1,721,442 research outputs found
Effect of increasing the organic loading rate on the co-digestion and mono-digestion of cattle slurry and maize
No full textWaste as a resource: a discussion paper on the changes needed for the development of a resource recovery based waste strategy
No full textThe Elmer Record
No full textWeekly newspaper from Elmer, Oklahoma that includes local, state, and national news along with advertising
Salinity from space
No full textAlthough ocean salinity is a key parameter for determining the ocean circulation on local and global scales, measuring salinity from space has only been possible since the launch of the European Space Agency’s Soil Moisture and Ocean Salinity (SMOS) mission in November 2009. This is in contrast to the other key oceanographic parameter temperature, which has been measured from space using satellite sensors since the 1970s. Traditionally, oceanographers have used ship-based measurements to observe ocean temperature and salinity. Here the rationale for measuring salinity from space is explained and the technical advances that have made this possible are described. Some examples are given of how the recently available sea surface salinity measurements from space have provided new insights into oceanographic phenomena
The removal of lindane from aqueous solution using a fungal biosorbent: the influence of pH, temperature biomass concentration and culture age
No full textA heat treated non viable cell suspension of the fungus Rhizopus oryzae was used for the removal of low concentrations of lindane from aqueous solution in a series of shake flask experiments. Experimental design was such as to allow the data to be tested against the Freundlich adsorption isotherm model thus quantifying the effect of experimental variables on both the adsorption capacity and intensity of adsorption exhibited by the fungus. The effects of temperature (5-45°C), pH (2.0-10), biomass density (1-12 g l-1) and biomass age (1-7 days) were studied. The results indicated that the mechanism of adsorption was by physical bonding of the negatively charged lindane molecule to the negatively charged fungal cell wall with hydrogen ions acting as the bridging ligand. Adsorption was most effective at low temperature and pH and was shown to be influenced, to a lesser extent, by cell density and biomass age. Data are presented in the form of adsorption isotherms and the Freundlich parameters associated with each of the experimental variables tabulated
Removal of copper from aqueous solution by ascophyllum nodosum immobilised in hydrophilic polyurethane foam
No full textThe seaweed Ascophyllum nodosum was pre-treated by successive washes in distilled water and dilute acid, dried, and pulverised to produce particles of < 150 mum. These were immobilised during the manufacturing process of Hypol 2002 polymer to form a biomass/polymer matrix that was stable and easy to handle. In making the composite a mixing speed of 360 rpm for 20-30 s with 2% (w/w) addition of surfactant to pre-polymer was found to be ideal. The average pore sizes for different water polymer mixes (expressed as volume ratios) were 1.66 mm +/- 0.98 (ratio 0.75:1), 1.58 mm +/- 0.76 (ratio 1:1), 1.64 mm +/- 0.6 (ratio 1.5:1) and 1.11 mm +/- 0.615 (ratio 2:1).
The biomass/polymer was used alongside free native biomass in an initial adsorption experiment using a 0.0315 mmol dm(-3) Cu (II) solution and gave a copper uptake capacity (q(max)) of 0.037 mmol Cu g(-1) dry weight seaweed in both cases which represented approximately 85% of total initially available copper. In later adsorption isotherm experiments using Cu concentrations between 0.0315 and 0.944 mmol dm(-3) at pH 5.0 and immobilized biomass over five consecutive adsorption/desorption cycles the biomass/polymer showed an initial lowering of adsorption capacity but stabilised at 0.23 mmol g(-1) dry weight by the third re-use. The q(max) of the immobilised biomass decreased from 0.55 and 0.416 mmol of Cu g(-1) dry weight when pH was lowered from 4.0 to 3.0, and increased from 0.576 mmol g(-1) dry weight (biomass) at 283 K to 0.636 mmol g(-1) (biomass) at 303 K
The use of sequencing batch activated sludge reactors to determine nitrogen balances and optimum periods of pre-aeration denitrification
No full textFour identical laboratory scale sequencing batch activated sludge plants were used to carry out comparative performance evaluations of nitrification and denitrification, and to obtain an accurate nitrogen balance for the system. In the first instance the plants were run under identical operational conditions to ensure that results were statistically valid. Ten performance parameters were compared and no significant differences at 95% confidence limits were found. A nitrogen mass balance, considering dissolved nitrogen species, waste biomass and denitrification losses during settlement, accounted for 87.4% of known inputs. On the introduction of denitrification periods, nitrate and total nitrogen removal increased with increasing anoxic period up to a maximum of 74% and 71% respectively. The inclusion of anoxic periods reduced total organic carbon (TOC) removal by as much as 19%. These losses are a consequence of maximising nitrate removal when the cycle duration is fixed. This is due to differences in efficiency between aerobic and denitrifying activity. Good linear relationships were shown between % nitrogen removal (r=0.93), effluent nitrate concentration (r=-0.94), T.O.C. removed (r=-0.99) and the ratio of anoxic to aerobic retention times; this was providing the anoxic period was taken to be the period of nitrate removal. These relationships may provide a guide for designing sequencing batch nitrification /denitrification systems. Some enhancement of nitrification was also evident at short denitrification phases
Evaluation of instability and performance of an upflow anaerobic sludge blanket (USAB) reactor treating high-strength ice cream wastewater
No full textAnaerobic digestion of solid and high nitrogen content fractions of slaughterhouse wastes
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