الفلاتر الكربونية المحببة والبيليت المضغوطة

activated carbon filter

Depending on the type of water, suspended solids concentration, oil and grease, COD, BOD and pesticides contents, activated carbon filters are sized differently, but the basic

design data to clarify natural waters is the following:

Filtration velocity 2-8 m3/h.m2

Contact time 10 -30 minutes

Diameter 50 cm to 3m

Filtration area 0,2 to 7 m2

Flowrates 10L/h 100 m3/h

Pressure ratings 4 to10 bar

Vessel Materials Epoxy-coated steel

Polyester composite

Stainless steel (on request)

Bed depth 1 meter min.

Filtration media

GAC

Pesticide removal

COD removal

Dechlorination

Top manhole 2 1/2 to 6" DN 400

Accessories

5-ball or butterfly valves 5-butterfly valves

Options

Manometers, degaser, flowmeter
Control Automatic or manual backwash, on timer and.or differential pressure
More on activated carbon

For pesticide removal only at averal occurence at ppb levels, lifetime of an activated carbon bed can be up to 10 years. For natural organic matter or oil and grease, bed renewal can vary from few weeks to few years.

Adsorption / Active Carbon

Activated carbon adsorption

Adsorption is a process where a solid is used for removing a soluble substance from the water.

In this process active carbon is the solid. Activated carbon is produced specifically so as to achieve a very big internal surface (between 500 - 1500 m2/g).

This big internal surface makes active carbon ideal for adsorption. Active carbon comes in two variations: Powder Activated Carbon (PAC) and Granular Activated Carbon (GAC).

The GAC version is mostly used in water treatment, it can adsorb the following soluble substances:n

• Adsorption of organic, non-polar substances such as:

o Mineral oil

o BTEX

o Poly aromatic hydrocarbons (PACs)

o (Chloride) phenol

• Adsorption of halogenated substance: I, Br, Cl, H en F

• Odor

• Taste

• Yeasts

• Various fermentation products

• Non-polar substances (Substances which are non soluble in water)

Examples from active carbon in different processes:

• Ground water purification

• The de-chlorination of process water

• Water purification for swimming pools

• The polishing of treated effluent

Process description:

Water is pumped in a column which contains active carbon, this water leaves the column through a draining system.

The activity of an active carbon column depends on the temperature and the nature of the substances.

Water goes through the column constantly, which gives an accumulation of substances in the filter.

For that reason the filter needs to be replace periodically.

A used filter can be regenerated in different ways, granular carbon can be regenerated easily by oxidizing the organic matter.

The efficiency of the active carbon decreases by 5 - 10% 1). A small part of the active carbon is destroyed during the regeneration process and must be replaced.

If you work with different columns in series, you can assure that you will not have a total exhaustion of your purification system.

Description of adsorption:

Molecules from gas or liquid phase will be attached in a physical way to a surface, in this case the surface is from the active carbon.

The adsorption process takes place in three steps:

• Macro transport: The movement of organic material through the macro-pore system of the active carbon (macro-pore >50nm)

• Micro transport: The movement of organic material through the meso-pore and micro-pore system of the active carbon (micro-pore <2nm; meso-pore 2-50nm)

• Sorption: The physical attachment of organic material on the surface of active carbon in the meso-pores and micro-pores of the active carbon

The activity level of adsorption is based on the concentration of substance in the water, the temperature and the polarity of the substance.

A polar substance (= a substance which is good soluble in water) cannot or is badly removed by active carbon, a non-polar substance can be removed totally by active carbon.

Every kind of carbon has its own adsorption isotherm (see figure 1) and in the water treatment business this isotherm is definite by the function of Freundlich.

The function of Freundlich:

x/m = adsorbed substance per gram active carbon

Ce = concentration difference (between before and after)

Kf, n = specific constants

Normally we place a UV-disinfections unit after the active carbon column.

What is the difference between adsorption and absorption??

When a substance is attached to a surface is is called adsorption, is this case the substance is attached to the internal surface of active carbon.

When a substance is absorbed in a different medium it is called absorption. When a gas is taken in a solution it is called absorption.

Factors that influence the performance of active carbon in water:

• The type of compound to be removed.

Compounds with high molecular weight and low solubility are better absorbed.

• The concentration of the compound to be removed.

The higher the concentration, the higher the carbon consumption.

• Presence of other organic compounds which will compete for the available adsorption sites.

• The pH of the waste stream. For example, acidic compounds are better removed at lower pH.

According to this we can classify some chemicals by their probability of being efficiently adsorbed by active carbon in water:

1.- Chemicals with very high probability of being adsorbed by active carbon:

2,4-D Deisopropyltatrazine Linuron

Alachlor Desethylatrazine Malathion

Aldrin Demeton-O MCPA

Anthracene Di-n-butylphthalate Mecoprop

Atrazine

1,2-Dichlorobenzene Metazachlor

Azinphos-ethyl 1,3-Dichlorobenzene 2-Methyl benzenamine

Bentazone 1,4-Dichlorobenzene Methyl naphthalene

Biphenil 2,4-Dichlorocresol 2-Methylbutane

2,2-Bipyridine 2,5-Dichlorophenol Monuron

Bis(2-Ethylhexyl)Phthalate 3,6-Dichlorophenol Napthalene

Bromacil 2,4-Dichlorophenoxy Nitrobenzene

Bromodichloromethane Dieldrin m-Nitrophenol

p-Bromophenol Diethylphthalate o-Nitrophenol

Butylbenzene 2,4-Dinitrocresol p-Nitrophenol

Calcium Hypochloryte 2,4-Dinitrotoluene Ozone

Carbofuran 2,6-Dinitrotoluene Parathion

Chlorine Diuron Pentachlorophenol

Chlorine dioxide Endosulfan Propazine

Chlorobenzene Endrin Simazine

4-Chloro-2-nitrotoluene Ethylbenzene Terbutryn

2-Chlorophenol Hezachlorobenzene Tetrachloroethylene

Chlorotoluene Hezachlorobutadiene Triclopyr

Chrysene Hexane 1,3,5-Trimethylbenzene

m-Cresol Isodrin m-Xylene

Cyanazine Isooctane o-Xylene

Cyclohexane Isoproturon p-Xylene

DDT Lindane 2,4-Xylenol

2.- Chemicals with high probability of being adsorbed by active carbon:

Aniline Dibromo-3-chloropropane 1-Pentanol

Benzene Dibromochloromethane Phenol

Benzyl alcohol 1,1-Dichloroethylene Phenylalanine

Benzoic acid cis-1,2- Dichloroethylene o-Phthalic acid

Bis(2-chloroethyl) ether trans-1,2- Dichloroethylene Styrene

Bromodichloromethane 1,2-Dichloropropane 1,1,2,2-Tetrachloroethane

Bromoform Ethylene Toluene

Carbon tetrachloride Hydroquinone 1,1,1-Trichloroethane

1-Chloropropane Methyl Isobutyl Ketone Trichloroethylene

Chlorotoluron 4-Methylbenzenamine Vinyl acetate

3.- Chemicals with moderate probability of being adsorbed by active carbon*:

Acetic acid Dimethoate Methionine

Acrylamide Ethyl acetate Methyl-tert-butyl ether

Chloroethane Ethyl ether Methyl ethyl ketone

Chloroform Freon 11 Pyridine

1,1-Dichloroethane Freon 113 1,1,2-Trichloroethane

1,2-Dichloroethane Freon 12 Vinyl chloride

1,3-Dichloropropene Glyphosate

Dikegulac Imazypur
*(For this chemicals active carbon is only effective in certain cases).

4.- Chemicals for which adsorption with active carbon is unlikely to be effective.

However it may be viable in certain cases such as for low flow or concentrations:
Acetone
Methylene chloride

Acetonitrile 1-Propanol

Acrylonitrile
Propionitrile

Dimethylformaldehyde Propylene

1,4-Dioxane
Tetrahydrofuran

Isopropyl alcohol Urea

Methyl chloride

Factors that influence the performance of active carbon in air:

• Type of compound to be removed: In general compounds with a high molecular weight, lower vapor pressure/higher boiling point and high refractive index are better adsorbed.

• Concentration: The higher the concentration, the higher the carbon consumption.

• Temperature: The lower the temperature, the better the adsorption capacity.

• Pressure: The higher the pressure, the better the adsorption capacity.

• Humidity: The lower the humidity, the better the adsorption capacity.

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الفلاتر الكربونية المحببة والبيليت المضغوطة D51a5810

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Water treatment and air purification

Datasheet granular activated carbon

Description:

Steam activated, coal based, granular activated carbon. FA100 is recommended for dechlorination and purification of potable and process water.

TECHNICAL CHARACTERISTICS

Granulometry, U.S. Mesh
8 x 30 Mesh
>8 (2.36 mm)
<30 (0.6 mm)
ASTM D 2862

5% max
4% max
Apparent density, g/l
500 ± 30
ASTM D 2854

Moisture as packed, %
< 2
ASTM D 2867

Hardness, %
> 90
ASTM D 3802

Abrasion number, %
> 80
AWWA B 604/74

Iodine number, %
> 850
AWWA B 604/74

Methylene blue number, %
> 20
Spectrophotometric
Chlorine half length, cm
2,9
DIN 19603

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