Clarifiers

Our range of Circular Clarifiers is preferred amidst our global clientele as they require less maintenance, sludge removal is faster and higher removal efficiencies can be obtained. In circular sedimentation tanks, the clarifier mechanism has sludge scrapers attached to a rotating arm scraping the sludge towards a central hopper. In rectangular clarifiers, scrapers are carried trough or hopper at the influent end of the tank. Sedimentation tank scraper mechanisms may take different forms depending on whether the mechanisms are for primary, secondary or tertiary treatment. In circular clarification tanks, the equipment may be of the peripheral drive type, fixed bridge or fixed half bridge (cage drive). In rectangular clarification tanks the mechanism may be of the chain and flight type or have scrapers and scum removal equipment suspended from a traveling bridge. We offer the following three types of clarifiers:

• Primary tank

• Secondary tanks

• Tertiary tanks

Primary Tanks

• After coarse solids have been eliminated and grit removed from the sewage stream, the primary process begins

• In the sedimentation tank the solids are settled out to be removed by mechanically driven scrapers for further displacement

• Scraper mechanisms for primary tanks will also be fitted with surface scum removal equipment to remove floating matter, scum and grease

• Approximately 65% of organic solids and 35% of the BOD in the sewage is removed in the primary process

• From the primary settling tank, the liquid goes through an aeration and or bio filtration process before entering the secondary tank

Secondary Tank

• Following the primary settling phase and the biological treatment stage, secondary sedimentation takes place

• This process separates mixed liquid suspended solids (MLSS) or humus sludge from the purified effluent stream

• Secondary tanks may be fitted with scraper blades as for primary tanks or can be of the suction tube type as illustrated below

• Secondary mechanisms are also normally fitted with scum skimming systems

Tertiary Tank

• These tanks may be fitted with any of the above scraper types or simple sweeper chains. Scum skimming is usually omitted

We have in store for our clients a wide range of Lamella Plate Separator (Inclined Plate Settler) that consists of two main components, the upper tank containing the lamella plates inclined at 55° and the lower conical or cylindrical sludge tank.

Specifications:

• The feed for the IPS enters through vertical chambers on either side of the lamella packs and passes into each plate gap through slotted feed ports

• Clarification takes place above the suspension inlet so there is no mixing of the clarified fluid with the incoming feed

• Above each pack is a full-length overflow launder fitted with throttling holes to create a slight hydraulic back pressure on the incoming feed stream

• This method of feed control guarantees equal distribution to all lamella chambers with minimum turbulence at the entry points

• The solids settle onto and slide down each lamella plate to the sludge tank where the solids are further thickened and compressed with the assistance of the raking system

Advantages:

• Heavy duty construction of tank, sludge hopper and lamella plate packs, as well as the rake system

• Rake lifting mechanism as option.

• Positioning of specifically designed feed ports for optimum ratio between clarification and thickening area

• Wide spacing of lamella plates to handle high density feed pulps and coarse solid particles

• No short-circuiting or surface turbulence

• Integrated flocculator with variable speed stirrer

• Lower installation costs

• Delivered as one-piece unit or in prefabricated sections

• Smaller foundations

• Less floor space

• Square outline for easier planning and construction

• Flexibility for plant changes or extensions

• Can be installed in any system

• Easy to relocate to adapt to process changes

• Simplified in-plant installation

• Shorter pipe work runs.

• High level installation for gravity feed to downstream processes

• Easier supervision

• Small internal volume and surface area

• Easily insulated against heat loss or toxic fume emissions

• Evaporative losses are minimized

• Simple construction of sheet steel and standard profiles

• Special materials and coatings can easily be incorporated

• Easy to maintain