With proper design, high quality manufacturing, and ongoing maintenance, reverse osmosis (RO) systems can reliably deliver high purity water for applications ranging from drinking water to pharmaceutical production and semiconductor manufacturing. This capability makes them an essential water purification tool for many businesses.

The key to realizing the benefits of an RO system over the long-term is partnering with experts to select the right system, components, and ongoing service plan based on your specific water treatment objectives. This article provides guidance on how to find and scope an RO system tailored to your needs.

Finding the Right RO System

When searching for an RO system, the first step is determining various design factors you should consider for your end use:

Determine Your Water Quality Needs

Getting a professional water analysis is crucial for appropriately sizing and designing an RO system. The analysis will quantify the mineral content, known as total dissolved solids (TDS), along with other parameters like pH, calcium, total suspended solids (TSS), iron, and silica levels, among others. These water quality parameters provide insights into:

• The level of influent water quality contaminant levels
• Potential operational impacts to membrane life
• Any necessary pretreatment to protect the membranes and ensure your team meets your water quality demands

Without this water quality baseline, you risk undersizing, overengineering, or overpaying for your system’s components and membranes.

Determine Required Permeate Flow Rate

In addition to water quality, understanding your required RO permeate production rate is also essential. Key questions to answer include:

• How much treated water do you need to produce each day for your end use?
• What is the maximum feedwater flow rate you can supply to the RO system?
• What level of efficiency do you want from your RO system?

Carefully projecting both your daily demands and the water source’s production rate prevents shortfalls in treated water and minimizes the risk of downtime for your process – be it drinking water or industrial cooling. It also prevents overbuilding a system beyond your site’s capabilities.

Getting accurate water quality and demand parameters early allows RO vendors to right-size a system to your needs. It also paves the way for optimizing the broader facility, pretreatment, and concentrate disposal design.

Space Constraints

Understanding installation space limitations is necessary to determine if an off-the-shelf or custom RO system is more appropriate. Key considerations include:

Size and Footprint Limitations:

Standard RO skids have a relatively fixed width and length when supporting certain production flow rates and ranges. If your facility has tight space bounds, or if you are looking to tailor a system to your production process, a smaller custom-designed system may better suit your needs. Custom systems can take advantage of several unique design options, including vertical configuration and difference membrane array layouts, to ensure you get the best use of the space you have available.

Custom vs. Off-the-Shelf Systems

While pre-engineered systems you can find online may be more budget-friendly initially, a tailored RO design allows the vendor to match your treatment production goals with your specific water quality, end use, and other site-specific variables. The expertise to deliver custom systems also facilitates integrating advanced remote monitoring and process controls.

Power Requirements

RO systems have relatively modest power demands but verifying electrical infrastructure caps should be performed prior to purchasing any water treatment system.

Small Systems

Low-capacity RO systems producing up to a few thousand gallons per day can typically run on standard 120V power.

Larger Systems

As permeate production requirements increase into the tens of thousands of gallons daily, RO systems often require 460V, 3-phase power with higher amperage ratings. Lacking adequate electrical service could add unexpected costs for upgrades.

Getting clarity on space and power accommodations early gives vendors the details to engineer an RO system aligned with your facility’s realities. This avoids unanticipated restrictions down the road.

Pretreatment Requirements

RO membranes are highly effective at removing dissolved contaminants, but proper pretreatment protects them from particulates, bacteria, and scaling. Common forms of pretreatment include:

Filtration

Multi-media filters, cartridge filters, bag filters, ultrafiltration, and other mechanical filtration will help remove suspended particles that could plug RO membranes.

Chemical Injection

Injection of anti-scalants prevents mineral scale accumulation on membranes, while pH adjustment helps control corrosion. Analyzing the water chemistry determines which chemicals to apply and at what dosages. Oftentimes sites may be limited by ions such as silica, and a properly dosed antiscalant can help minimize the risk of this limiting ion from scaling the membranes.

Other pretreatment steps like activated carbon absorption and dechlorination may also be advisable depending on the feed water quality. Optimized pretreatment not only safeguards RO membrane integrity but also reduces the frequency of costly cleanings.

Disposal Requirements

While RO systems produce an exceptionally pure permeate stream, they also generate a concentrated waste stream. The disposal method for this concentrate depends on the following:

Local Regulations

Businesses must follow federal, state, and municipal statutes dictating allowable total dissolved solid, chloride, and other ion concentrations for surface water discharge. More stringent limits or surcharges for higher TDS loads may apply.

Alternative Options

If regulations restrict surface water disposal, concentrate volume reduction technologies, trucking services, or evaporation ponds are viable alternatives. Some sites also use RO concentrate for onsite beneficial reuse in cooling towers or irrigation.

Vetting discharge alternatives and limitations early allows for adequate planning and budgeting for long-term concentrate handling.

Scoping and Designing Your System

Once the steps for gathering key requirements are complete, collaborating with an experienced RO system vendor speeds up the process of moving to the design phase. Elements to scope out include:

Work with Vendor on Custom Design

Reliable vendors have the expertise to complete detailed system designs tailored to your objectives. This analysis looks at:

• Array configuration specifying the membrane staging
• Number of membranes to meet daily purification volumes
• Materials compatible with your feed water chemistry
• Space constraints, if any

Optimize for Efficiency and Recovery Rate

Proper system design maximizes water recovery as a percentage of the incoming feed rate to reduce water waste. The recovery rate potential depends partly on your water analysis. This will also allow your team to balance initial Capital Expenditures versus ongoing Operating Expenditures.

Permeate Flush for Maintenance

Adding an automated permeate flush that periodically floods the system with purified water helps control scaling and extend membrane life.

Trend Analysis and Remote Monitoring

Sophisticated monitoring and data transmission to the cloud allows vendors to flag performance issues before they become problems. Expert analysis of operating trends is key for preventative maintenance.

Work with Service-Focused Provider

Prioritizing upfront system design positions you for effective ongoing service partnerships. This focus on lifetime support ensures smooth, reliable, long-term RO performance. Carefully scoping an RO system with a reliable and responsive water treatment provider gives you the purification capabilities and resilience needed to meet your objectives.

Investing in the right RO system for your business is not only a smart financial decision but also a commitment to providing clean, safe, and high-quality water for your operations. By following these guidelines and carefully evaluating your options, you can confidently choose an RO system that will serve your business well for years to come. EAI is a service-focused provided that can help you design the best water treatment solution for your facility. For more information, contact us here.