On a local and global scale, wastewater collection and treatment plants are significant 
energy consumers and have a major impact on the environment and economy of many 
municipalities. Decentralization looks to be a promising option to address the sustainability issues 
of wastewater management systems since it focuses on on-site wastewater treatment as well as 
local recycling and reuse of domestic wastewater resources. In addition, Blackwater (BW) and 
Kitchen Refuse (KR) are household wastes with a high organic content that can be used as 
substrates for anaerobic co-digestion processes to recover biogas as a source of energy.
The research objective was to analyze a source separation decentralized BW and KR 
treatment system in which the energy is recovered from BW and KR co-digestion and digestate
gasification. The coupling of biological and thermal technologies allows for the complete 
conversion of wastes into energy and biochar, eliminating sludge disposal. 
A simplified anaerobic digestion model was developed and implemented to simulate the
biogas production potential. The simulation is based on a mathematical model using biomass, 
organic substrate, and biogas mass balances. The model was implemented in the INSEL simulation 
environment, and experimental data from the literature was used for validation. The results of the 
simulation match the experimental data well. Using the model, the energy consumption and 
generation potential of anaerobic co-digestion of BW and KR were assessed. 
Moreover, a greywater reuse system was investigated considering the same number of 
residents within an eco-district. It could be shown that conventional WWT systems require more 
energy and lead to more CO2 emissions than the greywater reuse system.