ErgoPlanner

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Design Standards ​

Industry standards and design criteria reference

Overview ​

ErgoPlanner incorporates design criteria from major international standards. This reference summarizes key design parameters.

UK Water Industry Standards ​

Sewers for Adoption (8th Edition) ​

ParameterRequirement
Minimum gradient (100mm)1:80
Minimum gradient (150mm)1:150
Minimum velocity0.75 m/s at 1/3 full
Maximum velocity3.0 m/s

Design Flow Multiples ​

ElementDWF Multiple
Primary settlement3 × DWF
Biological treatment3 × DWF
Final settlement3 × DWF
Storm tanks6 × DWF

Preliminary Treatment ​

ParameterCriterion
Coarse screen spacing50-150 mm
Fine screen spacing3-6 mm
Grit channel velocity0.3 m/s
Grit chamber detention60 seconds

Primary Settlement ​

ParameterValue
Retention at DWF2-3 hours
Retention at 3×DWF0.67-1.0 hour
Surface loading at 3×DWF<1.5 m³/m²·h
Weir loading<10 m³/m·h
Tank depth3.0-4.5 m

Biological Filters ​

ParameterLow RateHigh Rate
Hydraulic loading0.1-0.4 m³/m²·h0.5-3.0 m³/m²·h
Organic loading0.08-0.15 kg/m³·d0.3-1.2 kg/m³·d
Media depth1.8-2.5 m1.2-2.0 m
RecirculationOptional0.5-4.0:1

Humus Tanks ​

ParameterCriterion
Surface loading1.2-2.0 m³/m²·h
Retention time>1.5 hours
Depth2.5-3.5 m

Activated Sludge ​

ParameterExtendedConventional
F/M ratio0.05-0.150.2-0.6
MLSS3,000-6,0001,500-3,000
HRT18-36 h4-8 h
SRT20-40 d5-15 d

Final Settlement ​

ParameterCriterion
Surface loading at DWF<0.6 m³/m²·h
Surface loading at 3×DWF<1.0 m³/m²·h
Solids loading<5 kg/m²·h
Weir loading<12 m³/m·h

US Standards ​

Ten States Standards ​

UnitKey Criteria
Primary clarifiersSOR ≤ 800 gpd/ft² at design
Aeration basinsMin 6h HRT at design
Secondary clarifiersSOR ≤ 600 gpd/ft² at design
DigestersMin 15 days HRT

WEF/ASCE Guidelines ​

Refer to:

  • WEF MOP 8: Clarifier Design
  • WEF MOP 30: Nitrogen Removal
  • WEF MOP 34: Nutrient Removal

European Standards ​

ATV-DVWK (German) ​

ParameterCriterion
Specific volume (ASP)1.5-2.0 L/PE
SVI design<150 mL/g
Peak factor (small)2.5-3.0
Peak factor (large)1.8-2.2

DIN Standards ​

StandardCoverage
DIN 4261Small treatment plants
DIN 4262Sewer construction
DIN EN 12255WWT plant standards

Discharge Standards ​

UK Urban Waste Water Directive ​

ParameterPopulationLimit
BOD₅>2,000 PE25 mg/L
COD>2,000 PE125 mg/L
TSS>2,000 PE35 mg/L
TN>10,000 PE15 mg/L
TP>10,000 PE2 mg/L

Sensitive Area Limits ​

Parameter10,000-100,000 PE>100,000 PE
TN15 mg/L10 mg/L
TP2 mg/L1 mg/L

Safety Factors ​

General Design ​

ApplicationSafety Factor
Preliminary sizing1.2-1.5
Detailed design1.1-1.25
Nitrification capacity1.5-2.0
Peak hydraulic3.0 × DWF

Equipment Selection ​

EquipmentFactor
Pumps1.1-1.2
Blowers1.1-1.15
Mixers1.15-1.25
Standby unitsN+1 minimum

Process-Specific Criteria ​

Nitrification ​

ParameterRequirement
DO>2.0 mg/L
Alkalinity>50 mg/L as CaCO₃
Temperature>10°C
pH7.0-8.5
SRT @ 10°C>12 days

Denitrification ​

ParameterRequirement
DO<0.5 mg/L
C:N ratio>4:1 (bsCOD:NO₃-N)
Temperature>5°C
Anoxic fraction20-40%

EBPR ​

ParameterRequirement
VFA:P ratio>20:1
Anaerobic HRT0.5-2.0 h
Anaerobic DO0 mg/L
Anaerobic NO₃<1 mg/L

ErgoPlanner Integration ​

Automatic Checks ​

ErgoPlanner validates designs against:

  • Selected standard (UK, US, EU)
  • Design criteria databases
  • Best practice guidelines

Warnings ​

Design warnings triggered when:

  • Loading exceeds criteria
  • Safety factors insufficient
  • Parameters outside range

Reports ​

Generate compliance reports showing:

  • Design vs criteria comparison
  • Margin calculations
  • Recommendations

References ​

  1. Sewers for Adoption 8th Edition
  2. Ten States Standards
  3. WEF Manual of Practice Series
  4. ATV-DVWK Guidelines
  5. Metcalf & Eddy "Wastewater Engineering"