Consumption, biological

DOC concentration to be relatively low, and oxygen content relatively high. During this period, phosphates are high, probably because of the combined leaching from the basin, mobilization from the sediment, and lower biological consumption at lower temperatures. 

There is also a slow filtration variant of filtration used by some water treatment plants, which combines both a physical separation of suspended solids plus some biological consumption or adsorption of undesirable dissolved substances in the water supply in a single-, two-, or three-stage unit [6]. 

Natural degradation processes that occur in days or weeks in surface waters may take decades in groundwater, where flow rates are slow and microbiological activity is low. This limits the potential for natural purification through flushing or biological consumption. Once contaminated, groundwater is difficult and expensive—in many cases impossible—to rehabilitate. 

Quantification of moderate biological consumption and initially low oxygen concentrations in the Arabian Sea are needed to maintain the low oxygen layer. 

---