One of the objectives of the Conserval project was to analyse the relevance and impact of the canning sector in Galicia and Northern Portugal. The Association of Canned Fish Manufacturers of Portugal (ANICP) and the National Association of Canned Fish and Seafood Manufacturers (Anfaco-Cecopesca), based in Galicia, were in charge of this action.
Interviews were conducted at different canning factories from both regions in order to:
- Quantify the waste flows from canning plants.
- Assess the economic impacts on companies for managing by-product or wastewater flows
Fourteen companies agreed to answer the questionnaire: nine companies were from Galicia and five were from Portugal.
Most companies who took part in the survey in Spain were canning companies (56%), although some were dealing with fresh or frozen products or combinations thereof and canned products were also included in the study (44%). In terms of company size, 55% of the companies were small/medium sized and 44% of those surveyed considered themselves to be “large companies”, either in terms of size or turnover.
In Portugal, responses to the survey were mostly from medium-sized companies (80%), and all of them using canned food as their main product. After the analysis, it is possible to conclude that:
In relation to by-product flows:
- BY-PRODUCT CATEGORY:
Most companies – 10 out of 14 respondents – claim to manage waste from Animal By-Products Not Intended for Human Consumption (SANDACH), category 3. Materials in this category are products that are suitable for human consumption, but are not used for commercial purposes.
The two companies that have declared to manage SANDACH category 2, which includes by-products that could have some risk, even if they are not contaminated or contain prohibited substances, are a large company working with cephalopods and another large company working with various types of raw materials such as tuna, salmon and mackerel.
The flows of these by-products range from 300 tonnes per year to more than 4,200 tonnes depending on the type of company.
Medium-sized canneries, which process different types of products, are those that generate the greatest quantity of SANDACH type 3 by-products.
In relation to wastewater flow, purification cost and types of treatment:
- PURIFICATION COST: Annual expenditure ranges from EUR 50,000 to EUR 200,000.
- TYPES OF TREATMENT:
Only one of the companies surveyed has integrated anaerobic treatment for energy recovery in the effluent treatment line, so its costs could be significantly reduced.
Anaerobic treatment consists of a process carried out by specific bacterial groups that transform organic matter into a mixture of gases, mainly methane and CO2, in the absence of oxygen. These gases are known as biogas. The anaerobic digestion process for the generation of biogas, studied at Conserval, is normally carried out in closed tanks called reactors and has economic and environmental benefits because of the production of energy.