Pilot scale study of pharmaceutical wastewatertreatment with Electro-Phenton Technology

Ana Marilia da Trindade Baratamariliabarata@tecnico.ulisboa.pt

Instituto Superior Tecnico, Lisboa, Portugal

June 2017

Abstract

This work was developed in a pharmaceutical industry, simulating an industrial Wastewater TreatmentPlant (WWTP) in a pilot plant testing in situ pharmaceutical wastewater. Project drivers were theinstallation of a new top-of-the-range WWTP on site that was reliable for API degradation and fullcompliance to the environmental license. Treatment setup varied along the project to better assess thebest configuration and operational parameters for future operation.The future WWTP primary degradation stage should be based on Electro-Peroxi-Coagulation technology(EPC), an Advanced Oxidation Process (AOP) included in the Best Available Techniques (BATs) forpharmaceutical wastewater treatment. EPC technology promotes the chemical degradation of doublebounded and branched chain organics through oxidation with the addition of hydrogen peroxide and ferricions dosed by iron electrodes at an electrochemical reactor. EPC Reactor performance was assessedwith focus on some critical parameters (Chlorides, Adsorbable Organic Halides (AOX), Dichloromethane(DCM), Chemical Oxygen Demand (COD) and Metals) as well as on wastewater biodegradability andAPI degradation.In a total of 80 trial tests, the EPC reactor degraded 72.33 % of the initial organic matter with 70 to90% of the overall degradation occurring in the first 30minutes of reaction. Environmental parameterassessment concluded that the EPC technology treats efficiently the pharmaceutical wastewater (withcompound degradation from 50 to 60% removal of chlorides and ammonia and 80 to 99% removalof the remaining profiled compounds). Wastewater toxicity and respiratory inhibition to the aquaticenvironmental decreased 95% and biodegradability increased in 89%. API degradation was for all theprofiled API above 90%.Overall, this project validated the EPC technology as suited to be installed in the pharmaceutical siteas a reliable and robust treatment. Future WWTP will also include a biologic reactor downstream theEPC reactor to upgrade de treatment performance. Economic analysis concluded that this high valueinvestment will have a payback bellow three years for an WWTP suited to a site expansion that shoulddouble present capacity and wastewater complexity.

Keywords: Electro-Peroxi-Coagulation, Advanced Oxidation, Pharmaceutical Wastewater, HydrogenPeroxide, Active Pharmaceutical Ingredient

1. Scope and Objectives

1.1. Pharmaceutical Wastewater

Water contaminants not treated or not containedcan impact the water courses (on surface andunderground waters) and contaminate the soilsaffecting living creatures and endangering thesupply of safe water as a human resource. Atthe present day, API are considered as emergingcontaminants. Emerging contaminants are definedas compounds that are still unregulated or inprocess of regulation and that can be a threat toenvironmental ecosystems and human health.Despite the absence of regulatory limits for the API

content in pharmaceutical wastewater enteringthe hydric environment and the sewers, predictednon effect concentrations (PNEC) are listed asresults of several studies on the hazard APIs poseto aquatic ecosystems. These PNECs are beingused by pharmaceutical industries as guidelines tothe optimal API degradation and the goals for APIcontent in their wastewater. [2] [3]As API molecules are synthetized to resistbacterial degradation, one issue regarding APIaccumulation in nature is the unsuitability of con-ventional WWTP for treatment of pharmaceuticalwastewater collected in the municipal sewers.

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Conventional WWTPs are biologic based and thetoxicity associated with API content can be harmfulto the treatment performance. [8] [5]One technology that has been proved to degradeefficiently double bound and long ramified organiccompounds, are AOPs. Advanced Oxidation isbased in Fenton Chemistry. From the severalprocesses derived from it, Photo-Oxidation asbeen successfully validated in the treatment ofpharmaceutical wastewater with API degradationvalidated. Electro-Peroxi-Coagulation uses thesame principles with expected operational costsand high efficiency in organics degradation.In this project, pharmaceutical wastewater wastreated with EPC technology. The project wasfunded by a pharmaceutical industry and thetrials occurred at the site in a pilot plant with acontinuous feed of the wastewater generated insitu.

1.2. The ChallengeAt the pharmaceutical industry site, the presenttreatment configuration is based on the steamstripping of the wastewater as a pre-treatmentbefore discharge to the municipal sewer andthermal-oxidation of high solvent waste for steamgeneration.The steam stripping column uses direct steam tostrip the solvents with a lower boiling point that thewater. The steam used in this column if producedat the thermo-oxidizer, 60% of the steam producedis directed to the steam stripping column.The direction of effluents to either the steamstripping or to thermal-oxidation is made accordingto the streams organics content, aqueous streamsare equalized and then introduced in the strippingcolumn, high solvent streams are directed tothe thermal-oxidizer. This configuration is notyet optimal, waste management wise or costswise. The pollutants are purely separated insteadof degraded. Due to the high daily volume ofwastewater, several tons of waste is shipped toexternal treatment.With the possibility of expanding the productioncapacity and the probability of increasing the site’sWWTP, the present WWTP will be revamped andthe addition of an EPC reactor was considered asa possibility due to its ability to degrade organicsinstead of separating them.The challenge presented was to compose a robustand efficient WWTP that guaranteed environmen-tal compliance, API degradation and reasonableinvestment and operational costs.At present the site produces 240 m3/day of withan average COD value of 10135 mg O2/L. Futureinstallation will be design for an average of 500m3/day of wastewater and a discharge in compli-

ance with the emission value, 1500 mg O2/L.

1.3. ObjectivesIn the described contexts, the main objectives ofthe work reported in this thesis were:• To evaluate the effectiveness of the EPC systemas a pre-treatment for pharmaceutical wastewaterpresenting a high variability in its composition;• To evaluate the effectiveness of the EPC systemas a destruction treatment for API moleculespresent amongst other organic and inorganicpollutants in the pharmaceutical wastewater;• To evaluate upstream and downstream opera-tions to complement the EPC technology to beinstalled in a pharmaceutical multipurpose factory.

2. Scientific Background2.1. Advanced Oxidation ProcessesAOPs were first defined in 1987 by Glaze as “nearambient temperature and pressure water treat-ment processes which involve the generation of hy-droxyl radicals in sufficient quantity to effect waterpurification”.[6]The main advantage of AOPs when compared toother wastewater treatment chemical technologiesis the fact that the pollutants removal in madethrough degradation instead of separation. How-ever, studies reveal that the type of AOP to be se-lected can vary with the water matrix, and in thisoptic, AOPs are yet to be fully understood. [7]AOP technologies can be broadly divided into thefollowing groups: (1) Vacuum UV (VUV) photoly-sis, (2) UV/oxidation processes, (3) Photo-Fentonprocess, and (4) sensitized APO processes. [1]The theoretical basis of AOPs is the use of ex-tremely strong oxidizing agents generated in situwithin the reaction medium. The most frequentlyused is the hydroxyl radical (•OH) which is oneof the strongest oxidants. The radicals can de-stroy most of the organic and organometallic com-pounds present in the aqueous medium throughmineralization, i.e., converting them first into sim-pler, linear chain organics and finally into CO2, wa-ter and inorganic ions. The oxidation is mostly non-selective and quick due to the high reactivity of thehydroxyl radicals.Once the hydroxyl radical is made available, thedegradation of organics can occur by dehydro-genation (Hydrogen Atom Transfer (HAT), equation1), hydroxylation (addition of an hydroxyl to an un-saturated bound or by electronic transfer (equation2).

HO• +RH → R• +H2O (1)•OH +RX → OH− +• RX+ (2)

The type of radical reaction that will occur dependson several factors that must be well explored

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and defined during AOP studies, namely, theconcentration and recalcitrance level of pollutantscan highly influence process performance.Electrochemical methods are effective for theproduction of hydroxyl radicals, either by directproduction (anodic oxidation) or indirect generationthrough a mediator such as Fe2+ in a Fenton’sreaction Environment. Anodic oxidation produceshydroxyl radicals by water oxidation on a high O2

- overvoltage anode, favouring the generation of•OH adsorbed at its surface. In electro-Fentonprocesses, H2O2 is electro-generated at the cath-ode and reacts with Fe2+ leading to the formationof the hydroxyl radicals (equation 6).

2.2. Electro-Peroxi-Coagulation Technology2.2.1 Fenton Environment

In 1984, Fenton observed that, in the presence ofH2O2 and Fe2+, hydroxyl radicals are producedthrough electron transfer. In the absence oforganic compounds, the classical Fenton’s freeradical mechanism involves the following reactions(equations 3 and 4):

H2O2(l)+Fe2+(aq)→ HO•(aq)+OH−(aq)+Fe3+(aq)(3)

H2O2(l)+Fe3+(aq)→ HO•2(aq)+H(aq)+Fe2+(aq)

(4)The first Fenton’s reaction applications in AOPinvolved the addition of Fenton’s reagent (H2O2

and Fe(II) salts) originating iron sludge from theprecipitation of iron oxyhydroxides. From this initialapproach several adaptations and techniqueswere developed and adapted to a wide range ofwater treatment situations.

2.2.2 Electro-Fenton (EF)

One of the technologies derived from Fenton’sreaction has been named Electro Fenton (EF).This is a method based on the oxidation of theorganic compounds via an indirect electrochem-ical oxidation through hydroxyl radicals, with thepossibility of generating H2O2 and Fe2+ in situ.EF is an electrochemical technique with a higheroxidation power than the simpler anodic oxidation.Oxidation occurs through the continuous supplyof the contaminated wastewater and a hydrogenperoxide solution at an acidic pH to an electro-chemical cell with O2-diffusion cathodes, wherethe two-electron reduction of oxygen takes placeaccording to equation 5, as schematized in Figure1. Iron ions (Fe2+ or Fe3+) are added to thesolution increasing the oxidation power of the gen-erated H2O2. The Fe3+/Fe2+ system provides the

basis for the metal-catalysed oxidation, namely,H2O2 oxidizes Fe2+ (equation 6) generating thehydroxyl radical and Fe3+, equation 7.

O2(g) + 2H+2e− → H2O2 (5)

H2O2 + Fe2+ → HO• +OH− + Fe3+ (6)

Fe3+ + e− → Fe2+ (7)

Figure 1: Schematic diagram of an EF cell showing the mainreactions involved in an EF process using a carbonaceous ma-terial cathode. [4]

2.2.3 Electro-Peroxi-Coagulation (EPC)

The Electro-Peroxi-Coagulation (EPC) process isbased on the use of a sacrificial iron anode thatcontinuously injects Fe2+ to the reaction solution(equaltion 8), which is further oxidized to Fe3+

through Fenton’s reaction (equation 9) generatingthe hydroxyl radical. With this electrochemicaltechnique, organic pollutants are removed both byoxidation and by coagulation with the Fe(OH)3 thatprecipitates from the excess of Fe3+ obtained fromFenton’s reaction.

Fe3+(aq)+HO•2(aq)→ Fe2+(aq)+O2H

+(aq) (8)

H2O2 + Fe2+ → HO• +OH− + Fe3+ (9)

Dosage is made with consideration to the WWorganic load and parameterized by COD measure-ments, through a given value of the ratio between[H2O2] and COD. higher concentration environ-ments, the hydroxyl radicals can be scavenged(equations 10 and 11) and sludge separationthrough gravity sedimentation can be impaired dueto O2 off-gassing (with the possibility of sludgeflotation occurring).

Fe2+(aq)+HO•(aq)→ Fe3+(aq)+OH−(aq) (10)

HO•2(aq) +HO• → H2O(l) +O2(g) (11)

The correlation between Fe2+:COD ratios andCOD removal effectiveness seems to follow the

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pattern identified for H2O2, namely, a higherFe2+ concentration generally implies higher CODremoval, but beyond certain values this effectdecreases.Again, the higher concentration of the addedreagent can result in scavenging of the hydroxylradicals, the ferrous ions promoting competitivereactions with the latter, which will be consumedas in equation 12 compromising the generation ofH2O2. In particular, the deposition of Fe(OH)3 onthe cathode can decrease the active sites for theproduction of H2O2.

Fe3+(aq) +HO•2(aq)→ Fe2+(aq) +O2H

+(aq)(12)

The hydrogen peroxide feeding method alsoaffects markedly the effectiveness of the CODremoval as it impacts on the [H2O2]/[Fe2+] ratio.Reported studies showed that the step-feed of theH2O2 solution reduced the probability of hydroxylradical scavenging and achieved higher CODremoval levels, while the single step dosage ofH2O2 resulted in a rapid and efficient generationof radicals but increased the possibility of parasitereactions of the hydroxyl radical with hydrogenperoxide.The value of pH interferes in the speciation ofFe ions in solution and in H2O2 decomposition.Several studies tested pH ranges between 2 and8 in EPC processes, but most concluded that theoptimal pH for the EPC reaction is around 3.The optimal current density should be determinedexperimentally, through a trial period of with in-creased and decreased current density values, asa better approach for each individual installation.

3. Materials and Methods3.1. Operational PlanThe EPC Pilot Plant was a lease for a 2 monthperiod, therefore the trial tests and analytical testsplans were made to maximize the data collectedand the treatment setup variations.The complete operating manual of the pilot unitas well as the P&I diagram, are not public due toconfidentiality.The Pilot Plant consisted in two containers withseveral equipment inside and adjustable connex-ions between equipment.With several equipment available at the PilotPlant, several setups were composed to combineseparation and degradation technologies prior andposteriorly to the EPC step.The upstream technologies experimented wereSteam Stripping and Electro Coagulation, thedownstream technologies experimented werePhoto-Oxidation, Electro Oxidation and ReverseOsmosis (with retreatment of the concentrate in a

second EPC batch reaction). The flow possibilitiesfor treatment at the Pilot Plant are schematized inFigure 2.

All the equipment listed above operated in recir-

Figure 2: Schematic diagram the available equipment insidethe EPC Pilot Plant and the sequence possibilities.

culation in 1m3 open tanks to prevent explosiveatmosphere formation, therefore the Pilot Plantbatch capacity was 1m3.Water was admitted in 1m3 tanks to proceed toautomatic pH correction according to the step thatfollowed. Chemical dosage was also automatic.Temperature probes indicated the temperatureinside the tanks and the Pilot Plant control systemactuated in the dosing to prevent high temper-atures – studies and manufacturer’s experienceindicated that above 50oC the reaction couldrapidly get out of the operator control.As the tanks were open and due to the presenceof organic solvents with high volatility, ventilationwas ensured to prevent explosive atmosphereformation, with the permanent opening of thecontainers doors during operation. The plant alsohad LEL indicators and above a certain point ofLEL, the Plant’s electricity was shut down as asafety measure.Operational parameters: current density, dosingmethod (on/off dosing pump), hydrogen peroxidevolume to add and reaction time; were computedby the manufacturer’s simulator that adapts thebatch reaction to the wastewater according to itsCOD value.The Pilot Plant had two feeding options: contin-uous effluent (fresh wastewater from the site’swastewater equalization tank) and simulatedeffluent (synthetic wastewater prepared fromcollected fresh wastewater with addition of specificcompounds – APIs, solvents, liquid wastes).

3.2. Analytical PlanSamples were collected according to a samplingplan regarding frequency and sampling position inthe treatment.Each trial test was grab sampled at the end of ev-ery step and samples were tested in an internallaboratory for: conductivity, pH, COD, TOC Chlo-rides and hydrogen peroxide concentration.For specific trials, wastewater was collected at the

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inlet and outlet of the Pilot Plant and analysed forseveral environmental parameters as well as forAPI content.For specific trials, wastewater was collected at theinlet and outlet of the Pilot Plant and tested for res-piratory inhibition by dissolved oxygen measure-ments in a biomass suspension in nutrient mediumbefore and after addition of the sample.The analytical tests performed internally, methodsare listed in Table 1, and externally in Tables and 23.

Table 1: Internal analysis parameters and respective analyticalmethod

Parameter Analysis Method

Chemical OxygenDemand

Merck Spectroquant R©COD cell test (300-3500mg O2/L)

Total Organic Car-bon

G&E Waters R© InnovoxTOC Analyzer (0-5000mg O2/L)

Hydrogen Perox-ide Concentration

Merckoquant R© Peroxidetest strips (1 to 100 mgH2O2/L)

Chlorides Con-centration

Merckoquant R© Chloridetest strips (500 to 3000mg Cl−/L)

Dissolved OxygenUptake Rate

HachLange R© HQ40dPortable Multi-ParameterMeter with DO (0.01 - 20mgO2/L)

Table 2: External analysis API detection methods and respec-tive quantification limits.

API AnalysisMethod

QuantificationLimit

BetamethasoneAcetate HPLC 2 microg/L

BetamethasonePhosphate HPLC 15 microg/L

Fluticasone Propi-onate HPLC 2 microg/L

Lisacline UPLC 2 microg/LMynocline UPLC 2 microg/L

Table 3: External analysis parameters for effluent and respec-tive analytical method

Parameter Analysis MethodpH MI LAQ 150.03Condutivity MI-LAQ-104-02COD ISO 6060:1989BOD5 MI LAQ 167.02BOD20 MI LAQ 167.02AOX CSN EN ISO 9562TSS MI LAQ 166.02VSS SMEWW-2540-G- 21st editionTKN SMEWW 4500-B – 21st editionNH3 MI LAQ 164.01NO2 NP EN 26777:1996NO3 MI LAQ 211.01Cl SMEWW 4500-D-21st edition

S CZ SOP D06 07 15.A (CSN 830520-16, CSN 83053 -part 31)SM4500-S2-D

Detergents CZ SOP D06 07 031 (CSN EN 903)

FOG CZ SOP D06 02 059 (based on CSN75 7506)

TotalHydro-carbon

CZ SOP D06 02 057 (based on CSN75 7505, CSN 830540-4)

Phenols CZ SOP D06 07 030 (CSN ISO 6439)TotalHeavyMetals. As MI LAQ 163.04. Cd MI LAQ 163.04

. CNCZ SOP D06 02 089.A (CSN 757415,CSN EN ISO 14403-2)/CZ SOP D0607 010 (CSN 75 7415)

. Cr CZ SOP D06 02 J06

. Cu MI LAQ 163.04

. Fe MI LAQ 147.01

. Hg EPA 245.7:2005

. Pb MI LAQ 163.04

. Zn MI LAQ 163.04

VOCCZ SOP D06 03 155 except chapter9.2 (US EPA 624, US EPA 8260,ENISO10301, MADEP 2004, rev.1.1)

Solvents DIN 38407-F9-1/ DIN EN ISO 10301-F4

MEK HS-GC-MSMEG Housemethod PI- MA-M 3-77THF HS-GC-MSDaphniaMagna CZ SOP D06 03 178 (ISO 18857-2)

SMEWW stands for Standard Methods for Exami-nation of Water and Waste Water, which is a publi-cation of the American Public Health Association.ISO stands for International Organization for Stan-dardization.

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4. Results & discussion4.1. Pharmaceutical Wastewater Characterization

The average WW levels and regulatory limits forthe critical environmental parameters were identi-fied after a thorough processing of the data regard-ing the analytical tests performed on samples ofthe continuous effluent. These values are summa-rized in Table 4, together with the established ac-ceptance criteria for the performance of the EPCtreatment technology when applied to this site’swastewater.

Table 4: EPC Reactor Acceptance Criteria for pollutant removalbased on the regulatory limits.

4.2. EPC Reactor Performance

To assess EPC Reactor performance, resultsincludes data from trials using the industrialwastewater continuously gathered at the tankfeeding the steam stripping column. Data fromsynthetic effluent will be referenced at the APIDegradation assessment and Robustness Assess-ment.Grab samples were collected at the entrance ofthe EPC and at the outlet of the UF in every trial.In principle, all the organics removal occurred atthe EPC reactor and the resulting sludge wasseparated from the treated wastewater at theultrafiltration unit.

4.2.1 Effluent Coloration

As a rapid approach, contaminated water canbe visually analyzed for turbidity and coloration.Treated water is transparent and colorless whilecontaminated water has a characteristic am-ber/green coloration and is turbid. Although thesefeatures of the effluent are no guarantee of its non-contaminated nature, experience with the site’sWW makes it possible to associate more heavilyloaded effluents with darker shades and less con-taminated effluents with lighter shades. In Figure3 is possible to identify a decrease in the colouringof the effluent through treatment.

Figure 3: Pictures of the inlet, EPC outlet (after ultrafiltration)and CAF outlet grab samples for trial test number 10 carried outon 23rd November 2016 at the EPC Pilot Plant.

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4.2.2 COD Removal

The operational parameters varied from trial totrial, and only through the review of individual re-sults from reagent ratio can allow the assessmentof the possibility of optimizing reactor perfor-mance.During the effectiveness trial tests, the com-binations of reagent ratios that resultedin higher and more consistent COD re-moval were COD/Fe/H2O2=15/1/15 andCOD/Fe/H2O2=15/1/30, Figure 4. When ana-lyzing in more detail the trials that registeredsimilar COD removal efficiencies for the sameapplied ratios, it was possible to conclude that theoptimal ratio combinations seem to be different fordifferent ranges of inlet COD.

Figure 4: COD removal efficiency values plotted against theCOD/H2O2/Fe ratios.

A more thorough study on the optimal doses anddosing method is advised when applying EPC asa treatment stage during wastewater treatment.In Figure 5, percentage removal values indicatethat the best ratios are COD/Fe/H2O2=15/1/30,while organics mass removal values suggestthat the ratios COD/Fe/H2O2=10/1/15 may bebetter suited. This difference is due to the varyingorganics load in the inlet wastewater and againreinforces the need for complementary studies.

Overall, the reactions were planned for two-hourperiods, with multi-step addition of hydrogen per-oxide to better control the radical attack process.One issue which is identifiable in Figure 5 is thatin some curves sequential points show apparentlyerratic COD level behavior. This suggests difficul-ties in collecting properly mixed, representative

Figure 5: COD removal efficiency values ( in kg of COD re-moved) for the tested COD/Fe and COD/H2O2 ratios, obtainedat 30 minutes and at 120 minutes of reaction, in the effective-ness trial tests.

effluent samples throughout the treatment.

At the end of the effectiveness trial tests, given thatorganics degradation seemed to follow an expo-nential decay curve, the decision to shorten resi-dence time at the reactor was made. Assessing theadequate reagent dosage was necessary to en-sure that the multi-step addition was occurring andavoid scavenging of the hydroxyl radicals (possiblewhen H2O2 is dosed in a single step) as well asthe raising temperature as a result of uncontrolledreactions.

Figure 6: Time course of COD degradation in all the effective-ness trial tests.

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4.2.3 Complementary Equipment

To improve the overall treatment performance, sev-eral equipment was introduced in the treatmentsetup an their performance was also assessed interms of COD removal. The summary of the con-clusions regarding the complementary equipmentare presented in Tables 5 and 6.

Table 5: COD removal efficiency values ( % of COD removed)for the complementary equipment in the EPC Pilot Plant, thatcan upgrade the overall efficiency.

Table 6: Complementary Equipments Influence on the treat-ment assessment.

4.2.4 EPC Reactor Robustness

The trials plan included the designated Robust-ness Tests, namely, trials on synthetic wastewa-ters simulating likely future changes in the site’swastewater composition or stress situations thatmimic nearmiss situations on the site’s history.

• Integration of segregated streams

At present, the liquid waste is segregated to bestfit the site’s WWTP. Considering the installationof an EPC unit on site, some of the presentlysegregated stream can be integrated in the WWTPequalization.The simulation of the integration in the treatmentof streams with an expected low organic load con-sisted in treating 1 m3 of these effluents at the EPCPilot Plant, characterizing them and evaluating thetreatment performance, as these effluents will justdilute the pharmaceutical wastewater.To simulatethe integration of presently segregated streamseffluents, these effluents were added to the phar-maceutical wastewater in ratios according to futureexpectations, considering the expected daily flowrates and equalization volumes existent at thesite’s industrial WWTP. The effluents treated were1) Condensate phase from the thermo-oxidizer’soff-gas treatment, 2) Utilities condensates and 3)COL (Change of Line) effluent. In these trials,effluent biodegradability increased and the toxixitydecreased.

• Simulation of a solvent leaks

Stress situations were simulated with addition ofkey solvents to the pharmaceutical wastewater,with the ratio mimicking the site’s incidents history,specifically, when solvent leaks occurred.The site’s incidents history with respect to solventleaks was used to simulate the addition of a leakto the pharmaceutical wastewater fed to the EPC.Regardless of the high load of solvents, the EPCperformance was within expected ranges (Table 7).

Table 7: EPC treatment of simulated solvent leaks together withthe pharmaceutical wastewater: summary of COD removal effi-ciency results.

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4.3. API DegradationDue to confidentiality issues, the quantification ofspecific API in the wastewaters from the EPC testtrials will not be presented, but Figure 7 showsthe average API removal levels including the mainAPIs tested.These averages were computed from API removalresults in tests for the treatment of synthetic efflu-ents, namely pharmaceutical wastewater supple-mented with specific amounts of API to detect theirpresence and degradation, and in tests carried outwith unsupplemented pharmaceutical wastewater.In all the tests, the API removal levels were over97% and the degradation time curves presentedthe same behavior identified for COD, with 90% ofthe API being degraded in the first 30 minutes ofthe EPC reaction.

Figure 7: Average removal for selected APIs, in trials performedat the EPC Pilot Plant using pharmaceutical wastewater with orwithout supplementation with the same APIs.

4.4. Treatment Environmental PerformanceThe biodegradability and toxicity assessment wasmade considering the discharge of the pre-treatedpharmaceutical wastewater into a downstream mu-nicipal WWTP or the alternative of introducing a bi-ological step in the industrial WWTP to completethe wastewater treatment. In either cases there isstill a final discharge into a natural water courseand effluent toxicity to aquatic environments wasassessed.Toxicity tests can measure the impact of a sam-ple on aquatic fauna and in this project the toxicitytests were done by measuring the acute toxicity ofthe treated effluent towards Daphnia magna. An-other used measure of the effluent toxicity was therespiratory inhibition on an aerobic microbial pop-ulation, determined through measurements of thedissolved oxygen uptake rate with a dissolved oxy-gen probe.The recommended emission limit is 2 toxicity units(TU), and as can be seen in Figure 8, the EPC tri-als resulted in an effluent of low toxicity. With andaverage toxicity of 1.25 Toxic Units (TU) at the out-let, treatment at the EPC provided on average a

95.8 % decrease in relation to the inlet wastewatertoxicity.

Figure 8: Inlet and outlet eco-toxicity levels, measured in toxi-city units (TU) towards Daphnia magna, for some of the effec-tiveness trials performed at the EPC Pilot Plant.

Reviewing Figure 10, it is possible to conclude thatthe treated effluent presents a decrease in respi-ratory inhibition upon treatment in the EPC pilot,which is coherent with the data on Figure 8. Thetreated wastewater was much less inhibitory to thebiomass, with respiratory inhibition level of 5 %,that the inlet wastewater, corresponding to an av-erage decrease in inhibition of 94.8 %.

Figure 9: Inlet and outlet biodegradability levels, measured asthe ratio of BOD5 to COD, for some of the effectiveness trialsperformed at the EPC Pilot Plant. The horizontal lines indicatethe minimum (yellow) and ready (green) biodegradability levels.

Figure 10: Inlet and outlet toxicity levels, measured as respi-ratory inhibition in an aerobic microbial population, for some ofthe effectiveness trials performed at the EPC Pilot Plant.

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5. Economic Analysis and ConclusionsThe effectiveness trials validated the EPC technol-ogy ability as an organics degradation techniquefit to integrate the site’s WWTP. The removalefficiencies for the relevant quality parametersachieved the objectives set in the technologyacceptance criteria. Regarding COD and TOC,the performance objective was not achieved inthe EPC alone although the presence of somedegradation and separation technology promotedan overall higher removal. These issues were con-sidered in the implementation scenarios explored.In the robustness trials, the EPC technology’sperformance maintained the trends set in theeffectiveness trials establishing the EPC reactoras a versatile treatment capable of buffering thestress situations and accept the alterations on thewastewater composition that may occur due to thesite’s expansion.API Degradation studies and environmental perfor-mance assessment, revealed that the EPC reactoris capable of efficiently degrading API moleculesand that the treated wastewater becomes morebiodegradable and has a lower toxicity than at theentrance of the treatment.Considering all this conclusions, a thorough eco-nomic analysis was made regarding treatmentoperational costs and installation investment.With a treatment cost pf 1.93 euro/kg of CODremoved, the revamped WWTP will operate incoordination with the wastewater segregation planto treat it more efficiently and at an overall lowercost than those of the present operation.In the designed WWTP - Figure 11, EPC reactor iscomplemented with a biological reactor, the 90%overall COD removal distribution is 70% COD atthe EPC reactor and 20% at biological reactor.

The evaluation of soft gains allowed the es-

Figure 11: Industrial WWTP setup.

timation of the payback period and validatedthe investment’s feasibility. This analysis wasdone considering the actual waste managementactivities carried out in 2016 and the projected

management that would have been done in thenew WWTP with the same streams and yearly flowrates.The estimated soft gains for the year of 2016,when comparing the future treatment with thepresent treatment are 603,000 euros. This valueconsiders a treatment capacity of 240 m3/day anda wastewater with 10500 mg O2=L of COD load.The future installation was designed for a higherfeed flow rate and higher organics load, thereforeit is not incorrect to consider that it will performin compliance under the considered capacity andCOD value. The expansion that motivated theWWTP revamping will be finished in five years andthe estimated timeline for the new WWTP is tobe operating in two years, therefore the paybackperiod can consider the present wastewater com-position and treatment capacity.Considering an investment of 1,462,000 eurosand soft gains of 603,000C, the future WWTP willhave a payback time of two to three years. Thedesign will be done to guarantee environmentalcompliance.

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