PHOSPHATE IN THE WATER: ORIGIN AND ELIMINATION.

Compouds of phosphorus are plant nutrients and lead to algae growth in surface waters. depending on the concentration of phosphate is in the water, can cause eutrophication. only 1gr of phosphate-phosphorus (PO4-P) causes tge growth of up to 100gr of algae. when these algae die, decomposition processes result in oxygen demand of about 150gr. the critical concentrations for eutrophication are emergingbetween 0.1-0.2mg/1PO4-Pin the water and between 0.005-0.01mg/PO4-P in cal water. given the potential threat to surface waters, the EU directive 91/271/EEC specifiest limit values for discharges of phosphate compounds to resrveing waters. depending on the size of the WWTP these values are 2mg/1total P (from 10.000 to 100.000 l) or 1mg1total P (>100.000 pe).

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