1000 LPH Water Softener Plant
Flow = 1000 LPH (1.0 m³/hr). Typical configuration: raw water → sand/cartridge prefilter (if required) → cation exchange softener (Na⁺ form) → brine/regeneration system → treated soft water buffer. This page shows indicative design calculations and sizing — final design depends on raw feed hardness, flow profile and regeneration schedule.
Process Flow
Design Basis & Calculations (digit-by-digit)
Plant Flow Q = 1000 LPH = 1,000 L/hr.
Convert to m³/hr: 1,000 ÷ 1,000 = 1.000 m³/hr.
Operating profile = continuous service (24/7) or cyclic (specify); design for peak 1.0 m³/hr.
Resin Volume (approximation)
Calculation:
Resin volume V (m³) = Q (m³/hr) ÷ service_velocity (m/hr).
Q = 1.000 m³/hr. Service velocity = 10 m/hr.
V = 1.000 ÷ 10 = 0.100 m³ (that is 100 litres of resin).
Vessel Area & Diameter (worked example)
Required cross-sectional area A = V ÷ bed_depth = 0.100 ÷ 0.8 = 0.125 m².
Area A = 0.125 m². Convert area to diameter:
Diameter d = √(4 × A / π).
Compute stepwise:
4 × A = 4 × 0.125 = 0.500.
π ≈ 3.1416.
(4 × A) ÷ π = 0.500 ÷ 3.1416 ≈ 0.159155.
d = √0.159155 ≈ 0.39894 m → ≈ 399 mm.
Practical vessel choice: use a standard vessel of **450 mm or 500 mm diameter** (FRP/SS) to give margin and reduce service velocity; recommended: **500 mm dia × bed depth 800–900 mm** for robust operation.
Backwash Flow Calculation
Using A = 0.125 m² (from above), backwash flow Q_bw = A × v_bw = 0.125 × 50 = 6.25 m³/hr = 6,250 L/hr.
Backwash pump sizing: recommend pump ≥ 7 m³/hr at appropriate head (duty + margin). Provide backwash tank or reuse blowdown to drain as per site.
Regeneration (Brine) — Practical Details
Resin volume = 0.100 m³ → Salt required per regeneration = 10 × 0.100 = 1.0 kg NaCl.
Brine tank: To allow multiple regenerations and ease of operation, recommend storing **50 – 100 kg** of salt (one 50 kg bag) and brine preparation tank sized ≈ 200 – 300 L.
Regeneration frequency depends on raw hardness (mg/L as CaCO₃) and service flow hours. Example: for raw hardness 300 mg/L CaCO₃, resin capacity & run length must be calculated — provide raw hardness to get exact regen interval & salt consumption estimate.
Equipment List (Scope of Supply)
- Softener vessel FRP/SS (≥500 mm dia recommended) with multiport valve (manual / automatic) — 1 set
- Cation exchange resin (strong acid, Na⁺ form) — 100 L (0.1 m³)
- Raw water inlet pump (if required) and treated water transfer pump
- Brine preparation tank & dosing valve + salt storage (50–100 kg capacity)
- Backwash pump (≈ 7 m³/hr) for media cleaning
- Pressure gauges, sample points, valves, flow meter
- Control panel (timer / PLC for regeneration) and level switches
- Pre-filtration (PSF or cartridge) recommended if turbidity > 10 NTU
- Installation piping, commissioning & spares kit (valve seals, sample cartridges)
Expected Performance
| Parameter | Typical Inlet | Expected Outlet (Softened) |
|---|---|---|
| Hardness (as CaCO₃) | Varies (e.g., 100 – 1000 mg/L) | < 5 – 10 mg/L (depending on set point) |
| Iron | May be present | Partial removal; pre-oxidation / filter recommended if Fe > 1 mg/L |
| Turbidity | 0 – 50 NTU | < 1 NTU (after prefilter) |
| pH | 6.5 – 8.5 | 6.5 – 8.5 (no large change) |
Exact outlet hardness & salt consumption require raw water report (hardness mg/L, iron, turbidity, TDS) and desired soft water set point.
Operation & Maintenance
- Backwash frequency: daily/weekly depending on raw solids load. Monitor headloss across bed.
- Regeneration: automatic cycles (timer or meter-based). Monitor brine concentration.
- Keep spare resin (10%) and critical spare parts: valve seals, brine injector, backwash pump.
- Record log of regenerations, salt usage, and water hardness checks (weekly initially).
- Protect softener from chlorine (dechlorinate) if downstream resin sensitive — check resin type.