1
Supporting information
525
Phosphate recovery from human wast
e via the formation of
526
hydroxyapatite during electrochemical wastewater treatment
527
528
529
Cl
é
ment
A.
Cid
†
, Justin T. Jasper
†
, Michael R. Hoffma
nn
*
530
531
Linde
-
Robinson Laboratories
532
California Institute of Technology
533
1200 East California Boulevard
534
Pasadena CA,
91125
535
536
†
These authors contributed equally to this work
537
*
C
orresponding
author:
mrh@caltech.edu
538
539
Number of pages:
1
3
(including t
his
cover page)
540
Number of figures:
9
541
Number of tables:
1
542
2
Supplementary figures
543
3
544
Figure S
1
:
D
ried
stainless steel cathode after more than 800 h
of toilet wastewater
545
electrolysis.
Most of the precipitate from the bottom of the electrode had fallen off
546
during
transport
ing
and dism
a
nte
l
ling
the electrode array.
547
548
4
549
Figure S
2
:
[Ca
2+
]
0
, [Mg
2+
]
0
, [PO
4
3
-
]
T,0
,
[
HCO
3
-
]
0
, and current density
j
(log10 scale)
for
550
each set of triplicate experiments reported in Table S1.
551
5
552
Figure S
3
: Ammonia (NH
4
+
+ NH
3
),
Mg
2+
, Ca
2+
, total PO
4
3
-
, NO
3
-
, and free chlorine (HOCl
553
+ ClO
-
)
concentrations during
electrochemical treatment (3.3 V; 50 A) of toilet
554
wastewater ([Cl
-
]=80 mM) in pilot
-
scale reactor.
555
556
6
557
Figure S
4
:
Thermogravimetric analysis of the precipitate collected from the
558
electrochemical
reactor (thin line) compared to
calcium carbonate (thick line).
559
560
7
561
562
Figure S
5
:
SEM/EDS mapping of precipitate collected from stainless steel cathodes
563
after several cycles of toilet wastewater electrolysis.
564