scholarly journals Phytoremediation of nitrate contaminated water using ornamental plants

2019 ◽  
Vol 68 (8) ◽  
pp. 731-743 ◽  
Author(s):  
S. Shyamala ◽  
N. Arul Manikandan ◽  
Kannan Pakshirajan ◽  
Van Tai Tang ◽  
Eldon R. Rene ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Plant Density ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Ornamental Plants ◽  
Growth Period ◽  
Interaction Effects ◽  
High Plant Density ◽  
Individual Effects ◽  
The Individual

Abstract This work aims at evaluating the potential of two ornamental plant species, i.e., money plant (Epiprennum aureum) and arrowhead plant (Syngonium podophyllum), to treat nitrate containing wastewater. Statistically designed experiments were performed to ascertain the effect of initial nitrate concentration (40–120 mg/L), growth period (1–12 days) and plant density (20–80 g/L) on nitrate removal. Based on the results of analysis of variance (ANOVA), it was observed that the individual effects (F = 78.04 and P = 0.013) of process parameters influenced the nitrate removal efficiency by money plant stronger than the 2-way (F = 0.2 and P = 0.89) and 3-way interaction effects (F = 0.46 and P = 0.569). In the case of the arrowhead plant, the individual effects significantly affected the nitrate removal efficiency than the 2-way and 3-way interaction effects. Low nitrate concentrations (40 mg/L) and high plant density (80 g/L), showed ∼88% nitrate removal by arrowhead plant, during a growth period of 6 d. On the contrary, under similar conditions, the money plant showed a nitrate removal efficiency of ∼93% during a growth period of 12 d. Concerning the removal kinetics, an increase in the growth period increased the nitrate removal rate for both the plants.

scholarly journals Influence of process variables on release properties of paracetamol tablets

2007 ◽  
Vol 57 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Gbenga Alebiowu ◽  
Oludele Itiola
Keyword(s):  
Interaction Effects ◽  
Process Variables ◽  
Factorial Experimental Design ◽  
Disintegration Time ◽  
Individual Effects ◽  
Pregelatinized Starch ◽  
Tablet Formulations ◽  
Binder Concentration ◽  
The Individual ◽  
Paracetamol Tablet

Influence of process variables on release properties of paracetamol tablets A 23 factorial experimental design has been used to quantitatively study individual and interaction effects of the nature of binder (N), binder concentration (c) and relative density of tablet (d) on the disintegration time (DT) and dissolution times, t1, t50 and t90, of paracetamol tablet formulations. The factorial design was also used to study the quantitative effects of pregelatinization of starch binders on these parameters, i.e., N, c and d. In general, the most common ranking of the individual effects on DT, t1, t50 and t90 for native/native, pregelatinized/pregelatinized and native/pregelatinized starch binder formulations was c > d > N. For interaction effects, the most common ranking was N-c > c-d > N-d for all formulations. The results generally showed that c can considerably affect DT, t1, t50 and t90 of the tablets.

scholarly journals Effect of electrode material on removal efficiency regarding single discharges in wire EDM

2021 ◽  
Author(s):  
Lukas Welschof ◽  
Niklas Schäfer ◽  
Tim Herrig ◽  
Andreas Klink ◽  
Thomas Bergs
Keyword(s):  
Removal Efficiency ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Continuous Process ◽  
Wire Edm ◽  
Procedural Understanding ◽  
Decisive Importance ◽  
Effective Removal ◽  
Coated Wires ◽  
The Individual

AbstractFor the precise machining of demanding materials, wire electrical discharge machining (WEDM) is a flexible and often irreplaceable manufacturing process. In order to enhance productivity as the main focus of the wire EDM process, the advancement of the fundamental procedural understanding is of decisive importance. In order to be able to energetically evaluate the removal process, the individual energetic contributors of the process hence the individual discharges need to be understood in terms of their contribution to material removal. In this paper, an experimental setup is presented, which permits the generation of individual discharges on a modern industrial wire EDM machine tool. For three different wire electrodes, the correlation of the discharge energy and the individual removal volume is quantitatively described, showing that coated wires achieve a significantly higher energy-specific removal. Furthermore the removal efficiency is defined as a key figure to transfer the findings to the continuous process and compare theoretical and effective removal rate.

scholarly journals Effects of Ornamental Plant Density and Mineral/Plastic Media on the Removal of Domestic Wastewater Pollutants by Home Wetlands Technology

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5273
Author(s):  
Luis Carlos Sandoval-Herazo ◽  
Alejandro Alvarado-Lassman ◽  
María Cristina López-Méndez ◽  
Albino Martínez-Sibaja ◽  
Alberto A. Aguilar-Lasserre ◽  
...  
Keyword(s):  
Rural Areas ◽  
Plant Density ◽  
Ornamental Plants ◽  
Domestic Wastewater ◽  
High Density ◽  
High Plant Density ◽  
Plant Densities ◽  
Optimal Material ◽  
Planting Distance ◽  
Wastewater Pollutants

Wastewater treatment (WWT) is a priority around the world; conventional treatments are not widely used in rural areas owing to the high operating and maintenance costs. In Mexico, for instance, only 40% of wastewater is treated. One sustainable option for WWT is through the use of constructed wetlands (CWs) technology, which may remove pollutants using cells filled with porous material and vegetation that works as a natural filter. Knowing the optimal material and density of plants used per square meter in CWs would allow improving their WWT effect. In this study, the effect of material media (plastic/mineral) and plant density on the removal of organic/inorganic pollutants was evaluated. Low (three plants), medium (six plants) and high (nine plants) densities were compared in a surface area of 0.3 m2 of ornamental plants (Alpinia purpurata, Canna hybrids and Hedychium coronarium) used in polycultures at the mesocosm level of household wetlands, planted on the two different substrates. Regarding the removal of contaminants, no significant differences were found between substrates (p ≥ 0.05), indicating the use of plastic residues (reusable) is an economical option compared to typical mineral materials. However, differences (p = 0.001) in removal of pollutants were found between different plant densities. For both substrates, the high density planted CWs were able to remove COD in a range of 86–90%, PO4-P 22–33%, NH4-N in 84–90%, NO3-N 25–28% and NO2-N 38–42%. At medium density, removals of 79–81%, 26–32, 80–82%, 24–26%, and 39–41%, were observed, whereas in CWs with low density, the detected removals were 65–68%, 20–26%, 79–80%, 24–26% and 31–40%, respectively. These results revealed that higher COD and ammonia were removed at high plant density than at medium or low densities. Other pollutants were removed similarly in all plant densities (22–42%), indicating the necessity of hybrid CWs to increase the elimination of PO4-P, NO3-N and NO2-N. Moreover, high density favored 10 to 20% more the removal of pollutants than other plant densities. In addition, in cells with high density of plants and smaller planting distance, the development of new plant shoots was limited. Thus, it is suggested that the appropriate distance for this type of polyculture plants should be from 40 to 50 cm in expansion to real-scale systems in order to take advantage of the harvesting of species in these and allow species of greater foliage, favoring its growth and new shoots with the appropriate distance to compensate, in the short time, the removal of nutrients.

Interactive effects of agronomic variables on marketable yield of leeks

1986 ◽  
Vol 106 (3) ◽  
pp. 455-465
Author(s):  
P. J. Salter ◽  
Jayne M. Akehurst ◽  
G. E. L. Morris
Keyword(s):  
Plant Density ◽  
Production Systems ◽  
Nitrogen Nutrition ◽  
Meteorological Data ◽  
Growth Period ◽  
Interactive Effects ◽  
Published Data ◽  
Treatment Combination ◽  
Marketable Yield ◽  
High Plant Density

SummaryTwo experiments were carried out to study the effects of five agronomic variables on the marketable yield of transplanted leeks. In the first experiment two cultivars were used, cvs Splendid and Winterreuzen, and the treatments compared three plantraising systems, two ages of transplant when planted, and two plant population densities, two row spacings and two levels of nitrogen nutrition in the field. In this experiment some treatment interactions were confounded with each other.In the later experiment only cv. Splendid was grown. There were two plant-raising systems, two plant-raising temperatures, two plant-raising nutrition levels, two times of transplanting (63 or 84 days from sowing) and four different sowings (7 and 28 February, 20 March and 10 April 1984). The duration of the growth period in the field was standardized by harvesting each treatment combination on two occasions, 168 and 189 days after transplanting.The results from the first experiment showed that plants raised in modules at high temperature, planted early at a high plant density with higher than normal levels of nitrogen gave high marketable (> 12·5 mm in diameter) yields of 7·31 kg/m2, greater than that from any other treatment combination. The second experiment confirmed these general trends but also showed that the date of transplanting was of critical importance with the earliest plantings in the year giving the highest yields and with later plantings resulting in progressively lower yields irrespective of the way in which the transplants were raised. Comparisons with meteorological data showed that decreasing yields were associated with decreasing values of accumulated solar radiation and accumulated day-degrees during field growth.These results are discussed in relation to other published data. They do not support some of the current recommendations for growing the crop but suggest that much more work needs to be done on production systems for this crop because of the potential for increasing marketable yields.

scholarly journals Growth and Nutrient Removal Efficiency of Sweet Wormwood (Artemisia annua) in a Recirculating Aquaculture System for Nile Tilapia (Oreochromis niloticus)

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 923 ◽  
Author(s):  
Zipporah Gichana ◽  
Paul Meulenbroek ◽  
Erick Ogello ◽  
Silke Drexler ◽  
Werner Zollitsch ◽  
...  
Keyword(s):  
Water Quality ◽  
Removal Efficiency ◽  
Nutrient Removal ◽  
Oreochromis Niloticus ◽  
Plant Density ◽  
Artemisia Annua ◽  
Fish Growth ◽  
Small Scale ◽  
Quality Of Water ◽  
High Plant Density

The maintenance of optimal water quality for fish production is one of the major challenges in aquaculture. Aquaponic systems can improve the quality of water for fish by removing the undesirable wastes and in turn produce a second marketable crop. However, there is no information on the growth and nutrient removal capability of Artemisia annua in aquaponic systems. This study evaluated the effect of plant density on water quality, the growth of A. annua and Oreochromis niloticus in a small scale aquaponic system in Kenya. The aquaponic system consisted of three treatments representing different plant densities (D1: 48 plants/m2, D2: 24 plants/m2 and D3:0 plants/m2). The high plant density system contributed significantly (p < 0.05) to the removal of all nutrients. The removal efficiency of ammonia was significantly higher in D1 (64.1 ± 14.7%) than in D2 (44.5 ± 6.8%) and D3 (38.0 ± 12.1%). Nitrates and nitrites were inconsistent, whereas phosphorus increased gradually in all treatments. The productivity of plants was higher in D1 than D2. Fish growth rates were significantly higher in D1 (0.35 ± 0.03 g/d) and D2 (0.32 ± 0.02 g/d) than in D3 (0.22 ± 0.04 g/d). The results show that A. annua can be cultivated in aquaponic systems due to its nitrogen removal capabilities.

Effects of Molybdenum (VI) on the Denitrification Performance of Activated Sludge Process

2011 ◽  
Vol 183-185 ◽  
pp. 1400-1403
Author(s):  
Xue Zheng Meng ◽  
Xiang Sheng Cao ◽  
Jie Rui Li
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Cod Removal ◽  
Activated Sludge Process ◽  
Inhibitory Effects ◽  
Batch Tests ◽  
Cod Removal Efficiency

The effects of molybdenum (Ⅵ) on the denitrification efficiency of activated sludge process were investigated with batch tests. The results indicated that up to 5 mg/L of Molybdenum (Ⅵ) concentrations in the liquor of activated sludge process could accelerate the nitrate removal rate, exhibiting maximum stimulation at 1 mg/L. Up to 4 mg/L of Molybdenum (Ⅵ) concentrations, the COD removal efficiency was enhanced. Up to 1mg/L of Molybdenum (Ⅵ) concentrations, the TTC-DHA was enhanced but higher concentration showed inhibitory effects. Based on the integrated effects of Molybdenum (Ⅵ) on nitrate and COD removal with the TTC-DHA change, 1mg/L of Molybdenum (Ⅵ) is proposed as the best concentration for denitrification of activated sludge.

Optimal operations for groundwater denitrification of drinking water using heterotrophic biological denitrification process

2006 ◽  
Vol 6 (2) ◽  
pp. 125-130
Author(s):  
C.-H. Hung ◽  
K.-H. Tsai ◽  
Y.-K. Su ◽  
C.-M. Liang ◽  
M.-H. Su ◽  
...  
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Drinking Water Treatment ◽  
Nitrate Content ◽  
Source Water ◽  
Nitrogen Gas ◽  
Negative Effect ◽  
Denitrification Process ◽  
Heterotrophic Denitrification

Due to the extensive application of artificial nitrogen-based fertilizers on land, groundwater from the central part of Taiwan faces problems of increasing concentrations of nitrate, which were measured to be well above 30 mg/L all year round. For meeting the 10 mg/L nitrate standard, optimal operations for a heterotrophic denitrification pilot plant designed for drinking water treatment was investigated. Ethanol and phosphate were added for bacteria growing on anthracite to convert nitrate to nitrogen gas. Results showed that presence of high dissolved oxygen (around 4 mg/L) in the source water did not have a significantly negative effect on nitrogen removal. When operated under a C/N ratio of 1.88, which was recommended in the literature, nitrate removal efficiency was measured to be around 70%, sometimes up to 90%. However, the reactor often underwent severe clogging problems. When operated under C/N ratio of 1.0, denitrification efficiency decreased significantly to 30%. Finally, when operated under C/N ratio of 1.5, the nitrate content of the influent was almost completely reduced at the first one-third part of the bioreactor with an overall removal efficiency of 89–91%. Another advantage for operating with a C/N ratio of 1.5 is that only one-third of the biosolids was produced compared to a C/N value of 1.88.

scholarly journals Optimizing Planting Density and Impact of Panicle Types on Grain Yield and Microclimatic Response Index of Hybrid Rice (Oryza sativa L.)

2021 ◽  
Author(s):  
Guotao Yang ◽  
Xuechun Wang ◽  
Farhan Nabi ◽  
Hongni Wang ◽  
Changkun Zhao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Light Intensity ◽  
Grain Yield ◽  
Hybrid Rice ◽  
Plant Density ◽  
Oryza Sativa L ◽  
Planting Density ◽  
Response Index ◽  
Lower Position ◽  
High Plant Density

AbstractThe architecture of rice plant represents important and complex agronomic traits, such as panicles morphology, which directly influence the microclimate of rice population and consequently grain yield. To enhance yield, modification of plant architecture to create new hybrid cultivars is considered a sustainable approach. The current study includes an investigation of yield and microclimate response index under low to high plant density of two indica hybrid rice R498 (curved panicles) and R499 (erect panicles), from 2017 to 2018. The split-plot design included planting densities of 11.9–36.2 plant/m2. The results showed that compared with R498, R499 produced a higher grain yield of 8.02–8.83 t/ha at a higher planting density of 26.5–36.2 plant/m2. The response index of light intensity and relative humidity to the planting density of R499 was higher than that of R498 at the lower position of the rice population. However, the response index of temperature to the planting density of R499 was higher at the upper position (0.2–1.4%) than at the lower position. Compared with R498, R499 at a high planting density developed lower relative humidity (78–88%) and higher light intensity (9900–15,916 lx) at the lower position of the rice population. Our finding suggests that erect panicles are highly related to grain yield microclimatic contributors under a highly dense rice population, such as light intensity utilization, humidity, and temperature. The application of erect panicle rice type provides a potential strategy for yield improvement by increasing microclimatic conditions in rice.

ALTERNATIVE ROUTES TO INNOVATION — THE EFFECTS OF CULTURAL AND STRUCTURAL FIT

2019 ◽  
Vol 24 (01) ◽  
pp. 2050006
Author(s):  
DAG INGVAR JACOBSEN ◽  
TORE HILLESTAD ◽  
BIRGITTE YTTRI ◽  
JARLE HILDRUM
Keyword(s):  
Response Rate ◽  
Organic Structure ◽  
Configurational Approach ◽  
Culture Strength ◽  
Individual Effects ◽  
Collective Phenomenon ◽  
The Individual ◽  
Alternative Routes ◽  
Innovative Culture ◽  
The Empirical Analysis

A configurational approach to organizations assumes that structural and cultural characteristics must be in “fit” to produce the wanted outcome. With a focus on innovation, this study examines empirically to what extent innovative activities with a large, global telecom company are produced by an innovative culture, an innovative structure, as well as the fit between the two. Based on an extensive survey (N = 21064, response rate = 65) of employees in seven countries in Europe and Asia, data was aggregated to unit level as culture by nature is a collective phenomenon. The empirical analysis detected both the individual effects of culture strength and homogeneity, structure, as well as the fit between the two. The results indicate that an innovative culture and an organic structure indeed fosters innovation, but that, somewhat surprisingly, there are not effects of the fit between the two. Both practical and theoretical implications are discussed.

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