Temperature Effects on Zn(II) Toxicity to Metabolisms of Polyphosphate Accumulating Organisms in Aerobic and Anaerobic Conditions

Though enhanced biological phosphorus removal (EBPR) is a standard technology for removing phosphorus from wastewater, the responsible organisms and relevant mechanisms are complex and not well-understood. Substrate type has been identified as an important factor affecting the competition between polyphosphate accumulating organisms (PAO_s) and glycogen accumulating organisms (GAOs), which are usually dominant in a failedEBPR. In addition, temperature is also considered an important factor in practice governing the efficiency of phosphate removal in EBPR because the population competition between PAO_s and GAO _s is significantly Ref. affected by water temperature. Ref.found that the predominant microbial population changed from PAO _s to GAO _s when temperature gradually rose from 20°C to 35°C. Similarly found PAO_s were the dominant microorganisms at low temperature (10°C), regardless of the influent carbon source or pH. 

However found conflicting results. Heavy metal ions have also been reported to be able to inhibit biological reactions responsible for carbon, nitrogen and phosphate removals. Ref.found that the presence of Cd (II) significantly changed the structure of microbial population and was toxic to the bacterial community in nutrient removal sludge, especially to the bacteria in the Beta proteobacteria. Monitoring of a full-scale advanced municipal wastewater treatment plant showed the P removal efficiency decreased dramatically after tin (Sn) levels in the solids fraction of the mixed liquid suspended solids (MLSS) exceeded 4 μgSn L^-1 . A similar study by showed 2 mg L^-1 of Cd(II) took the lead in affecting biological phosphate removal. At the level of 5 mg L^-1 of Cd (II), the total nitrogen removal and nitrification efficiency substantially declined and the denitrification rate was inhibited by about 61%. At the same time, the inhibition percentages of anaerobic release, anoxic and aerobic uptake rates of phosphate were about 76, 64, and 90%, respectively Ref.Further conducted a series of batch experiments to identify the toxic effects of Pb(II), Ni(II) and Cd(II) on nitrification and denitrification for nutrient removal sludges.(Read more)

Effect of Climate Changes on Surviving of Nitzschia inconspicua Grunow

The climate is changing at a rate never seen before. Aquatic organisms are endangered throughout the world for various reasons, including global climate change. Changes in precipitation and temperature will dramatically affect the survival of many species. Plants play a key role in moderating climate change becausethey take up carbon dioxide (CO2). If plants are lost, the carbon (as CO2) will continue accumulating in our atmosphere and causes air temperature to rise, leading to ocean acidification. With climate changes, aquatic environments face increases in oceans salinity and sea level rise due to melting of the ice in the poles. These combined factors result in drastic world destruction. 

Organisms need specific conditions in order to survive. Scientists predict that these conditions will be altered when the global climate changes. A change insalinity and temperature could lead to death, migration, or poor health of the living organisms. The loss of aquatic environments will be a major disasterthat will take place because of previous changes

Determination of Selenium in Environmental Samples Using Hydride Generation Coupled to Atomic Absorption Spectroscopy

A hydride technology coupled to atomic absorption spectroscopy HGAAS technique is offered for the willpower of Selenium content material in soil samples, alfalfa, animal feed, and water samples. The selenium distribution was studied in various locations in Zawia metropolis. The studied regions had been divided to seven one of a kind zones. The samples were digested in a aggregate of mineral acid (HNO3, HCL, HCLO4 and H2O2). The Selenium detail in acidified pattern solution was decreased immediately through treating it with Sodium borohydride (NaBH4), the steel hydride changed into added to the atomizer of AAS via inert service gasoline (N2, He). The device used for the era of hydride changed into home built in the analytical lab and a batch method changed into carried out. The analytical parameters had been optimized for the duration of the analytical process to offer standard sensitivity (zero.0055 pg/g). The Atomic Absorbance profile changed into recorded for all measured samples; the obtained signal profiles display smooth peaks. 

 

The Absorption fee at the peak top changed into used as a basis for the analytical calculations. A calibration curve of general selenium concentrations in opposition to absorbance became plotted and used to determine the selenium attention in each sample. Soil samples were analysed by using (HGAAS) for dedication of attention of selenium consequences are stated for all the studied zones, some zones did now not surpassed the said essential toxicity values (1.zero-5.zero pg/g), however another zones are relativity excessive (5.6-five.9 pg/g). The Selenium content material in alfalfa from special zones is particularly low within the variety of (zero.7 to2.20 pg/g). Concentrations of selenium in some animal feed samples are exceedingly low and displaying deficiencies (0.sixty two-zero.71 pg/ g), but different samples are particularly high and were close to the lower limits for high dose (1.41-1.98 ng/g).