Kimyasal şartlandırılmış çamur ile dondurma/çözme ile şartlandırılmış çamurun su verme özelliklerinin karşılaştırılması

Yıl 2018, Cilt: 24 Sayı: 6, 1157 - 1160, 18.12.2018

Gülbin Erden , Ayşe Filibeli

Öz

Bu
çalışmanın amacı kimyasal olarak şartlandırılmış çamur ve dondurulup
çözdürülmüş çamurun su verme özelliklerinin özgül filtre direnci (ÖFD), çamur
keki katı madde içeriği (KM) ve kapiler emme süresi (KES) parametre
değerlerinin belirlenmesi ile karşılaştırılmasıdır. Deneysel çalışmada, İzmir
(Türkiye)’de bulunan bir kentsel atıksu arıtma tesisi çamurları kullanılmıştır.
Kimyasal şartlandırma deneylerinde çamurlar farklı dozlardaki polimer ile
klasik jar testi metodu kullanılarak şartlandırılmıştır. Dondurma/çözme yöntemi
ile şartlandırma çalışmalarında ise çamur örnekleri -16.5 °C’de farklı donma
hızlarında dondurulmuş ve sonra 21±1 °C’de çözme süresinin su alma
performansına etkisini belirlemek amacıyla farklı çözme sürelerinde
çözdürülmüştür. 25 mg/L polimer dozu ve 2.71 mm/sa. donma hızı çamur şartlandırma için en uygun koşul olarak
belirlenmiştir. 8.13 mm/sa.’ten daha hızlı dondurma işlemi çamurun
şartlandırılması için yeterli olmamıştır. Yanı sıra, çözme süresinin çamur
şartlandırma performansı üzerinde önemli bir etkisi olmadığı belirlenmiştir.
Çalışmanın bir sonucu olarak, kimyasal şartlandırılmış çamur ile dondurma/çözme
ile şartlandırılan çamurların su verme özellikleri birbirine oldukça yakın
olduğu belirlenmiştir. 25 mg/L polimer uygulamasında KES ve ÖFD değerlerindeki
azalma sırasıyla %76 ve %75 iken ve 2.71 mm/sa. dondurma hızı uygulaması
sırasıyla  %79 ve %76 KES ve ÖFD
azalmasına sebep olmuştur. Çalışmanın diğer bir sonucu ise dondurma/çözme ile şartlandırılmış
çamurların kimyasal şartlandırılmış çamurlara oranla vakum filtrasyonu
sonrasında daha yüksek katı madde içeriklerine ulaşmasıdır.

Anahtar Kelimeler

Çamur, Susuzlaştırma, Kimyasal şartlandırma, Polimer, Dondurma/Çözme

Comparison of dewatering characteristics of chemically conditioned sludge and freeze/thawed sludge

Öz

The
objective of this study was to compare dewatering properties of chemically
conditioned sludge and freeze/thawed sludge as determined by mainly specific
resistance to filtration (SRF), dry solids content of sludge cake (DS), and
capillary suction time (CST) parameters. The experimental studies were carried
out with mixed sludge samples taken from a municipal wastewater treatment plant
in Turkey. In chemical conditioning experiments, sludge samples were
conditioned with different dosages of polymer using classical jar test method.
In freeze/thaw conditioning experiments, samples were frozen at -16.5 °C at
different freezing rates and then thawed at 21±1 °C at different times in order
to determine the effect of thawing time on dewatering performance. 25 mg/L
polymer dose and 2.71 mm/h freezing rate were found to be optimum in terms of
sludge conditioning. Rapid freezing that is higher than 8.13 mm/h could not
sufficiently condition the sludge and there was no significant effect of
thawing time on conditioning performance. Dewatering properties of chemically
conditioned sludge and freeze/thawed sludge was determined as very close to
each other. While CST and SRF reductions were calculated as 76% and 75%,
respectively at 25 mg/L polymer dosage, 2.71 mm/h freezing rate application
caused 79% and 76% reduction in CST and SRF, respectively.

Anahtar Kelimeler

Sludge, Dewatering, Chemical conditioning, Polymers, Freeze/Thaw

Kaynakça

• Egemen E, Corpening J, Nirmalakhandan N. “Evaluation of an ozonation system for reduced waste sludge generation”. Water Science and Technology, 44(2-3), 445-452, 2001.
• Tuan PA, Mika S,Pirjo I. Sewage Sludge Electro-Dewatering Treatment-A Review. Drying Technology, 30(7), 691-706, 2012.
• Bougrier C, Carrère H, Delgenes JP. “Solubilisation of waste-activated sludge by ultrasonic treatment”. Chemical Engineering Journal, 106(2), 163-169, 2005.
• Dentel SK. Sludge into Biosolids: Processing, Disposal, Utilization. IWA Publishing, 2001.
• Eckenfelder WW, Santhanam CJ. Eds: Sludge Treatment, Marcel Dekker, Inc. Newyork and Basel, 1981.
• Dursun D, Ayol A, Dentel SK. “Physical characteristics of a waste activated sludge: Conditioning responses and correlations with a synthetic surrogate”. Water Science and Technology, 50(9), 129-136, 2004.
• Gao W. “Freezing as a combined wastewater sludge pretreatment and conditioning method”. Desalination, 268(1-3), 170-173, 2011.
• Mahmoud A, Olivier J, Vaxelaire J, Hoadley AFA. “Electro-dewatering of wastewater sludge: Influence of the operating conditions and their interactions effects”. Water Research, 45(9), 2795-2810, 2011.
• Liu H, Yang J, Shi Y, Li Y, He S, Yang C, Yao H. “Conditioning of sewage sludge by Fenton’s reagent combined with skeleton builders”. Chemosphere, 88(2), 235-239, 2012.
• Erden G, Filibeli A. “Effects of fenton pre-treatment on waste activated sludge properties”. Clean-Soil, Air, Water, 39(7), 626-632, 2011.
• Feng X, Deng JC, Lei HY, Bai T, Fan QJ, Li ZX. “Dewaterability of waste activated sludge with ultrasound conditioning”. Bioresource Technology, 100(3), 1074-1081, 2009.
• Dentel SK, Abu-Orf MM, Griskowitz NJ. Guidance Manual for Polymer Selection in Wastewater Treatment Plants, Publ. D0013, Water Envt. Research Foundation, Alexandria, Va, 1993.
• Dentel SK, Abu-Orf MM, Griskowitz NJ. Polymer Characterization and Control in Biosolids Management, Publ. D43007, Water Environment Research Foundation, Alexandria, Va, 1995.
• Werle CP, Novak JT. “Mixing Intensity and Polymer Conditioning”. ASCE Journal of Environmental Engineering, 110, 919-934, 1984.
• Christensen JR, Sorensen PB, Christensen GL, Hansen J. “Mechanisms for overdosing in sludge conditioning”. Journal of Environmental Engineering, 119, 159-171, 1993.
• Lee DJ, Hsu YH. “Fast freeze/thaw treatment on activated sludge: Floc structure and sludge dewaterability”. Environmental Science & Technology, 28, 1444-1449, 1994.
• Lee DJ, Hsu YH. “Measurement of bound water in sludges: a comperative study”. Journal of Chemical Technology and Biotechnology, 61, 139-144, 1995.
• Randall CW, Khan MZ, Stephens NT. “Waste activated sludge conditioning by direct slurry freezing”. Water Research, 9, 1917-925, 1975
• Chen LC, Chian CY, Yen PS, Chu CP, Lee DJ. “High speed sludge freezing”. Water Research, 35(14), 3502-3507, 2001.
• Hung WT, Chang IL, Lin WW, Lee DJ. “Uni-directional freezing of waste activated sludges: Effect of freezing speed”. Environmental Science and Technology, 30, 2391-2396, 1996.
• Kawasaki, K, Matsuda DG. “Freezing and thawing of excess activated sludge to improve the solid liquid separation characteristics”. 6th World Fil. Cong. Nagoya, Japan, 1993.
• APHA, AWWA, and WEF, Standard Methods for the Examination of Water and Wastewater, 21th ed. American Public Health Association, Washington, DC, 2005
• Meeten GH, Smeulders JBAF. “Interpretation of filterability measured by the capillary suction time method”. Chemical Engineering Science, 50(8), 1273-1279, 1995.