CARBONACEOUS, NITROGENOUS AND PHOSPHORUS MATTERS REMOVAL FROM DOMESTIC WASTEWATER BY AN ACTIVATED SLUDGE REACTOR OF NITRIFICATION-DENITRIFICATION TYPE

This paper proposes an environmental engineering method based onbiotechnology approach as one of the expected solutions that should beconsidered to implementing the activated sludge for improving the quality ofwater and living environment, especially to remove the major pollutant elementsof domestic wastewater. Elimination of 3 major pollutant elements, i.e., carbon,nitrogen and phosphor containing the domestic wastewater is proposed to carryout biological method of an anoxic-aerobic reactor therein these types ofpollutants should be consecutively processed in three steps. Firstly, eliminate thecarbonaceous matter in the aerobic reactor. Secondly, to remove the carbonaceousand nitrogenous matters, it is necessary to modify the reactor’s nature from theaerobic condition to an anoxic-aerobic reactor. And finally, when the cycle ofnitrification-denitrification is stable to achieve the target’s efficiency of reactor byadding the ferric iron into the activated sludge, it can be continued to remove thecarbonaceous, nitrogenous and phosphorous matters simultaneously. Theefficiency of carbonaceous and nitrogenous matters removal was confirmed withthe effluent standard, COD is less than 100 mgO2/L and the value of globalnitrogen is less than 10 mgN/L. The effectiveness of suspended matter removal ishigher than 90% and the decantation of activated sludge is very good asidentifying the Molhman’s index is below of 120 mL/L. The total phosphorusmatter removal is more effective than the soluble phosphorus matter. Bymaintaining the reactor’s nature at the suitable condition, identifying the range ofpH between 6.92 and 7.16 therefore the excellent abatement of phosphor of about80% is achieving with the molar Fe/P ratio of 1.4.