This PH and temperature measurement and control system is a complete biogas generation in a biodigester installation. Changes in temperature in the biogas digester result in changes in methane gas production. Methane gas production will increase if the temperature increases and PH is neutral.

The role of pH is related to media for microorganism activity. Anaerobic bacteria require optimal pH between 6.2 - 7.6, but the good is 6.6 - 7.5. Initially the media has a pH of ± 6 then rises to 7.5. The digestive tank can be said to be stable if the solution has a pH of 7.5 - 8.5. The lower limit of pH is 6.2, below that pH the solution is toxic, meaning that biogas-forming bacteria are not active. Controlling pH naturally is done by NH4 + and HCO3-ions. These ions will determine the pH

Likewise the air temperature and temperature in the digestive tank have a big contribution in producing biogas. Air temperature indirectly affects the temperature in the digestive tank, meaning that a decrease in air temperature will reduce the temperature in the digestive tank. The role of air temperature is related to the anaerobic decomposition process.

In order to determine the temperature and PH of the slurry solution in a continuous biogas digester, a Temperature Gauge and a PH Digester are used as well as this device as well as a processor that drives the submersible pump automatically and periodically.