scholarly journals Nickel effects on productivity of algal periphyton communities

2015 ◽  
Vol 50 (4) ◽  
pp. 369-374
Author(s):  
Hamid Reza Ghassemi
Keyword(s):  
Chlorophyll A ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Dry Mass ◽  
Biological Properties ◽  
Nickel Concentration ◽  
Artificial Streams ◽  
Chemical Factors ◽  
Physical And Chemical

In order to evaluate the long-term (30-day) influence of nickel on biomass of periphyton communities, indoor artificial streams were used with differing nickel concentration (2.5, 5, and 7.5 mg/l). Physical and chemical factors (pH, NO3-N, PO4-P, dissolved oxygen, total suspended solids, conductivity, total dissolved solids, biochemical oxygen demand, and chemical oxygen demand) were measured along with biological properties of the periphyton. The effects of nickel on periphyton communities were assessed by measuring dry mass, ash-free dry mass (AFDM), chlorophyll-a, and rate of nickel absorption. In artificial streams with nickel, there was a significant (P < 0.05) reduction of chlorophyll-a, AFDM, and dry mass under the influence of nickel. These observations suggest that the periphyton community could serve as an indicator of nickel pollution.

scholarly journals Fluctuations of the population of Daphnia laevis Birge 1878: a six-year study in a tropical lake

2012 ◽  
Vol 72 (3) ◽  
pp. 479-487 ◽  
Author(s):  
LPM. Brandão ◽  
T. Fajardo ◽  
E. Eskinazi-Sant'Anna ◽  
S. Brito ◽  
P. Maia-Barbosa
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Trophic State ◽  
Trophic Status ◽  
Seasonal Pattern ◽  
Ecological Research ◽  
Total Phosphorous ◽  
Long Term Ecological Research ◽  
Physical And Chemical

The fluctuation of the population of Daphnia laevis in Lake Jacaré (Middle River Doce, Minas Gerais) was monitored monthly (at one point in the limnetic region) for six years (2002-2007) as part of the Program of Long-Term Ecological Research (LTER/UFMG). The following parameters were also monitored: water temperature, pH, electrical conductivity, dissolved oxygen, chlorophyll a, total phosphorus, phosphate, total nitrogen, nitrate, nitrite, ammonia, and densities of Chaoborus and ephippia of Daphnia laevis in the sediment. A seasonal pattern was observed in the fluctuation of D. laevis, with higher densities recorded during periods of circulation (May-August). A significant correlation was found between the density of D. laevis and temperature (r = -0.47, p = 0.0001), chlorophyll-a (r = -0.32, p = 0.016) and indicators of the lake's trophic status (total phosphorus, r = 0.32, p = 0.007 and trophic state, r = 0.36, p = 0.003), as well as Chaoborus density (r = 0.43 and p = 0.002). These results indicate that changes in the physical and chemical characteristics of the water related with stratification and circulation of the lake may have a direct (temperature, total phosphorous) or an indirect (food availability, presence of predators, ephippia eclosion) influence on the fluctuation of the D. laevis population.

Study of the effect of some physical and chemical factors on the biological properties and chemıcal composition of viper venom

2020 ◽  
Vol 12 (1) ◽  
pp. 29-36
Author(s):  
H. A. Abiyev ◽  
E. S. Jafarov ◽  
Sh. A. Sh. A. Topchiyeva ◽  
H. G. Babayev ◽  
Kh. R. Mammadova
Keyword(s):  
Chemical Composition ◽  
Biological Properties ◽  
Chemical Factors ◽  
Physical And Chemical

scholarly journals The Evaluation of a Risk Degree for the Process of a Brown Coal Spontaneous Ignition on Dumps with Using of Modern Numeric Methods

2018 ◽  
Vol 26 (2) ◽  
pp. 71-75
Author(s):  
Petr Klouda ◽  
Vlastimil Moni ◽  
Michal Řehoř ◽  
Jan Blata ◽  
František Helebrant
Keyword(s):  
Brown Coal ◽  
Barometric Pressure ◽  
Spontaneous Ignition ◽  
Atmospheric Conditions ◽  
Database Analysis ◽  
Chemical Factors ◽  
Risk Degree ◽  
Physical And Chemical

Abstract The article is a summary of information about evaluation of a risk degree for a brown coal spontaneous ignition which is realized on the base of a database analysis of information about the development of stative quantities and desorbated gases in the stored bodies of the brown coal. The data were gained from the long term complex measurements which were realized at chosen companies during the coal mining in the previous parts of the project. In the last part of the project, we examined results of temperature models from thermographs with results of gasses and coal samples from the mines. Then, the influence of atmospheric conditions (insolation, water downfall, changes of barometric pressure etc.), the influence of coal mass degradation, the influence of physical and chemical factors, and the influence of other defective factors on the process of the coal spontaneous ignition. The gasmetry was assess with gas in-situ samples and laboratory gas models of indicative gasses for the spontaneous ignition, which were taken from the method of the thermic oxidation with the aim of the correlation finding for an epicentre of temperature within the spontaneous ignition.

Analysis on Relationship of Chlorophyll-a and Environmental Factors in Wuliangsuhai Lake

2012 ◽  
Vol 178-181 ◽  
pp. 804-807
Author(s):  
Zhong Feng Jiang ◽  
Chang You Li ◽  
Sheng Zhang
Keyword(s):  
System Theory ◽  
Environmental Factors ◽  
Chlorophyll A ◽  
Grey System Theory ◽  
Grey System ◽  
Connection Method ◽  
Chemical Factors ◽  
Research Relationships ◽  
Relationship Of ◽  
Physical And Chemical

Using grey system theory to research relationships between Chlorophyll-a and environmental factors in Wuliangsuhai lake was done in the present study. The effects of physical and chemical factors on chlorophyll-a in Wuliangsuhai lake, were evaluated by using of the gray connection method, providing a row order of those effects, and creating the “advantage factors” that exhibited the greatest effects on chlorophyll-a in wuliangsuhai lake, including temperature、illumination、EC、SD.

scholarly journals Effect of lockdown on wastewater characteristics: a comparison of two large urban areas

2020 ◽  
Vol 82 (12) ◽  
pp. 2813-2822
Author(s):  
Marie-Noëlle Pons ◽  
Pauline Louis ◽  
Davide Vignati
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Noticeable Effect ◽  
Kjeldahl Nitrogen

Abstract The effect of the lockdown imposed to limit the spread of SARS-CoV-2 in France between March 14 and May 11, 2020 on the wastewater characteristics of two large urban areas (with between 250,000 and 300,000 inhabitants) was studied. The number of outward and inward daily commuters was extracted from national census databases related to the population and their commuting habits. For urban area A, with the larger number of daily inward commuters (110,000, compared to 53,000 for B), lockdown was observed to have an effect on the monthly load averages of chemical oxygen demand, biochemical oxygen demand, total Kjeldahl nitrogen, total suspended solids and total phosphorus, all of which decreased (confidence level of 95%). This decrease, which varied between 20% and 40% and reached 45% for COD, can be related to the cessation of catering and activities such as hairdressing, which generate large amounts of graywater. The ammonium loads, due to the use of toilets before leaving for work and after returning from work, remained constant. In the case of urban area B, lockdown had no noticeable effect. More data would be necessary in the long term to analyze the effect of changes in the balance between ammonia and carbon sources on the operation of wastewater treatment plants.

scholarly journals Long-Term Performance of a Full-Scale Membrane Plant for Landfill Leachate Pretreatment: A Case Study

Membranes ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 52 ◽  
Author(s):  
Ester Coppini ◽  
Laura Palli ◽  
Donatella Fibbi ◽  
Riccardo Gori
Keyword(s):  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Full Scale ◽  
Landfill Leachates ◽  
Treatment Train ◽  
Long Term Performance ◽  
Term Performance

This paper presents a case study describing a full-scale membrane bioreactor (MBR) for the pretreatment of landfill leachates. The treatment train includes an aerated equalization tank, a denitrification tank, an oxidation/nitrification tank, and two ultrafiltration units. The plant has worked continuously since 2008 treating landfill leachates at a flux of 2–11 L·h−1·m−2. The old train of membranes worked in these conditions for more than seven years prior to being damaged and replaced. The permeability (K) of the membrane varied between 30 and 80 L·h−1·m−2·bar−1 during the years of operation. In 2010, after two years of operation, the oxidation/nitrification tank was changed to work in alternate cycles of aerated and anoxic conditions, in order to improve the denitrification process. The MBR, working at a mean sludge retention time of 144 days and with mixed liquor suspended solids of 17 g/L, achieved high removal rates of conventional contaminants, with more than 98% for Biochemical Oxygen Demand, 96% for ammonium, and 75% for Chemical Oxygen Demand (COD). From the COD balance, half the COD entering was determined to be biologically oxidized into carbon dioxide, while another 24% remains in the sludge. In order to obtain these results, the company used 5.2 KWh·m−3, while spending 0.79 €·m−3.

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

Aeration and Water Hyacinths in Waste Stabilization Ponds

1987 ◽  
Vol 19 (12) ◽  
pp. 265-271
Author(s):  
P. R. Thomas ◽  
H. O. Phelps
Keyword(s):  
Biochemical Oxygen Demand ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Substantial Improvement ◽  
Additional Treatment ◽  
Coliform Bacteria ◽  
Effluent Quality ◽  
Stabilization Ponds ◽  
Water Hyacinths

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.

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