Final Project Softcopy

8/14/2019 Final Project Softcopy

1/24

EIILM H-4GREEN MANAGEMENT (TECHNOLOGY)

GUIDED BY:DR. L.R. GUHA

WASTEWATERTREATMENT

Trickling Filter

RUNNERS Group02/04/2009

What is wastewater? List of water treatment technologies. Trickling Filter.

BOD & COD. Merits & Demerits of Trickling Filter. Technologies suitable for

W.B. C program of the Trickling Filter.


2/24

What is wastewater?

We consider wastewater treatment as a water use because it is so interconnected withthe other uses of water. Much of the water used by homes, industries, and businessesmust be treated before it is released back to the environment.

If the term "wastewater treatment" is confusing to you, you might think of it as "sewagetreatment." Nature has an amazing ability to cope with small amounts of water wastesand pollution, but it would be overwhelmed if we didn't treat the billions of gallons ofwastewater and sewage produced every day before releasing it back to the environment.Treatment plants reduce pollutants in wastewater to a level nature can handle.

Wastewater is used water. It includes substances such as human waste, food scraps, oils,soaps and chemicals. In homes, this includes water from sinks, showers, bathtubs,toilets, washing machines and dishwashers. Businesses and industries also contributetheir share of used water that must be cleaned.

Wastewater also includes storm runoff. Although some people assume that the rain thatruns down the street during a storm is fairly clean, it isn't. Harmful substances thatwash off roads, parking lots, and rooftops can harm our rivers and lakes.

The major aim of wastewater treatment is to remove as much of the suspended solids aspossible before the remaining water, called effluent, is discharged back to the

environment. As solid material decays, it uses up oxygen, which is needed by the plantsand animals living in the water.

"Primary treatment" removes about 60 percent of suspended solids from wastewater.This treatment also involves aerating (stirring up) the wastewater, to put oxygen backin. Secondary treatment removes more than 90 percent of suspended solids.


3/24

List of waste water treatment technologies

Activated sludge systems[1] Constructed Soil Filter Advanced Oxidation Process Aerated lagoon Aerobic granular reactor Aerobic treatment system Anaerobic clarigester Anaerobic digestion API oil-water separator Anaerobic lagoon Bead Filter Belt press Bioconversion of biomass to mixed alcohol fuels Bioreactor Bioretention Biorotor Bioroll Biolytix Carbon filtering Cesspit Chlorine disinfection Combined sewer Composting toilet Constructed wetland Dissolved air flotation Distillation

De-salination

Electrocoagulation Electrodeionization

Electrolysis Electro-Fenton process Expanded granular sludge bed digestion Facultative lagoon Fenton's reagent Flocculation & sedimentation Fluidized Bed Biofilter Flotation process Froth flotation Fuzzy Filter Humanure (composting)

Imhoff tank
http://en.wikipedia.org/wiki/Activated_sludgehttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologies#cite_note-0http://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologies#cite_note-0http://en.wikipedia.org/w/index.php?title=Constructed_Soil_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Advanced_Oxidation_Processhttp://en.wikipedia.org/wiki/Aerated_lagoonhttp://en.wikipedia.org/wiki/Aerobic_granular_reactorhttp://en.wikipedia.org/wiki/Aerobic_treatment_systemhttp://en.wikipedia.org/wiki/Anaerobic_clarigesterhttp://en.wikipedia.org/wiki/Anaerobic_digestionhttp://en.wikipedia.org/wiki/API_oil-water_separatorhttp://en.wikipedia.org/wiki/Anaerobic_lagoonhttp://en.wikipedia.org/w/index.php?title=Bead_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Belt_presshttp://en.wikipedia.org/wiki/Bioconversion_of_biomass_to_mixed_alcohol_fuelshttp://en.wikipedia.org/wiki/Bioreactorhttp://en.wikipedia.org/wiki/Bioretentionhttp://en.wikipedia.org/w/index.php?title=Biorotor&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Bioroll&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Biolytix&action=edit&redlink=1http://en.wikipedia.org/wiki/Carbon_filteringhttp://en.wikipedia.org/wiki/Cesspithttp://en.wikipedia.org/w/index.php?title=Chlorine_disinfection&action=edit&redlink=1http://en.wikipedia.org/wiki/Combined_sewerhttp://en.wikipedia.org/wiki/Composting_toilethttp://en.wikipedia.org/wiki/Constructed_wetlandhttp://en.wikipedia.org/wiki/Dissolved_air_flotationhttp://en.wikipedia.org/wiki/Distillationhttp://en.wikipedia.org/wiki/Electrocoagulationhttp://en.wikipedia.org/wiki/Electrodeionizationhttp://en.wikipedia.org/wiki/Electrolysishttp://en.wikipedia.org/w/index.php?title=Electro-Fenton_process&action=edit&redlink=1http://en.wikipedia.org/wiki/Expanded_granular_sludge_bed_digestionhttp://en.wikipedia.org/w/index.php?title=Facultative_lagoon&action=edit&redlink=1http://en.wikipedia.org/wiki/Fenton's_reagenthttp://en.wikipedia.org/wiki/Flocculationhttp://en.wikipedia.org/wiki/Sedimentationhttp://en.wikipedia.org/w/index.php?title=Fluidized_Bed_Biofilter&action=edit&redlink=1http://en.wikipedia.org/wiki/Flotation_processhttp://en.wikipedia.org/wiki/Froth_flotationhttp://en.wikipedia.org/w/index.php?title=Fuzzy_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Humanurehttp://en.wikipedia.org/wiki/Imhoff_tankhttp://en.wikipedia.org/wiki/Activated_sludgehttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologies#cite_note-0http://en.wikipedia.org/w/index.php?title=Constructed_Soil_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Advanced_Oxidation_Processhttp://en.wikipedia.org/wiki/Aerated_lagoonhttp://en.wikipedia.org/wiki/Aerobic_granular_reactorhttp://en.wikipedia.org/wiki/Aerobic_treatment_systemhttp://en.wikipedia.org/wiki/Anaerobic_clarigesterhttp://en.wikipedia.org/wiki/Anaerobic_digestionhttp://en.wikipedia.org/wiki/API_oil-water_separatorhttp://en.wikipedia.org/wiki/Anaerobic_lagoonhttp://en.wikipedia.org/w/index.php?title=Bead_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Belt_presshttp://en.wikipedia.org/wiki/Bioconversion_of_biomass_to_mixed_alcohol_fuelshttp://en.wikipedia.org/wiki/Bioreactorhttp://en.wikipedia.org/wiki/Bioretentionhttp://en.wikipedia.org/w/index.php?title=Biorotor&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Bioroll&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Biolytix&action=edit&redlink=1http://en.wikipedia.org/wiki/Carbon_filteringhttp://en.wikipedia.org/wiki/Cesspithttp://en.wikipedia.org/w/index.php?title=Chlorine_disinfection&action=edit&redlink=1http://en.wikipedia.org/wiki/Combined_sewerhttp://en.wikipedia.org/wiki/Composting_toilethttp://en.wikipedia.org/wiki/Constructed_wetlandhttp://en.wikipedia.org/wiki/Dissolved_air_flotationhttp://en.wikipedia.org/wiki/Distillationhttp://en.wikipedia.org/wiki/Electrocoagulationhttp://en.wikipedia.org/wiki/Electrodeionizationhttp://en.wikipedia.org/wiki/Electrolysishttp://en.wikipedia.org/w/index.php?title=Electro-Fenton_process&action=edit&redlink=1http://en.wikipedia.org/wiki/Expanded_granular_sludge_bed_digestionhttp://en.wikipedia.org/w/index.php?title=Facultative_lagoon&action=edit&redlink=1http://en.wikipedia.org/wiki/Fenton's_reagenthttp://en.wikipedia.org/wiki/Flocculationhttp://en.wikipedia.org/wiki/Sedimentationhttp://en.wikipedia.org/w/index.php?title=Fluidized_Bed_Biofilter&action=edit&redlink=1http://en.wikipedia.org/wiki/Flotation_processhttp://en.wikipedia.org/wiki/Froth_flotationhttp://en.wikipedia.org/w/index.php?title=Fuzzy_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Humanurehttp://en.wikipedia.org/wiki/Imhoff_tank


4/24

Iodine Ion exchange Living machines Membrane bioreactor Nanotechnology NERV(Natural Endogenous Respiration Vessel) N-Viro Ozone and Ultrasound Parallel plate oil-water separator Recirculating Sand Filter Reed bed Retention basin Reverse osmosis Rotating biological contactor Sand filter Septic tank Sequencing batch reactor Sewage treatment Stabilization pond Submerged aerated filter Treatment pond Trickling filter Ultrafiltration (industrial) Ultraviolet disinfection Upflow anaerobic sludge blanket digestion Upflow Sludge Blanket Filtration (USBF) Wet oxidation
http://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Ion_exchangehttp://en.wikipedia.org/wiki/Living_machineshttp://en.wikipedia.org/wiki/Membrane_bioreactorhttp://en.wikipedia.org/wiki/Nanotechnologyhttp://en.wikipedia.org/wiki/NERVhttp://en.wikipedia.org/w/index.php?title=N-Viro&action=edit&redlink=1http://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/API_oil-water_separatorhttp://en.wikipedia.org/w/index.php?title=Recirculating_Sand_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Reed_bedhttp://en.wikipedia.org/wiki/Retention_basinhttp://en.wikipedia.org/wiki/Reverse_osmosishttp://en.wikipedia.org/wiki/Rotating_biological_contactorhttp://en.wikipedia.org/wiki/Sand_filterhttp://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Sequencing_batch_reactorhttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Stabilization_pondhttp://en.wikipedia.org/w/index.php?title=Submerged_aerated_filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Treatment_pondhttp://en.wikipedia.org/wiki/Trickling_filterhttp://en.wikipedia.org/wiki/Ultrafiltration_(industrial)http://en.wikipedia.org/wiki/Ultraviolet_disinfectionhttp://en.wikipedia.org/wiki/Upflow_anaerobic_sludge_blanket_digestionhttp://en.wikipedia.org/w/index.php?title=Upflow_Sludge_Blanket_Filtration_(USBF)&action=edit&redlink=1http://en.wikipedia.org/wiki/Wet_oxidationhttp://en.wikipedia.org/wiki/Iodinehttp://en.wikipedia.org/wiki/Ion_exchangehttp://en.wikipedia.org/wiki/Living_machineshttp://en.wikipedia.org/wiki/Membrane_bioreactorhttp://en.wikipedia.org/wiki/Nanotechnologyhttp://en.wikipedia.org/wiki/NERVhttp://en.wikipedia.org/w/index.php?title=N-Viro&action=edit&redlink=1http://en.wikipedia.org/wiki/Ozonehttp://en.wikipedia.org/wiki/Ultrasoundhttp://en.wikipedia.org/wiki/API_oil-water_separatorhttp://en.wikipedia.org/w/index.php?title=Recirculating_Sand_Filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Reed_bedhttp://en.wikipedia.org/wiki/Retention_basinhttp://en.wikipedia.org/wiki/Reverse_osmosishttp://en.wikipedia.org/wiki/Rotating_biological_contactorhttp://en.wikipedia.org/wiki/Sand_filterhttp://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Sequencing_batch_reactorhttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Stabilization_pondhttp://en.wikipedia.org/w/index.php?title=Submerged_aerated_filter&action=edit&redlink=1http://en.wikipedia.org/wiki/Treatment_pondhttp://en.wikipedia.org/wiki/Trickling_filterhttp://en.wikipedia.org/wiki/Ultrafiltration_(industrial)http://en.wikipedia.org/wiki/Ultraviolet_disinfectionhttp://en.wikipedia.org/wiki/Upflow_anaerobic_sludge_blanket_digestionhttp://en.wikipedia.org/w/index.php?title=Upflow_Sludge_Blanket_Filtration_(USBF)&action=edit&redlink=1http://en.wikipedia.org/wiki/Wet_oxidation


5/24

Trickling filter

Image 1: A schematic cross-section of the contact face of the bed media in a trickling

filter

A trickling filter consists of a fixed bed of rocks, gravel, slag, polyurethane foam,sphagnum peat moss, or plastic media over which sewage or other wastewater flowsdownward and causes a layer or film ofmicrobial slime to grow, covering the bed ofmedia.Aerobic conditions are maintained by splashing, diffusion, and either by forcedair flowing through the bed or natural convection of air if the filter medium is porous.The process mechanism, or how the removal of waste from the water happens, involvesboth absorption and adsorption of organic compounds within the sewage or otherwastewater by the layer of microbial slime. Diffusion of the wastewater over the mediafurnishes dissolved air, the oxygen which the slime layer requires for thebiochemicaloxidation of the organic compounds and releases carbon dioxide gas, water and otheroxidized end products. As the slime layer thickens, it becomes more difficult for air topenetrate the layer and an inner anaerobic layer is probably formed. This slime layercontinues to build until it eventually sloughs off, breaking off longer growth into thetreated effluent as a sludge that requires subsequent removal and disposal. Typically, atrickling filter is followed by a clarifier or sedimentation tank for the separation andremoval of the sloughing. Other filters utilizing higher-density media such as sand, foamand peat moss do not produce a sludge that must be removed, but require forced airblowers and backwashing or an enclosed anaerobic environment.

The terms trickle filter, trickling biofilter, biofilter, biological filter andbiological trickling filter are often used to refer to a trickling filter.

These systems have also been described as roughing filters, intermittent filters, packedmedia bed filters, alternative septic systems, percolating filters, attached growthprocesses, and fixed film processes.

The treatment of sewage or other wastewater with trickling filters is among the oldestand most well characterized treatment technologies.
http://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Gravelhttp://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Polyurethanehttp://en.wikipedia.org/wiki/Foamhttp://en.wikipedia.org/wiki/Peat_mosshttp://en.wikipedia.org/wiki/Sewagehttp://en.wikipedia.org/wiki/Wastewaterhttp://en.wikipedia.org/wiki/Microbialhttp://en.wiktionary.org/wiki/aerobichttp://en.wikipedia.org/wiki/Absorption_(chemistry)http://en.wikipedia.org/wiki/Adsorptionhttp://en.wikipedia.org/wiki/Organic_compoundshttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Biochemicalhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Effluenthttp://en.wikipedia.org/wiki/File:Trickle_Filter_Cross-section.pnghttp://en.wikipedia.org/wiki/Rock_(geology)http://en.wikipedia.org/wiki/Gravelhttp://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Polyurethanehttp://en.wikipedia.org/wiki/Foamhttp://en.wikipedia.org/wiki/Peat_mosshttp://en.wikipedia.org/wiki/Sewagehttp://en.wikipedia.org/wiki/Wastewaterhttp://en.wikipedia.org/wiki/Microbialhttp://en.wiktionary.org/wiki/aerobichttp://en.wikipedia.org/wiki/Absorption_(chemistry)http://en.wikipedia.org/wiki/Adsorptionhttp://en.wikipedia.org/wiki/Organic_compoundshttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Biochemicalhttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Effluent


6/24

Types

The three basic types of trickle filters are used for:

the treatment of small individual residential or rural sewage large centralized systems for treatment of municipal sewage systems applied to the treatment of industrial wastewater.

Septic system leach field

This is the simplest form of waste liquid disposal system, typically using pipes buried inloose sand or gravel to dissipate the liquid outflow from a septic tank. Liquidpurification is performed by abiofilm which naturally forms as a coating on the sandand gravel in the absorption field and feeds on the dissolved nutrients in the wastestream.

Due to the system being completely buried and generally isolated from the surfaceenvironment, the process of waste breakdown is slow and requires a relatively largesurface area to absorb and process liquid wastes. If too much liquid wastes enter thefield too quickly, the wastes may pass out of the biofilm before waste consumption canoccur, leading to pollution of groundwater.

In order to prolong the life of a leaching field, one method of construction is to build twofields of piping side-by-side, and use a rotating flow valve to direct waste into one fieldat a time, switching between fields every year or two. This allows a period of rest to letthe microorganisms have time to break down the wastes built up in the gravel bed.

In areas where the ground is insufficiently absorptive (fails the percolation test) ahomeowner may be required to construct a mound systemwhich is a special engineeredwaste disposal bed of sand and gravel mounded on the surface of the ground with poorliquids absorption.

Leach field dosing

Generally it is better if the biofilm is permitted a period of time to rest between liquidinfluxes and for the liquids to be evenly distributed through the leaching bed to promotebiofilm growth throughout the pipe network. Typically flows from septic systems areeither small surges (handwashing) or very large surges (clothes washer emptying),

resulting in highly erratic liquid outflow into the field and uneven biofilm growthconcentrating primarily around the field inlet and dropping off in the outer reaches ofthe piping system.

For this reason it is common for engineered mound systems to include an electricallypowered dosing system which consists of a large capacity underground storage tank andlift pump after the septic tank. When the tank fills to a predetermined level, it is emptiedinto the leaching field.

The storage tank collects small outflows such as from handwashing and saves them fordosing when the tank fills from other sources. During this fill period the field is able to

rest continuously. When full, the discharge dose fills out the entire field completely to
http://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Biofilmhttp://en.wikipedia.org/wiki/Percolation_testhttp://en.wikipedia.org/wiki/Mound_systemhttp://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Biofilmhttp://en.wikipedia.org/wiki/Percolation_testhttp://en.wikipedia.org/wiki/Mound_system


7/24

the same degree of flow, every time, promoting an even biofilm growth throughout thesystem.

Dosing systems have maintenance requirements over traditional non-powered surgesystems. The pump and float system can break down and require replacement, and thedosing system also needs electricity. However, the system can be designed so that in theevent of power failure the storage tank overflows to the field operating in the traditionalsurge-flow manner until power is restored or repairs can be done.

Soil Compaction issues

The biofilm is most productive if the absorption field is loosely packed, to permit easyair infiltration down into the biofilm bed. Consequently the land over the leaching fieldis often a restricted area where large vehicles cannot be allowed to drive, because theheavy weight will compact the bed, and potentially cause system failure due to hinderingof biofilm growth.

One method to help prevent compaction of the field is to place a U-shaped cover overgravel trenches in the bed, with a dosing pipe suspended above the bed by the cover.Any weight from above is passed to the sides of the trench keeping the bed directlyunder the cover free from compaction.

Sewage treatment trickle filters

Onsite sewage facilities (OSSF) are recognized as viable, low-cost, long-term,decentralized approaches to sewage treatment if they are planned, designed, installed,operated and maintained properly (USEPA, 1997).

Sewage trickling filters are used in areas not serviced by municipal wastewater

treatment plants (WWTP). They are typically installed in areas where the traditionalseptic tank system are failing, cannot be installed due to site limitations, or whereimproved levels of treatment are required for environmental benefits such as preventingcontamination ofground water or surface water.

Sites with a highwater table, highbedrock, heavyclay, small land area, or which requireminimal site destruction (for example, tree removal) are ideally suited for tricklingfilters.

All varieties of sewage trickling filters have a low and sometimes intermittent powerconsumption. They can be somewhat more expensive than traditional septic tank-leach

field systems, however their use allows for better treatment, a reduction in size ofdisposal area, less excavation, and higher density land development.

Configurations and components

All sewage trickling filter systems share the same fundamentalcomponents:

a septic tank for fermentation and primary settling of solids
http://en.wikipedia.org/wiki/Onsite_sewage_facilitieshttp://en.wikipedia.org/wiki/Decentralizedhttp://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Ground_waterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Water_tablehttp://en.wikipedia.org/wiki/Bedrockhttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Componentshttp://en.wikipedia.org/wiki/Onsite_sewage_facilitieshttp://en.wikipedia.org/wiki/Decentralizedhttp://en.wikipedia.org/wiki/Septic_tankhttp://en.wikipedia.org/wiki/Ground_waterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Water_tablehttp://en.wikipedia.org/wiki/Bedrockhttp://en.wikipedia.org/wiki/Clayhttp://en.wikipedia.org/wiki/Components


8/24

a filter medium upon which beneficial microbes (biomass,biofilm) are promotedand developed

a container which houses the filter medium a distribution system for applying wastewater to be treated to the filter medium a distribution system for disposal of the treated effluent or percolation ponds.

By treating septic tank effluent before it is distributed into the ground, higher treatmentlevels are obtained and smaller disposal means such as leach field, shallow pressuretrench or area beds are required.

Systems can be configured for single-pass use where the treated water is applied to thetrickling filter once before being disposed of, or for multi-pass use where a portion of thetreated water is cycled back to the septic tank and re-treated via a closed-loop. Multi-pass systems result in higher treatment quality and assist in removing Total Nitrogen(TN) levels by promoting nitrification in the aerobic media bed and denitrification in theanaerobic septic tank.

Trickling filters differ primarily in the type of filter media used to house the microbial

colonies. Types of media most commonly used include plastic matrix material, open-cellpolyurethane foam, sphagnum peat moss, recycled tires, clinker, gravel,sand andgeotextiles. Ideal filter medium optimizes surface area for microbial attachment,wastewater retention time, allows air flow, resists plugging and does not degrade. Someresidential systems require forced aeration units which will increase maintenance andoperational costs.

Regulatory approvals

Third-party verification of trickling filters has proven them to be a reliable alternative toseptic systems with increased levels of treatment performance and nitrogen removal.

Typical effluent quality parameters are Biochemical Oxygen Demand (BOD), Totalsuspended solids (TSS), Total Kjeldahl Nitrogen (TKN), and fecal coliforms.

The leading testing facility in the United States is the Massachusetts Alternative SepticSystem Test Center, a program of the Buzzards Bay National Estuary Program. Testingconducted here includes the stringent Environmental Technology Initiative (ETI) wheresystems are tested in triplicate over two years, and the Environmental TechnologyVerification (ETV) program which is funded by the U.S. Environmental ProtectionAgency(EPA) and includes stress testing as well as evaluation ofnitrogen removal over14 months. Systems are approved for installation by local, state and federal regulationsand controls.
http://en.wikipedia.org/wiki/Microbeshttp://en.wikipedia.org/wiki/Biofilmhttp://en.wikipedia.org/wiki/Leach_fieldhttp://en.wikipedia.org/wiki/Closed-loophttp://en.wikipedia.org/wiki/Nitrificationhttp://en.wikipedia.org/wiki/Denitrificationhttp://en.wikipedia.org/wiki/Polyurethanehttp://en.wikipedia.org/wiki/Foamhttp://en.wikipedia.org/wiki/Peat_mosshttp://en.wikipedia.org/wiki/Tireshttp://en.wikipedia.org/wiki/Sandhttp://en.wikipedia.org/wiki/Surface_areahttp://en.wikipedia.org/wiki/Third-party_verificationhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Effluenthttp://en.wikipedia.org/wiki/Biochemical_Oxygen_Demandhttp://en.wikipedia.org/wiki/Total_suspended_solidshttp://en.wikipedia.org/wiki/Total_suspended_solidshttp://en.wikipedia.org/wiki/Total_Kjeldahl_Nitrogenhttp://en.wikipedia.org/wiki/Fecal_coliformshttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Massachusettshttp://en.wikipedia.org/wiki/U.S._Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/U.S._Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Regulationshttp://en.wikipedia.org/wiki/Microbeshttp://en.wikipedia.org/wiki/Biofilmhttp://en.wikipedia.org/wiki/Leach_fieldhttp://en.wikipedia.org/wiki/Closed-loophttp://en.wikipedia.org/wiki/Nitrificationhttp://en.wikipedia.org/wiki/Denitrificationhttp://en.wikipedia.org/wiki/Polyurethanehttp://en.wikipedia.org/wiki/Foamhttp://en.wikipedia.org/wiki/Peat_mosshttp://en.wikipedia.org/wiki/Tireshttp://en.wikipedia.org/wiki/Sandhttp://en.wikipedia.org/wiki/Surface_areahttp://en.wikipedia.org/wiki/Third-party_verificationhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Effluenthttp://en.wikipedia.org/wiki/Biochemical_Oxygen_Demandhttp://en.wikipedia.org/wiki/Total_suspended_solidshttp://en.wikipedia.org/wiki/Total_suspended_solidshttp://en.wikipedia.org/wiki/Total_Kjeldahl_Nitrogenhttp://en.wikipedia.org/wiki/Fecal_coliformshttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/Massachusettshttp://en.wikipedia.org/wiki/U.S._Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/U.S._Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Regulations


9/24

Fig: A typical complete trickling filter system
http://en.wikipedia.org/wiki/File:Trickle_Filter.png


10/24

Industrial wastewater treatment trickle filters

Wastewaters from a variety of industrial processes have been treated in trickling filters.Such industrial wastewater trickling filters consist of two types:

Large tanks or concrete enclosures filled with plastic packing or other media.

Vertical towers filled with plastic packing or other media.

The availability of inexpensive plastic tower packings has led to their use as tricklingfilter beds in tall towers, some as high as 20 meters. As early as the 1960s, such towerswere in use at: the Great Northern Oil's Pine Bend Refinery in Minnesota; the CitiesService Oil Company Trafalgar Refinery in Oakville, Ontario and at a kraft paper mill.

The treated water effluent from industrial wastewater trickling filters is very oftensubsequently processed in a clarifier-settler to remove the sludge that sloughs off themicrobial slime layer attached to the trickling filter media (see Image 1 above).

Currently, some of the latest trickle filter technology involves aerated biofilters whichare essentially trickle filters consisting of plastic media in vessels using blowers to inject

air at the bottom of the vessels, with either downflow or upflow of the wastewater.

BOD & COD:
http://en.wikipedia.org/wiki/Pine_Bend_Refineryhttp://en.wikipedia.org/wiki/Minnesotahttp://en.wikipedia.org/wiki/Oakville,_Ontariohttp://en.wikipedia.org/wiki/Pine_Bend_Refineryhttp://en.wikipedia.org/wiki/Minnesotahttp://en.wikipedia.org/wiki/Oakville,_Ontario


11/24

Wastewater quality indicators

Wastewater quality indicators such as thebiochemical oxygen demand (BOD) andthe chemical oxygen demand (COD) are essentially laboratory tests to determinewhether or not a specificwastewaterwill have a significant adverse effect upon fish orupon aquatic plant life.

Wastewater biochemical oxygen demand and chemical oxygen demand

Anyoxidizable material present in a natural waterway or in an industrial wastewaterwill be oxidized both bybiochemical (bacterial) or chemical processes. The result is thatthe oxygen content of the water will be decreased. Basically, the reaction for biochemicaloxidation may be written as:

Oxidizable material + bacteria + nutrient + O2 CO2 + H2O + oxidizedinorganics such as NO3 or SO4

Oxygen consumption by reducing chemicals such as sulfides and nitrites is typified asfollows:

S-- + 2 O2 SO4--NO2- + O2 NO3-

Since all natural waterways contain bacteria and nutrient, almost any waste compoundsintroduced into such waterways will initiate biochemical reactions (such as shownabove). Those biochemical reactions create what is measured in the laboratory as theBiochemical Oxygen Demand (BOD).

Oxidizable chemicals (such as reducing chemicals) introduced into a natural water willsimilarly initiate chemical reactions (such as shown above). Those chemical reactionscreate what is measured in the laboratory as the Chemical Oxygen Demand (COD).

Biochemical Oxygen Demand or Biological Oxygen Demand (BOD) is achemical procedure for determining how fast biological organisms use up oxygen in abody of water. It is used in water qualitymanagement and assessment, ecology andenvironmental science. BOD is not an accurate quantitative test, although it could be

considered as an indication of the quality of a water source.

BOD can be used as a gauge of the effectiveness ofwastewater treatment plants. It islisted as a conventional pollutant in the U.S. Clean Water Act.

Typical BOD values

Most pristine rivers will have a 5-day BOD below 1 mg/L. Moderatelypolluted riversmay have a BOD value in the range of 2 to 8 mg/L. Municipal sewage that is efficiently

treated by a three-stage process would have a value of about 20 mg/L or less. Untreated
http://en.wikipedia.org/wiki/Biochemical_oxygen_demandhttp://en.wikipedia.org/wiki/Chemical_oxygen_demandhttp://en.wikipedia.org/wiki/Laboratoryhttp://en.wikipedia.org/wiki/Testhttp://en.wikipedia.org/wiki/Wastewaterhttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Aquatic_planthttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Inorganic_chemistryhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Water_qualityhttp://en.wikipedia.org/wiki/Ecologyhttp://en.wikipedia.org/wiki/Environmental_sciencehttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Conventional_pollutanthttp://en.wikipedia.org/wiki/Clean_Water_Acthttp://en.wikipedia.org/wiki/Pollutionhttp://en.wikipedia.org/wiki/Sewagehttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Biochemical_oxygen_demandhttp://en.wikipedia.org/wiki/Chemical_oxygen_demandhttp://en.wikipedia.org/wiki/Laboratoryhttp://en.wikipedia.org/wiki/Testhttp://en.wikipedia.org/wiki/Wastewaterhttp://en.wikipedia.org/wiki/Fishhttp://en.wikipedia.org/wiki/Aquatic_planthttp://en.wikipedia.org/wiki/Redoxhttp://en.wikipedia.org/wiki/Biochemistryhttp://en.wikipedia.org/wiki/Inorganic_chemistryhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Water_qualityhttp://en.wikipedia.org/wiki/Ecologyhttp://en.wikipedia.org/wiki/Environmental_sciencehttp://en.wikipedia.org/wiki/Sewage_treatmenthttp://en.wikipedia.org/wiki/Conventional_pollutanthttp://en.wikipedia.org/wiki/Clean_Water_Acthttp://en.wikipedia.org/wiki/Pollutionhttp://en.wikipedia.org/wiki/Sewagehttp://en.wikipedia.org/wiki/Sewage_treatment


12/24

sewage varies, but averages around 600 mg/L in Europe and as low as 200 mg/L in theU.S., or where there is severe groundwater or surface water infiltration. (The generallylower values in the U.S. derive from the much greater water use per capita than otherparts of the world.)

The BOD5 test

BOD measures the rate of oxygen uptake by micro-organisms in a sample of water at atemperature of 20C and over an elapsed period of five days in the dark.

There are two recognized methods for the measurement of BOD.

Dilution method

To ensure that all other conditions are equal, a very small amount of micro-organismseed is added to each sample being tested. This seed is typically generated by dilutingactivated sludge with de-ionized water. The BOD test is carried out by diluting thesample with oxygen saturated de-ionized water, inoculating it with a fixed aliquot of

seed, measuring the dissolved oxygen (DO) and then sealing the sample to preventfurther oxygen dissolving in. The sample is kept at 20 C in the dark to preventphotosynthesis (and thereby the addition of oxygen) for five days, and the dissolvedoxygen is measured again. The difference between the final DO and initial DO is theBOD. The apparent BOD for the control is subtracted from the control result to providethe corrected value.

The loss of dissolved oxygen in the sample, once corrections have been made for thedegree of dilution, is called the BOD5. For measurement of carbonaceous BOD(cBOD), a nitrification inhibitor is added after the dilution water has been added to thesample. The inhibitor hinders the oxidation of nitrogen.

BOD can be calculated by:

Undiluted: Initial DO - Final DO = BOD Diluted: ((Initial DO - Final DO)- BOD of Seed) x Dilution Factor

BOD is similar in function to chemical oxygen demand (COD), in that both measure theamount oforganic compounds in water. However, COD is less specific, since it measureseverything that can be chemically oxidised, rather than just levels of biologically activeorganic matter.

Manometric method

This method is limited to the measurement of the oxygen consumption due only tocarbonaceous oxidation.Ammonia oxidation is inhibited.

The sample is kept in a sealed container fitted with a pressure sensor. A substance thatabsorbs carbon dioxide (typicallylithium hydroxide) is added in the container above thesample level. The sample is stored in conditions identical to the dilution method.Oxygen is consumed and, as ammonia oxidation is inhibited, carbon dioxide is released.The total amount of gas, and thus the pressure, decreases because carbon dioxide isabsorbed. From the drop of pressure, the sensor electronics computes and displays the

consumed quantity of oxygen.
http://en.wikipedia.org/wiki/Europehttp://en.wikipedia.org/wiki/U.S.http://en.wikipedia.org/wiki/Groundwaterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Activated_sludgehttp://en.wikipedia.org/wiki/De-ionized_waterhttp://en.wikipedia.org/wiki/Dissolved_oxygenhttp://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Chemical_oxygen_demandhttp://en.wikipedia.org/wiki/Organic_compoundhttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Lithium_hydroxidehttp://en.wikipedia.org/wiki/Europehttp://en.wikipedia.org/wiki/U.S.http://en.wikipedia.org/wiki/Groundwaterhttp://en.wikipedia.org/wiki/Surface_waterhttp://en.wikipedia.org/wiki/Activated_sludgehttp://en.wikipedia.org/wiki/De-ionized_waterhttp://en.wikipedia.org/wiki/Dissolved_oxygenhttp://en.wikipedia.org/wiki/Photosynthesishttp://en.wikipedia.org/wiki/Oxidationhttp://en.wikipedia.org/wiki/Chemical_oxygen_demandhttp://en.wikipedia.org/wiki/Organic_compoundhttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Lithium_hydroxide


13/24

The main advantages of this method compared to the dilution method are:

simplicity: no dilution of sample required, no seeding, no blank sample direct reading of BOD value continuous display of BOD value at the current incubation time.

Furthermore, as the BOD measurement can be monitored continuously, a graph of itsevolution can be plotted. Interpolation of several graphs on a similar water may build anexperience of its usual evolution, and allow an estimation of the five days BOD after asearly as the first two days of incubation.[1]

History of the use of BOD

The Royal Commission on River Pollution, which was established in 1865 and theformation of the Royal Commission on Sewage Disposal in 1898 led to the selection in1908 of BOD5 as the definitive test for organic pollution of rivers. Five days was chosenas an appropriate test period because this is supposedly the longest time that river watertakes to travel from source to estuary in the U.K. In 1912, the commission also set a

standard of 20 ppm BOD5 as the maximum concentration permitted in sewage worksdischarging to rivers, provided that there was at least an 8:1 dilution available at dryweather flow. This was contained in the famous 20:30 (BOD:Suspended Solids) + fullnitrification standard which was used as a yardstick in the U.K. up to the 1970s forsewage works effluent quality.

Both the BOD and COD tests are a measure of the relative oxygen-depletion effect of awaste contaminant. Both have been widely adopted as a measure of pollution effect. TheBOD test measures the oxygen demand ofbiodegradable pollutants whereas the CODtest measures the oxygen demand of biogradable pollutants plus the oxygen demand ofnon-biodegradable oxidizable pollutants.

The so-called 5-day BOD measures the amount of oxygen consumed by biochemicaloxidation of waste contaminants in a 5-day period. The total amount of oxygenconsumed when the biochemical reaction is allowed to proceed to completion is calledthe Ultimate BOD. The Ultimate BOD is too time consuming, so the 5-day BOD hasalmost universally been adopted as a measure of relative pollution effect.

There are also many different COD tests. Perhaps, the most common is the 4-hour COD.

It should be emphasized that there is no generalized correlation between the 5-day BODand the Ultimate BOD. Likewise, there is no generalized correlation between BOD and

COD. It is possible to develop such correlations for a specific waste contaminant in aspecific wastewater stream, but such correlations cannot be generalized for use with anyother waste contaminants or wastewater streams.
http://en.wikipedia.org/wiki/Biochemical_oxygen_demand#cite_note-0http://en.wikipedia.org/w/index.php?title=Royal_Commission_on_River_Pollution&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Royal_Commission_on_Sewage_Disposal&action=edit&redlink=1http://en.wikipedia.org/wiki/Water_pollutionhttp://en.wikipedia.org/wiki/Estuaryhttp://en.wikipedia.org/wiki/U.K.http://en.wikipedia.org/wiki/Nitrificationhttp://en.wikipedia.org/wiki/Effluenthttp://en.wikipedia.org/wiki/Biodegradationhttp://en.wikipedia.org/wiki/Biochemical_oxygen_demand#cite_note-0http://en.wikipedia.org/w/index.php?title=Royal_Commission_on_River_Pollution&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Royal_Commission_on_Sewage_Disposal&action=edit&redlink=1http://en.wikipedia.org/wiki/Water_pollutionhttp://en.wikipedia.org/wiki/Estuaryhttp://en.wikipedia.org/wiki/U.K.http://en.wikipedia.org/wiki/Nitrificationhttp://en.wikipedia.org/wiki/Effluenthttp://en.wikipedia.org/wiki/Biodegradation


14/24

Merits of Trickling Filter: -

Economic ConsiderationsWhile direct economic comparison to other treatment processes canonly be made on a case-by-case basis, some general comparisons can bemade.

The containment vessel for bio-towers does not need to be constructed

to hold the weight of the wastewater, as do activated sludge tanks.Vessels are often built of low-cost, pre-cast concrete panels or boltedsteel plates.

Power consumption for bio-towers is limited to pumping wastewaterand re-circulated wastewater. No aeration power is needed (with theexception, in certain cases, of ventilation fans.)

Maintenance for bio-towers is limited to the distributor arm andpumps. Blowers, air diffusers, return sludge pumps, and associatedelectrical equipment and controls are not needed.

Less operator labor is needed to monitor, sample, and makeadjustments to the process for the simpler trickling filter.

Odor containment, if desired, is accomplished with the simpleaddition of a dome cover to the bio-tower tank.

Demerits of Trickling Filter: -

Trickling filters are packed with rocks, on the surface of which bacteria are allowed to

grow, while wastewater is trickled over through nozzles, allowing for consumption ofdissolved organics by bacteria. The relative effectiveness in BOD removal of tricklingfilters is relatively low compared to other secondary treatment systems.

In tests in Switzerland, the trickling filter could treat waste water containing

ammonium, nitrate, phenol and other hazardous contaminants such as PAH. As no

experiments could be done in India, long-term performance remains unknown

In India, the trickling filter technology is not recognized as an applicable solution to

gasifier waste water problems yet.


15/24

Some facts to be known about water condition in W.B:Water For People was awarded a prestigious Grainger Award by the U.S. National

Academy of Engineering (NAE) in February during a Washington, DC, gala for its

innovative work in arsenic removal from potable water in the West Bengal region of

India, where millions of people are at risk from naturally occurring arsenic prevalent in

groundwater supplies. Members of the development team included Prof. Arup K.

SenGupta, Ph.D., John E. Greenleaf, Lee M. Blaney, Owen E. Boyd, and Arun K. Deb.

Dr. SenGupta and Lehigh University partnered in the submission of the awardapplication. He and his research assistants built a model of the filters used in West

Bengal, India, so that NAE could test the filter under laboratory conditions. Theyworked with Bengal Engineering & Science University in India to develop the technologyused by Water For People in West Bengal, India.

In the system, water is hand-pumped into a fixed-bed column, where it passes throughactivated alumina or hybrid anion exchanger (HAIX) to remove arsenic. After passingthrough a chamber of graded gravel to remove particulates, its ready to drink. Each unitserves about 300 households. The system is used in over 160 locations in West Bengal,India, providing arsenic-safe potable water to nearly 170,000 villagers.

Technologies Available for Arsenic treatment that might besuitable for West Bengal:

The technologies under review perform most effectively when treating arsenic in the

form of As(V). As (III) may be converted through pre-oxidation to As(V). Data on

oxidants indicate that chlorine, ferric chloride, and potassium permanganate are

effective in oxidizing As(III) to As(V). Pre-oxidation with chlorine may create

undesirable concentrations of disinfection by-products. Ozone and hydrogen peroxide

should oxidize As(III) to As(V), but no data are available on performance.

Coagulation/Filtration (C/F), is an effective treatment process for removal of As(V)according to laboratory and pilot-plant tests. The type of coagulant and dosage usedaffects the efficiency of the process. Within either high or low pH ranges, the efficiencyof C/F is significantly reduced. Alum performance is slightly lower than ferric sulfate.Other coagulants were also less effective than ferric sulfate. Disposal of the arsenic-contaminated coagulation sludge may be a concern especially if nearby landfills isunwilling to accept such a sludge.

Lime Softening (LS) operated within the optimum pH range of greater than 10.5 islikely to provide a high percentage of As removal for influent concentrations of 50 g/L.However, it may be difficult to reduce consistently to 1 g/L by LS alone. Systems using

LS may require secondary treatment to meet that goal.


16/24

Activated Alumina(AA) is effective in treating water with high total dissolved solids(TDS). However, selenium, fluoride, chloride, and sulfate, if present at high levels, maycompete for adsorption sites. AA is highly selective towards As(V); and this strongattraction results in regeneration problems, possibly resulting in 5 to 10 percent loss ofadsorptive capacity for each run. Application of point-of-use treatment devices wouldneed to consider regeneration and replacement.

Ion Exchange (IE) can effectively remove arsenic. However, sulfate, TDS, selenium,fluoride, and nitrate compete with arsenic and can affect run length. Passage through aseries of columns could improve removal and decrease regeneration frequency.Suspended solids and precipitated iron can cause clogging of the IE bed. Systemscontaining high levels of these constituents may require pretreatment.

Reverse Osmosis (RO) provided removal efficiencies of greater than 95 percent whenoperating pressure is at ideal psi. If RO is used by small systems in the western U. S.,60% water recovery will lead to an increased need for raw water. The water recovery isthe volume of water produced by the process divided by the influent stream (productwater/influent stream). Discharge of reject water or brine may also be a concern. If RO

is used by small systems in the western U. S., water recovery will likely need to beoptimized due to the scarcity of water resources. The increased water recovery can leadto increased costs for arsenic removal.

Electrodialysis Reversal (EDR) is expected to achieve removal efficiencies of 80percent. One study demonstrated arsenic removal to 3 g/L from an influentconcentration of 21 g/L.

Nanofiltration (NF) was capable of arsenic removals of over 90%. The recoveriesranged between 15 to 20%. A recent study showed that the removal efficiency droppedsignificantly during pilot-scale tests where the process was operated at more realistic

recoveries. If nanofiltration is used by small systems in the western U. S., water recoverywill likely need to be optimized due to the scarcity of water resources. The increasedwater recovery can lead to increased costs for arsenic removal.

Point of Use/Point of Entry (POU/POE)The 1996 SDWA amendments specificallyidentify Point-of-Use (POU) and Point-of-Entry (POE) devices as options that can beused for compliance with NPDWRs. POU and POE devices can be effective andaffordable compliance options for small systems in meeting a new arsenic MCL. AFederal Register notice is being prepared by EPA to delete the prohibition {141.101} onthe use of POU devices as compliance technologies. Because of this prohibition, few fieldstudies exist on the application of POU and POE devices. One such case study was

performed by EPA, in conjunction with the Village of San Ysidro, in New Mexico(Rogers 1990). The study was performed to determine if POU Reverse Osmosis (RO)units could satisfactorily function in lieu of central treatment to remove arsenic andfluoride from the drinking water supply of a small rural community of approximately200 people. A RO unit, a common type of POU device, is a membrane system thatrejects compounds based on their molecular properties and characteristics of the reverseosmosis membrane. The RO units removed 86% of the total arsenic.

Prospective Technologies

Ion Exchange with Brine Recycle. Research recently completed by the University of

Houston (Clifford) at McFarland, CA and Albuquerque, NM has shown that ion

exchange treatment can reduce arsenic (V) levels to below 2 g/L even with sulfate


17/24

levels as high as 200 mg/L. Sulfate does impact run length, however; the higher the

sulfate concentration, the shorter the run length to arsenic breakthrough. The research

also showed the brine regeneration solution could be reused as many as 20 times with

no impact on arsenic removal provided that some salt was added to the solution to

provide adequate chloride levels for regeneration. Brine recycle reduces the amount of

waste for disposal and the cost of operation.

Iron (Addition) Coagulation with Direct Filtration. The University of Houston(Clifford) recently completed pilot studies at Albuquerque, NM on iron addition(coagulation) followed by direct filtration (microfiltration system) resulting in arsenic(V) being consistently removed to below 2 g/L. Critical operating parameters are irondose, mixing energy, detention time, and pH.

Conventional Iron/Manganese (Fe/Mn) Removal Processes. Ironcoagulation/filtration and iron addition with direct filtration methods are effective forarsenic (V) removal. Source waters containing naturally occurring iron and/ormanganese and arsenic can be treated for arsenic removal by using conventional Fe/Mn

removal processes. These processes can significantly reduce the arsenic by removing theiron and manganese from the source water based upon the same mechanisms that occur with the iron addition methods. The addition of iron may be required if theconcentration of naturally occurring iron/manganese is not sufficient to achieved therequired arsenic removal level.

EPA Research Activities

EPA' s Office of Research and Development(ORD) is in the process of funding three

arsenic treatment research activities. First, a field study will be conducted to evaluate

the effectiveness of eight full scale drinking water treatment plants to remove arsenic

from their source water on a sustained basis for six to twelve months. The processesincluded in this field study will be two large system technologies, conventional

coagulation/ filtration, and lime softening, and two small system technologies, ion

exchange and the iron/manganese, oxidation/filtration process. These evaluation

studies will also include characterization and quantification of the residuals produced by

each process. A second project will consist of laboratory and pilot plant studies to

characterize the kinetics of oxidation of arsenic III to arsenic V by various oxidants and

oxidation processes. And finally, a workgroup meeting is being planned for February,

1998 to review the state of the science of existing and developing drinking water

treatment technologies effective for arsenic removal. Future work will entail additional

full scale field studies on other small system treatment alternatives, such as activatedalumina treatment, residuals characterization and management studies, and treatment

cost and evaluation studies.

Issues

Coagulation/Filtration and Lime Softening:

Not appropriate for most small systems--high cost, need for well trainedoperators, and variability in process performance

CF & LS alone may have difficultly consistently meeting a low-level MCL. IE maybe useful as a polishing step.

Disposal of sludge may be a problem


18/24

Activated Alumina:

Lack of availability of F-1 alumina. Testing of substitute not yielding sameresults.

Chemical handling requirements may make this process too complex and

dangerous for many small systems AA may not be efficient in the long term, as it seems to lose significant adsorptive

capacity with each regeneration cycle Highly concentrated waste streams-disposal of brine may be a problem

Ion Exchange:

Highly concentrated waste by-product stream- disposal of brine may be aproblem. Brine recycling might reduce the impact.

Sulfate levels affect run length

Recommended as a BAT primarily for small, ground water systems with lowsulfate and TDS and as the polishing step after filtration for low-level options

Reverse Osmosis/Nanofiltration:

Extensive corrosion control could be required for low-level option--ability toblend would be limited

Water rejection (about 20-25 percent of influent) may be an issue in water-scarceregions

Electrodialysis Reversal:

Water rejection (about 20-25 percent of influent) may be an issue in water-scarceregions

May not be competitive with respect to costs and process efficiency whencompared with RO and NF, although it is easier to operate

Point of Use/Point of Entry:

Adopting a POU/POE treatment system in a small community requires morerecordkeeping to monitor individual devices than does central treatment.

POU/POE systems require special regulations regarding customerresponsibilities, water utility responsibilities, and the requirement of installationof the devices in each home obtaining water from the utility.


19/24

Tirupur Water and Wastewater Treatment Project, India

Water treatment plant capacity

185 million litres/day

Plant type

Conventional rapid gravity filter with Lamella clarifier

Wastewater treatment plant capacity

15 million litres/day (expandable to 30mld)

Plant type

Secondary treatment level - activated sludge

Footprint

5.2 hectares

Estimated cost

$220 million

Tirupur Area Development Project announced

1991

In 2006, the recently completed Tirupur water system the first public-privatepartnership project in the history of Indias water sector gained a distinction in theindustrial category of the Global Water Awards, being highly commended by the judges.

The project involved the construction of two new treatment works, ultimately providingthe area with a daily supply of 185 million litres of potable water and the capacity totreat 30 million litres of domestic sewage.

In addition to the plants, the scheme also required the construction of an intake

structure downstream of the Bhavani-Cauvery river confluence, 55km of transmissionpipeline, a system of 25 reservoirs, a master balancing reservoir and a distribution andsewer network.

PROJECT FUNDING

Project funding was a mixture of debt and equity, an approach which involved a numberof sources including public money, various commercial interests, financial institutionsand international funding agencies. Assistance came from the Infrastructure Leasingand Financial Services (IL&FS) and from the US Agency for International Development(USAID) with loan guarantees over 30 years for $25 million (US). The project came in

on its $220 million budget.


20/24

BACKGROUND

Tirupur is located in Tamil Nadu state and is Indias largest producer of cotton knitwear.With over 2,500 textile businesses located within a 25-mile radius, earning some $1billion, the region one of the most economically dynamic in Southern India accountsfor over 75% of the entire countrys knitwear exports.

Water is essential to the industry and historically groundwater and tankers have beenextensively used to overcome the citys lack of supply. However, the industry has itselfheavily polluted the groundwater with chemical dyes; it has been said and not entirelyfrivolously that the colour of the regions water varies with the mood of Paris fashions.

With the groundwater having become progressively more saline and contaminated, by1990 the need to address the situation had become of pressing regional importance andsteps began which ultimately led to the instigation of the project.

While the need for an improved water system was clear, the challenge was to finance it.Ultimately, this required the formation of a Special Purpose Vehicle (SPV) to accesscommercial funding and implement the project. In 1995, the New Tirupur AreaDevelopment Corporation Limited (NTADCL) was formed for the role and subsequentlybegan the process of international competitive tendering.

Since the municipal area also lacked an organised system of drainage, sewage collectionor treatment, it was decided to address both this and the provision of potable water, aspart of the Tirupur Area Development Project. An associated wider scheme of works alsoencompasses additional local infrastructure requirements including roads,telecommunications and power.

THE PROJECT

The project itself was split into three separate contracts, two awarded on a engineer,procure and construct (EPC) basis and one to Operate and Manage (O&M) the finishedfacility.

Construction began in October 2002 and the main civil /mechanical work wascompleted by December 2004. Pipeline testing began in March 2005. The watertreatment plant commissioning followed the next month and the Tirupur Municipalitybegan receiving project water on alternate days in October 2005, after a two month trial

period. The wastewater treatment plant was originally scheduled for completion inOctober 2005, but was delayed until February 2006 by a heavy monsoon and floods.

Once fully operational, the system will service nearly 1,000 textile units and over 1.6million residents in Tirupur and its surrounding areas. A daily total of around 125million litres of water will be supplied to the knitwear dyeing and bleaching industry, 25million litres to the Tirupur municipality, which includes 60,000 slum dwellers and 35million litres will be shared between the regions remaining rural towns, villages andsettlements.


21/24

Sanitation provision within the scheme includes 88 of the citys designated slum areas.The water treatment plant was built to a conventional design, using a rapid gravity filterwith a lamella clarifier to provide the 185 million litres per day capacity.

The wastewater facility takes domestic sewage only and uses an activated sludge systemto achieve secondary treatment standards. The plant discharges into Noyyal river.Initially built with a capacity of 15 million litres per day, its design allows eventualexpansion to double that, when sewer provision is extended to the remaining 15 of thetowns 52 wards.

Although the construction elements of the project were implemented in two parts, theirexecution was effectively simultaneous. The EPC I work involved building the waterintake, the transmission pipeline from the river to Tirupur and the master balancingreservoir, while the EPC 2 contract, covered the main feeder pipelines and distributionnetworks, overhead and ground level storage tanks and the sewerage network in theTirupur town area.

Once the construction work was completed and the master balancing reservoir linked to

the distribution network, Mahindra Water Utilities' 30 year Operation and Maintenance(O&M) contract came into effect.


22/24

Members of Runners Group: -

Arunava Roy (Group Leader).

14

Sujata Kabiraj

91

Gaurav kumar Verma

31

Kunal kumar

45

Tuhinangshu Kar

98

Rajesh Bin64

Somnath Das

85

Khusboo Verma

41

Tamal Chakraborty

96

Anusha Gangwar

11


23/24

Haldhar Prasad

33

Dewanshu Kumar

30

Palash Paul

59

Swarup Roy

95

Kuldeep kumar Ram

44

Rohit Mahato

67

Niraj Kumar Singh 58

Bibliography:-

http://en.wikipedia.org/wiki/Trickling_filter

http://en.wikipedia.org/wiki/Biochemical_oxygen_demand

http://en.wikipedia.org/wiki/List_of_waste_water_treatment_t

echnologies

http://www.eng-consult.com/arsenic/treat1.htm

http://ww.pennnet.com/display_article/293300/20/ARTCL/non

e/none/1/W-... - 61k - 2007-04-01
http://en.wikipedia.org/wiki/Biochemical_oxygen_demandhttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologieshttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologieshttp://www.eng-consult.com/arsenic/treat1.htmhttp://ww.pennnet.com/display_article/293300/20/ARTCL/none/none/1/W-...%20-%2061k%20-%202007-04-01http://ww.pennnet.com/display_article/293300/20/ARTCL/none/none/1/W-...%20-%2061k%20-%202007-04-01http://en.wikipedia.org/wiki/Biochemical_oxygen_demandhttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologieshttp://en.wikipedia.org/wiki/List_of_waste_water_treatment_technologieshttp://www.eng-consult.com/arsenic/treat1.htmhttp://ww.pennnet.com/display_article/293300/20/ARTCL/none/none/1/W-...%20-%2061k%20-%202007-04-01http://ww.pennnet.com/display_article/293300/20/ARTCL/none/none/1/W-...%20-%2061k%20-%202007-04-01


24/24

Documents

Final Project Softcopy