scholarly journals Enhance nitrogen removal in bioretention cells with addition of hydrothermal pre-treated pine barks as external carbon source

2021 ◽  
Author(s):  
Jing Tuo ◽  
Shiwei Cao ◽  
Muzi Li ◽  
Rong Guo
Keyword(s):  
Carbon Source ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Common Factor ◽  
Nutrients Removal ◽  
Fiber Structure ◽  
Effluent Quality ◽  
External Carbon Source ◽  
Carbon Release ◽  
Cod Removal Rate

Abstract The problem of poor carbon source is a common factor limiting the nutrients removal in bioretention cells (BRCs). This study aimed to investigate the feasibility of using modified biomass in BRCs filled with a mixture of fly ash ceramsite and pumice fillers to enhance nitrogen removal. Different pretreatment methods (hydrothermal-treated, acid-treated and alkali-treated) were attempted, and hydrothermal pretreatment showed a best performance in carbon release ability. The scanning electron microscopy showed that the lignin in hydrothermal pretreated pine barks (H-PBs) was destroyed, and the fiber structure became thinner with more irregular folds, which improved the accessibility of cellulose and attachment of microorganisms. The addition of H-PBs significantly enhanced the nutrients removal in BRCs, and the removal rates of TN and NO3−-N increased by 23.25% and 38.22% compared with those in BRC-A (without external carbon source), but the removal rate of NH4+-N was inferior to BRC-A. Besides, the large carbon release amount of H-PBs did not deteriorate the effluent quality, with COD removal rate of 87.98% in the 48 d. These results indicate that the BRCs by adding H-PBs could intensify the denitrification process.

Enhancing denitrification efficiency for nitrogen removal using waste sludge alkaline fermentation liquid as external carbon source

2018 ◽  
Vol 26 (5) ◽  
pp. 4633-4644 ◽  
Author(s):  
Mengyu Shao ◽  
Liang Guo ◽  
Zonglian She ◽  
Mengchun Gao ◽  
Yangguo Zhao ◽  
...  
Keyword(s):  
Carbon Source ◽  
Nitrogen Removal ◽  
Waste Sludge ◽  
External Carbon Source ◽  
Fermentation Liquid

scholarly journals Study of COD Removal Rate on a Sequencing Batch Reactor (SBR) Treating Tapioca Wastewater

2019 ◽  
Vol 38 (3) ◽  
pp. 243
Author(s):  
Happy Mulyani ◽  
Gregorius Prima Indra Budianto ◽  
Margono Margono ◽  
Mujtahid Kaavessina
Keyword(s):  
Wastewater Treatment ◽  
Sequencing Batch Reactor ◽  
Removal Rate ◽  
Batch Reactor ◽  
Cod Removal ◽  
Operation Condition ◽  
Effluent Quality ◽  
Aeration Time ◽  
Standard Quality ◽  
Cod Removal Rate

Industrial wastewater treatment using Sequencing Batch Reactor (SBR) can improve effluent quality at lower cost than that obtained by other biological treatment methods. Further optimization is still required to enhance effluent quality until it meets standard quality and to reduce the operating cost of treatment of high strength organic wastewater. The purpose of this research was to determine the effect of pretreatment (pH adjustment and prechlorination) and aeration time on effluent quality and COD removal rate in tapioca wastewater treatment using SBR. Pretreatment was done by (1) adjustment of tapioca wastewater pH to control (4.92), 7, and 8, and (2) tapioca wastewater prechlorination at pH 8 during hour using calcium hypochlorite in variation dosages 0, 2, 4, 6 mg/L Cl2, SBR operation was conducted according to following steps: (1) Filling of pre-treated wastewater into a bioreactor during 1 hour, and (2) aeration of the mixture of tapioca wastewater and activated sludge during 8 hours. Effluent sample was collected at every 2-hours aeration for COD analysis. COD removal rate mathematical formula was got by first deriving the best fit function between aeration time and COD. Optimum aeration time resulting in no COD removal rate. The value of COD effluent and its removal rate in optimum aeration time was used to determine the recommended of operation condition of pretreatment. Research result shows that chosen pH operation condition is pH 8. Prechorination can make effluent quality which meets standard quality and highest COD removal rate. The chosen Cl2 dosage is 6 mg/L.

scholarly journals Methane Emissions Driven by Adding a Gradient of Ethanol as Carbon Source in Integrated Vertical-Flow Constructed Wetlands

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1086
Author(s):  
Xiaoling Liu ◽  
Jingting Wang ◽  
Xiaoying Fu ◽  
Hongbing Luo ◽  
Bruce C. Anderson ◽  
...  
Keyword(s):  
Carbon Source ◽  
Constructed Wetlands ◽  
Control Experiment ◽  
Ethanol Concentration ◽  
Removal Rate ◽  
Carbon Sources ◽  
Vertical Flow ◽  
Emission Flux ◽  
Rate Range ◽  
External Carbon Source

This work aims to investigate the methane emissions from integrated vertical-flow constructed wetlands (IVCWs) when ethanol is added as an external carbon source. In this study, a gradient of ethanol (0, 2, 4, 8, 16 and 32 mmol/L) was added as the carbon source in an IVCW planted with Cyperus alternifolius L. The results showed that the methane emission flux at an ethanol concentration of 32 mmol/L was 32.34 g CH4 m−2 day−1 less than that of the control experiment (0 mmol/L) and that the methane emission flux at an ethanol concentration of 16 mmol/L was 5.53 g CH4 m−2 day−1 less than that at 0 mmol/L. In addition, variations in the water quality driven by the different ethanol concentrations were found, with a redox potential range of −64 mV to +30 mV, a pH range of 6.6–6.9, a chemical oxygen demand (COD) removal rate range of 41% to 78%, and an ammonia nitrogen removal rate range of 59% to 82% after the ethanol addition. With the average CH4-C/TOC (%) value of 35% driven by ethanol, it will be beneficial to understand that CH4-C/TOC can be considered an ecological indicator of anthropogenic methanogenesis from treatment wetlands when driven by carbon sources or carbon loading. It can be concluded that adding ethanol as an external carbon source can not only meet the water quality demand of the IVCW treatment system but also stimulate and increase the average CH4 emissions from IVCWs by 23% compared with the control experiment. This finding indicates that an external carbon source can stimulate more CH4 emissions from IVCWs and shows the importance of carbon sources during sewage treatment processes when considering greenhouse emissions from treated wetlands.

An Experimental Study on Compatible Solute Ectoine Dosing of High Salinity Wastewater

2014 ◽  
Vol 955-959 ◽  
pp. 1907-1910
Author(s):  
Su Chen ◽  
Lei Chao ◽  
Ning Chen ◽  
Lin Shan Wang ◽  
Xue Shao ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Waste Treatment ◽  
High Salinity ◽  
Removal Rate ◽  
Ammonia Nitrogen ◽  
Ammonium Nitrogen ◽  
Treatment Efficiency ◽  
Removal Rates ◽  
Cod Removal Rate ◽  
Salinity Wastewater

When the reactor is added with ectoine of concentrations of 0, 0.1, 1 and 10 mmol/L, the impacts on brine waste treatment efficiency are investigated. The results show that the outflow COD and ammonia nitrogen removal rates are the highest, when the ectoine concentration is 0.1 mmol/L. The brine waste treatment efficiency under addition of ectoine of 1 and 10 mmol/L is even worse than that without ectoine addition. It can be preliminarily determined that the best ectoine dosage is in between 0.1-1.0 mmol/L. When ectoine concentrations added in reactors are 0.2, 0.5, 0.8 and 1.0 mmol/L, the results show that the average reactor outflow COD and ammonia nitrogen removal rates are increased compared with those of reactor without adding ectoine. But when ectoine of 1.0 mmol/L is added, the outflow COD and ammonia nitrogen removal rates decrease. When ectoine dosage is 0.5 mmol/L, the reactor outflow COD and ammonia nitrogen values are the lowest, the removal rates are the highest, the average COD removal rate is 74.46%, and the average ammonium nitrogen removal rate is 54.97%. Compared with reactor without adding ectoine, COD and ammonium nitrogen removal rates are increased by 13.16% and 26.81%. Therefore, the best dosage of ectoine is 0.5 mmol/L.

Biological Filters for Post-Denitrification

1993 ◽  
Vol 27 (5-6) ◽  
pp. 369-379 ◽  
Author(s):  
Svend-Erik Jepsen ◽  
Jes la Cour Jansen
Keyword(s):  
Carbon Source ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Head Loss ◽  
Slow Increase ◽  
Loading Rates ◽  
Carrier Material ◽  
External Carbon Source ◽  
Removal Capacity ◽  
Biological Filters

Nitrifying wastewater treatment plants exist in many European countries. These plants can be extended for Total-Nitrogen removal by a post-denitrification stage using an external carbon source. A compact solution for this process is submerged biological filters. Two pilot plants have been used as post-denitrification reactors, a down-flow filter with expanded slate as carrier material (Biocarbone) and an up-flow filter with polystyrene pellets as carrier material (Biostyr). Nitrified wastewater was treated to a stable effluent quality from both pilot plants to below the Danish effluent standard which is 8 mg Tot-N/l. The pilot plants have been operated at different loading rates with acetate as external carbon source. Stable removal with effluent nitrate less than 5 mg NO3-N/l was obtained for loading rates up to more than 4 kg NO3-N/m3 d at 10-17°C. The removal capacity of the pilot plants has been shown to be independent of time from last backwash. The removal rate over different sections of the filters does not change within one operation cycle. The backwash removes the excess biomass and particles which cause the head loss, but the removal capacity remains in the filter. The head loss development in the two systems is quite different. In the Biostyr system, the head loss raises close to linear with time (load), while the Biocarbone shows slow increase in head loss with time until the surface is clogged by incoming particles and biomass growth. When this occurs, the nitrogen bubbles, which are produced in the lower part of the filter, are trapped just below the top layer. The void volume of the filter is occupied by nitrogen gas and the head loss increases very fast to the terminal head loss. This investigation has shown that both kinds of submerged filters are capable to serve as post-denitrification reactors to remove nitrate to the most stringent effluent standards.

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