Many factors can inhibit the biological performance of the biogas plant. The operator must be aware of the frequent one:
The effect of ammonia on digestion is influenced by temperature, inputs composition, pH and bacteria acclimation. The concentration should be kept under 2000 ppm for an optimal operation. However mesophilic digester can support more than 3000 ppm if they are well acclimate to ammonia. An excess of ammonia can cause digestion failure.
Anaerobic bacteria require very little oxygen in the environment you need below 0.1 ppm O2
The VFA concentration can off-balance the biology of the system and should me less than 2000 ppm
Salt accumulation can affect the digestion performance. Sodium concentration should be in the range 3500 to 5500 ppm
Trace concentrations of heavy metal is benefit for bacteria but high concentration can be toxic for the digestion.
Temperature should not vary more than 1 °C, if there are any changes in the temperature check the heating system and the PLC program.
If any problem in the program or alarm are found, ask for technical assistance to repair any PLC bug.
If a mixer or pump doesn’t work. Look in the user manual of the equipment for troubleshooting. Finally, ask for a technical assistance to repair any parts.
|Most likely causes||
|Gas yield has dropped||
|Methane concentration dropped||
|FOS/TAC ratio has increased||