Effects of Stepwise Adjustment of C/N during the Start-Up of Submerged Membrane Bioreactors (SMBRs) on the Aerobic Denitrification of Wastewater

Zhang, Yinan; Fang, Yuxin; Wang, Banglong; Zhang, Hangjun; Ding, Jiafeng

doi:10.3390/w13223251

Cited by 9 publications

(4 citation statements)

References 55 publications

(58 reference statements)

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“…Correlation heat map analysis (Figure 5B) showed that Rhodanobacter was positively correlated with C/N and EC and negatively correlated with the pH. This was consistent with previous studies on Rhodanobacter [40,41]. This result indicated that the growth of Rhodanobacter requires the environment to provide sufficient sources of carbon and a suitable pH.…”

Section: The Correlation Between Microbial Action and Environmental F...supporting

confidence: 90%

The Substitution of Sphagnum for Peat as a Culture Substrate Reduces N2O Emissions from Vegetable Production Systems

Liang,

Wang,

Zhang

et al. 2024

Agronomy

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Peat-based substrates have been widely used in greenhouse vegetable production (GVP). However, peat is a non-renewable resource, and there is a problem with N2O emissions when it is used in greenhouse vegetable production due to the application of large quantities of nutrient solutions. Sphagnum (SP) is a precursor substance and a renewable resource for peat formation, and it has good physical and chemical properties. However, there has been no study on the effect of using sphagnum to replace peat in greenhouse vegetable production on N2O emissions. Therefore, this study used a peat substrate as the control treatment (CK), with sphagnum replacing peat at 25% (25SP), 50% (50SP), 75% (75SP), and 100% (100SP) in six treatment groups. Moreover, lettuce was used as the experimental subject in potting experiments, and the physicochemical properties, N2O emissions, N2O isotope δ value, and N2O-related microbial activity and community structures were determined using different treatments. Compared with the CK treatment, the 25SP treatment significantly reduced N2O emissions by 55.35%, while the 75SP treatment significantly increased N2O emissions by 67.76%. The 25SP treatment reduced N2O to N2 to the highest extent and demonstrated the lowest contribution of fungal denitrification (FD) and bacterial nitrification (BN) processes, thereby resulting in lower N2O emissions. In contrast, NH4+ and NO3− were the main substrates for N2O emissions; the 75SP treatment had higher NH4+ and NO3− contents and a lower relative abundance of the nosZ gene, thereby resulting in higher N2O emissions. In addition, N2O production and reduction were dominated by bacterial denitrification for all treatments. Thus, this study analyzed the community composition of denitrifying bacterial genera and their association with physicochemical properties. The results indicated that the dominant denitrifying genus in the peat substrate was Rhodanobacter and that sphagnum replacement reduced the relative abundance of Rhodanobacter. The dominant genus was Massilia at 100% sphagnum replacement. More importantly, Rhodanobacter was correlated with C/N and electrical conductivity (EC), whereas Massilia was affected by NH4+ and the water-filled pore space (WFPS). Therefore, different denitrification-dominant genera were affected by different environmental factors, which indirectly affected N2O emission. In summary, the 25SP treatment was able to improve nitrogen use efficiency and had no significant effect on lettuce yield. Therefore, 25% sphagnum replacement is the most suitable percentage for peat replacement.

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Section: The Correlation Between Microbial Action and Environmental F...supporting

confidence: 90%

The Substitution of Sphagnum for Peat as a Culture Substrate Reduces N2O Emissions from Vegetable Production Systems

Liang,

Wang,

Zhang

et al. 2024

Agronomy

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“…Wastewater must contain sufficient organic matter in both quantity and quality for biological nutrient removal processes to occur. Heterotrophic microorganisms responsible for phosphorus removal also require sources of carbon/energy; thus, a higher C/N ratio is needed to achieve the simultaneous removal of nitrogen and phosphorus [37,63,64].…”

Section: Simultaneous Nitrification and Denitrification (Snd)mentioning

confidence: 99%

Excess of Nutrients in Prefabricated or Compact Wastewater Treatment Plants: Review, Solution Alternative, and Modeling for Verification

Díaz,

Blanco,

Chandia-Jaure

et al. 2024

Water

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Chile has numerous areas that lack sewage collection, including in the capital city. Sanitation in these cases is managed through individual solutions like septic tanks or small wastewater treatment plants (WWTPs) that use biological treatment, usually activated sludge with extended aeration. In general, the design of these systems adheres to the quality standards mandated by regulations for discharge, infiltration, or irrigation. In this scenario, traditional methods like increasing dissolved oxygen (DO) or hydraulic retention time (HRT) were unable to effectively reduce excessive nutrients. Therefore, literature related to nutrient excess and denitrification systems is consulted and reviewed to compile different solutions suitable for the presented issue. Potential solutions were modeled and verified using the free simulation software WRc STOAT. The software accurately predicted the unsatisfactory results of the current setup and provided parameters for the proposed modifications. Experience, precise user definition, influential characteristics, and modeling are essential in the design of WWTPs.

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“…At the same time, the NO 3 − -N concentration in the effluent increased gradually and was maintained at 20.20 ± 1.15 mg/L. It might be that the concentration of organic matter in urban sewage was too low, which led to the inactivation of denitrifying bacteria and the loss of electron donors, resulting in the inhibition of denitrifying bacteria [36]. In the whole process, NH 4 + -N was efficiently and stably removed, indicating that the SMBR was in an efficient denitrification state since its successful start-up.…”

Section: Nitrogen and Tp Monitoringmentioning

confidence: 99%

Treatment Performance of Municipal Sewage in a Submerged Membrane Bioreactor (SMBR) and Mechanism of Biochar to Reduce Membrane Fouling

Jiang

Guo

2023

Sustainability

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Submerged membrane bioreactors (SMBRs) are a promising technology for municipal sewage treatment, but membrane fouling has limited their development. In this study, biochar (BC), which has a certain adsorption capacity, was added to an SMBR to investigate its potential in treating municipal sewage and alleviating membrane fouling. The results showed that the average removal rates of ammonia nitrogen (NH4+-N), total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD) were 94.38%, 59.01%, 44.15% and 83.70%, respectively. After BC was added and operation was stable, the ratio of mixed liquor volatile suspended solids to mixed liquor suspended solids (MLVSS/MLSS) was maintained between 0.78 and 0.81. The concentrations of soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) were stabilized between 63.05 ± 8.49 mg/L and 67.12 ± 1.54 mg/L. Trans-membrane pressure (TMP) and scanning electron microscopy (SEM) analyses showed that BC reduced the TMP by reducing the thickness and compactness of the cake layer on the membrane surface. The high-throughput sequencing results showed that the microorganisms associated with biofilm formation (proteobacteria, γ-proteobacteria and α-proteobacteria) were significantly reduced in the BC-enhanced SMBR system. BC promoted the enrichment of functional microorganisms such as Chloroflexi, Acidobacteriota, Anaerolineae and Planctomycetes. Compared with traditional anti-fouling methods, the results of this study may provide a low-cost membrane fouling mitigation method for industrial applications of SMBRs.

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Effects of Stepwise Adjustment of C/N during the Start-Up of Submerged Membrane Bioreactors (SMBRs) on the Aerobic Denitrification of Wastewater

Cited by 9 publications

References 55 publications

The Substitution of Sphagnum for Peat as a Culture Substrate Reduces N2O Emissions from Vegetable Production Systems

The Substitution of Sphagnum for Peat as a Culture Substrate Reduces N2O Emissions from Vegetable Production Systems

Excess of Nutrients in Prefabricated or Compact Wastewater Treatment Plants: Review, Solution Alternative, and Modeling for Verification

Treatment Performance of Municipal Sewage in a Submerged Membrane Bioreactor (SMBR) and Mechanism of Biochar to Reduce Membrane Fouling

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