White Papers


Felisa Cantu

Every day, countless amounts of fats, oils, and grease (“FOG”) are disposed down drains. Overtime when FOG is released into the sewer system, FOG solidifies and undergoes a chemical reaction with the wastewater, forming particles that deposit onto the surface of sewer pipe to a point where wastewater cannot pass through. Additionally, with the recent popularity of “flushable” hygienic wipes, clogs are forming even faster as hardened grease is attaching to non-decomposed wipes flushed down the toilet.


The appeal of “flushable” wipes is that they are easy to dispose of and often labeled as “flushable.” While these wipes may be labeled “flushable,” the Federal Trade Commission ("FTC") has not legally defined the term, nor has the FTC set forth any regulations for a company to claim their wipe products to be “flushable."

Currently, there are only voluntary guidelines and assessment tests that validate properties needed for a wipe to be marketed as “flushable.” In 2018, the International Nonwovens Disposables Association (“INDA”) and the European Disposables and Nonwovens Association (“EDANA”) released a new set of guidelines called “GD4” outlining a series of tests that wipes must pass to be considered “flushable.” According to GD4, for a product to be deemed “flushable” there must be evidence indicating that the wipe:

  • Clears toilets and properly maintains drainage pipe systems when the suppliers recommended usage instruction are correctly followed;
  • Passes through properly maintained wastewater conveyance systems and is compatible with wastewater treatment, reuse, and disposal systems without causing system blockage, clogging, or other operational problems; and
  • Is unrecognizable in effluent leaving on-site and municipal wastewater treatment systems and in digested sludge from wastewater treatment plants that are applied to soil.

In addition, the International Water Services Flushability Group (“IWSFG”) has also released a Publicly Available Specification “PAS” to provide criteria for product manufacturers, governmental agencies, and other entities that want to determine if products that are flushed are safe for wastewater infrastructure. Table 1 highlights the differences between tests associated with ISWFG PAS and the INDA/EDANA GD4. However, while these guidelines are available,many consumers and wastewater industry professionals have claimed that “flushable” wipes are still not disintegrating fast enough and are clogging pipes across the United States.

Aside from the lack of regulations, another issue with “flushable” wipes is they are similar in function and appearance to wipe products that are specifically designed to be disposed of in the trash. For example, baby wipes or facial wipes, which are marketed as “non-flushable" are still being flushed by consumers due to their similar appearance. Because both “flushable” and “non-flushable” products are not breaking down fast enough, if at all, homeowner and municipal sewer pipes are getting clogged (see Figure 1). When this occurs, cities are spending thousands of dollars on equipment repair and replacement. In fact, according to the National Association of Clean Water Agencies, the problem related to “flushable" wipes and related clogging issues is estimated to cost U.S. utilities up to $1 billion annually.


There have been a number of campaigns and public service announcements warning consumers of products that should and should not be poured down drains or flushed in toilets (see Figure 2 and Figure 3). Many agencies recommend only toilet paper and human waste be flushed. Flushable wipes, feminine products, paper towels, and diapers can clog a toilet or sewer line and should be disposed of properly in the trash.


To help reduce build ups caused by wipe masses, ParkUSA offers several products that are great solutions to mitigate blockages caused by “flushable” wipes.

Grinders: ParkUSA Grinder Assembly is an Inline Grinder recommended for use on gravity flow sewer lines which may experience high solids that can clog sewer piping. ParkUSA Grinders reduce a variety of materials including sanitary wipes, rags, wood, paper, shoes, sludge and more. These units are proven to reduce pump clogging, protect process and dewatering equipment, reduce solids, and keep wastewater systems running properly. The ParkUSA Pump Trooper line offers a grinder pump, which is a high-powered pump fitted with sharp cutters to shred solids and move them under high pressure, usually in a relatively small diameter pipe. Grinder Pumps are designed to disintegrate or grind solids in wastewater, thus reducing discharge pipe size and creating a pressurized system.

Screens: The ParkUSA BarScreen is a stationary screen device used for wastewater or stormwater applications. Bar Screen assemblies are used in an open channel (free surface) flow applications to separate & detain coarse debris and contraband. These unusual solids have a potential for clogging the public sewer line, causing expensive cleaning and downtime of the sewer system.

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Flushable Wipes White Paper

Flushable Wipes White Paper


Felisa Cantu

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large group of synthetic chemicals used to manufacture a number of products for their heat, water, and stain resistant properties. Two of the most extensively produced PFAS chemicals have been perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS).

PFAS, PFOA, and PFOS are used in a variety consumer and industrial applications. For example, these chemicals are used in food packaging, non-stick cookware, stain-resistant fabrics, and certain types of firefighting foams called aqueous film forming foams (AFFF), which are used to extinguish fuel and chemical fires at airports, military bases, industrial sites, and fire training centers.

Certain PFAS, like PFOA and PFOS, are very persistent in the environment as they do not break down when exposed to air, water, or sunlight. As a result, PFAS have been termed the “forever chemicals” as they can remain in our bodies and persist in our environment for decades.


Studies have found that certain types of PFAS, particularly those with long chains of carbon like PFOA and PFOS, may be linked to adverse human health effects. Due to these health concerns, the EPA has been called upon to regulate PFAS chemicals.

In 2009, the EPA issued its first health advisory regarding PFOA and PFOS to assist state and local entities in regulating these contaminants for which no maximum contaminant level (MCL) had been set. The EPA’s original health advisory recommended set levels of PFOA and PFOS in drinking water at 400 and 200 parts per trillion (ppt), respectively. However, in 2016 the EPA issued a new health advisory setting a much lower threshold for both contaminants: 70 ppt.


In February 2019, the EPA released its PFAS Action Plan, which discussed the agency’s current and proposed actions to address these substances under its various statutory authorities. The plan proposed the following:
    • Drinking Water: establishing MCLs for PFOS and PFOA
    • Cleanup: listing PFOA and PFOS as hazardous substances and issuing interim groundwater cleanup recommendations
    • Enforcement: using available enforcement tools to address PFAS exposure in the environment
    • Monitoring: considering PFAS chemicals for listing in the Toxics Release Inventory
    • Research: developing new analytical methods to detect more PFAS chemicals
    • Risk Communications: creating a PFAS risk communication toolbox  


Since the 1970s, the Department of Defense (DoD) has used AFFF formulations that contain PFOS and PFOA to extinguish fuel fires. In fact, these fluorinated surfactants are specifically mandated in military specification MIL-F-24385F. However, the release of these chemicals into the environment during training and emergency responses has been a major source of PFAS contamination in ground water on military bases.

In 2016, the DOD stopped land-based use of AFFF in training, testing, and maintenance to prevent future PFAS contamination releases into the environment. When the DOD must use AFFF in emergencies to save lives, releases are now treated as a spill. Affected soil is contained and removed, ensuring no further PFAS is added to the groundwater. In addition, under the Comprehensive Environmental Response, Compensation and Liability Act (CERLA), also known as Superfund, the DOD has conducted studies to identify and appropriately address contaminated sites.

Looking ahead, the department has partnered with both the Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) to invest in the research of fluorine-free alternatives. The ultimate goal of the research is to find replacement technology for AFFF that’s better for the environment yet meets the strict military specifications to save lives. Researchers are also being called on to investigate the ecotoxicology of these alternatives to avoid moving to a new chemical and later discovering it has an adverse environmental or health impact. Other defense research includes innovations to speed up cleanup and better tools to understand how these chemicals move and transform in the environment.


The 116th Congress has introduced more than 35 bills to address PFAS. Multiple bills, including the House and Senate passed National Defense Authorization Act (NDAA) bills (H.R. 2500 and S. 1790), would direct the EPA to take regulatory and other actions to address these emerging contaminants under several environmental statutes. Several SDWA-related bills would direct the EPA to establish a drinking water standard for one or more PFAS, require monitoring for PFAS in public water supplies, and authorize grants to communities to treat PFAS in drinking water. Examples of these bills are highlighted in Table 1 below.


Although the EPA issued its PFAS Action Plan in February 2019, many states have taken their own measures against PFAS pollutants. As a result, states have adopted a patchwork of regulations and standards. Currently, there are 16 states that have formal policies addressing PFAS (see Figure 1), and at least seven states have policies or have indicated they are pursuing policies stricter than EPA’s current health advisory of 70 ppt for PFOA and PFOS.


ParkUSA manufactures a wastewater treatment system to protect and reduce the risk of PFAS contamination in the environment. Specifically, the ParkUSA Foamtrooper® targets AFFF discharge during a fire event in airport and hangar applications.

The Foamtrooper® system is designed to divert wastewater from hangars to a holding tank in the event of an AFFF discharge. The typical system consists of the following components listed below:

- Diversion Valve Vault;
- AFFF Holding Tank;
- Vent Drain Vault;
- Drain Vault;
- Oil-Water Separator;
- Sample Well;
- System Control Panel; and
- Trench Drain.

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PFAs White Paper

PFAs White Paper


Felisa Cantu


Felisa Cantu


In September 2018, the National Oceanic and Atmospheric Administration (“NOAA”) published a new study, called Atlas 14 Volume 11, that found increased rainfall frequency values across Texas. More specifically, the analysis found that major cities, like Austin and Houston, are more likely to experience a major storm event than previously expected, thus increasing the likelihood of severe flooding (see Figure 1). To prepare for the increased flood risk, the City of Austin has developed proposed changes to the City Code which includes tighter regulations that impact existing and future infrastructure.


The updated NOAA Atlas 14 results in significant changes to Austin’s rainfall amounts that define the City’s current “100-year storm” event. A 100-year storm is defined as the amount of rain having a one percent chance of being equaled or exceeded in any given year, or 26 percent chance of occurring during a 30-year period.

Based on existing data, the City of Austin defines a 100-year storm event as 10.2 inches of rainfall depth in a 24-hour time period. However, the new Atlas 14 study for Texas shows that this rainfall amount is likely to occur more frequently. NOAA’s Atlas 14 defines the new 100-year storm for the city to be closer to 13 inches of rainfall depth in a 24-hour period, which resembles the current 500-year storm (see Figure 2).

The Atlas 14 study also impacts the existing floodplain zones in the City of Austin. A floodplain is the land which has been or is expected to be covered during a regional flood.  Given Atlas 14’s new historical data, this information indicates that more people and property are at risk of flooding. To account for this increased flood risk, the City of Austin is proposing to rezone the City so that the new 100-year floodplain will be based on the existing 500-year floodplain. These new, larger flood zones will encompass nearly 700 more Central Austin properties than before (see Figure 3).


The City of Austin regulates new development, redevelopment and remodeling in the floodplain. These regulations are meant to protect residents from flooding and reduce public expense in the aftermath of a flood. As a result of the Atlas 14 Study, the City of Austin is proposing to change City code in order to protect the public from flooding.
The proposal has four main components, as outlined below:

  • The proposal uses an interim 100-year floodplain, based on the current FEMA 500-year flood insurance rate map, to regulate development. This change means that the floodplain regulations will apply to more properties. Property owners and businesses in the interim 100-year floodplain would have new restrictions if they want to develop, expand, remodel or improve their properties. The City of Austin estimate that there are approximately 7,200 buildings in the interim 100-year floodplain.
  • The City of Austin includes a new exception that will allow for the administrative approval for redevelopment of a residential building in the floodplain that reduces flood risk. Currently, this often requires approval by the Austin City Council.
  • The proposal recommends expanding an existing exception that allows for a building to encroach on the 100-year floodplain of the Colorado River downstream of Longhorn
    Dam and along Lady Bird Lake to also include Lake Austin and parts of Lake Travis.
  • The proposal recommends an increase in the freeboard requirement for buildings from one foot to two feet.


Aside from new City regulations that will impact property owners, the Atlas 14 Study also has additional far-reaching impacts as outlined below:

  • Flood Insurance – The City of Austin estimates that the number of buildings in the 100-year floodplain could increase from 4,000 to 7, 200. Affected residents who have federally-backed mortgages will eventually have to purchase flood insurance. Those who already have flood insurance will likely see the costs go up. This will affect businesses, too. Residents and business owners in the interim 100-year floodplain should talk to their insurance agent about purchasing flood insurance. Impacts to flood insurance will occur after FEMA approves updated floodplain maps, estimated to occur in 2023 or 2024.
  • Pipes and Ponds – Both public and private storm drain pipes, bridges, detention ponds and other drainage infrastructure will need to be larger to handle the changes associated with updated design requirements for the new storm levels.


Since September 2018, Austin’s Watershed Protection Department has held meetings to gather input from various stakeholder groups and the public. Following all public hearings, the Austin City Council will consider adopting the proposed regulations.

Interested in attending? The tentative schedule for the remaining public hearings about the proposed regulations are highlighted below:
     • Zoning and Platting Commission – Tuesday, September 17, 2019
    • Planning Commission – Tuesday, September 24, 2019  
    • Austin City Council – Thursday, October 17, 2019

For more information, visit the City of Austin’s official website:

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Austin White Paper

Austin's increased rainfall frequency  White Paper


Felisa Cantu

NOAA’s Atlas 14

Felisa Cantu


Across the United States, we use historical rainfall data to predict rainfall intensity and flood risk. To do so, accurate information on rainfall amounts is essential. The National Oceanic and Atmospheric Administration (NOAA) is the agency of the United States federal government responsible for providing data and forecasts for weather and water cycle events.


The initial national rainfall data analysis began in 1935, evaluating data obtained from only 200 Weather Bureau stations. Starting in 1955, the Weather Bureau coordinated their efforts with the Soil Conservation Service and published Technical Paper 40 (TP-40) in 1961. NOAA published two additional documents supplementing TP-40, TP-49 in 1964 and Hydro-35 in 1977.

TP-40 is still widely used and includes maps for various storms where the user can estimate rainfall depths from the isopluvial lines. Recognizing the data used in developing TP-40 was collected prior to 1961 and had limited spatial coverage, NOAA, with funding from various sources, began data analysis for Atlas 14.


NOAA’s Atlas 14 is an ongoing study used to analyze historical rainfall data and predict the likelihood of a rainfall event in any given year. The study contains the latest rainfall data and has been completed across most of the United States, with different volumes based on geographic region of the country (see Figure 1). However, there are five remaining northwestern states that rely upon NOAA’s older Atlas 2 rainfall data, as no funding is available to update estimates for NOAA Atlas 14 coverage.


The Hydrometeorological Design Studies Center’s (HDSC) team of scientists, mathematicians, statisticians, and meteorologists analyze precipitation volume data to help us prepare for major storm events. Precipitation volume data is based on rainfall intensity, duration and frequency estimates from historical data collected from observing stations across each geographic region. The Atlas 14 rainfall data can be obtained at https://hdsc.nws.noaa.gov/hdsc/pfds/.


Here are three examples supporting the development of Atlas 14:

Atlas 14, Volume 8 – Midwest
The states within the Midwest Region have historically used TP-40 (1961), TP-49 (1964) and Hydro-35 (1977). In 1992, NOAA released a publication called Rainfall Frequency Atlas of the Midwest, more commonly known as Bulletin 71, which served as an updated source for rainfall frequency. Each of these reports focus on different rain event durations and return periods. In 2013, NOAA completed Atlas 14, Volume 8, giving the midwest states once source of data covering rain event durations ranging from five minutes to 60 days with return periods between two years through 1,000 years. Using NOAA Atlas 14 data, storm event definitions in Southeast Michigan have increased by 1 to 2 inches for various design storms.

Atlas 14, Volume 10 – North East
The states within the North East Region have historically used TP-40 (1961), TP-49 (1964 and Hydro-35 (1977). Thirty years later, following the completion of the NERCC Extreme
Precipitation analysis in 2010, states within the region had a fourth data source. Each of these reports focus on different rain event durations and return periods. In 2015, NOAA completed Atlas 14, Volume 10, giving the Northeastern states one source of data covering rain event durations ranging from five minutes to 60 days with return periods between two years through 1,000 years. Much of Massachusetts has seen a 1- to 2- inch increase in the 24-hr/100-year storm.

Atlas 14 volume 11 – Texas
Texas has historically used TP-40 (1961), TP-49 (1964) and Hydro-35 (1977). The United States Geological Service (USGS) and Texas Department of Transportation (TXDOT) developed depth duration frequency data which was published in 1998 and updated in 2004. In 2018, NOAA completed Atlas 14, Volume 11, giving Texas one source of data covering rain event durations ranging from five minutes to 60 days with return periods between two years through 1,000 years. The central and coastal regions of Texas have shown an increase in occurrence and intensity of major storm events: Austin area realizing 2- to 2 1/2- inch increase in the 24-hr/100-year storm; Houston area realizing 3- to 5- inch increase in the 24hr/100-year storm.


Atlas 14 provides improved storm predictions that will allow for appropriate adjustments to stormwater management systems. Using NOAA’s Atlas 14 for the management of stormwater will allow municipalities and designers across the US to make the appropriate adjustments needed to increase the useful life of infrastructure and protect communities and water resources from unnecessary risk.

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NOAA's Atlas 14 White Paper

NOAA'S Atlas 14 White Paper


Felisa Cantu






The traditional approach to stormwater is to move the water as fast as possible away from businesses and homes. Different means of conveyance include underground systems, concrete lined channels, and open ditching. During a heavy rain event, when the underground infrastructure is at full capacity, roadways often become a secondary form of conveyance. This method of moving stormwater transports terrestrial pollutants into receiving streams, lakes, oceans and other water bodies as well as increased flows and velocities in those water bodies; impacting the water quality and quantity downstream.


Development within a watershed often results in increased impervious cover which in turn changes the water budget. The increase in volume and rate of runoff from a site as well as the reduction in ground water recharge is directly related to the increase in impervious surface within the watershed. The increased runoff contributes to downstream flooding and reduced groundwater recharge.


One management strategy that focuses on maintaining pre-development hydrology is low impact development (LID) which includes integrated management practices known as green infrastructure (GI). LID/GI techniques focus on keeping the runoff close to its source and mimicking pre-development hydrology by using infiltration; filtering; storage; evaporation; and detention. The philosophy is to keep the water safely on-site as long as possible, use small distributed features located on-site to mitigate and treat runoff and take advantage of nature. Increased roughness, infiltration, soil modification and on-site storage are LID methods.

Increase in roughness can be accomplished by minimizing impervious cover, disconnecting impervious services, forcing water to pass over vegetated areas, allowing impervious surfaces to drain into natural areas and planting grasses or vegetation in swales to slow velocities. Increase in infiltration and/or on-site storage can be accomplished by the use of pervious paving, native vegetation, green roofs, rain gardens, bioswales, vegetated filter strips, on-site detention and manufactured treatment devices.

LID is supported through federal, state and municipal regulations. For example, the Energy Independence and Security Act of 2007 requires federal development projects with a foot print exceeding 5,000 square feet to maintain or restore the pre-development hydrology of the property. Federal agencies such as the Environmental Protection Agency, Department of Defense, United States General Services, Department of Housing and Urban Development, Federal Emergency Management Agency and the Natural Resources Conservation Service of the Department of Agriculture promote and utilize LID.

An example of a municipality embracing LID is the fact that the City of Los Angeles, California has adopted an ordinance imposing rainwater LID strategies on projects that require building permits. The City requires stormwater runoff to be infiltrated, evapotranspired, captured and used, and treated onsite without allowing any runoff leaving the site for a specified design storm event. States and cities nationwide are adopting LID as an option for managing stormwater runoff. Maryland is one of the first states to implement LID. One Maryland project, Somerset Rain Gardens, realized a significant savings when rain gardens were utilized instead of conventional ponds: $100,000 compared to $400,000 respectively.

PaskUSA possesses several product lines that are great BMP options for LID projects. Below is a listing of some of our products. 


ParkUSA®’s RainTrooper® is a solution for commercial and residential applications to conserve as much rain as possible to store for future use and to reduce consumption of the limited treated municipal water meeting LID design goals. The RainTrooper is designed with the following components: catchment devices, debris filtration, flush diverters, water storage tanks, pump systems, and water disinfection systems.

The ParkUSA® RainFilter™ is a complete system designed to treat total suspended solids (TSS), debris, and trash from stormwater runoff. It presents a low footprint, consists of a high-density polyethylene (HDPE) tank, an internal stainless-steel filter, and an optimal storage system.

The ParkUSA RainBasin® is a stormwater detention system designed to mitigate the effects of new development and redevelopment on an existing drainage system. In addition, the system can be used for the management of storable and reusable stormwater runoff through ground water recharge or rain harvesting. The RainBasin is a system that affords the designer the opportunity to maximize the developed land by placing the detention easily underground such as under parking lots and roadways with minimal cover, as well as being a LID technique.


The ParkUSA® FilterBasin™ is a family of stormwater best management practice (BMP) devices designed to fit within common basin structures to provide an economical BMP solution. These basins present an opportunity to pre-filter the stormwater prior to discharging into rain gardens and storm sewers.


The TreeBasin™ is a biofiltration BMP that can be used in LID applications like stand-alone treatment, pretreatment for infiltration, rainwater harvesting, and detention. The TreeBasin system uses a combination of physical, chemical, and biological processes to remove nutrients, sediments, hydrocarbons, metals, and trash from stormwater. The TreeBasin uses an engineered filtration/absorbing media which presents the ideal characteristics to grow a tree. TreeBasins are highly adaptable for most developments due to a small footprint and shallow elevation. Plant selection allows TreeBasins to be seamlessly integrated into the landscape and adds aesthetic value. Typical TreeBasin applications include parking lots, sidewalks, plazas, and streets.

The NutriBasin™ is a filtration device designed to remove dissolved nutrients (e.g. phosphorus and nitrogen) from stormwater runoff with high removal rates for phosphorous (above 90% removal). It consists of a concrete vault with top access hatchway; inlet and outlet pipe connections; and an engineered biofiltration media contained in removable cartridges. The NutriBasin™ design allows for easy maintenance. All servicing can be done without entering the vault, which avoids confined space hazards.

The MarshBasin™ is a wetland treatment BMP: an engineered ecosystem that emulates the natural wetland’s ability to improve water quality and is a LID technique. The MarshBasin can be used in stand-alone applications, pretreatment for infiltration, rainwater harvesting, and detention applications. It uses a combination of physical, chemical, and biological processes to remove nutrients, sediments, hydrocarbons, metals, and trash. The MarshBasin design allows for use from small urban areas to highly developed cities.The MarshBasin is highly adaptable for most developments due to its small footprint and shallow elevation. Typical applications include parking lots, sidewalks, plazas, and streets.

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LID Stormwater White Paper

LID Stormwater White Paper