Free nitrous acid inhibition on anoxic phosphorus uptake and denitrification by poly‐phosphate accumulating organisms

Zhou, Yan; Pijuan, Maite; Yuan, Zhiguo

doi:10.1002/bit.21458

Cited by 133 publications

(86 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pijuan et al 5 showed that the aerobic phosphorus uptake was inhibited by 50% when FNA reached 0.52 3 10 23 mg HNO 2 -N/L. Anoxic phosphorus uptake was also significantly affected by FNA presence 14 , and 0.02 mg HNO 2 -N/L would cause the complete loss of anoxic phosphorus uptake 11 . Furthermore, anaerobic metabolisms of PAOs were also severely affected by FNA, and Ye et al 8 demonstrated that FNA had an adverse effect on carbon source uptake even at 1.0 3 10 23 mg HNO 2 -N/L.…”

mentioning

confidence: 99%

“…Especially in some WWTPs that achieve nitrogen removal via the nitrite pathway, the accumulated concentration could reach up to 40 mg/L 10 . Previous researchers considered that the intermediate of nitrification and denitrification (i.e., nitrite) caused seriously inhibition on the metabolisms of PAOs, but recently there have been increasing evidences showing that FNA, the protonated form of nitrite, rather than nitrite is the actual inhibitor 5,11,12 . For example, it was reported that FNA could inhibit aerobic phosphorus uptake seriously at a low level of 0.5 3 10 23 mg HNO 2 -N/L 11 , and more than 1.5 3 10 23 mg HNO 2 -N/L could result in the complete loss of aerobic phosphorus uptake 13 .…”

mentioning

confidence: 99%

See 1 more Smart Citation

Characterization of Pure Cultures Isolated from Sulfamethoxazole-acclimated Activated Sludge with Respect to Taxonomic Identification and Sulfamethoxazole Biodegradation Potential

2016

Environmental Engineering and Activated Sludge Processes

View full text Add to dashboard Cite

Free nitrous acid (FNA), which is the protonated form of nitrite and inevitably produced during biological nitrogen removal, has been demonstrated to strongly inhibit the activity of polyphosphate accumulating organisms (PAOs). Herein we reported an efficient process for wastewater treatment, i.e., the oxic/anoxic/ oxic/extended-idle process to mitigate the generation of FNA and its inhibition on PAOs. The results showed that this new process enriched more PAOs which thereby achieved higher phosphorus removal efficiency than the conventional four-step (i.e., anaerobic/oxic/anoxic/oxic) biological nutrient removal process (41 6 7% versus 30 6 5% in abundance of PAOs and 97 6 0.73% versus 82 6 1.2% in efficiency of phosphorus removal). It was found that this new process increased pH value but decreased nitrite accumulation, resulting in the decreased FNA generation. Further experiments showed that the new process could alleviate the inhibition of FNA on the metabolisms of PAOs even under the same FNA concentration.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Characterization of Pure Cultures Isolated from Sulfamethoxazole-acclimated Activated Sludge with Respect to Taxonomic Identification and Sulfamethoxazole Biodegradation Potential

2016

Environmental Engineering and Activated Sludge Processes

View full text Add to dashboard Cite

show abstract

“…The cells then need more energy to maintain the proton balance and consequently less energy is available for metabolism and growth (Rottenberg, 1990). Studies of enrichments of the PAO Accumulibacter show that during exposure to higher FNA concentrations the cellular ATP levels are more rapidly consumed (Zhou et al, 2007, Zhou et al, 2010. The rapid depletion of intracellular ATP is presumed to be responsible for cell lysis (Schimz, 1980).…”

Section: Mechanisms Of Fna-induced Inhibitory and Biocidal Effects Ofmentioning

confidence: 99%

FNA-based pre-treatment of primary, secondary and digested sludge

Zhang¹

View full text Add to dashboard Cite

Wastewater treatment plants (WWTP) are widely applied in practice to remove nutrients from wastewater and to minimize its impact when discharged to the environment. However, approximately 1/3 of the total organic carbon is converted into waste activated sludge (WAS), the treatment and disposal of which accounts for up to 20~60% of the overall costs of the wastewater treatment due to its poor biodegradability. In order to achieve sludge reduction and maximize the methane production from WAS, pre-treatment is often required. The overall objective of this thesis is to investigate the effects of free nitrous acid (FNA, i.e. HNO2) pre-treatment on the biodegradability of primary, secondary and digested sludges in WWTPs and also to reveal the mechanisms by which FNA works to improve the sludge degradability.The feasibility of a novel pre-treatment strategy using combined FNA and hydrogen peroxide (H2O2) to enhance methane production from WAS was investigated. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10~80 mg/g TS), and their combinations followed by biochemical methane potential (BMP) tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59~83%, compared to 13~23% and 56% with H2O2 pretreatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with an increase of up to 163% in rapidly biodegradable fraction with combined pre-treatment. In some WWTPs, primary sludge (PS) and WAS are commonly mixed and digested simultaneously in the anaerobic digester. In order to reveal whether and how the PS and WAS should be jointly II treated by FNA in WWTPs, the effects and mechanisms of FNA pre-treatment on methane production from PS was studied. Full-scale derived PS was pre-treated with FNA at concentrations of 0~3.85 mg N/L followed by BMP tests. FNA treated PS was then centrifuged to separate the supernatant from the solid phase and BMP tests were performed on both fractions. The FNA pre-treatments resulted in methane potential reductions of 1~7%. The methane production from both supernatant and solid phases had also decreased. The molecular weight and chemical structure analysis of components of the soluble phase showed very limited release of readily biodegradable substances from PS with the FNA pre-treatment. As the FNA pre-treatment compromised the methane production from PS, this indicates that FNA-based sludge pre-treatment technology should be implemented solely on WAS to maximise the methane production from the two sludge streams.The ever increasing production of the two sludge streams occurring due to increased population will create challenges for handling, treatment and disposal of the sludge at current capacity, making it difficult to achieve the desirable sludge reduction efficiency in anaerobic digestion. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, so far this has had on...

show abstract

“…Zhou et al (2007) found that nitrite, at a concentration ranging from 35.9 to 103.5 mg N/L, was able to inhibit the anoxic phosphorus (P) uptake in enhanced biological phosphorus removal (EBPR)…”

Section: Nitrite Application In Wastewater Industrymentioning

confidence: 99%

Novel sludge treatment technology enhances toxic metal removal, pathogen reduction, sludge digestibility and dewaterability

Du¹

View full text Add to dashboard Cite

The activated sludge process (ASP) is a widely applied technology for biological wastewater treatment. The sludge production from the ASP is enormous and its management contributes typically 30 -50% of the total operating costs of the wastewater treatment plant (WWTP). To develop a more cost-effective and sustainable wastewater treatment process, reduced sludge generation, improved energy recovery and beneficial biosolids reuse for nutrient recovery are key optimisation targets. Anaerobic digestion (AD) is widely adopted for sludge stabilisation and energy recovery through biogas production. However, the poor digestibility of sludge, especially waste activated sludge (WAS), often reduces the AD efficiency. Sludge application on agricultural land provides an opportunity for the beneficial reuse of organic matter and nutrients, particularly nitrogen and phosphorus. However, toxic metal contaminants, including Cd, Cr, Cu, Ni, Pb and Zn, often limit land application of these biosolids. Hence there is a significant demand for innovative sludge treatment solutions that can remove toxic metals and improve sludge digestibility to maximise the beneficial reuse potential and minimise costs related to transportation and disposal. In this thesis, a novel sludge treatment technology concept was developed with integrating nitrite addition and in situ electrochemical acid and alkali production, whereby metal removal, pathogen reduction, sludge digestibility and dewaterability were all enhanced at the same time.First, the effect of nitrite addition on metal removal from acidified sludge was investigated using WAS from three different full-scale WWTPs. It was found that acidification to pH 2 by sulfuric acid achieved Zn removal of around 70%, but only 3 -7% of Cu was removed. Nitrite addition of 20 mg NO 2 --N/L (equal to 19.2 mg HNO 2 -N/L) to the acidified WAS substantially enhanced Cu removal to 45-64%, while Zn removal was also increased to over 81%. Metal distribution analysis using sequential chemical extraction revealed that the improvement of Cu and Zn removal was mainly due to the release of the organically bound metal fraction. Subsequent process optimisation demonstrated that a nitrite addition of 10 mg NO 2 --N/L and 5 hour exposure time was sufficient for metal removal enhancement for WAS at pH 2.To avoid the purchase, transport, storage and handling of corrosive acid and alkali for the treatment as well as minimising possible occupational health and safety issues with the treatment, a threecompartment electrochemical system (ES) was employed for the in situ sludge acidification and alkali generation. Acidification (to pH 2) of WAS and alkali production were achieved in the anode and cathode compartment, respectively, with a current efficiency of 85% for both anode and cathode processes. Maintaining the optimised WAS treatment conditions (5 h at pH 2 with 10 mg iii NO 2 --N/L) achieved solubilisation of 60 ± 2% Cu and 86 ± 1% Zn, which is even higher than what was achieved in the treatment with external acid...

show abstract

Free nitrous acid inhibition on anoxic phosphorus uptake and denitrification by poly‐phosphate accumulating organisms

Cited by 133 publications

References 36 publications

Characterization of Pure Cultures Isolated from Sulfamethoxazole-acclimated Activated Sludge with Respect to Taxonomic Identification and Sulfamethoxazole Biodegradation Potential

Characterization of Pure Cultures Isolated from Sulfamethoxazole-acclimated Activated Sludge with Respect to Taxonomic Identification and Sulfamethoxazole Biodegradation Potential

FNA-based pre-treatment of primary, secondary and digested sludge

Novel sludge treatment technology enhances toxic metal removal, pathogen reduction, sludge digestibility and dewaterability

Contact Info

Product

Resources

About