So far the common methods used to increase DOC in fermentation medium are aeration and agitation.
增大通气量和增加搅拌功率能改善溶氧，但会增加发酵生产的能耗成本。
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Activated sludge systems: this is the most common form of treatment, where micro-organisms are added to the wastewater and organic decomposition is encouraged through aeration and agitation.