Nitrification and denitrification processes occur simultaneously in aerobic wastewater biofilms. Although wide regions of the world have average temperatures of less than 15 °C for a half year, few studies have investigated the nitrogen removal by nitrification and denitrification in a single-stage aerobic biofilm reactor used for treating real wastewater under low-temperature conditions. This study showed successful wastewater treatment in a high average nitrogen removal rate of 78% at low water temperatures by simultaneous nitrification and denitrification in a rotating biological contactor (RBC) biofilm. Batch operations using the RBC to evaluate the rates of ammonium decrease at low temperatures demonstrated that the rate of ammonium decrease at 8 °C was 76% of that at 20 °C. Daily monitoring of nitrification and denitrification rates suggested that the denitrification rate was highly correlated with the nitrification rate. Next-generation sequencing (NGS) analysis revealed the presence of diverse and abundant denitrifying bacteria and aerobic bacteria in the RBC biofilm more than those in the activated sludge samples, which probably enabled the achievement of the high nitrogen removal rates at such low temperatures. Furthermore, correlation with the colony counts showed that the NGS analysis had the quantification range of three orders of magnitude (from 0.001% to 1%).

Bacillus species is an important microbial species in the activated sludge process. Some researchers reported that the predominance of Bacillus spp. improves treatment performance and good sludge settleability. The viable count of Bacillus spp. is usually measured by the plate culture method. Recently developed massive sequence technology has been applied to activated sludge samples; this technique provides more detailed information on its microbial community. However, the relationship between the number of Bacillus spp. and microbial compositions is not yet well understood. In order to elucidate this relationship, microbial community analyses based on 16S rRNA gene sequence and cell count of Bacillus spp. were conducted. Activated sludge samples, including those from conventional activated sludge, sequencing batch, and oxidation ditch processes, were collected and subjected to analysis. The results of microbial community analysis revealed that Proteobacteria and Bacteroides were the predominant bacterial phyla and overall community compositions resembled each other at the phylum level. The detection ratio for Bacillus spp. was 0-0.33%, and the number of Bacillus spp. ranged from 10 5 to more than 10 8 colonies/g-MLSS. The results showed that the number of Bacillus spp. and detection ratio showed a similar trend, and thus, these analyses could be complementary to each other.

A single basin biological denitrification system with alternative aeration is an excellent system which consists of simple components and performs flexible operation. Usually indirect parameters such as DO or ORP etc. have been used to control denitrification reactors. The authors tried to monitor NH4-N in a reactor by using a newly developed automated analyzer combined with UF sampler. Then the authors tried to control the operation of a denitrification reactor by using fuzzy inference. The fuzzy control system infers a suitable condition from multi variables (NH4-N, DO, ORP and pH) obtained in an actual process. The direct ammonium control system using fuzzy inference performed quick response and high nitrogen removal with stability and easy maintenance.

Summar yAn aerial application of neonicotinoid insecticide, thiacloprid, by a manned helicopter for controlling insect (Monochamus altermatus Hope) damage was carried out on pinewoods of Chikuma-city in Nagano Prefecture in June 2013. An investigation on thiacloprid drifts was conducted because many people reside near the applied area. Drifts in the air and in fallouts were collected at 4 locations near the applied area for three days after aerial spraying; and thiacloprid was quantified by liquid chromatography/tandem mass spectrometry. The result is that thiacloprid in the air was found from 4 locations at the maximum concentration of 1.9 ng/m 3 per day. Thiacloprid in fallouts was quantitatively detected from 3 locations at the maximum amount of 7900 ng/m 2 over three days. The maximum drift ratio was calculated to be 0.066 %. The results confirmed that a low-level drift occurred after the aerial application by a manned helicopter. The results suggest that the combination of air concentration measurements and fallout monitoring improved the evaluation of residential exposure to neonicotinoid insecticide.

The tubular type and plate-and-frame type are two conventional kinds of membrane modules used for collected human excreta treatment. However. such modules are hindered by high power consumption. blocking of the membrane by fiber components. the need for frequent cleaning and other such problems. Here, the authors investigated the performance and stability of a collected human excreta treatment plant utilizing rotary disk modules developed for the separation of highly concentrated liquid. As a result, it was found that, whether treating activated sludge or coagulated sludge, continuous operation over more than six months can be achieved at a low power consumption and without chemical cleaning. By this the authors have shown that rotary disk modules can be applied to the treatment of highly concentrated residential wastewater.