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

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.

[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.