Abstract:
This research is to study the efficiency of nitrogen removal from high salinity wastewater by the
process of Anaerobic Ammonium Oxidation (ANAMMOX) in an 8-liter sequencing batch reactor
(SBR). Three different solid retention time (SRT) of 32,64 days and without solid withdrawal were
applied. Salinity was supplied in two modes, i.e., gradually and shock additions. The hydraulic
retention time (HRT) was kept at 2.5 days. Ammonia and nitrite were added at the ratio of l:1. The
ammonia concentration in the synthetic wastewater was 200 mg NIL the results showed that as the
SRT lowered from no solid withdrawal to 64 and 32 days, the nitrogen removal efficiencies were
reduced from 85.36?6.13% to 69.35?2.07 and 56.1O?0.94%, respectively. The specific ammonia
utilization rates were 0.181, 0.166, and 0.129 g N g VSS-J d-I while the specific ANAMMOX
ammonia utilization rates were 0.171. 0.125, and 0.097 g N g VSS' I d-I for no solid withdraw, and
SRT of 64, and 32 days, respectively. Furthermore, the uptake ratio of ammonia to nitrite from the
experiments were 1.36, 1.0 I, and 1.05 for without solid withdrawal, and SRT of 64 and 32 days,
respectively, which closed to the ANAMMOX stoichiometric ratio of 1.32. As the salinity increased
from 0 to 5 and 10 ppt in the gradually addition mode with no solid withdrawal, nitrogen removal
efficiencies decreased from 83.21?1.4l% to 79.23?1.29 and 33.67?6.69%, respectively. The
efficiencies also decreased in the run with 32 days of SRT from 52.45?2.24% to 43.87?0.80 and
l5.02?2.14%, respectively. For the gradually addition mode, the specific ANAMMOX ammonia
utilization rates without solid withdrawal and SRT of 32 days with the salinity of 0, 5, and 10 ppt
-I -I -) -I were 0.169, 0.155. and 0.105 g N g VSS d and 0.096, 0.086, and 0.045 g N g VSS d,
respectively. In the salinity shock mode, the specific ANAMMOX ammonia utilization rates
without solid withdrawal and SRT of32 days with the salinity of 0, 5, and 10 ppt were 0.128, 0.082,
-( -I -I -1 and 0.037 g N g VSS d and 0.083, 0.036, and 0.028 g N g VSS d, respectively. The
fluorescence in situ hybridization (FISH) analysis revealed the existence of ANAMMOX bacteria,
Nitrosomonas spp., Nitrobacter spp., and Nitrospira spp.