Designing a Horizontal Subsurface Flow Constructed Wetland

Basic Design Parameters

General Description A Wastewater Types

Item Description Units

Wastewater type Industrial wastewater

Population Nos. Stormwater Runoff

Residence type

Design Flow Rate 35

Peak Factor 1.7

Max. Flow Rate 59.5

Av. Annual Temp. 18

Average Flow Rate 60.5 B Population size

0 - 5000

5001 - 10000

Influent Wastewater Characteristics 10001 - 15000

Input Output 15001 - 20000

Ammonia Nitrogen mg N/l 60 20001 - 25000

Biochemical Oxygen Demand BOD 200 25001 - 30000

Fecal Coliform F cfu/100ml 1000000

Nitrate Nitrogen mg N/l 45

Organic Nitrogen Org-N mg N/l 60

Temperature 18

Total Kjeldahl Nitrogen TKN mg N/l 60

Total Nitrogen TN mg N/l 60

Total Phosphorus P mg P/l 15

Effluent Wastewater Characteristics

Input Output

Ammonia Nitrogen mg N/l 15

Biochemical Oxygen Demand BOD 30

Fecal Coliform F cfu/100ml 10000

Nitrate Nitrogen mg N/l 20

Organic Nitrogen Org-N mg N/l 15

Temperature 18

Total Kjeldahl Nitrogen TKN mg N/l 15

Total Nitrogen TN mg N/l 15

Total Phosphorus P mg P/l 6

Domestic or Sanitary wastewater

m3

m3/dayoC

NH4+

mg O2/l

NO3-

oC oC

NH4+

mg O2/l

NO3-

oC oC

𝑄=𝐾_𝑠⋅𝐴_𝑐⋅𝑠𝐴_𝑐=𝑊⋅𝑑𝑠=Δ𝐻∕𝐿

Designing a Horizontal Subsurface Flow Constructed WetlandCalculations

Basic Design Parameters

Residence type Hydraulic Design - Darcy Formula

Residence Time

Homes Parameters Description Input Unit

Hospitals Influent Concentration Poll 200 m

Institutions Effluent Concentration Poll 30.0 m

Warehouse Temperature dependent rat 0.983

t Hydraulic Retention Time -1.930 d

Hydraulic Gradient

Wetland Input Unit Parameters Description Input Unit

Length 31 m Head differential 0.100 m

Width 12.5 m L Length 31.000 m

Depth 0.5 m s Hydraulic gradient 0.00323 m/m

Volume 193.75

Cross Sectional Area

Parameters Description Input Unit

W Width 12.500 m

d Mean water depth 0.500 m

Cross sectional area 6.250

Average Flow Rate

Parameters Description Input Unit

Hydraulic onductivity 3000 m/d

Cross sectional area 6.250

S Hydraulic gradient 0.003 m/m

Q Flow rate (max) 60.5

Commercial buildings

Ci

Co

KTV d-1

ΔH

m3

Ac m2

Ks

Ac m2

m3/d

Designing a Horizontal Subsurface Flow Constructed Wetland

First Order Model according to ReedProcess θ

BOD removal 1.104 1.06 BOD Removal NH4= removal (nitrification)

1.048

NO3- removal (dentrification)1.000 1.15 Weather:

Temp.

Influent Wastewater Characteristics Influent Concentration Pollutant

Input Effluent Concentration Pollutant

Ammonia Nitrogen mg N/l 60 Temperature dependent rate consta

Biochemical Oxygen Demand BOD 200 Hydraulic Retention Time

Fecal Coliform F cfu/100ml 1,000,000

Nitrate Nitrogen mg N/l 45 First order rate constant

Organic Nitrogen Org-N mg N/l 60 Temperature

Temperature 18 Temperature coefficient for rate con

Total Kjeldahl Nitrogen TKN mg N/l 60

Total Nitrogen TN mg N/l 60

Total Phosphorus P mg P/l 15

Effluent Wastewater Characteristics Wetland Surface Area

Input

Ammonia Nitrogen mg N/l 15 Design Flow rate

Biochemical Oxygen Demand BOD 30 Influent Concentration Pollutant

Fecal Coliform F cfu/100ml 10,000 Effluent Concentration Pollutant

Nitrate Nitrogen mg N/l 20 Temperature dependent rate consta

Organic Nitrogen Org-N mg N/l 15 Mean water depth

Temperature 18 Wetland porosity (decimal fraction)

Total Kjeldahl Nitrogen TKN mg N/l 15 Wetland surface area

Total Nitrogen TN mg N/l 15

Total Phosphorus P mg P/l 6

k20

KNHDesign Date:

NH4+

mg O2/l

NO3-

oC oC

Fraction of HSSF bed depth occupied by root zone (decimal fraction, 0 to 1)Nitrification rate constant at 20oC

NH4+

mg O2/l

NO3-

oC oC

Designing a Horizontal Subsurface Flow Constructed WetlandFirst Order Model according to Reed et al. 1995

BOD Removal Ammonia Nitrogen Removal

LAB.:

Test #: Weather:

Temp.

Parameter Input Units

Influent Concentration Pollutant 200 mg/l Influent Concentration Pollutant

Effluent Concentration Pollutant 30 mg/l Effluent Concentration Pollutant

Temperature dependent rate consta 0.983 Temperature dependent rate constant

Hydraulic Retention Time t -1.92993 d Hydraulic Retention Time

Parameter Input Units

First order rate constant 1.104 1/d First order rate constant

T 18 Temperature

Temperature coefficient for rate con θ 1.06 Temperature coefficient for rate const

0.983

rz

0.01854 1/d

Wetland Surface Area Wetland Surface Area

Parameter Input Units

Q 35 Design Flow rate

Influent Concentration Pollutant 200 mg/l Influent Concentration Pollutant

Effluent Concentration Pollutant 30 mg/l Effluent Concentration Pollutant

Temperature dependent rate consta 0.983 1/d Temperature dependent rate constant

d 0.5 m Mean water depth

Wetland porosity (decimal fraction) n 0.35 Wetland porosity (decimal fraction)

Wetland surface area A 385.986 Wetland surface area

Design Date:

Sampled By:

Ci

Co

KTV

K20

oC

KT

Fraction of HSSF bed depth occupied by root zone (decimal fraction, 0 to 1)

Fraction of HSSF bed depth occupied by root zone (decimal fraction, 0 to 1)

Nitrification rate constant at 20oC KNH Nitrification rate constant at 20oC

m3/d

Ci

Co

KTV

m2

𝐴=[𝑄(ln〖𝐶 _𝑖 〗− ln〖𝐶 _𝑜 〗 )]∕[𝐾_𝑇𝑉⋅𝑑⋅𝑛]

𝐶_𝑜/𝐶_𝑖=𝑒^(−𝐾_𝑇𝑉⋅𝑡)

𝐾_𝑇=𝐾_20⋅𝜃^((𝑇−20))

𝐾_𝑁𝐻=0.01854+0.3922(〖 〗𝑟𝑧 ^2.6077)

Ammonia Nitrogen Removal

LAB.:

Test #:

Parameter Input Units

Influent Concentration Pollutant 60 mg/l

Effluent Concentration Pollutant 15 mg/l

Temperature dependent rate constant 0.983

Hydraulic Retention Time t -1.41027 d

Parameter Input Units

First order rate constant 0.41074 1/d

Temperature T 18

Temperature coefficient for rate const θ 1.048

0.374

Parameter Input Units

rz 1

0.41074 1/d

Wetland Surface Area

Parameter Input Units

Design Flow rate Q 35

Influent Concentration Pollutant 60 mg/l

Effluent Concentration Pollutant 15 mg/l

Temperature dependent rate constant 0.983 1/d

Mean water depth d 0.5 m

Wetland porosity (decimal fraction) n 0.35

Wetland surface area A 282.054

Sampled By:

Ci

Co

KTV

K20

oC

KT *K20 = KNH

Fraction of HSSF bed depth occupied by root zone (decimal fraction, 0 to 1)Nitrification rate constant at 20oC KNH

m3/d

Ci

Co

KTV

m2

𝐴=[𝑄(ln〖𝐶 _𝑖 〗− ln〖𝐶 _𝑜 〗 )]∕[𝐾_𝑇𝑉⋅𝑑⋅𝑛]

𝐶_𝑜/𝐶_𝑖=𝑒^(−𝐾_𝑇𝑉⋅𝑡)

𝐾_𝑇=𝐾_20⋅𝜃^((𝑇−20))

𝐾_𝑁𝐻=0.01854+0.3922(〖 〗𝑟𝑧 ^2.6077)