Microbial fuel cells can be designed to remove nitrogenous compounds out of wastewater, but their performance is at present limited to 0.33 kg NO(3) (-)-Nm(-3) net cathode compartment (NCC) d(-1). By maintaining the pH in the cathode at 7.2, nitrogen removal was increased from 0.22 to 0.50 kg NO(3) (-)-Nm(-3) NCC d(-1). Bio-electrochemical active microorganisms seem to struggle with the deterioration of their own environment due to slow proton fluxes. Therefore, the results suggest that an appropriate pH adjustment strategy is necessary to allow a sustained and enhanced biological activity in bio-electrochemical systems.

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Perchlorate is widely used as a propellant in the aerospace and defense industries, and is of environmental concern due to its high mobility and inhibiting effect on thyroid function. An ideal treatment approach is bioreduction to chloride via dissimilatory perchlorate-reducing bacteria (PCRB). PCRB are ubiquitous in the environment, and are mainly facultative anaerobes and denitrifiers. Previous research suggests that PCRB may grow using a cathode as an electron donor, although this research was performed in a half cell with exogenous electron shuttles. We investigated a functioning MFC with a denitrifying biocathode for perchlorate reduction, as a means to confirm the existence of biocathode-utilizing PCRB and the possibility of perchlorate remediation without added shuttles. The biocathode was initially run with 20 mgN/L nitrate. The perchlorate concentration was increased stepwise from 0.1 mg/L to 20 mg/L, while the nitrate concentration was decreased from 20 mgN/L to 5 mgN/L. The maximum perchlorate removal was 12 mg/L-d, contributing 64% to the 0.28 mA produced by the cell. Given the lack of soluble electron donor in the medium, the extent of perchlorate reduction, and the improvement of perchlorate reduction over time, these tests strongly suggest PCRB are utilizing the cathode as an electron donor without exogenous electron shuttles.

Innovative wastewater treatment systems are needed for removing nutrients, noxious odors, dissolved organic matter, and pathogens from high strength agricultural and processing wastewater. A novel reciprocating subsurface-flow constructed wetland, consisting of four cells totaling 3570 m 2 (1.5 m deep), has been treating anaerobic lagoon wastewater from a commercial-scale confined swine feeding operation since November, 2000. The system, located near Aliceville, Alabama, has been monitored for twenty-one months. Hydraulic loading rates (HLR), from the anaerobic lagoon to the wetlands treatment system averaged 107 and 208 m 3 /day for years I and II respectively. Results to date indicate that the system's treatment efficacy is sustainable, with the exception of phosphorus removal. Doubling the flow temporarily reduced treatment efficacy with respect to monitored parameters. Average influent and effluent concentrations (ppm), of monitored parameters and their respective percentage removal rates were: CBOD 5 (521, 117, 78%); COD (1388, 393, 72%); NH 4-N (371, 51, 86%); and PO 4-P (52, 43, 17%). Electrical demand to operate reciprocating pumps, influent pumps and irrigation pumps averaged 203 kWh/day and 234.1 for the two wastewater loading rates respectively. Based on comments from farm workers and subjective laboratory testing, the system was effective in removing odors from lagoon effluent. Fecal coliform bacteria removal rates ranged from 2-3 Log reduction. In conclusion, the reciprocating wetland system was user friendly, relatively cost effective, and efficient with respect to removal of organic compounds, nitrogen, odor and fecal coliform bacteria. Further research will be required to enhance phosphorus removal.

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reviewed the profile and made invaluable comments. George Irani, Trade Analyst, and William Zangi, Trade Analyst of the Office of the Italian Trade Commissioner, Los Angeles, Calif., have patiently answered our questions and provided additional information on the Italian economy and commercial sector. Gianni Silvestrini, Visiting Researcher a t Lawrence-Livermore Laboratories, Berkeley, Calif., shared his knowledge of Italian solar research and development activities. Vittorio Jucker, Assistant Executive in Financial Matters, Azienda Generale Italiana dei Petroli (AGIP), New York, provided valuable information on ..the *Italian oil industry. John Kadyszewski, 'Associate Engineer, SERI's International Division, assisted in unit conversions and other technical matters. The staff of the Italian Embassy, Commercial Office, Washington, D.C., has provided socioeconomic and political information on a continuing basis.This document was prepared a s part of Task Number 4330, the Information Task of SERI's International Division, G. L. Case, :editor, in cooperation with the Solar Energy Information Data Bank (September 1980). The report is one of a series alid reflects the most thorough effort to gather information on solar energy activities in other countries. It cannot be considered inclusive and further information is welcomed.' It was prepared for the administrative use of the U.S. Department of Energy and is subject to frequent updating. For futher information contact SERI's International Division at (303) 231-1839.

We evaluated two microbial fuel cell (MFC) configurations that potentially can be used to remove BOD and total nitrogen from wastewater. The first was a two-chamber MFC with a denitrifying biocathode, where exoelectrogenic bacteria used the cathode as an electron donor and nitrate as the electron acceptor. This system could be used for tertiary denitrification of wastewater. Denitrification rates obtained in this system were 26 gN/m 3 -day, based on the cathode liquid volume, or 4.6 gN/m 2 -day, based on the estimated surface area of graphite granules in the cathode compartment. The biocathode revealed low microbial diversity and clear differences with the anode microbial community. The second was a plug flow configuration, where influent wastewater first passed through an anode compartment and then through a cathode compartment. This type of system could be retrofitted into an activated sludge tank. In the cathode compartment, nitrifying biofilms growing on air-filled hollow-fiber membranes (HFMs) were alternated with denitrifying biocathodes, accomplishing nitrification and denitrification. This configuration achieved a power density of 667mW/m 3 (11 mW/m 2 cathode). The nitrification fluxes were up to 1.1g NH 4 + -N/m 2 HFM/d, which is comparable to other hollow fiber membrane based processes, and denitrification fluxes were up to 0.5 g NO 3 --N/m 2 cathode/d. The results suggest that these MFC configurations may be suitable for removing BOD and TN from wastewater, concurrent with electricity production.