| name | membrane-ro-fundamentals |
| description | Reverse Osmosis (RO) and Electrodeionization (EDI) process fundamentals — formulas (recovery, rejection, NDP, osmotic pressure, TCF, NPF/NSP), authoritative standards reference (ASTM/ISO/USP/Ph.Eur./WHO/EN), vendor design windows (DuPont, Hydranautics, Toray, Suez, LANXESS), water chemistry, EDI quick reference, IT/EN glossary. Use when working on RO/EDI plant code, KPI calculations, or normative citations. |
| user-invocable | false |
RO & EDI Process Fundamentals
Reference for water-treatment expertise: formulas, normative standards, vendor design envelopes, water chemistry, and bilingual terminology.
Convention markers used throughout the membrane skills:
⚠️ — likely bug or incorrect numerical approximation in calling code; highest priority💡 — enhancement opportunity (new KPI, new model field, refined threshold)
§1 — RO Process Fundamentals
All formulas in SI (LMH, bar, °C) with US field-unit (GFD, psi, °F) variant noted. Variables: Qf feed flow, Qp permeate, Qc concentrate, Cf/Cp/Cc concentrations, Am membrane area, T temperature.
1.1 Recovery (Water Recovery / Recupero)
Y = Qp / Qf
Typical ranges (vendor-dependent):
- SWRO single-pass: 35–50 %
- BWRO: 70–85 %
- BWRO high-recovery (w/ antiscalant): 90 %+
- Double-pass RO+RO overall: 70–80 %
Source: ASTM D6161-19; DuPont 45-D01504; Hydranautics TSB 107.
1.2 Concentration Factor (CF)
CF_ideal = 1 / (1 - Y) # for R = 1
CF_real = (1 - Y·(1 - R)) / (1 - Y) # for rejection R
At Y = 0.75 and R = 0.99: CF_ideal = 4.00, CF_real ≈ 3.97 (error < 1 %), so the ideal form is acceptable for SWRO/BWRO design.
Source: DuPont 45-D01591 (Design Equations).
1.3 Salt Rejection — three definitions
| Variant | Symbol | Formula | When used |
|---|
| Observed (apparent) | R_obs | 1 − Cp/Cf | What instruments measure |
| System (log-mean) | R_sys | 1 − Cp / mean(Cf, Cc) | Standard reporting |
| Intrinsic (at wall) | R_int | 1 − Cp / (β · mean(Cf, Cc)) | Corrected for polarization |
Concentration polarization factor:
β = Cwall / Cbulk = exp(0.7 · Y_element)
where Y_element is per-element recovery. FilmTec design limit: β ≤ 1.2 → Y_element ≤ 18 % (the 18 % per-element rule). Hydranautics is more conservative at 15 %.
⚠️ A code path that confuses R_obs with R_sys will under-report rejection by 5–15 % at high recovery. Always specify which definition the calculator returns.
Sources: DuPont 45-D01591; Hydranautics Terms and Equations of RO.
1.4 Permeate Flux (Jw)
Jw = A · NDP · TCF · FF # vendor model
Jw = Qp / Am # operational
A = water permeability (LMH/bar), FF = fouling factor (0.85 design / 0.70 EOL).
Unit conversion: 1 GFD = 1.6987 LMH (≈ 1.70).
Typical design flux windows (vendor consensus):
| Application | GFD | LMH |
|---|
| SWRO open intake (SDI 3–5) | 7–9 | 12–15 |
| SWRO beach well (SDI < 2) | 8–10 | 14–17 |
| BWRO well (SDI < 3) | 14–18 | 24–30 |
| BWRO surface (SDI 3–5) | 10–14 | 17–24 |
| RO permeate / 2nd pass | 20–30 | 34–51 |
⚠️ A hard-coded flux_max = 25 LMH threshold is incorrect for SWRO (well above limit) and conservative for BWRO well (well below limit). Threshold must be water-source-aware.
Sources: DuPont 45-D01695 Rev 14 (Feb 2026); Hydranautics TSB 105; AMTA Optimum Flux Rates.
1.5 Salt Flux (Js)
Js = B · (mean(Cf,Cc) − Cp) ≈ B · mean(Cf,Cc)
Cp = Js / Jw # key inverse relation
B is temperature-dependent but pressure-independent (unlike A). At cold feed temperature, Jw drops while Js is relatively unchanged → Cp rises → permeate quality degrades. Cold-water permeate TDS spikes are explained by this relation.
Source: DuPont 45-D01591; Hydranautics Terms and Equations.
1.6 Net Driving Pressure (NDP)
NDP = (Pf + Pc)/2 − Pp − (πw − πp)
= mean_feed_pressure − permeate_pressure − osmotic_differential_at_wall
with πw = β · π_mean(Cf,Cc) (osmotic pressure at membrane wall, corrected for polarization).
Source: ASTM D4516-19a §6; DuPont 45-D01591.
1.7 Osmotic Pressure (π)
Rigorous Van't Hoff:
π = i · M · R · T # i ≈ 1.8–2.0 for NaCl
# R = 0.08314 L·bar/(mol·K)
# T in Kelvin
Engineering shortcut (industry standard at 25 °C):
π [psi] ≈ 0.0085 · TDS [ppm]
π [bar] ≈ 0.000586 · TDS [ppm]
Shortcut accuracy:
- ±3 % for NaCl-dominated brackish (1 000–10 000 ppm)
- ±5 % for seawater (32 000–40 000 ppm) — agrees with Pitzer model up to 70 g/L NaCl
- Diverges > 10 % for sulfate-rich or hardness-dominated brines — use OLI/PHREEQC instead
Seawater rule of thumb: 35 000 ppm → π ≈ 25–28 bar bulk; ≈ 32–35 bar at wall with β = 1.15.
⚠️ A formula returning π ≈ 8 bar for seawater under-estimates by 3–4× — verify constants and unit handling. The correct order of magnitude for seawater is 25–35 bar.
Source: Pitzer comparison (Tandfonline 2019); Stark-Water RO Working Principle Guide; FilmTec 45-D01591.
1.8 Temperature Correction Factor (TCF)
ASTM D4516-19a normalizes flux to a 25 °C reference. General exponential form:
TCF = exp[ Ke · (1/298 − 1/(273 + T)) ]
Membrane-chemistry constants (Hydranautics TSB 107.28 Apr 2025; FilmTec 45-D01616 Rev 10 Feb 2022):
| Membrane type | Ke | Regime |
|---|
| FilmTec BW30 / SW30 (T ≥ 25 °C) | 3 020 | Hot |
| FilmTec BW30 / SW30 (T < 25 °C) | 2 640 | Cold (flux drops faster) |
| Hydranautics CPA / ESPA | 2 500–3 480 | Element-specific (TSB 107) |
| Hydranautics SWC seawater | ~3 020 | |
Practitioner shortcut: TCF ≈ 1.03 per °C around 25 °C; doubles every ~25 °C rise.
1.9 Normalized Permeate Flow (NPF) — ASTM D4516-19a §7
NPF = Qp_meas · (NDP_std / NDP_actual) · (TCF_std / TCF_actual)
Action thresholds (industry consensus):
- NPF drop 10 % vs baseline → schedule CIP
- NPF drop 15 % → CIP mandatory
- NPF drop 30 % → autopsy / replacement evaluation
⚠️ NPF cannot be computed without a baseline. Code paths declaring NPF as a field but never populating it because calculate_kpis() receives no baseline are silently broken.
1.10 Normalized Salt Passage (NSP) — ASTM D4516-19a §8
NSP = SP_meas · (mean_C_std / mean_C_actual) · (EPF_actual / EPF_std) · (STCF_std / STCF_actual)
where SP = Cp / mean(Cf, Cc) and STCF is the salt-passage temperature factor (different exponent constant: Ks ≈ 2 200).
Action threshold: NSP rise 15 % → integrity check via ASTM D6908 VDT or ASTM D3923 leak test.
1.11 Element / Vessel / Stage / Train Hierarchy
Train (skid)
└── Stage 1 ┐ array typically 2:1 or 3:2:1
├── Pressure Vessel │
│ ├── Element 1 │ standard 8"×40" or 4"×40"
│ ├── Element 2 │ 6–8 elements per vessel
│ └── … │ typical per-vessel Y = 8–15 %
└── Stage 2 / 3 reuses concentrate as feed
Per-stage recovery rule of thumb:
- Stage 1 (8 elements, single pass): Y₁ ≈ 50 %
- 2-stage train:
Ysys = 1 − (1−Y1)·(1−Y2) ≈ 75 %
- 3-stage train: 85–90 % for high-recovery BWRO
Per-element max: Y_element ≤ 18 % (FilmTec) or ≤ 15 % (Hydranautics).
§2 — Authoritative Standards Reference
| Standard | Title | Edition | When to invoke |
|---|
| ASTM D4516-19a | Standardizing RO Performance Data | 2019 | Normalize NPF, NSP — any commissioning, surveillance, warranty claim |
| ASTM D3923 | Detecting Leaks in RO and NF Devices | 2023 (also 2018) | New-element acceptance; suspected O-ring / glue-line failure |
| ASTM D3739-19 | Calculation of the Langelier Saturation Index for RO | 2019 | CaCO₃ scaling prediction; valid for concentrate TDS 10–10 000 mg/L |
| ASTM D4582 | Stiff & Davis Stability Index | current | CaCO₃ scaling at TDS > 10 000 mg/L |
| ASTM D4194-23 | Operating Characteristics of RO and NF Devices | 2023 | Short-term (< 24 h) factory or commissioning test — not for plant design |
| ASTM D4195 | Water Analysis for RO/NF Application | 2014 (withdrawn 2023, still authoritative for scope) | Feedwater characterization scope |
| ASTM D6161-19 | Terminology for Membrane Separation | 2019 | Definitive glossary; cite to resolve term disputes |
| ASTM D4189-23 | Silt Density Index (SDI) | 2023 | Pretreatment performance benchmark (30 psi, 0.45 µm, 15 min default) |
| ASTM D6908 | Integrity Testing of Water Filtration Membrane Systems | 2025 / 2017 | VDT for RO/NF; PDT for UF/MF |
| ISO 16075-1..4 | Treated Wastewater Use for Irrigation | 2020 / 2021 | Reuse projects; -2 defines water-quality classes A–D |
| WHO GDWQ 4th ed. | Guidelines for Drinking-water Quality (+ 1st & 2nd Addenda) | 2022 | Health-based limits: As 10 µg/L, B 2 400 µg/L, F 1.5 mg/L, NO₃ 50 mg/L |
| USP <645> | Water Conductivity | current | Stage 1 limit 1.3 µS/cm @ 25 °C (uncompensated, in-line) for Purified Water |
| USP <643> | Total Organic Carbon | current | 500 ppb limit for PW and WFI; system suitability with sucrose + 1,4-benzoquinone |
| Ph. Eur. 0008 | Purified Water (Aqua purificata) | current | Equivalent to USP PW; conductivity ≤ 4.3 µS/cm @ 20 °C, TOC ≤ 0.5 mg/L |
| Ph. Eur. 0169 | Water for Injection | Effective 1 April 2017 (Suppl. 9.1) | Allows non-distillation WFI via RO + EDI/UF/NF (note: no 2026 enforcement deadline for this monograph) |
| Ph. Eur. ch. 2.2.44 | TOC in Water for Pharmaceutical Use | Effective 1 July 2026 | New harmonized USP/Ph.Eur. method; CRS replaces sucrose/1,4-BQ; updates to "Water" terminology |
| EN 1717:2025 | Protection of Potable Water from Backflow | 2025 | Fluid categories 1–5; air gaps for RO permeate re-entering potable mains |
| EN 12952-12 | Boiler-feed and Boiler-water Quality | current | Tiered limits keyed to drum pressure class |
| 21 CFR Part 11 | Electronic Records & Signatures (US FDA) | — | Data integrity for pharma roadmap |
| EU Annex 11 | Computerised Systems (EudraLex Vol. 4) | — | Risk-based validation; ALCOA+ |
| SEMI F63 | Ultrapure Water for Semiconductor Processing | 2021 | ≥ 18.2 MΩ·cm, TOC < 1 ppb, SiO₂ < 0.3 ppb |
⚠️ ASTM D4195 is withdrawn (2023) but still cited as authoritative for scope — flag this explicitly when referencing.
⚠️ Ph. Eur. 0169 has no "mandatory 2026-07" deadline. The non-distillation WFI revision took effect 1 April 2017. The 2026-07 date belongs to chapter 2.2.44 (TOC harmonization), which is a different normative artifact.
§3 — Vendor Design Guides
3.1 DuPont FilmTec
Key documents: 45-D01504 (master Tech Manual); 45-D01580 (System Design); 45-D01588 (4"/midsize); 45-D01695 Rev 14 Feb 2026 (8" Design Guidelines, current); 45-D01591 (Design Equations); 45-D01616 (Plant Performance Normalization).
| Family | Use | Test conditions | Salt rejection |
|---|
| SW30HR / SW30HRLE-440i | Seawater | 32 000 ppm NaCl, 800 psi, 25 °C, 8 % | 99.7–99.8 % |
| BW30-400 / BW30HR-440i | Brackish | 2 000 ppm NaCl, 225 psi, 25 °C, 15 % | 99.5 % |
| LE / XLE / Eco | Low-energy brackish | 500–2 000 ppm, 100–150 psi | 99.0–99.4 % |
3.2 Hydranautics (Nitto)
TSB index (publicly available at membranes.com):
| TSB | Topic |
|---|
| 100 | Foulant identification |
| 105 | Storage and preservation |
| 107.28 (Apr 2025) | Foulants & cleaning procedures; TCF constants |
| 108 | Chlorination / dechlorination |
| 110 | Operating limits & biocides |
| 111 | Biofouling control |
| 113 | ESPA/CPA/SWC product specs; oxidation |
| 124 | Integrity and VDT |
| 207 | Standardization (Hydranautics version of D4516) |
| 414 | Caustic / acid CIP procedure |
| Family | Type | Notes |
|---|
| SWC4 / SWC5 / SWC6 | Seawater | 99.8 % rejection; ~92 % B rejection @ pH 8 |
| CPA3 / CPA5-LD / CPA7 | Brackish high rejection | Low-ΔP variants for fouling |
| ESPA1 / ESPA2 / ESPA4 | Energy saving | Low pressure, tap/municipal |
| PRO-XS / PRO-XR | Industrial | Lifecycle / robustness |
3.3 Toray, Suez/Veolia, LANXESS
| Vendor | Series | Notes |
|---|
| Toray | TM820V/M (seawater), TMG20D (brackish low-energy), TM720D (tap) | TM820V-400: 99.8 % @ 32 000 ppm, 800 psi |
| Suez/Veolia | AG / AK / AD / AE; GenGard antiscalant | AG8040F: ~11 000 GPD, 99.5 % |
| LANXESS | Lewabrane B400 HR / B440 HR / ULP / ASD | B400 HR: 37.9 m³/d, 99.7 % rejection |
| LG Chem | NanoH2O | Variable operating windows |
3.4 Universal vendor envelope (all polyamide TFC)
| Parameter | Limit | Damage mode if exceeded |
|---|
| Max pressure SWRO | 83 bar (1 200 psi) | Compaction; glue-line failure |
| Max pressure BWRO | 41 bar (600 psi) | Same |
| Max ΔP per element | 1 bar (15 psi) | Telescoping |
| Max ΔP per vessel | 3.5 bar (50 psi) | Same |
| Max temperature | 45 °C continuous; 35 °C above pH 10 | Compaction, hydrolysis |
| pH range continuous | 2–11 | Hydrolysis outside |
| pH range CIP | 1–13 (short-term) | |
| Free chlorine | < 0.1 ppm (effectively zero) | Oxidative attack |
| Other oxidants (O₃, MnO₄⁻, peroxide) | Not tolerated | Same |
| Max SDI₁₅ feed | 5 (3 preferred) | Colloidal fouling |
| Max turbidity feed | 1 NTU | |
§4 — Water Chemistry Essentials
4.1 Conductivity / TDS quick reference (25 °C)
| Water type | TDS (mg/L) | Conductivity (µS/cm) |
|---|
| Seawater (open ocean) | 32 000–38 000 | 50 000–58 000 |
| Mediterranean / Red Sea | 38 000–43 000 | 58 000–65 000 |
| High brackish | 5 000–15 000 | 7 000–22 000 |
| Low brackish / well | 1 000–5 000 | 1 500–7 500 |
| Tap (municipal) | 100–500 | 150–750 |
| 1st-pass RO permeate (SW feed) | 200–500 | 300–800 |
| 1st-pass RO permeate (BW feed) | 10–50 | 15–80 |
| 2nd-pass RO permeate | 1–5 | 1.5–8 |
| Mixed-bed DI / EDI product | < 0.1 | < 0.1 |
| USP PW limit (Stage 1) | — | ≤ 1.3 |
| 18.2 MΩ·cm UPW | < 0.06 | 0.055 (theoretical limit) |
Conversion rule (NaCl-dominated): TDS [ppm] ≈ 0.64 × κ [µS/cm] for brackish; 0.55–0.70 for seawater.
4.2 Typical seawater ion composition (mg/L)
| Ion | Atlantic | Mediterranean | Red Sea |
|---|
| Na⁺ | 10 800 | 12 700 | 13 500 |
| Cl⁻ | 19 400 | 22 900 | 24 100 |
| SO₄²⁻ | 2 700 | 3 200 | 3 400 |
| Mg²⁺ | 1 290 | 1 480 | 1 590 |
| Ca²⁺ | 410 | 470 | 510 |
| K⁺ | 390 | 470 | 500 |
| HCO₃⁻ | 142 | 150 | 165 |
| Br⁻ | 67 | 76 | 80 |
| Sr²⁺ | 8 | 9 | 13 |
| B (total) | 4.5 | 5.2 | 6.5 |
| TDS | 35 200 | 41 500 | 44 000 |
4.3 pH effects on rejection (pKa-driven)
| Species | pKa @ 25 °C | Practical impact |
|---|
| Boron (H₃BO₃ ⇌ B(OH)₄⁻) | 9.14–9.24 | 85–92 % @ pH 8 → > 98 % @ pH 10.5. Double-pass with high-pH 2nd pass is the industry standard for SWRO boron removal |
| Silica (H₄SiO₄ ⇌ H₃SiO₄⁻) | 9.84 | Higher pH → higher rejection but raises scaling risk |
| Ammonia (NH₄⁺ ⇌ NH₃) | 9.25 | Below pKa: 95 % rejection; above pKa: NH₃ passes (DW concern) |
| CO₂ / HCO₃⁻ / CO₃²⁻ | 6.35 / 10.33 | At pH < 7 dominated by CO₂ which passes freely; dose NaOH after RO to convert to HCO₃⁻ before EDI |
4.4 SDI interpretation (ASTM D4189-23)
| SDI₁₅ | Interpretation | Action |
|---|
| < 1 | Excellent | Years between fouling events |
| 1–3 | Acceptable | Months between CIP |
| 3–5 | Marginal | Frequent CIP likely; consider UF |
| > 5 | Unacceptable | UF / coagulation / multimedia required |
Caveat: SDI is filter-brand-dependent; Modified Fouling Index (MFI) is more rigorous.
4.5 Free chlorine / ORP
- Polyamide TFC tolerance: < 0.1 ppm free Cl₂ continuous
- ORP target after dechlorination: < 200 mV at RO inlet (some specs < 150 mV)
- SBS (sodium bisulfite) dosing: 1.46 mg per mg Cl₂ stoichiometric; practical 1.8–3.0 mg/mg (1.5–2.5× excess)
- Cumulative dose damage tracked in ppm·h — see
membrane-troubleshooting §3
4.6 Scaling indices
LSI (Langelier) — for TDS < 10 000 mg/L (ASTM D3739-19):
LSI = pH_actual − pH_s
pH_s = (9.3 + A + B) − (C + D)
A = f(TDS)
B = f(T)
C = f(Ca²⁺ hardness)
D = f(alkalinity)
LSI > 0 → CaCO₃ scaling tendency. Target: LSI(concentrate) < 0 without antiscalant; < +1.8 with effective inhibitor; up to +2.5 with strong dosing.
S&DSI (Stiff & Davis) — for TDS > 10 000 mg/L (ASTM D4582):
S&DSI = pH − pK2 + pKs − p[Ca²⁺] − p[HCO₃⁻]
Same interpretation as LSI; targets typically < +1.0 with antiscalant.
⚠️ Saturation indices must be computed at the concentrate (last element), not feed — the concentrate is where supersaturation actually occurs.
§5 — EDI Quick Reference
5.1 EDI feed envelope
| Parameter | Target | Hard limit |
|---|
| Conductivity / FCE | < 30 µS/cm preferred | < 40 µS/cm |
| Total hardness (as CaCO₃) | < 1 ppm | < 2 ppm (softener required above) |
| Total CO₂ (CO₂ + HCO₃⁻ + CO₃²⁻) | < 5 ppm | < 10 ppm (NaOH dosing / degasser) |
| Silica (SiO₂) | < 0.5 ppm | < 1 ppm |
| TOC | < 0.5 ppm | < 1 ppm |
| Fe / Mn | < 0.01 ppm each | < 0.05 ppm |
| Free chlorine | < 0.02 ppm | (destroys resin) |
| Temperature | 10–40 °C standard; 60 °C HWS modules | 5–45 °C |
| Inlet pressure | ≤ 7 bar (100 psi) | mechanical limit |
5.2 EDI product targets by application
| Application | Conductivity | Resistivity | Standard |
|---|
| Pharma PW | ≤ 1.3 µS/cm @ 25 °C | ≥ 0.77 MΩ·cm | USP <645> Stage 1 |
| Pharma WFI | ≤ 1.3 µS/cm + TOC ≤ 0.5 ppm + endotoxin ≤ 0.25 EU/mL | — | Ph. Eur. 0169 / USP WFI |
| Power-plant UPW | 0.1–1 µS/cm | 1–10 MΩ·cm | ASME / EPRI |
| Semiconductor UPW | < 0.055 µS/cm | 18.18 MΩ·cm (theoretical) | SEMI F63 |
5.3 Feed Conductivity Equivalent (FCE)
The manufacturer-standard load metric for EDI sizing — combines conductivity with the ionic load contributed by weak acids when ionized inside the stack:
FCE [µS/cm] = κ + 2.79 · CO₂[ppm] + 1.94 · SiO₂[ppm]
where:
κ = measured feed conductivity (µS/cm)CO₂ = total carbonate (CO₂ + HCO₃⁻ + CO₃²⁻) as ppm CO₂SiO₂ = total silica (reactive + colloidal)
Target: FCE 1–5 µS/cm for two-pass RO + EDI to UPW; FCE ≤ 40 µS/cm is the EDI feed limit (stack-dependent 25–43).
⚠️ Coefficient note: some methodologies use 2.66 for CO₂; 2.79 is the SnowPure/E-Cell convention — pick one and be consistent.
💡 EDI alerts that compare against raw feed_conductivity miss CO₂/SiO₂ load and silently allow off-spec operation. Always compute FCE.
§6 — Bilingual IT/EN Glossary
6.1 Process KPIs
| EN | IT | Note |
|---|
| Recovery | Recupero (Y) | Fraction or %, never raw flow |
| Rejection | Reiezione (R) | Three flavors: observed / system / intrinsic |
| Salt passage (SP) | Passaggio salino | SP = 1 − R |
| Permeate flux | Flusso del permeato (Jw) | LMH (EU) / GFD (US) |
| Salt flux | Flusso salino (Js) | Sets Cp at given Jw |
| Net Driving Pressure (NDP) | Pressione netta motrice | Apply gauge pressures consistently |
| Concentration factor (CF) | Fattore di concentrazione | 1/(1−Y) shortcut |
| Specific energy consumption (SEC) | Consumo energetico specifico | kWh/m³ |
| Normalized permeate flow (NPF) | Portata permeato normalizzata | ASTM D4516 |
| Normalized salt passage (NSP) | Passaggio salino normalizzato | ASTM D4516 |
| Temperature correction factor (TCF) | Fattore di correzione temperatura | Exponential form, Ke per membrane |
| Concentration polarization (β) | Polarizzazione di concentrazione | Wall/bulk ratio |
| Differential pressure (ΔP) | Perdita di carico | Per element / vessel / stage |
6.2 Phenomena
| EN | IT |
|---|
| Fouling | Sporcamento / fouling |
| Scaling | Incrostazione |
| Biofouling | Bioincrostazione |
| Compaction | Compattazione |
| Concentration polarization | Polarizzazione di concentrazione |
| Breakthrough | Sfondamento / breakthrough |
| Hydrolysis | Idrolisi |
| Oxidation | Ossidazione |
| Telescoping | Telescopamento (anglicismo accettato) |
| Channeling | Channeling (anglicismo) |
6.3 Components
| EN | IT |
|---|
| Skid | Skid / pacchetto pre-assemblato |
| Train | Treno (impianto) |
| Element (membrane element) | Elemento (a membrana) |
| Pressure vessel (PV) | Recipiente in pressione |
| Stage | Stadio |
| Pass | Passaggio |
| Feed spacer | Spaziatore di feed |
| Permeate channel / carrier | Canale del permeato |
| Header / manifold | Collettore |
| Energy Recovery Device (ERD) | Recuperatore di energia (Pelton / PX / DWEER) |
| High-pressure pump (HPP) | Pompa di alta pressione |
| Booster pump | Pompa di rilancio |
| Antiscalant | Antincrostante / antiscalante |
| Dechlorinator (SMBS) | Dechlorante / metabisolfito di sodio |
| Cartridge filter | Filtro a cartuccia |
6.4 Operations
| EN | IT |
|---|
| CIP (Cleaning In Place) | Lavaggio in posto / CIP |
| Flushing | Lavaggio / flussaggio |
| Sanitization | Sanitizzazione |
| Standby / preservation | Conservazione / messa in standby |
| Set-point | Set-point / valore di consegna |
| Trip / shutdown | Arresto di emergenza |
| Commissioning | Messa in servizio |
| Performance test | Test di prestazione |
| Autopsy | Autopsia (membrana) |
| Ramp-up | Avviamento progressivo (≤ 0.7 bar/s) |
6.5 Regulatory
| EN | IT |
|---|
| Purified Water (PW) | Acqua purificata |
| Water For Injection (WFI) | Acqua per preparazioni iniettabili |
| Highly Purified Water (HPW) | Acqua altamente purificata (Ph. Eur. historical) |
| Drinking water | Acqua potabile / per consumo umano |
| Reclaimed water | Acqua riutilizzata / di riuso |
| Endotoxin | Endotossina (EU/mL; LAL test) |
| Bioburden | Carica microbica (CFU/mL) |
| Total Organic Carbon (TOC) | Carbonio organico totale |
Sources
Primary normative — ASTM D4516-19a, D6161-19, D4189-23, D3739-19, D4582, D3923, D4194-23, D6908; ISO 16075-1..4; USP <645>, <643>; Ph. Eur. 0008, 0169 (Suppl. 9.1 effective 2017-04-01), chapter 2.2.44 (effective 2026-07-01); WHO GDWQ 4th ed. (2022 + addenda); EN 1717:2025; EN 12952-12; 21 CFR Part 11; EU Annex 11; SEMI F63:2021.
Vendor manuals — DuPont FilmTec 45-D01504, 45-D01580, 45-D01588, 45-D01591, 45-D01616, 45-D01695 (Rev 14 Feb 2026); Hydranautics TSB 100, 105, 107.28 (Apr 2025), 108, 110, 111, 113, 124, 207, 414; Toray RO Brochure 2024; LANXESS Lewabrane datasheets; LG Chem NanoH2O.
Reference — Lenntech RO chemistry pages; Stark-Water RO Working Principle; Pitzer vs Van't Hoff comparison (Tandfonline 2019); EMA Q&A on non-distillation WFI; PharmOut on Ph. Eur. 0169 (2017); FDCELL on chapter 2.2.44 (2026-07).
