The treatment of synthetic landfill leachate and raw landfill leachate were investigated using two sets of 3 L aerobic sequencing batch reactors (SBR): activated sludge SBR (ASBR) and granular SBR (GSBR).
In synthetic young landfill leachate treatment, GSBR was more efficient in nitrogen and carbon removal than ASBR. During the steady period of the experiment, 99% total ammonium nitrogen (TAN) was removed through nitritation and nitrification in GSBR with an average influent TAN concentration of 498 mg/L. On the contrary, complete nitrification was not achieved in ASBR with a nitrification efficiency of 77±10%. GSBR also presented higher efficiency in denitrification and COD removal compared to ASBR. Phosphorus removal efficiency was almost identical in both reactors.
Synthetic old landfill leachate treatment using GSBR maintained the stable COD removal efficiency at 66%, when the ammonia nitrogen to the maximum of 465±46 mg/L. The ASBR required a start-up of at least 30 days and removed 59±9% of COD when an influent ammonia nitrogen concentration about 200 mg/L. The GSBR was also more efficient than the ASBR for nitrogen removal. The granular sludge reached a maximum ammonia removal of 95±7%, whereas 96±5% was achieved by ASBR. The phosphorus removal was likely affected by the free nitrous acid (FNA) and the low biodegradability of tannic acid.
In raw landfill leachate treatment, the total ammonia nitrogen (TAN) removal efficiency was in GSBR approximately 99.7%. However, the ASBR treatment did not show a consistent performance in TAN removal. TAN removal efficiency decreased with increasing ammonia concentration in the influent. Nitrification in GSBR was partially inhibited at FA concentrations of 48 to 57 mg/L, which was two times more than the FA concentration that inhibited nitrification in ASBR. In terms of chemical oxygen demand (COD) removal, low removal efficiencies of 17% and 26% were observed in ASBR and GSBR, respectively. The low COD removal efficiencies were associated with the refractory organic content of the leachate used in this study, which resulted in a poor phosphorous removal performance as well.
Overall, aerobic granular sludge showed a better performance in removing nutrients and organic matter from young or old landfill leachate, being more efficient than the conventional suspended growth activated sludge. Therefore, the use of AGS for leachate treatment should be encouraged. Further investigations should also be addressed, especially with a focus on improving SND and phosphorus removal efficiencies. / May 2017
| Identifer | oai:union.ndltd.org:MANITOBA/oai:mspace.lib.umanitoba.ca:1993/32147 |
| Date | 09 March 2017 |
| Creators | Ren, Yanan |
| Contributors | Yuan, Qiuyan (Civil Engineering), Oleszkiewicz, Jan (Civil Engineering) Sparling, Richard (Microbiology) |
| Source Sets | University of Manitoba Canada |
| Detected Language | English |
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