COLLEGE OF ENGINEERINGSchool of Chemical, Biological, and Environmental Engineering

Novel Aerobic Sludge Membrane Reactor

(AGSM) for Sustainable Wastewater

Treatment

Zhengjian (Alex) Yang

8/26/2021

Overview

• Introduction

• Project objectives

• Preliminary results

• Future studies

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Introduction

1) Comparison with conventional activated sludge process (CAS): 75% of Footprint and 50% of energy saving

2) Enhancement of effluent water quality by integrating with membrane filtration

3) Removal of pharmaceutical and personal care products (PPCPs)-Triclosan and Ciprofloxacin

4) Recovery of valuable material from granules

-Alginate-like exopolysaccharide (ALE) as fire-resistance, curing of cement, and hydrogels (e.g., improve water retention in the soil)

-AGS based biochar as heavy metal adsorbent

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Figure 1: Operation of AGS reactor in Gleeson Hall. Figure 2: Compacted granules extracted from the AGS reactor.

Project objectives

a) Design and optimize the AGSM system with efficient removal COD and nutrients removal, flux behavior, and fouling resistance, respectively.

b) Investigating membrane fouling mechanisms by systematic membrane characterization including applying microscope (SEM), Fourier-Transform Infrared Spectroscopy (FTIR), 3-dimensional excitation emission matrix (3D-EEM), and contact angle measurement.

c) Gain a deep understanding of the mechanisms governing UF membrane filtration performance during the granulation of the flocculant sludge into mature granules.

d) Investigate the inhibition, fate, transport and removal of triclosan and ciprofloxacin in AGSM

e) Recover and harvest the granules for the ALE extraction and AGS-biochar

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COD and nutrients removal results

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Figure 3: COD removal in the AGS bioreactor. Figure 4: Ammonia removal in the AGS bioreactor.

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Figure 5: TN removal in the AGS bioreactor. Figure 6: Phosphate removal in the AGS bioreactor.

COD and nutrients removal results

Permeation results

Figure 7: Permeate flux over the period via a) UF-PES membrane on Day150, 200, and 217; b) UF-PVDF membrane on Day150, 200, and 217.

1) Nitrogen tank applied pressure of 30, 35, and 40psi on UF-PES and 20psi on UF-PVDF membrane

2) After the compaction stage (or at least 400ml DI water via the new membrane): to keep very similar final flux

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0 50 100 150 200 250 300

0

50

100

150

200

250

Day150 Flux of the new membrane Day150 AGS Effluent Day150 Flux after membrane clean

Day200 Flux of the new membrane Day200 AGS Effluent Day200 Flux after membrane clean

Day217 Flux of the new membrane Day217 AGS Effluent Day217 Flux after membrane clean

Perm

eate

flu

x(L

MH

)

Time (min)

UF-PES

TMP = 30 psi on Day150

TMP = 35 psi on Day200

TMP = 40psi on Day217

0 50 100 150 200 250 300

0

50

100

150

200

250

300

350

Day150 Flux of the new membrane Day150 AGS Effluent Day150 Flux after membrane clean

Day200 Flux of the new membrane Day200 AGS Effluent Day200 Flux after membrane clean

Day217 Flux of the new membrane Day217 AGS Effluent Day217 Flux after membrane clean

Time (min)

UF-PVDF

TMP = 20psi

Perm

eate

flu

x(L

MH

)

Permeation results

Figure 8: Normalized flux over the permeate volume of UF-PES and PVDF membrane.

J: Water flux during AGS effluent permeation J0:water flux after initial DI compaction

Lower normalized flux (Jw/J0) means more severe fouling issues.

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0 100 200 300 400

0.0

0.2

0.4

0.6

0.8

1.0

1.2 Jw/J0 PES Day217

Jw/J0 PVDF Day217

Jw/J0 PES Day200

Jw/J0 PVDF Day200

Jw

/J0

Permeate volume (ml)

Membrane resistance results

Figure 9: Membrane resistance of UF-PES and UF-PVDF on Day46, Day93, Day118, Day143, Day150,

Day200, and Day217, respectively (Note: solid pattern= PES; sparse pattern= PVDF)

Investigation on the fouling mechanisms, …• Measure s-PN, s-PS in the UF permeate to determine

the decrease of PN and PS concentrations on Day200.• Use FTIR to evaluate the functional groups on new

membrane, fouled membrane and washed membrane. That will be interesting if other functional groups than protein (amide) remaining on the membrane surface after the cleaning.

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46 93 118 143 150 200 217

0

1

2

3

4

5

6 Intrinsic Irreversible Reversible

UF-PES

UF-PVDF

Time (Day)

Mem

bra

ne r

esis

tance (

x10

13/m

)

EPS results

AGS effluent UF-PES UF-PVDF

0

20

40

60

80

100

120

140

160

180

Co

ncen

tra

tion

of

s-E

PS

(m

g/L

)

Day 200

s-PS

s-PN

UF-PES UF-PVDF

0

10

20

30

40

50

60

70

80

Reje

ction r

ate

(%

)

s-PS

s-PN

Figure 10: concentrations of s-PS and s-PN in

AGS effluent, permeation of UF-PES, and

permeation of UF-PVDF, respectively on Day

200 and Day217.

Figure 11: Rejection rate of s-PS and s-PN in UF-PES and PVDF membrane on Day200 and Day217.

10Day200

ATR-FTIR results

Figure 12: ATR-FTIR spectrums of new and cleaning UF-PES membrane on Day200. Figure 13: ATR-FTIR spectrums of new and cleaning UF-PVDF membrane on Day200.

Protein

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Fouling model results

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Fouling models under constant pressure via UF filtration• Complete blocking-cake layer: the mouths of the pores available on

the membrane surface are blocked cake formation and complete pore blockage occur simultaneously.

• Intermediate blocking-cake layer: this model explains the only blockage occurs at the pore mouth during the filtration.

• Internal membrane blocking: cake layer formation, pore constriction (e.g., deposition within the pores), and pore blocking(e.g., deposition onto the pore mouth)

Equations:

where Kb is complete blocking constant(/s), Kc is cake filtration constant (s/m2), J0 is initial flux (m/s), t is permeation time (s), V is volume filtered (m3/m2), α is the pore blockage parameter(m2/kg), and β is the pore constriction parameter (1/kg).

Fouling model results

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Figure 14: intermediate blocking- cake on UF-PES (left) and PVDF membrane (right).

Combined fouling model for constant pressure

Day 200 Day 217

PES PVDF PES PVDF

Intermediate Ki 1/m 0.007363 0.003042 0.084 0.0071

Cake Kc x10^6 s/m2 1.96 2.45 2.05 2.67

SSE 1.86E-04 0.0002402 1.20E-05 9.35E-05

R2 0.9884 0.9865 0.9993 0.9949

Table 1: key parameters of intermediate blocking- cake on UF-PES and PVDF membrane .

Fouling model results

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Figure 15: Complete blocking- cake on UF-PES (left) and PVDF membrane (right).

Combined fouling model for constant pressure

Day 200 Day 217

PES PVDF PES PVDF

Complete -cake model

Kb 1/s 1.19E-07 6.689E-08 3.27E-06 9.49E-10

Kc x10^6s/m2 1.96 2.45 2.05 2.67

SSE 1.86E-04 2.40E-04 1.18E-05 1.66E-06

R2 0.9884 0.987 0.9993 0.9999

Table 2: key parameters of complete blocking- cake on UF-PES and PVDF membrane .

Fouling model results

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Figure 16: Internal blocking on UF-PES membrane.

Day301

Parameter Unit PES

pore blocking α m2/kg 75

pore constriction β 1/kg 2793.7

Cake layer Rc/Rm 8.6

Table 3: key parameters of internal blocking on UF-PES membrane.

Future studies

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Key findings: • COD removal rate >96%, Ammonia removal rate >93%, TN

removal rate >90%, and Phosphate removal rate >99%.• The overall extent of flux lost followed the order of PVDF UF

> PES UF membrane. Flux recovery after DI water cleaning followed the reverse order.

• Irreversible membrane foulants were most likely caused by PN. From the experimental results, PVDF membrane led to more severe irreversible fouling issues than PES membrane.

Future study:• Integrate membrane filtration module external to the AGS

reactor to analyze membrane filtration performances.• Elucidate the membrane biofouling mechanisms by

characterizing both influent and membrane.• Removal efficiency and effects of PPCPs via AGSM• Recover and harvest the granules for the ALE extraction and

AGS-biochar

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ANY SUGGESTIONS?