The effects of pipe materials on biofilm formation potential (BFP) and microbial communities in biofilms were analyzed. Pipe coupons made of six different materials (CU, copper; CP, chlorinated poly vinyl chloride; PB, polybutylene; PE, polyethylene; SS, stainless steel; ST, steel coated with zinc) were incubated in drinking water, mixed water (inoculated with 10% (v/v) of river water) and drinking water inoculated with Escherichia coli JM109 (E. coli), respectively. The highest BFPs were observed from steel pipes, SS and ST, while CU showed the lowest BFP values. Of the plastic materials, the BFP of CP in drinking water (96 pg ATP/cm(2)) and mixed water (183 pg ATP/cm(2)) were comparable to those of CU, but the other plastic materials, PB and PE, displayed relatively high BFP. The Number of E. coli in the drinking water inoculated with cultures of E. coli strain showed similar trends with BFP values of the pipe coupons incubated in drinking water and mixed water. Molecular analysis of microbial communities indicated the presence of alpha- and beta-proteobacteria, actinobacteria and bacteroidetes in biofilm on the pipe materials. However, the DGGE profile of bacterial 16S rDNA fragments showed significant differences among different materials, suggesting that the pipe materials affect not only BFP but also microbial diversity. Some plastic materials, such as CP, would be suitable for plumbing, particularly for drinking water distribution pipes, due to its low BFP and little microbial diversity in biofilm.

Abstract. Anthropogenic carbon is responsible for both global warming and ocean acidification. Efforts are underway to understand the role of ocean in a high CO2 world on a global context. However, marginal seas received little attention despite their significant contribution to biogeochemical cycles. Here we report the CO2 increase and ocean acidification in the surface waters of the Ulleung Basin (UB) of the East/Japan Sea, and possible causes are discussed. Fourteen observations of surface fCO2 were made in the period from 1995 to 2009. The contribution of temperature variation to the seasonality of fCO2 was almost equivalent to the non-thermal effect in the UB. However, the difference of relative contribution with the season makes two seasonal peaks of fCO2 in the surface water of the UB. Non-thermal effect contributed to the surface fCO2 drawdown in summer, whereas the surface fCO2 elevation in winter. The decadal trend of fCO2 increment was estimated by harmonic analysis. The estimated rates of increase of fCO2 were 1.8 ± 0.4 μatm yr−1 for the atmosphere and 2.7 ± 1.1 μatm yr−1 for the surface water. The ocean acidification trend, calculated from total alkalinity and fCO2, was estimated to be −0.03 ± 0.02 pH units decade−1. These rates seem to be higher than observations at most other ocean time-series sites during the same period of time. Sustained observations are required to understand more accurate trend in this area.

For simultaneous carbon and nitrogen removal via single stream, a microbial fuel cell (MFC) coupled with an aeration chamber and a bio-cathode was investigated. Without catalysts and any additional buffer, the MFC produced electricity continuously and the power density reached 1.3 W/m3 at a loading rate of 1.6 kg COD/m3 d. Simultaneously, the COD and the nitrate removal rate were 1.4 kg COD/m3 d and 67 g NO3-N/m3 d, respectively. When the hydraulic retention time was changed from 6 to 0.75 hours, the power density significantly increased from 0.2 to 10.8 W/m3 due to an increase of cathodic potential. When the aeration chamber was removed and the nitrate was injected into the cathode, the power density increased to 3.7 W/m3. At a high recirculation rate of 10 ml/min, the power density and the nitrate removal rate greatly increased to 34 W/m3 and 294 g NO3--N/m3 d, respectively.

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Since spent sulfidic caustic (SSC) produced from petrochemical industry contains a high concentration of alkalinity and sulfide, it was expected that SSC could be used as an electron donor for autotrophic denitrification. To investigate the nitrogen removal performance, a pilot scale Bardenpho process was operated. The total nitrogen removal efficiency increased as SSC dosage increased, and the highest efficiency was observed as 77.5% when SSC was injected into both anoxic tank (1) and (2). FISH analysis was also performed to shed light on the effect of SSC dosage on the distribution ratio of nitrifying bacteria and Thiobacillus denitrificans. FISH results indicated that the relative distribution ratio of ammonia-oxidizing bacteria, Nitrobacter spp., Nitrospira genus and Thiobacillus denitrificans to eubacteria varied little with the pH of the tanks, and SSC injection did not give harmful effect on nitrification efficiency. These results show that SSC can be applied as an electron donor of autotrophic denitrification to biological nitrogen removal process effectively, without any inhibitory effects to nitrifying bacteria and sulfur-utilizing denitrifying bacteria.