PROCESS FOR TREATING MUNICIPLE WASTEWATER EMPLOYING TWO SEQUENCING BIOFILM BATCH REACTORS

摘要

A method is provided for removing BOD and ammonium from wastewater in a mainstream process that includes deammonification. Wastewater including BOD and ammonium is directed to a first sequence batch reactor (SBBR). The wastewater is treated in the first SBBR and in the process nitrite is accumulated such that the wastewater includes a nitrite-to-ammonium stoichiometric ratio that enables anammox bacteria to effectively remove ammonium and nitrite from the wastewater. Thereafter the wastewater is directed the wastewater from the first SBBR to a second SBBR. The second SBBR is operated under anoxic conditions and employs anammox bacteria to remove ammonium and nitrite from the wastewater. In certain embodiments, a pre-denitrification step or process is employed in the first SBBR to remove BOD. In addition, in certain embodiments, the second SBBR includes an oxic phase for converting some ammonium to nitrite and, in some cases, an external carbon source is added to the wastewater under anoxic conditions to reduce the concentration of the nitrate in the wastewater.