PNWS AWWA 2008 Annual ConferencePNWS AWWA 2008 Annual ConferenceVancouver, WashingtonVancouver, Washington
Contaminants of Emerging Concern Contaminants of Emerging Concern in Water and Wastewater Treatmentin Water and Wastewater Treatment
John BratbyJohn Bratby
Brown and CaldwellBrown and Caldwell
Contaminants of Emerging Concern in Contaminants of Emerging Concern in Water and Wastewater TreatmentWater and Wastewater Treatment
Nature of CECsNature of CECs Removal mechanisms of CECsRemoval mechanisms of CECs Removal efficiencies of CECs during Removal efficiencies of CECs during
treatmenttreatment Do membrane bioreactors provide Do membrane bioreactors provide
enhanced removal of CECs?enhanced removal of CECs? Other advanced treatment for higher Other advanced treatment for higher
levels of CEC removallevels of CEC removal
Recent AP articleRecent AP article ““Mary Buzby -- director of environmental technology for drug Mary Buzby -- director of environmental technology for drug
maker Merck & Co. Inc.: maker Merck & Co. Inc.: "There's no doubt about it, pharmaceuticals "There's no doubt about it, pharmaceuticals are being detected in the environment and there is genuine concern that are being detected in the environment and there is genuine concern that these compounds….could be causing impacts to human health or to these compounds….could be causing impacts to human health or to aquatic organisms.“aquatic organisms.“
Recent laboratory research has found that small amounts of Recent laboratory research has found that small amounts of medication have affected human embryonic kidney cells, medication have affected human embryonic kidney cells, human blood cells and human breast cancer cells. The human blood cells and human breast cancer cells. The cancer cells proliferated too quickly; the kidney cells grew too cancer cells proliferated too quickly; the kidney cells grew too slowly; and the blood cells showed biological activity slowly; and the blood cells showed biological activity associated with inflammation.associated with inflammation.
Some scientists stress … that the documented health Some scientists stress … that the documented health problems in wildlife are disconcerting.problems in wildlife are disconcerting.
Removal Pathways of Groups of CECs Removal Pathways of Groups of CECs in Wastewater Treatmentin Wastewater Treatment
Steroid compoundsSteroid compounds PhytoestrogensPhytoestrogens SurfactantsSurfactants Pesticides, herbicides, fungicidesPesticides, herbicides, fungicides Polyaromatic compoundsPolyaromatic compounds Organic oxygen compounds (Bisphenol A, Organic oxygen compounds (Bisphenol A,
Phthalates, Dioxins, Organotins)Phthalates, Dioxins, Organotins)
Potency of Steroid CompoundsPotency of Steroid Compounds
Estradiol 1 ng/l <0.2 - 3 ng/l
Ethinyl estradiol 0.1 ng/l <0.2 - 3 ng/l
Nonylphenol 14,000 ng/l <80 - 923 ng/l
Bisphenol A 25,000 ng/l 8 - 33 ng/l
(German study - Berlin-Ruhleben WWTP - Hansen et al, 1998)
Lowest observed effective concentration (LOEC) -
Rainbow troutEDC
WWTP effluent concentrations
SurfactantsSurfactants Main surfactants of interest for ED are the alkylphenols (APs) and Main surfactants of interest for ED are the alkylphenols (APs) and
their ethoxylates (APEOs) – particularly the nonylphenol (NP) their ethoxylates (APEOs) – particularly the nonylphenol (NP) compoundscompounds
Alkyl Phenol Ethoxylates (APEO) widely used in industries as well Alkyl Phenol Ethoxylates (APEO) widely used in industries as well as commercial and household functionsas commercial and household functions
Detergents, lubrication, defoamers, emulsifiers, paints, pesticidesDetergents, lubrication, defoamers, emulsifiers, paints, pesticides Cleaners for machinery, metal working, textiles, and personal productsCleaners for machinery, metal working, textiles, and personal products
Nonylphenol ethoxylate is the most commonNonylphenol ethoxylate is the most common APEOs tend to be degraded to more potent endocrine disrupting APEOs tend to be degraded to more potent endocrine disrupting
compounds during wastewater treatmentcompounds during wastewater treatment The ethoxylates can be degraded to produce NP which is more The ethoxylates can be degraded to produce NP which is more
persistent and toxic than the ethoxylatespersistent and toxic than the ethoxylates Highest freshwater concentrations of NP observed near WWTPs, Highest freshwater concentrations of NP observed near WWTPs,
pulp mills, and regions of heavy industrypulp mills, and regions of heavy industry
PesticidesPesticides Largest group of EDCsLargest group of EDCs DDT, dieldrin, 2,4-D, tributyltin, atrazine, metolachlor, DDT, dieldrin, 2,4-D, tributyltin, atrazine, metolachlor,
cyanazine, alachlorcyanazine, alachlor All herbicides, fungicides, pesticidesAll herbicides, fungicides, pesticides Atrazine one of the most difficult to removeAtrazine one of the most difficult to remove
Understand Properties to Understand Properties to Predict Physical ProcessesPredict Physical Processes
Kow values are an indicator of hydrophobicity, and have been used as a surrogate for removal during water treatment
Property Potential Units Low High
Water Solubility Dissolving mg/l <1 1000
Henry's Law ConstantEvaporation/ Volatilization atm m3/mole >10-2 <10-7
Organic/Carbon Partition Coefficient
Degradation log Koc <3 >3
Log octanol/water partition
Sorption log Kow <2.5 >4
CEC removal in Biological Treatment CEC removal in Biological Treatment – Dependent on parameters such as:– Dependent on parameters such as:
Temperature Sludge age, SRT HRT Influent concentrations Co-metabolite transformations Treatment type (AS, TF, MBRs)
Probably lower EDC concentrations from MBR systems due to retention of both particulate and colloidal material. Membrane systems appear to form colloid complexes to a greater extent than conventional systems
WWTP Removals for Select EDCsWWTP Removals for Select EDCs
Trickling filter (TF) 90%
Activated sludge (AS) 96%
TF-AS 99%
NP AS - High load non-nitrifying 37%
As - Low load nitrifying 77%
AS - High load non-nitrifying -3%
AS - Low load nitrifying 31%
AS - High load non-nitrifying -5%
AS - Low load nitrifying 91%
AS - High load non-nitrifying 78%
AS - Low load nitrifying 98%
AS - High load non-nitrifying -5%
AS - Low load nitrifying 91%
Steroid estrogen - E1 AS - SRT 6 to 11 days, 20oC 75 to 98%
Steroid estrogen - E2 AS - SRT 6 to 11 days, 20oC 75 to 94%
Sand filtration - Microfiltration 70%
Reverse osmosis 95%
Primary treatment -5%
Secondary treatment 91%
Tertiary treatment 98%
Triazines Conventional two stage <40%
Organotins
Treatment Process
NP6EO
NP2EO
17 estradiol/17 ethinylestradiol (removals from influent)
EDC Removal Efficiency
PCB
NP1EO
NP2EO
Removals of E1 and E2 Removals of E1 and E2 reduced to 64 to 94% at reduced to 64 to 94% at 1515ooC (SRT 6 to 11 d)C (SRT 6 to 11 d)
Removal Rates of Steroid Estrogens at Removal Rates of Steroid Estrogens at Varying Retention TimesVarying Retention Times
From: Johnson A.C., Belfroid From: Johnson A.C., Belfroid A., Di Corcia A. (2000)A., Di Corcia A. (2000)
E1 Loss E2 Loss E1 Loss E2 Loss
18-hour HRT 6-day SRT
64% 92% 75% -
18-hour HRT 11-day SRT
94% 98% >98% -
26-hour HRT 20-day SRT
66% >75% 98% >94%
13 - 15 ºC 18 - 19 ºC
Influent and Effluent Concentrations of Influent and Effluent Concentrations of Alkylphenolic Compounds in WWTPsAlkylphenolic Compounds in WWTPs
WWTP Location
Number of
WWTPs
Type of Plants
Influent Concentration
(µg/l)
Effluent Concentration
(µg/l)
<10 - 35 NPSwitzerland 3 24 - 133 NP1EO
<10 - 70 NP2EO
14 NP 8 NPSwitzerland 1 18 NP1EO 49 NP1EO
18 NP2EO 44 NP2EO
Switzerland 5Mechanical -
biological844 - 2250 NPEO + NP 40 - 369 NPEO + NP
Switzerland 11 1090 - 2060 NP 240 - 760 NP
U.K. 12 <0.2 - 330 NP
Italy 1Mechanical -
biological800 NPEO 8 NPEO
U.S. 1 143 - 272 NPEC
Mechanical - biological
NTA – Nitrilotriacetic acid – considered as a detergent builder in place of phosphates
Acclimation Times Required for NTA Acclimation Times Required for NTA Removal With Activated Sludge TreatmentRemoval With Activated Sludge Treatment
From: Rossin A.C., Lester J.N., From: Rossin A.C., Lester J.N., Perry R. (1982)Perry R. (1982)
SRT (days)
NTA Influent Concentration
(mg/l)
MLSS (mg/l)
Acclimation Time (days)
4 7.5 1514 15
4 15 - 20
9 7.5 3049 12
9 15 - 16
12 7.5 3536 6
Comparison between MBR and CAS systemsComparison between MBR and CAS systems(from Scruggs C. (from Scruggs C. et alet al., WE&T, March 2005; Mansell ., WE&T, March 2005; Mansell et alet al., WEFTEC, 2005)., WEFTEC, 2005)::
Hormones: Removal comparison between MBR Hormones: Removal comparison between MBR and CAS systemsand CAS systems (from Mansell (from Mansell et alet al., WEFTEC, 2005)., WEFTEC, 2005)::
Granular activated carbon
Advanced oxidation
Reverse osmosis
CEC removal: CEC removal: Advanced treatment Advanced treatment processes following secondary treatmentprocesses following secondary treatment
Coagulation or Chemical PrecipitationCoagulation or Chemical Precipitation Most compounds of concern are relatively polar (KMost compounds of concern are relatively polar (Kowow
values < 3)values < 3) Neither alum or iron coagulation or lime softening Neither alum or iron coagulation or lime softening
effective for atrazine or antibiotic removalseffective for atrazine or antibiotic removals Coagulation ineffective with several pharmaceuticals Coagulation ineffective with several pharmaceuticals
and with several pesticidesand with several pesticides Some pesticides (PAHs pyrene, fluoranthene and Some pesticides (PAHs pyrene, fluoranthene and
anthracene) removed ~50% by coagulationanthracene) removed ~50% by coagulation Coagulation only expected to remove hydrophobic Coagulation only expected to remove hydrophobic
compounds associated with particulate or colloidal compounds associated with particulate or colloidal materialmaterial
EDCs and PPCPs not associated with colloidal or EDCs and PPCPs not associated with colloidal or particulate material very poorly removed (<10%)particulate material very poorly removed (<10%)
AdsorptionAdsorption Activated carbon (AC) effective for many different Activated carbon (AC) effective for many different
pesticides, PPCPs and EDCspesticides, PPCPs and EDCs Hydrophobic interactions dominant mechanism (weak Hydrophobic interactions dominant mechanism (weak
ion exchange interactions also contribute to ion exchange interactions also contribute to adsorption)adsorption)
AC can remove neutral organic compounds with AC can remove neutral organic compounds with hydrophobic compounds (logKhydrophobic compounds (logKowow>2)>2)
NOM in water competes for adsorption sites and NOM in water competes for adsorption sites and decreases AC effectiveness for micropollutantsdecreases AC effectiveness for micropollutants
PAC can be effective; GAC probably more efficientPAC can be effective; GAC probably more efficient PAC could be good emergency measure at WTPs, PAC could be good emergency measure at WTPs,
particularly during low streamflow, and with upstream particularly during low streamflow, and with upstream wastewater dischargeswastewater discharges
Membrane FiltrationMembrane Filtration Most organic EDCs and PPCPs are 150 to 500 Most organic EDCs and PPCPs are 150 to 500
daltonsdaltons Most can be removed in RO and tight NF Most can be removed in RO and tight NF
membranesmembranes Microfiltration and ultrafiltration will only remove Microfiltration and ultrafiltration will only remove
those EDCs and PPCPs associated with colloidal those EDCs and PPCPs associated with colloidal and particulate matterand particulate matter
Polar and charged compounds that interact with Polar and charged compounds that interact with membrane surfaces will be better removedmembrane surfaces will be better removed
Hydrophobicity also affects removals. Removals Hydrophobicity also affects removals. Removals by RO and NF membranes correlates with logKby RO and NF membranes correlates with logKowow
Effectiveness of Effectiveness of Treatment Treatment
Processes with Processes with Some CECsSome CECs
Effluent to be treated
Off-gasE
fflu
ent
Treatment Targeted CommentsProcess EDCs
GAC
APs, APEOs, PCP, methoxychlor,
endosulfan, diethyl phthalate, di-(2ethyl
hexyl) phthalate, PCBs
EPA BAT for some
contaminants
Reverse osmosis
Alkylphenol polyethoxy
carboxylates (APnECs), PCP
Most EDC compounds
removed by RO.
UV+catalystAPs, bisphenol A, E2, EE2, lindane,
2,4-D,
Ozone+H2O2 Atrazine2 min. EBCT.
EU regs may not be met
Coagulation, sedimentation and filtration
2,3,7,8 TCDDAdsorbed to floc
particles
General removal efficiencies of General removal efficiencies of treatment processestreatment processes
EDC Classification
Coagulation/ Flocculation
Softening/ metal oxides
CL2/ ClO2
UVOzone/ AOPs
Activated Carbon
BAC NF RO
Pesticides <20% 70-90% 70->90% >90% 20->90% >90% >90% 70->90% >90%
Industrial chemicals
<20-40% <20-40% <20% >90% 40-90% >90% >90% >90% >90%
Steroids <20% <20-40% >90% >90% >90% >90% >90% 70->90% >90%
Metals 40-90% 40-90% <20% <20% <20% 70-90% 70-90% 70->90% >90%
Inorganics <20% 70-90% <20% <20% <20% <20-40% 40-70% 70->90% >90%
Organometalics <20-40% <20-40% <20-70% 40-90% 20->90% 70->90% 70->90% 70->90% >90%
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