Performance evaluation and effect of biogas circulation rate of a bubble column for biological desulfurization.

Biological desulfurization using a bubble column reactor was investigated in a continuous biogas treatment. Rapid biogas circulation between the digester and the bubble column for biological desulfurization was used to stimulate the gas-liquid mass transfer of H(2)S. A positive correlation between the biogas circulation rate and H(2)S removal rate was observed.

Extraction of raw sewage sludge containing iron phosphate for phosphorus recovery.

The objective of the present study was to establish an alkali extraction technology for FePO(4)-containing sewage sludge obtained from a wastewater treatment system that includes phosphorous removal by iron electrolysis. By clarifying the extraction properties of phosphorous, organic matter, and inorganic matter, conditions for alkali extraction were optimized. As a result, it was suggested that unheated phosphorous extraction would be superior for FePO(4)-containing sewage sludge.

Application of vibration milling for advanced wastewater treatment and excess sludge reduction.

As a new sludge reduction technology with a phosphorus removal mechanism, a vibration milling technology that uses iron balls have been applied to the wastewater treatment process. Three anaerobic-aerobic cyclic activated sludge processes: one without sludge disintegration; one disintegrated sludge by ozonation; and the other disintegrated sludge with the vibrating ball mill were compared. Ozonation achieved the best sludge reduction performance, but milling had the best phosphorus removal.

Effects of acute gamma-irradiation on community structure of the aquatic microbial microcosm.

To characterise indirect effects of ionising radiation on aquatic microbial communities, effects of acute gamma-irradiation were investigated in a microcosm consisting of populations of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.

Effect of hydraulic retention time on the hydrogen yield and population of Clostridium in hydrogen fermentation of glucose.

The conversion of glucose to hydrogen was evaluated using continuous stirred tank reactor at pH 5.5 with various hydraulic retention times (HRT) at 30 degrees C. Furthermore, the population dynamics of hydrogen-producing bacteria was surveyed by fluorescence in-situ hybridization using probe Clost IV targeting the genus Clostridium based on 16S rRNA.

Effects of acute gamma-irradiation on the aquatic microbial microcosm in comparison with chemicals.

Effects of acute gamma-irradiation were investigated in the aquatic microcosm consisting of green algae (Chlorella sp. and Scenedesmus sp.) and a blue-green alga (Tolypothrix sp.

Continuous H2 and CH4 production from high-solid food waste in the two-stage thermophilic fermentation process with the recirculation of digester sludge.

A thermophilic two-stage fermentation process using 10% total solids (TS) food waste was tested at varying organic loading rates (OLRs). The system was configured to produce H(2) and CH(4) in conjugation with the chemical oxygen demand (COD), nitrogen removal, and adjustment of the pH by returning sludge as an alkali buffer from the sludge storage tank for denitrification. The pH in the H(2) fermentation reactor was maintained in the range of 5.

Microbial diversity of anammox bacteria enriched from different types of seed sludge in an anaerobic continuous-feeding cultivation reactor.

Enrichment of anammox bacteria from three types of seed sludge, sewage, digester, and nitrification sludges, was conducted using a nonwoven fabric carrier for immobilizing the anammox bacteria, and the microbial diversity of the enriched anammox culture was investigated. About four months later, simultaneous removals of ammonium and nitrite, and production of a small amount of nitrate, which is unique to the anammox reaction, were observed in all 3 sludge reactors. Results of 16S rRNA gene analysis indicated that anammox bacteria were cultivated and diversified in each sludge type.

Measuring the effectiveness of a pilot scale bioreactor for removing Microcystis in an outdoor pond system.

A pilot scale fluidized bed bioreactor to control the cyanobacterium, Microcystis, was tested in an outdoor experimental pond system (28 m3) over a 57 day period. The pond system was inoculated with a wild bloom of Microcystis, and the bioreactor was preinoculated with an oligochaete, Aeolosoma hemprichi, which is known to prey on colonial Microcystis. This and other Microcystis predators such as the rotifer, Philodina erythrophthalma were observed to colonize the bioreactor during the experiment.

Phytoestrogens genistein and daidzin enhance the acetylcholinesterase activity of the rat pheochromocytoma cell line PC12 by binding to the estrogen receptor.

Some compounds derived from plants have been known to possess estrogenic properties and can thus alter the physiology of higher organisms. Genistein and daidzin are examples of these phytoestrogens, which have recently been the subject of extensive research. In this study, genistein and daidzin were found to enhance the acetylcholinesterase (AChE) activity of the rat neuronal cell line PC12 at concentrations as low as 0.

Seasonal effect on N2O formation in nitrification in constructed wetlands.

Constructed wetlands are considered to be important sources of nitrous oxide (N(2)O). In order to investigate the contribution of nitrification in N(2)O formation, some environmental factors, plant species and ammonia-oxidizing bacteria (AOB) in active layers have been compared. Vegetation cells indicated remarkable effect of seasons and different plant species on N(2)O emission and AOB amount.

Identification of the bacterial community involved in methane-dependent denitrification in activated sludge using DNA stable-isotope probing.

Methane is used as an alternative carbon source in the denitrification of wastewater lacking organic carbon sources because it is nontoxic and may be efficiently produced by anaerobic biological processes. Methane-dependent denitrification (MDD) in the presence of oxygen requires the co-occurrence of methanotrophy and denitrification. Activated sludge was incubated with 13C-labeled methane in either a nitrate-containing medium or a nitrate-free medium.

Nitrous oxide emission from polyculture constructed wetlands: effect of plant species.

Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N2O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N2O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared.

[Removal pathway and influence factors of hydroponic bio-filter method for nitrogen and phosphorus].

Study was made on the use of hydroponic bio-filter method (HBFM) for eutrophic surface water. Results show that HBFM can remove 16.8% of TN and 30.

RNA microarray for estimating relative abundance of 16S rRNA in microbial communities.

We developed an RNA microarray protocol in which total RNA from a microbial community was attached to a slide glass, and rRNA was detected by fluorescently labeled oligonucleotide probes. The RNA microarray requires only 4 h for hybridization and enables double staining and estimating relative abundance of rRNA.

Effect of plant harvest on methane emission from two constructed wetlands designed for the treatment of wastewater.

The emission of methane from two constructed wetlands [a free water surface flow system (FWS) and a subsurface flow system (SF)], constructed for the treatment of waste water, was evaluated at different sites inhabited by reeds (Phragmites communis), to test the effects of plant harvest. High methane emission was recorded immediately after harvesting in both wetlands. Several days after harvesting, the emission decreased in the FWS but remained high in the SF.

Highly sensitive real-time PCR assay for quantification of toxic cyanobacteria based on microcystin synthetase A gene.

The presence of cyanobacterial bloom in water supply reservoirs can cause potential health hazards. In this study, we aimed at the quantification of microcystin-producing cyanobacteria based on the microcystin synthetase A (mcyA) gene using real-time PCR. To perform a highly sensitive real-time PCR assay, the novel primer MSR-2R was designed and a coprecipitation DNA extraction method was used in this study.

Identification of acetate- or methanol-assimilating bacteria under nitrate-reducing conditions by stable-isotope probing.

Stable-isotope probing (SIP) was used to identify acetate- or methanol-assimilating bacteria under nitrate-reducing conditions in activated sludge. A sludge sample obtained from wastewater treatment systems was incubated in a denitrifying batch reactor fed with synthetic wastewater containing [(13)C]acetate or [(13)C]methanol as the main carbon source and nitrate as the electron acceptor. We analyzed how growth of bacterial populations was stimulated by acetate or methanol as the external carbon source in nitrogen-removal systems.

On site experiments of the slanted soil treatment systems for domestic gray water.

In order to make a breakthrough for the acute problem of water shortage in the world, the key words "decentralization and re-use" are very important for new sustainable sanitation systems that will be developed. Therefore, we focused on a new treatments system called "a slanted soil treatment system" which combines a biotoilet system with a domestic grey water treatment system. Because this system is a low cost and compact system, the system can be easily introduced to homes in urban areas or in the suburbs of cities in many developing countries.

Long-term monitoring of the succession of a microbial community in activated sludge from a circulation flush toilet as a closed system.

The microbial diversity and community succession of a circulation flush toilet were investigated by terminal restriction fragment length polymorphism and cloning analyses. Clonal libraries of 16S rRNA gene on day 3 and day 127 were constructed. On day 3, 102 clones were sequenced; Proteobacteria and Bacteroidetes accounted for 27% and 45%, respectively.

Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization (FISH).

A molecular biology method, fluorescent in situ hybridization (FISH), in which the pre-treatment was improved in allusion to the media of the constructed wetlands (CW), e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria (AOB) quantity and the relation with oxidation-reduction potential (ORP) in the Typha latifolia constructed wetlands under three different loadings in summer from May to September.

Development of an advanced biological treatment system applied to the removal of nitrogen and phosphorus using the sludge ceramics.

To develop a method of forming lake sediment into sludge ceramics with porosity and good biological adhesion for use as a medium for microorganisms in wastewater treatment, a study of the effects of forming conditions was conducted by adjusting the water content of sludge and compounding some additives. By adjusting the water content of the raw material at the kneading/pelletizing step to 40-42% and adding 3% waste glass to the raw materials to make up for the lack of flux, a sludge ceramic with a density in terms of specific gravity of saturated surface dry aggregate of about 1400 kg m(-3) was formed. In addition, to develop a small-scale wastewater treatment system capable of removing nitrogen and phosphorus, a sludge ceramic was applied as a medium for biological filtration.

Monitoring the microbial population dynamics at the start-up stage of wastewater treatment reactor by terminal restriction fragment length polymorphism analysis based on 16S rDNA and rRNA gene sequences.

The microbial population dynamics at the start-up stage of a wastewater treatment reactor was investigated using terminal restriction fragment length polymorphism (T-RFLP) analysis based on 16S rDNA and rRNA gene sequences. The results of fragment peaks suggested that the number and activity of nitrifying bacteria increased in association with the start of nitrification, and the relative ratios of 16S rRNA of these bacteria changed prior to those of the 16S rDNA. Furthermore, multidimensional scaling (MDS) analysis revealed that the 16S rRNA exhibited wider dispersion than the 16S rDNA at the start-up stage, indicating that the diversity of 16S rRNA in the microbial communities was strongly affected by environmental changes.

[Potential of nitrification and denitrification in water purification system with hydroponic bio-filter method].

The potential of nitrification and denitrification of sediment and the density of ammonium-oxidizing bacteria and nitrite-oxidizing bacteria in sediment in water quality purifying system with hydroponic bio-filter method (HBFM) were measured. The variation of nitrification and denitrification potential of the sediment along the stream way was quantitatively studied. The results show that among the sediments from front, middle and retral part of the stream way, the sediment from middle part reached a maximum nitrification potential .

Effects of organophosphorous pesticides used in china on various mammalian cells.

Organophosphorous pesticides are currently widely used in China to help boost agricultural production. However, these pesticides pose various threats to organisms, including humans, and are thus a cause of concern. Five organophosphorous pesticides, monocrotophos, omethoate, parathion-methyl, phoxim and dichlorvos, were examined for their effects on mammalian cell lines to determine their potential impact on physiological functions in vivo.