Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness and statistical optimization

Abstract

In this work, the enhanced dewaterabing characteristics of waste activated sludge using Fenton pretreatment was investigated in terms of effectiveness and statistical optimization. Response surface method (RSM) and central composite design (CCD) were applied to evaluate and optimize the effectiveness of important operational parameters, i.e., H₂O₂ concentrations, Fe²⁺ concentrations and initial pH values. A significant quadratic polynomial model was obtained (R²= 0.9189) with capillary suction time (CST) reduction efficiency as the response. Numerical optimization based on desirability function was carried out. The optimum values for H₂O₂, Fe²⁺, and initial pH were found to be 178 mg·g^-1 VSS (volatile suspended solids), 211 mg·g^-1 VSS and 3.8, respectively, at which CST reduction efficiency of 98.25% could be achieved. This complied well with those predicted by the established polynomial model. The results indicate that Fenton pretreatment is an effective technique for advanced waste activated sludge dewatering. The enhancement of sludge dewaterability by Fenton’s reagent lies in the migration of sludge bound water due to the disintegration of sludge flocs and microbial cells lysis.

Keywords

Fenton pretreatment / response surface methodology (RSM) / capillary suction time (CST) / dewaterabilty / molecular weight distribution

References

[1] Feng X, Deng J C, Lei H Y, Bai T, Fan Q J, Li Z X. Dewaterability of waste activated sludge with ultrasound conditioning. Bioresource Technology, 2009, 100(3): 1074–1081

[2] Sakohara S, Ochiai E, Kusaka T. Dewatering of activated sludge by thermosensitive polymers. Separation and Purification Technology, 2007, 56(3): 296–302

[3] Lee C H, Liu J C. Sludge dewaterability and floc structure in dual polymer conditioning. Advances in Environmental Research, 2001, 5(2): 129–136

[4] Watanabe Y, Kubo K, Sato S. Application of amphoteric polyelectrolytes for sludge dewatering. Langmuir, 1999, 15(12): 4157–4164

[5] Li H, Jin Y Y, Nie Y F. Application of alkaline treatment for sludge decrement and humic acid recovery. Bioresource Technology, 2009, 100(24): 6278–6283

[6] Yuan H P, Zhu N W, Song F Y. Dewaterability characteristics of sludge conditioned with surfactants pretreatment by electrolysis. Bioresource Technology, 2011, 102(3): 2308–2315

[7] Pei H Y, Hu W R, Liu Q H. Effect of protease and cellulase on the characteristic of activated sludge. Journal of Hazardous Materials, 2010, 178(1–3): 397–403

[8] Yu Q, Lei H L, Yu G W, Feng X, Li Z X, Wu Z C. Influence of microwave irradiation on sludge dewaterability. Chemical Engineering Journal, 2009, 155(1–2): 88–93

[9] Lu M C, Lin C J, Liao C H, Ting W P, Huang R Y. Influence of pH on the dewatering of activated sludge by Fenton’s reagent. Water Science and Technology, 2001, 44(10): 327–332

[10] Lu M C, Lin C J, Liao C H. Huang R Y, Ting W P. Dewatering of activated sludge by Fenton’s reagent. Advances in Environmetal Research, 2003, 7(3): 667–670

[11] Neyens E, Baeyens J, Dewil R, de heyder B. Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering. Journal of Hazardous Materials, 2004, 106(2–3): 83–92

[12] Kwon J H, Park K Y, Park J H, Lee S H, Ahn K H. Acidic and hydrogen peroxide treatment of polyaluminum chloride (PACL) sludge from water treatment. Water Science and Technology, 2004, 50(9): 99–105

[13] Buyukkamaci N. Biological sludge conditioning by Fenton’s reagent. Process Biochemistry, 2004, 39(11): 1503–1506

[14] Wang X, Niu D J, Yang X S, Zhao Y C. Optimization of methane fermentation from effluent of bio-hydrogen fermentation process using response surface methodology. Bioresource Technology, 2008, 99(10): 4292–4299

[15] Mohajeri S, Aziz H A, Isa M H, Zahed M A, Adlan M N. Statistical optimization of process parameters for landfill leachate treatment using electro-Fenton technique. Journal of Hazardous Materials, 2010, 176(1–3): 749–758

[16] Benatti C T, Tavares C R, Guedes T A. Optimization of Fenton’s oxidation of chemical laboratory wastewaters using the response surface methodology. Journal of Environmental Management, 2006, 80(1): 66–74

[17] Kshirsagar A C, Singhal R S. Optimization of starch oleate derivatives from native corn and hydrolyzed corn starch by response surface methodology. Carbohydrate Polymers, 2007, 69(3): 455–461

[18] Yuan H P, Zhu N W, Song L J. Conditioning of sewage sludge with electrolysis: effectiveness and optimizing study to improve dewaterability. Bioresource Technology, 2010, 101(12): 4285–4290

[19] Ahmad A L, Ismail S, Bhatia S. Optimization of coagulation-flocculation process for palm oil mill effluent using response surface methodology. Environmental Science & Technology, 2005, 39(8): 2828–2834

[20] Tony M A, Zhao Y Q, Fu J F, Tayeb A M. Conditioning of aluminium-based water treatment sludge with Fenton’s reagent: effectiveness and optimising study to improve dewaterability. Chemosphere, 2008, 72(4): 673–677

[21] Mustranta A, Viikari L. Dewatering of activated sludge by an oxidative treatment. Water Science and Technology, 1993, 28(1): 213–221

[22] APHA. Standard Methods for the Examination of Water and Wastewater, 20th ed. Washington, DC, USA: American Public Health Association Inc., 1998

[23] Neyens E, Baeyens J. A review of classic Fenton’s peroxidation as an advanced oxidation technique. Journal of Hazardous Materials, 2003, 98(1–3): 33–50

[24] Badawy M I, Ali M E M. Fenton’s peroxidation and coagulation processes for the treatment of combined industrial and domestic wastewater. Journal of Hazardous Materials, 2006, 136(3): 961–966

[25] Rastogi A, Ai-Abed S R, Dionysiou D D. Sulfate radical-based ferrous peroxymonosulfate oxidative system for PCBs degradation in aqueous and sediment systems. Applied Catalysis B: Environmental, 2009, 85(3–4): 171–179

[26] Zhen G Y, Lu X Q, Zhao Y C, Chai X L, Niu D J. Enhanced dewaterability of sewage sludge in the presence of Fe(II)-activated persulfate oxidation. Bioresource Technology, 2012, 116: 259–265

[27] Adav S S, Lee D J, Tay J H. Extracellular polymeric substances and structural stability of aerobic granule. Water Research, 2008, 42(6–7): 1644–1650

[28] Liu X M, Sheng G P, Luo H W, Zhang F, Yuan S J, Xu J, Zeng R J, Wu J G, Yu H Q. Contribution of extracellular polymeric substances (EPS) to the sludge aggregation. Environmental Science & Technology, 2010, 44(11): 4355–4360

[29] Badireddy A R, Chellam S, Gassman P L, Engelhard M H, Lea A S, Rosso K M. Role of extracellular polymeric substances in bioflocculation of activated sludge microorganisms under glucose-controlled conditions. Water Research, 2010, 44(15): 4505–4516

[30] Stumm W, Morgan J J. Aquatic Chemistry: Chemical Equilibria and Rates in Natural Waters, 3rd ed. New York: Wiley, 1996

[31] Li X Y, Yang S F. Influence of loosely bound extracellular polymeric substances (EPS) on the flocculation, sedimentation and dewaterability of activated sludge. Water Research, 2007, 41(5): 1022–1030

[32] Zhen G Y, Yan X F, Zhou H Y, Chen H, Zhao T T, Zhao Y C. Effects of calcined aluminum salts on the advanced dewatering and solidification/stabilization of sewage sludge. Journal of Environmental Sciences-China, 2011, 23(7): 1225–1232

Acknowledgements

This work was financially supported by Science and Technology Commission of Shanghai Municipality (Nos. 08 DZ 1202802, 09 DZ 1204105 and 09 DZ 2251700), the National Natural Science Foundation of China (Grant No. 51008322), China Scholarship Council (CSC) and Fundamental Research Funds for the Central Universities (No. 0400219152).

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg