Freshwater costs, supply limits, and discharge rules all push facilities to use less. Water reuse addresses all three. You treat water you already have and put it back to work.
Many reuse projects stall early because teams pick equipment before they understand their water. A better path starts with the process. These four steps help you find reuse opportunities and plan treatment that fits your site.
Step 1: Map Your Water Streams
Start with a simple water balance. Track where water enters your facility, where you use it, and where it leaves.
For each stream, record:
- Flow rate and how much it varies
- Total suspended solids (TSS)
- Hardness, pH, and temperature
- Oils, metals, and other contaminants
- Current destination
Variability matters as much as averages. A stream that spikes during cleaning cycles or storm events needs a different design than a steady one.
Then confirm your data in the lab. Bench-scale and jar testing shows how your water settles, which coagulants and polymers work, and how solids dewater. Those results guide equipment selection and sizing before you commit to a design.
Step 2: Match Water Quality to Each Use
Not every use needs the same water quality. Higher quality takes more treatment, and more treatment costs more. Match the treatment level to the job.
Common reuse targets include:
- Cooling tower makeup
- Plant process water
- Boiler feed water
Water filtered to less than 1 milligram per liter (mg/L) of TSS may go directly to a cooling tower. Boiler feed water may need reverse osmosis (RO) after filtration. Start with your cleanest streams. They usually need the least treatment and deliver the quickest savings.
Step 3: Select the Treatment Approach
Your water determines the treatment, not the other way around. For water with suspended solids, a typical sequence includes:
- Chemical pretreatment with coagulant and polymer to build settleable particles
- Clarification to remove suspended solids
- Filtration to polish the clarified water
- Sludge treatment to thicken and dewater removed solids
Your TSS level helps set the starting point. As a general guide, water below 50 mg/L TSS can often go straight to filtration. Water above 500 mg/L may need a standard clarifier first. If hardness exceeds 150 mg/L as calcium carbonate (CaCO₃), consider cold lime softening to protect downstream equipment from scaling.
Clarifier choice depends on the feed. The Solids CONTACT CLARIFIER™ mixes settled solids back into the feed water. This builds larger, faster-settling particles when the feed lacks enough solids to flocculate on its own. Its overflow typically carries less than 10 mg/L of TSS. RapiSand™ Ballasted Flocculation adds sand and polymer to speed settling in a high-rate system.
Filtration follows when your use requires it. Dual media filters can bring TSS below 1 mg/L. The AltaFilter™ Ultrafiltration System removes small suspended solids and improves the efficiency of a downstream RO system.
Close the loop inside the treatment plant, too. Filter backwash and dewatering filtrate can return to the clarifier instead of leaving the system.
Step 4: Plan for the Full Equipment Lifecycle
Reuse systems run for years. Plan for how you will operate and support them from the start.
Consider these lifecycle needs:
- Start-up and commissioning support
- Operator training
- Parts and service
- Retrofit and upgrade options as your water sources and permits change
A system that fits your process today should still fit as conditions shift. That is where a long-term engineering partner adds value. Our full plant solutions cover design-build, plant maintenance and operations, and strategic partnering, so one team can support your reuse system from design through operation.
Ask These Questions Before You Invest
Reuse delivers real benefits. It lowers freshwater withdrawal, reduces discharge volume, and cuts waste. Those results depend on a design built around your process. Before you evaluate equipment, ask:
- Where does your water come from, and where does it go?
- Which uses need the highest water quality?
- What do bench-scale tests show about your water?
- Who will support the system after start-up?
Answer these first. The right treatment approach becomes much easier to see.
