Production process, what inputs influence the process

In fish processing plant there are several directions for the development of waste organization with a view to better implementation of CE principals. Considering that, the following waste streams were identified which could be better handled and those are:
 • Biological by-product after cleaning/gutting fish (fish remains),
• Fish oil from the wastewater,
• Salt (NaCl) from the wastewater The company produces salted anchovy and canned sardines, and in 2017 a 6 265 tons of fresh fish was processed, from which about 501 tons of biological byproducts or fish residues was produced. From the byproduct, animal feed is produced. Considering that fish byproduct contains a high share of fish oil (more than 20%) and the possibility of producing omega 3 oil, it is suggested to implement oil extraction technology instead. In addition to the mentioned omega 3 oil, it is possible to produce biodiesel that can be used for the energy needs of the plant (thermal energy for the production of technological steam) and production of protein for livestock feed.

Shape, form, structure of waste

Grinded olive seed and olive pulp residues mixture – is a gel like substance. Composed of solid wastes consisting of olive pulp and pits left over after pressing the fruits, as well as liquid wastes consisting of vegetable and additional water generated during decantation
Seeds – dried, spikey and separated from the pulp with very high-energy value
Acidified wastewater – liquid form
Biological by-product after cleaning/gutting fish (fish remains) – (In the shape of fish heads, unusable fish, fish silage, fishmeal and fish sauce) Fish oil from the wastewater - liquid with high viscosity
Salt (NaCl) from the wastewater – liquid with the need for purification.

Composition of waste

Waste from olive oil production (grinded olive seed and olive pulp residues mixture) is rich on these active ingredients and antioxidant activity. By-products from the production process are mainly composed of phenolic compounds, carbohydrates, organic acids and mineral nutrients variably distributed. On the other hand, olive seeds are also very important part and they are equivalent to a hard wood with cellulose and lignin predominating and they are high in thermal energy. Composition of waste from canned fish production can be valued in various products such as proteins, oil, amino acids, minerals, enzymes, bioactive peptides, collagen and gelatin. The fish proteins are found in all parts of the fish. The amino acids present in the fish can be utilized in animal feed in the form of fishmeal and sauce or can be used in the production of various pharmaceuticals. The fish oil contains two important polyunsaturated fatty acids called EPA and DHA or otherwise called as omega-3 fatty acids.

Current destination

During the production, about 1 020 tons of salt per year is used, of which about 40% is discharged with wastewaters, i.e. about 400 tons of salt that can be extracted from wastewater through several different methods we will propose. From the byproduct of canned fish production, animal feed is produced.

Other important characteristics

Our potential solution presented in the M-scale table considers the disposal of olive residues after production in several ways that are more favorable:
• Production of high quality fertilizer for agriculture purposes
• Production of a briquette for firewood
• Reuse at the olive oil processing facility - production of heat for the needs of olive oil processing plant
• Use of acidified water for the purposes of agriculture for treating (acidifying) alkaline soil
In olive oil production, there are three main thermo-chemical methods by which this renewable 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. In Croatia, the use of olive residues for energy production is in its primary phase of development. We don’t have enough information’s from the olive oil producers, about residues usage for energy production. Those 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. 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.