Nitrate removal from aquaculture effluents using woodchip bioreactors improved by adding sulfur granules and crushed seashells

2018 ◽  
Vol 77 (9) ◽  
pp. 2301-2310 ◽  
Author(s):  
Mathis von Ahnen ◽  
Per Bovbjerg Pedersen ◽  
Johanne Dalsgaard
Keyword(s):  
Removal Rate ◽  
Nitrate Removal ◽  
Response Surfaces ◽  
Reactor Performance ◽  
Total N ◽  
Mixture Ratio ◽  
Aquaculture Effluents ◽  
N Removal ◽  
Sulfur Granules ◽  
Central Composite

Abstract This study examined the effects on nitrate removal when adding sulfur granules and crushed seashells to a woodchip bioreactor treating aquaculture effluents. Using a central composite design, the two components were added at three levels (0.000, 0.125 and 0.250 m3/m3 bioreactor volume) to 13 laboratory-scale woodchip bioreactors, and a response surface method was applied to find and model the optimal mixture ratios with respect to reactor performance. Adding 0.125 m3/m3 sulfur granules improved the total N removal rate from 3.27 ± 0.38 to 8.12 ± 0.49 g N/m3/d compared to pure woodchips. Furthermore, the inclusion of crushed seashells together with sulfur granules helped to maintain the pH above 7.4 and prevent a production (i.e., release) of nitrite. According to the modeled response surfaces, a sulfur granule:crushed seashell:woodchip mixture ratio containing about 0.2 m3 sulfur granules and 0.1 m3 crushed seashells per m3 reactor volume would give the best results with respect to high N removal and minimal nitrite release. In conclusion, the study showed that N removal in woodchip bioreactors may be improved by adding sulfur granules and seashells, contributing to the optimization of woodchip performance in treating aquaculture effluents.

Performance of intermittent aeration reactor on NH4-N removal from groundwater resources

2010 ◽  
Vol 61 (12) ◽  
pp. 3061-3069 ◽  
Author(s):  
W. Khanitchaidecha ◽  
T. Nakamura ◽  
T. Sumino ◽  
F. Kazama
Keyword(s):  
Removal Rate ◽  
Groundwater Resources ◽  
Ammonium Nitrogen ◽  
Total Carbon ◽  
Intermittent Aeration ◽  
Reactor Performance ◽  
Total Carbon Content ◽  
Term Operation ◽  
N Removal ◽  
Synthetic Groundwater

To study the effect of intermittent aeration period on ammonium–nitrogen (NH4-N) removal from groundwater resources, synthetic groundwater was prepared and three reactors were operated under different conditions – “reactor A” under continuous aeration, “reactor B” under 6 h intermittent aeration, and “reactor C” under 2 h intermittent aeration. To facilitate denitrification simultaneously with nitrification, “acetate” was added as an external carbon source with step-wise increase from 0.5 to 1.5 C/N ratio, where C stands for total carbon content in the system, and N for NH4-N concentration in the synthetic groundwater. Results show that complete NH4-N removal was obtained in “reactor B” and “reactor C” at 1.3 and 1.5 C/N ratio respectively; and partial NH4-N removal in “reactor A”. These results suggest that intermittent aeration at longer interval could enhance the reactor performance on NH4-N removal in terms of efficiency and low external carbon requirement. Because of consumption of internal carbon by the process, less amount of external carbon is required. Further increase in carbon in a form of acetate (1.5 to 2.5 C/N ratios) increases removal rate (represented by reaction rate coefficient (k) of kinetic equation) as well as occurrence of free cells. It suggests that the operating condition at reactor B with 1.3 C/N ratio is more appropriate for long-term operation at a pilot-scale.

scholarly journals Nitrogen removal from ammonium-contaminated groundwater using dropping nitrification–cotton-based denitrification reactor

2021 ◽  
Author(s):  
A. K. Maharjan ◽  
K. Mori ◽  
K. Nishida ◽  
T. Toyama
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Denitrifying Bacteria ◽  
Electron Donors ◽  
Nitrifying Bacteria ◽  
Contaminated Groundwater ◽  
Total N ◽  
N Removal ◽  
Denitrification Reactor ◽  
Synthetic Groundwater

Abstract A novel dropping nitrification–cotton-based denitrification reactor was developed for total nitrogen (N) removal from ammonium (NH4+)-contaminated groundwater. The nitrogen removal ability of the reactor was evaluated for 91 days. A 1 m-long dropping nitrification unit was fed with synthetic groundwater containing 30 mg-NH4+-N/L at a flow rate of 2.16 L/d. The outlet of the dropping nitrification unit was connected to the cotton-based denitrification unit. The NH4+ present in the groundwater was completely oxidized (>90% nitrification efficiency) by nitrifying bacteria to nitrite (NO2–) and nitrate (NO3–) in the dropping nitrification unit. Subsequently, the generated NO2– and NO3– were denitrified (96%–98% denitrification efficiency) by denitrifying bacteria in the cotton-based denitrification unit under anoxic conditions. Organic carbons released from the cotton presumably acted as electron donors for heterotrophic denitrification. Nitrifying and denitrifying bacteria were colonized in higher abundance in the dropping nitrification and cotton-based denitrification units, respectively. The total N removal rate and efficiency of the dropping nitrification–cotton-based denitrification reactor for 91 days were 58.1–66.9 mg-N/d and 96%–98%, respectively. Therefore, the dropping nitrification–cotton-based denitrification reactor will be an efficient, sustainable, and promising option for total N removal from NH4+-contaminated groundwater.

scholarly journals Design and operation of submerged layer in bioretention for enhanced nitrate removal

2019 ◽  
Vol 68 (8) ◽  
pp. 744-756 ◽  
Author(s):  
Junyu Zhang ◽  
Rajendra Prasad Singh ◽  
Yunzhe Liu ◽  
Dafang Fu
Keyword(s):  
Activated Carbon ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Yangtze River Delta ◽  
Lake Basin ◽  
Modified Activated Carbon ◽  
N Removal ◽  
Tai Lake ◽  
N 93 ◽  
Tai Lake Basin

Abstract Bioretention, initially designed for treating discontinuous runoff pollution, faces considerable challenges in its trade-off between the hydraulic retention time (HRT) and its treatment capacity. In this study, six enhanced submerged media together with four HRTs were designed for bioretention cells to treat the highly nitrogenous river water in Tai lake basin in Yangtze River delta, China. Results revealed that bioretention with activated carbon has the highest removal of nitrate (NO3−-N) (93–96%) compared with surfactant-modified activated carbon (SMAC), surfactant-modified zeolite (SMZ), zeolite, fly ash and ceramsite. Although the SMAC had the best absorption for NO3−-N and could desorb NO3−-N when its concentration was low in the submerged layer, the desorbed surfactant could inhibit the growth of denitrifying bacteria, which leads to low removal efficiency (49–66%). The dynamic balancing of NO3−-N desorption and denitrifying system restrain in the SMAC device was observed and explained. The best activated carbon-gravel proportion in the submerged layer was 1:1 (150 mm). Such design could ensure the stable and efficient NO3−-N removal rate (93–94%) under high inflow concentration (28.9 mg/L) and high hydraulic loading (8.2 cm/h).

Impact of Nitrogen Management Practices on Total Nitrogen in the Fruits of High Productive Hamlin Orange Trees

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498e-498
Author(s):  
S. Paramasivam ◽  
A.K. Alva
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Fine Sand ◽  
Fruit Production ◽  
Perennial Crop ◽  
Total N ◽  
N Removal ◽  
Leaf N Concentration ◽  
N Rates ◽  
Orange Trees

For perennial crop production conditions, major portion of nutrient removal from the soil-tree system is that in harvested fruits. Nitrogen in the fruits was calculated for 22-year-old `Hamlin' orange (Citrus sinensis) trees on Cleopatra mandarin (Citrus reticulata) rootstock, grown in a Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) that received various N rates (112, 168, 224, and 280 kg N/ha per year) as either i) broadcast of dry granular form (DGF; four applications/year), or ii) fertigation (FRT; 15 applications/year). Total N in the fruits (mean across 4 years) varied from 82 to 110 and 89 to 111 kg N/ha per year for the DGF and FRT sources, respectively. Proportion of N in the fruits in relation to N applied decreased from 74% to 39% for the DGF and from 80% to 40% for the FRT treatments. High percentage of N removal in the fruits in relation to total N applied at low N rates indicate that trees may be depleting the tree reserve for maintaining fruit production. This was evident, to some extent, by the low leaf N concentration at the low N treatments. Furthermore, canopy density was also lower in the low N trees compared to those that received higher N rates.

Agricultural practices and diffuse nitrogen pollution in Denmark: empirical leaching and catchment models

1999 ◽  
Vol 39 (12) ◽  
pp. 257-264 ◽  
Author(s):  
Hans E. Andersen ◽  
Brian Kronvang ◽  
Søren E. Larsen
Keyword(s):  
Agricultural Land ◽  
Root Zone ◽  
Agricultural Practices ◽  
Animal Manure ◽  
Annual Runoff ◽  
N Leaching ◽  
N Loss ◽  
Total N ◽  
Model Calculations ◽  
N Removal

An empirical leaching model was applied to data on agricultural practices at the field level within 6 small Danish agricultural catchments in order to document any changes in nitrogen (N) leaching from the root zone during the period 1989-96. The model calculations performed at normal climate revealed an average reduction in N-leaching that amounted to 30% in the loamy catchments and 9% in the sandy catchments. The reductions in N leaching could be ascribed to several improvements in agricultural practices during the study period: (i) regulations on livestock density; (ii) regulations on the utilisation of animal manure; (iii) regulations concerning application practices for manure. The average annual total N-loss from agricultural areas to surface water constituted only 54% of the annual average N leached from the root zone in the three loamy catchments and 17% in the three sandy catchments. Thus, subsurface N-removal processes are capable of removing large amounts of N leached from agricultural land. An empirical model for the annual diffuse N-loss to streams from small catchments is presented. The model predicts annual N-loss as a function of the average annual use of mineral fertiliser and manure in the catchment and the total annual runoff from the unsaturated zone.

scholarly journals An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3390
Author(s):  
Hui Zhang ◽  
Lin Song ◽  
Xiaolin Chen ◽  
Pengcheng Li
Keyword(s):  
Growth Rate ◽  
Bacillus Subtilis ◽  
Nitrate Removal ◽  
Denitrifying Bacteria ◽  
Soil Salinization ◽  
Nitrate Content ◽  
Weak Efficiency ◽  
N Accumulation ◽  
N Removal ◽  
Intensively Managed

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.

Influence of C/N Ratio on SND and Microbiological Analysis in Catching Bed Biofilm Reactor Using Acrylic Resin Fiber as Carrier Materials in Civil Engineering

2012 ◽  
Vol 568 ◽  
pp. 89-93
Author(s):  
Yan Zhang ◽  
Zheng Yang Yang ◽  
Li Li Wang ◽  
Xu Ying Zhao ◽  
Huan Guang Liu ◽  
...  
Keyword(s):  
Civil Engineering ◽  
Removal Rate ◽  
Acrylic Resin ◽  
Biofilm Reactor ◽  
Easy Access ◽  
Fish Analysis ◽  
Microbiological Analysis ◽  
Ammonia Oxidizing Bacteria ◽  
N Removal ◽  
Carrier Materials

In this study, effect of C/N ratio on denitrification were investigated using four sets of parallel catching bed reactors, which were using acrylic resin fiber (ARF) as carrier materials. The results indicate that this process which was used in wastewater treatment of civil engineering can get better COD and nitrogen removing performance. NH4+-N removal rate reduced with the increasing of C/N ratio, and the average removal rate of COD and the total nitrogen (TN) increased when C/N ratio is increased. When C/N ratio exceeded 12, TN removal rate has no obvious growing. Meanwhile, fluorescent in situ hybridization (FISH) analysis indicated that the biomass in the biofilm were much richer than which in the suspension, and the ammonia oxidizing bacteria have a easy access to be dominant bacterial community in lower C/N ratio.

Machinability Evaluation in the Ultrasonic Drilling (USD) Process of Aluminum Oxide-based Ceramics

2011 ◽  
Vol 223 ◽  
pp. 804-812
Author(s):  
R. S. Jadoun
Keyword(s):  
Aluminum Oxide ◽  
Mathematical Models ◽  
Removal Rate ◽  
Ceramic Materials ◽  
Performance Characteristics ◽  
Machining Parameters ◽  
Ultrasonic Drilling ◽  
The Face ◽  
Face Centered ◽  
Central Composite

The ultrasonic drilling (USD) has been used in the manufacture of the hard, fragile, difficult to cut, nonconductive ceramic materials. In this study, the mathematical models of material removal rate (MRR) and surface roughness (SR) have been obtained for the machinability evaluation in the USD process of aluminum oxide-based ceramic material. The experimental plan adopts the face centered central composite design (CCD). The mathematical models using the response surface methodology (RSM) are developed so as to investigate the influences of three machining parameters, including the power rating, grit size and slurry concentration on the performance characteristics of MRR and SR. It has been proved that the proposed mathematical models in this study would fit and predict values of the performance characteristics, which would be close to the readings recorded in experiment with a 95% confidence level. The significant parameters that critically affect the performance characteristics are examined.

scholarly journals In Situ Water Quality Improvement Mechanism (Nitrogen Removal) by Water-Lifting Aerators in a Drinking Water Reservoir

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1051 ◽  
Author(s):  
Zizhen Zhou ◽  
Tinglin Huang ◽  
Weijin Gong ◽  
Yang Li ◽  
Yue Liu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Nitrogen Removal ◽  
High Throughput Sequencing ◽  
Removal Rate ◽  
Water Reservoir ◽  
Control Area ◽  
Nitrite Accumulation ◽  
Field Scale ◽  
Drinking Water Reservoir ◽  
N Removal

A field scale experiment was performed to explore the nitrogen removal performance of the water and surface sediment in a deep canyon-shaped drinking water reservoir by operating WLAs (water-lifting aerators). Nitrogen removal performance was achieved by increasing the densities and N-removal genes (nirK and nirS) of indigenous aerobic denitrifiers. After the operation of WLAs, the total nitrogen removal rate reached 29.1 ± 0.8% in the enhanced area. Ammonia and nitrate concentrations were reduced by 72.5 ± 2.5% and 40.5 ± 2.1%, respectively. No nitrite accumulation was observed. Biolog results showed improvement of carbon metabolism and carbon source utilization of microbes in the enhanced area. Miseq high-throughput sequencing indicated that the denitrifying bacteria percentage was also higher in the enhanced area than that in the control area. Microbial communities had changed between the enhanced and control areas. Thus, nitrogen removal through enhanced indigenous aerobic denitrifiers by the operation of WLAs was feasible and successful at the field scale.

scholarly journals Nitrogen-metabolising Microorganism Analysis in Rapid Sand Filters From Drinking Water Treatment Plant by Culturing and Metagenomics

2021 ◽  
Author(s):  
Qihui Gu ◽  
Jun Ma ◽  
Jumei Zhang ◽  
Weipeng Guo ◽  
Huiqing Wu ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Removal Rate ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Amplicon Sequencing ◽  
Metabolic Model ◽  
Rrna Gene ◽  
N Removal

Abstract Sand filter (SFs) are common treatment processes for nitrogen pollutants removal in drinking water treatment plants (DWTPs). However, the mechanisms on the nitrogen-cycling role of SFs are still unclear. In this study, 16S rRNA gene amplicon sequencing was used to characterise the diversity and composition of the bacterial community in SFs from DWTPs. Additionally, metagenomics approach was used to determine the functional microorganisms involved in nitrogen cycle in SFs. Our results showed that Proteobacteria, Acidobacteria, Nitrospirae, and Chloroflexi dominated in SFs. Subsequently, 85 high-quality metagenome-assembled genomes (MAGs) were retrieved from metagenome datasets of selected SFs involving nitrification, assimilatory nitrogen reduction, and denitrification processes. Read mapping to reference genomes of Nitrospira and the phylogenetic tree of the ammonia monooxygenase subunit A gene, amoA, suggested that Nitrospira is abundantly found in SFs. Furthermore, according to their genetic content, a nitrogen metabolic model in SFs was proposed using representative MAGs and pure culture isolates. Quantitative real-time polymerase chain reaction (PCR) showed that ammonia-oxidising bacteria (AOB) and archaea (AOA), and complete ammonia oxidisers (comammox) were ubiquitous in the SFs, with the abundance of comammox being higher than that of AOA and AOB. Moreover, we identified a bacterial strain with a high NO3-N removal rate as Pseudomonas sp., which could be applied in the bioremediation of micro-polluted drinking water sources. Our study provides insights into functional nitrogen-metabolising microbes in SFs of DWTPs.

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