Towards Energy Efficient Onsite Wastewater Treatment

Renata Mirra, Christian Ribarov, Dobril Valchev, Irina Ribarova


The objective of this work is to demonstrate that some weaknesses of the onsite packaged WWTP associated with high operational costs and energy inefficiency could be overcome by improved management. The research methodology consists of series of batch studies with sludge from municipal or onsite WWTP, which simulate different working regimes of the onsite WWTPs – daily operation, toilet flushing and dishwasher machine. A simple classical tool, Oxygen Uptake Rate (OUR) is used to prove the hypothesis that regardless the specificity of the onsite WWTPs, namely the irregularity of the flow and load, three parameters follow similar increasing and decreasing trends – inflow rate, inflow pollution load and oxygen demand in the reactor. The literature review has not shown research publication about applicability of (OUR) for management of onsite WWTPs, but has shown experience and knowledge with municipal WWTPs, which were utilized in our study. The results prove that when there is no wastewater generation in the household, the (OUR) in the reactor is very low, 0.0007 to 0.0015 mg/l.s, thus do not require high oxygen supply. However, when wastewater flushes into the onsite WWTP, the oxygen demand increases rapidly and (OUR) reaches the range of 0.0040 to 0.0063 mg/l.s depending on the type and the quantity of the incoming substrate (pollution load). These results, if verified in filed experiments will enable optimization of the energy use during onsite WWTP operation.  The suggestion is that the oxygen supply in the reactor should be adjusted according to the demand, respectively proportional to the inflow rate. In addition to the benefit of saving energy, the comprehensive sensors for dissolved oxygen monitoring, which require qualified maintenance could be avoided and replaced by simple sensors for level, which are anyway part of the equipment of most of the onsite packaged WWTP.


Decentralized Wastewater Management; Individual or Other Appropriate Systems (IAS); Onsite Wastewater Treatment; Oxygen Uptake Rate (OUR); Energy Efficiency.


Sands, Philippe, and Paolo Galizzi, eds. “Council Directive 91/271/EEC of 21 May 1991 Concerning Urban Waste Water Treatment (OJ L 135 30.05.1991 P. 40).” Documents in European Community Environmental Law (1991): 851–864. doi:10.1017/cbo9780511610851.054.

Diaz-Elsayed, N., Xiaofan, X., Balaguer-Barbosa, M. & Zhang, Q. “An evaluation of the sustainability of onsite wastewater treatment systems for nutrient management”. Water Research, (2017): 121, 186-196. doi:10.1016/j.watres.2017.05.005.

Dubois V., Boutin, C. Comparison of the design criteria of 141 onsite wastewater treatment systems available on the French market. J Environ Manage, (2018), 216:299-304. doi:10.1016/j.jenvman.2017.07.063.

Moelants, N., Janssen, G., Smets, I. & Van Impe J. “Characterisation and optimisation of individual wastewater treatment systems”. Water Science & Technology, (2008a): 57(12), 2059–2064. doi:10.2166/wst.2008.324.

Moelants, N., Janssen, G., Smets, I. & Van Impe J. “Field performance assessment of onsite individual wastewater treatment systems”. Water Science & Technology, (2008b): 58(1), 1-6. doi:10.2166/wst.2008.325.

Furrer, V. Remote Monitoring of On-Site Wastewater Treatment Plants by Means of Low-Maintenance Sensors Data Collection and Interpretation from a SBR in Operation, MSc thesis, 2018. doi:10.3929/ethz-b-000333560.

Schneider, M., Y., Carbajal, J., P., Furrer, V., Sterkele, B., Maurer, M., Villez, K., Beyond signal quality: The value of unmaintained pH, dissolved oxygen, and oxidation-reduction potential sensors for remote performance monitoring of on-site sequencing batch reactors, Water research, (2019): Volume 161, 639-651. doi:10.1016/j.watres.2019.06.007.

Jakubaszek, A. and Stadnik, A., Technical and technological analysis of individual wastewater treatment systems, Civil and environmental engineering reports, 2018, 28 (1), 087-099. doi:10.2478/ceer-2018-0008.

Spanjers, H., Vanrolleghem P.A., Olsson, G. & Dold, P. “Respirometry in control of the activated sludge process”. Water Science & Technology, (1996): 34(3-4), 117-126. doi:10.2166/wst.1996.0424.

Chandra, S., Mines, R.O. & Sherrard, J.H. “Evaluation of Oxygen Uptake Rate as an Activated Sludge Process Control Parameter”. Journal Water Pollution Control Federation, (1987): 59(12), 1009-1016. doi: 10.2307/25043430.

Kim, Jong Kyu, Michael Dooley, Min Hee Lee, and Jae Mee Lee. “Activated Sludge Process Diagnosis Using Advanced Real-Time Monitoring Equipment: Activated Sludge Plant Controller (ASP-CON).” Environmental Earth Sciences 78, no. 15 (July 19, 2019). doi:10.1007/s12665-019-8444-4.

Wastewater Treatment Plant Operator Certification Training, Module 16: The Activated Sludge Process Part II, Revised October (2014), Pennsylvania Department of Environmental Protection.

Baeza, J.A., Gabriel, D. & Lafuente, J. “In-line fast OUR (oxygen uptake rate) measurements for monitoring and control of WWTP”. Water Science and Technology, (2002): 45(4–5), 19–28. doi:10.2166/wst.2002.0541.

Pabitra, B. “Evaluation of toxicity of pharmaceuticals to the activated sludge treatment plant”. MSc thesis, Tampere University of Technology, (2010) Finland.

Ghosalker, A., and M. G. Kashid. "Oxygen Uptake Rate Measurement by modified dynamic method and effect of mass-transfer rates on growth of Pichia Stipitis: modeling and experimental data comparison." Austin J Biotechnol Bioeng 3, no. 3 (2016): 1-6.

Ochoa, F., Gomeza, E., Santosa, V. & Merchuk, J. “Oxygen uptake and oxygen transfer in bioreactor design”. Biochemical Engineering Journal, (2010): 49, 289-307.

Zou, X., Hang, H., Chu, J., Zhuang, Y. & Zhang, S. “Oxygen uptake rate optimization with nitrogen regulation for erythromycin production and scale-up from 50 L to 372 m3 scale”. Bioresour Technol., (2009): 100(3), 1406-12. doi: 10.1016/j.biortech.2008.09.017.

Hagman, M. & Jansen, J. “Oxygen uptake rate measurements for application at wastewater treatment plants”. VATTEN 63:131–138. Lund. (2007). Corpus ID: 108283854.

Standard Methods for the Examination of Water and Wastewater 2017 23th edn, American Public Health Association, Washington DC, USA. ISBN: 9780875532875.

Ziad, H. “Oxygen uptake rate as an extended aeration process control parameter”. Journal of Environmental Science and Health, Part A: Environmental Science and Engineering and Toxicology, (1995): 30(5), 951-969. doi:10.1080/10934529509376242.

Chalasani, Gautam, and Weimin Sun. "Measurement of temperature effects on oxygen uptake rate in activated sludge treatment." Report, Michigan State University College of Engineering, East Lansing, MI, USA (2007): 1-28.

Torretta, Vincenzo, Marco Ragazzi, Ettore Trulli, Giovanni De Feo, Giordano Urbini, Massimo Raboni, and Elena Rada. “Assessment of Biological Kinetics in a Conventional Municipal WWTP by Means of the Oxygen Uptake Rate Method.” Sustainability 6, no. 4 (April 9, 2014): 1833–1847. doi:10.3390/su6041833.

Arias-Navarro, Maria, Maria Villen-Guzman, Rocio Perez-Recuerda, and Jose M. Rodriguez-Maroto. “The Use of Respirometry as a Tool for the Diagnosis of Waste Water Treatment Plants. A Real Case Study in Southern Spain.” Journal of Water Process Engineering 29 (June 2019): 100791. doi:10.1016/j.jwpe.2019.100791.

Willetts, J., Fane, S. & Mitchell, C. “Making decentralized systems viable: a guide to managing decentralised assets and risks”. Water Sci. Technol., (2007): 55(5), 165–173. doi:10.2166/wst.2007.569.

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DOI: 10.28991/cej-2020-03091542


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