{HEAD ~ The bioreactor} contains {TAIL ~ methanotrophic microorganisms} which convert the organic contaminants into mainly carbon dioxide 
contains
{ HEAD ~ The bioreactor } contains { TAIL ~ methanotrophic microorganisms } which convert the organic contaminants into mainly carbon dioxide
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH