Innovative Land Application Project Using Hybrid Poplars

In response to an RFP to the Philadelphia Water Department, Garvey Resources assisted in the development and preparation of a proposal to use Class B biosolids to establish a tree farm on mined land in need of reclamation. 


Biosolids were used as a sub-surface fertilizer to establish and support a vigorous stand of hybrid poplar trees.  Hybrid poplars, a quick growing species, are receiving much interest as a green energy resource and as a tool that can be utilized in the reclamation of disturbed sites.  An advantage over traditional means of biosolids land application is that this technique will significantly reduce the need for stockpiling and virtually eliminate any off-site odor issues related to incomplete incorporation.


Hybrid poplar use has recently expanded from past traditional use in windbreaks to producing wood/fiber/fuel products and to remediate contaminated sites and treat waste.  These hybrids are also capable of using more water and nutrients, which make them ideal for waste management applications.  Coal burning power plants are planning on using this means of rapid biomass production to earn carbon sequestration credits to offset emissions of greenhouse gases.


Garvey Resources worked with local environmental groups to distribute information about this innovative technique and to build public support early in the project.  We also developed the plan for an Environmental Management System for this project.


Hybrid poplars are among the fastest growing tree species in North America.  They are capable of accumulating enormous amounts of wood and biomass in a relatively short period of time.  With proper care and selections of appropriate varieties, poplars can also sequester enormous amounts of carbon dioxide in a short period of time.  Wood products manufactured from poplar trees can make this sequestration permanent.  Poplars, for this reason, have received considerable attention as a potential tool to help combat global warming.


The ability to establish these trees as a useful crop may serve purposes beyond the restoration of mined lands.  If trees can be used to restore mined land across the commonwealth, those businesses that rely on forestry resources may provide economic growth and development within the region.  Furthermore, the potential for these trees to serve as a fuel resource in the production of power may help reduce the dependence on fossil fuels.

Philadelphia Water Department Three-year control tree grown without biosolids
Hybrid poplars Three-year tree grown with biosolids

Abington Wastewater Treatment Plant- Biosolids Management Report

This study took a holistic approach to biosolids management decision making.  Abington Wastewater Treatment Plant, located in a residential community in the Philadelphia suburbs, had been plagued with odor complaints and escalating cost


The comprehensive study evaluated digester operation and recommended operating and mechanical changes, evaluated bench test results of various dewatering equipment, identified and evaluated end use and disposal alternatives, conducted an odor audit and conceptual design of odor control equipment, estimated costs for digestion, dewatering and end use of the biosolids.  


Some questions that were addressed in the report were: Does the cost of digestion offset the cost of downstream processing and end use or disposal?  How can we eliminate odor complaints from the neighbors?  Which is better: belt press or centrifuge dewatering?  


A paper was co-authored with the client and presented at the 2000 WEF Residuals and Biosolids Specialty Conference.  



Philadelphia Water Department

Garvey Resources conducted a study for the Philadelphia Water Department to evaluate the needs and potential revenue from a City operated septage and wastewater residuals receiving facility.  The study included development of survey instruments, interviews, regulatory review, and economic projections.


During the course of this study, nearly 50 wastewater treatment plants in the Mid-Atlantic region were surveyed to determine trends in biosolids management alternatives, costs for contracted hauling, processing, end use and disposal.  The study also identified the majority of facilities in the region that accept wastewater residuals in liquid or dewatered form, the quantities of material accepted, and the criteria for acceptance.


With our help, Waste Management & Processors, Inc (WMPI), who is a contractor for the Philadelphia Water Department, implemented an innovative technique for the beneficial use of Philadelphia’s biosolids.  With the input of ERCO, Inc of Maryland, we have been using biosolids for the restoration of mined lands.  In May and June of 2005, we planted 8 plots of Hybrid poplars at the Repplier Mine site in Schuylkill County. Mining at the site started over fifty years ago.  At that time, the environmental regulations to reclaim mine land had not been developed. The previous owner left the site ungraded and un-reclaimed. The biosolids applied to this land contributes much needed organic matter as well as nutrients such as nitrogen and phosphorous. 

We have the responsibility, with the help of WMPI and Lehigh Engineers, of taking statistical data from all the plots in addition to testing the biosolids underneath the ground and the water quality at these sites.



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Biosolids Blog

Keep informed about the latest biosolids news and trends by following Diane Garvey's Biosolids Blog.


Diane's most recent post is entitled, "Another Look at Triclosan."

News & Events

Diane will be presenting at three upcoming events in September:

EPWPCOA Meeting and Trade Show in Leesport, PA


Friday, September 16, 2016


The title of the presentation is: “The Phosphorus Index and the Impact on Land Application of Exceptional Quality and Class B Biosolids.”


The conditions of the General Permits for Land Application will be revised and reissued in April 2017 to include an evaluation of each field for the Phosphorus Index.   This presentation will evaluate the impacts of this change and provide recommendations to prepare for these new regulatory requirements.



WEFTEC 2016 – Technical Exhibition and Conference in New Orleans


Technical Session #410, “Sludge Hydrolysis,” Tuesday, September 27, 2016 at 2 PM


This will be a presentation of a paper written by Diane Garvey et. al. entitled, “Hydrolysis Process and High Solids Liquid Fertilizer Reduce Land Application Costs & Complies with Nutrient Management Regulations” 

The Issue: With the growing interest in Resource Recovery, many biosolids producers are keen to continue to recover the nutrients and organics in their biosolids through land application to agricultural lands. The traditional land application of dewatered biosolids, however, often raises concerns from regulators and the public about odors, dust and nutrient run-off. In addition, newly implemented or soon to be implemented Nutrient Management Regulations in each state will limit how much and where biosolids may be used in agriculture.
The Solution: Over the last 8 years a number of biosolids producers in Canada have made use of a biosolids hydrolysis process to overcome stakeholder concerns. This process produces a high solids EQ biosolids liquid that can be land applied in a way that offers a number of benefits to the ratepayer, the public, environmental regulators, and the farmer.



EPWPCOA Event “Beneficial Use of Biosolids in Mine Reclamation” in St. Clair, PA


Session entitled “General Permitting for Beneficial Use” on Friday, September 30, 2016 at 10:45 AM


This presentation will cover the process of General Permitting for the Beneficial Use of Biosolids, including the requirements for biosolids quality, preparation of sampling plans for biosolids permitting, and the preparation of Biosolids Quality Enhancement Plans for use in the Land Application and Beneficial Use of Biosolids.

DC Water has launched its new branded biosolids product: BLOOM. And you can learn about this project at the new website:



For more information on any of the above topics, please contact Diane Garvey at or call 215-362-4444.

Garvey Resources was a partner in the development of the Rodale Institute's Water Purification ECO-Center.  Read about it on our Biosolids Blog.

Rodale Institute ECO-Center and wetland.

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