Wastewater derived from olive oil production



Reference flow in the MFA for which is suitable the technology

Olive oil production; residue from olives after olive oil extraction (plant tissue waste)

Incoming input

Incoming input in olive processing facility is olive from which about 70% is the byproduct and 15% refers to the acidified water extracted from olive fruit. On the other hand, in fish processing plant input is fresh fish (anchovy and sardines) from which about 501 tons of biological byproducts or fish residues is produced.

Outgoing output

Olive, as input is processed in two ways to get the output: (1) Separation of olive seed before the process of grinding olive pulp and oil extraction and (2) Grinding the olives together with olive seed prior to oil extraction. Due to this, two types of waste are formed; olive seed and grounded mixture of olive seed and olive pulp. In further processing, the separation of solids, olive oil and water is performed. Extracted acidified water is stored in for that purpose in storage container. In fish processing plant, output product is salted canned fish with the identified waste streams with which CE technology could be performed: Biological byproduct after cleaning/gutting fish, fish oil from wastewater and salt (NaCl) from wastewater.

Technology description

In olive oil production, there are three main thermo-chemical methods by which energy source can be utilized, namely gasification, briquetting and combustion (direct firing) or cocombustion (co-firing). Another type of gasification involves the generation of biogas (methane) by the anaerobic degradation of olive-mill wastes. Efficient use of olive cake in energy production solves two problems in one step: clean energy production and acceptable disposal of waste drom olive oil production. Also, there is a beneficial use of olive mill wastewater and its end products is anticipated, such as by recycling the treated water, and using the residues as fertilizer either directly or after composting or as raw material for antioxidant production. Sludge from the treatment can be utilized as fuel either by burning directly or after biogas production. Residues can be also used for thermal energy. It needs to point out that olive production in Croatia, in this moment, produce relatively small amount of residues and the production is dislocated. But in line with the increase of renewable sources of energy as one of the main goals of Croatian energy development sector, these could be considered as positive initiatives and a possible optimal solution for Croatian millers. On the other hand, In production of canned fish, about 1020 tons of salt per year is used, of which about 40% is discharged with wastewaters, ie about 400 tons of salt that can be extracted from wastewater through several different methods and technologies. One of the technology is biorefineriy. Considering that fish byproduct contains a high share of fish oil (more than 20%), proteins and water it is possible of producing omega 3 oil. During the process of thermal processing of sardines in the process of canned sardines production, surplus fluid from the canned fish (water, fish oil, proteins, fat) also ends up in wastewaters. It is assumed that wastewater drains more than 125 tons of fish oil each year, which could be separated by a centrifugal oil separator and used for various purposes, from the production of omega 3 oil to biodiesel production. In canned fish production, the collection of anchovy residues can be separated in two groups: heads and spines, and anchovy remains. Technologie that can be used is transportation of dried anchovy residues to minimise the total mass transported. On one hand, heads and spines can be used to produce fishmeal and fish oil, whereas the anchovy remains can be employed to produce anchovy paste. On the other hand, anchovy residues can be incinerated to obtain energy

Organizative processes to support closing the loops

Technology mentioned above can be a big part of the implementation of CE and closing the loop of waste generation. In our region, as already mentioned several times, industry is not very developed and companies are mostly small. So, in the organizative processes, companies have two options; to invest in technology alone, and to use it only for their needs and their waste generation, or to connect with other small companies of the same products and use the technology together in order to reduce and share the costs and to have more benefits of it. In addition, Split – Dalmatia County beside the mainland and hinterland part, includes four islands. In case of connecting companies, transport of waste from companies on islands needs to be included in organization processes.

Practitioners opinion

In these processes the opinion of practitioners is important. In our interviews with the potential practitioners of proposed technologies for selected waste streams, we have got some useful information about implementation. For example, after production of olive oil or canned fish, generated waste is not handled very well, so companies have to pay waste removal to other companies, what is a big cost for them. After applying proposed technologies of CE in waste generation, waste removal will not be necessary and therefor, costs can be reduced.

Possible limiting factors

Limiting factors in implementation of technologies can certainly be a problem. The main factor is that we cannot know how many people will be necessary for technology as well as how much technology will cost. In our Country that is not a common practice, so implementation can have some difficulties. Also, industries in our pilot regions are small, so maybe they want be able to implement technology alone, due to big costs. So, at the local scale, degree of implementation can be to join together all small producers of the same or similar product, in order to work together on implementing the technology that benefits them all.

PP’s opinion of the technology

PP’s are informed about the technologies not only now, but also during the previous deliverables connected to the Project, as well as during the whole processes of collecting information and visits to the selected companies and producers. PP’s also see big potential in development of these technologies, not only for the companies but also on the region level to. For them, especially interesting is possible cooperation between small producers in order to achieve better goals and solutions in CE and waste prevention.

Concept and conclusions how the technology can affect the CE effect

Technology can be very important for CE effect. Waste is a big problem for the producers because is a big cost, and it can be benefit with the use of good and developed technology. Results can be very promising but it have to be very careful and realistic. Also, it is important to make a financial analysis together with the risk analysis to see how realistic technology is and if the development of technology is realistic. From the local aspect, concept of the technology would be helpful and beneficial not only for companies but also for the regions

Is the technology a BAT?


Charts, photo, diagrams

Considering selected flow, waste from canned fish production is listed as most relevant, and it is described in Part 1b, and technology related to the olive oil production is shown in the pictures below for the BaU scenario and CE solution. 


For the previous information source we used our direct contact with companies.

During the first phase, we have conducted field research, which has given us better understanding of the waste flow and possible improvements in the chosen industry and technology. We have interviewed several facilities of each type of industry and during our visits we had full tour of industry processes as well as insight on the technologies which can improve CE effect and generation of the waste. 

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