Organic matter and concentrated nitrogen removal by shortcut nitrificationand denitrification from mature municipal landfill leachate
ZHANG Shu-jun , PENG Yong-zhen , WANG Shu-ying , ZHENG Shu-wen , GUO Jin
DOI:
Received July 16, 2006,Revised December 04, 2006, Accepted , Available online
Volume 19,2007,Pages 647-651
- Summary
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An UASB+Anoxic/Oxic (A/O) system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and
high ammonia concentration. To make the best use of the biodegradable COD in the leachate, the denitrification of NOx??-N in the
recirculation e uent from the clarifier was carried out in the UASB. The results showed that most biodegradable organic matters were
removed by the denitrification in the UASB. The NH4
+-N loading rate (ALR) of A/O reactor and operational temperature was 0.28–
0.60 kg NH4
+-N/(m3 d) and 17–29°C during experimental period, respectively. The short-cut nitrification with nitrite accumulation
e ciency of 90%–99% was stabilized during the whole experiment. The NH4
+-N removal e ciency varied between 90% and 100%.
When ALR was less than 0.45 kg NH4
+-N/(m3 d), the NH4
+-N removal e ciency was more than 98%. With the influent NH4
+-N
of 1200–1800 mg/L, the e uent NH4
+-N was less than 15 mg/L. The shortcut nitrification and denitrification can save 40% carbon
source, with a highly e cient denitrification taking place in the UASB. When the ratio of the feed COD to feed NH4
+-N was only 2–3,
the total inorganic nitrogen (TIN) removal e ciency attained 67%–80%. Besides, the sludge samples from A/O reactor were analyzed
using FISH. The FISH analysis revealed that ammonia oxidation bacteria (AOB) accounted for 4% of the total eubacterial population,
whereas nitrite oxidation bacteria (NOB) accounted only for 0.2% of the total eubacterial population.
