Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Bench-scale Arsenic Treatability Study of Municipal Wastewater to Support the New Jersey Department of Environmental
Protection’s Water Quality Standards Variance Development
March 1, 2018- May 31, 2019
Xiaoguang Meng, Jie GeStevens Institute of Technology
Project Managers: Biswarup Guha, Division of Water Monitoring and Standards; Dr. Lee Lippincott, Division of Science and Research
Project Team: Bruce Friedman, Kimberly Cenno, Jack Pflaumer, Division of Water Monitoring and Standards; Stan Cach and Anthony Pilawski, Division of Water
Quality; Chris Hoffman, Water Resource Management Municipal Finance Element; Marc Ferko, Office of Quality Assurance; Doug Haltmeier, NJ Department of Health
Inorganic Program Manager
Main ObjectiveDetermine the feasibility of using ferric chloride and alum coagulation toreduce arsenic in municipal wastewater to less than 2 µg/L.
TasksPhase 1: Chemical Characterization of Wastewater and SludgePhase 2: Coagulation Treatment of Wastewater - Jar TestsPhase 3. Filtration Removal of As in Plant A Effluent
a) Adsorptive Filtrationb) Direct Co-precipitation Filtration
Project Overview
3
Plant influent Primary clarifier effluent Plant effluent
Wastewater Treatment Plant A
Phase 1: Chemical Characterization of Wastewater
Wastewater Treatment Plant B
Alum addition for P removal
Arsenic Concentration in Plants A and B
Note: 1). analysis was performed by Stevens; detection limit=0.30 µg/L; reporting limit=1.00 µg/L.
2.432.14 2.12
2.76 2.862.282.28
7.196.99
6.51
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
1.00
10.00
100.00
PI PCE PE
pH
Con
cent
rati
on (μ
g/L
)
Arsenic Concentration in Grab Samples Collected at MCUA on 7/17/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
3.13 2.83
1.542.04
2.51
1.25
7.12 7.19
6.77
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
1.00
10.00
100.00
PI PCE PE
pH
Con
cent
rati
on (μ
g/L
)
Arsenic Concentration in Grab Samples Collected at MCUA on 5/2/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
(a)
2.66 2.742.19
2.50 2.271.941.95
6.997.18
6.36
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
1.00
10.00
100.00
PI PCE PE
pH
Con
cent
rati
on (μ
g/L
)
Arsenic Concentration in Grab Samples Collected at MCUA on 6/19/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
(b) (c)
0.49 0.410.58
0.48
7.617.46
7.57 7.51
6.00
6.50
7.00
7.50
8.00
8.50
9.00
0.10
1.00
10.00
100.00
PI PCE ICE PE
pH
Con
cent
rati
on (μ
g/L
)
Arsenic Concentration in Grab Samples Collected at HMUA on 5/15/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
(d)
1.62 1.81
1.050.80
0.35 0.38 0.35
7.787.70 7.73 7.66
6.00
6.50
7.00
7.50
8.00
8.50
9.00
0.10
1.00
10.00
100.00
PI PCE ICE PE
pH
Con
cent
rati
on (μ
g/L
)Arsenic Concentration in Grab Samples Collected at HMUA on 6/26/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
(e)
0.750.52 0.48 0.44
7.81 7.747.82
7.69
6.00
6.50
7.00
7.50
8.00
8.50
9.00
0.10
1.00
10.00
100.00
PI PCE ICE PE
pH
Con
cent
rati
on (μ
g/L
)
Arsenic Concentration in Grab Samples Collected at HMUA on 7/17/2018
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Arsenite (μg/L) pH
(f)
0.00
Plant A 6/19/2018Plant A 5/2/2018 Plant A 7/17/2018
Plant B 7/17/2018Plant B 6/19/2018Plant B 5/2/2018
Biological water treatment processes are not effective for As removal.Soluble As was removed on 6/19 possibly by alum at Plant B.
1.210.719
0.711 0.686 0.602
55.2 47.7 47.9 47.3 46.9 53.6
17.8 18.4 17.9 18.3 17.3 17.9
0.001
0.01
0.1
1
10
100
1000
Co
nce
ntr
atio
nTime
Diurnal Changes of Different Parameters at HMUA on 6/26~6/27
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Ca (mg/L) Dissolved Si (mg/L)
6/26 09:00 6/26 13:00 6/26 17:00 6/26 21:00 6/27 01:00 6/27 05:00
Grab Sample at 9:39 am on 6/26
Total Recoverable As=Non-detect
Dissolved As=Non-detect
There were no obvious diurnal changes in As, Si, and Ca.
Note: Analyses were performed by NJDOH lab.
Diurnal Changes of Arsenic, Calcium and Silicate
2.73
1.792.58 2.22 2.52
1.96
1.20 1.86 1.55 1.56 1.44 1.71
50 49.5 49.2 49.2 50.0 50.0
11.9 12.3 12.1 11.8 11.9 12.1
1
10
100
1000
Co
nce
ntr
atio
n
Time
Diurnal Changes of Different Parameters at MCUA on 6/19~6/20
Total Recoverable As (μg/L) Dissolved As (μg/L)
Dissolved Ca (mg/L) Dissolved Si (mg/L)
6/19 8:10 6/19 12:10 6/19 16:10 6/19 20:10 6/20 00:10 6/20 04:10
Grab Sample at 9:06 am on 6/19
Total Recoverable As=2.77 μg/L
Dissolved As=1.81 μg/L
Plant A, 6/19 – 6/20 Plant B, 6/26 – 6/27
3.804.00
2.50
0.10 0.21 0.160.00
1.00
2.00
3.00
4.00
5.00
6.00
5/15/2018 6/26/2018 7/24/2018
Co
nce
ntr
atio
n (
mg/
L)
PO43- -P Concentration in Wastewater Samples Collected at HMUA
Primary Clarifier Effluent Plant Effluent
1.00
1.40
1.98
0.32
1.06
1.66
0.00
1.00
2.00
3.00
4.00
5.00
6.00
5/2/2018 6/19/2018 7/17/2018
Co
nce
ntr
atio
n (
mg/
L)
PO43- -P Concentration in Wastewater Samples Collected at MCUA
Primary Clarifier Effluent Plant Effluent
(a) (b)
Removed 97% Removed
95%
Removed 94%
Removed 16%
Removed 24%
Removed 68%
Note: Analysis was performed by Stevens; detection limit=0.02 mg-P/L; reporting limit=0.10 mg-P/L
Removal of Dissolved Orthophosphate at Plants A and B
PO34- - P concentrations at Plant A PO3
4- - P concentrations at Plant B
Alum was added to wastewater before the final clarifiers to remove P at Plant B.P treatment was not required at Plant A.
Phase 2: Coagulation Treatment of Wastewater - Jar Tests
Mixing Settling
Addition of FeCl3 or alum during mixing
1 min of stirring at speed of 120 rpm
4 min of stirring at speed of 40 rpm
1 hr. of settling
Supernatant: total recoverable arsenic
Filtered Supernatant (0.45 μm): dissolved arsenic
Treated Samples on site:
1. Primary clarifier effluent
2. Mixed liquor
3. Mixed liquor supernatant
4. Plant effluent
As Removal from Primary Clarifier Effluent of Plant A
As Removal from As-spiked Effluents of Plants A and B
Arsenic Removal from Mixed Liquor and Supernatant of Plant A
8 mg/L of coagulants, initial As concentration = 7.26 µg/L.
Effect of pH on As Removal from As-spiked Effluent of Plant A
Competing Adsorption As and PO43- for Fe and Al
in As(V)- and PO43-- spiked Plant A Effluent
Initial dissolved PO43-= 0.08 mg-P/L, initial DOC=6.38 mg-C/L.
Phase 3. Filtration Removal of As in Plant A Effluenta) Adsorptive Filtration
Adsorbent media: iron oxide. a) raw effluent (PE) as column influent, EBCT=3 min, flowrate=10 ml/min; b) PE spiked with 5.0 µg/L As(V) as column influent, EBCT=3 min, flowrate=10 ml/min; c) PE as column influent, EBCT=10 min, flowrate=3 ml/min; d) PE spiked with 5.0 µg/L As(V) as column influent, EBCT=10 min, flowrate=3 ml/min.
Iron Oxide Adsorptive Filtration
Original effluent 5 ppb As spiked effluent, EBCT 3 min
Original effluent, EBCT 10 min As spiked, EBCT 10 min
Adsorbent media: adsorbent media=TiO2; plant effluent (PE) spiked with 5.0 µg/L As(V) as column influent, EBCT=10 min, flow rate=3 ml/min.
TiO2 Adsorptive Filtration Results
b) Direct Co-precipitation Filtration
Rapid sand filtration 1.6 m3/m2/h. Sand colum: ID = 5.56 cm, H = 152 cm, sand 61 cm of filter sand (mass=2.0 kg).
Plant effluent (PE) spiked with 5.0 µg/L As(V) as column influent, wastewater flow rate=65 ml/min, coagulant flowrate=1 ml/min, alum dosage= 8 mg-Al/L
Direct Co-precipitation Filtration Results
Summary
a) The total recoverable As (TAs) concentration in the influent and effluent of Plant A was in the range of 2.00-3.00 μg/L and 1.50-2.30 μg/L, respectively. The TAs in the influent and effluent of Plant B was about 0.95 and 0.57 μg/L, respectively.
b) The Biological wastewater treatment processes were not effective for As removal.
c) Ferric and alum coagulation treatment could not effectively remove As from the municipal wastewater. Very high doses of the coagulants (8 and 40 mg/L of Fe(III) or Al(III)) were required to reduce the TAs from 2.84 and 8.61 µg/L in the primary clarifier effluent and arsenate-spiked effluent samples to less than 2.00 µg/L.
d) Adsorptive filtration with iron oxide and TiO2 could only filter less than 8000 bed volumes of Plant A effluent spiked with 5 μg/L As.
e) Direct co-precipitation and rapid sand filtration with 8 ppm Al could effectively remove As from Plant A effluent spiked with 5 μg/L As.
Acknowledgment
NJDEP managers: Bruce Friedman, Kimberly Cenno, Nicholas Procopio, and Gary Brower.
HMUA: Kathleen Corcoran and her staff
Stevens Institute of Technology: Dr. Amalia Terracciano, Dr. Jinshan Wei