of conventional fuels can also reduce greenhouse gas and conventional air pollutant emissions. Several recent projects shed light on the innovations, successes, and problems that are occurring when using waste grease resources.


Undercover No More
Using an EMS to increase public outreach, enhance biosolids management program

Mitchell A. Costanzo and Becky Patterson

The Metro Wastewater Reclamation District in Denver generates about 73 dry Mg/d (80 dry ton/d) of Class B anaerobically digested biosolids that are marketed under the trade name METROGRO® Cake. Ninety percent of METROGRO Cake is transported up to 121 km (75 mi) from the district’s central treatment plant (CTP) and applied to agricultural land in eastern Colorado. During inclement weather, biosolids are composted at the CTP. On average, about 10% of the biosolids is composted to meet Class A criteria and sold as METROGRO Compost to golf courses, landscapers, and homeowners in the metropolitan Denver area.

Historically, the production, transport, and distribution of METROGRO Cake was performed “under the radar,” and every attempt was made to draw as little attention as possible. In addition, the district’s purchase of 21,000 ha (52,000 ac) of farm property for the dedicated purpose of land-applying biosolids was approached as a private instead of public matter. However, public responses to the district’s biosolids operations and its move into the farming community were sometimes negative and often ill-informed. Public concern even halted biosolids operations on a portion of the METROGRO Farm at one point.

The need for a change in attitude was recognized, and the district’s public relations efforts began in earnest. The National Biosolids Partnership (Alexandria, Va.) Environmental Management System (EMS) for Biosolids provided a comprehensive and systematic approach to public outreach planning, evaluation, and implementation. Biosolids production and product information is now promoted in multiple media and also during CTP and farm tours and demonstrations. Stakeholder groups are in place for the EMS program, major studies, and the METROGRO Farm monitoring program. Facilitating communications, access, and availability to the public is helping promote the district’s sustainable biosolids management program.


Stop a Moving Target
Minimizing process modification requirements in a changing biosolids environment

Patricia Scanlan, Jeannette Klamm, and James Fitzpatrick

Wastewater and biosolids treatment requirements have long been a moving target for treatment utilities. Regulatory changes for both effluent and biosolids treatment make it difficult to design wastewater and biosolids facilities that meet current treatment requirements but also are cost-effective to support future processing requirements with minimal modification. Process modifications, especially in biosolids treatment, can mean abandoning existing facilities because the equipment no longer supports treatment needs. In some cases, existing facilities can be converted to support a new process technology, but the desire to reuse as much of the existing facility as possible can result in a design that is not ideal.

Designers typically allow space for future capacity expansions but less frequently consider supporting upgrades to meet future regulatory requirements. Modifications that increase liquid-stream capacity can have a tremendous effect on biosolids treatment processes. For example, it is common for small to medium-size plants that initially generate only waste activated sludge to replace their entire biosolids stabilization systems after primary clarification is installed. In addition to such changes resulting from liquid-stream requirements, biosolids treatment processes are also commonly modified or upgraded to support changes in final use, often driven by the availability of landfill disposal or land-application opportunities.

A design that incorporates flexibility for future treatment upgrades and capacity expansions will minimize expansion costs by reusing as many processes and as much equipment as possible. This was achieved in the design for a new water-reclamation facility in Lawrence, Kan., which incorporates features that support initial liquid-stream and biosolids treatment requirements but allow relatively easy conversions and upgrades to meet potential tightening of effluent treatment criteria, as well as changes in biosolids final use within the plant’s life span.


VIEWPOINT

Funding Biosolids Projects
A losing battle?

Timothy G. Shea and Peter Burrowes

The Clean Water Act (CWA) was passed by the U.S. Congress in 1972, 2 years after the first Earth Day. Now, 35 years later under the same legislation, with federal and state construction grant program funds long since expended and a revolving loan fund providing a weak financing basis, there are still many CWA mandates to be met. However, with essentially no financial support from federal and state governments, the financial burden has fallen upon local governments to find the money to pay the bills.

What has happened to progress in wastewater treatment in the United States as funds have dried up? Will the same impacts also be seen elsewhere in the world after the first generation of collection systems and treatment works is completed? To put it simply, how sustainable are wastewater management programs anywhere without continuing support from the highest levels of government?


NEWS

Carbon Credit Where It’s Due
Industry experts explore the market for captured greenhouse gases generated by the wastewater industry

Biosolids already can provide nutrients for agriculture, groundcover for mined land, and a fuel source for energy-generating furnaces, but by taking advantage of carbon-credit trading, biosolids managers also might be able to turn their biosolids into additional funds.

Carbon credits are a financial commodity representing certified reductions in the emission or accumulation of greenhouse gases in the atmosphere, according to Environmental Credit Corp., a carbon-credit offset aggregation company.

“With wastewater and biosolids … [credits] could come from reducing energy use, replacing or displacing fossil-fuel energy with biomass energy or another type of renewable source, or directly reducing the emissions of methane or nitrous oxide at a facility,” said Scott Subler, ECC president. “It could potentially come from the use of biosolids in land-reclamation projects by sequestering carbon rather than letting it get back into the atmosphere.”


DEPARTMENTS

In Brief
Summaries of national and regional news items of interest to biosolids and residuals managers.


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