Introduction
Aeration techniques are wastewater treatment methods in which air or oxygen is brought into contact with water to increase the dissolved oxygen content. The supplied oxygen helps in the oxidation of organic pollutants, thereby reducing the Chemical Oxygen Demand (COD) of wastewater. Aeration also improves mixing, removes unpleasant gases and odors, and enhances biological activity. Common aeration techniques include bubble aeration and sprinkler aeration, which differ in their method of oxygen transfer and treatment efficiency.
Aim
- To determine initial and final COD values.
- To perform COD reduction using natural and aeration methods.
- To compare treatment efficiencies.
- To identify the most effective method for wastewater treatment.
Methods to be studied
- Aeration using Azolla (Photosynthesis).
- Sedimentation using polyelectrolytes and alum.
- Aeration due to Bubbling.
- Aeration due to sprinkler mechanism.
Before applying methods, Take initial reading of COD for different types of sample and select one sample for applying aeration methods. You can read Anushka Ghodake’s blog regrading COD and DO for reference. We have selected the sample of well near nageshwar temple in pabal whose initial COD is 300 mg/L. Now let us see the materials required and procedure for each of the above method.
Aeration using Azolla (Photosynthesis)
Basic Knowledge – Azolla reduces COD by releasing oxygen during photosynthesis, which helps aerobic microorganisms decompose organic pollutants in wastewater. It also absorbs nutrients and supports microbial activity, thereby lowering the organic load and COD level.
Materials Required – Tray, Water sample (10L), Azolla
Procedure –
- Place a tray in such a place where it recieves daylight.
- Pour 10L of water sample in tray.
- Weigh about 140 grams of Azolla. (You can take azolla about 100-200 grams)
- Place the azolla on surface of the tray as it performs photosynthesis when it floats.
