Reverse osmosis (RO) is a common filtration system choice for water utilities across the country, and with good reason—RO is highly effective at removing solids and contaminants like salts, heavy metals and chemicals from drinking water. The technology invented in the 1950s has become popular for uses ranging from purifying household drinking water to processing highly saline seawater.
But conventional RO processes are not without their shortcomings, and new innovations are leading to more efficient and effective RO systems. For water utilities that want to filtrate water thoroughly and with as little waste as possible, it’s important to know the benefits and drawbacks of different systems. Here are some common problems that come with traditional RO systems, and how new RO systems are remedying those issues.
1. They waste a lot of water
One major issue with conventional RO systems is the fact that they can take a lot of water to operate, wasting more water than necessary during the filtration process. According to a post from the Alliance for Water Efficiency, RO systems can waste up to 20 gallons of water per each gallon of filtered water produced. In a time when water is an increasingly important resource to keep clean and conserve, it’s important that utilities waste as little water as possible and process it efficiently.
RO systems by nature produce wastewater that’s often corrosive and brackish, but industry innovations are paving the way for new membrane technologies that can withstand harsher water conditions. Additionally, RO systems now have the capability to process brackish water through higher pressure and proper pre-treatment.
2. They can remove beneficial minerals
Some also take issue with the fact that since RO is so effective at removing impurities, it can remove natural minerals that are actually healthy for human consumption like calcium and magnesium. However, others argue that water isn’t a significant source of minerals anyway when compared to food and supplements.
3. Membranes get clogged easily
Another common issue with RO systems is membrane fouling and scaling, which happens when materials build up on the membrane and slow down the flow of water. A plugged membrane limits recovery rates, increases the need for cleaning and reduces the life span of the membrane. If this isn’t addressed properly, operational costs increase and compromised equipment can result.
A newer technology (pictured), Flow Reversal RO (FR-RO) increases process recovery by 10 to 15 percent, reduces brine volumes required for disposal by up to 60 percent and reduces anti-scalant chemical consumption. As a low-waste solution, it nearly reaches zero liquid discharge, an important consideration from a regulatory and sustainability standpoint. For RO systems using this technology, this ultimately results in less waste and less overall energy use for an improved environmental impact and reduced operating costs.
For cities and utilities concerned with sustainability, investing in cost- and energy-efficient RO systems that reduce waste and run smoothly is a big step in the right direction.