Enhancement of nitrate removal under limited organic carbon by coupled with hydrogen‐driven autotrophic denitrification in low‐cost electrodes bio‐electrochemical reactors

A major limitation to building credible soil carbon sequestration programs is the cost of measuring soil carbon change. Diffuse reflectance spectroscopy (DRS) is considered a viable low-cost alternative to traditional laboratory analysis of soil organic carbon (SOC). While numerous studies have shown that DRS can produce accurate and precise estimates of SOC across landscapes, whether DRS can detect subtle management induced changes in SOC at a given site has not been resolved. Here, we leverage archived soil samples from seven long-term research trials in the U.S. to test this question using mid infrared (MIR) spectroscopy coupled with the USDA-NRCS Kellogg Soil Survey Laboratory MIR spectral library. Overall, MIR-based estimates of SOC%, with samples scanned on a secondary instrument, were excellent with the root mean square error ranging from 0.10 to 0.33% across the seven sites. In all but two instances, the same statistically significant (p < 0.10) management effect was found using both the lab-based SOC% and MIR estimated SOC% data. Despite some additional uncertainty, primarily in the form of bias, these results suggest that large existing MIR spectral libraries can be operationalized in other laboratories for successful carbon monitoring.

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Treatment of Combined Acid Black 48 and Coffee Wastewater by Low-Cost Adsorbents

Environmental Research Engineering and Management ◽

10.5755/j01.erem.76.3.25338 ◽

2020 ◽

Vol 76 (3) ◽

pp. 47-61

Author(s):

Yung-Tse Hung ◽

Abhiram Pamula ◽

Howard Paul

Keyword(s):

Activated Carbon ◽

Organic Carbon ◽

Binary Mixture ◽

Surface Waters ◽

Low Cost ◽

Combined Treatment ◽

Synthetic Dyes ◽

Treatment Methods ◽

Onion Peel ◽

Peanut Hull

Removal of synthetic dyes from wastewater is essential both from the environmental and human health point of view. A small concentration of synthetic dyes can reduce water transparency and consequently influence photosynthesis and alter aquatic ecosystems. Acid black 48 is an Azo dye that falls under the category of synthetic dyes used in the textile industry. With dyes, coffee wastewater has high chemical oxygen demand (COD) that can affect dissolved oxygen (DO) in surface waters. A mixture of wastes in surface waters creates a need to investigate the efficiency of existing treatment methods and optimize them. Adsorption using activated carbon is a conventional method used to remove dyes and heavy metals from wastewater. Industries prefer efficient and economical treatment methods to meet challenging effluent standards regarding COD, BOD, and intensity of color. The adsorption process was optimized using low-cost adsorbents in the current study, including peanut hull and onion peel, to treat a binary mixture of acid black 48 and coffee wastewater. After adsorption, microfiltration was used to remove any suspended solids from the wastewater solution. The performance of combined treatment processes for the color removal of the binary mixture was analyzed and compared using transmittance and absorbance. Treatment efficiency of adsorption using low-cost adsorbents was compared with powdered activated carbon. Apart from absorbance and transmittance, non-purgeable organic carbon (NPOC) values were analyzed to determine organic carbon removal in the combined binary wastewater. Experimental results indicated that Langmuir isotherm was the best fit for a binary mixture with an optimum dosage of 1.2 g using onion peel. The regression coefficient value was 0.82, and the uptake was 58.13 mg of binary mixture per 1 g of onion peel. The effective pH for maximum uptake of acid black 48 using onion peel for adsorption was 5.7. The increasing dosage of low-cost adsorbents adsorption improved in removing binary waste of dyes and coffee waste from wastewater. Adsorption using onion peel improved adsorbent performance up to 1.2 g dosage and steadily decreased beyond that. The adsorption capacity of onion peel was comparatively higher than the peanut hull based on the linear fit.

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Nitrate Removal with Sulfur-Limestone Autotrophic Denitrification Processes

Journal of Environmental Engineering ◽

10.1061/(asce)0733-9372(1999)125:8(721) ◽

1999 ◽

Vol 125 (8) ◽

pp. 721-729 ◽

Cited By ~ 64

Author(s):

Joel M. Flere ◽

Tian C. Zhang

Keyword(s):

Nitrate Removal ◽

Autotrophic Denitrification

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Coupled Sulfur and Iron(II) Carbonate-Driven Autotrophic Denitrification for Significantly Enhanced Nitrate Removal

Environmental Science & Technology ◽

10.1021/acs.est.8b06865 ◽

2018 ◽

Vol 53 (3) ◽

pp. 1545-1554 ◽

Cited By ~ 18

Author(s):

Ting-ting Zhu ◽

Hao-yi Cheng ◽

Li-hui Yang ◽

Shi-gang Su ◽

Hong-cheng Wang ◽

...

Keyword(s):

Nitrate Removal ◽

Autotrophic Denitrification

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Predicting Soil Organic Carbon and Total Nitrogen at the Farm Scale Using Quantitative Color Sensor Measurements

Agronomy ◽

10.3390/agronomy8100212 ◽

2018 ◽

Vol 8 (10) ◽

pp. 212 ◽

Cited By ~ 4

Author(s):

Roxanne Stiglitz ◽

Elena Mikhailova ◽

Julia Sharp ◽

Christopher Post ◽

Mark Schlautman ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Total Nitrogen ◽

Low Cost ◽

Rapid Assessment ◽

Soil Health ◽

Sensor Technology ◽

P Value ◽

Color Sensor ◽

Farm Scale

Sensor technology can be a reliable and inexpensive means of gathering soils data for soil health assessment at the farm scale. This study demonstrates the use of color system readings from the Nix ProTM color sensor (Nix Sensor Ltd., Hamilton, ON, Canada) to predict soil organic carbon (SOC) as well as total nitrogen (TN) in variable, glacial till soils at the 147 ha Cornell University Willsboro Research Farm, located in Upstate New York, USA. Regression analysis was conducted using the natural log of SOC (lnSOC) and the natural log of TN (lnTN) as dependent variables, and sample depth and color data were used as predictors for 155 air dried soil samples. Analysis was conducted for combined samples, Alfisols, and Entisols as separate sample sets and separate models were developed using depth and color variables, and color variables only. Depth and L* were significant predictors of lnSOC and lnTN for all sample sets. The color variable b* was not a significant predictor of lnSOC for any soil sample set, but it was for lnTN for all sample sets. The lnSOC prediction model for Alfisols, which included depth, had the highest R2 value (0.81, p-value < 0.001). The lnSOC model for Entisols, which contained only color variables, had the lowest R2 (0.62, p-value < 0.001). The results suggest that the Nix ProTM color sensor is an effective tool for the rapid assessment of SOC and TN content for these soils. With the accuracy and low cost of this sensor technology, it will be possible to greatly increase the spatial and temporal density of SOC and TN estimates, which is critical for soil management.

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Simultaneous arsenite and nitrate removal from simulated groundwater based on pyrrhotite autotrophic denitrification

Water Research ◽

10.1016/j.watres.2020.116662 ◽

2021 ◽

Vol 189 ◽

pp. 116662

Author(s):

Ruihua Li ◽

Mengsha Guan ◽

Wei Wang

Keyword(s):

Nitrate Removal ◽

Autotrophic Denitrification ◽

Simulated Groundwater

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Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Water ◽

10.3390/w12020516 ◽

2020 ◽

Vol 12 (2) ◽

pp. 516 ◽

Cited By ~ 2

Author(s):

Rauno Lust ◽

Jaak Nerut ◽

Kuno Kasak ◽

Ülo Mander

Keyword(s):

Organic Carbon ◽

Dissolved Oxygen ◽

Oxygen Concentration ◽

Power Efficiency ◽

Municipal Wastewater ◽

Nitrate Removal ◽

Treatment Plant ◽

Municipal Wastewater Treatment ◽

Dissolved Oxygen Concentration ◽

Organic Carbon Concentration

Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.

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