COMPARISON OF DAF KROFTA WITH METHODS OF WASTEWATER TREATMENT AND PAPER POWDER RECOVERY

 1. Comparison Table Of Daf Krofta And Dissolved Air Flotation In Wastewater Treatment – Paper Industry

CONTENT

DAF KROFTA

DAF

Application

Treatment of surplus water (wastewater) from paper machines

Treatment of surplus water (wastewater) from paper machines

Fluctuation of the TSS concentration of the effluent that the device can handle

Can handle TSS concentrations from 1000 – 7000 ppm (0.1 to 0.7%)

Can handle TSS concentration 5 2000 mg / L (0.2%)

The concentration of recovered powder

Reclaimed powder has a stable and consistent thickness during operation, DAF has the ability to adjust the concentration (thickness) of the dough by adjusting the water level in the level control basin to match suitable for production needs

The concentration of recovered powder cannot be adjusted. A concentration device is needed to maintain a stable concentration of the powder; or use a device called Consistency Regulator

Water quality after filtration

Treating up to 95% of TSS (suspended solids) in wastewater, increasing the efficiency of the microbiological treatment stage

A maximum of – 50-70% of TSS can be treated in wastewater with an input TSS concentration of 5 2000 mg /L

Flotation time of floc

Long, due to the height of DAF up to 3m, making the flotation process more effective and thorough

Low, there is not enough time to float all the floc, so it usually takes chemicals and TSS output is still high

Performance of dissolved oxygen

The gas achieves a high solubility ratio, with a micro balloon size (micro sized) sized). These micro bubbles will attach to suspended particles in wastewater and carry them to the surface

If domestic DAF, most cannot be designed quality air dispenser; After operating for a while, large bubbles will appear on the surface of the water, resulting in poor gas solubility, resulting in low flotation efficiency.

Chemical consumption

Low

1.5-2 times higher than DAF Krofta

Installation cost

Low installation costs

Very low installation cost

Investment cost

Medium

Low

2. Comparison Table Of Daf Krofta And Disc Filter Used In Powder Recovery And Wastewater Treatment – Paper Industry

CONTENT

DAF KROFTA

DISC FILTER

Application

Treatment of surplus water (wastewater) from paper machines

Treatment of surplus water (wastewater) from paper machines

Fluctuation of the TSS concentration of the effluent that the device can handle

Can handle TSS concentrations from 1000 – 7000 ppm (0.1 to 0.7%)

Can handle TSS concentrations from 2000 – 3000 ppm (0.2 – 0.3%)

Stability of quality after processing

Water quality after treatment fluctuates 2 – 4% (variable)

Water quality after treatment fluctuates 4 – 5% (variable)

The concentration of recovered powder

Reclaimed powder has a stable and consistent thickness during operation, DAF has the ability to adjust the concentration (thickness) of the powder by adjusting the water level in the level control basin to match suitable for production needs

The concentration of recovered powder cannot be adjusted. A concentration device is required to maintain the stability of the powder concentration, or use a Consistency Regulator

Procedure

Recover powder with Dissolved air floatation

Recover the powder using a screen with different hole sizes

Water quality after filtration

No turbid water, create only a stream of high clarity TSS <30-100 mg / I (depending on the concentration of inputs)

There are 3 quality of water after filtration:

• 70% cloudy water has TSS = 200-300 mg / L (usually returning to grinding)

• 20% clear water has TSS = 20-50 mg / L (return to blanket washing)

• 10% super clear water (return for washing water nozzles

Washing water

Not required

Cleaning water is required to clean the mesh with 300 Lpm flow

Handling area of the device

Small area requirements, specifically about 150-200 Lpm / m2

High filtration area requirements: 500 Lpm / m2

Installation

Installed on the common floor, from 2-4m high.

Powder recovered after DAF and clear water after DAF can be pumped or gravity flows to the production line’s storage basins.

Request high floor space +10 m.

It is required to build basins (minimum of 03 basins to hold 03 different types of water) and install more pumps

Power consumption

63HP for 300m3 of wastewater with a TSS concentration of 2000 mg / L (0.2%)

181 HP. 3 times higher than DAF

Chemical cost

DAF can be designed with or without chemicals. If using 2 DAF continuously, there will be no need to use chemicals to flotate the powder during operation

Do not use chemicals

Operating conditions

No filter cloth

Simple operation

It costs money to change filter cloth.

Maintenance, operation is more complicated and takes more resources

Installation cost

Low installation costs

High installation costs

Pneumatic pressure

6 to 7.5 kg/cm2

Not required 

Investment cost

Medium

Expensive – 2.5 – 3 times that of DAF

Comparison table of power consumption for 300m3 of water using DAF and disc filtration

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