The less water the better
There are 3 systems for pig manure removal and pig keeping: self-flow, hydro-flush and cold-keeping.
Other names for self-flow pig manure removal system are slot floor/bath with cork system, Danish or Spanish system.
Self-flow (cork / slot floor)
Adding water to pig manure 1:1-2. Pig manure is accumulated in a bath with a cork which is removed once every 1-3 weeks. Self-flow is ideal for biogas production. New pig farms mainly use the self-flow system.
Adding water to manure 1:10. Pig manure is washed off constantly. The system is mainly used on old 100,000-head pig farms. Biogas reactors using wastewater are very large. The organic load in the reactor is very low. The biogas plants can be built only for a part of manure, the separated fraction. Hydro-flush is often confused with a self-flow.
Pigs are kept in tent hangars constantly on deep bedding. Pig manure is removed only once after slaughter. With this method, a biogas plant does not make sense due to the fact that most gas having left the manure over 5 months. And high bedding content creates difficulties when mixing substrates in reactors.
Systems for pig keeping
Zorg Biogas has built several biogas plants for pig farms. Examples are a biogas plant, 125 kW, for a pig reproduction farm with 1,500 sows Demis-Agro Ltd (Podgorodnoe, Ukraine). In Podgorodnoye, oil from chips and confectionery waste are added to the pig manure.
A biogas plant, 635 kW, for a full-cycle pig farm Porco-Bela Ltd (Cimiseni, Moldova). Her slaughter house waste are added.
To calculate a quotation for a biogas plant, please fill out the questionnaire for pig farms.