At Hodowla Ryb K-2, trout are farmed intensively using a sophisticated recirculation system. Currently 400 tonnes of trout a year are produced on the farm, a figure that is soon due to rise to 600 tonnes.
Jacek Juchniewicz, the owner of Hodowla Ryb, wears a second hat as president of the Polish Trout Breeders’ Association, a body that has some 100 members representing almost the entire production of trout in Poland. Output has increased steadily the last few years. Official statistics in Poland state that just over 16,000 tonnes of trout (including rainbow, brook, and Arctic charr) were produced in the country in 2014.
Dependence on river water affects production
Marcin Juchniewicz, the son of Jacek Juchniewicz, is responsible for the day to day management of the farm. Production is intended to reach 700 to 800 tonnes a year, but this target will not be reached in 2016, he says, as temperature fluctuations in the water that supplies the farm have affected the volumes produced. The water is drawn from a river running by the farm and although it is recirculated through the system this has little impact on the temperature which tends to be the same as in the river. The farm also has access to some groundwater, which has a constant temperature, but it is only a secondary source and cannot supply all the sections of the farm. The advantages of using groundwater are so marked that the company will be looking for other sources in the hope of replacing more of the river water with water from the ground.
Although the farm uses recirculation technology the consumption of water from the river is relatively high at 240 litres per second. This extensive use of freshwater means that the fish does not suffer from any off tastes that may arise when the water in the system is not changed frequently. This is usually countered by depurating the fish in freshwater in another basin before harvesting, a step that does not have to be performed at Hodowla Ryb K-2. For the moment the use of so much fresh water does not impose a cost, however there is a political debate about whether to start imposing fees for the use of this water, says Mr Juchniewicz. As fish farmers, he argues, we do not use the water, we just borrow it, and then return it to the river. Pollution is another story, however, and he agrees that if a farm pollutes the water, it must pay the cost of bringing it back to the level of cleanliness demanded by the law. The way the debate is headed means that a nominal charge is likely to be introduced in the near future.
Recirculation system adapted for better performance
The water from the river is filtered to remove the debris, twigs, leaves, as well as larger particles of mud etc., before it is released into the farm. However, the farm is located in a glade surrounded by trees and their leaves drop into the ponds particularly in the fall which generates some work in cleaning the basins. The water is stripped of carbon dioxide and aerated using diffusers. In summer the water is oxygenated using pure oxygen as well, because aeration alone is insufficient. This enables 25-30 tonnes of fish to be stocked in one basin corresponding to a density of about 75 kg per cubic m. To optimise the use of the water the basins have a sophisticated system that distinguishes between the upper and cleaner layer of water from the lower, dirtier layer. The former is channelled back into the basin while the latter is sent through a series of mechanical filters, then biofilters and finally through plant lagoon before it is released. The system’s biofilter breaks down the organic matter and the dissolved nitrogen that is contained in the water using bacteria. The biofilter is filled with small plastic elements that provide a substrate for the bacteria to colonise. The biofilter is split into twenty chambers each with 22 cubic m of these plastic elements. The filtration capacity created by this volume of these elements enables about 800 tonnes of feed to be put in the system annually, explains Mr Juchniewicz. The farm has thus two recirculation systems, the main one which mechanically and biologically filters the water from a unit of four basins and then recirculates it, while the second smaller one circulates the water within each individual basin. Additionally, all the basins are equipped with automatic feeding systems to enhance the performance of the fish and lessen metabolic stress as the fish are fed with small doses delivered at high frequency.
Grading and fish delivery system on track to be automated
On the farm classic treatment methods are followed to get rid of any parasites or pathogens that occur naturally in the river water. The disinfectants or other products are applied at low concentrations and for longer periods in order to protect the biofilter. If higher concentrations are needed this is stepped up very gradually to allow the system the time it needs to adapt to the treatment. From this perspective to the benefits of obtaining water from the ground rather than from a river are very marked. The chances of groundwater harbouring pathogens are generally far lower compared with river water. The fish are grown to portion size of about 300 g, but some are allowed to grow to 1,000 or 1,500 g and are then sold as salmon trout. Once in their lifecycle the fish are sorted by size, a process that is carried out automatically using a grader, but the idea is to increase the level of automation in the near future. When implemented the fish will be moved through specially designed system from a pond to a grader and from the grader to the pond or sales facility with even less manual operations than is the case now. It is also worth underlining that a wide scale monitoring programme is operational at the farm that keeps constant track of oxygen and pH levels as well as provides information on the functioning of all the technical facilities. All the information is combined together and sent to the monitoring panel in the control room.
|Hodowla Ryb K-2|
Keblowo Nowowiejskie 14A
84-351 Nowa Wies Leborska
Owner: Jacek Juchniewicz
Tel.: +48 59 862 2727
Manager: Marcin Juchniewicz
Activity: Trout farming
Production model: Intensive, recirculation
Production capacity: 600-700 tonnes per year
Current production: >400 tonnes
Main feed supplier: Aller Aqua
Planned: Hatchery, processing plant
While the fish is currently being sold with minimal processing Mr Juchniewicz is well aware of the benefits of greater value addition. A processing unit has been put up at the farm that is waiting for the final installation of the necessary equipment. Further developments are designed to make the company even more vertically integrated. Today the farm is supplied with fingerlings from a company in Denmark, but Mr Juchniewicz has invested in another farm in the vicinity which is being modernised and will be used as a hatchery, if the project secures funding through the EMFF. The plan is to have two activities at the new site. One to produce 50 g fish indoors in a completely isolated unit using ground water and the other to produce large fish (1,000 g) for the market. If all goes to plan, trout production in Poland will soon receive a further boost.