Harn R/O Systems Blog

Pretreatment: The Last Line of Defense for Your R/O Membranes

Posted by Julie Nemeth-Harn on May 10, 2021 9:00:00 AM

Some raw feed waters contain suspended particulate material. This material is commonly sand, iron oxides, clay or elemental sulfur. Introduction of such materials into the membrane system can cause the development of excessive system differential pressure (dP), or even complete blockage of the brine channels with the resultant reduction of permeate flow. It can also cause physical damage to the membranes themselves. This usually results in a decrease of permeate quality and reduction of membrane life. Cartridge filtration is normally a simple and cost-effective way to reduce the amount of particulate matter reaching the membrane surface.

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Topics: membrane filtration, membrane treatment system, membrane treatment, water treatment, membrane plants, water quality, ro calculations

How Much Should My New Membrane Treatment Plant Cost?

Posted by Julie Nemeth-Harn on Mar 8, 2021 9:45:00 AM

Since Harn R/O has been in the membrane treatment business for more than forty years now, we have seen our number one question from engineers and potential owners transition from “will membranes work on my water source?” to “how much will the membrane treatment plant cost?”.

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Topics: membrane treatment, membrane plants, water treatment plant

Membrane Water Treatment: A Simpler and More Cost- Effective Process Than You May Think

Posted by Julie Nemeth-Harn on Dec 21, 2020 11:44:00 AM


Membrane filtration can be explained as a method of allowing certain materials to permeate a surface while blocking others. For water, this means allowing clean water to flow through the membrane while eliminating sediments and other materials or pathogens. Membrane filtration is a multiple-step process which is considered to be one of the most cost-effective water treatments available.

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Topics: membrane filtration, membrane treatment system, reverse osmosis, membrane treatment, water treatment, membrane plants, save money, water treatment plant

How to Calculate Percent Recovery and What Affects it in a Membrane Treatment System?

Posted by Julie Nemeth-Harn on Oct 5, 2020 1:10:00 PM

Membrane systems operating at 82% recovery will convert 82% of the total raw water input into treated permeate, with the remaining 18% being sent to waste as concentrate (or reject). The recovery rate is monitored using flow meters installed in the permeate and concentrate piping.

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Topics: membrane filtration, membrane treatment system, membrane treatment, water treatment, membrane plants, water quality, ro calculations

How Much Water on Earth is Drinkable?

Posted by Julie Nemeth-Harn on Jun 23, 2020 8:30:00 AM

Water is one of the most important commodities that supports life on earth but very few understand how hard it is to get clean, potable freshwater. Water, in all its forms, covers three quarters of the Earth's surface. The water levels on Earth remain relatively the same each year. Every day, water goes through a cycle that sees it flow from land, to the seas and then evaporates into the atmosphere through the processes of evaporation and precipitation.

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Topics: membrane filtration, membrane treatment system, reverse osmosis, membrane treatment, water treatment, clean drinking water, membrane plants, water recycling, water quality, water purification process, save water

Use Variable Frequency Drives to Save Energy in Membrane Plants

Posted by Julie Nemeth-Harn on Jan 17, 2020 1:35:00 PM


Variable frequency drives (VFD) are becoming the popular choice for many industrial processes that need to make use of motors with changing speeds. In membrane plants, these motors are used to feed the pressure and flow of the water as it moves through the various areas of the treatment cycle.

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Topics: membrane filtration, membrane treatment system, membrane treatment, water treatment, membrane plants, vfd, water purification process, save money, water treatment plant