Drinking Water

1
Drinking Water Wastewater Regulation and
Treatment
2
Drinking Water Regulations

• 1893 - Interstate Quarantine Act
• Result Prohibition of Common Drinking Cup on
  Interstate Carriers created a market for Dixie
  cups
• 1914 - Microbiological Standard
• 2 coliforms / 100 ml
• 1925 - New Microbiological Standard
• 1 coliform / 100 ml
• 1942 - Maximum Concentrations for Constituents
• Lead Fluoride Arsenic
• Selenium Barium Hexavalent Chromium
• Copper Magnesium Iron Manganese
• Zinc Chloride Sulfate
• Phenolics Total Solids Alkalinity
• Phenol carbolic acid, addition of methyl group
  forms cresols, o, m, or p

3
Drinking Water Regulations

• 1962 Limits for
• Alkyl benzene sulfonates (synthetic detergents)
• Carbon-chloroform extract (organic residues)
• Adsorption on activated carbon, chloroform
  extraction, gravity quantification
• Barium Cadmium Cyanide
• Nitrate Silver Radioactivity
• Safe Drinking Water Act of 1974
• Enacted over concern about organic materials in
  drinking water
• Established Maximum Contaminant Levels (MCLs) for
  several substances Enforceable
• Federal Guidelines - Secondary MCLs (SMCLs),
  Nonenforceable

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1975 - National Interim Primary Drinking Water
Regulations

• Amended repeatedly, now include
• Microbiological Contaminants
• Total and Fecal coliforms, E. coli, Turbidity
• Radioactive Contaminants
• Beta/photon emitters, Alpha emitters, Combined
  radium
• Inorganic Contaminants
• 15 elements or materials
• Synthetic Organic Contaminants including
  Pesticides and Herbicides Volatile Organics
• 54 compounds and groups of compounds

5
Drinking Water Treatment
6
Groundwater Treatment Options
7
Surface Water Treatment Options
8
Drinking Water Treatment Units or Processes

• INTAKES
• AERATION
• COAGULATION FLOCCULATION
• CLARIFICATION
• FILTRATION
• DISINFECTION
• SOFTENING
• TASTE ODOR CONTROL
• IRON MANGANESE REMOVAL
• TRACE METALS ORGANICS

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AERATION(Usually for Groundwater)

• ADDS OXYGEN
• REMOVES
• Carbon Dioxide Hydrogen Sulfide
• Methane Taste Odors
• REMOVAL MAY BE BY
• Oxidation Volatilization
• Iron Manganese Organics

10
Coagulation, Flocculation Clarification

• Coagulation changes the electrical charge of
  suspended particles and colloids allows
  attachment to each other. Coagulants are usually
  cations Alum, Ferric Sulfate, Lime (CaO)
• Chemical/Physical process of mixing special
  purpose chemical from flow and removing the
  resulting product
• Silts/Clays, Viruses, Bacteria
• Fulvic Humic Acids, Minerals, Organic
  Particulates
• Flocculation is the agglomeration of particles
  into settleable particles
• Clarification - sedimentation of floc particles,
  allows longer filter runs, settling velocity of
  the floc allows particle removal before the water
  leaves the basin

11
Drinking Water Filtration

• Rapid Sand Filters are most commonly used for
  surface water
• May be gravity or pressure flow
• Some States prohibit pressure flow
• Fine-to-course (back wash result)
• Course-to-fine (multi-media)
• Anthracite, Sand, Course Garnet, Fine Garnet
• Rapid Sand filters may clean 1 - 2 gpm/ft2
• Alternatives include microscreens, diatomaceous
  earth filters, cartridge filters

12
DISINFECTION

• CT concept is the current basis for disinfection
  theory
• CT K
• C disinfectant concentration
• T contact time
• K proportionality constant, variable with
  different organisms
• Ohio regulation 30 min contact time, 0.2 mg/l
  Cl2 residual
• Chlorination is most common in the U.S.
• Effective, low cost, proven technology
• Reactions with natural aquatic organics produce
  trihalomethanes -- suspected carcinogens
• Ozonation is popular in France, Germany, Canada,
  and Russia
• Chlorine Dioxide gaining acceptance in Europe and
  U.S.

13
Chlorine Chemistry

• Cl2 H2O -----gt H Cl- HOCl
• HOCl Hypochlorous Acid, is the most active
  ingredient, concentration is pH dependent
  dissociates to H -OCl
• Active against (listed in decreasing order)
• Bacteria Viruses Protozoans (cysts)
• Chlorine reacts with Ammonia (NH3) to produce
  mono, di, and trichloroamines
• NH2Cl NHCl2 NCl3

14
Chlorine Residuals Chlorine Demand

• Free Chlorine Cl2, HOCl, -OCl
• Combined Chlorine Chloramines
• Free Chlorine has strong disinfecting powers but
  is quickly dissipated
• Combined Chlorine is slower acting but remains in
  solution longer and provides longer-term
  protection
• Chlorine Demand the difference between the
  amount of chlorine applied and the amount of
  free, combined, or total chlorine remaining at
  the end of the contact period
• Anything oxidizable can produce a chlorine
  demand, including pathogens, organics,
  particulates, sulfides, ammonia, etc.

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Alternative Disinfectants

• Ozone
• O3, powerful oxidant, alternative to chlorine
• Effective at low doses
• Expensive (capital and operating costs)
• Produces no residual
• Chlorine Dioxide
• ClO2, an unstable gas, produced at the point of
  use from sodium chlorite, NaClO2
• Nearly as effective as chlorine, does not react
  with ammonia to produce chloramines, or with
  other organics to form trihalomethanes

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BIOFILMS

• In many environments, microorganisms form, and
  exist in, complex, protective layers called
  biofilms
• Biofilms may form in any part of a drinking water
  distribution system. Cooling towers can support
  robust biofilms.
• Disinfectants may be unable to attack or
  completely remove the organisms in biofilms
• Most biofilms are made up of non-pathogenic
  organisms however, pathogens may be protected in
  such an environment

17
Softening

• Reduction in dissolved calcium and magnesium
  reduces deposits in distribution system - scale
  formation (CaCO3)
• Hard water reacts with soap to form films that
  are difficult to remove
• Hard water deposits form scale in boilers
• Softening also removes some trace inorganics
  Pb, Cd, Ag, Ba, Cr, As, Hg, and Ra
• Lime-soda process adds quick lime (CaO) or
  hydrated lime Ca(OH)2, precipitating calcium
  carbonate (CaCO3)
• Ion-exchange removes Ca2 and Mg2 and replaces
  them with Na ions often used in homes

18
Taste Odor Control

• Very low concentrations of metals, salts, or
  organics may produce detectable levels in
  sensitive people - iron, copper, manganese, and
  zinc, magnesium chloride and bicarbonate,
  chlorinated organics fungal and algal
  metabolites hydrogen sulfide, other sulfur
  compounds
• Activated carbon is often very effective in
  removing organics
• Oxidation (chlorine, chlorine dioxide, ozone)

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• Iron Manganese Removal
• Iron and manganese cause staining and leave
  noticeable residuals at very low concentrations
• Fe gt0.2 mg/l Mn gt0.1 mg/l
• Iron promotes growth of iron bacteria in mains
  that increase friction and power consumption
• Oxidation produces less soluble compounds and
  precipitation is often used for removal
• Trace Metals
• Iron, Cadmium, Lead, Copper, Zinc may come from
  the plumbing system others may be from the
  aquifer
• Corrosion control processes may be the most
  effective means of reducing these concentrations
  - precipitation of a layer of calcium carbonate
  often provides a nonreactive surface

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• Turbidity
• A measure of suspended particulates in water -
  clays, microorganisms, organics
• Highly turbid waters are difficult to disinfect
  because of high demands - large amounts of
  materials to be oxidized organisms protected
  from exposure to disinfectants
• Coagulation and flocculation, and filtration are
  common removal methods
• Trace Organics
• Solvents, hydrocarbons, etc. may come from the
  aquifer
• Modified organics may be the result of
  disinfection processes
• Humic and fulvic acids are poorly defined and are
  common in natural waters
• TOC and TOX are broad tests of water quality
• Precipitation, filtration, adsorption, and
  oxidation may all remove some of the materials

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Fluoridation

• The fluoridation process was very controversial
  when initially implemented
• Low concentrations (1 - 2 mg/l) of fluoride
  provide strong protection against tooth decay
• Slightly higher concentrations (gt 4 mg/l) can
  cause discoloring of teeth

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• CROSS CONNECTIONS
• Accidental contamination of drinking water can
  occur during routine plumbing modification, sewer
  backups, floods, earthquakes, careless
  homeowners, etc.
• FOAMING AGENTS
• Surfactants (the active part of detergents) can
  get into surface water through incomplete sewage
  treatment
• Groundwater sources include septic tank systems

23
Nitrate Nitrite

• Nitrate is common in natural waters at 1 to 2
  mg/l
• Nitrate (NO3) is reduced to nitrite (NO2) in the
  digestive system - reduction is more complete in
  infants than adults - because of more alkaline
  conditions in system
• Excess nitrite produces methemoglobinemia in
  infants by oxidizing hemoglobin to methemoglobin
  which cannot carry oxygen
• Nitrosamines formation (suspected carcinogens)
  can also occur from nitrate or nitrite

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• TOTAL DISSOLVED SOLIDS
• High TDS may increase corrosivity because of
  increase conductance
• High sodium may be of health concern
• CORROSIVITY
• Decreases life of plumbing system
• Solubilized metals, perhaps in toxic quantities -
  lead and cadmium are of most concern
• Copper, iron, and zinc produce tastes and stains
• Corrosion can shield microorganisms from
  disinfection processes
• Water may be characterized as passive or
  aggressive

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CLEAN WATER ACT - Background

• Rivers and Harbors Act of 1899
• Prohibited discharge of refuse without a permit
  from the Secretary of the Army
• Water Pollution Control Act of 1948
• Gave primary responsibilities to the States
• Provided construction funds, Money never
  appropriated
• Water Pollution Control Act Amendments of 1956
• Authorized Grants for construction
• Provided funds for research into Health Effects
• Other minor Acts in 1961, 1965, 1966, 1970

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• Federal Water Pollution Control Act - 1972 - PL
  92-500
• Goal of fishable/swimmable water
• Construction Grants for Sewage Treatment
  Facilities
• BPT - Best Practicable Treatment
• BAT - Best Available Treatment
• Concentrated on Oxygen Demand, Suspended Solids
• 1976 - NRDC v. Train - Consent Decree - resulted
  in...
• Clean Water Act - 1977 - PL 95-217
• Wetlands Resources Act - 1986
• Water Quality Act Amendments of 1987
• Required EPA regulations on storm water runoff
• Required State nonpoint source management programs

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TITLE I -RESEARCH AND RELATED PROGRAMS

• Sec. 101 - Declaration of Goals and Policy --
  Objective Restore and maintain the chemical,
  physical, and biological integrity of the
  Nation's waters.
• Goals
• 1. Eliminate pollutant discharges into navigable
  waters by 1985.
• 2. Interim goal to protect fish, shellfish, and
  wildlife and provide for recreation in and on the
  water by July 1, 1983.
• 3. Prohibit the discharge of toxic pollutants in
  toxic amounts.

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TITLE III - STANDARDS AND ENFORCEMENT

• 304 - Information and Guidelines - provides for
  development of water quality criteria. Defines
  conventional pollutants - including, but not
  limited to, biological oxygen demand, suspended
  solids, fecal coliforms, and pH, --- specifically
  excluded thermal.
• 305 - Water Quality Inventory - requires States
  to provide a water quality description, an
  inventory of point-source dischargers, and an
  estimate of costs of improving quality.
• 306 - National Standards of Performance -
  requires a list of categories of sources and
  establishment of new source performance standards
  for those categories

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TITLE IV PERMITS AND LICENSES

• Sec 402 - National Pollutant Discharge
  Elimination System - (NPDES) establishes
  requirements for issuing permits and State
  implementation of the program.
• Excludes Irrigation return flows, Storm water
  runoff from Oil, Gas and Mining operations
• Anti-Backsliding - renewed permits must be as
  stringent as the original
• Storm water is included by October 1, 1993

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ADDITIONS, AMENDMENTS

• LIMITATIONS ON DISCHARGE OF RAW SEWAGE BY NEW
  YORK CITY
• North River Plant - required to have advanced
  preliminary treatment by Aug, 1986
• Red Hook Plant - required advanced preliminary
  treatment by Aug, 1987
• BOSTON HARBOR AND ADJACENT WATERS
• Authorization for constructing waste treatment
  works for providing secondary treatment

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Oil Pollution Act

• Revised penalties for oil discharges
• Administrative penalties of 125,000 for
  violations of regulations or discharges
• Civil penalties of 25,000/ day for discharges,
  or 1,000/ barrel of oil
• Gross negligence or misconduct minimum penalty of
  100,000

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CONVENTIONAL POLLUTANTS

• Several are Empirical, derived by
  experimentation
• Biological Oxygen Demand - test using
  microorganisms that measures oxygen uptake over
  five days
• Suspended Solids - quantified by filtration of a
  sample and drying and weighing the filter
• Fecal Coliform Bacteria - microbial analysis
  dependent upon incubation conditions and
  selective media
• pH - measured directly
• Oil and Grease - derived by extraction of a water
  sample with a solvent and either an infra-red
  (IR) measure of the solvent, or a gravimetric
  measure of the residue

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Pretreatment Regulations

• Industrial discharges into POTWs (40 CFR 403)
• POTWs with flows gt 5 million gpd, or smaller
  POTWs with significant industrial discharges must
  establish local pretreatment programs
• National standards must be enforced
• Hazardous wastes are the focus of regulation
• Significant industrial users must meet reporting
  requirements
• Users subject to categorical pretreatment
  standards
• Users of gt 25,000 gpd of processed wastewater
• Users that make up gt5 average organic capacity
• Other users with a reasonable potential to
  adversely effect the POTWs operation

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Wastewater Treatment

• Collection System
• Sewage
• Domestic (sanitary)
• Industrial
• Mixed
• Stormwater
• Separate Systems
• Combined Systems
• Infiltration (20 to 3,000 gal/acre/day)

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Unit Operations Unit Processes

• Unit Operations - Treatment methods using
  physical forces
• Screening Mixing Flocculation
• Sedimentation Flotation Filtration
• Aeration (gas transfer)
• Unit Processes - Treatment methods using chemical
  or biological reactions
• Precipitation Adsorption Disinfection
• Biodegradation Nutrient Removal

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Treatment Levels

• Primary Treatment - (preliminary), physical unit
  operations
• Removal of constituents that cause maintenance or
  operational problems -- debris, grit, oil and
  grease,
• Secondary Treatment - chemical and biological
  unit processes
• Removal of biodegradable organics and suspended
  solids
• Tertiary Treatment - (advanced), combinations of
  all three methods
• Removal of residual nutrients, toxics, specific
  contaminants

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Typical Treatment Process

• Bar Grit
• Influent Screen Chamber Primary
• Clarifier
• Anaerobic Activated
• Digester Sludge Unit(s)
• Disinfection Secondary
• Clarifier
• Effluent

Sludge Disposal
Sludge Return
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Industrial WastewaterTreatment - Differences

• Equalization - hydraulic residence time at least
  equal to activated sludge unit, may be several
  times longer
• Oil Separation
• Dissolved Air Flotation, Dissolved Gas Flotation
• Corrugated Plate Interceptors
• Sludges may be hazardous by regulation

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Design Criteria

• Flow Rate
• Peak Hour Maximum Day
• Maximum Month Minimum Hour
• Minimum Day Minimum Month
• Mass Loading
• Maximum Day Sustained Peaks
• Maximum Month Minimum Month
• Minimum Day

40
WastewaterDaily Flow Pattern

• Midnight Noon Midnight

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Reactor Types

• Homogeneous Reactions
• Batch Reactor
• Plug-Flow Reactor
• Complete-Mix Reactor, Stirred Tank Reactor
• Complete-Mix Reactors in Series -
• May be significantly more effective than the same
  volume in a single unit
• Arbitrary -Flow Reactor
• Heterogeneous Reactions
• Packed-Bed Reactor
• Fluidized-Bed Reactor

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Mass-Balance Analysis

• Accumulation Inflow - Outflow Generation
• V dC/dt QCo - QC V(-kC)
• V volume of reactor
• dC/dt rate of change of reactant concentration
  within reactor
• Q volumetric flow rate into/out of reactor
• Co reactant concentration in influent
• C reactant concentration in reactor and
  effluent
• k first-order reaction-rate constant
• Mass Balance Applications
• Model constituent biodegradation or removal
  (volatilization, precipitation, etc.)
• Model solids (sludge) formation

43
Common Operational and Design Practices

• Gravity flow through system
• Only pump the water one time
• Parallel units
• Allow operational flexibility and maintenance
• Minimize human contact with materials

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SIMPLIFIED TREATMENT FLOWFairborn Plant

• Raw
• Sewage

Grit Tanks
Oxidation Ditches
Digesters
Landfill
Sludge Return
Disinfection
Clarifiers
Effluent to Mad River
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Fairborn NPDES Permit Requirements

• Sampling Stations
• Plant Outfall
• Waste Sludge
• Raw Sewage Influent
• Upstream at State Route 235
• Downstream - 200 ft south of lift station at
  River Mile 8.6
• Samples
• Composite samples of at least three grab samples
  proportionate in volume to the sewage flow rate
  at the time of sampling...intervals of at least
  30 min., but not more than 2 hours

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FairbornPerformance Statistics

• Average Daily Flow (mgd) 3.795
• Average Influent
• Suspended Solids 198 mg/l
• BOD 143 mg/l
• Ammonia 16 mg/l
• Average Effluent
• Suspended Solids 6 mg/l 97
• BOD 3 mg/l 98
• Ammonia 0.1 mg/l 99