equalization process in industries

8/13/2019 Equalization Process in Industries

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Industrial and Hazardous

Waste Management


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Treatment Technologies for IndustrialWastewater


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Selection of the Wastewater TreatmenProcess

1. The selection of a wastewater treatment process or acombination of processes depends upon;

The characteristics of the wastewater The form of the pollutant i.e. Suspended, colloidal, dissolved The biodegradability, and The toxicity of the organic and inorganic components2. The required effluent quality

3. The cost and availability of land for any given wastewatertreatment problems One or more possible solutions Perform cost analysis of each one-to find the most cost

effective


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Pre-Treatment

Coagulationand

Precipitation

Equalization Neutralization

Flotation

Sedimentation

FiltrationSpill Basin


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Equalization

Equalization is the operation aimed at eliminating or

minimizing the problems associated with fluctuations in

wastewater flow and characteristics.


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Purpose of Equalization Basin for Industrialtreatment facilities:

To minimize fluctuations in flow rate to thetreatment plant.

To provide reduction of organic fluctuations in orderto prevent shock loading of biological systems.

Reduce fluctuations in wastewater pH . To minimize chemical requirements necessary for

neutralization. To minimize flow surges to physical-chemical

treatment systems and permit chemical feed rates

compatible with feeding equipment.


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Purpose of Equalization Basin for Industrialtreatment facilities:

To provide continuous feed to biological systems overperiods when the manufacturing plant is notoperating.

To provide capacity for controlled discharge ofwastes to municipal systems in order to distributewaste loads more evenly.

To prevent high concentration of toxic materials fromentering the biological treatment plant .


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Classification of Equalization Operations

Flow Equalization (elimination or dampening ofwastewater flow variations)

Concentration Equalization (dampening ofconcentration fluctuations in wastewater)

Flow and Concentration Equalization


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Classification of Equalization Operations

Equalization may be either online or offline as shownin figure below:


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Equalization

Mixing To ensure adequate equalization and to prevent

settleable solids from depositing in the basin Reduction in BOD may be achieved through mixing and

aerationMethods Distribution of inlet flow and baffling Turbine mixing

Diffused air aeration Mechanical aeration Submerged mixers


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Flow Equalization


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Flow EqualizationPrinciple Design Parameter: Size and type of basin varies with quantity of waste

and the variability of the wastewater stream


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Flow Equalization

Design Consideration

Q in Q out

Q in= Q out

Constant Volume


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Flow Equalization

Design Consideration

Q in Q out

Q in= VariableQ out = Constant

Variable Volume

High le vel

Low level


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Flow Equalization


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Equalization

Design Consideration The equalization basin may be sized to restrict the

discharge to its maximum concentration

commensurate with the maximum permissibledischarge from subsequent units.

Example, If the maximum effluent from an activatedsludge unit is 50 mg/l BOD5.the maximum effluentfrom the equalization basin may be computes andthereby provide a basis for sizing the unit.


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Steps for Finding Capacity of Equalization Basin(Concentration Equalization )

1. Calculate the Wastewater volumes entering theequalization tank during each time interval

2. Calculate Wastewater volumes pumping out from theequalization tank

3. Calculate cumulative influent volume4. Calculate the change in storage during each interval.5. Calculate the cumulative change in storage from a

interval where tank is near to empty6. The effect of flow equalization of BOD mass loading

rate:7. The necessary computations will start from the interval

when the tank is empty.


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Concentration Equalization

Q inBOD in

V start

BOD start

V endBOD end

Q outBOD out

Mass- Balance: Input = Output(Q in * BOD in) +(V start * BOD start )= (Q out * BOD out ) +(V end * BOD end )


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Concentration Equalization

Numerical

equalization process in industries

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