Water Treatment

CE 326 Principles of Environmental Engineering

March 5, 2010

Tim Ellis, Ph.D., P.E.

Announcements:

– Water Chemistry 2 problems due today

Maximum Contaminant Levels for Inorganic Compounds

ContaminantExisting MCL (mg/L) MCLG (mg/L)

ArsenicAsbestosBariumCadmiumChromiumLeadMercuryNitrate (as N)Nitrite (as N)SeleniumThallium

0.017 million fibers/L

2.00.005

0.10.015 TT

0.00210.01.0

0.050.0005

07 million fibers/L

2.00.0050.10

0.00210.01.00.05

0.002

http://www.epa.gov/safewater/contaminants/index.html

Organic SubstancesOrganic Substances

• Volatile Organic Compounds. Volatile Organic Compounds. – Compounds which are characterized by high Compounds which are characterized by high

v_______ are classified as volatile organic v_______ are classified as volatile organic compounds (VOCs). compounds (VOCs).

– VOCs may have particular adverse health VOCs may have particular adverse health effects. effects.

– They are a result of industrial, commercial, They are a result of industrial, commercial, and agricultural activity. and agricultural activity.

– Many are s_______ or additives (e.g., paint Many are s_______ or additives (e.g., paint thinners).thinners).

olatility

olvents

Synthetic Organic CompoundsSynthetic Organic Compounds

• Organic chemicals of an a________________ Organic chemicals of an a________________ origin are termed synthetic organic origin are termed synthetic organic compounds (SOCs). compounds (SOCs).

• Like VOCs, SOCs may have particular Like VOCs, SOCs may have particular adverse health effects and are a result of adverse health effects and are a result of – industrial, industrial, – commercial, and commercial, and – agricultural activity. agricultural activity.

• Many SOCs are h__________, p___________, Many SOCs are h__________, p___________, or i______________.or i______________.

nthropogenic

erbicides esticidesnsecticides

Disinfection ByproductsDisinfection Byproducts• During disinfection of drinking water, chemical During disinfection of drinking water, chemical

oxidants kill disease causing organisms oxidants kill disease causing organisms (p_________) but can also create toxic organic (p_________) but can also create toxic organic compounds. compounds.

• These are termed disinfection byproducts (DBPs).These are termed disinfection byproducts (DBPs).• The most common source of DBPs is c__________ The most common source of DBPs is c__________

or b_________ of water containing organic matter. or b_________ of water containing organic matter. • This often results in trihalomethanes (THMs), the This often results in trihalomethanes (THMs), the

most common of which are: most common of which are: – Chloroform (CHClChloroform (CHCl33))– Bromoform (CHBrBromoform (CHBr33))– Bromodichloromethane (CHBrClBromodichloromethane (CHBrCl22))– Dibromochloromethane (CHBrDibromochloromethane (CHBr22Cl)Cl)

athogens

hlorinationromination

LegislationLegislation

• SDWA of 1974SDWA of 1974– The S____ D_________ W_____ A___ (SDWA) was The S____ D_________ W_____ A___ (SDWA) was

signed into law by President Gerald Ford in 1974. signed into law by President Gerald Ford in 1974. – It established minimum national standards for It established minimum national standards for

drinking water to protect public health. drinking water to protect public health. – The act established p___________ standards which The act established p___________ standards which

specified maximum contaminant levels (MCLs) for specified maximum contaminant levels (MCLs) for individual contaminants suspected of having an individual contaminants suspected of having an adverse affect on public health.adverse affect on public health.

– The act also established s__________ standards The act also established s__________ standards relating to tastes, odors, and appearance of drinking relating to tastes, odors, and appearance of drinking water.water.

– SDWA set a timeline for the promulgation of SDWA set a timeline for the promulgation of standards with a review every three years.standards with a review every three years.

afe rinking ater ct

rimary

econdary

SDWA Amendments of 1986SDWA Amendments of 1986• By the 1980s, a number of contaminants had yet to be regulated, and By the 1980s, a number of contaminants had yet to be regulated, and

on June 19, 1986 President Reagan signed into law the 1986 on June 19, 1986 President Reagan signed into law the 1986 Amendments to the SDWA.Amendments to the SDWA.

• Major aspects of the 1986 Amendments to the SDWA included:Major aspects of the 1986 Amendments to the SDWA included:– C____________ revisions to drinking water regulations in a timely C____________ revisions to drinking water regulations in a timely

fashion.fashion.– Definition of a t___________ t___________ for each contaminant Definition of a t___________ t___________ for each contaminant

regulated.regulated.– Requirement of a treatment technique where it is not feasible to Requirement of a treatment technique where it is not feasible to

ascertain the level of a r___________ c______________ascertain the level of a r___________ c______________– F___________ r_____ for surface waters (Surface Water Treatment F___________ r_____ for surface waters (Surface Water Treatment

Rule, SWTR).Rule, SWTR).– D____________ of all water supplies.D____________ of all water supplies.– Prohibition on the use of l_____ products on conveyance Prohibition on the use of l_____ products on conveyance

systems.systems.– Requirement for the protection of g__________ sources.Requirement for the protection of g__________ sources.

• The SDWA directed EPA to set up several classes of compounds for The SDWA directed EPA to set up several classes of compounds for which regulations are to be developed and to establish a timeline for which regulations are to be developed and to establish a timeline for development of the regulations.development of the regulations.

•

ompulsory

reatment echnique

egulated ontaminantiltration ule

isinfectionead

roundwater

SDWA Amendments of 1996

• On November 29, 1996, the Senate passed a bill to On November 29, 1996, the Senate passed a bill to r_____________ the SDWA. r_____________ the SDWA.

• This bill contained several amendments to the This bill contained several amendments to the regulations which would l_______ some of the regulatory regulations which would l_______ some of the regulatory burden on water utilities, especially small systems. burden on water utilities, especially small systems.

• It bill passed the House on June 25, 1996 and both It bill passed the House on June 25, 1996 and both houses on August 2, 1996. houses on August 2, 1996.

• These amendments l_______ EPA into a 1998 deadline for These amendments l_______ EPA into a 1998 deadline for issuing a DBP rule and enhanced SWTR.issuing a DBP rule and enhanced SWTR.

• Subsequent r_______ and r_________ to current Subsequent r_______ and r_________ to current standards is required every six years.standards is required every six years.

eauthorize

essen

ocked

eview evisions

Contaminant Candidate List

• Currently, EPA has drinking water regulations for more than ____ contaminants.

• The SDWA required EPA to maintain a list of u__________ contaminants. EPA uses this list to prioritize research and data collection efforts to determine whether to regulate a given contaminant.

• In February 2005, EPA published its second list of contaminants, the c______________ c_________ l____ (CCL). In September 2009 EPA published C____.

90

nregulated

ontaminant andidateistCL3

EPA LINKS

• For the current list of standards see: http://www.epa.gov/safewater/contaminants/index.html

• for the time line of promulgation, see: http://www.epa.gov/safewater/contaminants/pdfs/contam_timeline.pdf

• for the contaminant candidate list see: http://www.epa.gov/safewater/ccl/ccl2.htmlhttp://www.epa.gov/safewater/ccl/ccl3.html