scholarly journals Sediment Remediation for Ecosystem in Eutrophic Lakes

2002 ◽  
Vol 2 ◽  
pp. 885-891 ◽  
Author(s):  
Y. Amano ◽  
K. Taki ◽  
K. Murakami ◽  
T. Ishii ◽  
H. Matsushima
Keyword(s):  
Water Quality ◽  
Green Algae ◽  
Hybrid System ◽  
Size Reduction ◽  
Control Effect ◽  
Sediment Remediation ◽  
Eutrophic Lakes

The remediation method — namely, a hybrid system combined with DAF and CRM — is studied in this paper for the size reduction of aqua-ecological circulation and for the elution control in lakes. Results show that two effects on water quality purification, the sediment washout effect and the elution control effect, can be induced by this system, and the biota inhabiting the lake is therefore shifted into an oligotrophic aspect, from blue algae to green algae and/or diatoms.

The relationship between musty-odor-causing organisms and water quality in Lake Biwa

1995 ◽  
Vol 31 (11) ◽  
pp. 153-158 ◽  
Author(s):  
M. Kajino ◽  
K. Sakamoto
Keyword(s):  
Water Quality ◽  
Data Analysis ◽  
Green Algae ◽  
Analytical Methods ◽  
Lake Biwa ◽  
Blue Green Algae ◽  
Odor Compounds ◽  
Musty Odor ◽  
The Relationship

Musty odor has occurred annually in Lake Biwa since 1969. Osaka municipal waterworks, which is located downstream of Lake Biwa, has made many efforts to treat musty-odor compounds produced in Lake Biwa from spring through autumn. With the development of analytical methods for the determination of musty-odor compounds, we have been able to confirm that planktonic blue-green algae are the major causes of the musty-odor occurrences. The relationship between the growth of blue-green algae and the water quality was not so apparent. However, through our data analysis focusing on the relationship between musty-odor occurrences due to Phormidium tenue or Oscillatoria tenuis and some nutrients in Lake Biwa, we found that the concentration of nitrate in water may be an important parameter for the estimation of growth of the algae and the musty-odor behavior.

Effects of Fe addition on sediment P dynamics in a eutrophic lake

2021 ◽  
Author(s):  
Melanie Münch ◽  
Rianne van Kaam ◽  
Karel As ◽  
Stefan Peiffer ◽  
Gerard ter Heerdt ◽  
...  
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Surface Water ◽  
Water Column ◽  
Sediment Cores ◽  
Surface Water Quality ◽  
Water Interface ◽  
Eutrophic Lakes ◽  
Fe Addition

<p>The decline of surface water quality due to excess phosphorus (P) input is a global problem of increasing urgency. Finding sustainable measures to restore the surface water quality of eutrophic lakes with respect to P, other than by decreasing P inputs, remains a challenge. The addition of iron (Fe) salts has been shown to be effective in removing dissolved phosphate from the water column of eutrophic lakes. However, the resulting changes in biogeochemical processes in sediments as well as the long-term effects of Fe additions on P dynamics in both sediments and the water column are not well understood.</p><p>In this study, we assess the impact of past Fe additions on the sediment P biogeochemistry of Lake Terra Nova, a well-mixed shallow peat lake in the Netherlands. The Fe-treatment in 2010 efficiently reduced P release from the sediments to the surface waters for 6 years. Since then, the internal sediment P source in the lake has been increasing again with a growing trend over the years.</p><p>In 2020, we sampled sediments at three locations in Terra Nova, of which one received two times more Fe during treatment than the other two. Sediment cores from all sites were sectioned under oxygen-free conditions. Both the porewaters and sediments were analysed for their chemical composition, with sequential extractions providing insight into the sediment forms of P and Fe. Additional sediment cores were incubated under oxic and anoxic conditions and the respective fluxes of P and Fe across the sediment water interface were measured.</p><p>The results suggest that Fe and P dynamics in the lake sediments are strongly coupled. We also find that the P dynamics are sensitive to the amount of Fe supplied, even though enhanced burial of P in the sediment was not detected. The results of the sequential extraction procedure for P, which distinguishes P associated with humic acids and Fe oxides, as well as reduced flux of Fe(II) across the sediment water interface in the anoxic incubations, suggest a major role of organic matter in the interaction of Fe and P in these sediments.</p><p>Further research will include investigations of the role of organic matter and sulphur in determining the success of Fe-treatment in sequestering P in lake sediments. Based on these data in combination with reactive transport modelling we aim to constrain conditions for successful lake restoration through Fe addition.</p>

scholarly journals Hyperspectral Data and Machine Learning for Estimating CDOM, Chlorophyll a, Diatoms, Green Algae and Turbidity

2018 ◽  
Vol 15 (9) ◽  
pp. 1881 ◽  
Author(s):  
Sina Keller ◽  
Philipp Maier ◽  
Felix Riese ◽  
Stefan Norra ◽  
Andreas Holbach ◽  
...  
Keyword(s):  
Machine Learning ◽  
Water Quality ◽  
Chlorophyll A ◽  
Green Algae ◽  
Hyperspectral Data ◽  
Coefficient Of Determination ◽  
Inland Waters ◽  
Learning Approaches ◽  
River Elbe ◽  
Regression Framework

Inland waters are of great importance for scientists as well as authorities since they are essential ecosystems and well known for their biodiversity. When monitoring their respective water quality, in situ measurements of water quality parameters are spatially limited, costly and time-consuming. In this paper, we propose a combination of hyperspectral data and machine learning methods to estimate and therefore to monitor different parameters for water quality. In contrast to commonly-applied techniques such as band ratios, this approach is data-driven and does not rely on any domain knowledge. We focus on CDOM, chlorophyll a and turbidity as well as the concentrations of the two algae types, diatoms and green algae. In order to investigate the potential of our proposal, we rely on measured data, which we sampled with three different sensors on the river Elbe in Germany from 24 June–12 July 2017. The measurement setup with two probe sensors and a hyperspectral sensor is described in detail. To estimate the five mentioned variables, we present an appropriate regression framework involving ten machine learning models and two preprocessing methods. This allows the regression performance of each model and variable to be evaluated. The best performing model for each variable results in a coefficient of determination R 2 in the range of 89.9% to 94.6%. That clearly reveals the potential of the machine learning approaches with hyperspectral data. In further investigations, we focus on the generalization of the regression framework to prepare its application to different types of inland waters.

Is water age a reliable indicator for evaluating water quality effectiveness of water diversion projects in eutrophic lakes?

2016 ◽  
Vol 542 ◽  
pp. 281-291 ◽  
Author(s):  
Xiaoling Zhang ◽  
Rui Zou ◽  
Yilin Wang ◽  
Yong Liu ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Diversion ◽  
Reliable Indicator ◽  
Water Age ◽  
Eutrophic Lakes

Multivariable predictive functional control of a compound power-split hybrid electric vehicle

2021 ◽  
pp. 095440702110466
Author(s):  
Ji Gao ◽  
Diming Lou ◽  
Tong Zhang ◽  
Liang Fang ◽  
Yunhua Zhang
Keyword(s):  
Hybrid System ◽  
Hybrid Electric Vehicle ◽  
Control Method ◽  
Multiple Input Multiple Output ◽  
Area Network ◽  
Control Effect ◽  
Decoupling Method ◽  
Input Multiple Output ◽  
Objective Control ◽  
Pure Delay

The Corun hybrid system (CHS) is a deeply coupled multiple-input–multiple-output (MIMO) hybrid system. The two inputs are the torques of the two motors. The two outputs are the carrier speed and transmission output torque. Using the traditional control method, the multi-objective control quality cannot be guaranteed because of the adopted static decoupling method and proportional–integral–derivative (PID) controllers. In this paper, the problems of the traditional control method are carefully analyzed, and a new control method is proposed. Instead of static decoupling, dynamic decoupling is adopted to improve the decoupling control effect. A predictive functional controller instead of a PID controller is adopted to deal with the pure delay caused by controller area network (CAN) communication. The tracking effect of the target value is further improved by predictive functional controllers. For the two decoupled subsystems, that is, the integral system and the second-order underdamped system, two predictive functional controllers are designed. The new control method was verified by simulations and tests. The results show that the new control method is superior to the traditional control method for CHS.

scholarly journals Strategy of Rainwater Discharge in Combined Sewage Intercepting Manhole Based on Water Quality Control

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 898 ◽  
Author(s):  
Zhongqing Wei ◽  
Xiangfeng Huang ◽  
Lijun Lu ◽  
Haidong Shangguan ◽  
Zhong Chen ◽  
...  
Keyword(s):  
Water Quality ◽  
Quality Control ◽  
Control Strategies ◽  
Oxygen Demand ◽  
Water Volume ◽  
Urban Drainage ◽  
Sewage Pollution ◽  
Control Effect ◽  
Poor Control ◽  
Water Quality Control

In view of problems such as the poor control effect of combined sewage pollution caused by traditional intercepting weir and the limited extension of the urban drainage model, which needs a large amount of basic data, this paper not only studied the characteristics of mixed-flow pollution via the urban drainage model but also simulated and optimized 6 interception control strategies and proposed a water quality interception strategy based on the pollution concentration of combined sewage. The results showed that, compared with the traditional interception weir, the interception control strategy of rainwater discharge based on the mixed pipe network model can obviously improve the control rate of various pollutants and reduce the interception amount required for pollution control. Through optimization of the interception based on water quality control by the combination of chemical oxygen demand (COD) and NH4-N, the interception rate was improved by 10.9% to 56.1% in contrast to the traditional interception weir and the closure water volume was reduced by 1432–6154 m3, which effectively improved the reliability and economy of the interception.

scholarly journals Cyanobacterial blooms in shallow lakes of the Iławskie Lake District

2011 ◽  
Vol 11 (2) ◽  
pp. 69-79 ◽  
Author(s):  
Ewa Dembowska
Keyword(s):  
Green Algae ◽  
Trophic Level ◽  
Shallow Lakes ◽  
Algal Blooms ◽  
Catchment Area ◽  
Cyanobacterial Blooms ◽  
Lake District ◽  
Eutrophic Lakes ◽  
Blue Green Algae ◽  
Catchment Areas

Cyanobacterial blooms in shallow lakes of the Iławskie Lake DistrictThe dominance of blue-green algae observed in many lakes is related to a high trophic level. Shallow eutrophic lakes are particularly often abundant in blue-green algae. The research on phytoplankton, the results of which are presented in this paper, was carried out between 2002 and 2005 in six lakes. These lakes differed considerably in their size and management methods applied in the catchment (drainage) area. A few types of water blooms were distinguished, which is related to the catchment area management, the intensity of mixing and the trophic level. Algal blooms of the Planktothrix type appeared in lakes situated in an open area of agricultural catchment basins. Algal blooms of the Limnothrix type were characteristic of lakes with a forest-agricultural catchment area but surrounded by high shores, which reduced the wind influence on the mixing. Sporadic mixed algal blooms were typical of lakes situated in forest catchment areas.

scholarly journals Phytoplankton from Vam Co River in Southern Vietnam

2016 ◽  
Vol 5 (1) ◽  
pp. 113
Author(s):  
Thanh-Son Dao ◽  
Thi-Nhu-Phuong Bui
Keyword(s):  
Water Quality ◽  
Green Algae ◽  
Quality Evaluation ◽  
Nitrate Concentration ◽  
Inorganic Nitrogen ◽  
Environmental Parameters ◽  
Water Quality Assessment ◽  
Species Number ◽  
Dissolved Phosphorus ◽  
Southern Vietnam

<p class="emsd"><span lang="EN-GB">In this study we investigated the variation of phytoplankton and the water quality in Vam Co River, Southern Vietnam. Phytoplankton were bi-monthly monitored in 2011 at 12 sampling sites in the river. Some basic environmental parameters were also monitored including temperature, pH, turbidity, inorganic nitrogen and dissolved phosphorus. The phytoplankton biodiversity and Diatomeae indices were applied for environmental quality evaluation. The results showed that temperature </span><span lang="EN-GB">ranged from 28.7 – 31.9 </span><span lang="EN-GB">°C during the monitoring. The pH and turbidity were in between 3.9 – 7.0 and 2 – 64 NTU, respectively. The nitrate and ammonium concentrations were from 0.06 – 1.21 and 0.03 – 1.15 mg/L, respectively. The phosphate concentration was between 0.02 and 0.37 mg/L. </span><span lang="EN-GB">The environmental parameters were favorable for phytoplankton development. The phytoplankton analyses showed that there were 290 species of diatoms, green algae, golden algae, yellow algae, euglenoids, dinoflagellates and cyanobacteria of which green algae and diatoms were dominant in species number. </span><span lang="EN-GB">Phytoplankton density ranged from 920 – 383 600 individuals/L with the main dominant species of diatoms. The biodiversity index values during the monitoring were from 0.15 – 3.80 characterized for oligotrophic to eutrophic conditions whereas the Diatomeae index values were more than 0.2 indicating for the eutrophic characteristic of the aquatic environment. Besides, phytoplankton species number positively correlated with temperature but negatively correlated with nitrate concentration. Additionally, the biodiversity positively correlated with temperature and species number, but negatively correlated with nitrate and phytoplankton abundance. The results confirmed the advantage of using phytoplankton and their indices for environmental monitoring and water quality assessment.</span></p><p> </p>

Comparison of Chlorophyll a Extractions with Ethanol and Dimethyl Sulfoxide/Acetone, and a Concern about Spectrophotometric Phaeopigment Correction

1992 ◽  
Vol 49 (11) ◽  
pp. 2331-2336 ◽  
Author(s):  
D. J. Webb ◽  
B. K. Burnison ◽  
A. M. Trimbee ◽  
E. E. Prepas
Keyword(s):  
High Pressure ◽  
Dimethyl Sulfoxide ◽  
Chlorophyll A ◽  
Green Algae ◽  
Natural Populations ◽  
Eutrophic Lakes ◽  
North Central ◽  
Chl A ◽  
Blue Green Algae ◽  
Hplc Analyses

Chlorophyll a (Chl a) in water samples from three mesotrophic to eutrophic lakes in north-central Alberta was extracted with one of three solvents (95% ethanol, 90% ethanol, or a 2:3 mixture of dimethyl sulfoxide and 90% acetone (DMSO/acetone)) and analyzed by two techniques (spectrophotometry and high pressure liquid chromatography (HPLC). The dominant phytoplankton were blue-green algae and diatoms. Total Chl a concentrations (i.e. no correction for phaeopigments (Pha)) were not significantly different among solvents (P > 0.5). Total Chl a concentrations from spectrophotometric analyses were significantly higher than those from HPLC analyses (4.2 ± 0.88 and 2.6 ± 0.50 μg∙L−1 respectively, P < 0.05). Pha concentrations derived by spectrophotometry were 64 times higher than those derived by HPLC (1.7 ± 0.52 and 0.025 ± 0.01 μg∙L−1 respectively, P < 0.005). Thus, spectrophotometry appears to dramatically overestimate Pha concentrations and may overestimate total Chl a (i.e. no correction for Pha). Therefore, ethanol and DMSO/acetone are equally suitable for Chl a extraction from natural populations dominated by blue-green algae and/or diatoms, but if information on Pha and/or accessory pigments is required, HPLC analyses are the appropriate route rather than spectrophotometry.

Sedimentary phosphorus speciation dynamics following artificial eutrophication of Lake 227, Experimental Lakes Area, Ontario, Canada

2020 ◽  
Author(s):  
David O'Connell ◽  
Nienke Ansems ◽  
Ravi Kukkadapu ◽  
Deb jaisi ◽  
Diane orihel ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Column ◽  
Humic Substances ◽  
Soluble Phosphate ◽  
Eutrophic Lakes ◽  
Experimental Lakes Area ◽  
Internal P Loading ◽  
P Cycling ◽  
Artificial Fertilization ◽  
Total P

&lt;p&gt;Stringent environmental policies in many countries have played an extensive role in reducing external phosphorus (P) loading to lakes from agriculture and urban sources. Nonetheless, such reductions in external P loading to many eutrophic lakes have not resulted in the expected concurrent restitution of water quality. Such a delayed recovery of many lakes is blamed both on internal loading of legacy P from lake sediments (i.e., benthic recycling) and the amplification of such internal P loading processes due to the reduction in external P concentrations. Hence, a detailed process understanding of P cycling at the sediment-water interface (SWI) is critical to understand nutrient loading, water quality and associated effects on lake water quality. Much of the work on sedimentary P cycling has traditionally focused on inorganic processes of soluble phosphate, particularly sorption to metals (Fe, Mn, Al) oxyhydroxides and clays. However, there is increasing recognition that organic forms of P, along with interactions between phosphate and humic substances, also play a decisive role in controlling P fluxes between sediments and the overlying water column.&lt;/p&gt;&lt;p&gt;This study focused on gaining further understanding of the such processes through the collection of sediment cores from the oxygenated epilimnion and the mostly anoxic hypolimnion of Lake 227 of the Experimental Lakes Area (ELA) in Ontario, Canada. Since 1969, this unique experimental lake has been fertilized with phosphorus (P), which triggered a relatively rapid trophic transition from oligotrophic to eutrophic conditions. The cores contain a chronological record of changes in sediment burial rates and sediment P speciation across this trophic transition.&lt;/p&gt;&lt;p&gt;Interpretation of such changes was undertaken by coupling results of chemical extractions with &lt;sup&gt;210&lt;/sup&gt;Pb sediment dating, &lt;sup&gt;31&lt;/sup&gt;P NMR, XANES and M&amp;#246;ssbauer spectroscopy. The major sedimentary P fraction prior to lake enrichment starting in 1969 was organic P (P&lt;sub&gt;Org&lt;/sub&gt;). Fertilization of the lake in 1969 coincided with significant increases in the accumulation rate of sediment, total organic carbon (TOC) and total P (TP), in addition to a marked relative contribution of NaHCO&lt;sub&gt;3&lt;/sub&gt; extractable P. The combined proportion of P&lt;sub&gt;Hum&lt;/sub&gt; and P&lt;sub&gt;Org&lt;/sub&gt; desposited since artificial fertilization in 1969 account for &amp;#8805;70% of total P burial in the sediments. The anticipated composition of such P&lt;sub&gt;Hum&lt;/sub&gt; fractions was hypothesized to be ternary phosphate (PO&lt;sub&gt;4&lt;/sub&gt;) complexes with humic substances. In support of this, the strong linear correlation between P and iron (Fe) extracted by NaHCO&lt;sub&gt;3&lt;/sub&gt; implies a close association of the two elements in the humic fraction. Furthermore, XANES and M&amp;#246;ssbauer spectra indicate that most Fe in the post-1969 sediments is conserved in the +3 oxidation state, which may be ascribed to the stabilization of reducible Fe by organic matter, partially due to the formation of ternary PO&lt;sub&gt;4&lt;/sub&gt;-Fe(III)-humic complexes. Our findings suggest the artificial eutrophication of Lake 227 resulted in the accelerated accumulation of a large sedimentary reservoir of reactive sediment P that may drive continued internal P loading to the water column following the cessation of artificial fertilization.&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;&lt;/p&gt;

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