Nutrient recovery from municipal wastewater

using ED/EDIRubaba Mohammadi

1

• Optimization of nutrient recovery from different source point of wastewater treatment plant

• Compare the products

• Compare the energy consumption

• Cost

ED and EDI

Objectives:

Effect of volume and flow rate:

Operating time: 20 minutes, voltage:6.6 v

2/2 2/1 2/0.5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

Rec

ov

ery

rat

e (C

/C0)

Volume ratio (VD / VC)

Nitrate recovery rate

TDS recovery rate

EC recovery rate

Salinity recovery rate

a(C150)

0 5 10 15 20 25 30

1,0

1,2

1,4

1,6

1,8

2,0

2,2

Nit

rate

rec

ov

ery

rat

e(C

/C0)

Time (min)

40Lh-1 flow

60Lh-1 flow

80Lh-1 flow

a(C150)

Effect of cell pairs:

The recovery rate of nitrate as a function of the cell pairs in

150 and 500 mgL-1 NO3- concentration (flow rate 60 Lh-1,

operation time 30 min, VD/VC 2/0.5).

Nutrient recovery in present of other ions from MBR effluent:

0 5 10 15 20 25

0

10

20

30

40

50

60 current1

current2

resistance 1

resistance

Voltage (volts/cell-pair)

Curr

ent (m

A/c

ell-

pair)

0.35

0.40

0.45

0.50

0.55

0.60

Resis

tance (W

/cell-

pair)

Limiting current density of multi anions solution and

MBR permeate

Effect of different electrolyte type on ED efficiency (secondary

setteling clarifier):

0 10 20 30 40

1.5

2.0

2.5

3.0

3.5

4.0N

itra

te r

ecovery

rate

(C/C

0)

Time (Min)

Na2SO4

NaNO3

H2SO4

NaCl

Nutrient recovery in present of other ions (secondary setteling

clarifier and MBR):

0 20 40 60 80 100 120

0

2

4

6

8

10

Ion

s re

cov

ery

rat

e

Time (Min)

Cl-1

NO3 -1

Na+1

SO4-2

Ca+2

K+1

0 20 40 60 80 100 120

0

2

4

6

8

10

Cl-

NO3-

SO4-2

Ion r

ecover

rate

Time(min)

Two stage batch ED on nitrate efficiency (secondary setteling

clarifier):

0 20 40 60 80 100 120 140 160 180

-12

-8

-4

0

4

8

12

16

20

Nit

rate

co

nce

ntr

atio

n r

ate(

C/C

0)

Time (min)

First stage concentrate

Second stage concentrate

First stage dilute

Second stage dilue

(a)

Effect of multi-stage batch ED on

NO3-1 recovery and removal rate

minus rate numbers represent the

removal rate

Process design of the two-stages-

batch ED system.

Standards for potable water,

and chemical analysis of

potable water of Mikkeli

city, feed wastewater, ED

diluted and concentrated

product

Parameter Table World

Health

Organiza

tion

European

Union

Potable

water

Diluted

product

wastewater Concentr

ated

product

Concentr

ated

product(s

tage2)

Aluminum Al 0,2 mg L-1 0.03 0 0.02 0.03 0.05

Cadmium Cd 3 μg L-1 5 μg L-1 0 0 0 0

Calcium Ca mg L-1 56.92 0 52.4 214.48 850

Chromium Cr 50μg L-1 50 μg L-1 0 0 0 0 0

Copper Cu “ 2.0 mg L-1 0.26 0 0.02 0.03 0.07

Iron Fe 0,2 mg L-1 0.03 0.03 0.12 0.06 0.08

Lead Pb “ 10 μg L-1 0 0.07 0.12 2.69 40

Magnesium Mg 6.51 3.8 1.8 11 31

Nickel Ni “ 20 μg L-1 0 0.01 0.01 0.01 0.02

Nitrate NO3-1 50 mg L-1 50 mg L-1 5.9 10 100.8 460 2002

Total

dissolved

solid

TDS 168 87.8 503 1740 8019

Electric

conductivity

EC 2500 µS cm-

1 at 20 °C

234 124 706 2450 8502

Salinity Sa mg L-1 113 59.4 340 1260 4669

pH 7 7.6 7 7.63 7.5

Phosphorus P 0 0.16 0.27 5.4 22

Total organic

carbon

TOC 3.71 6.32 10.19 16.32 25

Potassium K 15.2 1 33.55 127.3 381

Sulfate SO4-2 40.9 18.7 113.3 477.3 1908

Sodium Na 23 9.1 68.2 659.6 3000

Zinc Zn 0 0 0 0 0

chlorides Cl 250 mg L-1 25.4 6.8 67.8 332.7 1200

Total energy

consumption:1.24 kWh

kg-1 NO3-1 ,2 L recovered

water per 0.5 L

concentrated solution

Fouling:TOC analysis : The TOC content decreased from 10.19 ±1.2 mg L-1 to the average 6.32 ±0.5mg L-1 in the diluted stream in 120 min, respectively; while it increased to average of

16.32 ±1.5 and 25 mg L-1 in concentrated solution after ED treatment in 2 cycles 120 min,

respectively.

Surface image of membrane(a,b):fresh surface of

CEM ,(a1, ,b1):used surface of CEM,(c,d):fresh

surface of AEM,( c1, ,d1):used surface of AEM

Total cost

Capital cost

Operational cost

Total cost:

40%30% 33%

32%

30%33%

25%

39%33%

2% 2% 3%

100 200 300

0

20

40

60

80

100

Capital cost contr

ibution (

$)

Product water concentration (mgL-1)

spacer

pump

membrane

electrode

18% 17% 18%

82% 83% 82%

100 200 300

0

20

40

60

80

100

Ene

rgy c

onsum

ptio

n(K

JL

-1)

Product water concentration (mgL-1)

pump

desalination

Operational and capital cost: