Effect of Temperature on Floc Formation Process Efficiency and Subsequent Removal in Sedimentation Process | ||
| Journal of Engineering and Sustainable Development | ||
| Article 1, Volume 18, Issue 4, August 2014, Pages 176-187 | ||
| Author | ||
| Rasha Azeez Joudah | ||
| Abstract | ||
| flocs can be separated from waters depending on their stability, size, density, etc., and according to literatures the velocity gradient of the flow is the main design parameter of the flocculators, but there is a need to take into account at least the flocs age, and the effect of temperature too. This paper will study these factors. Temperature is known to affect flocculation and settling phenomena. Jar tests have been conducted in the sanitary laboratory of Almustansiriya University using square jar test apparatus to assess the effects of temperature on floc formation and settling efficiency. For raw water turbidities of 500 and 1000 NTU, the results show that the decrease in water temperature will impair the floc strength and virtually floc formation efficiency and causing bad settling, therefore prolonged flocculation time at low temperatures will break the big formed flocs into smaller ones again and reduce settling efficiency, thus in winter care must be taken in drinking water plant to set suitable flocculation time. It was also observed that the effect of temperature on floc formation and strength becomes less effective with increase the initial turbidity. The effect of flocculation velocity gradient on floc formation and strength, at low temperature was significant, but as temperature increases the effect will be less. Better results of turbidity removal had appeared when velocity gradient was increased from 10, to 20 then to 30 and 40 S-1. At normal temperature range for water treatment, the increase in flocculation time above 40 min. shows impairment of floc formation and virtually bad selling. | ||
| Keywords | ||
| temperature; Flocculation; Floc formation; settling; jar test | ||
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