a b
c
d
Figure 5.2 : Five sampling locations at IPD Pasir Mas , Kelantan
Faculty of Earth Science , UMK . The results show that the quality of stormwater has a consistent
BOD ,
AN and pH values at points 2 to 5 of the ecological swale ( Table 2 ). It is observed that the stormwater quality for this event belongs in the range of Class I to Class III based on the National River Water Quality Standards for Malaysia , also known as the Water Quality Index ( WQI ).
The WQI ( Table 2 ) at sampling point 5 , located downstream , shows that the recorded sub-index value was 87.35 ( Class II ) which is better in comparison to the value recorded at sampling point 1 , which was 77.69 ( Class II ). The performance of the ecological swale also varies in treating stormwater for the event on January 5 , 2021 . Table 3 shows that the values of BOD and COD are lower at point 4 and point 5 however , and the values of TSS and AN are slightly higher at point 4 when compared to the values recorded at point 1 .
e
Throughout the study , the range of stormwater runoff from the upstream to the downstream falls within the range of Class I to Class II ( Table 4 ). These results clearly show that BIOECODS is efficient in reducing pollutants in stormwater runoff . However , further data is needed to confirm BIOECODS performance in removing pollutants from stormwater runoff for various Annual Rain Intensity ( ARI ).
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