Cathode Ray Tube Manufacturer, THAILAND

The plant has a waste stream that contains chromium (VI), chromium (III), fluoride, high COD, and very high level of dissolved solids. The dissolved solids content in the wastewater makes the treatment process difficult as it requires a great amount of treatment chemicals in order to remove the various contaminants. Lime was used in large amount to precipitate the metals and a lot of polymer was also used to enhance flocculation and settlement. Sodium metabisulfite was used to reduce chromium (VI) to Chromium (III) prior to treatment. Large volume of slimy sludge was generated and was difficult to dewater. The treatment demanded continuous adjustments of polymer dose to minimize solid carry over in the effluent and frequent cleaning of clogged filter cloths.

Several performance tests conducted with AQUASIL® AMX-5G proved that the AQUASIL® works well without the need for neutralization and flocculent. Analytical data in the TABLE below show the results for raw and treated water. The new treatment has eliminated the use of lime and flocculent. Although TDS in raw water does not exceed the discharge limit, the AQUASIL® was able to reduce the level by about 68%, thus improving the quality of the effluent. Hexavalent chrome was accomplished without a reduction step. The removal of Cr (VI) and fluoride in a single step using a single product is a testament to the high capacity of AQUASIL® for removal of the various contaminants.

Parameter

Discharge Limits (mg/L)

Before(mg/L)

After(mg/L)

BOD

60

12.4

< 5

COD

400

234.0

< 5

Total Dissolved Solids

5000

3923.0

1250.0

Total Suspended Solids

150

62.1

5.8

Chromium (VI)

0.25

24.90

ND

Chromium (III)

0.75

5.69

< 0.05

Aluminum

NA

11.10

< 0.50

Copper

2.0

0.17

< 0.02

Fluoride

5.0

16.50

2.35

Iron

NA

1.70

< 0.05

Lead

0.2

0.22

< 0.10

Nickel

1.0

0.43

< 0.02

Zinc

5.0

2.80

< 0.01

pH

5.5 – 9.0

5.9

8.9

The AQUASIL® treatment has simplified the wastewater treatment process. The process generates small volume of sludge that is easy to dewater. Generated waste is drier and passes the TCLP test. Furthermore, the AQUASIL® treatment reduces labor, energy, and maintenance costs.

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