According to the national standard (HJ 505-2009) Water quality-Determination of biochemical oxygen demand after five days(BOD5) for dilution and seeding method, 12 samples once, safe and reliable mercury-free differential pressure sensing method (breathing method) is brukes til å måle BOD i vann, som fullstendig simulerer den biologiske nedbrytningsprosessen av organisk materiale i naturen.