Can BOD values be negative?

Can BOD values be negative?

Both, Hydrogen peroxide and chlorine are toxic for Bacteria. And, therefore you got negative results in BOD test. Try to remove/neutralize these chemicals before experiment and seed with fresh microorganisms.

What does Chemical Oxygen Demand measure?

Chemical Oxygen Demand (COD) is a test that measures the amount of oxygen required to chemically oxidize the organic material and inorganic nutrients, such as Ammonia or Nitrate, present in water.

Is oxygen a chemical demand?

In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution. The most common application of COD is in quantifying the amount of oxidizable pollutants found in surface water (e.g. lakes and rivers) or wastewater.

What is chemical oxygen demand in wastewater?

Chemical oxygen demand (COD) is the amount of dissolved oxygen that must be present in water to oxidize chemical organic materials, like petroleum. COD is used to gauge the short-term impact wastewater effluents will have on the oxygen levels of receiving waters.

What if chemical oxygen demand is high?

Higher COD levels mean a greater amount of oxidizable organic material in the sample, which will reduce dissolved oxygen (DO) levels. A reduction in DO can lead to anaerobic conditions, which is deleterious to higher aquatic life forms.

What does chemical oxygen demand indicates Mcq?

Explanation: (i) The COD (Chemical oxygen demand) test is used to measure the content of organic matter of waste water, both biodegradable and non-biodegradble.

Why do we use chemical oxygen demand?

Chemical Oxygen Demand is an important water quality parameter because, similar to BOD, it provides an index to assess the effect discharged wastewater will have on the receiving environment. The COD test is often used as an alternate to BOD due to shorter length of testing time.

What is chemical oxygen demand simple terms?

Chemical oxygen demand is the amount of oxygen needed to oxidize the organic matter present in water. Chemical oxygen demand testing is used to determine the amount of oxidation that will occur and the amount of organic matter in a water sample.

How does chemical oxygen demand affect water quality?

Is chemical oxygen demand good?

The Significance of Chemical Oxygen Demand High chemical oxygen demand in water indicates greater levels of oxidizable organic matter and consequently, a lower amount of Dissolved Oxygen (DO). Critical DO depletion due to organic contamination can kill off aquatic life forms.

Can a chemical demand value be in negative?

Thi Lagan correctly pointed out that CHemical Oxygen Demand value can not be in negative. It is better to recheck your analysis precisely. Minus values could result of the only presence of oxygen in the best way or lack of accuracy in blank preparation in the wrong way.

What does chemical oxygen demand ( COD ) mean?

Chemical Oxygen Demand (COD) What Does Chemical Oxygen Demand (COD) Mean? Chemical oxygen demand is the amount of oxygen needed to oxidize the organic matter present in water. Chemical oxygen demand testing is used to determine the amount of oxidation that will occur and the amount of organic matter in a water sample.

When do you use chemical oxygen demand testing?

Chemical oxygen demand testing is used to determine the amount of oxidation that will occur and the amount of organic matter in a water sample. Chemical oxygen demand testing is also used to determine the amount of inorganic chemicals in a sample. Corrosionpedia explains Chemical Oxygen Demand (COD)

How is oxygen demand measured in a blank sample?

A blank sample is usually created by adding all reagents to a volume of distilled water. COD is measured for both the polluted water and blank samples, and the oxygen demand in the blank sample is subtracted from the COD for the original sample to ensure a true measurement of organic matter.