Effect of Low-Temperature Treatment on Sludge Dewatering Characteristics NSC-88-2218-E-009-030 87 / 08 / 01 - 88 / 07 /31 !" ( #$%&' ()* + ,-./) 0123456789,-:; 40-85 <=>?@ ABCDEFGH5+ B"IJKLMNBOP?QR;STU ,-./VWX,-YZ[\]^_`a 9"I?bcdef9ghijkl ,-9m./Enopqr(]s?t uOPHpqr(]sBvw[xDy ;z{?|ol}~Bx[lB ?V I./,-i ?b&'`/Bx? ]r()*+x?I ^ ]9./i? ¡ x&'`/BS¢£¤¥¦?§¨ ©ª«9¬?,-95 ®¯[° ±²y;³´µi¶'¦·¸V ¥?¹5²º»¼9´½i§&'` /]()*+./¾¿ÀÁÂÃ95 ÄÅ?Æ@V&'`/V±&pqr(] s9xDÇd ¿9Oi È ! " (keyword: Low-Temperature, polyelectrolyte, sludge conditioning)
Approximately six hundred thousand tons of sludge is produced annually from the water treatment plants in Taiwan. This amount is expected to increase astronomically due to the increasing demand for more quality water and the more stringent regulations regarding wastewater treatments implemented by the Government. How to minimize the sludge volume and optimize the sludge
condition for final disposal in an efficient way has become the focus of many studies. Traditionally, sludge is conditioned chemically by using polymers. The current law forbids the discharge of wastewater containing certain types of polymers into water bodies, which limits the use of polymers. Other disadvantages of using polyelectrolytes include their significant cost and safety concerns. Therefore, it is necessary to search for other options for sludge conditioning. In this study, the feasibility of low-temperature treatment was evaluated. Cationic polyelectrolyte was also applied with the low-temperature treatment to search for alternative for efficient conditioning.
Experimental results indicate that the success of low-temperature treatment relies on the degree of freezing. After the freezing/thawing stage, the dewaterability, filterability and settling properties were all improved greatly. If the temperature was not low enough to freeze the sludge, no significant change in dewatering characteristics was observed. When low-temperature treatment was combined with polyelectrolyte conditioning, the improvement in dewatering rate was better than chemical conditioning alone, suggesting that low-temperature treatment may replace the use of polymer to some extent.
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Minyih Cherng, Chihpin Huang and Jill Rushing Pan, (1999) Effect of Solid/Liquid Separation Processes on Sludge Conditioning - Settling vs. Flotation ÌD 1 No. TSS (mg/L) VSS (mg/L ) pH D (cm) Zeta potential (mV) eff (g/cm3) 871020 80556 1243.8 7.06 0.0256 -6.69 0.3076 871130 43820 665.4 7.50 0.0133 -13.0 0.8189 0 250 500 750 1000 1250 1500 1750 2000 -8 0 8 16 24 Temperature () T85% (sec) 0 1 2 3 4 5 6 3 .3 .5 T85% 1 !"#$%& 2 '()*+,-./01" 2345 678293 Polymer Dose (mg/l) : 4; -4; 0 0.1329 0.2004 0.4097 8 0.2778 0.2689 0.6484
15 0.2798 0.3115 1.1052 20 0.4633 0.4306 0.5972 30 0.4454 0.5278 0.8075 40 0.6746 0.5625 0.8175 D<6723 (cm) 3 '()*+,-./01 "=>? =>? Polymer Dose (mg/l) : 4; -4; 0 0.8191 0.4239 0.4415 8 0.2678 0.2356 0.1822 15 0.3024 0.2709 0.0700 20 0.2479 0.1962 0.1232 30 0.2485 0.1172 0.1414 40 0.1557 0.1140 0.1341 eff@=>? (g/cm3) 0 2 4 6 8 10 12 14 16 0 10 20 30 40 P oly me r dose ( mg/ l) SVI (mL/g) 2 '()*+,-./0A BCD "EF 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0 5 10 15 20 25 30 35 40 polymer dose (mg/l) (Tm/kg) 3 '()*+,-./0AGHIJ"EF 0 50 100 150 200 250 300 350 400 450 0 10 20 30 40 polymer dose (mg/l) T85% (sec ) 4 '()*+,-./0A !"EF 30 35 40 45 50 55 0 10 20 30 40 Polymer Dose (mg/l)
Water content of sludge cake (%
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