J. Morgansagastume et al., ANAEROBIC-ANOXIC-AEROBIC PROCESS WITH RECYCLING AND SEPARATED BIOMASSFOR ORGANIC-CARBON AND NITROGEN REMOVAL FROM WASTE-WATER, Environmental technology, 15(3), 1994, pp. 233-243
A study was made of an anaerobic-anoxic-aerobic process with recycling
and different biomasses to maximize the.removal of organic material a
nd nitrogen from domestic wastewater by varying the recycling ratio be
tween the aerobic and anoxic reactors. The anaerobic and anoxic reacto
rs were UASB type and the aerobic was submerged filter packed with PVC
tubes. With a 3:1 recycling ratio, 80% of the TOCs, 62% of N and 90%
of TSS were removed. The concentration of TSS in the treated water was
lower than 20 mg L-1 (12 mg TSS L-1) making unnecessary the use of fi
nal settlers. The concentration of TOCs and N-NH4 in the system efflue
nt operating with a 3:1 ratio was 7 and 4.6 mg L-1, respectively. The
proposed system may be used in treatment schemes designed to provide w
ater for reuse or discharge at low operational cost.