yst ▁for , ▁but ▁not ▁the ▁primary ▁cause ▁of ▁the ▁mass ▁ext inction . ▁ ▁Use ▁by ▁humans ▁In ▁ 1 9 8 5 , ▁Sh im iz u ▁Const ruction ▁developed ▁a ▁bi ore actor ▁that ▁uses ▁M eth anos arc ina ▁to ▁treat ▁waste ▁water ▁from ▁food ▁processing ▁plants ▁and ▁paper ▁mill s . ▁ ▁The ▁water ▁is ▁fed ▁into ▁the ▁re actor ▁where ▁the ▁micro bes ▁break ▁down ▁the ▁waste ▁partic ulate . ▁ ▁The ▁m eth ane ▁produced ▁by ▁the ▁b acter ia ▁is ▁then ▁used ▁to ▁power ▁the ▁re actor , ▁making ▁it ▁cheap ▁to ▁run . ▁ ▁In ▁tests , ▁M eth anos arc ina ▁reduced ▁the ▁waste ▁concentration ▁from ▁ 5 , 0 0 0 – 1 0 , 0 0 0 ▁parts ▁per ▁million ▁( pp m ) ▁to ▁ 8 0 – 1 0 0 ▁p pm . ▁ ▁Further ▁treatment ▁was ▁necessary ▁to ▁finish ▁the ▁cle ans ing ▁process . ▁ ▁According ▁to ▁a ▁ 1 9 9 4 ▁report ▁in ▁Chem istry ▁and ▁Indust ry , ▁bi ore act ors ▁util izing ▁an a er ob ic ▁dig estion ▁by ▁M eth an oth rix ▁so eh ng en ii ▁or ▁M eth anos arc ina ▁produced ▁less ▁sl ud ge ▁by product ▁than ▁aer ob ic ▁counter parts . ▁ ▁M eth anos arc ina ▁react ors ▁operate ▁at ▁temper atures ▁r anging ▁from ▁ 3 5 ▁to ▁ 5 5   ° C ▁and ▁p H ▁ranges ▁of ▁ 6