Chemical Oxygen Demand (Sample 1) 500 450 400 350 300 L / g m 250 200
Water In
150
Water Out
100 50
Grade B
0 60 Minutes
55 Minutes 50 Minutes 45 Minutes
Duration
Figure 4.3 Graph of COD changes against duration of SBR operation
Figure shows the result of COD content in the wastewater at UiTM Puncak Alam wastewater treatment plant. This is a sample 1 result of water testing. There are two types of water has been tested which is the water in (water come into the plant or influent) and water out (water discharge from the plant or effluent). COD in a wastewater been tested for each duration of SBR operation at this plant. For the 60 minutes duration of SBR operation, COD content of effluent is 19 mg/L. It was increase up to 26 mg/L after reducing the SBR system operation time to 55 minutes. For 50 minutes operation, COD content shows the reading 30 mg/L. And after the 45 minutes operation which is the minimum operation time of the experiment, COD content increase to 32 mg/L. By referring Table 2.1(Standard Effluent of Malaysia), COD content for the minimum operation time is standard A effluent. Grade of effluent will reduce to standard B if COD content in effluent exceeds 100 mg/L. For the sample 2 and 3 of the experiment the result shows it close at similarities between the three results.
