The Process Design Of Flotation-Sedimentation Basin And The Study On The Treatment Of Low Temperature And Low Turbidity Reservoir Water Derived From Yellow River

This study is the the Sub-topics of "Research and Demonstration of Strengthening Conventional Process Integration Technology to the Yellow River Reservoir with High Algae", which is from the third topic of" the Research and Demonstration of the Drinking Water Security Technology System" of "Major Science and Technology Program for Water Pollution Control and Treatment", named " the Research and Demonstration of the Drinking Water Security Technology in the Lower Reaches of Yellow River". This paper is part of the research of "the Research and Demonstration of Flotation Technology as the Core of the Integration " (2008ZX07422-003-003).The water quality characteristics of the reservoir water derived from Yellow river (Queshan reservoir in Jinan city) are low temperature, low turbidity. Based on those characteristics, the flotation-sedimentation basin was designed and was studied deeply about the treatment of the low temperature and low turbidity reservoir water derived from Yellow river by the flotation-sedimentation basin process in this paper.The contents of study include three aspects:(1)the design of the flotation-sedimentation basin; (2) the optimum study of operating parameters on the flotation-sedimentation basin technology in low temperature and low turbidity; (3) the treatment effect study of the flotation-sedimentation basin technology in low temperature and low turbidity.In order to better carry out and complete research assignments,Based on those characteristics of the reservoir water derived from Yellow river, the flotation-sedimentation basin was designed and made independently.It is introduced in this paper that the flotation-sedimentation basin and the design specifications, design features and equipment models of the design, the design of the coagulation unit and the dosing unit and the medication calculation of the flotation-sedimentation basin, the design of the dissolved air flotation unit,the air saturated equipment, the release of dissolved gas water decompression device and the scraping slag system of the flotation-sedimentation basin and the design of the sedimentation area and the water arranged area of the Precipitation area of the flotation-sedimentation basin.In the optimum study of the flocculation condition, the coagulation effect of PAFC, PAFC-PD and PFASiC is tested and PFASiC is suited for reservoir water derived from Yellow river. The optimum dosage of PAFSiC is 2.0mgAl3+/L, and the optimum coagulant added position is back of the pump.In the optimum study of operating parameters on the flotation-sedimentation basin technology, through Single factor experiment of different recycle rates, loading rates, effluence position. Results show that the optimum recycle rate is 11%, the loading rate is not exceed 5 m3/(m2·h), the optimum effluence position is under the askew pipeline and the optimum cycle time of scrape residue is 4 h. From the orthogonal test, we can see that optimum parameters of the water flow, the recycle rates, the mixing speed and the flocculation speed are 5 m3/d,11 %,130 r/min,400 r/min.From the test of the dross components and the study of dydisposal technologies,in the dross of the flotation-sedimentation basin, the moisture content, the gas rate, Nitrogen and phosphorus compounds are high, but it can change the dross performance, reduce the water content, reduce the volume of dross by adding the coagulant.It is very marked that the reservoir water derived from Yellow river (low temperature and low turbidity) is dealed with the flotation-sedimentation basin, and the removal rates of turbidity, CODMn, UV254, TOC, Ammonia are high. and the turbidity of effluence is less than 1.0NTU in low temperature and low turbidity, Through this technology, the average removal rates of turbidity, CODMn, UV254, TOC and Ammonia are 82.19,15.61,26.08,25.41 and 16.64 % respectively. And the average removal rates of the total number of impurity particles is between 56.43 and 72.78%, the average removal rates of DBPs precursors such as CHCl3,CHClBr2,CHCl2Br,CHCl2Br are 23.04,23.75,19.68 and 14.14% respectively.