The document discusses the optimization of enhanced biological phosphorus removal (EBPR) through anaerobic, aerobic, and anoxic processes, focusing on a study conducted at the Beirolas wastewater treatment plant. Key objectives included replicating the EBPR process in a lab setting, assessing microbial composition, and analyzing phosphorus removal efficiency, with results indicating up to 92% phosphorus removal under specific conditions. The findings suggest that the presence of different types of phosphorus-accumulating organisms (PAOs) plays a significant role in the efficiency of phosphorus removal processes.

1. U niversità degli Studi di Salerno Dipartimento di Ingegneria Civile Laurea in Ingegneria per l’Ambiente ed il Territorio in Impianti di trattamento delle acque reflue II ENHANCED BIOLOGICAL PHOSPHORUS REMOVAL BY ANAEROBIC, AEROBIC/ANOXIC PROCESSES Allievo Paolo Siano N.Mat. 06205-000160 Relatore: Prof.Ing. Luigi Rizzo Correlatore: Prof.ssa. Maria Ascensão Reis

2. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : 29 April 2011 Framework Background Objectives Materials and methods Wastewater sampling Batch test Chemical Analysis Results Phosphorus in Beirolas WWTP Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Conclusions

3. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : 29 April 2011 Background

4. Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : 29 April 2011 World Resource i nstitute (www.wri.org)

5. Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : 29 April 2011 World Resource i nstitute (www.wri.org)

6. Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : 29 April 2011 World Resource i nstitute (www.wri.org) Parameter Power plant in terms of population equivalent D.E. 91/271/CEE 10,000 – 100,000 >100,000 Concentrazione % di riduzione Concentr. % di riduz. Total P (P mg/l) ≤ 2 80 ≤ 1 80 Total N (N mg/l) ≤ 15 70-80 ≤ 10 70-80

7. PRECIPITATION ADDITION OF METAL SALTS ENHANCE Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 ANAEROBIC/AEROBIC PROCESSES promoted by P oliphosphate A ccumulating O rganisms (PAOs) Much lower operating costs Reduced sludge production Reuse processed sludge Chemical Removal Biological Removal (EBPR)

8. Phoredox [A/O] ANAEROBIC CONDITIONS AEROBIC CONDITIONS Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 energy liquid phase energy O 2 liquid phase O 2

9. Phoredox 3-stage [A 2 /O] Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 energy O 2 liquid phase N O 2 N O 3

10. University of Cape Town (UCT) Bardenpho Combined nitrogen and phosphorus removal schemes Virginia Initiative Plant [VIP] A 2 /O Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011

11. Background : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Carvalho et. al. (2007) observed difference in anoxic P-uptake and proposed hypothesis that different Accumulibacter clades have different metabolic capabilities . *** Flowers et al., (2009) confirmed that two different clades have affinities to nitrate: type I Accumulibacter, hereafter refered as PAOI , seems having the ability to denitrify using nitrate, contrary to Type II Accumulibacter, hereafter PAOII . Although anoxic conditions with nitrate seems to favor PAOI over PAOII, they seem be able to co-exist.

12. The aim of the study has been the optimization of the Enhanced Biological Phosphorus Removal (EBPR) through: Objectives Reproduction of the EBPR process at lab-scale and evaluation process efficiency; Estimation of the microbial composition of Beirolas UWWTP through chemical analysis, according to the method proposed by Meinhold et al. (1999). : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011

13. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Experimental

14. Materials and methods: wastewater sampling Activated sludge was collected from Beirolas UWWTP (Loures, Portugal) : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Beirolas UWWTP

15. Materials and methods: wastewater sampling "Barden-pho" BPR unit configuration based on 3-stages : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Anaerobic zone (4.3% of total); Anoxic zone ( 21.3% of total); Aerobic zone (74.4% volume total).

16. Materials and methods: wastewater sampling : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 5 L of sludge from aerobic tank to arrange biological batch tests.

17. Materials and methods: wastewater sampling : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Additional samples from : biological units (Anaerobic, anoxic and aerobic tank); primary and secondary settling. In order to characterize the plant.

18. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Materials and methods: batch test Batch test conditions Acetate as carbon source Temperature of 22°C ( ± 2°C) pH in the range 6.5 ÷ 7.5 SPLIT ANAEROBIC REACTOR AEROBIC REACTOR ANOXIC REACTOR Volume 1.5 L Volume 0.6 L Volume 0.6 L

19. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Chemical Analysis Phosphorus, Acetate, Nitrate Hight Pressure Liquid Chromatography (HPLC) IonPac® AS9-HC Phosporus Ascorbic acid method Skalar 5100 Ammonia Ammonia gas sensing combination electrode Thermo Orion, NH4/95-12 Total and Volatile Suspended Solids (TSS, VSS) Membrane Filtration Method

20. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 ANAEROBIC REACTOR Time (min) Conc. of P ~ 120 ~ 360 Max release of P anaer. aer./anox. Carbon comsuption Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests

21. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 AEROBIC REACTOR Max release of P Max aerobic uptake of P Time (min) Conc. of P anaer. ~ 120 ~ 360 aer./anox. Carbon comsuption Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests

22. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 ANOXIC REACTOR Max release of P Max anoxic uptake of P Time (min) Conc. of P ~ 120 ~ 360 anaer. aer./anox. Carbon comsuption Nitrate comsuption Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests

23. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Batch test for B 4 samples. Initial Acetate concentration 25 ppm; Initial concentration of P 20ppm; Initial NO 3 25ppm. Anaerobic condition Aerobic/Anoxic condition

24. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Batch test for B 6 samples. Initial Acetate concentration 30 ppm; Initial concentration of P 20ppm; Initial NO 3 25ppm. Anaerobic condition Aerobic/Anoxic condition

25. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Batch test for B 7 samples. Initial Acetate concentration 40 ppm; Initial concentration of P 20ppm; Initial NO 3 25ppm. Spiking of P Anaerobic condition Aerobic/Anoxic condition Aerobic condition

26. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Batch test for B 8 samples. Initial Acetate concentration 40 ppm; Initial concentration of P 20ppm; Initial NO 3 25ppm. Anaerobic condition Aerobic/Anoxic condition P Ae (on Ax)

27. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Batch test for B 5 samples. Initial Acetate concentration 50 ppm; Initial concentration of P 20ppm; Initial NO 3 25ppm. Anaerobic condition Anoxic condition Aerobic condition

28. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Anaerobic-Aerobic and Anaerobic/Anoxic batch tests Summary of the anaerobic-aerobic-anoxic activity batch tests results carried out According to other studies n° Batch Initial Hac P-release rate An. P/HAc ratio Ae P-uptake rate Ax. P-uptake rate Ax/Ae P uptake rate [-] [mg/L] [mgP/gVSS/h] [molP/molHAc] [mgP/gVSS/h] [mgP/gVSS/h] [%] B 4 25 9.73 0.37 7.40 3.68 36.45 B 6 30 11.63 0.19 3.87 1.50 28.44 B 7 40 6.68 0.18 8.57 3.55 45.34 B 8 40 9.98 0.22 6.51 1.88 49.40 B 5 50 8.61 0.22 n.r. n.r. n.r. avarage >> 9.33 0.23 6.59 2.65 39.91 stand.dev. >> 1.83 0.08 2.00 1.12 9.36

29. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Assessing PAO/DPAO activity Time (min) Conc. of P ~ 120 ~ 360 anaer. aer./anox. Anoxic uptake Aerobic uptake Anaerobic release Aerobic uptake Anoxic uptake Acetate consuption Nitrate consuption XDPAO XPAO D Pax D Pox = Relative activity of DPAO in EBPR systems (Meinhold et al.,1999)

30. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: Assessing PAO/DPAO activity XDPAO XPAO D Pax D Pox = Relative activity of DPAO in EBPR systems (Meinhold et al.,1999)

31. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: phosphorus in Beirolas WWTP Efficiency 92% ? “ secondary” P-release

32. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Results: WWTP & Batch tests

33. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Conclusions EBPR process at lab-scale was reproduced and typical trends of phosphorus, nitrate and acetate were observed; The batch tests results obtained suggest that phosphorus removal is due to two type of PAOs: PAOs type I (also called DPAOs) that are likely to be able to reduce nitrate and PAO type II that cannot; Relative chemical activity of PAOs and DPAOs was estimated, (Meinhold et al. 1999): DPAOs occurrence as high as 40% and PAOs occurrence as high as 60%; Phosphorus removal efficiency at Beirolas UWWTP is quite variable, but under the investigated conditions a 92% removal was observed; The higher the concentration of intracellular phosphorous in aerobic tank of UWWTP the higher the phosphorus release rate in the anaerobic phase of batch test.

34. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011 Conclusions The knowledge of the microbial composition and its efficiency is key factor to perform good P and N removals.

35. : : Enhanced Biological Phosphorus Removal by anaerobic, aerobic/anoxic processes : : Presented on the 29 April 2011