Partial nitrification and nutrient removal in intermittently aerated sequencing batch reactors treating separated digestate liquid after anaerobic digestion of pig manure

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 11,540 ± 860 mg/L, 5-day biochemical oxygen demand (BOD(5)) concentrations of 2,900 ± 200 mg/L and total nitrogen (TN) concentrations of 4,041 ± 59 mg/L, with low COD:N ratios (2.9) and BOD(5):COD ratios (0.25). Synthetic wastewater, simulating the separated digestate liquid with similar COD and nitrogen concentrations but BOD(5) of 11,500 ± 100 mg/L, was also treated using the IASBR technology. At a mean organic loading rate of 1.15 kg COD/(m(3) d) and a nitrogen loading rate of 0.38 kg N/(m(3) d), the COD removal efficiency was 89.8% in the IASBR (IASBR-1) treating digestate liquid and 99% in the IASBR (IASBR-2) treating synthetic wastewater. The IASBR-1 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 long-term partial nitrification was the intermittent aeration strategy. Nitrogen removal efficiencies were 76.5 and 97% in IASBR-1 and IASBR-2, respectively. The high nitrogen removal efficiencies show that the IASBR technology is a promising technology for nitrogen removal from low COD:N ratio wastewaters. The nitrogen balance analysis shows that 59.4 and 74.3% of nitrogen removed was via heterotrophic denitrification in the non-aeration periods in IASBR-1 and IASBR-2, respectively.

Effect of Aeration Rates on Removals of Organic Carbon and Nitrogen in Small Onsite Wastewater Treatment System (Johkasou)

“…These results indicate that high DO concentration favors conditions for niftrifier bacteria to oxidize the ammonium and improve the removal percentages of TN and NH 4 + -N. However, decreasing aeration rate caused high dissolved organic carbon concentrations, which inhibited nitrification both in the anoxic and oxic zones and thereby increased the concentration of nitrogen in the effluent. Similar results were reported by [3], [22], [23].…”

“…Similar results were reported by [3], [15], [16]. Therefore, it is suggested that Johkasou system is recommended to applied continuous oxygen supply at high rate to achieve simultaneously nitrification.…”

“…A biological system is mostly eliminated the nitrogen compounds through combination processes of nitrification and denitrification. This system consists of two successive steps: 1) autotrophic nitrification in which NH 4 + -N is oxidized to nitrite (NO 2 --N) and then nitrate (NO 3 --N) under aerobic condition; and 2) heterotrophic denitrification in which NO 3 --N is reduced to nitrogen gas (N 2 ) by heterotrophic denitrifiers under anoxic conditions with organic carbon as the electron donor [3].…”

Assessment of Phosphorus Recovery from Swine Wastewater in Beijing, China

“…In recent years, most swine pollution treatment focuses on COD and NH 4 + -N removal [31]. However, P is also an important factor for swine wastewater that relates to water environment security.…”

Response of nitrite accumulation and microbial community to free ammonia and dissolved oxygen treatment of high ammonium wastewater

“…High ammonium (NH 4 + -N) wastewater (including animal production wastewater, landfill leachate, and anaerobic digestate of waste sludge) has harmful effects on bodies of water and aquatic plants without proper treatment, which has been widely studied with regard to biological nitrogen removal (BNR) (Zhang et al 2007;Zhang et al 2011;Guo et al 2010). Shortcut nitrification and denitrification (SND) and anaerobic ammonium oxidation (Anammox) are two BNR processes suitable for the treatment of high ammonium wastewater.…”