Application of SAS through Embedding-Flocculation Strategy on Fishpond Water

The fishpond water sample was collected from a fishpond in Temoh, Perak, Malaysia as shown in Figure 3.5. The wavelength of the water sample was at 300 nm which was scanned by UV-Vis spectrophotometer.

Figure 3.5: Fishpond Water in Temoh, Perak (4.259486, 101.189674)

3.12.1 Determination of Cell Separation Efficiency and Sedimentation Rate

The flocculation of water sample was carried out with and without the presence of silica. For flocculation without adding silica, a total of 15 mL water sample was added into a vial followed by adding 1 mL of chitosan prepared with desired concentration. The chitosan at 0.96 mg/mL prepared (in section 3.4.1) was diluted to desired concentration according to Table 3.4 in order to achieve respective chitosan concentration in cell medium after 1 mL flocculant was added into 15 mL cell medium. The sample was stirred at 150

87

rpm for 20 minutes for flocculation and left for 60 minutes for sedimentation.

For embedding-flocculation strategy, a total of 15 mL water sample was first added into a vial followed by adding 0.5 mL of 1 g/L silica and 0.5 mL chitosan with desired concentration according to Table 3.6 (concentration of chitosan in cell medium from 1 to 10 mg/L). The sample was stirred at 150 rpm for 20 minutes for flocculation and left for 60 minutes for sedimentation.

After 60 minutes of sedimentation, a total of 3.5 mL of sample, that is about 1 mm distance below the liquid surface, was collected and the ABS of the sample collected was measured by UV-Vis spectrophotometer at wavelength of 300 nm. The cell separation efficiency can be calculated by the Equation 3.2. The cell sedimentation rate was determined by method in section 3.9.

3.12.2 Water Quality

The fishpond water was treated by centrifugation and SAS through embedding-flocculation respectively. For centrifugation method, the fishpond water was transferred into centrifuge tubes, the tubes were then placed into the centrifuge machine and operated at 2500 rpm for 20 minutes. The water quality of the treated and untreated fishpond water samples in terms of ammoniacal nitrogen level, nitrate level, ortho-phosphate level, turbidity, BOD, COD and total suspended solid (TSS) were measured.

88

3.12.2.1 Determination of Ammoniacal Nitrogen Level

HACH Method 10205 was used. The content of ammoniacal nitrogen was measured by using Nitrogen, Ammonia ULR TNTplus Reagent Set purchased from HACH. The lid of the DosiCap™ Zip cap was removed and the cap of the test vial that contained Nitrogen, Ammonia ULR TNTplus Reagent was removed. A total of 5 mL sample was added into the test vial and the DosiCap™ Zip cap was turned over immediately and was tightened on the test vial. The test vial was shaken until the reagent in the cap was dissolved and was left for 15 minutes for reaction. Lastly, the test vial was inserted into the UV-Vis spectrophotometer to determine the ammoniacal nitrogen level.

3.12.2.2 Determination of Nitrate Level

HACH Method 10206 was used. The content of nitrate was measured by using Nitrate LR TNTplus Reagent Set purchased from HACH. A total of 1 mL sample was first added into the test vial that contained Nitrate LR TNTplus Reagent and followed by adding 0.2 mL TNTplus Solution A. The cap was tightened on the test vial and the test vial was inverted until completely mixed. Lastly, the test vial was inserted into the UV-Vis spectrophotometer to determine the nitrate level.

89

3.12.2.3 Determination of Ortho-Phosphate Level

HACH Method 8048 was used. The content of ortho-phosphate was measured by using Reactive Phosphorus TNT Reagent Set purchased from HACH. Program 535 P React. PV TNT was started in the UV-Vis spectrophotometer. Then, 5 mL of the sample was added into the Reactive Phosphorus Test ‘N Tube Vial. The cap was tightened on the test vial and the test vial was inverted to mix. The test vial was then inserted into the 16-mm cell holder in UV-Vis spectrophotometer to set zero. After that, the content of PhosVer 3 Phosphate Powder Pillow provided was added into the same test vial. The test vial was shaken for 20 seconds and left for 2 minutes for reaction.

Lastly, the vial was inserted back into the 16-mm cell holder in UV-Vis spectrophotometer to determine the ortho-phosphate level.

3.12.2.4 Determination of Turbidity

A total 15 mL of sample was added into the sample bottle provided.

Then, the sample bottle was inserted into the portable Turbidimeter and the turbidity was measured.

90 3.12.2.5 Determination of BOD

Measurement of BOD was done by using BODTrak II apparatus. BOD range from 0 to 70 mg/L was chosen and 355 mL of sample is added into BODTrak II bottle. The content of nutrient buffer pillow was then added into the same BODTrak II bottle. A BODTrak II stir bar was put into the BODTrak II bottle and a seal cup was put into the neck of the bottle. After that, two potassium hydroxide pellets was added into the seal cup. Then, the BODTrak II bottle was put into the BODTrak chassis and the applicable tube was connected. The incubator temperature was set to 20 ^oC. Lastly, the test range was set and the test was allowed to run for 7 days before the result was obtained.

3.12.2.6 Determination of COD

HACH Method 8000 was used. The COD level was measured by using COD TNTplus™ Reagent Set, LR purchased from HACH. The DRB200 reactor was on and the temperature was set to 150 ^oC. The test vial was inverted several times to mix. A total of 2 mL sample was added to the test vial. The cap was tightened on the test vial and the test vial was inverted to mix. The test vial was inserted in the preheated COD reactor and the lid was closed. The test vial was then kept in the reactor for 2 hours. After 2 hours, the reactor was off to decrease the temperature until 120 ^oC. The test vial was inverted gently several times while the test vial was still hot and was left until

91

the temperature of test vial decreased to room temperature. Lastly, the test vial was inserted into the UV-Vis spectrophotometer to determine the COD level.

3.12.2.7 Determination of TSS

APHA method 3120 (American Public Health Association, Standard Methods for examination of water and wastewater) was used. The samples were tested by KenEp Laboratories (M) Sdn. Bhd, Ipoh, Perak.