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From Water and Wastewater.com Wastewater
Installed last November, the Monster Separation System™, which integrates a Bandscreen Monster™ with a Screenings Washer Monster® provides for an initial screening of solids, plus processing of remaining solids (screenings) by grinding, washing, dewatering, and compacting.. The unit was designed and manufactured by JWC Environmental in Costa Mesa, CA. “The membranes in the new MBR plant are really expensive, and we wanted to be sure to have the best screening ahead of them so we don’t get grit or other material that could damage them,” explained Hank Day, maintenance and operations foreman for Star Sewer and Water District. “We also wanted to filter out as much total solids as we could, to keep the new MBR plant running at optimum capacity. This combination solids processing system allowed us to meet both objectives from the outset of the new plant operation. Anytime you’re dealing with wastewater, it’s a lot easier and cheaper to do it right the first time than to come back and add stuff later.” “Meanwhile, we’ve already gotten a big benefit with the aerators in our lagoons not plugging up anymore. We had been pulling all nine of them for a day, ten times a year, for cleaning. We haven’t had to do that at all since we installed the MSS.” The WWTP now serves about 2,000 residential customers and another 25 or so commercial operations. The new Kubota® MBR plant, featuring state-of-the-art technology, opened last January as the means for handling a dramatic continuing increase in the customer base. Their lagoons were already filled to capacity. At the WWTP’s headworks, a manual bar screen removes rags and other large matter. The flow then moves through a grit remover, which deposits to a 3-yd dumpster. The remaining wastewater stream then enters the Monster Separation System (MSS), which consists of a 2 mm Bandscreen for removal of solids such as trash and plastics, integrated with a Screenings Washer Monster (SWM), which grinds, washes, dewaters, and compacts the solids and discharges them into the grit dumpster. The discharge from the MSS proceeds through a flow meter to a splitter box, which sends 20% of the stream to the three 1600 equivalent dwelling unit (edu) lagoons, and 80% into the new MBR plant. In the new plant, another splitter box sets up two separate treatment chains, where anoxic and anaerobic cells see mixtures of raw activated sludge (RAS), raw influent, and mixed liquor from membranes, and provide biomass “bugs” for the MBR’s. The membrane portion currently consists of 200 flat plate membranes per cassette, and twelve cassettes for each train. Flow in both the east and west trains is now about 0.3 mgd. Allowance has been made for future expansion of capacity of the MBR via more membranes in each train, as well as additional trains. The MBR discharges to a chlorine contact basin, for final disinfection before the effluent is discharged. Overall, the 1.2 mgd peak flow WWTP is presently operating at about 0.8 mgd. “They’re building 20 new subdivisions in our area as we speak,” continued Day. “To upgrade, we did everything at the very best we could afford and still be easy to operate. The Idaho Dept. of Environmental Quality lent us money to build it, and they like what they’ve seen so far.” “The 3 yd. dumpster, which took about a month to fill up with ground material, now gets emptied every two weeks, only because we also fill it with trash. The cleanliness of the discharged solids (from the SWM) allow for hauling to a sanitary landfill, which was a compliance criterion that was assured by our engineers, Keller Associates of Meridian, ID.” “The JWC unit has been working fine. We check it daily, along with the rest of the plant, for cleanliness and neatness, and that’s all we’ve had to do. ” Day adds, “In considering alternatives, we had originally settled on a Bandscreen versus a step screen because it would let in less solids, and then specified a 2 mm size to meet the MBR plant manufacturer’s warranty. We then selected the JWC Monster Separation System as it is easiest to operate and maintain. For example, it didn’t have any bearings down in the waterway, and you could take out sections of the belt (Bandscreen) without taking out all of it, which would require disassembling the whole unit.” JWC‘s Monster Separation System offers exceptionally high capture rates, and the ability to remove a wider variety of solids, particularly small solids and trash, than traditional screens. After conditioning inside the SWM the removed solids are up to 50% dry and 80% compacted; moreover, they are significantly lighter and cleaner than typical screened solids. The Bandscreen’s rotating panels are positioned parallel to the incoming flow. As wastewater enters the screen, it flows left or right through the perforated screening panels, which are available in 2, 3 or 6mm openings. Its special design eliminates any need for sprockets or bearings in the flow (waterway). Unwanted solids are captured and lifted to the discharge level, where a spray system washes solids into a trough which flows into the self-contained, hopper-fed Screenings Washer Monster for grinding, washing, dewatering and compacting. Its unique process of grinding prior to solids separation removes virtually all the soft organics (fecal) from the discharged product, which reduces odors and landfill costs. For further information, contact: JWC Environmental 290 Paularino Ave. Costa Mesa, CA 92626 Telephone: 800/331-2277 Fax: 949/833-8858 Email: jwce@jwce.com Web: http://www.jwce.com/ © Copyright 1998 - 2008 Water and Wastewater.com |
