Biomethane. Giving food waste a second life
The article published in the February issue of “Macchine Alimentari” magazine
From waste to green energy: how food industry by-products becomes a resource that blends environmental and economic sustainability.
Food industry by-products, mainly from the processing of raw materials with a high degree of biodegradability, are now an incredible opportunity to produce renewable energy and promote circular and sustainable economies.
The most significant waste from the agro-food industry comes from meat and fish processing, dairy and confectionery by-products, fruit and vegetable residues, cereals and tubers. Together with wastewater, with the right technologies, these substances can be valorised and transformed into biomethane. For food industries, which can also benefit from the opportunity to use it for out-of-date and returned products, it is one of the technological solutions that best reconciles environmental and economic sustainability.
Producers can feed biomethane directly into the national grid or use it as a green biofuel for product handling fleets, reducing the carbon footprint – the impact of activities on the Global Climate in terms of amount of CO2 that processes generate throughout the life cycle of products – and benefiting from the incentives provided by national legislation.
IES Biogas solutions and technologies for the Food Industry
One of the most prominent companies in the construction and management of biogas and biomethane plants at international level is IES Biogas. The company, which is part of the Snam group, one of the largest operators of energy infrastructures in the world, has set up an entire division, IES Food Industry, dedicated to the Food & Beverage industry: considering the extreme variability of the production processes specific to this sector, it is thus qualified to offer the best technological solutions for optimising the production of biogas from any organic matrix with suitable potential, through an in-depth assessment of the industry and the territorial context where it operates.
Among the technological solutions proposed, the implementation of robust, reliable and flexible CSTR (Continuous Stirred Tank Reactor) is suitable for solid and semi-solid matrices. For liquid matrices with a high organic load, on the other hand, the use of “fast” anaerobic systems such as UASB/EGSB fluidised bed reactors, characterised by high efficiencies in terms of biogas production, reduced organic loads, low hydraulic residence times and small volumes, can maximise biogas production with a consequent reduction in organic load.
For processing high nitrogen digestates and streams, IES Biogas offers a deammonification process, an efficient ammonia removal system using autotrophic microorganisms, which reduces volumes and energy consumption.
Completing the portfolio of biological systems are the aerobic technologies for the subsequent treatment and refinement of wastewater with SBR (discontinuous sequential process) and MBR (membrane reactors) technologies, which guarantee a further reduction in organic load. Among the final systems, ultra-filtration and reverse osmosis processes are recommended for water recovery, with a view to minimising water consumption with a dedicated approach to ZLD (Zero Liquid Discharge).
As for biogas, IES Food Industry also uses the best plant solutions for treatment and subsequent upgrading, with the focus on maximising yields and feeding the maximum volume of biomethane available into the grid.
In the food industry context, regardless of biomethane production, all the solutions proposed always lead to high energy efficiency targets and minimise operating costs, through the reduction of sludge produced and chemicals used.
Every plant we build,” explains Marco Mazzero, CEO of IES Biogas, ” fulfils the needs of the market in terms of construction and safety, management and automation. The architectural and executive design, the piping, the electrical and hydraulic systems, and the software are entirely developed in-house, guaranteeing the customer a truly customised quality product”.
In Amiens, France, IES Biogas is starting the modernisation of the Idex Environnement Picardie plant: the new line will treat 20,000 tonnes/year of waste from retail and catering to obtain 2.2 million m3 of biogas and an annual electricity production of 6 million kWh. In the overall upgrading project (€ 20 million), the company will focus on waste pre-treatment with depackaging, pasteurisation with regenerative system, anaerobic digestion and digestate separation.
Back in Italy, IES Biogas has created several outstanding examples of circular economy: in Sicily, the Assoro plant, which produces 4,400 Sm3 of biomethane from agro-industrial waste, including citrus processing waste and olive pomace, is able to fuel almost 3,000 cars and save 3,400 tonnes of oil equivalent, corresponding to 8,580 tonnes of CO2 less in the atmosphere.
With 660 tonnes of dairy industry wastes and by-products per day, the AF Bioenergie plant in the province of Vicenza, is able to produce 9.4 million Sm3 of advanced biomethane per year for feeding into the national gas network. The plant can power 6,380 vehicles a year, saving around 7,300 tonnes of oil equivalent and 18,300 tonnes of CO2 in the atmosphere.
The treatment of meat waste also provides interesting opportunities: The IMC Guzzo plant has been running for a number of years and produces 2.46 million kWh of electricity per year from biogas using slaughterhouse waste (6.4 t/day).