| In recent years, the number of domestic water plant growing, and the scale of new plant are larger. At the same time, the sluge water producted in drinking water productive process is suddenly increased, which occupied about 4% -7% of total water .The current water shortage situation will be relieved if the sludge water reused.The existing sludge treatment process mainly contains the traditional concentration process and a new concentration tank, which all based on "concentrate- conditioning-dehydration." Their common features are relative stable effluence, convenient operation or management and so on, but the traditional process exists problems of covering great area, more treatment structures, buildings complexly and so forth.Compared with conventional flocculation process, Pellet flocculation Blanket Process as a new Processing Technology has advantages such as high density of pellet and Hydraulic loading, lower Sludge moisture content, smaller covering area, Easy to implement automatic control and etc. So the application prospect of Pellet flocculation Blanket Process is broad.In this paper, by taking the wastewater from Yangliuqing water plant in Tianjin City as the object, dynamic and productive experimental study are carried out respectively on concentrating ferric flocs sludge water by pellet flocculation process with capacity of 0.6～1.2m3/h and 10～40m3/h. Experimental results shows that:(1) Under the Pilot experimental conditions, TS of inflow was 278mg/L,the mixing intensity was 6rpm,the rate of inflow was 600L/h, When the PAM dosage increased from 0.59mg/L to 1.18 mg/L, the turbidity of outflow decreased from 8NTU to 6NTU, particle free settling velocity increased from 3mm/s to 7mm/s, The volume concentration of flocs blanket increased from 0.2 to 0.3, Average pellet size increased from 1.8mm to 2.8mm; The optimum PAM dosage increased from 1.18mg/L to 1.62mg/L when the TS of inflowing increased from 278mg/L to 840mg/L; Under certain experimental conditions, Average pellet size of pellet decreased with the mixing intensity increased; The volume concentration of flocs blanket decreased as the upflow rate increased.(2) At lower TS conditions, effect of the point of recycling sludge after the PAM dosage point is better than the front of the PAM dosage point; The optimal ratio of recycling sludge was between 2% and 8%, and increased with the upflow rate rose.Concentration of the recycling sludge was about 5g/L, the optimal volume of recycling sludge was between 60～400g/h.(3) Under the Productive experimental conditions, TS of the inflow was about 400mg/L, the Optimal dosage of PAM was 1.2mg/L, Stirring intensity of 2～4r/min was appropriate, the largest upflow ritao was 66cm/min, the least Sludge moisture content was less than 96%.(4) Under the Productive experimental conditions, concentration of the wastewater in water plant was range of 100～600mg/L, Through real-time monitoring of four seasons, the experimental outflow turbidity was all satisfied Discharge water reusing turbidity requirements (≤20NTU), effluent turbidity level of summer was higher than the other seasons; the effluent turbidity was increased gradually when the influent TS increased sharply; Developed the automatic system to stable the turbidity of the effluent in different inflow velocity and different inflow TS by control the PAM dosage automatically, and to achieve discharge sluge automatically.(5) By the relevant water quality testing, content of PAM monomer of effluent in Pellet Coagulation Process was much smaller than Provision of our "drinking water health standard" (BG5749-2006), so the treated effluent can be reused directly. |
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