The effect of dissolved oxygen, sediment, and sewage treatment plant discharges upon growth, survival and density of Asiatic clams

Hydrobiologia ◽  
1991 ◽  
Vol 218 (2) ◽  
pp. 113-126 ◽  
Author(s):  
Scott E. Belanger
1972 ◽  
Vol 7 (1) ◽  
pp. 13-20
Author(s):  
D.D.P. Cane ◽  
G.J. Farguhar

Abstract A case of filamentous activated sludge bulking was investigated at an extended aeration plant treating wastes from a highway service centre. The purpose of the study was to find an effective control measure for the bulking and, if possible, to determine the cause of the bulking condition. Experiments were conducted to determine the effects upon bulking of: (a) a controlled copper dosage to the mixed liquor, (b) variations in the organic loading rate, and (c) maintenance of high and low dissolved oxygen concentrations in the mixed liquor. The microorganism responsible for the bulking condition was tentatively identified as Sphaerotilus natans. Extensive growths of these bacteria occurred in the sludge when the mixed liquor dissolved oxygen concentration dropped below 0.5 mg/1. Such dissolved oxygen levels had frequently occurred at this plant due to the use of timed aeration cycles and the use of insufficient air supply during peak loading periods. Variations in organic loading rates were found to have no adverse effect on sludge settleability. When bulking was slight, the condition could be improved by increasing the dissolved oxygen level to 1.5 mg/1, or more. The rate at which the filamentous growths could be eliminated from a highly filamentous sludge by increased aeration was very slow, but could be greatly increased by the simultaneous feeding of copper to the mixed liquor at a dosage rate of 1.0 mg/1, based on the raw sewage flows.


2013 ◽  
Vol 328 ◽  
pp. 297-303
Author(s):  
Si Mei Zhang ◽  
Lu Liu ◽  
Shu Heng Hu

Orbal oxidation ditch is widely used in urban sewage treatment system ,Oxygen consumption level is an important index to measure process operating characteristic, discuss the operation mode of Oxidation ditch under low dissolved oxygen concentration condition is the main link of Sewage plants energy saving operation. Through the adjustment of chongqing TongLiang sewage treatment plant Orbal oxidation ditch aerations equipment operation parameters, the operating power reduced 7.5 kW, the removal rate of TN increased from 19% to more than 50%,and COD, BOD5, TP, NH3 - N removal rate was not affected, the Water meet the design requirements.


2012 ◽  
Vol 610-613 ◽  
pp. 1509-1512
Author(s):  
Xiao Nan Zhang ◽  
Shi Qiang Ding ◽  
Ji Run Xu

By a circular operation of anaerobic mixing - aerobic aeration – sediment drain, a sludge with low activation obtained from a common sewage treatment plant is acclimated in laboratory. The acclimation is performed with simulated sewage and composed of three periods. In the every period, the sewage concentration is successively increased, the removal percentage of COD, NH4+-N and TP are measured, when the removal is stable, the period is transformed to next one. The outside and construction characteristics of the activated sludge are observed and the protozoon is examined. Meanwhile, some influence factors such as temperature, dissolved oxygen and pH are analyzed. The experiments show that the acclimated activated sludge is able to remove the COD, NH4+-N and TP effectively under a suitable but easy-to-be obtained conditions.


2020 ◽  
Vol 15 (2) ◽  
pp. 142-151
Author(s):  
Peter Lukac ◽  
Lubos Jurik

Abstract:Phosphorus is a major substance that is needed especially for agricultural production or for the industry. At the same time it is an important component of wastewater. At present, the waste management priority is recycling and this requirement is also transferred to wastewater treatment plants. Substances in wastewater can be recovered and utilized. In Europe (in Germany and Austria already legally binding), access to phosphorus-containing sewage treatment is changing. This paper dealt with the issue of phosphorus on the sewage treatment plant in Nitra. There are several industrial areas in Nitra where record major producers in phosphorus production in sewage. The new wastewater treatment plant is built as a mechanicalbiological wastewater treatment plant with simultaneous nitrification and denitrification, sludge regeneration, an anaerobic zone for biological phosphorus removal at the beginning of the process and chemical phosphorus precipitation. The sludge management is anaerobic sludge stabilization with heating and mechanical dewatering of stabilized sludge and gas management. The aim of the work was to document the phosphorus balance in all parts of the wastewater treatment plant - from the inflow of raw water to the outflow of purified water and the production of excess sludge. Balancing quantities in the wastewater treatment plant treatment processes provide information where efficient phosphorus recovery could be possible. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. The mean daily value of P tot is approximately 122.3 kg/day of these two sources. There are also two outflows - drainage of cleaned water to the recipient - the river Nitra - 9.9 kg Ptot/day and Ptot content in sewage sludge - about 120.3 kg Ptot/day - total 130.2 kg Ptot/day.


2008 ◽  
Vol 37 (2) ◽  
Author(s):  
Maciej Walczak

Changes of microbial indices of water quality in the Vistula and Brda rivers as a result of sewage treatment plant operationThis paper reports the results of studies of microbiological changes in the water quality of the Vistula and Brda rivers after the opening of sewage treatment plants in Bydgoszcz. The study involved determining the microbiological parameters of water quality. Based on the results obtained, it was found that the quality of the water in both rivers had improved decidedly after the opening of the plants, although an increased number of individual groups of microorganisms was found at the treated sewage outlet from one of the plants.


2000 ◽  
Vol 36 (4) ◽  
pp. 161-171
Author(s):  
KENITSU KONNO ◽  
NAOKI ABE ◽  
YOSHIRO SATO ◽  
KOJI AKAMATSU ◽  
MAKOTO ABE ◽  
...  

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