils are retained and concentrated. In this way, recovery of the chemical solution is possible, while considerable reductions in waste disposal costs are also achieved. The ultrafiltration process consists of a feed or process tank into which the waste stream is fed. A circulation pump then passes the waste across the membrane surface at high velocity. The treated water and compound passes through the membrane and the remaining concentrated solids and oil are returned to the process tank. As treated water passes out of the system, more waste is added to the tank. Eventually, concentration of the waste is optimized and the process tank is emptied and the waste disposed of. The process is then repeated. High rates of recovery of the chemical solution is possible, often exceeding 99%. Periodically, a fouling layer may build up on the membrane surface. A cleaning compound is placed in the CIP (clean-in-place) tank that is part of the system. The circulation pump is used to circulate this fluid around the system, cleaning the membrane.
ULTRAFILTER MEMBRANE CLEANERS
Chemtrol membrane cleaning products effectively remove and control biofouling when used as part of the membrane cleaning procedure. By controlling organic and biofouling, operators achieve longer run times between chemical clean-in-place, and longer membrane life, saving time, money and increasing effective plant capacity.