As already identified as a serious environmental problem in several regions of Europe, China, Russia and US, pig manure management has become a social and environmental problem nowadays that critically demands a definitive solution in the pig farming sector. It could be said that there are two main factors which have led to this situation during the last decades: i) the number of confined animals has increased where the largest farms are located, resulting in more manure produced than can be assimilated by the available farmland where the pigs are produced, and ii) stricter European/National directives have limited ground disposal of manure as fertilizer, which used to be the traditional solution in the past, due to nitrification of the land.
As a consequence, pig installations owners must pay to waste treatment companies for their pig slurry management (3-3.5 €/m3, which transportation costs accounts up to 60% of total) or alternatively, largest installations invest in their own treatment equipment to comply with these regulations.
During recent decades, the negative environmental impacts of livestock production and manure handling have been controlled by stricter regulations for manure storage and spreading. However, the intensification of livestock production has led to larger herds on fewer farms and industrial scale operations that produce large quantities of manure at centralised locations. As intensive livestock farming is being placed under increasing pressure to minimise the environmental impact of its operations several number of processes have been assessed as Best Available Technologies (BAT) for manure treatment while at the same time improving utilisation of the nutrient resources. However, most of the state-of-the-art solutions (SoA) are neither technologically, nor economically viable nowadays, and the most important fact, they are usually subjected to national subsidies to be profitable. EUROGAN is based in Spain (one of the largest pig producer and exporter countries worldwide) and have been active in the livestock sector since 1964. Our company, moved by real customer demand and aiming to exploit pig slurry business potential, has recently patented an innovative manure treatment process that accomplishes: 1. The concentration of contaminants in the manure (nitrogen, phosphorous, metals, bacteria, virus…) is minimized. 2. Treating the pig slurry at its origin 3. Its technical and economic viable for the farmer, being independent from national subsidies. 4. valorizes the manure (energy recovery and fertilizer).
The DEPURGAN project aims to bring to the market an efficient pig manure treatment process, with an initial investment 4 times lower compared to other solutions and operation costs being also very competitive. It base its innovative character in the use of an optimized electrocoagulation reactor, that allows nitrogen abatement, while producing as residues a solid fraction that poses great calorific potential as biomass, and a NPK liquid effluent ready to be used as fertilizer.
DEPURGAN will have a treatment capacity of 20 m3/h and includes a combination of: i) Solid/liquid separation applied with centrifuge, ii) High efficiency Electrocoagulation iii) final synthesis of fertilizer and biomass pelletizing. The system will be introduced in the pig farming sector as an all-in-one-solution, which will treat the manure at its origin, abate the contaminants in the liquid fraction providing an odorless and colorless liquid phase, and its economic viability will be independent from national subsidies.
The electrocoagulation is similar to a physicochemical treatment, but using electrical energy flowing through the medium instead of other mechanical or chemical agents, thus it has been defined as an electrochemical process. The pH increase at the cathode, promoting the formation of insoluble hydroxides (Al(OH)3, Fe(OH)3) that precipitate, trapping solid particles and organic material that form floccules, which are continuously extracted from the system. In parallel, different physic-chemical processes take place within the reactor that remove contaminants: ionisation, precipitation, emulsion breaking, electrolysis, free radical formation, compounds breaking and emulsion separation. The electrical discharge, together with strong oxidative radicals, as well as high pH, produce a biocide effect that also destroys the pathogens in the electrolytic cell.
The outputs of the system could be both commercialized: The liquid fraction can be used for fertirrigation. The solid fraction separated, which is about 5-10% of total pig slurry treated, can be converted to dried pelletized biomass to be used in the installation for central heating system, or as a saleable product.
