Project Background & Pain Points
A large land-based Atlantic salmon recirculating aquaculture base on Canada’s west coast adopts high-density indoor RAS breeding mode, equipped with two core systems including water cooling heat exchange and ultrafiltration water purification. The daily circulating water volume reaches 1200m³, and precision filtration is required to protect the rear plate heat exchangers and ultrafiltration membrane components. The aquaculture water mixes offshore seawater, fish manure, leftover feed and organic flocs. Tiny viscous impurities easily block heat exchange channels and ultrafiltration membranes, which has long been an operation and maintenance difficulty.
The original security filter tank of the factory was equipped with traditional standard small PP filter cartridges, with 18 cartridges installed in a single tank. This solution has multiple drawbacks: the cartridges feature low dirt holding capacity and get clogged quickly by fish manure colloids. The whole tank must be shut down for replacement every 3 months, and each disassembly, assembly and exhaust takes more than 2 hours. Water temperature fluctuates during shutdown, causing stress on salmon and slightly increasing fry mortality. Frequent cartridge replacement brings high consumable and labor costs, and the expensive local labor fees create a heavy long-term operation burden.
Meanwhile, the thin filter layer of traditional cartridges allows tiny organic particles to penetrate and form water flow short circuits, leading to frequent biological fouling on the inner wall of heat exchangers which need light flushing every week. The cleaning cycle of ultrafiltration membranes is shortened to every 45 days, accelerating the loss of membrane consumables. The densely arranged cartridges inside the tank leave narrow disassembly space, and poor sealing during replacement further causes filtration failure. The client put forward clear demands: replace with LEFILTER high-flow filter cartridges compatible with the original tank without reconstruction, extend replacement cycles, reduce cartridge quantity, cut downtime and operation costs, and block organic impurities at the source to protect heat exchange and membrane equipment.
Customized LEFILTER Solution
Referring to the aquaculture-specific filter cartridge solution on LEFILTER overseas official website, we replaced the original cartridges with HF series 6-inch rodless high-flow folded filter cartridges for the client. Only 3 cartridges in a single tank can achieve the equivalent total flux of the original 18 small cartridges, which are directly compatible with the flanges of existing stainless steel filter tanks. No pipeline or tank modification is needed, and the whole renovation construction is finished within 1 day.
First of all, the filter cartridge adopts food-grade multi-layer gradient polypropylene filter material with 5μm precision. The outer layer intercepts large particles such as fish manure and leftover feed, while the inner layer captures colloidal suspended solids. It adopts an integrated double-layer support frame and hot-melt welding process without adhesive precipitation, resisting seawater salt corrosion and immersion in organic water to adapt to salmon breeding water quality. The inside-out water flow design matches the integrated widened rubber sealing ring to eliminate short-circuit filtration. The maximum flow rate of a single cartridge is far higher than traditional ones, with low initial operating pressure difference that will not increase the load of water pumps.
In addition, an integrated anti-slip handle is set on the top of the cartridge, allowing single-person quick disassembly without tools. Its dirt holding capacity is 7 times that of traditional cartridges, greatly extending the service cycle. All filter cartridges meet North American aquaculture water safety standards. LEFILTER overseas warehouses deliver goods in stock, customs clearance and delivery are completed within 6 days, and overseas engineers are on-site to finish installation, pressure difference debugging and operation training.
Operating Effects & Client Benefits
The filter cartridges have operated stably for 14 months after commissioning, completely solving all defects of the original filtration system. The cartridge replacement cycle is extended from 3 months to 17 months, with replacement frequency reduced by 83%. Single shutdown time is shortened to less than 25 minutes, and annual shutdown losses are greatly cut. The water temperature of the cooling system remains stable, salmon stress problems are basically eliminated, and fry survival rate is increased by 13%.
Under the same flow rate, the number of filter cartridges is reduced from 18 to 3, cutting the total annual cost of cartridge procurement and manual disassembly & assembly by 72% and significantly lowering the factory’s operation expenditure. High-precision deep filtration effectively intercepts organic pollutants in water, reducing the blockage and fouling frequency of rear heat exchangers by 88% and canceling weekly flushing procedures. The erosion of ultrafiltration membranes by impurities is relieved, the chemical cleaning cycle recovers to the standard 90 days, the service life of membrane components is prolonged, and the annual membrane replacement cost is saved. The large-diameter filter cartridges simplify the layout inside the tank with spacious space for inspection and maintenance, and all operations can be completed by one person to sharply reduce maintenance workload. The corrosion-resistant structure of the cartridges will not be damaged or leak after long-term immersion, and no harmful substances are dissolved out in the whole process. The ammonia nitrogen and suspended solids indicators of aquaculture water remain stably up to standard, the incidence of fish diseases drops, the dosage of aquaculture chemicals is reduced, and finished salmon complies with North American export food specifications.
With minimal renovation cost, this set of high-flow filter cartridges realizes triple optimization of filtration efficiency, equipment protection and operation cost reduction, serving as a benchmark precision filtration solution for overseas aquaculture recirculating water of LEFILTER.
