where did the term olly olly oxen free come from
Olly olly oxen free Cassidy and Hall write that the phrase may be derived from all ye, all ye outs in free, all the outs in free, or possibly calling all the "outs" in free; in other words, all who are out may come in without penalty.[2] Various calls used for such purposes have gone by the collective name of "ollyoxalls" in some places.[3] Tukey and Rowell speculate that the phrase may be a corruption of a hypothetical and ungrammatical German phrase alle, alle, auch sind frei (all, all, are also free).[1]
Biochemical oxygen demand BOD can be used as a gauge of the effectiveness of wastewater treatment plants. It is listed as a conventional pollutant in the U.S. Clean Water Act.[2]