The main goal of the LIFE-OPTIMAL 2012 Project is the demonstration of an innovative approach for the handling of the manure produced by livestock farming.
The specific objectives of the project, in descending order, are the following:
Thanks to the implementation of this project the following concrete results can be achieved:
Specific aims of the project:
To achieve the objectives reported above, a ecological friendly systems in order to manage the digest (coming from traditional biogas plants) will be implemented. The powerplant feeded by manure of the dairy cattle farmers of the Wipptal will be put in operation on end of the year.
The digestate, produced by the system will in part be used for the fertilization of the fields (especially grassland) of the farmers taking part of the project. The existing biogas plant permits to solve the problem of the odour (spreading digestate instead of slurry or manure) and also to produce electricity and heat, which are sold, but does not solve the environmental problem of the excessive load of nutrients and ammoniac produced in the area.
The solution proposed is to annex to the biogas plant a digestate treatment plant, formed by the following sections: screw press separator, centrifuge separator (decanter), ultrafiltration unit, reserve osmosis, zeolite filter unit, ammonia stripping unit and drying and pelletting unit.
A solid one, obtained by separating the solid fraction of the digestate, that can be enriched with the concentrates from the ultrafiltration and reverse osmosis process in order to produce a “new fertilizer” with nutrient concentrations and proportions according to the requirements of the fertilized crops;
A liquid one, consisting in an ammonium sulphate solution, obtained from the ammonia coming from the ammonia stripping unit.
These products can be used for fertilization in the orchards and vineyards of South Tyrol.
At the partners’ farmsteads, some 25,000 tons of manure and 45,000 tons of slurry are collected with specific machinery for their transportation.
This manure is then treated using anaerobic digestion in the Wipptal biogas system, and the biogas produced there is transformed into electrical energy and heat.
Around half of the digestate produced is returned to the farmers and distributed over the land using a specifically made high-precision, low-emission prototype. The other half of the digestate undergoes mechanical separation using a spiral compression separator and a vibrating screen to separate the solid and liquid components of the digestate. The liquid part undergoes a three-stage reverse osmosis process that makes it possible to obtain purified water that can be discharged into a surface water body, together with a concentrate that is rich in nutrients for crops.
The solid part of the digestate is dehydrated using waste heat produced by the cogeneration group and subsequently turned into pellets to become fertiliser. The concentrates obtained from reverse osmosis can be used as such for fertilising crops or they can be added to pellets.
The purified water is discharged into the Eisack River.
The project aims to reduce the impact of slurry and manure from cows, using the following actions:
The main results achieved by the LIFE-OPTIMAL2012 project are summarised in the following points:
1) construction, start-up and running of the digestate treatment plant. This plant has been created in three main sections:
section one: digestate separation and concentration. Innovative section – able to treat slurry or the derivatives of same from both cattle and pigs, as well as digestate from various anaerobic digesters – the process of which is based on a series of mechanical separation and concentration treatments via reverse osmosis membrane, using a combination of the innovative, patented anti-soiling, vibrating membrane with spiral-wound membranes. Within this section, there is an initial process to separate the solids and liquids of the digestate: the solid fraction is the raw material that, once dried and transformed to pellets, becomes the base for the production of biwi Bio-Pellets, the solid fertiliser that is sold to reduce the nitrogen load from the agricultural area covered by the project. The remaining liquid fraction is further treated, allowing Biogas Wipptal to obtain purified water (permeate) that is suitable for discharging into surface water bodies, and also, a concentrate of nitrogen and phosphorus at a reduced volume of 40-45% compared to the initial liquid, which is then easy to transport, store or convert to fertiliser with a higher ammoniacal nitrogen and phosphorus content. This concentrate, which is also valid in the biological field, is used as liquid fertiliser. This section can treat up to a maximum of 160 tons of digestate per day, producing around 30 tons of purified water that can be discharged into the Eisack River, plus about some 55 tons of concentrate;
second section: drying of the solid fraction by means of an 8-level belt system which makes use of the excess heat (via hot air heat exchangers) from biogas cogeneration to dry up to a maximum of around 15 tons of incoming solids per day;
third section: formation of the dried material into pellets. The solids are dried in the form of pellets using a mill and pellet mill, on a line that is capable of processing up to six tons of incoming dried material per day.
2) Construction, testing and use of the prototype liquid manure spreader.
The prototype made by the associate beneficiary, Zunhammer, is equipped with a device to measure the nutritional elements of the digestate in real-time, a GPS position sensor, and an electronic system to control and regulate the dosage.
3) Gas, mass, and energy balances for the digestate treatment system. This activity, completed by the University of Turin, demonstrated the effectiveness of the digestate treatment system in terms of the efficiency of mass separation and the physical and chemical parameters. Overall consumption of thermal and electric energy (direct and indirect) identified and expressed as primary energy, are equivalent to 28.6*10-3 Tep/t of treated digestate and 55.7*10-4 Tep/kg of N contained in the pellet.
4) Production of solid pellet fertiliser called biwi Bio-Pellets, registration of same under no. 0021548/18 of the “National Fertilisers Register” and development of marketing products for retail to private customers, farming consortia, and various distribution chains. Based on types of national fertiliser as per Lgs. Decree no.75/2010, biwi Bio-Pellets is classified as an NP organic fertiliser (Annex 18.104.22.168) and is recommended for growing fruit, vegetables, and flowers;
5) Growing tests in pots (corn, cucumber, permanent pasture, strawberries) and in the field (vines) by the University of Bolzano-Bozen, show a positive effect (increase in surface biomass) above all for corn and cucumber;
6) printing and circulation of the “biwi Bio-Pellets user’s manual”, containing instructions for dosage based on the type of crop, degree of organic substance in the soil, and the period of application;
7) control sampling for the quality of the purified water discharged into the surface water flowing near to the Biogas Wipptal plant, i.e., into the Eisack River, with continued monitoring of the unloaded capacity, the pH, conductivity, and ammoniacal nitrogen, as well as the implementation of the whole automatic system for management of livestock waste, from when it enters the plant by electronic weighing, to its return to the field with new weighing and control of spreading.
8) Overall assessment of the digestate treatment system
From examinations made by the School of Agricultural, Forest and Food Sciences (DISAFA) of the University of Turin, it has been found that implementation of the technological solutions proposed has made it possible to:
The 2012 LIFE OPTIMAL project was completed in 2021. Nevertheless, we feel obligated to continue participating in the monitoring and communication activities and are very active in responsibly representing the E.U.’s LIFE Program.
The project partners continue to provide support to the company Biogas Wipptal, above all in terms of technical monitoring, as well as economic, environmental, and socio-economic support for the technical solutions completed.
Therefore, there will be data collection and processing operations, using the same data collection methods and assessment used during the project and with reference to all actions and expected results. The resulting reports will allow the consolidation of results obtained during the project and at the same time, implementation of the solutions proposed to achieve sustainability.
The project partners will also continue to provide support to the public authorities (European, national, and regional) for the transfer of the know-how acquired during monitoring and implementation.
The information and circulation activities will continue through the promotion of training courses and workshops, participation at national and international conferences, as well as participation at public events. The project website will remain active and constantly updated with information on subjects of interest and events. With the involvement of all partners, guided visits will be organised to promote increased knowledge of the management system proposed and the transferable nature of the technologies made as part of the LIFE-OPTIMAL2012 project.
Activities prior to the period of implementing the project will remain under the responsibility of Biogas Wipptal.
Currently, the BIOGAS Wipptal plant is undergoing extension and reconversion to upgrade the biogas and biomethane liquefaction for transport. The start of production for BioGNL for transport is envisaged for 2022.
The goals of the project funded by the E.U. in the framework of the LIFE+ Program were as follows:
The following concrete measures were implemented in the framework of the LIFE+ Program: