| Typical Permeate Capacity | 0.5–5 m³/day | 10–100 m³/day | 100–1,000+ m³/day | Request a guaranteed permeate flow at the specified feed temperature, pressure, TDS, and recovery rate. |
| Typical Recovery Rate | 40–60% | 50–75% | 55–85%, depending on staging and concentrate management | Higher recovery lowers water waste but increases scaling risk; verify the design against feed-water chemistry. |
| Typical Salt Rejection | 95–99% | 96–99.5% | 97–99.7% with suitable membrane selection | Compare normalized membrane performance rather than relying only on a headline rejection percentage. |
| Pretreatment Configuration | Sediment filter, activated carbon, cartridge filter, optional softener | Multimedia filter, carbon filter, softener or antiscalant dosing, cartridge filtration | Engineered pretreatment, chemical dosing, microfiltration or ultrafiltration where required | The supplier should provide a feed-water test review, pretreatment design basis, and replacement schedule. |
| Recommended Wetted Materials | Food-grade plastic, PVC, or stainless steel 304 where appropriate | Stainless steel 304; stainless steel 316 for more corrosive or hygienic applications | Stainless steel 304/316, engineered piping, and corrosion-resistant components selected by water chemistry | Check material certificates, weld quality, surface finish, pressure ratings, and compatibility with cleaning chemicals. |
| Control and Monitoring | Pressure gauges, low-pressure protection, conductivity or TDS display | PLC control, high/low-pressure protection, conductivity, flow, pressure, and tank-level monitoring | PLC/SCADA integration, data logging, alarms, remote monitoring, and automatic chemical cleaning options | Confirm sensor accuracy, alarm functions, electrical standards, software access, and availability of replacement parts. |
| Membrane Cleaning System | Manual cleaning or basic flush arrangement | Clean-in-place tank and pump commonly available as an option | Dedicated clean-in-place system with chemical dosing, flushing, and documented procedures | A reliable supplier should specify cleaning chemicals, flow rates, compatible materials, and maintenance intervals. |
| Applicable Quality and Compliance Checks | Electrical safety, pressure-vessel safety, and applicable local installation requirements | ISO 9001 manufacturing controls, electrical conformity, pressure protection, and documented factory testing | Project-specific engineering documentation, risk assessment, factory acceptance testing, and applicable environmental permits | For drinking-water applications, verify relevant local requirements and whether components meet NSF/ANSI 58 or equivalent requirements. |
| Factory Testing Documents | Basic inspection checklist and operating instructions | Flow, pressure, conductivity, leakage, and electrical test records | Detailed FAT protocol, performance test data, drawings, manuals, spare-parts list, and calibration records | Do not accept certificates without checking their issuing body, scope, validity, and relationship to the supplied equipment. |
| Typical Lead Time | 3–8 weeks | 6–14 weeks | 12–28+ weeks, depending on engineering and site scope | Compare the complete delivery schedule, including design approval, fabrication, testing, shipping, installation, and commissioning. |
| Indicative Equipment-Only Budget | Approximately USD 2,000–15,000 | Approximately USD 15,000–100,000 | Approximately USD 100,000–1,000,000+ | Treat price as a total-cost comparison: include pretreatment, controls, membranes, freight, installation, commissioning, consumables, and taxes. |
| Operating Cost Drivers | Membrane and cartridge replacement, electricity, filters, and cleaning chemicals | Energy, antiscalant or softening chemicals, membrane replacement, labor, and concentrate disposal | Energy efficiency, recovery rate, chemical consumption, membrane life, labor, downtime, and concentrate treatment | Ask for a five-year lifecycle-cost model based on local electricity, water, chemical, and labor prices. |
| Warranty and Service Benchmark | 12 months for equipment is common; consumables are often excluded | 12–24 months may be offered, subject to operating conditions and maintenance records | Project warranty commonly covers equipment workmanship; performance guarantees require defined feed-water conditions | Evaluate response time, local technicians, remote diagnostics, spare-parts availability, training, and written warranty exclusions. |