aop engineering laboratory application of uv/h 2 o 2 as post-treatment of wwtp secondary effluents...

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Application of UV/H2O2 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

1Co-autors: Bruno S Souza, Angel Cruz, Santiago Esplugas, Carmen Sans, Marcia Dezotti.

IntroductionIntroduction

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tory Water scarcity

WATER SHORTAGE

WATER SHORTAGE Need to seek for new

water sources

Need to seek for new

water sources

WASTEWATERREUSE

WASTEWATERREUSE Municipal effluentsMunicipal 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.

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tory Micropollutants


-The transformation of micropollutants depends on the matrix components.

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-Natural organicmatter (NOM);

-Soluble microbial products (SMPs);

-Trace harmful chemicals.

Micropollutants


-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

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tory Micropollutants


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tory Reuse


Spanish legislation RREAL DECRETO EAL DECRETO

1620/20071620/2007RREAL DECRETO EAL DECRETO

1620/20071620/2007

Parameters common to all applications.

Specific parameters for each application.

•E.Coli

•Turbidity

•Suspended solids

•Nematodes

USEUSE

•Urban

•Agricultural

•Industrial

•Recreative

•Environmental

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To characterize the secondary effluent

from the WWTP.

To assess UV/H2O2 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 .

ObjectivesObjectives

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ObjectivesObjectives

To study the oxidation and

biodegradability of the effluent during

UV/H2O2 treatment .

To set up the BDOC method for analysis of biodegradability.

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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).

ExperimentalExperimentalReactor

-The effluent was collected from the WWTP of Gava-Viladecans (Barcelona, Spain).

Capacity: 64 million liters/day.

Objective to regenerate 32.000 m3/day 10

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ExperimentalExperimentalEffluent Sampling

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ExperimentalExperimentalEffluent Sampling

Primary Treatment

Primary Treatment

Secondary TreatmentSecondary Treatment

Discharge

Urban Wastewater

Sampling

Pre-filtration

Pre-filtration

UV/H2O2

Treatment

UV/H2O2

Treatment

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ExperimentalExperimentalExperimentation

SE sample

Filtration 10 µm

Stored at 4 oC

Spiked with 0.9 mmol L-1 of ATZ (100 µg L-1)

H2O2 Treatment Analysis

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Table 1: Characteristics of the secondary effluent

Parameter Value

pH 7.9

TSS (mg L-1) 63.5

VSS (mg L-1) 31.5

Turbidity (NTU) 13.6UV254 0.512

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-3L-1) 507

Reduction with

filtration

20 %

10 %

50 %

ResultsResultsEffluent Characterization

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ResultsResultsDisinfection

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E.Coli (Escherichia Coli)

CB390 (Escherichia Coli host

strain).

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ResultsResultsDisinfection

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SOMCPH (Somatic coliphages), DNA virus that infect E. Coli.

SRC (Sulphite-Reducing Clostridia), very resitant bacterias (patogens).

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ResultsResultsATZ removal

Filtration in cartridges

Filtration in cartridges

Sample with ATZ

(2L)

ATZ extraction

with solvents

ATZ extraction

with solvents

Drying with N2

Drying with N2

Dissolution(2 mL)

Dissolution(2 mL)

ATZ concentated

sample

100 µg L-1 = Solid Extraction

100 µg L-1 = Solid Extraction

0

20

40

60

80

100

0 4000 8000 12000 16000

[ATZ

](µg

L-1)

UV dose (mJ cm-2)

SE - UV/H2O2

SE - UV/H2O2 Low alkalinity

DW - UV/H2O2

DW - UV

SE - UV

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ResultsResultsATZ removal

Figure 1 – ATZ decay by UV/H2O2 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

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UV/H2O2 can achieve UV254 y DQO reductions around 80 % (2h).

Although UV alone could achieve similar ATZ removal, UV is

less effective for SE oxidation than UV/H2O2.

ResultsResultsEffluent Oxidation

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ResultsResultsReuse

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

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ResultsResultsBiodegradability

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.

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ResultsResultsBiodegradability

The treatment produces no changes on the effluent

biodegradability.

The treatment produces no changes on the effluent

biodegradability.

Raw effluent

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UV/H2O2 Treatment with 5 ppm of H2O2 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/H2O2 treatment under the

studied conditions achieved higher oxidation of SE.

ResultsResultsConclusion

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ResultsResultsConclusion

BDOC analysis indicates that UV/H2O2 treatment at the applied

conditions did not changes the biodegradability of the effluent.

UV/H2O2 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.

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AknowledgementsAuthors are grateful to:

Professor Fancisco Lucena (UB) for the microbiological analysis.

Spanish Ministry of Education and Science (CTQ2008-1710/PPQ; Consolider-Ingenio 2010 CSD2007-00055);

The Brazilian “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” CAPES for funds received to carry out this work.

NOVEDAR_Consolider

http://www.brandsoftheworld.com/download/brand/183384.html

http://www.educacion.es/portada.html

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Thank you for the attention!

Thank you for the

attention

Questions?

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tory Additional information

Method Matrix k (min-1)

UV/H2O2 DW 2.0706 SE 0.1359

SE low alkalinity 0.1610 UV

DW 0.3633 SE 0.1142

1

Pseudo first-order kinetic constant for the ATZ removal

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1

(C2)

CDIT (m/z=230)

DEA (m/z=188)

DEIA (m/z=146)

(C1)

(C1*)

(B1)

DEHA (m/z=170)

(A1)

DIA (m/z=174)

DEIA (m/z=146)

(A2)

OAAT (m/z=128)

(B3)

ODIT (m/z=212)

ATZ (m/z=216)

HA (m/z=198)

(B2)(B2*)

DIHA (m/z=156)

HA (m/z=212)

(D1) (D2)

ATZ (m/z=216)

Direct UV photolysis pathway

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Period Reaction Time (h)

UV expensed (kWh m-

3)

UV Cost (€ m-3)

H2O2 consumption

(kg m-3)

H2O2 cost

(€ m-3)

Total costs

(€ m-3)

Disinfection 0.067 0.068 0.008 6.17x10-4 0.003 0.011 ATZ

elimination 0.580 0.592 0.070 2.55x10-3 0.013 0.083

Complete reaction

2.000 2.040 0.240 5.0x10-3 0.025 0.265

1

Theoretical energy cost of UV lamps and H2O2 consumption of UV/H2O2 process to treat SE

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Molar ratio H2O2 cost (€ m-3) Total cost (H2O2 cost

+ 2h UV lamps cost) (€ m-3)

H2O2/TOC = 1 0.20 0.44 H2O2/TOC = 2 0.40 0.64 H2O2/TOC = 3 0.60 0.84 H2O2/TOC = 4 0.80 1.04

1

Total cost as a function of UV/H2O2 ratio.

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Conditions kWh per g C-1 € per g of eliminated C

[H2O2]o=5.1 mg L-1 2.925 0.344

H2O2/TOC = 1 1.463 0.172 H2O2/TOC = 2 1.164 0.137 H2O2/TOC = 3 0.925 0.109 H2O2/TOC = 4 0.875 0.103

1

Theoretical energy to mineralize SE by UV/H2O2 process

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0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

H2O2/ATZ = 2.8 10-3 H2O2/TOC = 1 H2O2/TOC = 2 H2O2/TOC = 3 H2O2/TOC = 4

RO

H_U

V (

10-1

4 M s

L J

-1)

SE

DW

H2O2 /ATZ = 2.8 10-3 H2O2 / TOC = 1 H2O2 / TOC = 2 H2O2 / TOC = 3 H2O2 / TOC = 4

ROH_UV values for different experimental conditions in SE and DW. [pCBA]0 = 240 mg L-1

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0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

30 m

in

60m

in

90 m

in

120

min

30 m

in

60 m

in

90 m

in

120

min

30 m

in

60m

in

90 m

in

120

min

30 m

in

60m

in

90 m

in

120

min

H2O2/TOC = 1 H2O2/TOC = 2 H2O2/TOC = 3 H2O2/TOC = 4

BD

OC

/ T

OC

H2O2/TOC = 1 H2O2/TOC = 2 H2O2/TOC = 3 H2O2/TOC = 4

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

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aop engineering laboratory application of uv/h 2 o 2 as post-treatment of wwtp secondary effluents...

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