hrvatski

Dizajn efikasnog depuracijskog sustava sukladan potrebama hrvatskog školjkarstva

By legal provision, shellfish cultured in the highest quality sea water (zone A), as defined by microbiological quality, are distributed directly to market, once passing through a distribution center. However, shellfish from zone B must be subjected to depuration prior to being packaged. One of the fundamental problems of the Croatian shellfish industry is the lack of depuration centers. Although the theoretical aspects of the depuration process appear straightforward, various factors influence its effectiveness: handling of shellfish from harvesting to depuration, design and effectiveness of system components, physicochemical properties of the water, cleanliness of the shell, the species and initial amount of harmful microorganisms present in the shellfish, the species and the physical condition of the shellfish. Therefore, it is necessary to be acquainted with local conditions and to modify the system’s design accordingly, to assure maximum efficacy and capacity. Every depuration system is comprised of tanks and water treatment systems which have 5 basic components. These include biological filtration, temperature and salinity control, mechanical filtration, aeration, and chemical filtration. The basic factors taken into consideration when designing a depuration system are: operational effectiveness, accordance with all legal regulations, characteristics of the ambient sea water, profitability, simplicity of construction and maintenance. Considering legal regulations as well as the recommendations of the FAO and CEFAS, we designed a vertical recirculating depuration system which satisfies the requirements of the Croatian shellfish industry. In this system, sea water from the shellfish holding tanks flows into a reservoir, and is then pumped into a sand filter, where particles sized 2-5µm are removed. Following sand filtration, a diatomaceous earth filter removes particles as small as 1µm. Once mechanically filtered, the water enters a UV reactor for sterilization. The water then enters a chiller to maintain a specified temperature, a biofilter (rotating biological contactor) to remove ammonia, and a protein skimmer to remove the smallest mechanical particles, oils and lipids. The fully treated water is then returned to the shellfish holding tanks. In order to ensure the continuous operational efficacy of the system, and to provide a record of water quality conditions, a computer continuously monitors and records water flow, temperature, dissolved oxygen concentration, and periodically, salinity and pH values.

depuracija školjkaša; dizajn sustava

nije evidentirano

engleski

Design of an efficient depuration system according to the specific needs of the Croatian shellfish industry

By legal provision, shellfish cultured in the highest quality sea water (zone A), as defined by microbiological quality, are distributed directly to market, once passing through a distribution center. However, shellfish from zone B must be subjected to depuration prior to being packaged. One of the fundamental problems of the Croatian shellfish industry is the lack of depuration centers. Although the theoretical aspects of the depuration process appear straightforward, various factors influence its effectiveness: handling of shellfish from harvesting to depuration, design and effectiveness of system components, physicochemical properties of the water, cleanliness of the shell, the species and initial amount of harmful microorganisms present in the shellfish, the species and the physical condition of the shellfish. Therefore, it is necessary to be acquainted with local conditions and to modify the system’s design accordingly, to assure maximum efficacy and capacity. Every depuration system is comprised of tanks and water treatment systems which have 5 basic components. These include biological filtration, temperature and salinity control, mechanical filtration, aeration, and chemical filtration. The basic factors taken into consideration when designing a depuration system are: operational effectiveness, accordance with all legal regulations, characteristics of the ambient sea water, profitability, simplicity of construction and maintenance. Considering legal regulations as well as the recommendations of the FAO and CEFAS, we designed a vertical recirculating depuration system which satisfies the requirements of the Croatian shellfish industry. In this system, sea water from the shellfish holding tanks flows into a reservoir, and is then pumped into a sand filter, where particles sized 2-5µm are removed. Following sand filtration, a diatomaceous earth filter removes particles as small as 1µm. Once mechanically filtered, the water enters a UV reactor for sterilization. The water then enters a chiller to maintain a specified temperature, a biofilter (rotating biological contactor) to remove ammonia, and a protein skimmer to remove the smallest mechanical particles, oils and lipids. The fully treated water is then returned to the shellfish holding tanks. In order to ensure the continuous operational efficacy of the system, and to provide a record of water quality conditions, a computer continuously monitors and records water flow, temperature, dissolved oxygen concentration, and periodically, salinity and pH values.

shellfish depuration; system design

nije evidentirano