How do the influent COD/Nitrogen and internal recirculation ratios affect the oxidation ditch type pre-anoxic landfill leachate treatment?

Çakirgöz, Mücahid; Bayrakdar, Alper; Çallı, Barış

doi:10.1016/j.jenvman.2020.111598

Cited by 7 publications

(5 citation statements)

References 32 publications

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“…Therefore, Eq. 1 was obtained: The original definition of IRR in an oxidation ditch is the ratio of circulation flow rate to influent flow rate (Insel et al, 2005;Tang and Huang, 2006;Guo et al, 2013;Cakirgöz et al, 2021), so IRR could be described as Eq. 2:…”

Section: Numerical Relationship Between Irr and Tmentioning

confidence: 99%

“…A few researchers also began to study the internal recirculation characteristics of the OD system. The internal recirculation ratio (IRR), namely the ratio of circulation flow rate to influent flow rate in the circular corridor (Insel et al, 2005;Tang and Huang, 2006;Guo et al, 2013;Cakirgöz et al, 2021), is usually mentioned or used to study the influence of internal recirculation characteristics on nutrient removal performance of OD systems. For instance, Insel et al (2005) mentioned that IRR was adjusted to 100, characterizing a high internal flow rate in an OD system.…”

Section: Introductionmentioning

confidence: 99%

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Parameters to characterize the internal recirculation of an oxidation ditch

Wang

2021

WSA

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Mixed liquor circulates ceaselessly in the closed-loop corridor in an oxidation ditch (OD), which is significantly different from other wastewater treatment processes. The internal recirculation ratio (IRR), i.e., the ratio between circulation flow rate (QCC) and influent flow rate (QIn), and the circulatory period (T), i.e. the time consumed for the mixed liquor to complete one lap in the circular corridor, was used to quantify the internal recirculation characteristics of the OD system. In order to elucidate the characteristics and applicability of IRR and T, this study obtained the numerical relationship between IRR and T by formula derivation. It also discusses the factors influencing IRR and analyses the applications of IRR and T. The results showed that IRR = QCC/QIn = HRT/T = HRT IRF (HRT = hydraulic retention time of the mixed liquor in the circular corridor; IRF = internal recirculation frequency). Moreover, three kinds of parameters had an effect on IRR: QIn; reactor dimensions, i.e., length (Lmid), width (B), and height (H) of the circular corridor; and horizontal velocity of the mixed liquor in the circular corridor (v). QIn changed IRR by altering HRT. However, B, H, Lmid, and v changed IRR by altering IRF and T. Furthermore, the same IRR corresponded to many different HRT and IRF. Therefore, when QIn and QCC varied in the OD system, using HRT and IRF to evaluate the variation of QIn and QCC, respectively, was better than using IRR to evaluate their synthetical variation. IRF and T were useful for directly and precisely characterizing the circulation speed and circulation flow rate in the circular corridor, while IRR was more useful for evaluating the dilution effect of reflux on influent.

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Section: Numerical Relationship Between Irr and Tmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parameters to characterize the internal recirculation of an oxidation ditch

Wang

2021

WSA

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“…However, CWs are commonly used to treat domestic wastewater with insu cient C sources (Sun et al 2016;MEEPRC 2020). CWs are also used to treat piggery wastewater and land ll leachate, and the C/N ratio will be as low as 1 (Feng et al 2020;Çakirgöz et al 2021). The discharge of those wastewater with low C/N ratio is still increasing (Mander et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Adding C sources is a common measure to enhance the wastewater treatment performance for wastewater with a low C/N ratio (Chen et al 2020;Çakirgöz et al 2021). Increasing the C/N ratio will enhance N removal (Nguyen et al 2018) and reduce N 2 O emissions (Duan et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Assembling plant diversity mitigates greenhouse gas emissions and achieves high nitrogen removal when treating the low-C/N wastewater by constructed wetlands

Jiang

Han

et al. 2022

Environ Sci Pollut Res

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The low carbon-to-nitrogen (C/N) ratio in wastewater will inhibit pollutant removal, and more seriously, it will cause an increment of nitrous oxide (N 2 O) emissions of constructed wetlands (CWs). Raising the C/N ratio of wastewater is an effective way to solve this problem, while it may cause secondary pollution and is costly. Assembling plant diversity promotes N removal, while the effects of plant diversity and increasing C/N ratio on global warming potential (GWP) combined by N 2 O and methane (CH 4 ) is lack of comparison. In this study, 108 CW microcosms were established to explore the effects of increasing the C/N ratio from 1 to 5 and assembling plant diversity on N removal and GHG emissions. Results showed that when the C/N ratio was 1, (1) increasing species richness reduced N 2 O and CH 4 emissions then reduced the GWP by 70%; (2) the presence of Arundo donax in microcosms reduced GWP by 72%; (3) an A. donax × Tradescantia uminensis × Reineckia carnea mixture resulted in a high N removal and decreased the GWP per g N removal by 92% with a cost increment of 0.05 USD per m 3 wastewater treated; and (4) as the C/N ratio increasing to 5, the GWP per g N removal of monocultures was reduced by 96%, but the cost increased by at least 0.29 USD per m 3 wastewater treated. In summary, con guring plant diversity in CWs is an e cient, clean and cost-effective measure to treat wastewater with a low C/N ratio.

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“…A series of ecological and health risks induced by NO 3 − have attracted wide attention [5]. For instance, high NO 3 − concentration could lead to eutrophication [6], resulting in algal blooms in freshwater or estuaries [7]. High concentrations of NO 3 − and its reduction product, nitrite (NO 2 − ), have been demonstrated to damage the quality and yield of aquaculture species and even to threaten human health via drinking these water sources [8].…”

Section: Introductionmentioning

confidence: 99%

Aerobic Denitrification Is Enhanced Using Biocathode of SMFC in Low-Organic Matter Wastewater

Zhang

Hou

Zhang

et al. 2021

Water

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Nitrate (NO3−) in wastewater is a rising global threat to ecological and health safety. A sufficient carbon source, as the electron donor, is essential in the conventional biological denitrification process. It is not appropriate to add extra carbon sources into specific water bodies in terms of material cost and secondary pollution. Thus, innovative NO3− removal technologies that are independent of carbon sources, are urgently needed. This study constructed sediment microbial fuel cells (SMFCs) for aerobic denitrification in low-organic matter wastewater and explored the key factors affecting denitrification efficiencies. The SMFC treatments removed 72–91% NO3− through two main denitrifying stages which were driven by carbon sources (COD) and generated electrons, respectively. After COD was fully consumed, denitrification efficiencies were enhanced in SMFC treatments by 24–47% using the generated electrons within 3 days. In this stage, the NO3− removal efficiencies were positively correlated with external current intensities (p < 0.05). The improved denitrification efficiencies were attributed to two enriched phyla in the SMFC cathode. The dominant genera also demonstrated the heterotrophic denitrifying capacity of the SMFC biocathode. Furthermore, electrical characteristics could be used to monitor or regulate the denitrification process in the SMFC system. In conclusion, this study presents an innovative treatment strategy that is economical and eco-friendly compared with conventional physicochemical methods.

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How do the influent COD/Nitrogen and internal recirculation ratios affect the oxidation ditch type pre-anoxic landfill leachate treatment?

Cited by 7 publications

References 32 publications

Parameters to characterize the internal recirculation of an oxidation ditch

Parameters to characterize the internal recirculation of an oxidation ditch

Assembling plant diversity mitigates greenhouse gas emissions and achieves high nitrogen removal when treating the low-C/N wastewater by constructed wetlands

Aerobic Denitrification Is Enhanced Using Biocathode of SMFC in Low-Organic Matter Wastewater

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