Skip to main content
Library

CostingEquipment sizingEnergy mass balanceOther

Water Treatment Screening Cost, Energy & Footprint

Screening-stage estimator for water treatment plant CAPEX/OPEX, electricity use, modular unit count, and plot footprint based on water source, end use, and flow.

Photo of alexi

alexi

I do low-carbon energy stuff for 10 years & build things I wish existed.

2

Inputs

Used to pick screening defaults for specific energy use and reference CAPEX.

Used to adjust treatment stringency defaults (CAPEX and chemicals).

Nameplate treated water output at design conditions.

min 50 · max 20000 · step 50 · m3/day

Fraction of the year the plant operates at average design throughput (accounts for downtime and partial operation).

Blended power price paid by the plant (energy + supply where appropriate).

EUR/MWh

Used for annualizing CAPEX via capital recovery factor (CRF).

ratio

Economic life used for CRF-based annualization.

years

KPIs

Levelized cost of treated water

Total annual cost divided by annual treated volume

…EUR/m3

Installed plant cost (installed CAPEX)

Equipment purchase × installation factor; excludes owner costs unless embedded

…EUR
Levelized water cost evolution

Log in to view this sensitivity chart.

Results - Design

Flows & footprints

Annual treated water production

Net production based on capacity factor (utilization)

…m3/year

Average electrical demand at load

Annual kWh divided by operating hours

…kW

Number of modular treatment trains

Rounded up to meet design capacity

…count

Equalization/buffer tank volume

Simple hours-of-storage basis

…m3

Equalization tank diameter (approx.)

Assumes vertical cylinder and fixed liquid height

…m

Estimated plot space requirement

Process footprint × integration factor

…m2

Results - Capex

Equipment cost: Main treatment (core process skids)

Allocated fraction of equipment purchase CAPEX

…EUR

Equipment cost: Pretreatment

Allocated fraction of equipment purchase CAPEX

…EUR

Equipment cost: Post-treatment & disinfection

Allocated fraction of equipment purchase CAPEX

…EUR

Equipment cost: Controls, electrical & instrumentation

Allocated fraction of equipment purchase CAPEX

…EUR

Equipment purchase cost (EPC excl.)

Purchase cost only; excludes installation and indirects

…EUR

Equipment cost: Intake & raw water pumping

Allocated fraction of equipment purchase CAPEX

…EUR

Installed plant cost (installed CAPEX)

Equipment purchase × installation factor; excludes owner costs unless embedded

…EUR

Results - Opex

Annual fixed O&M cost

Maintenance/labor/overheads proxy (excludes electricity, chemicals, replacements)

…EUR/year

Annual membrane/media replacement cost

Variable OPEX as fraction of main-treatment equipment

…EUR/year

Annual chemicals & consumables cost

Variable OPEX scaled by treated volume

…EUR/year

About

Calculator context

Introduction

This calculator provides a pre-feasibility (screening) estimate of water treatment plant costs (CAPEX/OPEX), power consumption, annual treated water production, and plot-space footprint using only inputs a business developer typically knows early: water source, intended use, design flow, electricity price, capacity factor, and financing assumptions. It is intended for rapid option screening and order-of-magnitude comparisons for Technology: other treatment configurations.

Methodology follows common early-phase practices used across water infrastructure and energy project screening: (i) power-law scaling for equipment cost with capacity, (ii) installed-cost factors (Lang-factor style) to move from equipment purchase to installed plant cost, and (iii) annualization via CRF to compute a levelized cost per unit output. Default reference values are informed by publicly available synthesis sources and cost-method conventions (e.g., IRENA/IEA costing frameworks, NREL desalination and water-treatment energy intensities, and sector handbooks such as AWWA/WEF guidance).

Methodology

Key steps and equations (variables defined in-line):

  • Capacity & utilization

    • load_hours = hours_per_year * capacity_factor
    • annual_production_m3_year = (treatment_flow_m3_day / hours_per_day) * load_hours

  • Energy use with part-load penalty

    • load_penalty = clamp(1 + penalty_coeff * (1 - capacity_factor), 1, max_penalty)
    • effective_consumption_kwh_m3 = specific_consumption_kwh_m3 * load_penalty
    • annual_electricity_kwh = annual_production_m3_year * effective_consumption_kwh_m3

  • Costing (screening scale-up + breakdown)

    • specific_capex_scaled = clamp(specific_capex_ref * (capacity/cap_ref)^capex_scale_exponent, capex_min, capex_max)
    • capex_equipment_purchase = specific_capex_scaled * capacity
    • capex_installed = capex_equipment_purchase * install_factor
    • Equipment purchase CAPEX is split into major sub-systems (intake, pretreatment, main treatment, post-treatment, controls) using fixed fractions.

  • Annualization & levelized cost

    • CRF = (r*(1+r)^n)/((1+r)^n-1) with a guard on the denominator
    • annualized_capex = capex_installed * CRF
    • total_annual_cost = annualized_capex + fixed_O&M + electricity + chemicals + membrane_replacement
    • levelized_cost_eur_per_m3 = total_annual_cost / annual_production_m3_year

Applications

  • Business development: compare surface vs groundwater vs seawater/brackish projects and quantify the effect on EUR/m3 and MWh/year before committing to detailed engineering.
  • Owner/utility screening: evaluate how capacity factor and electricity price shift OPEX dominance and identify when energy efficiency upgrades are most valuable.
  • Early layout planning (EPC/pre-FEED): estimate number of modular trains, equalization tank sizing, and plot area to confirm site feasibility and integration needs.

Model

96 variables — inputs, calculations and outputs, with their dependencies.

96 variables shown of 96
VariableValueUnitDepends on
1——
1——
1000m3/day—
90%—
120EUR/MWh—
0.08ratio—
20years—
VariableFormulaUnitDepends on
if((if(<=0,1,0)+if((*0.01)<=0,1,0)+if((*0.01)>1,1,0)+if(<0,1,0)+if(<0,1,0)+if(<=0,1,0)+if(<1,1,0)+if(>3,1,0)+if(<1,1,0)+if(>3,1,0))>0,1,0)bool
m3/day
/max(,)m3/day
*(*0.01)h/year
clamp(1+*(1-(*0.01)),1,)—
if(==1,,if(==2,,))kWh/m3
if(==1,,if(==2,,))—
*kWh/m3
*kWh/m3
/max(,)m3/h
*kWh/year
if(==1,,if(==2,,))EUR/(m3/day)
if(==1,,if(==2,,))—
clamp(,,)EUR/(m3/day)
*(/max(,))^—
clamp(,,)—
if(==1,,if(==2,,))EUR/m3
+++EUR/year
(*(1+)^)/max(((1+)^-1),)—
EUR
*(^2)/m2
*+m2
VariableFormulaUnitDepends on
ceil(/max(,))count
**(*0.01)/max(,)m3/year
/max(,)MWh/year
*EUR/year
**(/max(,))^(-1)EUR/(m3/day)
*EUR
*EUR
*EUR
*EUR
*EUR
*EUR
*EUR
*EUR/year
*EUR/year
*EUR/year
*EUR/year
+EUR/year
/max(,)EUR/m3
*m3
sqrt((*)/(**max(,)))m
*m2
/max(,)kW

Assumptions

45 assumptions used in the calculations

  • Prevents division-by-zero and unstable behavior at extreme/invalid inputs.

    0.000001
    Numerical stability constant for division guards

  • Used to convert capacity factor into annual operating hours.

    Market range 8760

    8760h/year
    Calendar year hours

  • Used where daily capacity is the base unit.

    365day/year
    Calendar year days

  • Converts m3/day to m3/h for load-hour calculations.

    Market range 24

    24h/day
    Time conversion constant

  • Converts kWh to MWh for reporting and costing.

    Market range 1000

    1000kWh/MWh
    Energy unit conversion

  • Tank area/diameter geometry.

    Market range 3.14159

    3.141593
    Mathematical constant

  • Used in cylinder diameter back-calculation from volume.

    Market range 4

    4
    Geometry helper constant

  • Defines the anchor point for specific CAPEX and O&M scaling.

    1000m3/day
    Reference capacity for scaling laws

  • Captures decreasing specific CAPEX with capacity at screening level.

    0.65
    Economies-of-scale exponent (power-law)

  • Prevents unrealistically low specific CAPEX when scaling to very large plants.

    200EUR/(m3/day)
    Lower clamp on specific CAPEX

  • Prevents unrealistically high specific CAPEX for very small plants or extreme scaling.

    5000EUR/(m3/day)
    Upper clamp on specific CAPEX

  • Screening reference for conventional treatment with moderate pretreatment requirements.

    900EUR/(m3/day)
    Reference equipment purchase CAPEX (surface water baseline)

  • Often lower solids/turbidity reduces pretreatment scope at screening level.

    700EUR/(m3/day)
    Reference equipment purchase CAPEX (groundwater baseline)

  • Higher-pressure desalination trains and pretreatment increase equipment cost.

    1800EUR/(m3/day)
    Reference equipment purchase CAPEX (seawater/brackish baseline)

  • Higher polishing/disinfection and compliance requirements increase CAPEX.

    1.15
    End-use multiplier (potable)

  • Baseline multiplier for general industrial utility/process water at screening level.

    1
    End-use multiplier (industrial)

  • Often less stringent than potable, reducing polishing scope.

    0.85
    End-use multiplier (irrigation)

  • Approximates installation labor, piping, electrical, civil integration, and contractor overheads.

    1.75
    Installed-cost factor applied to equipment purchase cost

  • Represents labor/maintenance/overheads excluding explicitly modeled variable OPEX items.

    0.04
    Reference fixed O&M fraction of installed CAPEX

  • Allows fixed O&M fraction to decrease mildly with scale.

    -0.1
    O&M economies-of-scale exponent

  • Prevents unrealistically low fixed O&M at large scale.

    0.02
    Lower clamp on fixed O&M fraction

  • Caps fixed O&M fraction for very small plants / extreme scaling.

    0.08
    Upper clamp on fixed O&M fraction

  • Captures reduced efficiency at lower utilization (auxiliaries, cycling, suboptimal operation).

    0.2
    Part-load energy penalty coefficient

  • Prevents excessive penalty escalation at low capacity factor.

    1.3
    Maximum part-load energy multiplier

  • Represents typical pumping + filtration/disinfection energy at screening level.

    0.5kWh/m3
    Baseline specific electricity consumption for surface water treatment

  • Often lower solids load; energy dominated by pumping and basic treatment.

    0.4kWh/m3
    Baseline specific electricity consumption for groundwater treatment

  • Represents RO/high-pressure dominated energy use at screening level.

    3.5kWh/m3
    Baseline specific electricity consumption for seawater/brackish desalination-like treatment

  • Adds modest energy for additional polishing/disinfection and tighter process control.

    1.1
    Energy multiplier for potable use

  • Neutral baseline at screening stage.

    1
    Energy multiplier for industrial use

  • Lower polishing needs can reduce treatment energy at screening level.

    0.9
    Energy multiplier for irrigation use

  • Coagulants, pH adjustment, disinfectant, minor consumables at screening level.

    0.08EUR/m3
    Chemicals/consumables unit cost (potable)

  • Moderate chemical consumption for general industrial water conditioning.

    0.05EUR/m3
    Chemicals/consumables unit cost (industrial)

  • Lower chemical demand at screening level for less stringent quality targets.

    0.03EUR/m3
    Chemicals/consumables unit cost (irrigation)

  • Captures periodic replacement averaged as an annual fraction of main-treatment equipment cost.

    0.061/year
    Replacement fraction for main-treatment media/membranes

  • Provides sub-system purchase cost breakdown consistent with a typical modular plant.

    0.12
    Equipment CAPEX fraction allocation: intake & raw pumping

  • Represents screens/DAF/filters/UF front-end depending on source quality.

    0.18
    Equipment CAPEX fraction allocation: pretreatment

  • Core process skids often dominate purchase cost in modular plants.

    0.45
    Equipment CAPEX fraction allocation: main treatment (core process)

  • Includes remineralization/pH adjustment/disinfection and finishing.

    0.15
    Equipment CAPEX fraction allocation: post-treatment

  • Provides a screening share for PLC/SCADA/instrumentation and MCC components included in purchase scope.

    0.1
    Equipment CAPEX fraction allocation: controls & E&I

  • Defines how many parallel units are required for the plant design flow.

    500m3/day
    Reference modular train capacity

  • Used to estimate process area and plot space at screening level.

    20m2
    Footprint per modular train (process skid)

  • Provides buffering for feed variability and operational stability at screening stage.

    4h
    Equalization/storage hours

  • Enables diameter back-calculation from volume for early layout.

    6m
    AI

  • Accounts for freeboard and operational headspace.

    0.85
    Operating fill fraction for tank sizing

  • Accounts for access ways, pipe racks, electrical rooms, laydown, and maintainability clearance.

    1.8
    Plot-space multiplier over process equipment footprint