RRR
1000 LPH Reverse Osmosis (RO) Plant
Industrial / Commercial RO system — pre-treatment, membrane trains, recovery control, CIP and skid-mounted options. Designed for reliable permeate quality and easy operation.
Quick Summary
Rated capacity: 1000 LPH (1,000 litres per hour). Typical application: mineral water, boiler feed/pretreatment, tertiary polishing, manufacturing processes. Typical feed: groundwater / surface water / treated ETP permeate. Final permeate quality depends on feed TDS, RO stages & recovery.
Process Flow (Typical)
Raw feed → Multimedia / Pressure Sand Filter → Activated Carbon Filter → Water Softener / Anti-scalant dosing → Cartridge (5 µm) → High-Pressure Pump → RO Skid (Stage 1 → Stage 2 optional) → Permeate Tank → Post-treatment (UV / Hypo if required) → Distribution.
Pre-treatment must be sized to protect membranes: turbidity, organics and hardness removal are critical. Anti-scalant and pH control frequently required.
Design Basis & Digit-by-Digit Calculations
Given / Assumed:
Plant flow (permeate) = 1000 LPH = 1,000 L/hr.
Convert to m³/hr: 1,000 ÷ 1,000 = 1.000 m³/hr.
Convert to m³/day (for daily accounting): 1.000 × 24 = 24.000 m³/day.
Typical RO design recovery (single-pass) = 70% (common for brackish water); use 70% unless feed TDS is very high — adjust as needed.
Plant flow (permeate) = 1000 LPH = 1,000 L/hr.
Convert to m³/hr: 1,000 ÷ 1,000 = 1.000 m³/hr.
Convert to m³/day (for daily accounting): 1.000 × 24 = 24.000 m³/day.
Typical RO design recovery (single-pass) = 70% (common for brackish water); use 70% unless feed TDS is very high — adjust as needed.
Feed & Reject Flow (digit-by-digit)
Let R = recovery = 0.70 (70%). Permeate P = 1.000 m³/hr.
Feed Q_f = P / R = 1.000 ÷ 0.70 = 1.428571... m³/hr.
Compute carefully: 1.000 ÷ 0.70 = 1.4285714286 → round to 1.429 m³/hr (approx).
Reject (concentrate) Q_r = Q_f − P = 1.428571... − 1.000 = 0.428571... m³/hr ≈ 0.429 m³/hr.
In litres/hour: Feed = 1.429 × 1000 = 1,429 LPH; Reject = 429 LPH; Permeate = 1000 LPH.
Feed Q_f = P / R = 1.000 ÷ 0.70 = 1.428571... m³/hr.
Compute carefully: 1.000 ÷ 0.70 = 1.4285714286 → round to 1.429 m³/hr (approx).
Reject (concentrate) Q_r = Q_f − P = 1.428571... − 1.000 = 0.428571... m³/hr ≈ 0.429 m³/hr.
In litres/hour: Feed = 1.429 × 1000 = 1,429 LPH; Reject = 429 LPH; Permeate = 1000 LPH.
Given P = 1,000 L/hr = 1.000 m³/hr
Recovery R = 70% = 0.70
Q_f = P / R = 1.000 / 0.70 = 1.428571... m³/hr → 1.429 m³/hr
Q_r = Q_f - P = 1.428571... - 1.000 = 0.428571... m³/hr → 0.429 m³/hr
In LPH: Feed = 1,429 LPH, Permeate = 1,000 LPH, Reject = 429 LPH
Membrane Area & Number of Elements (Indicative)
Use conservative design flux of 15–20 LMH (litres/m²·hr) for long life — we'll use 16 LMH for calculation.
Permeate required = 1,000 L/hr = 1.000 m³/hr = 24 m³/day but use hourly flux arithmetic:
Required membrane area A = Permeate (L/hr) ÷ flux (L/m²·hr) = 1,000 ÷ 16 = 62.5 m².
Typical 8" wound element active area ≈ 6.0 m² (vendor dependent). Number of elements ≈ 62.5 ÷ 6.0 = 10.416... → round up to 11 elements.
Common practice: use 2 pressure vessels in 2 trains (e.g., 2 × 6 elements) for operational flexibility.
Permeate required = 1,000 L/hr = 1.000 m³/hr = 24 m³/day but use hourly flux arithmetic:
Required membrane area A = Permeate (L/hr) ÷ flux (L/m²·hr) = 1,000 ÷ 16 = 62.5 m².
Typical 8" wound element active area ≈ 6.0 m² (vendor dependent). Number of elements ≈ 62.5 ÷ 6.0 = 10.416... → round up to 11 elements.
Common practice: use 2 pressure vessels in 2 trains (e.g., 2 × 6 elements) for operational flexibility.
Flux = 16 L/m²·hr
A = 1,000 L/hr ÷ 16 L/m²·hr = 62.5 m²
Element area ≈ 6.0 m² → 62.5 ÷ 6.0 = 10.416... → use 11 elements (e.g., 2 vessels: 6 + 5)
Exact element area and train configuration chosen from membrane vendor (e.g., DOW, Toray) and physical vessel sizes (8" × 40" / 8" × 48").
Pre-treatment — Protect the Membranes
- Multimedia / Pressure Sand Filter (PSF) — remove turbidity & settleable solids.
- Activated Carbon Filter (ACF) — remove free chlorine & organics (protects polyamide membranes).
- Water Softener / Anti-scaling dosing — if hardness (Ca & Mg) > limit; otherwise anti-scalant dosing (recommended).
- Cartridge Filters (5 µm → 1 µm) — final particulate protection before HP pump & membranes.
- Biocide / Cleaning strategy (CIP) — periodic acid & alkali CIP to control scaling & fouling.
Pre-treatment sizing should be based on raw water report: turbidity, SDI/Foulant Index, hardness, silica, iron, manganese, organics, and chlorine.
High-Pressure Pump & Power Estimate
RO feed pressure depends on feed TDS. For brackish ~10–20 bar; for low-TDS groundwater lower pressure. We give an approximate pump power estimate for design pressure 15 bar and pump efficiency 70%.
Hydraulic power (kW) = (Q_f × ρ × g × H) / (3600 × 1000 × η) — simplified: P(kW) ≈ (Q_m³/hr × Head_m × 9.81) / (3600 × η). We'll use a practical shortcut:
Hydraulic power (kW) = (Q_f × ρ × g × H) / (3600 × 1000 × η) — simplified: P(kW) ≈ (Q_m³/hr × Head_m × 9.81) / (3600 × η). We'll use a practical shortcut:
Use approximate formula:
Q = Feed flow = 1.429 m³/hr
Convert to m³/s: 1.429 ÷ 3600 = 0.0003970 m³/s
Head (H) = Pressure (15 bar) × 10.197 = 152.955 m (approx). (15 bar × 10.197 = 152.955 m)
Hydraulic power (W) = ρ × g × Q(m³/s) × H
ρ = 1000 kg/m³ ; g = 9.81 m/s²
=> Power = 1000 × 9.81 × 0.0003970 × 152.955 ≈ 593.7 W ≈ 0.594 kW
Motor & system efficiency assumed 70% → Installed motor ≈ 0.594 ÷ 0.7 ≈ 0.849 kW → use 1.0 kW motor (min)
Note: This is an indicative calculation; vendor pump will be sized with safety & piping losses — commonly 1–3 kW for 1000 LPH depending on pressure.
Real installations often use 2 pumps (duty + standby) or a variable-speed drive for feed control and energy optimization. Confirm pressure & TDS to size pump correctly.
Membrane & Skid Details
| Item | Spec / Note |
|---|---|
| Membrane Type | Polyamide thin-film composite (TFC) — brackish water grade |
| Design Flux | 12–20 LMH (we used 16 LMH) |
| Element | 8" × 40" typical (element area ~6 m²) |
| Skid | SS304/316 frame, pressure vessels, gauges, valves, interconnect piping |
| CIP | Acid & alkali dosing pump, CIP manifold for cleaning cycles |
Expected Performance & Output
| Parameter | Feed (typical) | Permeate (expected) |
|---|---|---|
| TDS | 500 – 2000 mg/L (site dependent) | Depends on membrane rejection — typically 90–99% rejection → e.g., feed 1000 mg/L → permeate 10–100 mg/L |
| SDI | < 5 desired | Permeate low SDI |
| Permeate Flow | — | 1000 LPH (design) |
Membrane rejection and final TDS depend on feed TDS, temperature and recovery. Provide raw water TDS and temperature for exact guarantees.
Operation & Maintenance
- Monitor differential pressure across cartridge & membrane elements; schedule CIP when flux drops or TMP rises.
- Use anti-scalant dosing when hardness/silica/iron risk present.
- Keep spare elements (10–20% replacement) and spare cartridges.
- Conduct periodic membrane integrity tests and salt rejection tests.
- Maintain logbook for permeate TDS, flows, pressures and CIP events.