7 Stage Reverse Osmosis

What Do I Need to Know Before Purchasing a Reverse Osmosis System?

What Do I Need to Know Before Purchasing a Reverse Osmosis System?

So, you've decided to get serious about researching Reverse Osmosis Systems before making a purchase. Perfect. Here are some more things to consider:

  1. Do I need to buy a tap? RO systems require a separate tap for the treated water to dispense. Did you know you can upgrade your RO faucet to match the colour, finish and style of your existing kitchen sink fixtures?
  2. Wondering how many stages of filtration an RO system should have? RO systems typically come in 5, 6 or 7 stages of filtration. At least 5 stages is typically recommended for most applications.   Our 6 stage system adds a re-mineraliser to which enriches water with elements such as calcium and magnesium.   Our 7 Stage system adds a further Ionizing cartridge to this process.
  3. If you're on well water or an area with high levels of sediment, you may want to consider a system that has extra pre-filtration (5 stages). Our Aquafilter RO systems will provide adequate filtration for most applications, but you might want to consider an additional pre-filtration system.
  4. What about water hardness? Does incoming water have a hardness level above 7 grains per gallon (gpg)? Keep in mind that an RO system is not a water softener and if your water is above 7 gpg hardness, water softener pretreatment will help preserve the life of an RO system and membrane, although not required.
  5. Does an RO System Waste Water? Similar to how we use water to wash our dishes, clothes or vehicles, RO technology uses water to clean the RO membranes as they process water. During the filtration process, RO systems typically use more water than the filtered water it produces. But because the system shuts down once the storage tank is full, water does not continue to run down the drain. Some systems are more water efficient than others. If this is a concern, check out the APURE SENNA nero Reverse Osmosis System.
  6. How much water can a system produce? Expect a GPD (gallons per day) production rate of 50% to 75% of system GPD rating. While it's true that no one really uses 50+ gallons of drinking water per day, the “50 GPD rating” is the speed that an RO system makes drinking water and actually produces a gallon of water per hour (with normal water pressure of about 60 psi). Thus, a 50 GPD-rated system will provide adequate production for the common household and will not cost much more than a lower GPD-rated system.
  7. Would you like RO water for your ice maker? Add a refrigerator icemaker adapter kit to easily get RO water from your icemaker. You'll no longer need to buy a separate refrigerator filter.

What's our most popular RO system? The most common system purchased by customers is the Aquafilter 7 Stage Reverse Osmosis System due to great value, made in the EU, simple installation, and quick release filters for easy filter changes.

Aquafilter 6 Stage Pumped Reverse Osmosis System

Aquafilter 6 Stage Reverse Osmosis System with Mineralizing Cartridge

Aquafilter 6 Stage Pumped Reverse Osmosis System

Aquafilter 6 Stage Reverse Osmosis System with Mineralizing Cartridge with pump

7 Stage Reverse Osmosis

Aquafilter 7 Stage Reverse Osmosis System with Mineralizing Cartridge

HyroTech Alfa Flex Filter Panels

New Alfa Flex Panel

Sterner is proud to release the new patented Hydrotech filter panel named Alfa Flex. The Alfa Flex filter panel is a breakthrough in designing of filter panels and can increase the capacity of existing drum filters up to 20%. The Alfa Flex filter panel is compatible with almost all drum filters, which are able to fit existing Hydrotech type drum filter panels.

Filtration Speed

Sludge Production (Volume)

Sludge Concentration (NTU)

Mounting instructions (standard assembly execution)

  • One panel per segment will be mounted in the “lifting” direction (+ symbol in the rotational direction). All other panels will be mounted with the symbol – (non lifting) in the rotational direction.
  • The lifting panels will be mounted in a straight row (same position on the drum) throughout the length of the drum, see picture below.
  • If the ALFA-Flex filter panels should be mounted in any other way or if the old filter panel should be used, it should be clearly indicated in the production order.

Smolt plant invests in sludge drying

Ranfjord Fiskeprodukter will invest about 20 million NOK in sludge treatment at its smolt plant in Mo i Rana. The environmental investment is made to meet public requirements. It is the sludge from the filtering of the effluent which will be dewatered and dried.

The process solution consists of thickening, dewatering and evaporation. In practice, zero effluent will be obtained from the sludge treatment itself. This is accomplished by purifying the rejection water from the sludge thickening by ultrafiltration.

“Using this sludge treatment, we achieve an overall lowering of our effluents, thus fulfilling public requirements,” says Bjørn Myklebust, managing director at Ranfjord Fiskeprodukter.

At the same time as the investment meets environmental concerns, the sludge will be dried to 90% dry matter.
“It is important for us to get a dried and stable end product. At the same time we use a drying process that is gentle on the nutrients in the sludge, so that it can become the most useful fertilizer product. The aim is to contribute to a circular solution, where waste from fish farming will play a part in agriculture,” says Myklebust.

The drying process utilizes heat pump technology. The process includes several stages where a special Norwegian-developed onion thickener gives a very effective thickening.

The complete sludge treatment plant will be delivered by Sterner and the design basis for the plant is 600 tonnes of fish feed per year.
“We chose the solution after seeing similar plants in operation,” says Myklebust.

The actual sludge treatment accounts for half of the total environmental investments. Sterner has so far delivered 12 sludge treatment plants to the aquaculture industry and besides also works with the production of biogas from corresponding sludge.

Ranfjord Fiskeprodukter AS is located at Mo Industripark, about 2 kilometers from Mo i Rana center. An annual 5.5 million smolt is produced, from 2 plants in the industrial park. The business is owned by fish farmers and has 10 employees.

Land based post-smolt ongrowing will reduce sea period with almost 50 %

Eidesvik Group produces yearly 4500 tonnes  of salmon from their own smolt plant and at four sea sites. To shorten the period at sea, the Group now builds a post-smolt plant of NOK 45 mill. The plant comes with integrated recirculation of water.

“Today the smolt is 100 grams when launched at sea. The growth period before harvest is between 18 and 20 months. If we let it grow 3-5 months in the post-smolt unit it will be presumably 500 grams when put in sea cages. And so the period at sea will be less than one year,” explains Lars Magne Eidesvik of Eidesvik Settefisk, part of Eidesvik Group.

In addition to shorter production time, a large post-smolt will be more robust and less prone to diseases, which leads to lower mortality and higher product quality. The existing smolt plant will supply the fish going to the post-smolt plant, which will have a capacity of 600 000 fisk yearly, in three cycles.

The water temperature in the post-smolt plant will hold between 12 and 16 degrees C, which will ensure good growth. There will be two large fish tanks, five meters deep and 15 meters in diameter. We water treatment will be in a separate building and consist of screen filter and biofilter. To keep the CO2-content down there will be a two-step CO2 removal, which also ensures a low ammonium level. The plant will run on brackish water. The plant will neighbor the existing smolt plant.

The thickening of waste will commence in the center of the fish tank, due to a new hydraulic design and a special outlet solution. The central outlet will have several functions: fish exit, sludge exit and dead fish exit.

“The outlet is supported by a higher turnover of water and is the key to effective capture of concentrated sludge. We have conducted pilot trials of this part in cooperation with the client,” explains Steinar Skybakmoen of Sterner, who will build the tanks and the recirculation system.

The post-smolt plant is number five in a row delivered by Sterner. The buildings will be constructed by local entrepreneurs, under the leadership of Multiconsult, who will design the building.

“The plant will ensure a good total economy through a high feed conversion ratio. It will also ensure a good water quality for the fish and clean tank environment,”  according to Mr. Steinar Skybakmoen of Sterner.

For further information on Post-Smolt, contact Mr Steinar Skybakmoen +47 48 04 72 04  email: ssk@sterneras.no