A phenomenon in which abnormal odors and taste (moldy odor, etc.) are detected in raw water, clean water, and distributed water due to the presence of microorganisms.This is a phenomenon whereby the coagulation, occulation, and sedimentation process is impeded by the presence of organisms, resulting in a large fraction of the suspended matter remaining in the water after the sedimentation process when normal amounts of coagulants are used.Attributable to organisms remaining and growing inside the ltration process, this phenomenon involves abnormal clogging of the lter layer, which reduces lter service life.This is a phenomenon whereby the turbidity of the ltered water increases due to the leakage of organisms from the ltration process.Countermeasure: Adding powdered activated carbon.Disadvantages: Increases operating costs, restricts/interrupts the water supply.Countermeasure: Increase the amount of coagulants used.Disadvantages: Increases operating costs.Countermeasure: Increase the frequency of ltration process cleaning.Disadvantages: Increases operating costs.Countermeasure: Increase the amount of chemicals added.Disadvantages: Increases operating costs, restricts/interrupts the water supply.❶O-avor❷Coagulation, occulation, and sedimentation inhibition❸Filtration blockage❹Filtration leakageIntake towerSettling processFlash mixing processFlocculationprocessSedimentationprocess・Sodium hypochlorite・ Sodium hypochlorite・Caustic soda・ Aluminum sulfate・Sodium hypochlorite・Caustic soda・Sodium hypochlorite・ Polyaluminum chlorideReception wellFiltrationprocessClean waterreservoirDistributionreservoirChemicals addedInux of phytoplanktonA phenomenon in which abnormal odors and taste (moldy odor, etc.) are detected in raw water, clean water, and distributed water due to the presence of microorganisms.This is a phenomenon whereby the coagulation, occulation, and sedimentation process is impeded by the presence of organisms, resulting in a large fraction of the suspended matter remaining in the water after the sedimentation process when normal amounts of coagulants are used.Attributable to organisms remaining and growing inside the ltration process, this phenomenon involves abnormal clogging of the lter layer, which reduces lter service life.This is a phenomenon whereby the turbidity of the ltered water increases due to the leakage of organisms from the ltration process.Countermeasure: Adding powdered activated carbon.Disadvantages: Increases operating costs, restricts/interrupts the water supply.Countermeasure: Increase the amount of coagulants used.Disadvantages: Increases operating costs.Countermeasure: Increase the frequency of ltration process cleaning.Disadvantages: Increases operating costs.Countermeasure: Increase the amount of chemicals added.Disadvantages: Increases operating costs, restricts/interrupts the water supply.❶O-avor❷Coagulation, occulation, and sedimentation inhibition❸Filtration blockage❹Filtration leakageIntake towerSettling processFlash mixing processFlocculationprocessSedimentationprocess・Sodium hypochlorite・ Sodium hypochlorite・Caustic soda・ Aluminum sulfate・Sodium hypochlorite・Caustic soda・Sodium hypochlorite・ Polyaluminum chlorideReception wellFiltrationprocessClean waterreservoirDistributionreservoirChemicals addedInux of phytoplanktonwater purication process. As the reve-nue from the water supply service con-tinues to fall and with labor shortages at purication plants, it’s becoming increasingly dicult to secure human resources with the skills needed to perform the bioanalysis necessary to manage the situation. ese issues helped dene the project trajectory.”What Rion already had were parti-cle counting technologies to monitor the counts and sizes of particles con-tained in a continuous ow of liquid. e development of a system for mea-suring water at water treatment plants began with the application of these technologies. Nearly one year had passed since the start of blindly search-ing for a new market.e water purication ow at puri-cation plants follows the processes as shown above. Phytoplankton blooms cause four major problems. Of these, Rion’s system appeared best-suited to managing the problem of ltration leakage ④.“With this problem, extremely small phytoplankton cells escape the ltration process and increase water turbidity. To solve this problem, it’s critically important to identify whether the suspended matter responsible is phytoplankton or some other particle. e type of chemical added to the water and the rate at which it needs to be added depends on the type of sus-pended matter causing the turbidity. Until then, no real-time monitoring system had been available. e person in charge of bioanalysis at the water treatment plant had to perform inspec-tions using microscopes and respond through trial-and-error based on expe-rience and instinct. is was an excru-ciatingly laborious task.”Sekimoto describes the technologi-cal aspects of this system as follows:“In the sensor unit, a purple laser beam is irradiated onto a quartz glass ow cell through which the sample water ows. As the laser beam passes through the ow cell, light is scattered by the particles (all particles including phytoplankton) in the sample water. e chlorophyll (chlorophyll α) within the phytoplankton cell induces red uorescence. e scattered light and the uorescence are detected separately. e detector unit for the scattered light provides information on the size and count of the particles, while the uores-cence detector unit provides infor-mation on the presence and intensity of the autouorescence from the particles. We can then use this information to distinguish phytoplankton from other particles. e results are output in real-time as the total count of particles passing through the laser beam, phyto-plankton count, the size of each parti-cle, and the intensity of autouorescence. is system is used as a powerful tool for identifying and managing the causes of these problems.”e Signicance of the Present Project for the FutureKatsuyoshi Tanaka has been involved with soware development at Rion ever since joining the company 35 years ago. He was in charge of manag-ing and modifying the soware for the XL-10A used at water treatment plants Flow of water at a water treatment plant (rapid ltration method) and biological fouling❹Kazuma SekimotoParticle Counter Sensor Development Section, Component Technology Develop-ment Department, Technical Develop-ment Center. A member of the project since working at the former R&D Center, he has been active on many fronts, such as market research for new business, planning, prototype production, valida-tion tests at water treatment plants, and business promotion.System Architecture DiagramMeasurements at water treat-ment plants are performed using a system architecture like the one shown to monitor the quality of clean water. The system is capable of performing real-time measurements of phytoplankton counts and particle counts of suspended matter. It helps us to improve efciency, reduce costs, and evaluate water purication.Flow of 10 ml/min generated by the dierence in water surface levels in the deforming tank and the water discharge outletFiltered water for dilution from lterINDeformingtankDeformingtankSample water (raw water, etc.) INSyringe pumpCleaning solution tankBackwashingdrainageControl unitWater discharged at 10 ml/minTap water for backwashingIN(100 kPa)FlowmeterPC for controlPhytoplanktoncounterCPU board for controlOVERFLOWOVERFLOWINLETOUTLET3
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