Modified Winkler Method for Dissolved Oxygen Determination

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Modified Winkler method for dissolved oxygen determination


In this study the group has determined the presence of oxygen in sample through a modified winkler method. The amount of oxygen is determined through a series of reaction. A body of water can sustain life if dissolved oxygen is sufficed. Depletions in dissolved oxygen can cause major shifts in the kinds of aquatic organisms found in water bodies.

The amount of dissolved oxygen present in water or wastewater is essential for most forms of life. Dissolved oxygen is a good indicator of water quality. Oxygen dissolves into water by means of the atmosphere and plants. The primary source of oxygen for a body of water is from microscopic algae or submerged plants. In the presence of sunlight, these plants produce oxygen via photosynthesis.

Aerobic bacteria and Aquatic life such as fish must have dissolved oxygen to survive. According to Hitchman , Aerobic waste water treatment processes use aerobic and facultative bacteria to break down the organic compounds found in wastewater into more stable products that will not harm the receiving waters. Wastewater treatment facilities such as lagoons or ponds, trickling filters and activated sludge plants depend on these aerobic bacteria to treat sewage. If the amount of DO present in the wastewater process becomes too low, the aerobic bacteria that normally treat the sewage will die. The process will not operate efficiently and septic conditions will occur.

The DO test is used to monitor the process to guarantee that there is enough dissolved oxygen present to keep the process from becoming septic. Permanganate (Rideal- Stewart method) and other classical methods of analysis are the common means of determining the amount of dissolved oxygen. But they suffer from a number of drawbacks. They are rather slow in most of the steps, from sampling via addition of reagent to end point determination. They are often subject to interference...
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