A procedure for measuring orthophosphate which employed ascorbic acid as reductant at room temperature was found to be unaffected by the presence of pyrophosphate, polyphosphate and two organic phosphates. Under the conditions used for extraction of orthophosphate from biological sludges obtained from wastewater-treatment systems, perchloric acid did not cause hydrolysis of pyrophosphate, polyphosphate or the organic phosphates; however, neutralization of the perchloric acid prior to analysis was necessary. The measurement of orthophosphate in the solid phase of sludge directly by extraction was modified so as to take into account the orthophosphate in the liquid phase remaining with the deposited solid phase. Values for orthophosphate in sludges from laboratory-scale and full-scale wastewater-treatment systems were not appreciably different when determined directly by extraction of the solid phase of a sludge or indirectly by subtraction of liquid-phase orthophosphate from total orthophosphate in the sample. However, due to the fewer steps involved, the indirect procedure has an advantage over the direct procedure.
DETERMINATION OF ORTHOPHOSPHATE IN ACTIVATED SLUDGES FROM WASTE-WATER-TREATMENT SYSTEMS SHOWING ENHANCED BIOLOGICAL PHOSPHATE REMOVAL
BLONDA M;BRUNETTI A;RAMADORI R;
1994
Abstract
A procedure for measuring orthophosphate which employed ascorbic acid as reductant at room temperature was found to be unaffected by the presence of pyrophosphate, polyphosphate and two organic phosphates. Under the conditions used for extraction of orthophosphate from biological sludges obtained from wastewater-treatment systems, perchloric acid did not cause hydrolysis of pyrophosphate, polyphosphate or the organic phosphates; however, neutralization of the perchloric acid prior to analysis was necessary. The measurement of orthophosphate in the solid phase of sludge directly by extraction was modified so as to take into account the orthophosphate in the liquid phase remaining with the deposited solid phase. Values for orthophosphate in sludges from laboratory-scale and full-scale wastewater-treatment systems were not appreciably different when determined directly by extraction of the solid phase of a sludge or indirectly by subtraction of liquid-phase orthophosphate from total orthophosphate in the sample. However, due to the fewer steps involved, the indirect procedure has an advantage over the direct procedure.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
