THMFINAL

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
1
Arizona State University West Lauren O.
Disinfection By-Products Trihalomethanes in the City of Phoenix
CHCl3 CHBr3 CHBr2CL CHBrCL2
Abstract
Knowledge on the generallandscapeofCity of Phoenix “safe-yield” goals that will entail six treatment
plants and ultimately the regulation of disinfectant by products (DBPs) in the formation of trihalomethanes
(THM). Quantitative information is important in determining the maximum contaminantlevel (MCL)in
orderto follow the EPA Stage 2 Disinfectants/Disinfection By-Product Rule. This rule is notso “area-
specific” to the level of THM’s in a particular geographic area,butpopulation dependentas too much
ingestion can have mutagenic effects. The fate of THM and degradation pathways indicate mostly
volatization and half-life of >1 to 65 days in water with persistence of chloroform being highestand
bromoform lowest. Comparative studies in Haiti and Westminster emphasize the use of chloramines
instead of chlorines to result in free radicals. Modeling effective routes of mitigation have eliminated
ozonation to be limited to use in aquifers for recharged water.While redox conditions can suggestthe
bromination of THM’s, bromine substitution is bestused in treating seawater desalination. Energy-
intensive mitigation techniques are currenttechnology in such examples ofgranularactivated carbon,
aeration and biofilters. The promising newertechnologyis a greenerapproach thatuses solarpowered
mixing reducing THM levels to 71 ug/L to 46 ug/L.

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
2
The water managementplan in the Phoenix Sonoran Desertincorporate an area of 546 square miles.
Since there is an average precipitation of less than 8 inches peryear, Phoenix is noted as an area in a
consistentstate of drought.The landscape formanaging wateris extremely crucial and founded in
massive-scale facilities for storage and distribution projects that fall within the scope ofenvironmental
regulations for the Phoenix Active ManagementArea (just one of the several water planning and
regulating areas that follow the 1980 GroundwaterCode). According to the City of Phoenix water services
site, the goalis to implement“safe-yield” by 2025 by balancing groundwaterwithdrawals with recharged
water from aquifers. GroundwaterWells, Reclaimed WaterUtilization, 6000 miles of water mains over the
network of six treatment plants will facilitate to meetthe maximum daywater demands.Maximum peak
hourdemands are addressedthrough reservoirs,boosterstations, and pressure reducing valves to
provide emergencycapacity. Conservation requirements underthe GroundwaterCode are enforceable in
a series of five managementplans where proactive measures in the Arizona Assured Water Supply
(AWS) Rules became effective in 1995 to demonstrate 100 years of renewable water supplyfor
development. Table 1-1 provides the currentcapacities of the six treatment plants. (Water Services Site,
City of Phoenix,2011)

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
3
Table 1-1.
Facility Verde ValVista DeerValley 24th Street Union Hills Lake Pleasant Wells
CurrentCapacity (mgd) 50 130 150 140 160 80 28
Total mgd 739
It is noteworthy to considerthat water and sustainability are still considered critical now yet also in the
future with newertechnologies as the ecologyof commerce evolves since historical roots. Considerthe
following excerpt:
“The first documented drinking watertreatment can be found in Egyptian hieroglyphics,describing
procedures to purify water. The basic principles were the same then as they are today: boiling, chemical
treatment, and filtration were recommended treatments [Calderon,2000].”(Lantagne,2001).
Trihalomethanes (THM’s ) were first discovered in 1974.Manystudies were conducted in the 1970s;
THMS’s were the first of disinfection by-productDBP’s , it was thus regulated on Nov. 29, 1979 and limits
were established. THM are carcinogenic and can causeadverse pregnancyoutcomes.(Farren,2003).

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
4
Mutagenic activity was associated with an array of halogenated compounds and thus,spurred research of
35 waste treatment centers THM’s accounted for 50%on a weigh basis,25% accounted for haloacetics,
and aldehydes accounted for 7%. (Lily et al, 1997) According to the EPA website, some people who drink
water containing total trihalomethanes in excess ofthe MCL over manyyears could experience liver,
kidney, or central nervous system problems and increased risk ofcancer.
Therefore, with this background setfor newdevelopment,inevitably among all the removalof
environmentalcontaminants, trihalomethanes (THM) even moreso than haloacetic acids (HAAS) remain
a perpetualconcern as a result of disinfection byproducts, namely chlorine that has been added to prior to
discharge treat organic matter. Thus, heavily chlorinated to subsequentlydechlorinated.Organic
requirements of The Safe Water Drinking Act (SWDA) passed in 1987 is the same for surface water and
groundwater,and thus stringent requirements are imposed on drinking water standard revisions. Total
organic halide (TOX) is a speciation of THM )that can fluctuate by water quality and disinfection
conditions, yet the four trihalomethanes of concern are trichloromethane,bromoform,
bromodichloromethane,dibromochloromethane.
THM is related to non-pointsources,such as urban and land use;However,pointsources such as septic
systems are also associated with THM. These sources are more anthropogenic in nature. Eighty parts per
billion is the maximum contaminantlevel (MCL) allowed yet levels can vary with the water temperature,

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
5
pointof chlorination,seasonalwater supply,higherhumic acid concentration,higherpH (increase),higher
temperature, quantity of chlorine added,pointof chlorination,time in distribution system and other
treatment factors. (Latagne,2001) Rates of attenuation in THM can be used to determine reduction,yet
this method is highly dependenton geochemicalenvironments such aquiferstorage and recovery (ASR)
such as in the example of a reclaimed water ASR in South Australia (Pavelic, 2005).
This is a concentration limit that has been lowered significantly in the City of Phoenix.Generally, where
there is a high organic matter content, such as rivers and lakes,THM’s are generallyhighestin its use
towards 1)surface water that contains microbiologicalorganisms 2)treated water that has left the plantvia
main water pipes. (Dion, 2009). Chlorination is necessaryto preventoutbreak of waterborne diseases
such as cholera and typhoid fever, therefore the risks of outbreak without properdisinfection far outweigh
the risks from THM. It is difficult to find a particular point-source ofTHM, as pipelines extend along the
breadth of the city and thus a pointof chlorination can exist at the final destination, yet urban areas can
include such lands originally used for nitrate removal i.e. Tres Rios Wetland at 91st WWTP.
Although much is known aboutthe disinfection process,much less knowis the fate of THM’s. THM half-
lives varied from <1 to 65 days with the result of cholorform at its highestand bromoform at its lowest.
(Pavelic, 2005) Degradation pathways include nitrifying biofilters, bromine substitution, granularactivated
carbon and cometabolism. .(Pavelic, 2005) The EPA has set its standards for WTP’s systematically (80

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
6
parts per billion) according to the Stage 1 Disinfectants/Disinfection By-Products Rule in 2003.Stage 2
Disinfectants/Disinfection By-Products in 2006 promulgated a minorcorrection in the method of analysis of
taking dualsample sets every 90 days in water systems serving 500 – 9,999 for compliance.
. Nitrosomonas europaea is an ammonia-oxidizing bacteria in biofilters that in batch culture
cometabalized. (Wahman,2005).Cometabolism is the simultaneous degradation oftwo compounds
where the secondarysubstrate is dependentupon the first; Subsequently, an enzyme can oxidize
pollutants such as chlorinated solvents and be used as a biologicalapproach to degradation ofhazardous
solvents. (Wahman,2011).
Comparative studies with an experimentin WorcesterPolytechnic Institute in December2001 madethe
following observation that chloroform was four times higherthe bromodichloromethane.(Latagne,2001).
The resulting conclusion in reducing THM is based on the latter measurable conditions and indicate that
using chloramines instead offree chlorines is more effective. Hence,in Haiti, trihalomethane formation in
rural household waterfiltration systems began concluding thatonly chloroform concentrations are
important; In addition, methods in Haiti also concluded thatsuch methods as bromine substitution were
more applicable in seawater.It was found that bromide is found in ocean waters nearthe ocean,and
therefore bromine is a more effective halogen substituting agentand can increase total THM yield in the

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
7
desalination process.(Baribeau etal,2006) Furthermore,granularactivated carbon is a common to filter
THM adsorption of CHBrCL2 and CHBr2Cl were higherthan cholorform. (Dion, 1997)
Mitigation practices for THM can include ozonation,sprayaeration, and Solar Bee mixers that eliminate
short-circuiting and thermal stratification while ensuring uniform distribution of disinfectant. Nevertheless,
ozonation is rarely used exceptin aquifer recharge,and mostgroundwaterrecharge is done with
chlorination. Furthermore,total organic halide (TOX) is a speciation of disinfection-by-products and
nonvolatile, whereas THM volatize. Neither active norpassive sampling apply. DBP’s Treatment of THM’s
involve reducing chlorine through enhanced coagulation,increasing the rate of coagulants such as ferric
instead of alum coagulants,and decreasing Ph levels to a 4 or 5, and reverse osmosis. (G.A Boorman,
1993)
New technologyis evidentin Yuma’s potable water storage tanks of 3MG. The tanks also serve as
colorful murals in the locallandscape.Located in an isolated
FIG. 1

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
8
area,the tanks are unique and creatve in the green approach thatthey are solar. Circulating tank water
allows the average concentration to drop from 21ug/L to 46ug/L.
In summary, the potential to have an average concentration of 46 ug/L in the MCL of THM through a
sustainable endeavorsuch as the Solar Bees creates an evolutionary example ofengineering through
renewable energysources thatcould satisfy cost- effective solutions in the future. Environomics discusses
the “economyof the environment”that could potentially eliminate pastmitigation techniques such as in
this example in Yuma to reduce THM’s with newertechnology. While this is experimental,current
mitigation techniques have been refined with granularactivated carbon and sprayaerators.Insofar,
aeration removalrates are 99.5 % in posttreatment of THM . Chlorine contactbasins,storage tanks,
redesign in influent piping and adding a spray nozzle system are the mostcost-effective currently. In
conclusion, much is known and published aboutTHM to meet EPA standards (Stage 2) in its reduction
and control, degradation pathway (volatization), a half-life of up to 65 years, and the propensity to use
chloramine instead of chlorination. Therefore, it will be interesting and noteworthy to “by-pass” such
energy-intensive mitigation techniques and pilot-testing assessments.Above all, Solar Bees are also
“picture perfect” artwork.

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
9
REFERENCES:
Baribeau,H., Boulos,L., Haileselassi, H., Crozes,G., Singer, P.C., Nichols, C., Schlesinger,S.A., Gullick,
R.A., Williams, S.L., Williams, R.L., Fountleroy, L., Andrews S.A. and Moffat, E. (2006).Formation and
Decay of Disinfection Byproducts in the Distribution System, AWWARF #2770
Brooke,Ethan; Collins, M. Robin. ( October 2011)Posttreament Aeration to Reduce THM. Journal-
American WaterWorks Association, v. 103 (10)84-86.
Dion-Fortier Al, Rodrigeuz MJ, Serodes J, Proulx F. (April 2009)Impact of water stagnation in residential
cold and hot water plumbing on concentrations of trihalomethanes and haloacetic acids. WaterRes.Jul; v.
43 (12) : 3057 – 66
Lantagne,DanielS.(2001). Trihalomethane Formation in RuralHousehold WaterFiltration.
Massachusetts Institute Technology,DepartmentofCivil and EnvironmentalEngineering, 43-46.
Lilly, D., Patrick, Ross, M., Pegram,Rex., (1997).Trihalomethane Comparitive Toxicity: Acute Renaland
Hepatic Toxicity of Chloroform and BromodicholoromethaneFollowing Aqueous Gavage.Fundamental
and Applied Toxicology, v.40,101-110
Pavelic P, Nicholson BC, Dillon PJ, Barry KE. (2005).Fate of disinfection by-products in groundwater
during aquifer recovery with reclaimed water. J Contam Hydrol, May; 77 (4): 351-73
G.A. Boorman.(1999) Drinking water disinfection byproducts:review and approachto toxicity evaluation.
Environmental Health Perspectives, Feb;107 (Suppl1)207-217.
Rostad, Colleen. (2013)Fate of Disinfection By-Products in the Subsurface. Science for a Changing
World.USGS Groundwater Information.

Lauren Overman
CHM 302 Spring 2015
Term Paper
Trihalomethanes
10
Wahman,D.G., Kirisits, M.J., Katz, L.E. and Speitel, G.E. (2011)Ammonia-Oxidizing Bacteria Biofilters
Removing Trihalomethanes Are Related to Nitrosomonas oligotropha. Applies and Environmental
Microbiology 77(7),2537-2540
Wahman,David G, Katz, Lynn E., Speitel Gerald. (2005).Cometabolism of Trihalmethanes by
Nitrosomonas europea. Applied and Environmental Microbiology 71(12),7980-7986
doi: 10.1128/AEM.71.12.7980-7986.2005

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