Effects of age class on N removal capacity of oysters and implications for bioremediation

2015 ◽  
Vol 528 ◽  
pp. 205-220 ◽  
Author(s):  
DJ Dalrymple ◽  
RH Carmichael
Keyword(s):  
Age Class ◽  
Removal Capacity ◽  
N Removal

scholarly journals Spatial Pattern of Dissolved Nitrogen in the Water on Receiving Agricultural Drainage in the Sanhuanpao Wetland in China

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2683
Author(s):  
Xiaodong Wang ◽  
Lijuan Chu ◽  
Yujia Song ◽  
Guodong Wang ◽  
Ming Jiang
Keyword(s):  
Spatial Pattern ◽  
Nitrogen Removal ◽  
Water Channel ◽  
Ammonia Nitrogen ◽  
Agricultural Drainage ◽  
Dissolved Nitrogen ◽  
Removal Capacity ◽  
N Removal ◽  
The Difference ◽  
The Relationship

The total nitrogen (TN) increases and the water quality deteriorates when a large amount of nitrogen-containing water is discharged from farmlands into wetlands. This research on the relationship between the TN, ammonia nitrogen (NH4-N), and nitrate nitrogen (NO3-N) concentrations in water has a certain reference significance for understanding the spatial pattern of nitrogen removal in wetlands. Taking the Sanhuanpao wetland in northeast China as the research object, 24 sampling plots in the study area were sampled in the spring and summer of 2017 to test the concentrations of TN, NH4-N, and NO3-N. Based on the calculations of the change rates of the TN, NH4-N, and NO3-N in spring and summer, a step-by-step elimination analysis was carried out and the spatial pattern of the TN, NH4-N, and NO3-N removals were revealed by gradual buffer extrapolations, combined with stepwise fitting functions. The results show that the removal capacity of NH4-N is strong within the range of 14.55 km–20 km and 26.93 km–35.96 km from the wetland inlet, and the removal capacity of NO3-N is relatively strong within the range of 26.93 km–35.96 km. The strong NH4-N and NO3-N removal areas in the wetland are not in the geometric center of the wetland, but in separate narrow areas around the center. The TN removal along water channel direction is only 0.25 times higher than that direction perpendicular to the channel, indicating that regardless of whether wetlands are expanded along the water channel or perpendicular to the water channel, the difference to the TN removal is small. Effectively monitoring and managing the reception of agricultural drainage is extremely important for maintaining the water-purification function of wetlands. The aim of the research is to reveal a spatial law of nitrogen removal in wetland water, and provide a framework for studying the mechanism of spatial difference of nitrogen.

scholarly journals Zeolite as a Potential Medium for Ammonium Recovery and Second Cheese Whey Treatment

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 136 ◽  
Author(s):  
Aggelos Kotoulas ◽  
Dimitra Agathou ◽  
Irene Triantaphyllidou ◽  
Triantafyllos Tatoulis ◽  
Christos Akratos ◽  
...  
Keyword(s):  
Natural Zeolite ◽  
Cheese Whey ◽  
Freundlich Isotherm ◽  
Operating Mode ◽  
Column Experiments ◽  
Removal Capacity ◽  
N Removal ◽  
Slow Release Fertilizers ◽  
Nitrogen Nutrients ◽  
Adsorption Rates

The efficiency of natural zeolite to remove ammonium from artificial wastewater (ammonium aqueous solutions) and to treat second cheese whey was examined, aiming to recover nitrogen nutrients that can be used for further applications, such as slow-release fertilizers. Sorption experiments were performed using artificial wastewater and zeolite of different granulometries (i.e., 0.71–1.0, 1.8–2.0, 2.0–2.8, 2.8–4.0, and 4.0–5.0 mm). The granulometry of the zeolite had no significant effect on its ability to absorb ammonium. Nevertheless, smaller particles (0.71–1.0 mm) exhibited quicker NH4+-N adsorption rates of up to 93.0% in the first 10 min. Maximum ammonium removal efficiency by the zeolite was achieved at ammonium concentrations ranging from 10 to 80 mg/L. Kinetic experiments revealed that chemisorption is the mechanism behind the adsorption process of ammonium on zeolite, while the Freundlich isotherm model fitted the experimental data well. Column sorption experiments under batch operating mode were performed using artificial wastewater and second cheese whey. Column experiments with artificial wastewater showed high NH4+-N removal rates (over 96% in the first 120 min) for all granulometries and initial NH4+-N concentrations tested (200 and 5000 mg/L). Column experiments with second cheese whey revealed that natural zeolite can remove significant organic loads (up to 40%, 14.53 mg COD/g of zeolite) and NH4+-N (about 99%). For PO43−-P, the zeolite appeared to saturate after day 1 of the experiments at a removal capacity of 0.15 mg P/g of zeolite. Desorption experiments with water resulted in low NH4+-N and PO43−-P desorption rates indicating that the zeolite could be used as a substrate for slow nitrogen release in soils.

scholarly journals The potential of seaweed cultivation to achieve carbon neutrality and mitigate deoxygenation and eutrophication

2021 ◽  
Author(s):  
Guang Gao ◽  
Lin Gao ◽  
Meijia Jiang ◽  
Ao Jian ◽  
Linwen He
Keyword(s):  
Organic Carbon ◽  
Saccharina Japonica ◽  
Gracilariopsis Lemaneiformis ◽  
Seaweed Cultivation ◽  
Carbon Neutrality ◽  
Removal Capacity ◽  
N Removal ◽  
Oceanic Sediments

Abstract Carbon neutrality has been proposed due to the increasing concerns about the consequences of rising atmospheric CO2. Previous studies overlooked the role of lost particle organic carbon (POC) and excreted dissolved organic carbon (DOC) from seaweed cultivation in carbon sequestration, that is to say, long term carbon storage in the oceanic sediments and in the water. This study assessed the potential of seaweed cultivation to achieve carbon neutrality of China by 2060 using a new method that included lost POC and excreted DOC. Based on the seaweed production in the years 2015-2019 in China, harvested seaweed removed 605,193 tonnes of carbon, 70,304 tonnes of nitrogen and 8,619 tonnes of phosphorus from seawaters annually; farmed seaweed sequestrated 343,766 tonnes of carbon and generated 2530,558 tonnes of oxygen annually. Among the seven farmed seaweeds, Gracilariopsis lemaneiformis has the highest capacities for carbon removal (9.58 tonnes ha-1 yr-1) and sequestration (5.44 tonnes ha-1 yr-1) and thus has the smallest cultivation area required to sequestrate 2.5 Gt CO2 that is annually required to achieve China's carbon neutrality goal by 2060. The O2 generated by seaweed cultivation could increase dissolved oxygen in seawaters (0-3 m deep) by 21% daily, which could effectively counteract deoxygenation in seawaters. Gracilariopsis lemaneiformis also has the highest N removal capacity while Saccharina japonica has the highest P removal capacity. To completely absorb the N and P released from the fish mariculture, a production level or a cultivation area two and three times larger (assuming productivity remains unchanged) would be required. This study indicates that seaweed cultivation could play an important role in achieving carbon neutrality and mitigating deoxygenation and eutrophication in seawaters. Cultivation cost could be offset to some extent by increased sales of the harvest parts of the seaweed for food and biofuel.

Removal of Nitrogen and Phosphorus from Black-Odor Water by Different Submerged Plants

2020 ◽  
Vol 14 (4) ◽  
pp. 524-530
Author(s):  
Guoning Chen ◽  
Liushu Pan ◽  
Zhuo Sun ◽  
Jianhua Xiong ◽  
Hongxiang Zhu ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Mixed Culture ◽  
Total Biomass ◽  
Submerged Plants ◽  
Nitrogen And Phosphorus ◽  
Removal Capacity ◽  
N Removal ◽  
Eutrophic Water ◽  
Control Scheme ◽  
Sustainable Wastewater Treatment

In general, nitrogen and phosphorus in eutrophic water are absorbed by submerged plants for growth, which is considered as a feature and frequently applied in sustainable wastewater treatment. These plants are entirely submerged at the bottom of the water, absorbing nitrogen and phosphorus by roots, stems, leaves and epidermal cells. Compared with other species of aquatic plants, submerged plants show certain advantages in the aspects of planting area, total biomass and total removal of nitrogen and phosphorus. Rational utilization of submerged plants is an effective way to remove nitrogen and phosphorus from eutrophic water. Submerged macrophyte has been at the focus of attention in recent years as an alternative system for aquatic plant wastewater treatment with several applications in eutrophication. Aiming at the pollution control scheme of inland lakes, in this study, the removal of nitrogen and phosphorus by Hydrilla verticillaya (H. verticillaya) and Vallisneria natans (V. natans) were studied and compared in monoculture and mixed-culture plantings, thus screened the best submerged plants. Results showed that the removal capacity for ammonium (NH+4–N), Nitrate (NO–3–N) and total phosphorus (TP) from high to low was NH+4–N, NO–3–N, and TP. Reasonable allocation of plants can improve the removal efficiency of nitrogen and phosphorus. The order of removal capacity for different submerged plants to pollutants was: mixed culture V. natans and H. verticillaya > H. verticillaya > V. natans. The transformation of NO–3–N to NH+4–N was considered as the NH+4–N removal mechanism.

scholarly journals Nutrient removal capacity of wood residues for the Agro-environmental safety of ground and surface waters

2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Paulo A. Dumont ◽  
David. R. Chadwick ◽  
Steve Robinson
Keyword(s):  
Municipal Wastewater ◽  
Industrial Effluents ◽  
Environmental Safety ◽  
Exchange Capacity ◽  
Removal Capacity ◽  
N Removal ◽  
Wood Residues ◽  
Wide Range ◽  
And Performance ◽  
Desorption Capacity

Abstract   The aim of this study was to determine the effectiveness of wood residues in the removal of nutrients (ammonium-N; NH4-N) from nutrient-rich (NH4-N) waters. The water holding capacity of the wood materials was also determined. Carried out at Rothamsted Research, North Wyke, UK, this controlled laboratory experiment tested two wood residues; in length, one being 1-2cm and the other from 150 µm (microns) to 9.5mm. Although a wide range of studies have shown the effectiveness and performance of various absorbent materials as animal beddings, such as straw (cereal straw), woodchip (sawdust, bark or wood shavings), bracken and rushes, only few have focused on the NH4-N sorption/desorption capacity. The depuration capacity of wood residues from nutrient-rich effluents such as those from cattle bedded on woodchip or straw will be controlled by processes such as sorption (adsorption-absorption) and desorption of nutrients. Studies have reported the nitrogen removal capacity of woodchip materials and biochar from woodchip as well as removal of NH4+-N from domestic and municipal wastewater, farm dirty water, landfill and industry effluents. These studies have observed that the mechanism of removal of nitrogen is by either increasing NO3--N removal form leachate by enhancing N2O losses via denitrification (biochar as carbon source for denitrifiers) or by decreasing NH4+-N in leachate through adsorption to negatively charged sites. Results showed that although the cation exchange capacity (CEC) and surface area (SA) are both fundamental properties of adsorbent materials, no correlation was found with CEC and adsorption or desorption. Nor did changes in pH appear to be sufficiently important to cause changes in CEC. For this reason, osmotic pressure appeared to be a more predominant parameter controlling processes of adsorption and desorption of NH4+-N in both wood residues. Thus, wood residues high in NH4+-N should be avoided, as they could have an opposite effect in the adsorption of nutrients from nutrient-rich effluents. The results also showed that some wood residues (G30) had great capacity to adsorb NH4+-N to levels up to nearly 90% whilst demonstrating low desorption capacity of NH4+-N (less than 1%). These are ideal relevant features for an adsorbent material for the removal of nutrients (or heavy metals) from contaminated waters such us farm o industrial effluents, or for the depuration of eutrophic watercourses. This could help reduce the concentration of farm effluents making them more manageable, subsequently contributing towards the compliance of new environmental regulations. Keywords: nutrients, nitrogen, ground and surface water

DYE REMOVAL CAPACITY OF GRAPHENE OXIDE-IRON NANO PARTICLE COMPOSITE AS AN ADSORBENT

2018 ◽  
Author(s):  
Jyoti N. Thakre Sanjay R. Thakre P.T.Kosankar Kavita Gour Jyoti N. Thakre Sanjay R. Thakre P.T.Kosankar Kavita Gour ◽  
Keyword(s):  
Graphene Oxide ◽  
Dye Removal ◽  
Nano Particle ◽  
Particle Composite ◽  
Removal Capacity

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.

The Use of Anoxic Selectors for the Control of Low F/M Activated Sludge Bulking

1989 ◽  
Vol 21 (6-7) ◽  
pp. 609-619 ◽  
Author(s):  
Y.-J. Shao ◽  
David Jenkins
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Pilot Plant ◽  
Detention Time ◽  
Substrate Removal ◽  
Batch System ◽  
Sludge Bulking ◽  
N Removal ◽  
Soluble Substrate ◽  
Activated Sludge Systems

Laboratory and pilot plant experiments on anoxic selector activated sludge systems were conducted on two wastewaters in some cases supplemented with nitrate, acetate or glucose. To prevent bulking sufficient anoxic selector detention time and nitrate levels must be available to reduce selector effluent soluble COD to below 100 mg/l and to reduce readily metabolizable organic matter to virtually zero (< 1 mg/l). Soluble COD/NO3-N removal stoichiometry is in the range 6.0-6.7. Selector systems have elevated soluble substrate removal and denitrification rates compared to CSTR systems. These rates are not affected greatly by temperature (20-25°C) for CSTR sludges but are for selector sludges. Upon exhaustion of nitrate in a selector soluble COD leaks out of the activated sludge in significant amounts. Thiothrix sp. and type 021N denitrify only to NO2 and at much slower rates than Zoogloearamigera does to N2. A sequencing batch system provides an optimistic estimate of the SVI that can be obtained by an anoxic selector system.

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