The Enhancement of Energy Efficiency in a Wastewater Treatment Plant through Sustainable Biogas Use: Case Study from Poland

Abstract

The improvement of energy efficiency ensuring high nutrients removal is a great concern for many wastewater treatment plants (WWTPs). The energy balance of a WWTP can be improved through the application of highly efficient digestion or its intensification, e.g., through the introduction of the co-substrates with relatively high energy potential to the sewage sludge (SS). In the present study, the overview of the energetic aspect of the Polish WWTPs was presented. The evaluation of energy consumption at individual stages of wastewater treatment along with the possibilities of its increasing was performed. Additionally, the influence of co-digestion process implementation on the energy efficiency of a selected WWTP in Poland was investigated. The evaluation was carried out for a WWTP located in Iława. Both energetic and treatment efficiency were analyzed. The energy balance evaluation of this WWTP was also performed. The obtained results indicated that the WWTP in Iława produced on average 2.54 GWh per year (7.63 GWh of electricity in total) as a result of the co-digestion of sewage sludge with poultry processing waste. A single cubic meter of co-substrates fed to the digesters yielded an average of 25.6 ± 4.3 Nm3 of biogas (between 18.3 and 32.2 Nm3/m3). This enabled covering the energy demand of the plant to a very high degree, ranging from 93.0% to 99.8% (98.2% on average). Importantly, in the presence of the co-substrate, the removal efficiency of organic compounds was enhanced from 64% (mono-digestion) to 69–70%.

Biogas Production from Organic Wastes: Integrating Concepts of Circular Economy

“…Masłoń et al [69] reported the performance of co-digestion at the WWTP located in Iława (Poland) for a two-year period using as co-substrate poultry fat wastes. These authors observed an increase in biogas production of 82% with an enhancement of 29% in volatile solid removal.…”

Scenario Analysis for Selecting Sewage Sludge-to-Energy/Matter Recovery Processes

“…The anaerobic digestion process is usually operated in the mesophilic temperature range (35-40 • C) while the action of methanogens bacteria well performs in the pH range 6.8-7.2 [28]. Biogas production per unit mass of volatile solid substance can vary in a wide range of values: for a sludge with 75% of volatile solid and a digestion process time of 21-25 days a specific biogas production of 0.6-0.8 (Nm 3 /kg) of volatile solid can be obtained [8]. Performance measures indexes measuring the efficiency in sludge-to-biogas conversion highly depends on type of sludge.…”

“…The SS production rate generated from WWT is growing day by day as the water demand, and, thus, the amount of wastewater produced, is on increase [8]. The rapid increase depends on two main factors.…”

The Effect of Bioaugmentation Strategy on the SBR Performance Treating Reject Water and Municipal Wastewater under Various Temperature Conditions

“…Currently, the leading challenge for municipal wastewater treatment plants (WWTPs) staff is to ensure both a high-quality effluent wastewater and reduction of operating costs [Shahzad et al, 2015;Drewnowski et al, 2019;Masłoń et al, 2020]. In particular, large facilities must meet stringent requirements with regard to nitrogen and phosphorus for wastewater discharge to the environment [Mucha and Mikosz, 2021; Jaromin-Gleń et al, 2013; Barbusiński et al, 2020].…”

“…In particular, large facilities must meet stringent requirements with regard to nitrogen and phosphorus for wastewater discharge to the environment [Mucha and Mikosz, 2021; Jaromin-Gleń et al, 2013; Barbusiński et al, 2020]. Therefore, advanced treatment technologies should be applied [Roots et al 2020;Shourjehet al, 2020;Czarnota et al, 2020]. It is noteworthy that WWTPs aremodern facilities with high energy consumption, while the treatment process itself is multi-stage and complicated [Zubrowska-Sudol et al, 2018; Kudlek and Dudziak, 2018; Szeląg and Barbusinski 2020], so the additional method of monitoring and control are developed [Guz et al, 2015;Łagód et al, 2019;Byliński et al, 2019].…”