Removal Properties of Nitrogen and Phosphorous in Eutrophic Water with Periphyton Attached by Artificial Substrate

2011 ◽  
Vol 340 ◽  
pp. 480-486
Author(s):  
Ding Long Li ◽  
Hong Lu ◽  
Qian Chen ◽  
Jian Ying Chao ◽  
Xiang Ji Kong ◽  
...  
Keyword(s):  
Water Depth ◽  
Water Body ◽  
Removal Rate ◽  
Chemical Properties ◽  
Water Velocity ◽  
New Thought ◽  
Chl A ◽  
Eutrophic Water ◽  
Nitrogen Nutrients ◽  
Depth Water

Removal properties are researched and discussed of algae and nitrogen & phosphorus nutrients with periphyton by assembled substrate in lake-based eutrophic water body, including impacts on removal effects of several physical & chemical properties as water depth, water velocity, DO, temperature and PH. The results show that: the removal rate of NH4-N, other nitrogen nutrients, phosphorus nutrients and Chl-a were 96%, 40%, 80%, 65% respectively. With the growth of water velocity(from 0 to 200L/h ), the removal of Chl-a, TP, TDP increased to a certain extent（Chl-a: from 63.63% to 67.66%; TP:from 76.15% to 85.13%;TDP:from 80.10% to 88.44%）,and that of TN,TDN and NO3-N decreased to different extents（TN: from 45.19% to 31.97%; TDN: from 42.81% to 28.77%; NO3-N: from 38.11% to –5.26%）, but that of NH4-N and PO4-P altered little(NH4-N：from 96.80% to 95.94%；PO4-P：from 85.38% to 87.02%). It will provide reference for recovery and re-contribution of destroyed Eco-system, and a new thought for treatment in eutrophical lakes.

Is it possible to predict habitat use by spawning salmonids? A test using California golden trout (Oncorhynchus mykiss aguabonita)

1999 ◽  
Vol 56 (9) ◽  
pp. 1576-1584 ◽  
Author(s):  
Roland A Knapp ◽  
Haiganoush K Preisler
Keyword(s):  
Oncorhynchus Mykiss ◽  
Water Depth ◽  
Parametric Model ◽  
Water Velocity ◽  
Habitat Characteristics ◽  
Nonparametric Model ◽  
Habitat Features ◽  
Substrate Size ◽  
Depth Water ◽  
Spawning Sites

It is widely believed that stream salmonids select spawning sites based on water depth, water velocity, and substrate size. Attempts to predict spawning locations using these habitat features have met with little success, however. In this study, we used nonparametric logistic regression to determine what habitat features were associated with the locations chosen by spawning California golden trout (Oncorhynchus mykiss aguabonita). From this nonparametric model, we developed a parametric model that incorporated the habitat features most strongly associated with spawning sites and used this model to calculate the probability of use by spawning golden trout for specific stream locations. The overall nonparametric model was highly significant and explained 62% of the variation in spawning location. Four of the eight habitat variables, substrate size, water depth, water velocity, and stream width, had highly significant effects and alone explained 59% of the variation in spawning location. The results of a cross-validation procedure indicated that the parametric model generally provided a good fit to the data. These results indicate that location-specific probabilities of use were predictable based on easily measured habitat characteristics and that nonparametric regression, an approach still rarely used in ecological studies, may have considerable utility in the development of fish-habitat models. Given the escalating pace at which fish habitats are being altered, such models are increasingly important in predicting the effects of these alterations on populations.

scholarly journals Reactive plasma cleaning and restoration of transition metal dichalcogenide monolayers

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniil Marinov ◽  
Jean-François de Marneffe ◽  
Quentin Smets ◽  
Goutham Arutchelvan ◽  
Kristof M. Bal ◽  
...  
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Field Effect Transistors ◽  
Removal Rate ◽  
2D Materials ◽  
Scale Up ◽  
Transition Metal Dichalcogenides ◽  
Chemical Properties ◽  
Plasma Cleaning ◽  
Transition Metal Dichalcogenide

AbstractThe cleaning of two-dimensional (2D) materials is an essential step in the fabrication of future devices, leveraging their unique physical, optical, and chemical properties. Part of these emerging 2D materials are transition metal dichalcogenides (TMDs). So far there is limited understanding of the cleaning of “monolayer” TMD materials. In this study, we report on the use of downstream H2 plasma to clean the surface of monolayer WS2 grown by MOCVD. We demonstrate that high-temperature processing is essential, allowing to maximize the removal rate of polymers and to mitigate damage caused to the WS2 in the form of sulfur vacancies. We show that low temperature in situ carbonyl sulfide (OCS) soak is an efficient way to resulfurize the material, besides high-temperature H2S annealing. The cleaning processes and mechanisms elucidated in this work are tested on back-gated field-effect transistors, confirming that transport properties of WS2 devices can be maintained by the combination of H2 plasma cleaning and OCS restoration. The low-damage plasma cleaning based on H2 and OCS is very reproducible, fast (completed in a few minutes) and uses a 300 mm industrial plasma etch system qualified for standard semiconductor pilot production. This process is, therefore, expected to enable the industrial scale-up of 2D-based devices, co-integrated with silicon technology.

Analyzing of UVLC system considering the effect of water depth

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mustafa B. Al-Deen ◽  
Mazin Ali A. Ali ◽  
Zeyad A. Saleh
Keyword(s):  
Coastal Water ◽  
Water Depth ◽  
Bit Error Rate ◽  
Multiple Input Multiple Output ◽  
Visible Light Communications ◽  
New Approach ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Depth Water

Abstract This paper presents a new approach to discover the effect of depth water for underwater visible light communications (UVLC). The quality of the optical link was investigated with varying water depth under coastal water types. The performance of the UVLC with multiple input–multiple output (MIMO) techniques was examined in terms of bit error rate (BER) and data rate. The theoretical result explains that there is a good performance for UVLC system under coastal water.

scholarly journals Optimization of Responses MRR and HC in EDM of Al/4.6B4C super alloy using GA

2020 ◽  
Vol 6 (5) ◽  
pp. 1-5
Keyword(s):  
Material Removal ◽  
Removal Rate ◽  
Chemical Properties ◽  
Micro Hardness ◽  
Electric Discharge Machining ◽  
Process Output ◽  
Physical And Chemical ◽  
Aluminium Metal ◽  
Super Alloy ◽  
And Chemical Properties

Aluminium metal matrix super alloy belongs to advanced category of super alloy which finds wide place in numerous important industry such as aerospace, automobile, missiles etc. because of its elevated mechanical, physical and chemical properties. The innovative manufacturing processes have come into existence to machine such kinds of newer super alloys. Electric discharge machining (EDM) is such a process which is comprehensively applied these days for machining of AMMCs. In the present research the EDM experimentation on Al/4.6B4C composites by considering discharge current, Ton and Toff as process performances have been conducted. The material removal rate and micro hardness have been considered as process output parameters. The RSMs has been developed for both the responses and finally single objective optimization of both the response parameters have been done by applying RSM- genetic algorithm-based optimization (GA) approach. It has been observed that GA gives better results.

scholarly journals Phytoplankton Community Investigation and Water Quality Assessment of M River in winter in Shijiazhuang City

2021 ◽  
Vol 267 ◽  
pp. 01035
Author(s):  
Ziqi Zhang ◽  
Lei Yang ◽  
Dongxu Han ◽  
Hongyan Shen
Keyword(s):  
Water Quality ◽  
Species Diversity ◽  
Water Body ◽  
Phytoplankton Community ◽  
Diversity Index ◽  
Water Quality Assessment ◽  
Species Diversity Index ◽  
Wiener Diversity Index ◽  
Eutrophic Water ◽  
Evenness Index

An investigation of phytoplankton community and water quality for M River was conducted in December 2019.The results showed that 38 species of phytoplankton belonging to 6 phyla and 26 genera were collected. Among them, Bacillariophyta is the richest species, which accounted for 34.21%, followed by Cyanophyta with 26.32% and Chlorophyta with 28.95%. The density of phytoplankton was 63.0*106 inds/L which indicated as eutrophic water body. The highest density was Bacillariophyta, accounting for 51.03%. The Shannon-Wiener diversity index (H’) varied from 1.34 to 2.24, the Margalef Species diversity index (d) varied from 2.71 to 3.85, and the Pielou evenness index (J) varied from 0.38 to 0.67. According to the integrative analysis results of H’, d and J, M River water quality belongs to oligo-polluted, but individual sites belong to meso-polluted.

scholarly journals Abundance of macrozoobenthos in relation to bottom soil textural types and water depth In aquaculture ponds

2014 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
N Nupur ◽  
M Shahjahan ◽  
MS Rahman ◽  
MK Fatema
Keyword(s):  
Water Depth ◽  
Sandy Loam ◽  
Chemical Properties ◽  
Experimental Period ◽  
Quality Parameters ◽  
Population Densities ◽  
Bottom Soil ◽  
Aquaculture Ponds ◽  
Different Depths ◽  
The Mean

The present experiment was conducted to evaluate the effects of bottom soil textural classes and different water depths on abundance of macrozoobenthos in aquaculture ponds. Three treatments, i.e., ponds bottom with sandy loam (T1), with loam (TS2) and with clay loam (T3) were considered in this experiment. Samples were collected from three different depths (60.96 cm, 106.68 cm and 152.40 cm) with three replications. The ranges of water quality parameters were suitable for the growth of macrozoobenthos during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed comparatively higher ranges in T2. Eight genera were recorded belonging to major groups of Chironomidae, Oligochaeta, Mollusca and Ceratoponogonidae. The highest population densities of Oligochaeta (1200±4.25 per m2), Chironomidae (1422±4.88 per m2), Ceratopogonidae (399±1.56 per m2) and Mollusca (977±2.24 per m2) were found in T2. The population densities of macrozoobenthos showed fortnightly variations in all the treatments. Among the three depths, significantly highest densities of macrozoobenthos were recorded in 106.68 cm in every treatment. The mean abundance of macrozoobenthos was significantly highest in T2. The present study indicates that loamy soil pond bottom along with water depth 106.68 cm is suitable for the growth and production of macrozoobenthos in aquaculture ponds. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17811 Int. J. Agril. Res. Innov. & Tech. 3 (2): 1-6, December, 2013

Effects of operation parameters on nutrient removal from wastewater and high-protein biomass production in a duckweed-based (Lemma aequinoctialis) pilot-scale system

2014 ◽  
Vol 70 (7) ◽  
pp. 1195-1204 ◽  
Author(s):  
Yonggui Zhao ◽  
Yang Fang ◽  
Yanling Jin ◽  
Jun Huang ◽  
Shu Bao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Biomass Production ◽  
Water Depth ◽  
Nutrient Removal ◽  
Removal Rate ◽  
Pilot Scale ◽  
Coverage Rate ◽  
High Protein ◽  
Dianchi Lake ◽  
Operation Conditions

The effects of water depth, coverage rate and harvest regime on nutrient removal from wastewater and high-protein biomass production were assessed in a duckweed-based (Lemna aequinoctialis) pilot-scale wastewater treatment system (10 basins × 12 m2) that is located near Dianchi Lake in China. The results indicated that a water depth of 50 cm, a coverage rate of 150% and a harvest regime of 4 days were preferable conditions, under which excellent records of high-protein duckweed (dry matter production of 6.65 g/m2/d with crude protein content of 36.16% and phosphorus content of 1.46%) were obtained at a temperature of 12–21 °C. At the same time, the system achieved a removal efficiency of 66.16, 23.1, 48.3 and 76.52% for NH4+-N, TN, TP and turbidity, respectively, with the considerable removal rate of 0.465 g/m2/d for TN and 0.134 g/m2/d for TP at a hydraulic retention time of 6 days. In additionally, it was found that a lower duckweed density could lead to higher dissolved oxygen in the water and then a higher removal percentage of NH4+-N by nitrobacteria. This study obtains the preferable operation conditions for wastewater treatment and high-protein biomass production in a duckweed-based pilot-scale system, supplying an important reference for further large-scale applications of duckweed.

scholarly journals Water quality in Lake Xochimilco, Mexico: zooplankton indicators and Vibrio cholerae

2015 ◽  
Author(s):  
Sarma Nandini ◽  
Pedro Ramirez García ◽  
S.S.S. Sarma
Keyword(s):  
Water Quality ◽  
Vibrio Cholerae ◽  
Chlorophyll A ◽  
Local Population ◽  
Secchi Depth ◽  
Treatment Plant ◽  
Nitrogen And Phosphorus ◽  
Physico Chemical ◽  
Eutrophic Water ◽  
Depth Water

<p>Lake Xochimilco is a eutrophic water body in Mexico City used by the local population for aquaculture and agriculture. Water level is maintained with inputs of partially treated waste water from the Cerro de la Estrella treatment plant. In this study we analysed the water quality at two sites of Lake Xochimilco, Lake Xaltocan and the Santa Cruz Canal using various indicators such as zooplankton diversity, saprobic indices, bacterial concentrations and physico-chemical variables. Eighty litres of water was filtered from Lake Xochimilco from each site, once a month from March to October of 2012, and the rotifers, cladocerans and copepods were enumerated and identified. Physico-chemical parameters such as temperature, pH, Secchi depth, water depth, nitrogen and phosphorus and chlorophyll a concentrations, and bacterial densities were measured. During the study we recorded 33 species of rotifers, the most abundant being <em>Brachionus angularis</em>, <em>B. calyciflorus</em> and <em>B. havanaensis</em>.  Among the microcrustaceans the most abundant were the cladoceran <em>Moina micrura</em> and the copepods <em>Acanthocyclops americanus</em> and <em>Arctodiaptomus dorsalis</em>. The species diversity was around 2 bits/ind. and the saprobic index between 1.5-2.0, indicating that both sites were β meso-saprobic.  At both sites nitrogen was &lt;1 mg/L and phosphorus ranged between 2.5-7.8 mg/L. Chlorophyll a concentrations were between 66-136 µg/L. The toxigenic (<em>Vibrio cholerae </em>No-O1/No-O139) and the non-toxigenic (<em>Vibrio cholerae </em>No-O135) strains of the bacterium were recorded, closely associated with littoral rotifers and cladocerans particularly <em>Brachionus quadridentatus</em> and  <em>Alona</em> sp. All variables indicate that these sites in Lake Xochimilco are eutrophic and highly contaminated and that the water quality needs to be improved.<strong></strong></p>

scholarly journals Limnology of Lake Bogakain, Bandarban, Bangladesh

1970 ◽  
Vol 39 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Moniruzzaman Khondker ◽  
Md Almujaddade Alfasane ◽  
Md Shafiqul Islam ◽  
M Azmal Hossain Bhuiyan ◽  
Md Ataul Gani
Keyword(s):  
Water Temperature ◽  
Negative Correlation ◽  
Phytoplankton Biomass ◽  
Thermal Spring ◽  
Turbid Water ◽  
Depth Gradient ◽  
Chl A ◽  
Different Depths ◽  
First Time ◽  
Depth Water

Bogakain, a natural high altitude (372 m) lake of Bangladesh has been limnologically investigated for the first time. At mid-point, the depth of the lake was measured 46.54 m and the Secchi visibility was 2.37 m. Water temperature from 1-10 m depth gradient showed slight stratification in the lake which varied from 27.0 - 22.4° C at 1.00 pm. pH at the different depths ranged from 7.8 - 9.1, conductivity from 75 - 80 μS/cm and TDS from 39 - 42 mg/l. Alkalinity ranged from 0.8 - 1.24 meq/l and DO from 0.61 - 11.39 mg/l. A total of 40 species of phytoplank-ton were recorded from the lake of which 21 belonged to Chlorophyceae followed by Cynaophyceae (5), Bacillariophyceae (4), Cryptophyceae (4), Euglenophyceae (3), Dinophyceae (2) and Chrysophyceae (1). Bloom by Synnechocystis salina Wisl was observed at 10 m depth. Water temperature correlated negatively and significantly with depth. Phytoplankton biomass as chl a correlated positively with phytoplankton density and water depth. The former variable showed negative correlation with pH and water temperature. Lake Bogakain is the deepest natural lake of Bangladesh and many of the previous concepts regarding the lake i.e., fishless, highly turbid water and it has got a thermal spring at the bottom was found invalid. Key words: Bogakain; Limnology; Macrophyte; Phytoplankton; Bangladesh DOI: 10.3329/bjb.v39i2.7301 Bangladesh J. Bot. 39(2): 153-159, 2010 (December)  

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