Authors: Mingchuan Zhang Peadar G Lawlor Guangxue Wu Brendan Lynch Xinmin Zhan
Publish Date: 2011/06/05
Volume: 34, Issue: 9, Pages: 1049-1056
Abstract
The performance of an intermittently aerated sequencing batch reactor IASBR technology was investigated in achieving partial nitrification organic matter removal and nitrogen removal from separated digestate liquid after anaerobic digestion of pig manure The wastewater had chemical oxygen demand COD concentrations of 11540 ± 860 mg/L 5day biochemical oxygen demand BOD5 concentrations of 2900 ± 200 mg/L and total nitrogen TN concentrations of 4041 ± 59 mg/L with low CODN ratios 29 and BOD5COD ratios 025 Synthetic wastewater simulating the separated digestate liquid with similar COD and nitrogen concentrations but BOD5 of 11500 ± 100 mg/L was also treated using the IASBR technology At a mean organic loading rate of 115 kg COD/m3 d and a nitrogen loading rate of 038 kg N/m3 d the COD removal efficiency was 898 in the IASBR IASBR1 treating digestate liquid and 99 in the IASBR IASBR2 treating synthetic wastewater The IASBR1 effluent COD was mainly due to inert organic matter and can be further reduced to less than 40 mg/L through coagulation The partial nitrification efficiency of 71–79 was achieved in the two IASBRs and one cause for the stable longterm partial nitrification was the intermittent aeration strategy Nitrogen removal efficiencies were 765 and 97 in IASBR1 and IASBR2 respectively The high nitrogen removal efficiencies show that the IASBR technology is a promising technology for nitrogen removal from low CODN ratio wastewaters The nitrogen balance analysis shows that 594 and 743 of nitrogen removed was via heterotrophic denitrification in the nonaeration periods in IASBR1 and IASBR2 respectively
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