Biosolids Corner, October, November, December 2021      By Diane Garvey

Potential Changes to General Permits for Land Application of Biosolids and Septage


On March 18, 2021, the PADEP made a presentation to the Agricultural Advisory Board (AAB) about potential changes to the General Permits for Land Application. The PowerPoint presentation, found on the PADEP website, included the following bullet points.

  • Biosolids land application would be subject to the Phosphorus Index just like Concentrated Animal Feeding Operations (CAFOs) and Concentrated Animal Operations (CAOs)
  • Water Resource Recovery Facilities (WRRFs) would be required to monitor biosolids for PFAS
  • Some plants that accept trucked in waste would no longer be eligible for coverage under the General Permits PAG-07 (Exceptional Quality or EQ), or PAG-08 (Non-Exceptional Quality or Class B)

PADEP released a pre-draft version of the revised permits for discussion by a Biosolids Workgroup. This workgroup will include people from PWEA, the Agriculture Advisory Board, the Water Resource Advisory Council and academia.  PADEP plans to finalize the revisions to the permits during the first quarter of 2022.


The purpose of this report is to comment on the impacts that these pre-draft changes to permits PAG-07 (EQ) and PAG-08 (Class B) will result. The pre-draft highlights significant changes. It is not easy to compare the existing and the pre-draft because it is reorganized. This report does not include the results of a line by line review of the predraft.


These changes are so significant, they should be a regulatory change, not a permit modification. By changing the permit instead of the regulations, the PADEP will not be required to do a cost benefit analysis.  This means any argument about the economic impact to WRRFs and ultimately anybody who flushes does not have to be addressed by PADEP.


The P-Index:

The presentation mentions “Addition of P-Index based land application rates requirements.” The implication is that every farm and field that receives biosolids may need Phosphorous “P” Index.  Requiring a Nutrient Management Plan or a Phosphorus Index for every farm and field that receives biosolids would have a profound effect for both Non Exceptional Quality (usually Class B) and Exceptional Quality biosolids programs.


The P Index was developed by studying soil treated with manure. The research used showed that when soil treated with manure reached 200 ppm P, there was an increase in soluble P in the nearby surface water.  This has not been studied for fields amended with biosolids, which have a far lower solubility of P than manure. The standard for manure should not be applied to biosolids without further study. Concentrated Animal Feeding Operations (CAFOs) and Concentrated Animal Operations (CAOs) are currently required to use the P Index. Farms using biosolids are nowhere near as nutrient intensive as CAFOs or CAOs. CAFOs and CAOs will have 2 or more Animal Equivalent Units[1] per acre living on the farm 365 days a year. Biosolids managers do not rely on spreading on every field every year. In fact, a common rule of thumb is that a biosolids manager must have 3 to 4 times as many acres permitted as they can spread in a year.  Another example of why biosolids programs are a significantly lower threat to P migration to surface water than manure is that the typical Phosphorus Source Coefficient[2] (PSC) in biosolids[3] is 0.1 and manure PSC is 0.8 to 1.0.  Soluble P migration from fields receiving only biosolids with a PSC of 0.1 has never been proven. In a presentation to the Mid Atlantic Biosolids Association, Dr. Jennifer Weld, who developed the P Index, said that more field work on P loss from fields was needed. Research should be conducted to develop a P Index specific to biosolids.


What does the P Index determine and what determines the P Index?

  • A low P Index result will allow you to continue applying biosolids at the rate to meet the crop nitrogen demand. That will be fine for a while, until the soil P reaches 200-250 ppm.
  • A medium P Index will limit your application rate to that needed to meet the crop phosphorus demand. This would result in a lower application rate that would not meet the crops nitrogen demand. The farmer would have to spread fertilizer anyway. Experienced land appliers say it is not feasible to apply biosolids on fields limited to crop Phosphorus demand.
  • A high P Index would mean no biosolids could be applied until and if the soil P is reduced.


What determines the P Index?


First there are screening criterial to determine if the full P Index must be conducted. If the answer to any of the following is yes for a field the full P Index must be conducted.

  1. Is the field in an Exceptional Value[4] or High Quality Watershed?
  2. Is any portion of the field within 150 feet of surface water?
  3. Is the soil P concentration over 200 ppm?
  4. Is winter spreading of biosolids planned for this field?


For each field you must create a map and find the following information;

  • Average slope, length of slope, distance from surface water, distance from wells, distance from drain pipes
  • Soil classification, soil texture, soil permeability, soil erodibility, tillage practice, crop grown, type of vegetation between the field and surface water
  • Predicted soil loss in tons per acre using the RUSTLE 2 equation
  • Soils sampling and analysis for P concentration (must be redone every 3 years)
  • Biosolids analysis for P and Phosphorus Source Coefficient (PSC).
  • Is the biosolids surface applied or incorporated? Days between spreading and incorporation?
  • Time of spreading, winter field conditions, winter cover crop, length of storage
  • Any other sources of P applied to the field and rate
  • Frequency of biosolids and/or manure application over the past 5 years


Based on the above information, numeric values are assigned and must be plugged into a spread sheet to get the P Index value.


Exceptional Quality Biosolids that is land applied under the control of the permittee is required to provide P-index based application rates or provide P content of sewage sludge on the fact sheet of the permittee.


Non Exceptional Quality Biosolids -

The most recent version of the Pennsylvania Phosphorus Index must be used to determine the appropriate biosolids application rate. Biosolids application shall be in accordance with Phosphorus Index loading rates, unless that rating allows for agronomic loading rates based on nitrogen. Existing farms must do this within 2 years. New farms will be subject to this requirement immediately.


Nutrient balance evaluations for biosolids application areas shall be updated and submitted to DEP every three years and more frequently if any of the following occur:

i. Significant changes to farm operations, such as a change in manure management or use of alternative fertilizers.

ii. A change in field areas or the available acreage for biosolids application.

iii. A change in the source of biosolids proposed for use on the farm.


Why P-Index should not be applied to Non EQ Biosolids:

  • Requiring a P-Index will be a hardship on the farmers. Many farmers who have given up their animal operations rely on biosolids as a source of nutrients. Changes to the General Permits will make it harder for farmers to obtain biosolids and increase the farmer’s costs to raise crops.
  • If implemented, farms that have been using biosolids for several years could no longer receive biosolids due to phosphorus built up in the soil.  This would require WRRFs and/or their contractors to find new farms and these will probably be farther away. It is very time consuming to determine the P Index for every field where biosolids is used. The proposed 2 years to implement the P Index requirement will not be adequate to find and permit new farms.
  • The P Index is required for CAFOs and CAOs. These operations are much more nutrient intensive than farms receiving biosolids. Applying the P Index to fields that only receive biosolids once every 3 or 4 years will result in higher costs for recycling biosolids and more biosolids will be diverted to landfills.
  • In a presentation to the Mid Atlantic Biosolids Association, on July 20, 2021, Dr. Jennifer Weld, Penn State University, who developed the P Index, said that more field work on P loss from fields was needed. Research should be conducted to develop a P Index specific to biosolids.

Depending on the details, companies like Jessie Baro (now Denali) and Synagro say costs will go up by 35% assuming they can find additional suitable farms with low P concentrations in the soil. It is possible that in some cases, land application may no longer be feasible. It is probable that less biosolids will be recycled and more will be disposed in landfills. If biosolids cannot be land applied and must be disposed in a landfill the costs are likely to double or triple. This is what happened in some New England states.



Monitoring Biosolids for PFOS and PFOAs ([5]:

The proposed monitoring for PFAS could be very expensive and would have a negative effect on public acceptance. The proposed frequency is the same frequency as monitoring for metals and PCBs which varies from one to twelve times per year. At this point in time, there are no approved lab procedures for measuring PFOS and PFOAs in biosolids. How can you evaluate the data if various labs are using different analytical procedures?  The cost is approximately $400 per test and only a few labs in the country are providing this service. The cost of sample collection could exceed $1000 per monitoring event. At this time, there are no Federal or PA state standards for PFOS and PFOAs in drinking water, groundwater, soils, or biosolids so it is unclear what levels they will be looking for. The effort to start collecting data for biosolids before methods are standardized, before we have a safe standard for soils and water, would be a waste of time and money. There is plenty of data available on typical levels of PFAS in biosolids right now. There is an international database available on the New England Biosolids and Residuals Association web site.


There are concerns with plant uptake and eventual ingestion. This is something that an upcoming EPA study will be determining. In addition, multiple research projects showed plant uptake is not a concern.

PFOS and PFOAs contained in land applied biosolids are not a significant source of human exposure.

A June 2019 article by Sally Brown PhD. at the University of Washington cited various studies that correlated human PFAS contamination in the blood to a wide range of products ranging from stain resistant carpeting to non-stick cook ware to the consumption of shell fish to use of dental floss. Per Dr. Brown, “In other words, these compounds are in biosolids and composts because they are ubiquitous in our homes. If we want to lower the concentrations in the biosolids, we should ban the compounds - as we have done with other persistent chemicals of concern. Prohibiting or severely restricting use of composts or biosolids because of these compounds will have no impact on human exposure. “


Some products that may contain PFAS include: 

  • Some grease-resistant paper, fast food containers/wrappers, microwave popcorn bags, pizza boxes, and candy wrappers 
  • Nonstick cookware 
  • Stain resistant coatings used on carpets, upholstery, and other fabrics  
  • Water resistant clothing
  • Cleaning products and fabric softener
  • Personal care products (shampoo, dental floss) and cosmetics (nail polish, eye makeup) 
  • Paints, varnishes, and sealants 
  • textile impregnation
  • fire-fighting foam
  • electroplating
  • ammunition
  • climbing ropes
  • guitar strings
  • artificial turf


In fact, household dust contains PFAS in concentrations more than 4 times higher than biosolids.


It’s also important to note that PFAS levels will decrease over time since some PFAS manufacturing and use has been discontinued. Fifteen years ago the manufacture of PFOA and PFOS were voluntarily phased out. Since then, the levels of these compounds in human blood was decreased by 75%.


Monitoring conducted in 2022 will not be representative of biosolids quality in 3 or 4 years because PFAS concentrations will be going down.


Trucked in Waste:

Another proposed change mentioned in the DEP Pre-draft would affect WRRFs ability to land apply biosolids if they accept trucked in waste. The following is an excerpt from the presentation;

"Prohibition of mixing wastes with sewage sludge. • Hauled-in waste acceptance and Treatment Facility • If not incorporated into the head of the plant, the biosolids are not sewage sludge."


This means that WRRFs with trucked in waste programs, where the waste is not put in at the head of the plant, would not qualify for coverage under the PAG-07 or PAG-08.  They could still land apply but would need either an individual permit or general permit under Section 271, Subchapter I. Both of these alternative permitting scenarios are very time consuming and/or more restrictive than our current system. This would place a tremendous burden on an already woefully understaffed PADEP. Before the existing General Permitting system for biosolids was in place it could take 5 years or more to get an individual permit. More recently, an individual permit for an Exceptional Quality product produced in Schuylkill County took 12 years.


Many plants have spent or plan to spend millions of dollars to enhance digester performance and generate energy by introducing high strength wastes directly to the digester.


The benefits of taking in high strength waste include:

  • Generates revenue for the WRRFs  and can lower rates to sewer users
  • Increases digester gas production which can be used for combined heat and power
  • Offsets digester heating costs
  • Generates electricity to offset usage and save money
  • Feeds electricity back to the power grid and generate revenues
  • Diverts high strength waste from the landfill thereby reducing greenhouse gases generated at a landfill

Where will the biosolids go if they can no longer be land applied?


Most landfills in PA are already over committed on the amount of biosolids they accept and no new landfills have been proposed. If plants can't recycle their biosolids, long haul distances and high tipping fees will easily double the cost of biosolids management. As previously stated , increasing costs will have no impact on DEPs decision because a permit change does not require a cost benefit analysis whereas changes to the regulations would require that cost be considered.


What is the reason PADEP wants to implement these changes?


It is thought by some that the Watershed Implementation Plans (WIPs) are not meeting their goals of reducing P in surface water including the Chesapeake Bay. However, the amount of P from biosolids that is land applied is miniscule compared to that from fertilizers and manure. If all those Nutrient Management Plans implemented for CAFOs and CAOs have not enabled PA to achieve those WIP goals, will requiring a P Index, individual permits or monitoring for PFAS have any impact? Probably not, but it will certainly have a cost impact on everyone who flushes.


It is unknown why DEP wants to require PFAS testing or restrict recycling of trucked in waste.


Environmental Impacts


Another drawback of the proposed permit changes is that less biosolids will be used in agriculture and more biosolids will be landfilled.  


What about Environmental Justice[6]


Just think for a moment, who will ultimately be paying for these potential changes to biosolids management in PA? The WRRFs will have to pass these costs to sewer users. Septic tank pumpers will have to pass the costs along to homeowners. Landlords will have to pass these costs along to renters.  Many of these people are on a fixed income or have no disposable income. Where are they going to get the money to pay for higher sewer bills or higher rent?


If the intention of these proposed permit changes are to achieve water quality goals in the Chesapeake Bay who will benefit? The rich people with mansions on the Bay and people with enough disposable income to enjoy recreational boating and vacations. However, this will not be considered in a permit change because PADEP is not required to perform a cost benefit analysis. 


What can be done?


The Eastern Pennsylvania Water Pollution Control Operators Association (EPWPCOA) has started an Ad Hoc Commitee to discuss the potential impacts and to reach consensus on what our message to DEP should be. The PWEA Biosolids Committee Chair, Charles Winslow, has participated in the EPWPCOA meetings and has communicated with the PWEA Board of Directors. This Board encouraged the PWEA Biosolids Committee to prepare to communicate with PADEP and to deliver a consistent message as the Eastern, Central and Western Operators Associations.


PWEA is not a lobbying organization but the PSMA and PA Municipal Authorities Association (PMAA) have access to lobbyists. These lobbyists can be used to inform legislators of the environmental impacts and costs associated with these potential changes to the General Permits.


It is also important that the regulated community should contact the PADEP and inform them of the economic impact this will have on their operations and their customers. At a minimum, a full cost accounting and benefit analysis should be considered before such changes are proposed.


[1] An animal equivalent unit is equal to 1000 lbs of livestock, for example, approximately 1 cow or 1 horse.

[2] PSC is a laboratory test that measures the solubility of P in manure and biosolids. The scale ranges from 0.1 to 1.0.

[3] The exception to PSC of 0.1 in biosolids is when the WRRF employs biological phosphorus removal in which case testing has shown typical PSC in the 0.4 range.

[4] Already biosolids are not allowed to be land applied in an Exceptional Value watershed but the High Quality watersheds are much more numerous.

[5] Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries since the 1940s. Although PFOA and PFOS are now banned, they were used in firefighting foamfast food containers/wrappers, microwave popcorn bags, pizza boxes, candy wrappers, nonstick cookware, stain resistant coatings used on carpets, upholstery, and other fabrics, water resistant clothing, cleaning products and more. PFAS are found almost everywhere including in most public water supplies, wastewater and biosolids.

[6] Environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income, with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies.



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