Sewage treatment plant assumes significant job in treating sewage water and decrease deficient water issues. This handling system is helpful for the public as it gives treated water and remaining slop utilized as compost. Plant administrators faced economic crises due to several reasons including high cost of electricity. To overcome this situation, plants switched to change sludge into biogas which may be used for creating power and that can be used to operate all the STP units. This power producing unit has six subsystems organized in a series configuration. Its performance has been examined by considering reliability, availability, maintainability, and dependability approach. All failure rates are exponentially distributed and statistically independent. By using Markovian birth–death procedure Chapman–Kolmogorov differential difference equations has been derived. Various measures of system effectiveness have been measured. The findings of the system model have also been discussed with system designers.