What Does chemical oxygen demand Mean?
What Does chemical oxygen demand Mean?
Blog Article
From the existence of sulfuric acid, silver sulphate, and mercury sulphate, potassium dichromate oxidises the organic matter contained while in the h2o sample to make carbon dioxide (CO2) and h2o (H2O). The quantity of potassium dichromate utilised is set by evaluating the volumes of ferrous ammonium sulphate consumed all through blank and sample titrations.
The traditional procedures to determine COD and BOD are still commonly employed since they permit reliable outcomes to generally be acquired. Despite the usage of very harmful reagents, COD is utilized because the reactions make sure the overall oxidation on the raw materials, not like proposals where the alter in oxidizing brokers isn't going to allow such a response.
COD contrasts with biochemical oxygen demand (BOD), which depends on the usage of microorganisms to stop working the organic materials during the sample by aerobic respiration around an incubation period of time (commonly five days).
Wastewater created by commercial, industrial and institutional services is typically referred to as "superior-power" compared to regular residence wastewater.
TOC Examination includes the measurement in the carbon content right, generally employing significant-temperature combustion or moist chemical click here oxidation techniques.
Chemical oxygen demand is really an index of air pollution that steps the effect of pollutants on dissolved oxygen.
When obtaining benefits, the analyst might make use of a CHEMetrics photometer, or every other brands’ spectrophotometer. Just before transferring on, wipe down the reagent blank and test vials until finally They can be cleanse and dry.
Historically, potassium permanganate stuffed this function, but it was uncovered being inconsistent in its capability to oxidize every one of the natural make any difference in lots of squander samples.
The flask (made up of the extracted O&G) is reweighed. The first body weight in the flask is subtracted and the total O&G body weight in mg is calculated. The outcomes deliver the O&G concentration in mg/L.
The measurement of COD get more info is frequently performed by including a powerful oxidising agent, which include potassium dichromate, to your sample below acidic disorders and heated for 2 hrs. The amount of dichromate left offers an indication of the amount of natural subject was existing.
Doing this test the proper way is vital in identifying wastewater treatment method usefulness and may also help diagnose any difficulties in procedure.
Divide the COD concentration by the BOD concentration for every sample and typical the effects. By way of example, down below may be the COD:BOD ratio produced employing 3 wastewater samples from a foodstuff processor:
Consequently, these reagents are perfect for regime Examination in which no or extremely small chloride concentrations are predicted.
Approaches specializing in the detection procedure haven't still been thoroughly produced, as their only function is to make the ultimate response far more sensitive.