Ahmad, T., Ahmad, K., Alam, M. 2016. Sustainable management of water treatment sludge through 3‘R’ concept. Journal of Cleaner Production, 124, 1-13.
Brémond, U., de Buyer, R., Steyer, J.-P., Bernet, N., Carrere, H. 2018. Biological pretreatments of biomass for improving biogas production: an overview from lab scale to full-scale. Renewable and Sustainable Energy Reviews, 90, 583-604.
Carrère, H., Dumas, C., Battimelli, A., Batstone, D.J., Delgenès, J.P., Steyer, J.P., Ferrer, I. 2010. Pretreatment methods to improve sludge anaerobic degradability: A review. Journal of Hazardous Materials, 183(1), 1-15.
Černe, M., Palčić, I., Pasković, I., Major, N., Romić, M., Filipović, V., Igrc, M.D., Perčin, A., Goreta Ban, S., Zorko, B., Vodenik, B., Glavič Cindro, D., Milačič, R., Heath, D.J., Ban, D. 2019. The effect of stabilization on the utilization of municipal sewage sludge as a soil amendment. Waste Management, 94, 27-38.
Chanaka Udayanga, W.D., Veksha, A., Giannis, A., Lisak, G., Lim, T.-T. 2019. Effects of sewage sludge organic and inorganic constituents on the properties of pyrolysis products. Energy Conversion and Management, 196, 1410-1419.
Chen, J., Tyagi, R.D., Li, J., Zhang, X., Drogui, P., Sun, F. 2018. Economic assessment of biodiesel production from wastewater sludge. Bioresource Technology, 253, 41-48.
Chen, J., Zhang, X., Yan, S., Tyagi, R.D., Drogui, P. 2017. Lipid production from fed-batch fermentation of crude glycerol directed by the kinetic study of batch fermentations. Fuel, 209, 1-9.
Demirel F., Germec M., Coban B. H., Turhan I. (2018). Optimization of dilute acid pretreatment of barley husk and oat husk and determination of their chemical composition. Cellulose, 25, 6377-6393.
Ekblad, M., Falås, P., El-taliawy, H., Nilsson, F., Bester, K., Hagman, M., Cimbritz, M. 2019. Is dissolved COD a suitable design parameter for ozone oxidation of organic micropollutants in wastewater? Science of The Total Environment, 658, 449-456.
Elalami D., Carrere H., Monlau F., Abdelouahdi K., Oukarroum A., Barakat A. 2019. Pretreatment and co-digestion of wastewater sludge for biogas production: Recent research advances and trends. Renewable and Sustainable Energy Reviews, 114, 109287.
Geng, Y., Zhang, B., Du, L., Tang, Z., Li, Q., Zhou, Z., Yin, X. 2016. Improving methane production during the anaerobic digestion of waste activated sludge: Cao-ultrasonic pretreatment and using different seed sludges. Procedia Environmental Sciences, 31, 743-752.
Germec M., Demirel F., Tas N., Ozcan A., Yilmazer C., Onuk Z., and Turhan I. (2017). Microwave-assisted dilute acid pretreatment of different agricultural bioresources for fermentable sugar production. Cellulose, 24, 4337-4353.
Gherghel, A., Teodosiu, C., De Gisi, S. 2019. A review on wastewater sludge valorisation and its challenges in the context of circular economy. Journal of Cleaner Production, 228, 244-263.
Grobelak, A., Czerwińska, K., Murtaś, A. 2019. 7 - General considerations on sludge disposal, industrial and municipal sludge. in: Industrial and Municipal Sludge, (Eds.) M.N.V. Prasad, P.J. de Campos Favas, M. Vithanage, S.V. Mohan, Butterworth-Heinemann, pp. 135-153.
Grönroos, A., Kyllönen, H., Korpijärvi, K., Pirkonen, P., Paavola, T., Jokela, J., Rintala, J. 2005. Ultrasound assisted method to increase soluble chemical oxygen demand (SCOD) of sewage sludge for digestion. Ultrasonics Sonochemistry, 12, 115-120.
Gupta, N., Khare, P., Singh, D.P. 2019. Nitrogen-dependent metabolic regulation of lipid production in microalga Scenedesmus vacuolatus. Ecotoxicology and Environmental Safety, 174, 706-713.
Harris, P.W., McCabe, B.K. 2015. Review of pre-treatments used in anaerobic digestion and their potential application in high-fat cattle slaughterhouse wastewater. Applied Energy, 155, 560-575.
Juanssilfero A.B., Kahar P., Amza R.L., Miyamoto N., Otsuka H., Matsumoto H., Kihira C., Thontowi A., Yopi, Ogino C., Prasetya B., Kondo A. 2018. Effect of inoculum size on single-cell oil production from glucose and xylose using oleaginous yeast Lipomyces starkeyi, Journal of Bioscience and Bioengineering, 125, 695-702.
Kavitha, S., Jessin Brindha, G.M., Sally Gloriana, A., Rajashankar, K., Yeom, I.T., Rajesh Banu, J. 2016. Enhancement of aerobic biodegradability potential of municipal waste activated sludge by ultrasonic aided bacterial disintegration. Bioresource Technology, 200, 161-169.
Kidak, R., Wilhelm, A.-M., Delmas, H. 2009. Effect of process parameters on the energy requirement in ultrasonical treatment of waste sludge. Chemical Engineering and Processing: Process Intensification, 48(8), 1346-1352.
Kim, D.-H., Cho, S.-K., Lee, M.-K., Kim, M.-S. 2013. Increased solubilization of excess sludge does not always result in enhanced anaerobic digestion efficiency. Bioresource Technology, 143, 660-664.
Kor-Bicakci, G., Eskicioglu, C. 2019. Recent developments on thermal municipal sludge pretreatment technologies for enhanced anaerobic digestion. Renewable and Sustainable Energy Reviews, 110, 423-443.
Law S., Halim R., Scales P.J., Martin G. 2018. Conversion and recovery of saponifiable lipids from microalgae using a nonpolar solvent via lipase-assisted extraction, Bioresource Technology, 260, 338-347.
Li, X., Peng, Y., He, Y., Jia, F., Wang, S., Guo, S. 2016. Applying low frequency ultrasound on different biological nitrogen activated sludge types: An analysis of particle size reduction, soluble chemical oxygen demand (SCOD) and ammonia release. International Biodeterioration & Biodegradation, 112, 42-50.
Liu J., Mu T., He W., He T., Lu L., Peng K., Huang X. 2019. Integration of coagulation, acid separation and struvite precipitation as fermentation medium conditioning methods to enhance microbial lipid production from dewatered sludge. Bioresource Technology Reports, 7, 100221.
Liu, Y., Gao, M., Zhang, A., Liu, Z. 2017. Strengthen effects of dominant strains on aerobic digestion and stabilization of the residual sludge. Bioresource Technology, 235, 202-210.
Liu Y.Q., Nilsen P.J., Maulidiany N.D. 2019. Thermal pretreatment to enhance biogas production of waste aerobic granular sludge with and without calcium phosphate precipitates, Chemosphere, 234, 725-732.
Lizama, A.C., Figueiras, C.C., Pedreguera, A.Z., Ruiz Espinoza, J.E. 2018. Effect of ultrasonic pretreatment on the semicontinuous anaerobic digestion of waste activated sludge with increasing loading rates. International Biodeterioration & Biodegradation, 130, 32-39.
Ma, H., Zhang, S., Lu, X., Xi, B., Guo, X., Wang, H., Duan, J. 2012. Excess sludge reduction using pilot-scale lysis-cryptic growth system integrated ultrasonic/alkaline disintegration and hydrolysis/acidogenesis pretreatment. Bioresource Technology, 116, 441-447.
Mehrdadi, N., Kootenaei, F.G. 2018. An investigation on effect of ultrasound waves on sludge treatment. Energy Procedia, 153, 325-329.
Mikulski D., Kłosowski G., Menka A., Koim-Puchowska B. 2019. Microwave-assisted pretreatment of maize distillery stillage with the use of dilute sulfuric acid in the production of cellulosic ethanol. Bioresource Technology, 278, 318-328.
Mirmasoumi S., Ebrahimi S., Saray R.K., 2018. Enhancement of biogas production from sewage sludge in a wastewater treatment plant: Evaluation of pretreatment techniques and co-digestion under mesophilic and thermophilic conditions. Energy, 157, 707-717.
Niu, Q., Xu, Q., Wang, Y., Wang, D., Liu, X., Liu, Y., Wang, Q., Ni, B.-J., Yang, Q., Li, X., Li, H. 2019. Enhanced hydrogen accumulation from waste activated sludge by combining ultrasonic and free nitrous acid pretreatment: Performance, mechanism, and implication. Bioresource Technology, 285, 121363.
Paolini, V., Petracchini, F., Carnevale, M., Gallucci, F., Perilli, M., Esposito, G., Segreto, M., Occulti, L.G., Scaglione, D., Ianniello, A., Frattoni, M. 2018. Characterisation and cleaning of biogas from sewage sludge for biomethane production. Journal of Environmental Management, 217, 288-296.
Pei, J., Yao, H., Wang, H., Shan, D., Jiang, Y., Ma, L., Yu, X. 2015. Effect of ultrasonic and ozone pre-treatments on pharmaceutical waste activated sludge's solubilisation, reduction, anaerobic biodegradability and acute biological toxicity. Bioresource Technology, 192, 418-423.
Pilli, S., Bhunia, P., Yan, S., LeBlanc, R.J., Tyagi, R.D., Surampalli, R.Y. 2011. Ultrasonic pretreatment of sludge: A review. Ultrasonics Sonochemistry, 18(1), 1-18.
Pilli, S., Yan, S., Tyagi, R.D., Surampalli, R.Y. 2015. Overview of Fenton pre-treatment of sludge aiming to enhance anaerobic digestion. Reviews in Environmental Science and Bio/Technology, 14(3), 453-472.
Qian, L., Wang, S., Xu, D., Guo, Y., Tang, X., Wang, L. 2016. Treatment of municipal sewage sludge in supercritical water: A review. Water Research, 89, 118-131.
Raheem, A., Sikarwar, V.S., He, J., Dastyar, W., Dionysiou, D.D., Wang, W., Zhao, M. 2018. Opportunities and challenges in sustainable treatment and resource reuse of sewage sludge: A review. Chemical Engineering Journal, 337, 616-641.
Revellame, E.D., Hernandez, R., French, W.T., Holmes, W.E., Forks, A., Callahan Ii, R. 2013. Lipid-enhancement of activated sludges obtained from conventional activated sludge and oxidation ditch processes. Bioresource Technology, 148, 487-493.
Rodriguez, C., Alaswad, A., Mooney, J., Prescott, T., Olabi, A.G. 2015. Pre-treatment techniques used for anaerobic digestion of algae. Fuel Processing Technology, 138, 765-779.
Selvakumar P., Sivashanmugam P. 2017. Thermo-chemo-sonic pre-digestion of waste activated sludge for yeast cultivation to extract lipids for biodiesel production. Journal of Environmental Management, 198, 90-98.
Shao, L., Wang, T., Li, T., Lü, F., He, P. 2013. Comparison of sludge digestion under aerobic and anaerobic conditions with a focus on the degradation of proteins at mesophilic temperature. Bioresource Technology, 140, 131-137.
Shin, D.-c., Kim, J.-s., Park, C.-h. 2019. Study on physical and chemical characteristics of microorganism immobilized media for advanced wastewater treatment. Journal of Water Process Engineering, 29, 100784.
Siddiquee, M.N., Rohani, S. 2011. Experimental analysis of lipid extraction and biodiesel production from wastewater sludge. Fuel Processing Technology, 92, 2241-2251.
Toutian V., Barjenbruch M., Loderer C., Remy C. 2020. Pilot study of thermal alkaline pretreatment of waste activated sludge: Seasonal effects on anaerobic digestion and impact on dewaterability and refractory COD. Water Research, 182, 115910.
Wang D., Wang Y., Liu X., Xu Q., Yang Q., Li X., Zhang Y., Liu Y., Wang Q., Ni B.-J., Li H. 2019. Heat pretreatment assists free ammonia to enhance hydrogen production from waste activated sludge. Bioresource Technology, 283, 316-325.
Wang, F., Wang, Y., Ji, M. 2005. Mechanisms and kinetics models for ultrasonic waste activated sludge disintegration. Journal of Hazardous Materials, 123(1), 145-150.
Wang, Q. 2016. Achieving stable nitritation for mainstream deammonification by combining free nitrous acid-based sludge treatment and oxygen limitation. Scientific Reports, 6, 25547.
Wang, Z., Wang, B., Gong, X., Qiao, X., Peng, Y. 2019. Free nitrous acid pretreatment of sludge to achieve nitritation: The effect of sludge concentration. Bioresource Technology, 285, 121358.
Yang, G., Zhang, G., Wang, H. 2015. Current state of sludge production, management, treatment and disposal in China. Water Research, 78, 60-73.
Youssef E.A., Nakhla G., Charpentier P.A. 2011. Oleic acid gasification over supported metal catalysts in supercritical water: hydrogen production and product distribution. International Journal of Hydrogen Energy, 36, 4830-4842.
Yu, G., Peng, H., Fu, Y., Yan, X., Du, C., Chen, H. 2019. Enhanced nitrogen removal of low C/N wastewater in constructed wetlands with co-immobilizing solid carbon source and denitrifying bacteria. Bioresource Technology, 280, 337-344.
Zemke-White W.L., Clements K.D., Harris P.J. 2000. Acid lysis of macroalgae by marine herbivorous fishes: effects of acid pH on cell wall porosity. Journal of Experimental Marine Biology and Ecology, 245, 57-68.
Zhang, G., Yang, J., Liu, H., Zhang, J. 2009. Sludge ozonation: Disintegration, supernatant changes and mechanisms. Bioresource Technology, 100(3), 1505-1509.
Zhang, Q., Hu, J., Lee, D.-J., Chang, Y., Lee, Y.-J. 2017. Sludge treatment: Current research trends. Bioresource Technology, 243, 1159-1172.
Zhang, X., Chen, J., Idossou, V., Tyagi, R.D., Li, J., Wang, H. 2018. Lipid accumulation from Trichosporon oleaginosus with co-fermentation of washed wastewater sludge and crude glycerol. Fuel, 226, 93-102.
Zhang, X., Yan, S., Tyagi, R.D., Drogui, P., Surampalli, R.Y. 2014a. Ultrasonication assisted lipid extraction from oleaginous microorganisms. Bioresource Technology, 158, 253-261.
Zhang, X., Yan, S., Tyagi, R.D., Surampalli, R., Valéro, J.R. 2014b. Wastewater sludge as raw material for microbial oils production. Applied Energy, 135, 192-201.
Zhang, X., Yan, S., Tyagi, R.D., Surampalli, R.Y. 2013. Energy balance and greenhouse gas emissions of biodiesel production from oil derived from wastewater and wastewater sludge. Renewable Energy, 55, 392-403.
Zhang, X., Yan, S., Tyagi, R.D., Surampalli, R.Y., Valéro, J.R. 2014c. Lipid production from Trichosporon oleaginosus cultivated with pre-treated secondary wastewater sludge. Fuel, 134, 274-282.
Zhiyan Consultancy Group, 2016. Forecast report on operation situation and development trend of domestic sewage treatment market in China during 2016-2022. https://www.chyxx.com/research/201607/432940.html (accessed on 10th Oct. 2020)
Zhu, F., Wu, X., Zhao, L., Liu, X., Qi, J., Wang, X., Wang, J. 2017. Lipid profiling in sewage sludge. Water Research, 116, 149-158.
Zinatizadeh A.A., Mirghorayshi M., Birgani P.M., Mohammadi, P., Ibrahim S. 2017. Influence of thermal and chemical pretreatment on structural stability of granular sludge for high-rate hydrogen production in an UASB bioreactor. International Journal of Hydrogen Energy, 42, 20512-20519.