This metric is looking for the amount of organic material in tonnes (may be labelled as "Biological Oxygen Demand" or "Biochemical Oxygen Demand") contained in the company's water discharge. 

Search the report for the GRI Standard code 306-1 or do a keyword search of 'BOD' or 'oxygen demand' or 'water discharge'. If found, add the BOD value in tonnes and include a comment documenting exactly where within the source you found the information (page number) and include details of simple or complex calculations or conversions made to determine the metric value.

If the BOD value is reported in kilograms per tonne of product produced (kg/t.p.), you will need to convert this value into tonnes. To do so, find the tonnes of product produced in the report (if possible) and multiply the kg/t.p. by this value. Then convert the answer from kilograms into tonnes. Make sure you explain your working in the comments section. 

If you cannot find the BOD value in the company's report or cannot convert the value as reported, check the 'Unknown' box, and add any relevant comments before hitting submit. 

Companies may use an earlier G4-EN22 code to report this indicator.