while improving the efficiency of a composting facility’s operation (namely, unsold product doesn’t build up onsite). It should be noted that the stigma surrounding the sales and marketing of biosolids-based products is often used as a reason (or excuse) for failure in marketing and sales. However, the truth is that the stigma surrounding biosolids can be managed, if done properly, by understanding the technical aspects of product usage and educating end users appropriately to address concerns. Further, there are well-understood methods of establishing successful marketing programs.

Important attributes of a successful program include producing a quality product, properly investing in a marketing program, and understanding the product and the market. Further, branding products and differentiating them in the marketplace can improve marketability and value.


Fresh Air in a Solids Processing Building
Air-ionized odor control bests traditional capture-and-treat systems in energy and operations and maintenance costs at Denver Metro

Dennis Tulenko

Polarized-air-ionizing hardware that produces positively and negatively charged oxygen molecules, or ions, has been successfully applied at wastewater facilities for odor control in Europe for more than 20 years. Operating systems in the United States now have a successful track record of more than 6 years. The ionized air effectively oxidizes most air contaminants, including hydrogen sulfide, ammonia, and other organic gases, and prevents the corrosion of electronics and equipment while saving energy.

The modular ionizers can be installed in ductwork on the fresh-air supply side of an existing or new ventilation system. Alternatively, small portable modules can be installed as self-contained recirculation units with a fan. Based on the performance data from the U.S. facilities using the technology, air ionization has been demonstrated to be a reliable, energy-saving solution for odor control. The system has a minimal footprint, low power requirements, zero water usage, and no chemical handling or storage. Both capital and operations and maintenance costs were less than for other options, such as wet scrubbers, activated carbon, and biological treatment.

At the 568,000-m³/d (150-mgd) Metro Wastewater Reclamation District in Denver, a 45,533-m³/h (26,796-ft³/min) fresh-ionized-air system has been completed for the solids processing building and a 28,388-m³/h (16,706-ft³/min) system for the cake storage building. The Metro air-ionization system uses 1680 W of power. This represents a total power savings of 98%, compared to a biofilter, costing the utility $883 per year for power and saving $48,523 annually.


A Clue in the Regrowth Mystery
How acetate-using bacteria may hold the key to odor issues in dewatered biosolids

Thomas Chapman and Steve Krugel

Anaerobic digestion of wastewater sludges relies on complex microbial communities for degradation of organic matter. The role of methanogens is important in maintaining the stability of the digestion process through the conversion of volatile fatty acids, especially acetate, to methane. Lab tests have indicated that when loading exceeds the capacity of methanogens, digester performance deteriorates and could lead to upset conditions. Preliminary work has found that the capacity of the methanogens to process substrate may be different for different facilities. Important operating factors include but are not necessarily limited to feeding frequency (such as whether it is continuous or limited to a number per day), solids retention time, hydraulic retention time, staging, solids loading, temperature, and solids degradability.

A laboratory method was used to measure the maximum acetate-utilization capacity, termed V_max, for several full-scale anaerobic digesters, and molecular methods were used to enumerate the concentrations of the acetate-utilizing methanogens Methanosaeta and Methanosarcina. Methanosaeta typically dominates mesophilic anaerobic digestion; however, Methanosarcina is capable of higher growth and acetate-utilization rates and confers greater stability to anaerobic digestion through its ability to better accommodate transient loadings, especially unexpectedly high loads. The plant evaluations showed that thermophilic digesters have greater ability than mesophilic digesters to process acetate, and some thermophilic digesters have a greater population of Methanosarcina than mesophilic digesters. Reviews of current findings also indicate that a strong methanogenic population in dewatered cake represses the generation of odors and fecal coliforms.


NEWS

Farm Bill Boosts Conservation Funding, Emphasizes Partnerships

Along with substantially increasing spending on conservation programs, the farm bill recently enacted by the U.S. Congress seeks to foster cooperation between farmers and local governments to improve water quality. Increased funding for projects intended to manage residuals from agriculture could be one result.

Formally titled the Food, Conservation, and Energy Act of 2008 (H.R. 6124), the legislation became law on June 18, after Congress overrode President George W. Bush’s veto of the bill. The $308 billion measure authorizes dozens of programs related to agriculture, nutrition, energy, rural development, trade, and research.

Overseen by the U.S. Department of Agriculture (USDA), the farm bill’s conservation programs largely provide financial incentives to farmers to conduct certain conservation measures or implement environmental management efforts on their lands. Compared to levels in the previous farm bill passed in 2002, the new bill increases total spending on conservation programs by $7.9 billion.

For water and wastewater agencies, the farm bill’s “most important” provisions concern its conservation programs, said Pat Sinicropi, legislative counsel for the Water Environment Federation. The programs “have a substantial water quality component,” she said.


DEPARTMENTS

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


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