4.3 Comparison of energy self-supply and biomethane production of sewage plants

In our case study, in order to quantify energy possibilities, we conducted our calculations for a nutrient-containing wastewater treatment plant using a anaerobic fermentation technology for a population equivalent of 100,000 inhabitants (equivalent to an adult inhabitant's wastewater), which was considered as average in Hungary. Based on our conception and data collection - which were partly promoted by the Higher Education Institutional Excellence Programme of the Ministry of Human Capacities in Hungary (No. 20428-3/2018/FEKUTSTRAT) - for the use of biogas produced during fermentation, we present two possibilities in this section:


Basic data of the 100,000 household equivalent wastewater plants:


Source: [49–51].

The amount of biogas generated by anaerobic technology, using the above (average) technological characteristics:

• 13,000 m3 \* 0.37 kWh/m3 = 1860 Nm3 /day.

Allowing for a 15% loss of biogas above, a biogas calorific value of 6.5 kWh/m3 and the energy consumed in energy production, and calculating using 60% heat and 40% electricity ratios, the quantity of the final product with the two technologies examined is shown below.
