Partial nitritation at elevated loading rates: design curves and biofilm characteristics

Schopf, Alexander; Delatolla, Robert; Kirkwood, Kathlyn M.

doi:10.1007/s00449-019-02177-8

Cited by 8 publications

(11 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While NOB suppressions have been observed in granules or biofilm systems with high loading rates, , the role of high hydraulic loading rates on the NOB control was not clearly recognized or understood. The oxygen competition between AOB and NOB was believed to be the cause to NOB suppressions .…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The hydraulic loading rate is of vital importance for wastewater treatment and has been extensively investigated. More recently, some studies reported that elevated hydraulic loading rate contributes to NOB suppression and subsequent partial nitritation in moving bed biofilm reactors , or aerobic granular reactors. − It was speculated that oxygen competition could have resulted in the observed nitritation . However, in many more studies, increased loading did not lead to NOB suppressions or nitritation. − No consensus has been reached on whether high hydraulic loading rates can contribute to NOB suppressions; and more importantly, the underlying factors remain to be investigated.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

High Hydraulic Loading Rates Favored Mainstream Partial Nitritation: Experimental Demonstration and Model-Based Analysis

Duan

Zheng

et al. 2023

ACS EST Water

View full text Add to dashboard Cite

Partial nitritation is required to provide nitrite for the anammox reaction in an autotrophic nitrogen removal process, which has been considered crucial to achieving energy-positive mainstream sewage treatment. In this study, three lab-scale reactors were operated to treat wastewaters with low ammonium concentrations at high hydraulic loading rates (nitrogen loading rates of 0.36 kg N/d/m3). Long-term experiments repeatedly demonstrated that a high hydraulic loading rate favored the startup of partial nitritation, as indicated by the nitrite buildup and effluent nitrite accumulation ratio maintained above 95% over 2 months. Despite many advantages of high loading rates, a major drawback resides in the process instability, i.e., unsustained nitrite-oxidizing bacteria (NOB) suppression. To elucidate the occurrence and disappearance of the partial nitritation, mathematical modeling was implemented. An integrated fixed-film activated sludge biofilm model was developed, calibrated, and validated based on the observed coexistence of granules and floccular sludge. Model-based analysis suggested that high hydraulic loading rates suppressed NOB likely via intensifying granule surface sloughing and restricting oxygen penetration. Based on the unraveled mechanisms, operational strategies were proposed and tested with mathematical models. The mechanisms illustrated in this work can guide the development of new operational strategies to facilitate mainstream partial nitritation and the anammox process.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High Hydraulic Loading Rates Favored Mainstream Partial Nitritation: Experimental Demonstration and Model-Based Analysis

Duan

Zheng

et al. 2023

ACS EST Water

View full text Add to dashboard Cite

show abstract

“…In recent studies, an elevated TAN loading rate, as a means of a passive and low operational design strategy, has been shown to achieve stable partial nitritation rates within a two-stage configured MBBR system (Schopf et al, 2019(Schopf et al, , 2021Ikem et al, 2023). Schopf et al (2019Schopf et al ( , 2021 achieved stable and robust partial nitritation at an elevated TAN loading rate of 6.5 g TAN/m 2. d in an MBBR system fed with TAN concentration of 125mg TAN/L, simulating TAN concentrations observed in industrial wastewaters. In this system, stable partial nitritation was attributed to the morphological impacts resulting from operating at an elevated TAN loading rate that could allow for NOB activity to be effectively suppressed (Schopf et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, further investigation of biofilm characteristics, embedded cells, and microbiome response is needed to understand nitrite oxidation suppression mechanism responsible for stable partial nitritation of mainstream elevated loaded MBBR systems. Although previous work has investigated the mechanism and method of nitrite oxidation suppression caused by employing elevated TAN loading rate for partial nitritation control, these studies were performed at higher influent TAN concentrations not typically observed in mainstream municipal wastewater (Schopf et al, 2019(Schopf et al, , 2021. Thus, there is a significant knowledge gap and a need to investigate further the mechanism of nitrite oxidation suppression in the elevated loaded partial nitritation system that would ensure high performance and long-term operational stability under mainstream conditions.…”

Section: Introductionmentioning

confidence: 99%

Design strategy and mechanism of nitrite oxidation suppression of elevated loading rate partial nitritation system

2023

Self Cite

View full text Add to dashboard Cite

There is a current need for a low operational intensity, effective and small footprint system to achieve stable partial nitritation for subsequent anammox treatment at mainstream municipal wastewaters. This research identifies a unique design strategy using an elevated total ammonia nitrogen (TAN) surface area loading rate (SALR) of 5 g TAN/m2.d to achieve cost-effective, stable, and elevated rates of partial nitritation in a moving bed biofilm reactor (MBBR) system under mainstream conditions. The elevated loaded partial nitritation MBBR system achieves a TAN surface area removal rate (SARR) of 2.01 ± 0.07 g TAN/m2.d and NO2−-N: NH4+-N stoichiometric ratio of 1.15:1, which is appropriate for downstream anammox treatment. The elevated TAN SALR design strategy promotes nitrite-oxidizing bacteria (NOB) activity suppression rather than a reduction in NOB population as the reason for the suppression of nitrite oxidation in the mainstream elevated loaded partial nitritation MBBR system. NOB activity is limited at an elevated TAN SALR likely due to thick biofilm embedding the NOB population and competition for dissolved oxygen (DO) with ammonia-oxidizing bacteria for TAN oxidation to nitrite within the biofilm structure, which ultimately limits the uptake of DO by NOB in the system. Therefore, this design strategy offers a cost-effective and efficient alternative for mainstream partial nitritation MBBR systems at water resource recovery facilities.

show abstract

Two moving bed biofilm reactors in series for carbon, nitrogen, and phosphorous removal from high organic wastewaters

Tsitouras

Al-Ghussain

Delatolla

2021

Journal of Water Process Engineering

View full text Add to dashboard Cite

Partial nitritation at elevated loading rates: design curves and biofilm characteristics

Cited by 8 publications

References 47 publications

High Hydraulic Loading Rates Favored Mainstream Partial Nitritation: Experimental Demonstration and Model-Based Analysis

High Hydraulic Loading Rates Favored Mainstream Partial Nitritation: Experimental Demonstration and Model-Based Analysis

Design strategy and mechanism of nitrite oxidation suppression of elevated loading rate partial nitritation system

Two moving bed biofilm reactors in series for carbon, nitrogen, and phosphorous removal from high organic wastewaters

Contact Info

Product

Resources

About