Reverse Osmosis Maintenance: Your Total Guide
Reverse Osmosis maintenance is essential to ensuring that your system runs smoothly with as few hiccups as possible. When running well, a reverse osmosis system can help guarantee uniformity and increase quality output.
Performing routine inspections of your reverse osmosis system helps to avoid emergencies, extend your system’s life cycle, save money on costly repairs, and reduce system interruptions. These inspections help catch issues before they cause irreversible damage, shutting down production.
During daily routine inspection of your reverse osmosis system, you’ll want to maintain the entire system while paying close attention to fouling, water quality, regeneration and service cycle flow patterns, filters, membrane, electrical consumption, and pressure.
When should I clean my Reverse Osmosis System?
A major part of performing routine maintenance is cleaning your reverse osmosis system. On average, a system should be cleaned every three to six months or as soon as a disturbance is noticed. Generally, when your normalized flow decreases by 10%, or when the overall pressure drop surpasses 15% from the initial acceptance test conditions, you should clean your reverse osmosis system. Another sign that your system needs to be cleaned is when larger than normal amounts of solids are passing through the system.
How to Clean a Reverse Osmosis System
Now that we have established when to clean your reverse osmosis system, let’s investigate how to clean it. Over time, membranes will collect buildup of rejected solids called fouling. Flushing a membrane will reduce fouling but in order to avoid irreversible damage, a reverse osmosis system still needs routine cleaning.
Cleaning Instructions
First, check the membrane specifications that indicate the correct membrane cleaner and method. Using the wrong cleaner or method for a foulant can cause extensive damage to your system. The following are common types of membrane foulants that can compromise an RO system:
Suspended solids: Pressure drop and decreased permeate flow can signal that suspended solids are indicative of an unclean system.
Hydrogen sulfide: Hydrogen sulfide in the presence of metals will form sulfur and metal sulfides. These will decrease permeate flow and cause a pressure drop.
Metals (iron, aluminum and manganese): Metal fouling may cause pressure to drop and decrease permeate flow. When metals oxidize RO membranes, the permeate flow will be higher, and the salt rejection will be lower.
Microbial and biofilm foulants: Microorganisms can cause lower permeate productions and the need for greater pressure.
Silica: When colloidal silica causes membrane fouling, permeate flow will decrease and pressure will drop.
Hydrocarbons: Hydrocarbons will not enter the water except through human actions. This prevention is vital due to the fact that even a small amount of hydrocarbons can have a significant membrane fouling effect.
Polymers: When Polymers reach the membrane, they create a fouling film, which prevents water flow. This causes a pressure drop and decreases permeate flow.
Calcium sulfate and calcium carbonate (CaCO3): The presence of calcium carbonate and calcium sulfate can be indicated by low salt rejection and low permeate production.
Subject to the foulant type, you must implement one of the following cleaning solutions:
Low pH chemicals: used for cleaning inorganic colloidal fouling, sulfate scale and carbonate.
High pH chemicals: used for cleaning biofouling and organics.
Bacteria removal at high pH or with specific biocides: bacteria removal.
Low pH chemical and high pH chemical combination: If mineral scale and organics are present, start with a low pH cleaning chemical to remove the mineral scale and then follow with a high pH cleaning chemical to remove any organics.
RO membrane cleaning process:
Open the concentrate valve and using permeate water, flush the system.
Secure the recirculation pump to the membrane feed inlet.
Affix the concentrate outlets and permeate to the chemical tank.
While maintaining the pH level constant, recirculate the cleaning chemical for one hour.
Rinse the membrane with permeate water to remove any chemical residue.
Repeat the cycle for each cleaning chemical needed.
Replacing Filters and Membranes
Even with cleaning the membrane and filters, they will ultimately need to be replaced to make sure that the reverse osmosis system functions at peak performance. The longevity of filters varies, but typically a pre-filter needs to be replaced every month while a RO membrane should be replaced every two to three years.
When installing a new membrane, insert it in the direction that the water flows. All J Mark reverse osmosis systems come with directional arrows that mark the direction that the water flows. As you insert the membrane, make sure that the brine seal is facing away from the membrane housing, and push the membrane into the housing. If the membrane is proving too difficult to insert, you can use glycerin to lubricate the membrane to facilitate installation. Once the membrane is in the housing, position the pipe cap on the end of the housing that the arrow points to.
J.Mark Systems Can Help
Following the steps outlined in this blog will keep your reverse osmosis unit running smoothly. If you’re feeling overwhelmed by reverse osmosis maintenance, it’s time to bring in the professionals. J.Mark Systems can provide a state-of-the-art WTRBox reverse osmosis system with multiple treatment capacities that will stand the test of time.
We also offer maintenance plans, allowing you to focus on other aspects of your business while your water treatment runs smoothly. Contact J.Mark Systems today to get started!