ブックタイトルMGH移動脱水車カタログ（英語版）

概要

MGH移動脱水車カタログ（英語版）

e flow of sewage treatment ( in japan )①Settling basin③Biological　reaction tank④Final　sedimentation　tank⑤Disinfection　equipment⑥Sludge　thickener⑧Dehydrator⑨Incinerator⑩Iincinerated ash⑪Advanced　treatment　equipment⑦Sludge　storage tank②Primary　sedimentation　tankRemove the sand easy to settle and solid waste of large size by screens.Wash the sand which has settled at the bottom of the tank and fill up on the landfill disposal site.Incinerate most of the waste such as sanitary paper and vegetable scraps gathered by screens andfill up the other trash.Add carrier sludge into the tank, and activates the microorganisms by blowing air. Highconcentrated microorganisms adsorb and take in organic matter, and nitrification anddegradation of organic matter proceed.It is said that there are about 5000-20000 protozoa and small metazoan in all in a 1ml liquid whichsewage and activated sludge are mixed in the reaction tank.Precipitate the activated sludge slowly (mass of microorganisms) . Activated sludge whichhas precipitated is returned to the biological reaction tank and becomes active again.Microorganisms are always in the waterside such as rivers and ponds, and flows into the waterreclamation center along with the sewage gradually. They become the activated sludge incresinglarge quantities in the reaction tank which are rich in air and nutrition. As the "seed sludge", sendback a part of activated sludge which has sunk to the bottom in the final sedimentation tank, to thereaction tank.Disinfect by injecting chemicals.Bacteria that are in treated sewage is usually harmless to the human body. Disinfect in order toenhance the safety of the final effluent. In disinfection, Chlorination using the bactericidal actionof chlorine is often used. In the other methods, the bromine, the ozone, and the ultravioletdisinfection are used.Reduce the volume of the sludge in the same tank as the sedimentation tank.Just only 0.5～1 percent of precipitated sludge in the sewage treatment facility is mud (sollidmaterials), that contains a lot of water, so it is necessary to reduce water. Its way is as follows:Gravity thickening, which using the fact that sludge is a little heavier than water. Centrifugalthickening, which using the centrifugal force such a as spin dryer. Flotational thickening, whichcombine air and bubbles and sluge with chemicals to make sludge float up.Reduce moisture further using chemicals.A certain amount of sludge is accumulated in the sludge accumlation tank. Add a flocculantwhich promotes to separate water and sludge.Incinerated ash is reused and recycled. The rest is landfilled.While make efforts to decrease the quantity of sludge generated everyday, use the sludge as aresource.Mix flocculants and reduce water further squeezed by machines.Belt press dedehydrators and centrifugal dehydrators are often used. First one, which putsludge between two sheets of cloth, and squeeze out water by applying pressure from bothsides. Second one, in the same principle as the spindrier of the laundry, put sludge into the tankand collect water on the outside by the rotation.Reduce the volume by incineration at high temperatures. Organic matter is burned andstabilize.You can also perform the area-wide air conditioning business using the waste heat of sludgeincinerators. In addition, the temperature of sewage is lower than the air in summer, and higherthan the air in winter. By making use of that characteristics, some areas do business of thecooling-and-heating.It is the equipment to clean further treated water.Clean more sewage, with the advanced treatments that submerge the organic matter such asprotein, fat, and carbohydrates, or eat in microorganisms, or stimulate microorganisms foractivitiers. In order to promote the improvement of the waterfront environment, the advancedtreatment with microorganisms remove even the nitrogen and phosphorus, that is causativematerials of red tide.Make a gentle flow of sewage, then precipitate small insoluble dirt slowly. Precipitated slugeis sent to the sluge thickener, and supernatant is sent to the biologocal treatment tank.In sewage treatment facilities, unpleasant smells may drift from various places. In places wherethe odor is easy to get, equipments are required to seal or to remove the odor (deodorizationsystem). There are the following deodorization methods; the activated carbon deodorization, inwhich activated charcoal adsorbs odors; the biological deodorization, in which microorganismseat the smell; the incineration deodrization, in which gather and burn smelly air in the sludge tank.