Primary Treatment

Primary clarification is the physical treatment process of removing solids prior to treat the effluent in upstream of secondary treatment, tertiary treatment and advance membrane system. It is the most cost effective way to remove these solids after basic screening. Process water enters the clarifier tank and floatable solids (scum) are removed from the surface by skimmers while settleable solids (sludge) are collected on the bottom by a rake and removed via a sludge removal system. Effluent destined for biological treatment leaves the clarifier over a weir. The expected range for percent removal in a primary clarifier is 90%-95% settleable solids, 40%-60% suspended solids, and 25%-50% total COD and BOD.

With help of coagulant and flocculants, suspended solid can be converted in to sludge and increase the consistency of solids in sludge.

Fluid Sep Technologies offers both conventional and advanced clarification and sedimentation technologies with proven design of quality equipment and dosing methods in effective and small foot print to minimize the civil work and area accommodation. Generally below mechanism are wildly use for primary treatment

Primary clarifier.

Primary treatment removes material that will either float or readily settle out by gravity. It includes the physical processes of screening, comminution, grit removal, and sedimentation. Screens are made of long, closely spaced, narrow metal bars. They block floating debris such as wood, rags, and other bulky objects that could clog pipes or pumps. In modern plants the screens are cleaned mechanically, and the material is promptly disposed of by burial on the plant grounds. A comminutor may be used to grind and shred debris that passes through the screens. The shredded material is removed later by sedimentation or flotation processes.


Influent flow is mixed with previously settled solids within the draft tube. Gentle mixing within the reaction well promotes agglomeration of floc particles and/or chemical precipitates. The aggregated solids settle out more rapidly in the clarification area. Even better clarity is achieved when particles become enmeshed in a sludge blanket layer. Rotating sludge scrapers transport settled solids to the center of the basin for removal. Clarified overflow is removed through a radial launder system that draws water from the entire surface area to prevent solids carryover caused by uneven velocity currents. For high upflowrates, tube settlers can be added to increase the effectiveness of gravity sedimentation.

Tube Settler.

Tube settlers and parallel plates increase the settling capacity of circular clarifiers and/or rectangular sedimentation basins by reducing the vertical distance a floc particle must settle before agglomerating to form larger particles.
Tube settlers use multiple tubular channels sloped at an angle of 60° and adjacent to each other, which combine to form an increased effective settling area. This provides for a particle settling depth that is significantly less than the settling depth of a conventional clarifier, reducing settling times.
Tube settlers capture the settleable fine floc that escapes the clarification zone beneath the tube settlers and allows the larger floc to travel to the tank bottom in a more settleable form. The tube settler’s channel collects solids into a compact mass which promotes the solids to slide down the tube channel.
It can also used for precipitation of reactive silica treatment and Lime soda process to remove hardness.

HMS Technology.

HMS Technology is basically upgraded version of conventional clarifier, and specially designed for sedimentation and precipitation of heavy metal suspended load.In effluent there is heavy load of iron, Zink,, Chrome, which needed to remove before it gets treated from upstream system.
HMS Technology is having three compartment injection tanks, maturation tank and settling zone. Injection tank have two compartment equipped with two agitator. Maturation tank have one agitator and settling zone have one scrapper to avoid sludge jam at bottom part of settling zone.
HMS Technology is basically designed on concept of dense sludge process, in which sludge re-circulation makes the settling process faster and efficient by making bigger flock.

BFC Technology.

BFC Technology clarifier is developed on the base of ballasted floc technology. It has been designed on the concept of coagulant aid.
It is mostly divided in to 4 different compartments Coagulation Tank, Injection Tank, Maturation tank and settling tank with the attachment of sludge recirculation pump and hydro cyclone.
Each compartment is equipped with agitator and settling zone is attached with scrapper mechanism assembly.
Sludge re-circulation pump shall recalculate the sludge from settling zone to Injection tank for the better sedimentation and clarification.
It has benefits of High treatment efficiency, removal rate of turbidity > 90%, Very small footprint compared to, conventional clarifiers; suited forrestricted spaces and easy retrofit, Reduced civil engineering, Flexible: reacts quickly to changing.
raw water quality; providesconsistently high quality effluent, Very short start-up time < 10 minutes, The sludge produced can be thickenedand dewatered easily.
Can be entirely automatedand remotely controlledMinimum equipment to maintain,all easily accessible