In wastewater treatment, Fine Screening is using screens with openings less than 6mm (1/4”), such as 1mm, 2mm, 3mm and 5mm. The main purpose of wastewater screening is to remove solid materials that cause a variety of problems in treatment plants. However, conventional coarse screens 6mm or wider can only prevent damage to downstream equipment and do not address various other problems. For this reason, governments are revising guidelines to implement screens with 2mm to 5mm openings at the headworks of sewage treatment facilities.
Fine screens with 2mm or 3mm openings placed at the beginning of the treatment process remove scum and stringy materials which are able to pass through coarse screens. This eliminates almost all unwanted material, solving many chronic problems found in wastewater treatment plants. Our Micro Bar Screen is the only reliable fine screen that can effectively screen at 1mm, 2mm and 3mm without clogging.
Generally, there are two ways screen openings become blinded. The first is by immediate clogging of openings with near-size particles (particles that are almost the same width as the openings). The second is by gradual blinding of the openings by accumulation of contaminant on the screen media face with greasy or sticky material. The latter makes the openings gradually smaller, and within several months the screen becomes totally blinded, even if cleaning showers or brushes are used. By that point, even a manual cleaning by the operator will not completely remove all the contaminants, because a layer of bacterial plaque as hard as stone will have already formed.
Fine screens made with wire mesh or perforated plates easily become blinded as the cleaning showers and brushes cannot dig material out of every hole. The same issue occurs with drum screens made of wedge wire. Although a high-pressure cleaning shower is used, the nozzles spread the stream to an area 100 times wider than the actual nozzle hole, and the water does not impact with enough force to completely clean deep into the openings. However, Micro Bar Screen’s rake teeth thoroughly and consistently slit the openings as narrow as 1mm while discharging the captured screenings.
Micro Bar Screen is the only fine screen that never blinds and never requires any manual cleaning! For this reason, many plants are replacing their fine screens with Micro Bar Screens.
Seven patented technologies (including patents in USA, Korea, and China) ensure that each Micro Bar Screen operates safely and flexibly for over 10 years. The Retroflexing Rake enables instantaneous and repeatable protection of the screen without jamming or requiring any manual reset. This prevents operation shutdown and overflow.
Micro Bar Screen completely eliminates the need for large amounts of cleaning water and pumping energy. There is also no need for a rotating brush that requires frequent maintenance to remove tangled hairs and materials stuck between the bristles.
"The Korean government amended the Guidelines for National Sewage Treatment Facilities in 1998 to install fine screens with 2mm to 5mm openings, in order to reduce scum at the primary settling basin or aerating basin, and to prevent incoming contamination loads from exceeding the design factor of the primary settling basin."