Electrochemical Stripping to Recover Nitrogen from Source-Separated

Subscriber access provided by READING UNIV

Article

Electrochemical stripping to recover nitrogen from source-separated urine William A. Tarpeh, James M Barazesh, Tzahi Y. Cath, and Kara L. Nelson Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b05488 • Publication Date (Web): 05 Jan 2018 Downloaded from http://pubs.acs.org on January 5, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Environmental Science & Technology is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 28

Environmental Science & Technology

Electrochemical stripping to recover nitrogen from source-separated urine

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

William A. Tarpeh†,‡, James M. Barazesh†1, Tzahi Y. Cath #,‡, and Kara L. Nelson*†,‡ †

Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States ‡ Engineering Research Center for Re-inventing the Nation’s Urban Water Infrastructure (ReNUWIt), 410 O’Brien Hall, Berkeley, California 94720, United States #Department of Civil & Environmental Engineering, Colorado School of Mines, Golden, Colorado 80401, United States

Submitted to: Environmental Science & Technology October 2017 Revised: December 2017

1

Present address: Carollo Engineers., Inc. 3150 Bristol St #500, Costa Mesa, CA 92626 *Corresponding author: [email protected]

1

ACS Paragon Plus Environment


46 47

TOC

48 49 50

ABSTRACT

51

Recovering nitrogen from separately collected urine can potentially reduce costs and energy of

52

wastewater nitrogen removal and fertilizer production. Through benchtop experiments, we

53

demonstrate the recovery of nitrogen from urine as ammonium sulfate using electrochemical

54

stripping, a combination of electrodialysis and membrane stripping. Nitrogen was selectively

55

recovered with 93% efficiency in batch experiments with real urine and required 30.6 MJ kg N–1

56

in continuous-flow experiments (slightly less than conventional ammonia stripping). The effects

57

of solution chemistry on nitrogen flux, electrolytic reactions, and reactions with electro-

58

generated oxidants were evaluated using synthetic urine solutions. Fates of urine-relevant trace

59

organic contaminants, including electrochemical oxidation and reaction with electro-generated

60

chlorine, were investigated with a suite of common pharmaceuticals. Trace organics (1000 users). Pharmaceuticals were quantified by high-performance

241

liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) in the multiple reaction

242

monitoring (MRM) mode using an Agilent 1200 series HPLC system with a Hydro-RP column

243

(150 × 3 mm, 4uM; Phenomenex, Aschaffenburg, Germany) coupled to a 6460 triple quadrupole

244

tandem mass spectrometer, as described previously.31

245 246

2.5 Statistical Analysis

247

Batch nitrogen recovery efficiencies for each influent (including synthetic urine with phenol)

248

were compared using a one-way ANOVA and paired t-tests. In continuous-flow experiments,

249

nitrogen fluxes and energy demands were also compared using a one-way ANOVA and paired t-

250

tests.

10


Page 10 of 28

Page 11 of 28


251 252

3. RESULTS AND DISCUSSION

253

3.1 Nitrogen recovery from real urine in batch experiments

254

Batch experiments with real urine demonstrated that nitrogen was efficiently and selectively

255

recovered via electrochemical stripping. More than 90% (92.7 ± 4.12%) of total ammonia in real

256

urine was recovered in the trap chamber after 24 h (Figure 2). The recovery efficiency observed

257

for electrochemical stripping was similar to that reported for conventional air stripping

258

performed on hydrolyzed urine with half the total ammonia concentration (92%, 1960 mg N L–

259

1 11

260

detected in the ammonium sulfate trap solution, indicating selective ammonia recovery (Figure

261

S1); anions present in urine (e.g., acetate, phosphate) were not detected in the cathode or trap

262

chambers, showing negligible mixing between chambers. Using the same operating parameters

263

(e.g., current, recirculation rate, reactor geometry) as in batch experiments, the optimal HRT for

264

continuous electrochemical stripping appears to be between 12 and 24 hours. For comparison, a

265

previous study using electrodialysis for ammonia migration required 6 hours HRT but also an

266

additional treatment step to separate ammonia from other cations.19 For electrodialysis, increased

267

hydraulic residence time led to higher removal efficiencies but lower fluxes for ammonia,

268

particularly at high current densities (≥50 A m–2).19 For electrochemical stripping, changes to

269

HRT by changing reactor geometry or flow rate could optimize ammonia recovery efficiency

270

and flux.

). Competitor cations (e.g., Na+, K+) present in urine accumulated in the cathode but were not

271 272

3.2 Continuous electrochemical stripping with real urine

273

Continuous-flow experiments were used to further characterize electrochemical stripping in

274

terms of transmembrane fluxes, recovery efficiencies, and energy demand. With an influent 11



275

concentration of 7490 mg N L–1, average concentrations after 3-5 HRTs (3.66-6.10 hr) were

276

2960 mg N L–1 (anode), 1950 mg N L–1 (cathode), and 2250 mg N L–1 (trap). Nitrogen flux

277

across the cation exchange membrane (1710 g N m–2 d–1) was higher than the flux across the

278

hydrophobic gas permeable membrane (1010 g N m–2 d–1, Figure S2, Equations 2-3), indicating

279

that the latter is the rate-limiting step of the electrochemical stripping process and a high priority

280

for future work to reduce energy demand or increase recovery efficiency. For example, an

281

asymmetric cathode chamber could be used to create a larger membrane surface area for the gas

282

permeable membrane than the cation exchange membrane. Other gas permeable membranes

283

could also be tested to optimize ammonia flux to the trap chamber. Based on open circuit

284

experiments (no current), only 9% of flux across the cation exchange membrane was attributed

285

to diffusion; electro-migration accounted for the balance. This finding was similar to previous

286

research on electrodialysis in urine, in which diffusion accounted for 4-11% of ammonia flux

287

and the contribution of diffusion to flux was larger for longer HRTs.19 Flux across the cation

288

exchange membrane measured in this study was significantly higher than reported electrodialysis

289

values, likely due to the addition of the gas permeable membrane that increased cathodic

290

volatilization of NH3. This change reduced back-diffusion of NH3 to the anode chamber, which

291

has been documented to limit NH4+ transport from anode to cathode.21 Operation at a higher

292

current density (100 A m–2 in this study, maximum 50 A m–2 in literature, Table S5) also

293

contributed.

294 295

Overall, 61% of influent nitrogen was removed from the anode (Equation 4). Nitrogen removal

296

efficiencies (across cation exchange membrane, 60.6%, Equation 4) were higher than nitrogen

297

recovery efficiencies (across gas permeable membrane, 49.6%, Equation 5, Figure S2). Based on

12


Page 12 of 28

Page 13 of 28


298

26% of TAN remaining in the cathode at steady state, increasing cathodic HRT (currently 1.22

299

hr) could increase recovery efficiencies for both the gas permeable membrane and the overall

300

electrochemical stripping process. Longer HRTs have been demonstrated to reduce flux but

301

increase removal efficiency.19 Lower influent ammonia concentrations are expected to decrease

302

flux (Equation 2); the degree of this effect is expected to vary based on the relative contribution

303

of diffusion, which depends on a concentration gradient and varies directly with HRT.

304

Transmembrane nitrogen recovery efficiencies for electrochemical stripping were higher than

305

electrodialysis and microbial fuel cells, but lower than electrodialysis with external ammonia

306

stripping (Table S7). TAN concentration in the fertilizer product could be increased in

307

continuous flow by pumping additional urine through the anode for the same batch of sulfuric

308

acid.

309 310

Continuous-flow electrochemical stripping with real urine required 30.6 MJ kg N–1, the lowest

311

energy input reported for physicochemical electrochemical treatment of urine to date (Table S6).

312

Applying current accounted for 96% of energy required; the remaining 4% was for pumping.

313

The energy demand for electrochemical stripping was 5% less than conventional ammonia

314

stripping but still 38% higher than centralized nitrification-denitrification, which benefits from

315

economies of scale (Figure S3). Current efficiency (mol N (mol e–)–1, Equation S5) for

316

ammonium in real urine was greater than that previously reported for electrodialysis (61%)19 and

317

even surpassed 100%, indicating contributions from diffusion (Figure S4). The higher current

318

efficiency is likely due to the addition of the gas permeable membrane that enhanced transport of

319

gaseous NH3 to the trap chamber and reduced accumulation of aqueous NH3 in the cathode.

13



Page 14 of 28

320

Lower current efficiencies were observed in synthetic urine solutions due to differences in

321

electrical conductivity and competing oxidation reactions (section 3.3).

322 323

3.3 Electrochemical oxidation reactions

324

At the potentials employed for electrochemical stripping, several competing electrochemical

325

reactions could potentially take place at the anode:

326

2&' ( → (' + 4& , + 4-

E0= 1.229 V

(6)

327

2./ → ./' + 2-

E0= 1.358 V

(7)

328

&0 ..((& + 2&' ( → 2.(' + 8& , + 8-

E0= -0.29 V

(8)

329

2&0 + 2&' ( → 2(' + 7& , + 6-

E0= -0.58 V

(9)

330

Cyclic voltammetry and measurements of anticipated products were used to elucidate the

331

contributions of each potential oxidation reaction. Acetate is an organic compound abundant in

332

urine that could be oxidized (complete mineralization shown in Equation 8); ammonia could be

333

oxidized to several nitrogen species, including nitrite (Equation 9).

334 335

As expected, voltammograms performed in aqueous electrolytes confirmed that water oxidation

336

was the primary anodic reaction (Figure S5). To isolate the remaining reactions, cyclic

337

voltammetry was performed in anhydrous dimethyl sulfoxide (DMSO), an aprotic solvent.

338

Comparable voltammograms for a synthetic urine matrix containing LiCl, NaC2H3O2, and

339

(NH4)2CO3) with a single-salt solution of LiCl revealed that chloride oxidation was the second

340

most predominant reaction (Figure S6). Chloride oxidation leads to disproportionation of Cl2 to

341

hypochlorous acid (Equation 10), which was detected in the anode chamber in both synthetic and

342

real urine treated via electrochemical stripping.

14


Page 15 of 28

343


./' + &' ( → & , + ./ + &(./

(10)

344 345

Acetate and ammonia oxidation were confirmed to be insignificant based on constant anodic

346

acetate concentrations and 0.05).

396 397

Over 24 hours, both TAN and anodic pH (Figure S7) decreased, affecting the kinetics of

398

chlorination of ammonia and organics. The pH effects on speciation of HOCl/OCl–, NH3/NH4+,

399

and phenol/phenolate were included in kinetic calculations (see Section S1.2). In synthetic urine,

400

ammonia chlorination was always faster than acetate chlorination; in synthetic urine with phenol,

401

ammonia chlorination was slower than phenol chlorination for at least half of the experimental

402

period (Figure S10). Chlorination of phenol preserved ammonia for migration and led to a higher

403

nitrogen recovery in synthetic urine with phenol compared to synthetic urine alone. Thus, adding

404

phenol to synthetic urine made it a more accurate model solution for studying the

405

electrochemical treatment of real urine.

406 407

3.5 Fate of trace organic contaminants

408

Trace organic contaminants have been detected at significant concentrations in urine, especially

409

because 64% of pharmaceuticals are excreted in urine.28 Most organics in urine are hydrophilic

410

(e.g., phenolic, deprotonated amine functional groups) because lipophilic compounds tend to

411

partition into feces.36 We measured a suite of pharmaceuticals, including beta blockers,

17



412

antibiotics, and antivirals, in urine from Berkeley, California, USA; Nairobi, Kenya; and Zurich,

413

Switzerland. Compounds with notably high concentrations included sulfamethoxazole (up to 10

414

mg L–1), abacavir (up to 1 mg L–1), atenolol (up to 200 µg L–1), and carbamazepine (up to 10 µg

415

L–1; Figure 4a). Most concentrations were highest in Nairobi urine, with acetaminophen in

416

Berkeley and carbamazepine in Zurich being notable exceptions.

417 418

Four primary fates of pharmaceuticals were evaluated: reaction with electro-generated oxidants

419

in the anode chamber, electro-migration to cathode and trap chambers, transformation in the

420

cathode chamber, and transformation in the trap chamber. The latter two fates were neglected

421

based on no observed transformation in control experiments, with the exceptions of cathodic

422

transformation of emitricitabine, zidovudine, and acetaminophen (Figure S11). Based on a mass

423

balance that neglected cathodic and trap transformation, the fate of each compound in real urine

424

is presented in Figure 4b. Most importantly, pharmaceuticals were not detected in the ammonium

425

sulfate product (trap chamber). Two compounds were noticeably transported through the cation

426

exchange membrane: atenolol (4% in cathode, pKa 9.6) and metoprolol (2% in cathode, pKa 9.5).

427

Compounds containing electron-rich moieties (i.e., deprotonated amines) were removed faster in

428

the anode due to rapid reactions with electrophilic chlorine species (e.g., HOCl and

429

chloramines).37 Key exceptions included zidovudine and acyclovir, which may have back-

430

diffused from the cathode to the anode due to their hydrophilicity (log Kow 94% transformed in synthetic urine, Figure S12). For all compounds, observed first-order rate

440

constants for anodic transformation were higher in synthetic urine than in real urine (Figure S13).

441

This difference was further evidence of less chlorine quenching in synthetic urine due to the

442

presence of additional organic compounds in real urine. Higher residual concentrations of free

443

chlorine in the anode with synthetic urine could explain higher observed rate constants for trace

444

organics and lower nitrogen recovery efficiencies. While nitrogen recovery remains the primary

445

goal of electrochemical stripping, further investigations into the mechanisms contributing to

446

anodic transformation of pharmaceuticals in urine could enhance understanding of effluent

447

treatment required after electrochemical stripping.

448 449

3.6 Implications for urine treatment

450

The required energy input was calculated for each influent in continuous experiments. Real urine

451

required 30.6 MJ kg N–1, which was 55% less than ammonium sulfate, less energy than synthetic

452

urine, and 5% less than conventional ammonia stripping (Figure S2). The high conductivity of

453

real urine lowers ohmic resistance for charge transport through the anode, explaining the higher

454

energy efficiency compared to ammonium sulfate (Figure S14). Additionally, higher nitrogen

455

recovery efficiency in real urine over synthetic urine was responsible for higher energy

456

efficiency in real urine. More generally, real urine composition varies, and conductivity could be

457

an indicator for nitrogen recovery efficiency by electrochemical stripping (Figure S14).

19



458 459

In addition to nitrogen, potassium could also be recovered by electrochemical stripping.

460

Potassium was effectively recovered in the cathode chamber (Figure S1); no measurable amount

461

was detected in the anode nor in the trap after batch experiments. In most regions potassium is an

462

inexpensive fertilizer (between 0.50 and 1 USD kg–1);38,39 however, recovering it could enhance

463

the value of urine-derived fertilizers. Recovering potassium and ammonium separately, along

464

with phosphorus recovery before electrochemical stripping, could allow for production of

465

fertilizers with customized macronutrient ratios.

466 467

Urine-derived products should be safe for use, especially in the case of fertilizers. Processes for

468

nitrogen recovery benefit from selective concentration of ammonium relative to other urine

469

constituents, including other cations, pharmaceuticals, and trace elements. Besides ammonium

470

and sulfate, no other ions were observed at measurable concentrations in the ammonium

471

concentrate product (detection limits and compounds in Table S10). Similarly, pharmaceuticals

472

were not detected in the trap chamber (see section 3.5). Influent urine has already been

473

documented to contain low levels of heavy metals because most are excreted in feces.40 Trace

474

elements were not detected in the ammonium sulfate product above 30 µg L–, with two

475

exceptions: iron and zinc were detected at 400 µg L– due to impurities in sulfuric acid. Similar to

476

urine-derived fertilizers, biosolids produced from wastewater sludge are a byproduct of waste

477

treatment applied to land as fertilizer. Measured trace element concentrations were all less than

478

U.S. Environmental Protection Agency pollutant limits for land application of biosolids (Figure

479

S15a).41

480

20


Page 20 of 28

Page 21 of 28


481

The major effluent produced from electrochemical stripping is electrolyzed urine from the anode

482

chamber. Disinfectant residuals were at most 1.6 mg Cl2 equivalents L–1 for combined chlorine

483

(Figure 3b) and 0.89 mg Cl2 equivalents L–1 for free chlorine. If treated urine goes to a

484

wastewater treatment plant, the disinfectant residual will be consumed quickly when mixed with

485

sewage. If treated urine is discharged to the environment, free chlorine will likely be consumed

486

by ammonia in surface waters; however, combined chlorine at 1-2 mg L–1 could negatively

487

impact aquatic life.42 Disinfection byproducts (DBPs) were not measured in this study; future

488

work could lead to further characterization of DBPs in fertilizer and effluent produced from urine

489

by electrochemical stripping. Anode material strongly influences production of DBPs (e.g.,

490

trihalomethanes, ClO3–, and ClO4–) during electrochemical oxidation of ammonia, and is likely

491

to have similar effects during electrochemical stripping.33 Similar to free chlorine, DBPs in

492

treated urine discharged to a wastewater treatment plant will undergo further transformation; in

493

on-site electrochemical stripping systems that discharge directly to the environment, the fate of

494

DBPs is an important consideration. While DBPs may be of concern, a potential benefit of the

495

electrochemically produced chlorine is inactivation of pathogens in urine at the anode, which is

496

particularly attractive in decentralized settings that lack wastewater treatment facilities to receive

497

electrolyzed urine effluent. Trace element concentrations for all three chambers, influent urine,

498

and effluent urine from electrochemical were less than pollutant limits for land application of

499

biosolids (Figure S15a).

500 501

If catholyte is not recirculated and reused, it could also be a process effluent. Catholyte

502

concentrations of pharmaceuticals were less than 0.4 µg L–1, with the exception of atenolol (0.74

503

µg L–1) and acetaminophen (1.24 µg L–1). Trace elements were not detected above 30 µg L–1 in

21



504

catholyte, with the exception of iron (200 µg L–1) and zinc (400 µg L–1, Figure S15b-c). Further

505

optimization (e.g., of HRT, operating potential, temperature) could be investigated for

506

pharmaceuticals and element removal from effluent urine and catholyte.

507 508

In conclusion, electrochemical stripping was demonstrated at lab-scale to be an efficient process

509

for selectively recovering nitrogen from urine. Ammonium sulfate fertilizer containing

510

acceptably low levels of pharmaceuticals and trace elements was produced, and the role of

511

organics such as phenols in scavenging electro-generated chlorine was elucidated. Moving

512

toward implementation will require further characterization of the formation and fate of

513

disinfection byproducts, pathogen inactivation, and process evaluation at the pilot-scale. With

514

additional optimization, electrochemical stripping from urine could be implemented as an

515

alternative to conventional nitrogen removal from wastewater that has the potential to reduce

516

energy demand, greenhouse gas emissions, and nitrogen loads to receiving waters.

517 518

ASSOCIATED CONTENT

519

The Supporting Information (SI) contains equations for flux, energy demand, and efficiencies;

520

tables describing influent streams, membranes, and trace organic compounds; and figures

521

showing cyclic voltammetry, performance comparison of synthetic and urine solutions, and fate

522

of trace organics and elements.

523 524

AUTHOR INFORMATION

525

Corresponding author (K.L.N.):

526

Phone: 510-643-5023; e-mail: [email protected]

22


Page 22 of 28

Page 23 of 28


527 528

Notes

529

The authors declare no competing financial interests.

530 531

ACKNOWLEDGEMENTS

532

W.A.T., K.L.N., and T.Y.C. acknowledge funding provided by the National Science Foundation

533

(NSF) through the Reinventing the Nation’s Urban Water Infrastructure (ReNUWIt) Engineering

534

Research Center (http://renuwit.org; NSF Grant No. CBET-0853512). W.A.T. was also

535

supported by an NSF Graduate Research Fellowship (NSF Grant No. DGE 1106400), a Ford

536

Foundation Fellowship, and a Harvey Fellowship. Preliminary work began with a Big Ideas at

537

Berkeley Grant (2014). J.M.B. was supported by the U.S. National Institute for Environmental

538

Health Sciences (NIEHS) Superfund Research Program (Grant P42 ES004705) and the

539

Superfund Research Center at University of California, Berkeley.

23



540

References

541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584

(1) Dodds, W. K.; Bouska, W. W.; Eitzmann, J. L.; Pilger, T. J.; Pitts, K. L.; Riley, A. J.; Schloesser, J. T.; Thornbrugh, D. J. Eutrophication of U.S. Freshwaters: Analysis of Potential Economic Damages. Environ. Sci. Technol. 2009, 43 (1), 12–19. (2) The Pulse of the Bay: The State of Bay Water Quality, 2015 and 2065; SFEI Contribution #759; San Francisco Estuary Institute: Richmond, CA, 2015. (3) Kemp, W. M.; Boynton, W. R.; Adolf, J. E.; Boesch, D. F.; Boicourt, W. C.; Brush, G.; Cornwell, J. C.; Fisher, T. R.; Glibert, P. M.; Hagy, J. D.; et al. Eutrophication of Chesapeake Bay: historical trends and ecological interactions. Mar. Ecol. Prog. Ser. 2005, 303, 1–29. (4) Friedler, E.; Butler, D.; Alfiya, Y. Wastewater Composition. In Source Separation and Decentralization for Wastewater Management; IWA Publishing: London, 2013; pp 241– 257. (5) Udert, K. M.; Wächter, M. Complete nutrient recovery from source-separated urine by nitrification and distillation. Water Res. 2012, 46 (2), 453–464. (6) Etter; Tilley, E.; Khadka, R.; Udert, K. M. Low-cost struvite production using sourceseparated urine in Nepal. Water Res. 2011, 45 (2), 852–862. (7) Tarpeh, W. A.; Udert, K. M.; Nelson, K. L. Comparing Ion Exchange Adsorbents for Nitrogen Recovery from Source-Separated Urine. Environ. Sci. Technol. 2017, 51 (4), 2373–2381. (8) Ma, X. (Cissy); Xue, X.; González-Mejía, A.; Garland, J.; Cashdollar, J. Sustainable Water Systems for the City of Tomorrow—A Conceptual Framework. Sustainability 2015, 7 (9), 12071–12105. (9) Tervahauta, T.; Hoang, T.; Hernández, L.; Zeeman, G.; Buisman, C. Prospects of SourceSeparation-Based Sanitation Concepts: A Model-Based Study. Water 2013, 5 (3), 1006– 1035. (10) Wood, A.; Blackhurst, M.; Hawkins, T.; Xue, X.; Ashbolt, N.; Garland, J. Costeffectiveness of nitrogen mitigation by alternative household wastewater management technologies. J. Environ. Manage. 2015, 150, 344–354. (11) Başakçilardan-Kabakci, S.; Đpekoğlu, A. N.; Talinli, I. Recovery of Ammonia from Human Urine by Stripping and Absorption. Environ. Eng. Sci. 2007, 24 (5), 615–624. (12) Gustin, S.; Marinsek-Logar, R. Effect of pH, temperature and air flow rate on the continuous ammonia stripping of the anaerobic digestion effluent. Process Saf. Environ. Prot. 2011, 89 (1), 61–66. (13) Kabdaslı, I.; Tünay, O.; Öztürk, Đ.; Yılmaz, S.; Arıkan, O. Ammonia removal from young landfill leachate by magnesium ammonium phosphate precipitation and air stripping. Water Sci. Technol. 2000, 41 (1), 237–240. (14) Liao, P. H.; Chen, A.; Lo, K. V. Removal of nitrogen from swine manure wastewaters by ammonia stripping. Bioresour. Technol. 1995, 54 (1), 17–20. (15) Kuntke, P.; Sleutels, T. H. J. A.; Saakes, M.; Buisman, C. J. N. Hydrogen production and ammonium recovery from urine by a Microbial Electrolysis Cell. Int. J. Hydrog. Energy 2014, 39 (10), 4771–4778. (16) Feng, Y.; Yang, L.; Liu, J.; E. Logan, B. Electrochemical technologies for wastewater treatment and resource reclamation. Environ. Sci. Water Res. Technol. 2016, 2 (5), 800– 831.

24


Page 24 of 28

Page 25 of 28

585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629


(17) Zöllig, H.; Fritzsche, C.; Morgenroth, E.; Udert, K. M. Direct electrochemical oxidation of ammonia on graphite as a treatment option for stored source-separated urine. Water Res. 2015, 69, 284–294. (18) Pronk, W.; Biebow, M.; Boller, M. Treatment of source-separated urine by a combination of bipolar electrodialysis and a gas transfer membrane. Water Sci. Technol. J. Int. Assoc. Water Pollut. Res. 2006, 53 (3), 139–146. (19) Luther, A. K.; Desloover, J.; Fennell, D. E.; Rabaey, K. Electrochemically driven extraction and recovery of ammonia from human urine. Water Res. 2015, 87, 367–377. (20) Desloover, J.; Woldeyohannis, A. A.; Verstraete, W.; Boon, N.; Rabaey, K. Electrochemical resource recovery from digestate to prevent ammonia toxicity during anaerobic digestion. Environ. Sci. Technol. 2012, 46 (21), 12209–12216. (21) Dykstra, J. E.; Biesheuvel, P. M.; Bruning, H.; Ter Heijne, A. Theory of ion transport with fast acid-base equilibrations in bioelectrochemical systems. Phys. Rev. E 2014, 90 (1), 13302. (22) Rodríguez Arredondo, M.; Kuntke, P.; ter Heijne, A.; Hamelers, H. V. M.; Buisman, C. J. N. Load ratio determines the ammonia recovery and energy input of an electrochemical system. Water Res. 2017, 111, 330–337. (23) Kuntke, P.; Zamora, P.; Saakes, M.; Buisman, C. J. N.; Hamelers, H. V. M. Gaspermeable hydrophobic tubular membranes for ammonia recovery in bio-electrochemical systems. Env. Sci Water Res Technol 2016, 2 (2), 261–265. (24) Olivares-Ramírez, J. M.; Campos-Cornelio, M. L.; Uribe Godínez, J.; Borja-Arco, E.; Castellanos, R. H. Studies on the hydrogen evolution reaction on different stainless steels. Int. J. Hydrog. Energy 2007, 32 (15), 3170–3173. (25) Udert, K.; Larsen, T.; Gujer, W. Fate of major compounds in source-separated urine. Water Sci. Technol. 2006, 54 (11–12), 413–420. (26) Udert, K. M.; Larsen, T. A.; Biebow, M.; Gujer, W. Urea hydrolysis and precipitation dynamics in a urine-collecting system. Water Res. 2003, 37 (11), 2571–2582. (27) Greenberg, A. E. Standard Methods: For the Examination of Water and Wastewater, 18th Edition, 18 r.e. edition.; Amer Public Health Assn: Washington, DC, 1992. (28) Lienert, J.; Bürki, T.; Escher, B. I. Reducing micropollutants with source control: substance flow analysis of 212 pharmaceuticals in faeces and urine. Water Sci. Technol. 2007, 56 (5), 87–96. (29) Zhang, R.; Sun, P.; Boyer, T. H.; Zhao, L.; Huang, C.-H. Degradation of Pharmaceuticals and Metabolite in Synthetic Human Urine by UV, UV/H2O2, and UV/PDS. Environ. Sci. Technol. 2015, 49 (5), 3056–3066. (30) Luo, Y.; Guo, W.; Ngo, H. H.; Nghiem, L. D.; Hai, F. I.; Zhang, J.; Liang, S.; Wang, X. C. A review on the occurrence of micropollutants in the aquatic environment and their fate and removal during wastewater treatment. Sci. Total Environ. 2014, 473–474, 619–641. (31) Jasper, J. T.; Jones, Z. L.; Sharp, J. O.; Sedlak, D. L. Biotransformation of trace organic contaminants in open-water unit process treatment wetlands. Environ. Sci. Technol. 2014, 48 (9), 5136–5144. (32) Kapałka, A.; Fierro, S.; Frontistis, Z.; Katsaounis, A.; Neodo, S.; Frey, O.; de Rooij, N.; Udert, K. M.; Comninellis, C. Electrochemical oxidation of ammonia (NH4+/NH3) on thermally and electrochemically prepared IrO2 electrodes. Electrochimica Acta 2011, 56 (3), 1361–1365.

25



630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655

(33) Zöllig, H.; Remmele, A.; Fritzsche, C.; Morgenroth, E.; Udert, K. M. Formation of Chlorination Byproducts and Their Emission Pathways in Chlorine Mediated ElectroOxidation of Urine on Active and Nonactive Type Anodes. Environ. Sci. Technol. 2015, 49 (18), 11062–11069. (34) Putnam, D. F. Composition and concentrative properties of human urine. 1971. (35) Deborde, M.; von Gunten, U. Reactions of chlorine with inorganic and organic compounds during water treatment—Kinetics and mechanisms: A critical review. Water Res. 2008, 42 (1–2), 13–51. (36) Bouatra, S.; Aziat, F.; Mandal, R.; Guo, A. C.; Wilson, M. R.; Knox, C.; Bjorndahl, T. C.; Krishnamurthy, R.; Saleem, F.; Liu, P.; et al. The Human Urine Metabolome. PLOS ONE 2013, 8 (9), e73076. (37) Jasper, J. T.; Shafaat, O. S.; Hoffmann, M. R. Electrochemical Transformation of Trace Organic Contaminants in Latrine Wastewater. Environ. Sci. Technol. 2016, 50 (18), 10198–10208. (38) Source Separation and Decentralization for Wastewater Management, 1st ed.; Larsen, T. A., Udert, K. M., Lienert, J., Eds.; IWA Publishing, 2013. (39) Ott, H. Fertilizer markets and their interplay with commodity and food prices; European Commission Joint Research Centre, Institute for Prospective Technological Studies: Luxembourg, 2012. (40) Vinnerås, B. Closing the loop: recycling nutrients to agriculture. In Source Separation and Decentralization for Wastewater Management; IWA Publishing: London, 2013. (41) Lu, Q.; He, Z. L.; Stoffella, P. J. Land Application of Biosolids in the USA: A Review https://www.hindawi.com/journals/aess/2012/201462/ (accessed Aug 23, 2017). (42) Brungs, W. A. Effects of Residual Chlorine on Aquatic Life. J. Water Pollut. Control Fed. 1973, 45 (10), 2180–2193.

656

26


Page 26 of 28

Page 27 of 28

657


FIGURES

658 659

Figure 1. Schematic of the electrochemical stripping setup. For batch experiments, each

660

solution was recirculated in separate 1-L bottles. For continuous experiments the anode was fed

661

continuously and the cathode and trap were recirculated only. 6

Mass N (g)

5 Anode

4

Cathode

3

Trap

2 1 0 0

662

5

10

15

20

25

Time (hr)

663

Figure 2. Mass of total ammonia nitrogen in each chamber over time in batch experiment.

664

Dotted horizontal line is initial mass of ammonia nitrogen in anode. Error bars represent ± one

665

standard deviation. Bars not shown are smaller than symbol, except for 21 hours (n=1).

27



666 667

668 669

Figure 3. Results for varied influents from 24 hr batch experiments: (a) Nitrogen recovery

670

efficiency measured. Error bars indicate ± one standard deviation. AS= ammonium sulfate,

671

phenol = synthetic urine with phenol addition. (b) Combined chlorine measured in synthetic

672

urine, synthetic urine with phenol addition (10 mM), and real urine.

673 674

675 676 677

Figure 4. (a) Concentrations of 11 pharmaceuticals in urine from Berkeley, Nairobi, and Zurich.

678

(b) Fate of pharmaceuticals in batch experiments with real urine. Error bars represent ± one

679

standard deviation. See Table S4 for abbreviations and compound names.

28


Page 28 of 28

Electrochemical Stripping to Recover Nitrogen from Source-Separated

Recommend Documents