Язык . Language


Technical maintenance of a biogas plant consists of tasks that are necessary for its long useful life, and repair works are carried out in cases of breakage of the biogas plant.

Table 15. Daily technical maintenance [8]

Сontrol Mistakes Removal
gas pressure gas pressure too high;
gas pressure rises, if gas
consumption is lower than the
production and if the gas storage
The pressure relief valve
malfunctions – it should be
cleaned or renewed;
gas pressure too low;
(gas pressure falls,
if the consumption
(including leakage!)
is higher than the
production and if
the gas storage is
leakage in gas conducting
parts: find out the leakage
and seal;
temperature too high; defective heating control
system. Check control
system and repair or
exchange part(s)
temperature too low; defective heating control
system. Check control
system and other concerned
part(s), repair or exchange;
sediment layer on the
heating surface: remove
gas production gas production clearly
under normal
biological reasons:
temperature, substrate,
antibiotics, change of pHvalue;
leakage in digester or piping
system; blocked gas pipes
due to water or alien
identify problem and act
strong sludge odor plant is overloaded or
fermenting conditions are suboptimal;
reduce substrate intake;
correct pH-value with
adequate means;

Weekly/monthly (prophylactic) maintenance work• clean gas appliances;
• lubricate movable parts (slides, guiding frame of floating drum plants, taps etc.);
• servicing of biogas-driven engines within the prescribed time intervals;
• maintenance of pressure relief valves and under pressure valves;
• maintenance of slurry agitator / mixer;
• control gas appliances and fittings on tightness and function.

Table 16. Control of functions [8]

Сontrol Mistakes Removal
water separator water separator is
empty water separator;
piping system no water is collected
in the water
gradient of the pipes is
reinstall pipes in a way that
condensation flow leads to the
water separator;
pressure relief and
under pressure
valves non-functioning
clean valves or renew them

Annual maintenance work
• Complete check of digester and the whole plant;
• Check the plant in respect of corrosion and, if necessary, renew protective coating material;
• Check the gas pipes for gas tightness (pressure check). If necessary, search the leakage and repair the parts concerned. Minor gas leakage is usually undetected during normal operation as it is ’compensated’ by gas production

Monitoring presumes collection of data about operation of biogas plant for:
• determining operational problems;
• determining real economical profitability and payback period of the biogas plant;
• comparison of different substrates and operation methods for optimisation.

The following data should be gathered:
• Quantity and type of substrate, water proportion of diluting substrate.
• Temperature of substrate on different stages of digestion process. When this data is collected regularly the defects on the heating system can be easily determined and prevented.
• Biogas production: the volume of biogas produced is measured by a gas meter located between digester and gas holder and measures of biogas consumed by appliances by gas meter located between appliance and gas holder. In simple plants biogas production can be measured at the time of absence of biogas consumption. Changes in gas production and the speed of these changes allow for a more exact determination of causes of arising problems.
• Electricity and heat production in big plants.
• pH ratio (monthly).
• Daily substrate input portion.
• Hydrogen sulphide content of biogas (monthly).
• Analysis of fertilizing effect of digested sludge (yearly or seasonally) for determining optimal fertilizer quantity to be applied to soil.
• Records of breakages and their causes. Having such records allows comparison of breakages and easier determination of their causes.