Bonduelle has been known across Europe for over a century – and in North America for the past decade – for its fresh, canned, frozen and prepared food. The group, which canned its first peas in 1926, now provides an array of 50 staple vegetables in 500 different varieties. Established in Hungary since the early 1990s, it expanded its operations in the country in 2012 with the acquisition of a local canning factory, Kelet-Food. However, since 2010, Hungarian regulation has introduced stricter criteria for the treatment of wastewater and a whole range of other pollutants before their discharge into the environment. Following this acquisition, Bonduelle was therefore obliged to improve the treatment of its effluents.
THE TECHNOLOGY IN DETAIL
The Nagyköros plant uses both anaerobic and aerobic bacteria. The wastewater pollution serves as a food source for the bacteria, which eliminate the pollution by absorbing it. In an aqueous environment without the presence of dissolved oxygen in the water column, the anaerobic bacteria consume the COD (Chemical Oxygen Demand, i.e. the organic pollution content) in the water and convert it into simpler molecules such as sugars, alcohols, acids, different nitrogen forms, carbon dioxide (CO2), and methane (CH4). In the second stage, in the presence of dissolved oxygen, the aerobic bacteria consume these organic materials and remove the nitrogen forms. This results in fully biologically treated, clean effluent water. The anaerobic part of the plant is a closed basin, allowing us to collect the methane (biogas), then cool and compress it before introducing it into the boiler to generate steam.
“The biogas is much better for the environment than natural gas,” says Veolia Hungary’s Head of Industrial Energy Services, Tibor Lukács. “Before its transformation, the facility had major problems linked to water discharge. This difficulty was resolved with the construction of a wastewater treatment plant. There remained the issue of biogas, which was then burnt, which had a negative impact on air quality. We therefore suggested recovering the biogas generated from the anaerobic digestion process used to treat the sludge at the purification plant. Mixed with natural gas, this biogas is transformed into steam in a back-up boiler that had previously been of little use. The steam then serves to heat the factory and power different manufacturing processes.”
Bonduelle has therefore been able to reduce its energy bill by 17%, saving the consumption of 350,000 m3 of natural gas and avoiding 650 metric tons of CO2 emissions per year.
Hungary joined the European Union in May 2004, and as part of its accession package was required to comply with the 1991 European Union Urban Waste Water Treatment Directive by the end of 2015. The country already had its own General Rules of Environmental Protection Act adopted in 1995. However, along with Romania, Hungary decided to apply more stringent wastewater treatment regulations over its whole territory. In 2011, through the Act on Water Supply, the country therefore introduced stricter legislation to improve wastewater treatment and protect natural resources, along with measures regarding cost recovery and the ‘polluter pays’ principle. Companies such as Bonduelle, which use water in their manufacturing process, therefore needed to ensure that they were in line with Hungarian standards.
Adapting a successful model
In the light of Nagyköros’ success, Bonduelle and Veolia worked on a similar project for the Békéscsaba factory from 2014 onward. However, there was one difference: there was no back-up boiler that could be converted. Instead, Veolia recommended renovating the two boilers at the factory and dedicating one of them to use a mixture of natural gas and biogas. As the calorific value of biogas is lower than natural gas, this project required the use of a special regulator to mix the natural gas and biogas for consistency of output. The resulting benefit has been 16% savings in energy costs, while 95% of the biogas has been recovered and used to supply the factory with steam.
Sustainable Development Manager, Bonduelle
“Normally, vegetable canning technology needs a lot of fresh water, especially for washing the vegetables, which is why there is a lot of wastewater. At our Nagyköros site, until 2011 we sent all of our wastewater to the neighboring town, paying considerable sums for it to be treated by the communal purification facility. But we quickly realized that the town plant could no longer cope and that the effluent water to the river was dirty. We decided to solve the problem ourselves, rather than entrust it to the town, because the two technologies used to treat the communal and factory wastewater are very different. The new Hungarian regulations also gave us a period to think about the solution. At the beginning of the season in 2011, we started the test run of our new wastewater treatment plant. Since then, it’s been a winwin situation in terms of both the industrial process and national regulations.”
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