Grit and Oil Removal Systems Brochure

ECOMACCHINE S.p.A.Via Vandalino 610095 Grugliasco (TO)Tel.: +39.0114028611Fax: +39.0114028627Email: ecomacchine@ecomacchine.itWeb: www.ecomacchine.itGRIT AND OIL REMOVAL SYSTEMSThe second mechanical treatment of the waste water is the grit and sand removal; sometimes thegrit removal tank contains also the oil removal system. The grit removal process consists inremoving the substances which have a specific weight and hydrodynamic characteristics similar totrue sands, such as glass and metal pieces, egg-shells, seeds, fruits-stones, coffee–beans, ashes, clay,mould, etc... Many of these substances are abrasive and may cause damages to the equipments.There are a few types of Grit Removal Systems:• channel type, normally aerated and with a lateral oil removal zone;• “vortex” type, in a circular tank;• detritor type, in a square tankThe size of the solids separated by the Grit Removal System is larger than 200 microns. These solidscontain some water. The solids can be separated from water through a sand filter, drying bed type,or by means of solid/water separators. Our range of production includes the following types of Grit RemovalSystems:Grit and oil removal scraper bridge for rectangular tank, aerated type - mod. EM54 Grit and oil removal scraper bridge for rectangular tank, suction type - mod. EM55 Grit and oil removal system for rectangular tank, suitable for covered tanks - mod. EM52A “VORTEX” type grit removal system mod. EM40A “VORTEX” type grit and oil removal system mod. EM40B Grit removal system, detritor type, with scraper - mod. EM42Accessories:Grit separators: Screw type grit separator mod. EM39 Reciprocating grit separator with scrapers mod. EM41 Air-lift mod. EM77OUTLINES OF THE GRIT REMOVAL PROCESSThe waste water often contains a large quantity of inert materials, mainly inorganic, which aregenerally defined as grit, even if actually the quantity of sand/grit is only a part of this type ofmaterials. In fact, in the waste water treatment field, the words “grit” or “sand” do not refer only tothe siliceous sands, of various sizes, but they are more commonly intended as the group of heavyinert materials which can be found in the waste water. The greatest quantity of grit reaches thewaste water treatment plant during rainy periods, also because the cities sewer systems usually havea slight slope, and then a slow speed, and the sediments are dragged when the flow rate is rising.A good grit removal system should sediment all and only the grits, of any size. The sedimentation ofthe organic materials should be avoided because the presence of putriscible materials in the removedgrit would make them unusable or would not allow a direct elimination because it should bethouroughly washed. Anyway in the grit removal systems, even if well sized and designed, there is always a small quantityof organic material. To achieve a good grit separation there must be some specific physical conditions which allow toexploit the phenomenon of the difference of sedimentation speed between the particles of inertmaterial, which sediment more quickly, and the particles of organic material. There are a few types of Grit Removal Systems: gravity grit removal systemswhere the grit separation is achieved only by gravity (channel type systems)mechanized grit removal systemswhere the grit separation is helped by the rotation of a turbine (VORTEX type systems)aerated grit removal systemswhere the grit separation is helped by the air blown from the bottomIn the aerated grit removal systems the turbulence due to the air helps the grit separation and thesuspension of the organic material. The addition of a vertical baffle in the aerated grit removal systems makes the oils separation easier.They are collected in a calm zone, after the baffle. The following table shows the percentage of the grit separation, depending on the granules size andthe time of permanence in the tank. GRIT AND OIL REMOVAL SCRAPER BRIDGE, AERATED TYPEMOD EM54Application Grit and oil removal from municipal and industrial waste water.CharacteristicsLongitudinal flow channel, with tapered section (downwards). The channel is divided into two zones: the grit removal zone (normallyaerated) the oil removal zone. The two zones are separated by alongitudinal baffle.OperationThe waste water goes through the grit removal system longitudinally;the grit which sediments on the bottom is scraped and conveyed intoa hopper and then lifted by air-lifts or submersible pumps.The floating substances in the oil removal zone are conveyed to thehopper by a surface scraper.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete channel.Separation Grit particles larger than 200 microns.OptionalSeparation between grit removal-oil removal zones. Power supply by cable winding reel. Air blowing system.Operation descriptionThe water speed in the grit removal channel is lower than 0.3 m/sec., therefore the grit having alarger size than 200 microns settles on the bottom. The air distributed by the diffusers fluidifies thegrit before it sediments and removes the organic substances which deposit on it. These organicsubstances and the other substances in the water, thanks to the air effect, float and flow together tothe oil removal zone which is on the channel side and is not aerated, then they are taken away by asurface scraper. The grit settled on the bottom is conveyed to the hopper by the bottom scraper. The recommended air delivery is of 10-15 Nm3/h per metre of length of the grit removal channel.Mechanical solutions for the scraper bridges:scraper bridge with concrete runways, equipped with tyred wheels and contrast wheelsscraper bridge with railsTechnical data1.1 Max. flow rate in the channel :m³/h (*)1.2 Width of the grit removal zone :mm. (*)1.3 Width of the oil removal zone :mm. (*)1.4 Channel length :mm. (*)1.5 Aeration zone air flow rate :m³/h(*) To be advised when asking for a quotationGRIT AND OIL REMOVAL SCRAPER BRIDGE, SUCTION TYPEEMOD EM55Application Grit and oil removal from municipal and industrial waste water.CharacteristicsLongitudinal flow channel, with tapered section (downwards). Thechannel is divided into two zones: the grit removal zone (normallyaerated) the oil removal zone. The two zones are separated by alongitudinal baffle.OperationThe waste water goes through the grit removal system longitudinally;the grit which sediments on the bottom is lifted and conveyed to alateral channel by air-lifts or submersible pumps. The floatingsubstances in the oil removal zone are conveyed to the hopper by asurface scraper.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete channel.Separation Grit particles larger than 200 microns.Grit liftingsystemsAir-liftSubmersible pumpVertical pumpOptionalSeparation between grit removal-oil removal zones.Power supply by cable winding reel.Air blowing system.Operation descriptionThe water speed in the grit removal channel is lower than 0.3 m/sec., therefore the grit having alarger size than 200 microns settles on the bottom. The air distributed by the diffusers fluidifies thegrit before it sediments and removes the organic substances which deposit on it. These organicsubstances and the other substances in the water, thanks to the air effect, float and flow together tothe oil removal zone which is on the channel side and is not aerated, then they are taken away by asurface scraper.The grit settled on the bottom is lifted by a submersible pump or air-lift and conveyed to the lateralchannel.The recommended air delivery is of 10-15 Nm3/h per metre of length of the grit removal channel.Mechanical solutions for the scraper bridges:scraper bridge with concrete runways, equipped with tyred wheels and contrast wheelsscraper bridge with railsTechnical data1.1 Max. flow rate in the channel :m³/h (*)1.2 Width of the grit removal zone :mm. (*)1.3 Width of the oil removal zone :mm. (*)1.4 Channel length :mm. (*)1.5 Aeration zone air flow rate :m³/h(*) to be advised when asking for a quotationGRIT AND OIL REMOVAL SUBMERSIBLE SYSTEMMOD EM4953Application Grit and oil removal from municipal and industrial waste water.CharacteristicsThe machine is equipped with a bottom screw to collect and conveythe grit and with oil removal blades in the upper part.OperationThe grit settled on the bottom is removed in continuous and taken tothe drain trap. The floating substances are conveyed in continuous bythe surface blades.MaterialsEquipment with standard components of easy installation, normally instainless steelInstallation In a concrete channel, even covered.Separation Grit particles larger than 200 microns.AdvantagesThe tank can be covered, the continuous operation of the bottomscrew and surface blades allow to treat successfully waste waters withhigh loads of solids and oily substances.OptionalSeparation between grit removal-oil removal zones.Air blowing system.Operation descriptionThe water speed in the grit removal channel is lower than 0.3 m/sec., therefore the grit having alarger size than 200 microns settles on the bottom. The air distributed by the diffusers fluidifies thegrit before it sediments and removes the organic substances which deposit on it. These organicsubstances and the other substances in the water, thanks to the air effect, float and flow together tothe oil removal zone which is on the channel side and is not aerated, then they are taken away bysurface blades.The grit settled is removed by a bottom screw.The recommended air delivery is of 10-15 Nm3/h per metre of length of the grit removal channel.Technical data1.1 Max. flow rate in the channel :m³/h (*)1.2 Width of the grit removal zone :mm. (*)1.3 Width of the oil removal zone :mm. (*)1.4 Channel length :mm. (*)1.5 Aeration zone air flow rate :m³/h1.6 Electric motor for hydraulic unit :Kw.(*) to be advised when asking for a quotationVORTEX TYPE GRIT REMOVAL SYSTEM MOD EM40AApplication Grit and oil removal from municipal and industrial waste water.Characteristics The system is made up of a turbine and an air-lift.OperationThe water to be treated goes through the grit removal system with atangential flow; the grit which sediments on the bottom is lifted by anair-lift.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete channel.Tank diameter From 1000 to 5000 mm.Separation Grit particles larger than 200 microns.AdvantagesThe grit moved by the turbine is partially separated from the organicsubstances.DisadvantagesLimited capacity of treatment.It does not include any oil removal system.Optional BlowerOperation descriptionThe water flows into the grit removal tank in a tangential way and the blades keep the liquid inmotion at any level of flow rate. The tangential flow and the blades rotation make the grit particlessediment on the bottom. The grit is lifted by an air-lift and is conveyed to a mechanical separator or to a simple draining andfiltering bed.The grit removed is clean enough thanks to the separation of the organic substances due to theeffect of the rotary blades.Sometimes, to avoid the arising of decomposition phenomena due to the inevitable presence oforganic material, a certain number of washings by water or air are necessary before extracting thegrit.This type of grit removal system does not separate any oily substances.Technical data1.1 Waste water delivery to the grit removal system :m³/h (*)1.2 Useful diameter :mm.1.3 Water and sand flow rate in the air-lift :m³/h (*)1.4 Air-lift size :DN.1.5 Rotation speed :rpm 30(*) to be advised when asking for a quotationVORTEX TYPE GRIT AND OIL REMOVAL SYSTEMMOD EM40BApplication Grit and oil removal from municipal and industrial waste water.CharacteristicsThe system is made up of a separation cylinder, air diffusers and anair-lift.OperationThe water to be treated goes through the grit removal system with atangential flow; the grit which sediments on the bottom is lifted by anair-lift. The oily substances which float due to the effect of the airblowing are evacuated by means of a valve, normally with a manualcontrol.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete tank.Tank diameter From 1000 to 5000 mm.Separation Grit particles larger than 200 microns.Advantages It is equipped with oil removal system.Disadvantages Limited capacity of treatmentOperation descriptionThe water flows into the grit removal tank in a tangential way. The tangential flow helps the gritparticles sedimentation on the tank bottom.Normally the suspension remains in the tank more than 30 seconds.The flotation of the organic substances is due to the air blowing.The grit is lifted by an air-lift and is conveyed to a mechanical separator or to a simple draining andfiltering bed.The oils flow together outside the separation ring and are regularly removed by means of a manualblade or gate valve.The grit removed is clean enough thanks to the separation of the organic substances due to theeffect of the air blowing.To avoid the arising of decomposition phenomena due to the inevitable presence of organic material,a certain number of washings by water are necessary before extracting the grit.Technical data1.1 Waste water delivery to the grit removal system :m³/h (*)1.2 Useful diameter :mm.1.3 Water and sand flow rate in the air-lift :m³/h (*)1.4 Air-lift size :DN.1.5 Air flow rate :Nm³/h(*) to be advised when asking for a quotationDETRITOR TYPE GRIT REMOVAL SYSTEMMOD EM42Application Grit removal from municipal and industrial waste water.Characteristics The system is equipped with baffles and grit scrapers.OperationThe water to be treated goes through the grit removal system with alaminar flow; the grit which sediments on the bottom is conveyed tothe sides and evacuated by an air-lift.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete tank.Tank diameter From 2000 to 16000 mm.Separation Grit particles larger than 200 microns.Optional Air-lift for grit evacuationOperation descriptionThe water flows into the grit removal tank from the side. The water flow must have a laminarmotion.The baffles placed at the entry are installed in such a way to distribute the water homogeneously, allover the tank width.The grit which sediments on the bottom is scraped and conveyed to the periphery of the tank whereit is lifted and evacuated by an air-lift.The average water level in the tank is 700-1000 mm.Technical data1.1 Waste water delivery to the grit removal system :m³/h (*)1.2 Width x length :mm.1.3 Water and sand flow rate in the air-lift :m³/h (*)1.4 Air-lift size :DN.1.5 Rotation speed of the scrapers :rpm(*) to be advised when asking for a quotationGRIT SEPARATOR AND WASHERMOD EM39Application Separation of sand and other solids from waste waterCharacteristicsThe machine is equipped with a screw which carries the solid materialsfrom the channel bottom to the top.Operation ContinuousMaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation Free standingSeparation Starting from 200 micronOptional Air separator for sand coming from air-lift.Operation descriptionThe water to be treated is conveyed into the feed hopper where the sand and any other solidparticles decantation process takes place.The screw lifts the solid materials from the hopper to the discharge outlet.After having been separated from water, the sand is washed with clean water by a spraying nozzle;the dirty water returns to the tank and the washed sand is lifted by the screw.At the first starting, before the grit is lifted and evacuated outside the machine, the solid materialsmust begin settling down to form a bed of grit.When a sufficiently thick bed of grit is formed, the equipment begins evacuating the solid material(grit).Technical data1.1 Waste water delivery to the sand classifier :m³/h 35 50 801.2 Volume of the hopper mm. 800 1400 20001.3 Sand flow rate that can be lifted :m³/h 1 2 21.4 Spiral diameter :mm. 200 280 2801.5 Screw rotation speed :rpm. 5 5 51.6 Electric motor :kw 0,25 0,55 0,751.7 Power supply V-f-Hz 380-3-50 380-3-50 380-3-501.8 Electric motor poles :n° 4 4 41.9 Electric motor protection :ip 55 55 551.10 Insulation class F F F1.11 Machine total weight :kg 1250 1450 1950RECIPROCATING GRIT SEPARATOR AND WASHERMOD EM41Application Separation of sand and other solids from waste waterCharacteristicsThe machine is equipped with a series of parallel plates which lift thesolid materials from the channel bottom to the top.OperationThe grit settled on the bottom is dragged by the scrapers which havea reciprocating motion out of the water. Before being discharged, thegrit is washed with water.MaterialsCompact equipment in hot dip galvanized carbon steel or stainlesssteel.Installation In a concrete channel.Channel width From 300 to 1500 mm.Separation Starting from 200 micronsAdvantagesThe grit scrapers do not lay on the bottom, therefore they are notsubject to wear.Operation descriptionThe water to be treated is conveyed into the feed hopper where the sand and any other solidparticles decantation process takes place.The grit scrapers, thanks to their reciprocating motion, lifts the solid materials from the hopper tothe discharge outlet.After having been separated from water, the sand is washed with clean water by a spraying nozzle;the dirty water returns to the tank and the washed sand is lifted by the screw. At the first starting, before the grit is lifted and evacuated outside the machine, the solid materialsmust begin settling down to form a bed of grit.When a sufficiently thick bed of grit is formed, the equipment begins evacuating the solid material(grit).Technical data1.1 Waste water delivery to the grit separator :m³/h (*)1.2 Suspended solids :% (*)1.3 Size of the suspended solids to be separated :micron >2001.4 Channel width :mm. (*)1.5 Slope :° 20°1.6 Length of the channel or discharge elevation :mm. (*)1.7 Scrapers stroke :mm. 1601.8 Scrapers lift :mm. 801.9 Number of cycles per minute :no. 12(*) to be advised when asking for a quotation