United States
`Environmental Protection
`Agency
`
`Office of Water
`Office of Wastewater Management
`Washington DC 20460
`
`EPA 832-R-04-001
`September 2004
`
`Primer for Municipal
`Wastewater Treatment
`Systems
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 1 of 30
`
`

`

`Primer for Municipal Wastewater Treatment Systems
`
`Clean Water Act Requirements for Wastewater Treatment
`
`The Need for Wastewater Treatment
`
`Effects of Wastewater on Water Quality
`
`Some of the Key Challenges Faced by Wastewater Treatment Professionals Today
`
`Collecting and Treating Wastewater
`
`Centralized Collection
`
` Combined Sewer Systems
`
`
`Sanitary Sewer System
`Pollutants:
` Oxygen-Demanding Substances
`
`Pathogens
` Nutrients
`
`Synthetic Organic and Inorganic Chemicals
`
`Thermal
`
`Wastewater Treatment
`
`Primary Treatment
`
`
`Preliminary Treatment
`
`
`Primary Sedimentation
`
`Basic Wastewater Treatment Processes
`
`
`Physical
`
` Biological
`
` Chemical
`
`Secondary Treatment
`
` Attached Growth Processes
`
`
`Suspended Growth Processes
`
`
`Lagoons
`
`Land Treatment
`
`
`Slow Rate Infiltration
`
` Rapid Infiltration
`
` Overland Flow
`
`Constructed Wetlands
` Disinfection
`
` Chlorine
`
` Ozone
`
` Ultraviolet Radiation
`
`Pretreatment
`
`Advanced Methods of Wastewater Treatment
` Nitrogen Control
`
`Biological Phosphorus Control
`
`Coagulation-Sedimentation
`
`Carbon Adsorption
`
`The Use or Disposal of Wastewater Residuals and Biosolids
`
`Land Application
`
`Incineration
`
`Beneficial Use Products from Biosolids
`
`Decentralized (Onsite or Cluster) Systems
`
`Treatment
`
` Conventional Septic Tanks
` Aerobic Treatment Units
`
` Media Filters
` Dispersal Approaches
`
` Absorption Field
`
` Mound System
`
` Drip Dispersal System
`
`
`Evapotranspiration Beds
` Management of Onsite/Decentralized Wastewater Systems
`
`Asset Management
` Operation
` Maintenance
`
`Common Wastewater Treatment Terminology
`
`4
`
`5
`
`5
`
`6
`
`6
`6
`7
`9
`8
`8
`8
`8
`8
`8
`
`9
`9
`9
`11
`10
`10
`10
`10
`11
`11
`12
`13
`14
`14
`15
`15
`15
`16
`16
`16
`16
`
`16
`
`17
`17
`18
`18
`19
`
`19
`20
`20
`21
`
`21
`22
`22
`22
`22
`23
`23
`23
`24
`24
`24
`
`24
`25
`25
`
`25
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 2 of 30
`
`

`

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`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 3 of 30
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 3 of 30
`
`

`

` Clean Water Act Requirements for
`Wastewater Treatment
`
`The 1972 Amendments to the Federal
`Water Pollution Control Act (Public Law 92-
`500–, known as the Clean Water Act (CWA),
`established the foundation for wastewater
`discharge control in this country. The CWA’s
`primary objective is to ‘restore and maintain the
`chemical, physical and biological integrity of the
`nation’s waters.’
`
`The CWA established a control program for
`ensuring that communities have clean water
`by regulating the release of contaminants
`into our country’s waterways. Permits that
`limit the amount of pollutants discharged
`are required of all municipal and industrial
`wastewater dischargers under the National
`Pollutant Discharge Elimination System (NPDES)
`permit program. In addition, a construction
`grants program was set up to assist publicly-
`owned wastewater treatment works build the
`improvements required to meet these new limits.
`The 1987 Amendments to the CWA established
`State Revolving Funds (SRF) to replace grants as
`the current principal federal funding source for
`the construction of wastewater treatment and
`collection systems.
`
`Over 75 percent of the nation’s population is
`served by centralized wastewater collection
`and treatment systems. The remaining
`population uses septic or other onsite systems.
`Approximately 16,000 municipal wastewater
`treatment facilities are in operation nationwide.
`The CWA requires that municipal wastewater
`treatment plant discharges meet a minimum of
`‘secondary treatment’. Over 30 percent of the
`wastewater treatment facilities today produce
`cleaner discharges by providing even greater
`levels of treatment than secondary.
`
`4
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 4 of 30
`
`

`

`Primer for Municipal
`Wastewater Treatment
`Systems
`
`produced can greatly alter
`the amount and complexity
`of industrial wastes and
`challenge traditional
`treatment technology. The
`application of commercial
`fertilizers and pesticides,
`combined with sediment
`from growing development
`activities, continues to be a
`source of significant pollution
`as runoff washes off the
`land.
`Water pollution issues now
`dominate public concerns
`about national water quality
`and maintaining healthy
`ecosystems. Although a
`large investment in water
`pollution control has helped
`reduce the problem, many
`miles of streams are still
`impacted by a variety of
`different pollutants. This,
`in turn, affects the ability of
`
`people to use the water for
`beneficial purposes. Past
`approaches used to control
`water pollution control must
`be modified to accommodate
`current and emerging issues
`
`Effects of Wastewater on
`Water Quality
`The basic function of the
`wastewater treatment plant
`is to speed up the natural
`processes by which water
`purifies itself. In earlier
`years, the natural treatment
`process in streams and
`lakes was adequate to
`perform basic wastewater
`treatment. As our population
`and industry grew to their
`present size, increased
`levels of treatment prior
`to discharging domestic
`wastewater became
`necessary.
`
`The Need for Wastewa-
`ter Treatment
`Wastewater treatment is
`needed so that we can
`use our rivers and streams
`for fishing, swimming and
`drinking water. For the first
`half of the 20th century,
`pollution in the Nation’s
`urban waterways resulted in
`frequent occurrences of low
`dissolved oxygen, fish kills,
`algal blooms and bacterial
`contamination. Early efforts
`in water pollution control
`prevented human waste
`from reaching water supplies
`or reduced floating debris
`that obstructed shipping.
`Pollution problems and their
`control were primarily local,
`not national, concerns.
`Since then, population
`and industrial growth have
`increased demands on our
`natural resources, altering
`the situation dramatically.
`Progress in abating pollution
`has barely kept ahead of
`population growth, changes
`in industrial processes,
`technological developments,
`changes in land use,
`business innovations,
`and many other factors.
`Increases in both the
`quantity and variety of goods
`
`5
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 5 of 30
`
`

`

`Collecting and Treating
`Wastewater
`The most common form
`of pollution control in the
`United States consists of
`a system of sewers and
`wastewater treatment plants.
`The sewers collect municipal
`wastewater from homes,
`businesses, and industries
`and deliver it to facilities
`for treatment before it is
`discharged to water bodies
`or land, or reused.
`
`Centralized Collection
`During the early days of our
`nation’s history, people living
`in both the cities and the
`countryside used cesspools
`and privies to dispose of
`domestic wastewater. Cities
`began to install wastewater
`collection systems in the late
`nineteenth century because
`of an increasing awareness
`of waterborne disease and
`the popularity of indoor
`plumbing and flush toilets.
`The use of sewage collection
`systems brought dramatic
`improvements to public
`health, further encouraging
`the growth of metropolitan
`areas. In the year 2000
`approximately 208 million
`people in the U.S. were
`served by centralized
`collection systems.
`
`(Data form U.S. Public Health Service multi wastewater inventories:
`2000 USEPA Clean Watershed Needs Survey)
`
`Population Receiving Different Levels of
`Wastewater Treatment
`
`2
` No Discharge
` Greater than
` Secondary
` Secondary
` Less than
` Secondary
`1
` Raw Discharge
`
`220
`
`200
`180
`160
`
`140
`
`120
`
`100
`
`80
`
`60
`
`40
`
`20
`
`0
`
`Population Served (millions)
`
`Before the CWA
`
`After the CWA
`
`1 Raw discharges were eliminated by 1996
`2 Data for the "no-discharge" category were unavailable for 1968
`
`Some of the key challenges faced by wastewater
`treatment professionals today:
`
` Many of the wastewater treatment and collection facilities
`are now old and worn, and require further improvement,
`repair or replacement to maintain their useful life;
`
` The character and quantity of contaminants presenting
`problems today are far more complex than those that pre-
`sented challenges in the past;
`
` Population growth is taxing many existing wastewater
`treatment systems and creating a need for new plants;
`
` Farm runoff and increasing urbanization provide ad-
`ditional sources of pollution not controlled by wastewater
`treatment; and
`
` One third of new development is served by decentralized
`systems (e.g., septic systems) as population migrates further
`from metropolitan areas.
`
`6
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 6 of 30
`
`

`

`Combined Sewer Systems
`Many of the earliest sewer systems were combined sewers, designed to collect both sanitary
`wastewater and storm water runoff in a single system. These combined sewer systems were
`designed to provide storm drainage from streets and roofs to prevent flooding in cities.
`Later, lines were added to carry domestic wastewater away from homes and businesses.
`Early sanitarians thought that these combined systems provided adequate health protection.
`We now know that the overflows designed to release excess flow during rains also release
`pathogens and other pollutants.
`Simplified Urban Water Cycle
`
`7
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 7 of 30
`
`

`

`Pollutants
`Oxygen-Demanding Substances
`
`Dissolved oxygen is a key element in water quality that is necessary to support aquatic life.
`A demand is placed on the natural supply of dissolved oxygen by many pollutants in waste-
`water. This is called biochemical oxygen demand, or BOD, and is used to measure how well
`a sewage treatment plant is working. If the effluent, the treated wastewater produced by a
`treatment plant, has a high content of organic pollutants or ammonia, it will demand more
`oxygen from the water and leave the water with less oxygen to support fish and other aquatic
`life.
`Organic matter and ammonia are “oxygen-demanding” substances. Oxygen-demand-
`ing substances are contributed by domestic sewage and agricultural and industrial wastes
`of both plant and animal origin, such as those from food processing, paper mills, tanning,
`and other manufacturing processes. These substances are usually destroyed or converted
`to other compounds by bacteria if there is sufficient oxygen present in the water, but the dis-
`solved oxygen needed to sustain fish life is used up in this break down process.
`
`Pathogens
`
`Disinfection of wastewater and chlorination of drinking water supplies has reduced the oc-
`currence of waterborne diseases such as typhoid fever, cholera, and dysentery, which remain
`problems in underdeveloped countries while they have been virtually eliminated in the U.S.
`Infectious micro-organisms, or pathogens, may be carried into surface and groundwater by
`sewage from cities and institutions, by certain kinds of industrial wastes, such as tanning and
`meat packing plants, and by the contamination of storm runoff with animal wastes from pets,
`livestock and wild animals, such as geese or deer. Humans may come in contact with these
`pathogens either by drinking contaminated water or through swimming, fishing, or other
`contact activities. Modern disinfection techniques have greatly reduced the danger of water-
`borne disease.
`
`Nutrients
`
`Carbon, nitrogen, and phosphorus are essential to living organisms and are the chief nutri-
`ents present in natural water. Large amounts of these nutrients are also present in sewage,
`certain industrial wastes, and drainage from fertilized land. Conventional secondary bio-
`logical treatment processes do not remove the phosphorus and nitrogen to any substantial
`extent -- in fact, they may convert the organic forms of these substances into mineral form,
`making them more usable by plant life. When an excess of these nutrients overstimulates the
`growth of water plants, the result causes unsightly conditions, interferes with drinking water
`treatment processes, and causes unpleasant and disagreeable tastes and odors in drinking
`water. The release of large amounts of nutrients, primarily phosphorus but occasionally ni-
`trogen, causes nutrient enrichment which results in excessive growth of algae. Uncontrolled
`algae growth blocks out sunlight and chokes aquatic plants and animals by depleting dis-
`solved oxygen in the water at night. The release of nutrients in quantities that exceed the
`affected waterbody’s ability to assimilate them results in a condition called eutrophication or
`cultural enrichment.
`
`Inorganic and Synthetic Organic Chemicals
`
`A vast array of chemicals are included in this category. Examples include detergents, house-
`hold cleaning aids, heavy metals, pharmaceuticals, synthetic organic pesticides and her-
`bicides, industrial chemicals, and the wastes from their manufacture. Many of these sub-
`stances are toxic to fish and aquatic life and many are harmful to humans. Some are known
`to be highly poisonous at very low concentrations. Others can cause taste and odor prob-
`lems, and many are not effectively removed by conventional wastewater treatment.
`
`Thermal
`
`Heat reduces the capacity of water to retain oxygen. In some areas, water used for cooling
`is discharged to streams at elevated temperatures from power plants and industries. Even
`discharges from wastewater treatment plants and storm water retention ponds affected by
`summer heat can be released at temperatures above that of the receiving water, and elevate
`the stream temperature. Unchecked discharges of waste heat can seriously alter the ecology
`of a lake, a stream, or estuary.
`
`8
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 8 of 30
`
`

`

`Wastewater Treatment
`In 1892, only 27 American
`cities provided wastewater
`treatment. Today, more
`than 16,000 publicly-owned
`wastewater treatment plants
`operate in the United States
`and its territories. The
`construction of wastewater
`treatment facilities
`blossomed in the 1920s and
`again after the passage of
`the CWA in 1972 with the
`availability of grant funding
`and new requirements
`calling for minimum levels
`of treatment. Adequate
`treatment of wastewater,
`along with the ability to
`provide a sufficient supply
`of clean water, has become
`a major concern for many
`communities.
`
`Primary Treatment
`The initial stage in the
`treatment of domestic
`wastewater is known as
`primary treatment. Coarse
`solids are removed from
`the wastewater in the
`primary stage of treatment.
`In some treatment plants,
`primary and secondary
`stages may be combined
`into one basic operation.
`At many wastewater
`treatment facilities, influent
`passes through preliminary
`treatment units before
`primary and secondary
`treatment begins.
`
`Preliminary Treatment
`As wastewater enters a
`treatment facility, it typically
`flows through a step called
`preliminary treatment. A
`screen removes large floating
`objects, such as rags, cans,
`bottles and sticks that may
`clog pumps, small pipes, and
`down stream processes. The
`screens vary from coarse to
`fine and are constructed with
`parallel steel or iron bars
`with openings of about half
`an inch, while others may
`be made from mesh screens
`with much smaller openings.
`
`Screens are generally placed
`in a chamber or channel and
`inclined towards the flow of
`the wastewater. The inclined
`screen allows debris to be
`caught on the upstream
`surface of the screen, and
`allows access for manual
`or mechanical cleaning.
`Some plants use devices
`known as comminutors or
`barminutors which combine
`the functions of a screen and
`a grinder. These devices
`catch and then cut or shred
`the heavy solid and floating
`material. In the process, the
`pulverized matter remains
`in the wastewater flow to be
`removed later in a primary
`settling tank.
`
`Workers install sewer line
`Sanitary Sewer Systems
`Sanitary sewer collection
`systems serve over half the
`people in the United States
`today. EPA estimates that
`there are approximately
`500,000 miles of publicly-
`owned sanitary sewers
`with a similar expanse of
`privately-owned sewer
`systems. Sanitary sewers
`were designed and built
`to carry wastewater from
`domestic, industrial and
`commercial sources, but
`not to carry storm water.
`Nonetheless, some storm
`water enters sanitary sewers
`through cracks, particularly
`in older lines, and through
`roof and basement drains.
`Due to the much smaller
`volumes of wastewater
`that pass through sanitary
`sewer lines compared to
`combined sewers, sanitary
`sewer systems use smaller
`pipes and lower the cost of
`collecting wastewater.
`
`“the ability to
`
`provide a sufficient
`
`supply of clean
`
`water continues to
`
`be a major national
`
`concern”
`
`9
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 9 of 30
`
`

`

`Basic Wastewater Treatment Processes
`Physical
`Biological
`Physical processes were
`In nature, bacteria and
`some of the earliest methods
`other small organisms in
`to remove solids from
`water consume organic
`wastewater, usually by
`matter in sewage, turning
`passing wastewater through
`it into new bacterial cells,
`screens to remove debris
`carbon dioxide, and other
`and solids. In addition,
`by-products. The bacteria
`solids that are heavier than
`normally present in water
`water will settle out from
`must have oxygen to do
`wastewater by gravity.
`their part in breaking down
`Particles with entrapped
`the sewage. In the 1920s,
`air float to the top of water
`scientists observed that these
`and can also be removed.
`natural processes could be
`These physical processes are
`contained and accelerated
`employed in many modern
`in systems to remove organic
`wastewater treatment
`material from wastewater.
`facilities today.
`With the addition of oxygen
`to wastewater, masses of
`microorganisms grew and
`rapidly metabolized organic
`pollutants. Any excess
`microbiological growth
`could be removed from
`the wastewater by physical
`processes.
`
`Chemical
`Chemicals can be used to
`create changes in pollutants
`that increase the removal
`of these new forms by
`physical processes. Simple
`chemicals such as alum,
`lime or iron salts can be
`added to wastewater to
`cause certain pollutants,
`such as phosphorus, to floc
`or bunch together into large,
`heavier masses which can
`be removed faster through
`physical processes. Over the
`past 30 years, the chemical
`industry has developed
`synthetic inert chemicals
`know as polymers to
`further improve the physical
`separation step in wastewater
`treatment. Polymers are
`often used at the later
`stages of treatment to
`improve the settling of excess
`microbiological growth or
`biosolids.
`
`After the wastewater has
`been screened, it may flow
`into a grit chamber where
`sand, grit, cinders, and small
`stones settle to the bottom.
`Removing the grit and gravel
`that washes off streets or
`land during storms is very
`important, especially in
`cities with combined sewer
`systems. Large amounts
`
`of grit and sand entering a
`treatment plant can cause
`serious operating problems,
`such as excessive wear of
`pumps and other equipment,
`clogging of aeration devices,
`or taking up capacity in tanks
`that is needed for treatment.
`In some plants, another
`finer screen is placed after
`the grit chamber to remove
`
`any additional material that
`might damage equipment or
`interfere with later processes.
`The grit and screenings
`removed by these processes
`must be periodically
`collected and trucked to a
`landfill for disposal or are
`incinerated.
`.
`
`10
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 10 of 30
`
`

`

`Primary Sedimentation
`With the screening
`completed and the grit
`removed, wastewater still
`contains dissolved organic
`and inorganic constituents
`along with suspended
`solids. The suspended solids
`consist of minute particles of
`matter that can be removed
`from the wastewater
`with further treatment
`such as sedimentation or
`gravity settling, chemical
`coagulation, or filtration.
`Pollutants that are dissolved
`or are very fine and remain
`suspended in the wastewater
`are not removed effectively
`by gravity settling.
`
`When the wastewater enters
`a sedimentation tank, it slows
`down and the suspended
`solids gradually sink to the
`bottom. This mass of solids
`is called primary sludge.
`Various methods have been
`devised to remove primary
`sludge from the tanks.
`Newer plants have some type
`of mechanical equipment
`to remove the settled solids
`from sedimentation tanks.
`Some plants remove solids
`continuously while others do
`so at intervals.
`
`secondary treatment are
`attached growth processes
`and suspended growth
`processes..
`
`Attached Growth
`Processes
`In attached growth (or fixed
`film) processes, the microbial
`growth occurs on the surface
`of stone or plastic media.
`Wastewater passes over
`the media along with air to
`
`Solids removed from
`automated bar screens
`
`Secondary Treatment
`After the wastewater has
`been through Primary
`Treatment processes, it
`flows into the next stage of
`treatment called secondary.
`Secondary treatment
`processes can remove up to
`90 percent of the organic
`matter in wastewater by
`using biological treatment
`processes. The two most
`common conventional
`methods used to achieve
`
`Aerated Grit Chamber
`
`11
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 11 of 30
`
`

`

`Sequencing Batch
`Reactor
`
`media bed material. New
`facilities may use beds made
`of plastic balls, interlocking
`sheets of corrugated plastic,
`or other types of synthetic
`media. This type of bed
`material often provides
`more surface area and
`a better environment for
`promoting and controlling
`biological treatment than
`rock. Bacteria, algae, fungi
`and other microorganisms
`grow and multiply, forming
`a microbial growth or slime
`layer (biomass) on the
`media. In the treatment
`process, the bacteria use
`oxygen from the air and
`consume most of the organic
`matter in the wastewater as
`food. As the wastewater
`passes down through the
`media, oxygen-demanding
`substances are consumed by
`the biomass and the water
`leaving the media is much
`cleaner. However, portions
`of the biomass also slough
`off the media and must settle
`out in a secondary treatment
`tank.
`
`provide oxygen. Attached
`growth process units include
`trickling filters, biotowers,
`and rotating biological
`contactors. Attached growth
`processes are effective at
`removing biodegradable
`organic material from the
`wastewater.
`
`A trickling filter is simply
`a bed of media (typically
`rocks or plastic) through
`which the wastewater passes.
`The media ranges from
`three to six feet deep and
`allows large numbers of
`microorganisms to attach
`and grow. Older treatment
`facilities typically used
`stones, rocks, or slag as the
`
`Trickling Filters
`
`12
`
`Suspended Growth
`Processes
`Similar to the microbial
`processes in attached growth
`systems, suspended growth
`processes are designed
`to remove biodegradable
`organic material and
`organic nitrogen-containing
`material by converting
`ammonia nitrogen to
`nitrate unless additional
`treatment is provided. In
`suspended growth processes,
`the microbial growth is
`suspended in an aerated
`water mixture where the air
`is pumped in, or the water is
`agitated sufficiently to allow
`oxygen transfer. Suspended
`growth process units include
`variations of activated
`sludge, oxidation ditches and
`sequencing batch reactors.
`
`The suspended growth
`process speeds up the work
`of aerobic bacteria and
`other microorganisms that
`break down the organic
`matter in the sewage by
`providing a rich aerobic
`environment where the
`microorganisms suspended
`in the wastewater can work
`more efficiently. In the
`aeration tank, wastewater is
`vigorously mixed with air and
`microorganisms acclimated
`to the wastewater in a
`suspension for several hours.
`This allows the bacteria
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 12 of 30
`
`

`

`Brush Aerators in an Oxidation Ditch
`
`and other microorganisms
`to break down the organic
`matter in the wastewater.
`The microorganisms grow
`in number and the excess
`biomass is removed by
`settling before the effluent
`is discharged or treated
`further. Now activated
`with millions of additional
`aerobic bacteria, some of
`the biomass can be used
`again by returning it to an
`aeration tank for mixing with
`incoming wastewater.
`
`The activated sludge
`process, like most other
`techniques, has advantages
`and limitations. The units
`necessary for this treatment
`are relatively small, requiring
`less space than attached
`growth processes. In
`addition, when properly
`operated and maintained,
`the process is generally
`free of flies and odors.
`However, most activated
`sludge processes are more
`costly to operate than
`attached growth processes
`due to higher energy use
`
`to run the aeration system.
`The effectiveness of the
`activated sludge process
`can be impacted by elevated
`levels of toxic compounds in
`wastewater unless complex
`industrial chemicals are
`effectively controlled through
`an industrial pretreatment
`program.
`
`An adequate supply of
`oxygen is necessary for the
`activated sludge process to
`be effective. The oxygen
`is generally supplied by
`mixing air with the sewage
`and biologically active
`solids in the aeration
`tanks by one or more of
`several different methods.
`Mechanical aeration can be
`accomplished by drawing
`the sewage up from the
`bottom of the tank and
`spraying it over the surface,
`thus allowing the sewage
`to absorb large amounts of
`oxygen from the atmosphere.
`Pressurized air can be forced
`out through small openings
`in pipes suspended in the
`wastewater. Combination
`
`Centerfeed well of a clarifier for
`removing excess biomass
`
`of mechanical aeration and
`forced aeration can also be
`used. Also, relatively pure
`oxygen, produced by several
`different manufacturing
`processes, can be added
`to provide oxygen to the
`aeration tanks.
`
`From the aeration tank,
`the treated wastewater
`flows to a sedimentation
`tank (secondary clarifier),
`where the excess biomass
`is removed. Some of the
`biomass is recycled to the
`head end of the aeration
`tank, while the remainder is
`“wasted” from the system.
`The waste biomass and
`settled solids are treated
`before disposal or reuse as
`biosolids.
`
`Lagoons
`A wastewater lagoon
`or treatment pond is a
`scientifically constructed
`pond, three to five feet
`deep, that allows sunlight,
`
`13
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 13 of 30
`
`

`

`Wastewater Lagoon
`
`Land Treatment
`Land treatment is the
`controlled application of
`wastewater to the soil where
`physical, chemical, and
`biological processes treat
`the wastewater as it passes
`across or through the soil.
`The principal types of land
`treatment are slow rate,
`overland flow, and rapid
`infiltration. In the arid
`western states, pretreated
`municipal wastewater has
`been used for many years
`to irrigate crops. In more
`recent years, land treatment
`has spread to all sections of
`the country. Land treatment
`of many types of industrial
`wastewater is also common.
`
`Whatever method is
`used, land treatment can
`be a feasible economic
`alternative, where the land
`area needed is readily
`available, particularly
`when compared to costly
`advanced treatment plants.
`Extensive research has been
`conducted at land treatment
`sites to determine treatment
`performance and study
`the numerous treatment
`processes involved, as
`well as potential impacts
`on the environment, e.g.
`groundwater, surface water,
`and any crop that may be
`grown.
`
`
`Slow Rate Infiltration
`In the case of slow rate
`infiltration, the wastewater
`is applied to the land and
`moves through the soil
`where the natural filtering
`action of the soil along
`with microbial activity and
`plant uptake removes most
`contaminants. Part of the
`water evaporates or is used
`by plants. The remainder is
`either collected via drains or
`wells for surface discharge or
`allowed to percolate into the
`groundwater.
`
`Slow rate infiltration is
`the most commonly used
`land treatment technique.
`The wastewater, which is
`sometimes disinfected before
`application, depending on
`the end use of the crop and
`the irrigation method, can
`be applied to the land by
`spraying, flooding, or ridge
`and furrow irrigation. The
`method selected depends on
`cost considerations, terrain,
`and the type of crops. Much
`of the water and most of the
`nutrients are used by the
`plants, while other pollutants
`are transferred to the soil
`by adsorption, where many
`are mineralized or broken
`down over time by microbial
`action.
`
`algae, bacteria, and oxygen
`to interact. Biological and
`physical treatment processes
`occur in the lagoon to
`improve water quality. The
`quality of water leaving the
`lagoon, when constructed
`and operated properly, is
`considered equivalent to the
`effluent from a conventional
`secondary treatment system.
`However, winters in cold
`climates have a significant
`impact on the effectiveness
`of lagoons, and winter
`storage is usually required.
`
`Lagoons have several
`advantages when used
`correctly. They can be used
`for secondary treatment
`or as a supplement to
`other processes. While
`treatment ponds require
`substantial land area and
`are predominantly used
`by smaller communities,
`they account for more
`than one-fourth of the
`municipal wastewater
`treatment facilities in this
`country. Lagoons remove
`biodegradable organic
`material and some of the
`nitrogen from wastewater.
`
`14
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 14 of 30
`
`

`

`Constructed Wetlands
`
`15
`
`Constructed Wetlands
`Wetlands are areas where
`the water saturates the
`ground long enough to
`support and maintain
`wetland vegetation such
`as reeds, bulrush, and
`cattails. A “constructed
`wetlands” treatment system is
`designed to treat wastewater
`by passing it through the
`wetland. Natural physical,
`chemical, and biological
`wetland processes have been
`recreated and enhanced
`in constructed wetlands
`designed specifically to treat
`wastewater from industries,
`small communities, storm
`runoff from urban and
`agricultural areas, and acid
`mine drainage. Significant
`water quality improvements,
`including nutrient reduction,
`can be achieved
`
`Biologically Degradable Wastewater Treated in the U.S. has
`increased since 1940, however, treatment efficiency has
`improved so that pollution has decreased.
`
`
`
`Influent BOD5
`
` Effluent BOD5
`
` Removal Efficiency
`
`BOD5 Removal Efficiency (%)
`
`80,000
`
`70,000
`
`60,000
`
`50,000
`
`40,000
`
`30,000
`
`20,000
`
`10,000
`
`0
`
`BOD5 Loading (metric tons/day)
`
`1940 1950 1960 1970 1980 1990 1996 2016
`
`Year
`
`1 165 gal/capita-day is based on data in the Clean Water Needs Surveys for 1978
`through 1986 and accounts for residential, commercial, industrial, stormwater, and
`infiltration and inflow components.
`
`Rapid Infiltration
`The rapid infiltration
`process is most frequently
`used to polish and recover
`wastewater effluents for
`reuse after pretreatment by
`secondary and advanced
`treatment processes. It is
`also effective in cold or
`wet weather and has been
`successfully used in Florida,
`northeastern and arid
`southwestern states. Large
`amounts of wastewater
`are applied to permeable
`soils in a limited land area
`and allowed to infiltrate
`and percolate downward
`through the soil into the
`water table below. If the
`water is to be reused, it can
`be recovered by wells. The
`cost-effectiveness of this
`process depends on the soil’s
`ability to percolate a large
`volume of water quickly and
`efficiently, so suitable soil
`drainage is important.
`
`Overland Flow
`
`This method has been used
`successfully by the food
`processing industries for
`many years to remove solids,
`bacteria and nutrients from
`wastewater. The wastewater
`is allowed to flow down a
`gently-sloped surface that is
`planted with vegetation to
`control runoff and erosion.
`Heavy clay soils are well
`suited to the overland flow
`process. As the water flows
`down the slope, the soil and
`its microorganisms form a
`gelatinous slime layer similar
`in many ways to a trickling
`filter that effectively removes
`solids, pathogens, and nutri-
`ents. Water that is not
`absorbed or evaporated is
`recovered at the bottom of
`the slope for discharge or
`reuse.
`
`Exhibit 2022
`Bazooka v. Nuhn - IPR2024-00098
`Page 15 of