What Does chemical oxygen demand Mean?
hyperlink November 13, 2018 H2o Quality Facts by Subject matter What is in that h2o that you just drank? Is it just hydrogen and oxygen atoms? Is it Protected for ingesting? All h2o is of a specific "high-quality" (and you may't convey to by just on the lookout), but what does "water excellent" definitely mean?During durations of very low DO, some