AOP Engineering Laboratory Application of UV/H 2 O 2 as post-treatment of WWTP secondary effluents for water reuse Renato Falcão Dantas Department of Chemical Engineering University of Barcelona COPPE, Universidade Federal do Rio de Janeiro 1 Co-autors: Bruno S Souza, Angel Cruz, Santiago Esplugas, Carmen Sans, Marcia Dezotti.

Introduction 2 AOP Engineering Laboratory Water scarcity WATER SHORTAGE Need to seek for new water sources WASTEWATER REUSE WASTEWATER REUSE Municipal effluents Lack of water sources Climate change Overconsumption Population growth

-Micropollutants contamination may cause effect on natural ecosystems and bioaccumulate; -Tertiary treatments appear as an alternative to minimize micropollutant discharge. 3 AOP Engineering Laboratory Micropollutants Introduction

-The transformation of micropollutants depends on the matrix components. 4 AOP Engineering Laboratory -Natural organic matter (NOM); -Soluble microbial products (SMPs); -Trace harmful chemicals. Micropollutants Introduction

-Atrazine ATZ was chosen as a model micropollutant. -Persistent surface and ground water contamination (μg L -1 ) -ATZ biorecalcitrant character does not favor its removal in WWTP. 5 AOP Engineering Laboratory Micropollutants Introduction

6 AOP Engineering Laboratory Reuse Introduction Spanish legislation R EAL DECRETO 1620/2007 Parameters common to all applications. Specific parameters for each application. E.Coli Turbidity Suspended solids Nematodes U SE Urban Agricultural Industrial Recreative Environmental

7 AOP Engineering Laboratory  To characterize the secondary effluent from the WWTP.  To assess UV/H 2 O 2 experimental conditions to achieve disinfection, elimination of atrazine and reuse parameters.  To monitor the population of certain microorganisms, which can be of interest for the disinfection evaluation. Objectives

8 AOP Engineering Laboratory Objectives  To study the oxidation and biodegradability of the effluent during UV/H 2 O 2 treatment.  To set up the BDOC method for analysis of biodegradability.

9 AOP Engineering Laboratory 1: Reactor 2,05 L 2: Mercury lamps Low pressure emission wavelength of 254 nm. 3: Magnetic Stirrer. 4: Aluminum coating. 5: Access for sampling. *: Cooling system (25 ° C). Experimental Reactor

-The effluent was collected from the WWTP of Gava-Viladecans (Barcelona, Spain). Capacity: 64 million liters/day. Objective to regenerate m 3 /day 10 AOP Engineering Laboratory Experimental Effluent Sampling

11 AOP Engineering Laboratory Experimental Effluent Sampling Primary Treatment Secondary Treatment Discharge Urban Wastewater Sampling Pre- filtration UV/H 2 O 2 Treatment UV/H 2 O 2 Treatment

12 AOP Engineering Laboratory Experimental Experimentation SE sample Filtration 10 µm Stored at 4 o C Spiked with 0.9 mmol L -1 of ATZ (100 µg L -1 ) H 2 O 2 Treatment Analysis

13 AOP Engineering Laboratory Table 1: Characteristics of the secondary effluent ParameterValue pH7.9 TSS (mg L -1 )63.5 VSS (mg L -1 )31.5 Turbidity (NTU)13.6 UV TOC (mg L -1 )18.2 N-NO -3 (mg L -1 )0.13 COD (mg L -1 )95.4 Redox (mV)215.4 Alkalinity (mg HCO -3 L -1 )507 Reduction with filtration 20 % 10 % 50 % Results Effluent Characterization

AOP Engineering Laboratory Results Disinfection 14 E.Coli (Escherichia Coli) CB390 (Escherichia Coli host strain).

AOP Engineering Laboratory Results Disinfection 15 SOMCPH (Somatic coliphages), DNA virus that infect E. Coli. SRC (Sulphite-Reducing Clostridia), very resitant bacterias (patogens).

16 AOP Engineering Laboratory Results ATZ removal Filtration in cartridges Sample with ATZ (2L) ATZ extraction with solvents Drying with N 2 Dissolution (2 mL) Dissolution (2 mL) ATZ concentated sample

17 AOP Engineering Laboratory Results ATZ removal Figure 1 – ATZ decay by UV/H 2 O 2 process and direct UV-C photolysis in DW and SE. 30 min Inorganic scavenging ATZ is a photolabile compound Blank experiments Efficient for ATZ removal in SE EfoM scavenging

18 AOP Engineering Laboratory  UV/H 2 O 2 can achieve UV 254 y DQO reductions around 80 % (2h).  Although UV alone could achieve similar ATZ removal, UV is less effective for SE oxidation than UV/H 2 O 2. Results Effluent Oxidation

19 AOP Engineering Laboratory Results Reuse Golf courses irrigation:  SST: 20 mg/L  Turbidity: 10 NTU  E.Coli: 200 CFU/100 mL Urban and residential reuse:  SST: 10 mg/L  Turbidity: 2 NTU  E.Coli: 0 CFU/100 mL

20 AOP Engineering Laboratory Results Biodegradability The determination of BDOC (Biodegradable Dissolved Organic Carbon) measures the change in the amount of dissolved organic carbon in a sample after the degradation process carried out by endogenous bacteria from the effluent. Ability of an effluent degraded by the effect of its own content of bacteria.

21 AOP Engineering Laboratory Results Biodegradability The treatment produces no changes on the effluent biodegradability. Raw effluent

22 AOP Engineering Laboratory  UV/H 2 O 2 Treatment with 5 ppm of H 2 O 2 can achieve the disinfection of E. coli, SRC, SOMCPH i CB390 at 5 min.  ATZ was reduced to undetectable levels in 35 minutes.  ATZ removal was importantly affected by the direct UV-C photolysis, however the application of UV/H 2 O 2 treatment under the studied conditions achieved higher oxidation of SE. Results Conclusion

23 AOP Engineering Laboratory Results Conclusion  BDOC analysis indicates that UV/H 2 O 2 treatment at the applied conditions did not changes the biodegradability of the effluent.  UV/H 2 O 2 treatment under the used conditions can achieve water quality standards for reuse after 35 minutes (golf courses irrigation), achieving after 100 minutes the quality for urban residential reuse.

24 AOP Engineering Laboratory Aknowledgements Authors are grateful to: Professor Fancisco Lucena (UB) for the microbiological analysis. Spanish Ministry of Education and Science (CTQ /PPQ; Consolider-Ingenio 2010 CSD ); The Brazilian “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” CAPES for funds received to carry out this work. NOVEDAR_Consolider

25 AOP Engineering Laboratory Thank you for the attention! Thank you for the attention Questions?

26 AOP Engineering Laboratory Additional information Pseudo first-order kinetic constant for the ATZ removal

27 AOP Engineering Laboratory Additional information

28 AOP Engineering Laboratory Additional information Theoretical energy cost of UV lamps and H 2 O 2 consumption of UV/H 2 O 2 process to treat SE

29 AOP Engineering Laboratory Additional information Total cost as a function of UV/H2O2 ratio.

30 AOP Engineering Laboratory Additional information Theoretical energy to mineralize SE by UV/H 2 O 2 process

31 AOP Engineering Laboratory Additional information ROH_UV values for different experimental conditions in SE and DW. [pCBA]0 = 240 mg L-1

32 AOP Engineering Laboratory Additional information Biodegradability (BDOC/TOC) versus treatment time at different H2O2/TOC molar ratio during UV/H2O2 process in SE. UV fluence = 8.04 mWcm-2

33 AOP Engineering Laboratory Additional information