Sentence:  Since experience indicates that effluents from oxidation ponds do not create major problems at these BOD concentrations , the goal for the effluent quality of the accelerated treatment system was the same as from conventional <WSD>oxidation</WSD> ponds . 
Meaning of the word marked with <WSD> tags:  the process of oxidizing; the addition of oxygen to a compound with a loss of electrons; always occurs accompanied by reduction