Monitoring and diagnosis of energy consumption in wastewater treatment plants. A state of the art and proposals for improvement

Abstract

In response to strong growth in energy intensive wastewater treatment, public agencies and industry began to explore and implement measures to ensure achievement of the targets indicated in the 2020 Climate and Energy Package. However, in the absence of fundamental and globally recognized approach evaluating wastewater treatment plant (WWTP) energy performance, these policies could be economically wasteful.This paper gives an overview of the literature of WWTP energy-use performance and of the state of the art methods for energy benchmarking. The literature review revealed three main benchmarking approaches: normalization, statistical techniques and programming techniques, and advantages and disadvantages were identified for each one. While these methods can be used for comparison, the diagnosis of the energy performance remains an unsolved issue. Besides, a large dataset of WWTP energy consumption data, together with the methods for synthesizing the information, are presented and discussed. It was found that no single key performance indicators (KPIs) used to characterize the energy performance could be used universally. The assessment of a large data sample provided some evidence about the effect of the plant size, dilution factor and flowrate. The technology choice, plant layout and country of location were seen as important elements that contributed to the large variability observed.

Energy consumption modeling during dairy sewage pretreatment

“…It was also proven by the analysis of 601 wastewater treatment plants conducted by Longo et al [3] in which the achieved percentage share of pretreatment in the total energy consumption ranged between 5 and 18%. The authors of the research conducted in Irish municipal wastewater treatment plants report this value at 1.8-9.1% [4].…”

Comparative Analysis of the Energy Consumption of Different Wastewater Treatment Plants

“…In Germany and Italy, about 1% of the country's energy consumption is in the WWTPs, which is a good estimate for the European countries [25], although other percentages may be described in the literature. Reference [3] cited 0.7% for Germany, 0.6% for the United States and 0.25% for China.…”

“…The sludge treatment, until its final disposal, can consume between 0.074 and 0.15 kWh/m 3 due to the different forms of management. If an aerobic treatment is applied, the consumption is compared to the one of the aeration system [25]. On the other hand, bio-drying is a process that uses the heat produced by microorganisms [35].…”

“…Reference [17] estimated consumption at 0.09 kWh/m 3 in India, or 45.3% of the total used for the WWTP operation. In the USA, the expenditure at this stage is 0.04 kWh/m 3 , in New Zealand it varies between 0.04 and 0.19 kWh / m 3 , in Canada it is around 0.02 and 0.1 kWh/m 3 [24], in Hungary it is between 0.045 and 0.14 kWh/m 3 , and in Australia it is estimated to be between 0.1 and 0.37 kWh/m 3 [21,25] suggested a global consumption average of 5 to 18% for pumping.…”

“…Reference [25] presented a review of the literature on energy consumption in WWTPs from countries in North America, Asia and Europe. So, the preliminary treatment consumes less than 1% of the total consumed in the WWTP.…”