40692328 Trickling Filter

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Presented by

Pradeep.H

Co-ordinated by Dr. Prem raj pushpakaran

Asst.Professor

School of Biotechnolgy



Clarifier

General overview of waste water treatment

Secondary Sludge

Primary Sludge

Clarifier

Raw Wastewater Influent

PRIMARY

DISINFECTION

BiologicalTreatment

System

SECONDARY

Clean Wastewater EffluentDischarge to Receiving Waters

Preliminary Residuals

(i.e., grit, rags, etc.)

A

B

C

Wastewater TreatmentResiduals

BiosolidsProcessing

and Disposal

(e.g., attached-grwothSuspended-Growth,Constructed Wetland, etc.)

Clarifier

PRELIMINARY

Usually to Landfill



Introduction

y Waste refers to unwanted residues that are usually perceived of

negative value

y Waste cause hazards to human health, harm to living resources

and ecological systems, damage to structures and amenities or

that interfere with the legitimate uses of the environment.

y Waste management becomes significant.

y Biochemical wastes include organic wastes,Industrial wastes,

Agricultural wastes etc.



THE MAIN OBJECTIVE of any waste treatment system is removal of

organic and inorganic impurities from water.

Insoluble: By physical separation.

Soluble: 1. Inorganic - chemical treatment.

2. Organic - Biochemical treatment.

The basic reaction in the biochemical operation is:Organic waste + living microorganisms + Oxygen C02 + H20 + more

organisms

This reaction can be carried out in different reactors and the processes are

classified as: Aerobic digestion.

Activated sludge process.

Anaerobic digestion.

Trickling filters.





Trickling filter systemThe components of a complete trickling

filter system are: fundamentalcomponents:

A bed of filter medium upon which a

layer of microbial slime is promoted and

developed.

An enclosure or a container whichhouses the bed of filter medium.

A system for distributing the flow of

wastewater over the filter medium.

A system for removing and disposing of

any sludge from the treated effluent.

The treatment of sewage or other

wastewater with trickling filters is

among the oldest and most well

characterized treatment technologies.



Biological wastewater (WW) treatmenty To remove the suspended solids & the dissolved

organic load from the WW by using microbialpopulations.

y The microorganisms are responsible fory degradation of the organic matter

y they can be classified intoy aerobic (require oxygen for their metabolism)

y anaerobic (grow in absence of oxygen)y facultative (can proliferate either in absence or presence of oxygen).



Biological wastewater (WW) treatmenty If the micro-organisms are suspended in the WW during

biological operationy suspended growth processes

y Recycling of settled biomass is required.

y While the micro-organisms that are attached to a surfaceover which they growy attached growth processes

y The biomass attached to media (ex. rock, plastic, wood)y Recycling of settled biomass is not required.



Attached Growth Process What can this process do?

1. Remove Nutrient

2. Remove dissolved organic solids

3. Remove suspended organic solids

4. Remove suspended solids





Attached Growth Process

y Trickling filter (TF)y Rotating biological contactor (RBC)







Trickling Filter Process



Design considerationy Influent wastewater characteristics

y Degree of treatment anticipated (BOD & TSS removal).

y Temperature range of applied wastewater

y

Pretreatment processesy T ype of filter media

y Recirculation rate

y Hydraulic and organic loadings applied to the filter

y Underdrainage and ventilation systems



Trickling Filter (TF)- side viewy TF consists of:

y A rotating arm that sprays wastewater over a filtermedium.

y Filter medium: rocks, plastic, orother material.

y The water is collected at thebottom of the filter for furthertreatment.

Wastewater

rotating distributor arms

Packing

media

Underdrain



Design consideration - Pretreatment

y Trickling filters shall be preceded by primary clarifiersequipped with scum and grease collecting devices, or othersuitable pretreatment facilities.

y If fine screening is provided the screen size shall have from0.03 to 0.06 inch openings.

y Bar screens are not suitable as the sole means of primary treatment.



Filter mediay Crushed rock

y Durable & insoluble

y Locally availabley But, reduce the void spaces for passage of air

y Less surface area per volume for biological growth

y Plastic mediay Random packing media

y Modular packing media





Design consideration - Filter mediaThe ideal filter packing is material that

y has a high surface area per unit of volume

y is low in costy has a high durability

y has a high enough porosity so that clogging is

minimizedy provides good air circulation



Flow Diagram for Trickling Filters

R ec cle

Primar

clarifier Tric li

filter

Fi al

clarifier

Waste

sl e

Fi al

effl e tI fl e t

Q

Qr

Recir cul tion= A portion of the TF effluent recycled through the filter

Recir cul tion r tio (R) = returned flow (Qr)/ influent flow (Q)



Trickling Filter Process



Design consideration - Recirculation

y Why is recirculation required?

y maintain constant wetting rate

y dilute toxic wastes

y increase air flowy recirculation flow dilutes the strength of raw

wastewater & allows untreated wastewater to bepasses through the filter more than once.

y A common range for recirculation ratioy 0.5~3.0







Ventilation systemsy In TF system,

y Air is supplied by natural draft or forced draft fan.

y The forced draft fans have been applied in order to providethe adequate oxygen.







Single stage

PC SCTF

PC SCTF

PC SCTF

a.

b.

c.



Two stage

PC SCTF

PC SCTF

TF

TF SC

PC SCTFTF SC











Advantages of Trickling filtration plant y Simple and reliable process that is suitable in areas where large tracts of land

are not available for a WSP treatment systemy Effective in treating high concentrations of organic material depending on the

type of media used;

y Very efficient in removal of ammonia from wastewater;

y Appropriate for small- to medium-sized communities

y

With the introduction of plastic filter media to replace the rock media, speedcontrol, and more reliable rotary distributor mechanisms, the performance of trickling filters has been greatly enhanced.

y Ability to handle and recover from shock loads

y Relatively low power requirements; They require power for pumping only anddo not need large power-hungry aeration blowers. From motor-driven rotary

distributors are powered by fractional horsepower electric motors.y They produce less sludge than suspended-growth systems. The sludge tends to

settle well because it is compact and heavy.



Dis v t es f rickli filtr ti l t

y Additional treatment may be needed for the effluent to meet strict dischargestandards;

y generates sludge that must be treated and disposed of;

y

Regular operators attention is needed;y Relatively high incidence of clogging;

y Relatively low loadings required depending on the media;

y Limited flexibility and control in comparison with activated sludge processes.They require high maintenance costs of rotary distributor center mechanisms. Any maintenance service for the rotary distribution mechanism would require

a crane and complete removal of the rotary distributor mechanism, guy rods,and arms.



40692328 Trickling Filter

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