Sludge Thickening System

Wastewater treatment plants commonly use thickening devices to increase the solids concentration at the end of a particular process step within the activated sludge process. Thickening of sludge increases its solids content and reduces the volume of free water thereby minimizing the unit load on downstream processes such as digestion and dewatering.

The most commonly used thickening processes include gravity thickening, dissolved air flotation, and rotary drum thickening. Centrifuge thickening is also becoming more common. The type of thickening selected is usually determined by the size of a wastewater plant, its physical constraints and the downstream process.

We can offer gravity thickening, dissolved air flotation (DAF) thickening, centrifugal thickening, and rotary drum thickening depending upon the process application & space availability.

Industrial Waste Water Treatment Technology

1. Clarifier

            A. Circular Clarifier

Circular Clarifier are the most common type of sedimentation basin used for separating suspended solids from liquids in the treatment of water, sewage, Industrial waste and industrial process.

Column  Mounted (C) Type and Traction driven (T) type Classifiers mechanism for various applications. These operate on the common principle of moving settled solids to the center of principle of moving settled solids to the centre of the tank for removal, and differ principally in the method used to support and drive the rotating sludge removal arms.

Classifiers are designed to handle variety of applications & flows and clarifier includes scum skimming device to remove the floating material.

Primary  Clarifiers.

Secondary  Clarifiers.

White  Liquid Clarifiers & Green Liquor Clarifiers for Pulp & Paper Industries.

Circular Clarifier are the most common type of sedimentation basin used for separating suspended solids from liquids in the treatment of water, sewage, Industrial waste and industrial process.

Column  Mounted (C) Type and Traction driven (T) type Classifiers mechanism for various applications. These operate on the common principle of moving settled solids to the center of principle of moving settled solids to the centre of the tank for removal, and differ principally in the method used to support and drive the rotating sludge removal arms.

Classifiers are designed to handle variety of applications & flows and clarifier includes scum skimming device to remove the floating material.

Primary  Clarifiers.

Secondary  Clarifiers.

White  Liquid Clarifiers & Green Liquor Clarifiers for Pulp & Paper Industries.

Vikas Clarifier Mechanism

Vikas Clarifiers are extensively used for continuous mechanical removal of settle able solids from wastes. These can be either Bridge or Centre column supported. The recommended slope is 1:12 at the bottom of the clarifier tank for efficient removal of sludge. The sludge is scrapped from the bottom of the tank by rotating scrapper arm.

VIKAS  Clarifier comprises of the following:

1.Vikas    Clarifier drive unit consisting of worm and worm wheel gear unit connected to standard gear box by means of sprocket and chain arrangement and the gear box connected directly to motor mounted on MS fabricated base frame.

2. Superstructure comprising of steel structural bridge spanning the entire diameter of the tank. The drive unit is fixed at the centre of the bridge and the bridge is designed to take the static and dynamic load of the drive unit. Necessary chequered  plate and hand rails is provided on the bridge so that it can be used as walkway to have access to the drive at the centre.

3. Two structural steel rake arms are connected to the centre shaft. The rake arms are provided with blades and adjustable brass/neoprene squeezes to rake the tank bottom twice per revolution.

4. The bottom of the shaft rests on guide bearing fixed to tank cone. Suitable cone scrappers are provided.

5. Feed well of suitable diameter is fixed to the bridge is also provided to introduce the feed into the clarifier.

6. Necessary weir plates along with fixing bolts to be fixed to the outlet launder can also be provided on request.

7. Floating scum scrapper with scum box, high torque switch can also be provided on special request.

8. The skimming mechanism, if required, can be provided by us. Generally, this mechanism is required to remove floating debris, solids, which floats on effluent surface.

B. Dissolved Air Flotation (DAF) Systems

                    Dissolve Air Floatations

Vikas Dissolved Air Flotation Clarifier is designed for the removal of suspended solids or water immiscible liquids from process or wastewater to produce an effluent of high clarity and free of objectionable particles or liquid. Dissolved air flotation is best applied to remove materials that normally settle slowly, persist by remaining in suspension, or have a tendency to float.

Algae Removal

Automotive Industry

Bakery Waste

Ballast Water


Chemical Processing Plants

Fiber Recovery

Heavy Metal Recovery


Meat Packing


Potato Processing

Poultry Processing

Prepared Foods

Pulp and Paper Mills

Slaughter House

Tank and Truck Cleaning




Vegetable Oil

How does it work?

Vikas Dissolved Air Flotation (DAF) is a process for the removal of fine suspended material from an aqueous suspension. The term "flotation" indicates something floated on or at the surface of a liquid.

The DAF provides the energy for effective flotation in the form of extremely fine air bubbles, which become attached to the suspended material to be removed. This attachment of nano  bubbles to the particle "reduces" the density of the particle resulting in increased buoyancy, thus effecting flotation. Chemical conditioning is often used to increase the effectiveness of the dissolved air flotation process.

The most reliable and positive method of producing bubbles of the proper size is to dissolve air into water under pressure and to then reduce the pressure of the solution. As the pressure is reduced, the air comes out of solution in the form of micro nano bubbles.


Wastewater is pretreated with chemicals.

Treated influent is fed to DAF unit.

Recycle is drawn off effluent line and is sent through the air dissolving system and then sent back into the DAF.

Air is released from the recycle flow and the bubbles help to float solids in the DAF tank.

Float is skimmed from the top of the tank.

Clear effluent flows out of the unit.

Clarification of a wastewater stream

Reduction of TSS, COD, and BOD to meet effluent discharge limits

Recovery of suspended material

Reclaiming water for reuse

Thickening of slurries and sludges

Minimal operator attention

Low maintenance time and expense

A well-built machine offering long equipment life



Establish influent and required effluent conditions as accurately as possible

Contact us to assist in making a preliminary selection

Perform lab and scale testing if necessary

Make final selection

Other considerations:

What is immediately upstream and downstream of the DAF?

What is most important: floated solids concentration, effluent clarity, capital or operating cost, etc.?

What have you tried before? Why did/didn't it work?

What materials of construction are acceptable? What are not?

Do you need auxiliary equipment, chemical pretreatment, for example?

Do you need any instrumentation or controls?

Do you have any standard specifications?

There are many factors affecting the operation of a clarification process. Among these are chemical pretreatment; power, water, air, or other utilities; operator attention; cleaning requirements; and maintenance needs. All of these should be considered when selecting a wastewater clarification system.

Effluent dosed with Alum/Polyelectrolyte from flocculation tank is fed into coagulation tube (feed well) situated at the centre of DAF unit. Coagulation tube is a vertical cylinder suspended in the centre of the tank where the flocculated effluent enters tangentially to ensure intimate mixing of the flocculated solids with the micro bubbles which are generated due to depressurisation of recycled effluent (which is also fed tangentially).

When  the mixture of air & solid reach top of coagulation tube, the centrifugal force tends to throw air/solids horizontally towards periphery of the tank & move upwards & outwards to form a blanket of skimming (froth). This accumulated skimming which floats on the top is continuously scraped from the surface by the scraper arm into the scum box.

DAF separation principle is based on the fact that air is soluble is liquid in direct proportion to the pressure applied. The treated effluent is recycled to the saturation vessel by means of high pressure recycle pump where plant air is injected which ensures saturation of this liquid with air. This saturated liquid is depressurised through a valve located on the discharge line of the saturation vessel. Which is connected to the coagulation tube. When the pressure is released the air dissolved under pressure comes out of the solution in the form of minute bubbles. These minute bubbles get attached to the flocculated effluent & thus forming solids with combined specific gravity less than the effluent, which finally floats to the surface.


C. Horizontal Clarifier

3. Pulsuation Dampner

4. Sludge Thickening System


                 Roto Drum Sludge Thickner

  Hose Pump or Tube Pump

  Pumping Solutions for liquid handling

 Vikas hose pumps and tube pumps are the ideal solution for pumping liquids and              dosing chemicals. Ranging from pumps to the world’s largest hose and Tube pumps used in very  heavy industrial applications.

Vikas hose and tube pumps are used in many industries including: water and wastewater, mining, food & beverage, chemical, pharmaceuticals, printing and packaging.

Vikas tube and hose pumps can pump abrasive, highly corrosive, viscous, high density and shear sensitive products.

Applications of hose and tube pumps

Hose pumps and tube pumps can be found in a large selection of industries as they provide many solutions to fluid transfer and dosing applications. Often found in water and wastewater applications, hose pumps are able to handle abrasive fluid with a high solid content. The accurate dosing capability also makes the hose pump the perfect all round pumping solution.

The Vikas heavy duty hose or tube pump is excellent choice for mining applications when dealing with froth flotation systems or other slurry transfer requirements.

Vikas Hose or tube pumps offer accurate and programmable dosing of pharmaceuticals and chemicals, as well as in industrial printing and packaging. Accurate dosing and repeatability make the tube pump the perfect addition to your manufacturing plant or laboratory.

Due to the design of a Vikas hose pump or tube pump there is no chance of contamination from outside sources. This is because the fluid being pumped is totally contained within the hose or tube. The low shear pumping action means liquids with high solid contents or containing live cultures can be pumped. This makes the Vikas hose pump the most hygienic and efficient pump for food and beverage products.

Features and benefits of Vikas Tube or Hose pumps

Vikas Hose or tube pumps provide excellent problem solving pumping solutions especially when the product being pumped is particularly abrasive, corrosive or viscous. Their lack of valves, seals and glands makes them inexpensive to maintain the only maintenance item is the hose or tube. Vikas Hose or tube pumps also have a gentle pumping action, ideal for shear sensitive polymers and fragile cell cultures. Lastly, the only part of the pump in contact with the fluid being pumped is the interior of the tube or hose, making it easy to sterilise and clean the inside surfaces of the pump.

Seal-less design

Vikas Hose or tube pumps have no seals avoiding issues such as leaks of corrosive chemicals and ongoing maintenance.

Low maintenance costs

The only replacement part is the hose or tube a relatively low cost item that can be easily changed in a short time.

Dry running and self-priming

Vikas Hose or tube pumps do not require pumped fluid to be continually present pumps can run dry, without costly downtime or repairs. The recovery of the hose or tube creates a powerful self-priming action and allows the pumps to move liquids containing entrapped air or that can off gas.

Gentle pumping action

Vikas Hose or tube pumps have a gentle, low shear pumping action, ideal for shear sensitive products including flocculants and broths

High suction lift

The powerful suction provided by the recovery of a re-enforced hose gives hose pumps suction lift capabilities up to 9.5m of water.


Abrasion resistant

Hose life is not related to a product’s abrasive qualities. The hose only fails due to fatigue or chemical action.

Solids handling

Vikas hose pumps can pump compressible slurries containing up to 80% inorganic solids or 15% organic sludge.


Vikas Hose or tube pumps are reversible and can be used to empty lines or clear blockages

No slip

The pumps have no internal backflow giving accurate dosing without slip

Accurate dosing

The pumps are accurate in dosing; they have a repeatability of ±1% and metering capabilities of ±5%.


The VP flange is certified to EHEDG standards for use in the food, beverages and pharmaceutical industry, plus other sanitary related applications.

Hose pumps Higher pressure Vikas Hose or tube pumps which can typically operate against up to 16 bar in continue service, use shoes (rollers only used on low pressure types) and have casings filled with lubricant to prevent abrasion of the exterior of the pump tube and to aid in the dissipation of heat, and use reinforced tubes, often called "hoses". This class of pump is often called a "hose pump". The hoses in a hose pump are typically reinforced, resulting in a very thick wall. For a given ID the hoses have much bigger OD than tubing for the roller pump. This thicker wall, combined with a stiffer material typically used in the hoses make the forces necessary to occlude the hose much greater than for the tubing. This results in a bigger and slower pump (up to 150/200 RPM) and motor for a given flow rate with the hose pump than the roller pump, consuming more energy to run. The biggest advantage with the hose pumps over the roller pumps is the high operating pressure of up to 16 bars.

With rollers max pressure can arrive up to 12 Bar without any problem. If the high operating pressure is not required, a tubing pump is a better option than a hose pump if the pumped media is not abrasive. With recent advances made in the tubing technology for pressure, life and chemical compatibility, as well as the higher flow rate ranges, the advantages that hose pumps had over roller pumps continues to erode. 3.3.2: Tube pumps Lower pressure peristaltic pumps typically have dry casings and use rollers along with non-reinforced, extruded tubing. This class of pump is sometimes called a "tube pump" or "tubing pump".

These pumps employ rollers to squeeze the tube. Except for the 360 degree eccentric pump design as described below, these pumps have a minimum of 2 rollers 180 degrees apart, and may have as many as 8, or even 12 rollers. Increasing the number of rollers increase the frequency of the pumped fluid at the outlet, thereby decreasing the amplitude of pulsing. The downside to increasing number of rollers it that it proportionately increases number of squeezes, or occlusions, on the tubing for a given cumulative flow through that tube, thereby reducing the tubing life.

Hose Pump Tubing:  Theoretical Flow Rates, Pressure Ratings, Calculations, Formulations, Comparative Descriptions:

The information presented on this page is a continuation of advanced technical details on Hose pump or Tube  Pump Tubing.  Select from the links below to "jump" to a specific section on the page.

  • Theoretical Flow Rate Calculations
  • Pressure Ratings
  • Calculation of Working Pressure
  • Popular Tubing Formulations for Markets
  • Comparative Descriptions

Theoretical Flow Rate Calculations

The information below can be used to calculate theoretical flow rate of a pumping system or to determine tubing ID required for a desired flow rate.

Theoretical flow rate
in cc's/minute




tubing length that will be
occluded by pump rollers


number of rollers
on the rotor


rpm's of
the pump









Tubing ID (inches)


"V" = Volume of Occluded tubing(cc's/inch)



Tubing ID (inches)


"V" = Volume of Occluded tubing (cc's/inch)










































 Pressure Ratings for Peristaltic Pump Tubings:

Tests have shown that as the back pressure experienced by a pumping system approaches the working pressure ratings, tubing life is reduced. Working pressures are calculated at a 1:5  ratio relative to burst pressure.

Inside Diameter

Outside Diameter

Wall Thickness

Maximum Suggested Working Pressure of Pumping System at Room Temperature (73°F)


























































Calculation of Working Pressure

This information can be used to calculate the working pressure of a specific tubing. Using the pressure ratings for hose pump tubings chart and the calculation of working pressure chart, multiply the appropriate value shown times (x) the number provided below. For example: 1/16 inch I.D. Tygon  B-44-3 tubing would be 70 psi x 1.43 = 100.10 psi working pressure.


Tygon  LFL

Multiply Value Shown Times (x)


Tygon  R-3603

Multiply Value Shown Times (x)


Versilo  E-1000

Multiply Value Shown Times (x)


Tygon  F-4040-A

Multiply Value Shown Times (x)


Versilon 2001

Multiply Value Shown Times (x)


Tygon  XL-60

Multiply Value Shown Times (x)


Versilon F-5500-A

Multiply Value Shown Times (x)


Tygon  A-60-G

Multiply Value Shown Times (x)


Tygon  A-60-F

Multiply Value Shown Times (x)


Tygon S-50-HL

Multiply Value Shown Times (x)


PharMed  BPT

Multiply Value Shown Times (x)


Tygon B-44-3

Multiply Value Shown Times (x)


Versilic SPX-50

Multiply Value Shown Times (x)



Tubing Formulations for General Markets

The chart below details our most popular tube pump tubing formulations for general market categories.



ceutical/ Cosmetic






Tygon LFL




Tygon R-3603





Versilon E-1000







Tygon F4040-A






Versilon 2001





Tygoprene XL-60





Versilon F-5500-A






Tygon A60-G







Tygon A-60-F







Tygon S-50-HL





Phar Med BPT





Tygon B-44-3






Versilic SPX-50



*Saint-Gobain Autoanalyzer tubing - Outstanding flow characteristics and dimensional tolerances provide accuracy and reproducibility of delivery rates.  Available  in a wide variety of application specific formulations.
Hose Pump Tubings, Comparative Descriptions:


Clear and flexible, provides the longest life in peristaltic pumps where other clear, plastic tubings fail. Ideally suited for bulk transfer applications. Low spallation. Meets USP Class VI and FDA criteria.


Consistently unaffected by virtually all inorganic chemicals. Tygon-3603 provides the laboratory pump user with repeatedly reliable results. Low spallation. Meets FDA criteria.


An extremely soft and flexible tubing, Tygon-1000 offers long life and minimal resistance to compression in low torque peristaltic pumps. Meets FDA and NSF 51 criteria


Maintains pumpability and resists cracking when transporting fuels, lubricants and other hydrocarbon based products.


Provides low compression set properties of a thermoset rubber in a clear, flexible tubing. Meets FDA criteria.

Tygoprene XL-60

Designed specifically for use in peristaltic pump applications and provides flexibility and long life. Meets FDA and NSF 51 criteria



Provides unequalled chemical and temperature resistance to perform in the most severe environments.


Exhibits extremely high flexural fatigue characteristics, excellent chemical resistance and an ability to handle a wide temperature range. An all-around top performer for numerous industrial peristaltic pump applications 


A long flex life tubing that is unaffected by wide temperature variations; formulated specifically for hot food and beverage processing and dispensing. Meets FDA, NSF 51, and 3-A Sanitary Standards for Plastics Criteria.


Initially developed for open heart surgical procedures, this tubing represents the standard of excellence in critical clinical and biological applications. Crystal clear, non-toxic and non-hemolytic. Low spallation. Meets USP Class VI criteria. Fully tested to ISO 10993 standards.


Low spallation, low gas permeability and an unequaled flex life will minimize the risk of fluid exposure in sensitive applications.  Biocompatible, non-toxic and non-hemolytic, an excellent choice in pharmaceutical processing, tissue and cell culture applications.  Meets FDA, NSF 51 and USP Class VI criteria. Fully tested to ISO 10993 standards.




The most widely specified tubing for use in the handling of food, beverages and dairy products. Tygon B-44-3 tubing meets appropriate FDA, NSF 51, and 3-A Sanitary Standards for Plastics Criteria. Low spallation.


A peroxide cured silicone that provides long life, strength and durability. Meets FDA, NSF 51, 3-A Sanitary Standards for Plastics and USP Class VI criteria. 


Optimization of an activated sludge plant requires the integration of mechanical, operational, and chemical approaches for the most practical overall program. Mechanical problems can include excessive hydraulic loading, insufficient aeration, and short-circuiting. Operational problems may include spills and shock loads, pH shocks, failure to maintain correct mixed liquor concentration, and excessive sludge retention in the clarifier.

Industrial Waste Water Treatment Technology

Industrial Waste Water Treatment

  • Pollutants
  • Removal of insoluble contaminants
  • Removal of soluble contaminants
  • Solid waste handling
  • Environmental regulations 

Many industries use large volumes of water in their manufacturing operations. Because some of this water becomes contaminated, it requires treatment before discharge

Improvements in determining the effects of industrial waste discharges have led to the adoption of stringent environmental laws, which define the degree of treatment necessary to protect water quality.

Discharge permits, issued under the National Pollutant Discharge Elimination System (NPDES), regulate the amount of pollutants that an industry can return to the water source. The permitted quantities are designed to ensure that other users of the water will have a source that meets their needs, whether these needs are for municipal water supply, industrial or agricultural uses, or fishing and recreation. Consideration is given to the feasibility of removing a pollutant, as well as the natural assimilative capacity of the receiving stream. This assimilative capacity varies with the type and amount of pollutant.

Wastewater treatment plants are designed to convert liquid wastes into an acceptable final effluent and to dispose of solids removed or generated during the process. In most cases, treatment is required for both suspended and dissolved contaminants. Special processes are required for the removal of certain pollutants, such as phosphorus or heavy metals.

Wastewater can be recycled for reuse in plant processes to reduce disposal requirements. This practice also reduces water consumption.


Organic Compounds

The amount of organic material that can be discharged safely is defined by the effect of the material on the dissolved oxygen level in the water. Organisms in the water use the organic matter as a food source. In a biochemical reaction, dissolved oxygen is consumed as the end products of water and carbon dioxide are formed. Atmospheric oxygen can replenish the dissolved oxygen supply, but only at a slow rate. When  the organic load causes oxygen consumption to exceed this resupply, the dissolved oxygen level drops, leading to the death of fish and other aquatic life. Under extreme conditions, when the dissolved oxygen concentration reaches zero, the water may turn black and produce foul odors, such as the "rotten egg" smell of hydrogen sulfide. Organic compounds are normally measured as chemical oxygen demand (COD) or biochemical oxygen demand (BOD).


Nitrogen and phosphorus are essential to the growth of plants and other organisms. However, nitrogen compounds can have the same effect on a water source as carbon-containing organic compounds. Certain organisms use nitrogen as a food source and consume oxygen.

Phosphorus is a concern because of algae blooms that occur in surface waters due to its presence. During the day, algae produce oxygen through photosynthesis, but at night they consume oxygen.


Solids discharged with a waste stream may settle immediately at the discharge point or may remain suspended in the water. Settled solids cover the bottom-dwelling organisms, causing disruptions in population and building a reservoir of oxygen-consuming materials. Suspended solids increase the turbidity of the water, thereby inhibiting light transmittance. Deprived of a light source, photosynthetic organisms die. Some solids can coat fish gills and cause suffocation.

Acids and Alkalies

The natural buffering system of a water source is exhausted by the discharge of acids and alkalies. Aquatic life is affected by the wide swings in pH as well as the destruction of bicarbonate alkalinity levels.


Certain metals are toxic and affect industrial, agricultural, and municipal users of the water source. Metals can cause product quality problems for industrial users. Large quantities of discharged salts necessitate expensive removal by downstream industries using the receiving stream for boiler makeup water.


Various physical methods may be used for the removal of wastewater contaminants that are insoluble in water, such as suspended solids, oil, and grease. Ordinarily, water-soluble contaminants are chemically converted to an insoluble form to allow removal by physical methods. Essentially, biological waste treatment is this conversion of soluble contaminants to insoluble forms.

Gravity Separation

Most waste treatment systems employ a gravity separation step for suspended particle or oil removal.

The settling rate of a particle is defined in terms of "free" versus "hindered" settling. A free settling particle's motion is not affected by that of other particles, the vessel's walls, or turbulent currents. A particle has a hindered settling rate if there is any interference from these effects.

The free settling of a discrete particle in a rising fluid can be described as the resolution of several forces-gravity, the drag exerted on the particle, and the buoyant force as described by Archimedes' principle. The particle's velocity increases until it reaches a terminal velocity as determined by these forces. The terminal velocity is then:


  • v        =         velocity, ft/sec
  • g       =         gravitation constant, ft/sec2


Gravity settling is employed primarily for removal of inorganic suspended solids, such as grit and sand. Therefore, in the approximation of the drag coefficient, it is assumed that particles are spherical. Further, if a Reynolds number of less than 2.0 is assumed, the settling velocity of a discrete particle can be described by Stokes' settling equation:

  • V =

GdP2(rP - rf)


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