Sources of organic matter in first flush runoff from urban roadways.

This study aims to explore the influential sources of organic matter in first flush runoff from urban roadways by comparing organic carbon content and particle size distribution in road dust with those from discharge from vehicles during rainfall. Samples on first flush runoff and road dust were collected from urban roadways. In addition, vehicle drainage was assumed to flow from vehicles during rainfall events, so vehicle wash-off water was collected by spraying water onto the top and from the underside of vehicles to simulate accumulation during a vehicle run. In road dust, the organic carbon content in the <0.2 mm fraction was about twice that of the 0.2-2 mm fraction. The particle size distributions of both first flush runoff and vehicle wash-off water were similar, and particles <0.2 mm contributed to over 95% of the total volume. The dissolved organic carbon concentration in the vehicle wash-off water was considerably higher than that in the road dust/water mixture. The total organic carbon content in road dust was positively correlated with annual daily traffic. Therefore, vehicles were thought to strongly influence the nature of road dust.

In vitro synergistic effects of zoledronic acid and calcium on viability of human epithelial cells.

OBJECTIVE: Bisphosphonate-related osteonecrosis of the jaw is a common complication with defective wound healing of oral mucosa and frequently occurs in patients receiving zoledronic acid (ZA). The aim of this in vitro study was to investigate whether ZA has a cytotoxic effect at clinically relevant concentrations on epithelial cells when calcium conditions are altered. METHODS: HaCaT human keratinocyte cells were treated with ZA in the presence of various concentrations of calcium. The concentrations of ZA included submicromolar ones, which are comparable with those found in the plasma of patients. Cell viability and apoptosis were assessed using MTT assay and annexin V flow cytometry. RESULTS: Under standard culture conditions, cell growth was inhibited at 1 µM of ZA or above, but was unaffected by lower concentrations. However, when calcium concentrations were moderately increased, cell viability was decreased and apoptosis was induced at 0.2-0.3 µM of ZA. Moreover, a 50% reduction in serum in the hypercalcemic medium resulted in a significant decrease in cell viability at a much lower concentration (0.05 µM). CONCLUSION: These results suggest that clinically relevant concentrations of ZA, which alone have little effects, can be toxic to the epithelial cells depending on the conditions of extracellular calcium.

Removal of high concentration ammonia from wastewater by a combination of partial nitrification and anammox treatment.

Attached growth reactors were developed separately for solids retention time (SRT)-controlled partial nitrification and for anaerobic ammonia oxidation (Anammox) treatment, and a new nitrogen removal process is proposed for wastewater containing highly concentrated ammonia. For partial nitrification, an attached growth medium of polyurethane foam was used. Partial nitrification was achieved stably under a SRT of 4 days, and the abundance ratio of NO2(-)-N to the sum of NH4(+)-N, NO2(-)-N and NO3(-)-N was approximately 0.8 after 10 days. Under a SRT of4 days, the amoA gene concentrations of ammonia-oxidizing bacteria increased from 1 x 10(8) to 7 x 10(8) copies/l, whereas the 16S ribosomal RNA (16S rRNA) gene concentrations of nitrite-oxidizing bacteria did not increase. These results indicate that SRT-controlled operation is a promising technology for achieving partial nitrification. For the Anammox treatment, an attached growth medium of non-woven fabric was used. Inorganic nitrogen removal of approximately 80-90% was observed at an inorganic nitrogen loading rate of over 10 kgN/(m3-medium.d) and an influent nitrogen concentration of 400 mgN/l. Our non-woven fabric reactor showed similar or superior Anammox performance to that reported previously. By using a combination of these two rectors, we can develop a method that combines partial nitrification and Anammox treatment for effective and stable nitrogen removal.

Degradation characteristics of polylactide in thermophilic anaerobic digestion with hyperthermophilic solubilization condition.

To test whether hyperthermophilic treatment promotes polylactide (PLA) dissolution and methane conversion under anaerobic digestion conditions, a single thermophilic control reactor (55 °C) and a two-phase system consisting of a hyperthermophilic reactor (80 °C) and a thermophilic reactor (55 °C) were continuously fed with a mixture of PLA and artificial kitchen garbage. In Runs 1 and 2, the PLA dissolution ratios in the two-phase system were 79.2 ± 6.5% and 85.2 ± 7.0%, respectively, higher than those of the control. Batch experimental results indicated that hyperthermophilic treatment could promote PLA dissolution to a greater degree as compared with single thermophilic treatment and that ammonia addition also had a promotional effect on PLA dissolution. In the two-phase system, after hyperthermophilic treatment, dissolved PLA was converted to methane gas under the subsequent thermophilic condition.

Evaluation of a novel oxidation ditch system for biological nitrogen and phosphorus removal from domestic sewage.

A novel oxidation ditch system using anaerobic tanks and innovative dual dissolved oxygen (DO) control technology is proposed for biological nitrogen and phosphorus removal from domestic sewage. A continuous bench-scale experiment running for more than 300 days was performed to evaluate the system. Monitoring and controlling the airflow and recirculation flow rate independently using DO values at two points along the ditch permitted maintenance of aerobic and anoxic zone ratios of around 0.30 and 0.50, respectively. The ability to optimize aerobic and anoxic zone ratios using the dual DO control technology meant that a total nitrogen removal efficiency of 83.2-92.9% could be maintained. This remarkable nitrogen removal performance minimized the nitrate recycle to anaerobic tanks inhibiting the phosphorus release. Hence, the total phosphorus removal efficiency was also improved and ranged within 72.6-88.0%. These results demonstrated that stabilization of the aerobic and anoxic zone ratio by dual DO control technology not only resulted in a marked improvement of nitrogen removal, but it also enhanced phosphorus removal.

RO filtration of biologically treated textile and dyeing effluents using ozonation as a pre-treatment.

Bench-scale experiments were conducted to investigate the application of ozonation pre-treatment for biologically treated textile and dyeing wastewater to improve performance of the RO process. Based on ozonation experiments, four specific ozone consumptions (SOC), 0, 0.3, 0.6, 4.0 mg O3/mg DOC0 were chosen for study of the effects of ozonation on the reverse osmosis (RO) process. Membrane flux was recorded. Also, the permeate water quality parameters such as TOC, conductivity were analyzed. In addition, fouled membrane cleaning was studied. The study further examined the nature and mechanisms of membrane fouling using scanning electron microscopy (SEM) and the energy dispersive X-ray spectrometer (EDS). The effect of ozonation on RO filtration was found to depend on SOC. The study revealed that significant improvement can be achieved in the efficiency of RO filtration by employing ozonation with 0.6 mg O3/mg DOC0 SOC. Although the product water purity slightly decreased, the ozonation pre-treatment showed advantages at 0.6 mg O3/mg DOC0 SOC for the following: (i) mitigation of flux decline due to membrane fouling; (ii) improvement in foulants cleanability. In addition, hypotheses were put forward to explain the reasons from the aspect of organic matter characteristics changed by ozonation, such as changing on functional groups and molecular weight of organic matter.

Kinetic model of thermophilic L-lactate fermentation by Bacillus coagulans combined with real-time PCR quantification.

A simple L-lactate fermentation of organic wastes at pH 5.5 and 55 degrees C under nonsterile conditions using Bacillus coagulans can be suitable for L-lactate fermentation of garbage. A mathematical model that simulated the lactate fermentation characteristics of B. coagulans was developed by focusing on the inhibitory effects of substrate, lactate (product) and NaCl, and bacterial growth. Basic fermentation experiments were performed using simple substrates to derive fundamental parameters of growth rate and inhibition effects. The model was then applied to fermentations using simple substrates and artificial kitchen garbage in order to verify its applicability. Microbial concentration, a key state variable of the model was measured using both real-time polymerase chain reaction (PCR) and traditional methods. The results of these methods were compared for experimental cases in which only soluble substrates were used. B. coagulans concentrations were suitably measured using real-time PCR, even when traditional measurement methods for microbial concentrations cannot be used. The results indicate that the developed model and biomass measurement can be used to evaluate lactate fermentations using both simple and complex substrates. These proposed methods would be useful for developing a new bacterial function-based mathematical model for more complex acid fermentations.

Modeling of decomposition characteristics of estrogenic chemicals during ozonation.

The purposes of this study were to develop a refined model for simulation of ozonation of estrogenic chemicals under different conditions and to investigate the behaviors of estrogenic by-products using the model. In the cases of ozonation of 17-estradiol (E2), bisphenol-A (BPA) and nonylphenol (NP) in aqueous solution, it can be concluded that the liquid film resistances are larger than bulk resistances, and thus most of the reaction occurs in liquid bulk. E2, BPA and NP are easily decomposed producing by-products of ozonation, but the estrogenicity of these chemicals and the by-products reduced with increase in ozonation time. Through this research, ozonation was shown to be a promising method to decompose E2, BPA and NP and to reduce the estrogenicity of these chemicals.

The performance and microbial diversity of temperature-phased hyperthermophilic and thermophilic anaerobic digestion system fed with organic waste.

The objective of this study was to evaluate the performances and microbial diversities for development of the effective hyperthermophilic digester system that consists of a hyperthermophilic reactor and hyperthermophilic or thermophilic reactor in series. Lab-scale reactors were operated continuously fed with artificial kitchen garbage. The effect of temperature on the acidification step was firstly investigated. Results indicated that 20.8% of COD solubilization was achieved at 70 degrees C, with 12.6% at 80 degrees C. The average protein solubilization reached 31% at 80 degrees C. Methane conversion efficiency following the acidification was around 85% on average at 55 degrees C, but decreased with increasing temperature and methane gas was not produced over 73 degrees C. As well, bacteria affiliated with the methanogens dominated the population below 65 degrees C, while those affiliated with acidogens were predominant over 73 degrees C. These results indicated that the hyperthermophilic process has considerable benefits to treat wastewater or waste containing high concentration of protein.

Microbial population dynamics in a thermophilic methane digester fed with garbage.

The diversity of microbial communities in three full-scale thermophilic anaerobic digesters which treated garbage, sewage sludge and livestock wastes (hereafter called TGD, TSD and TLD, respectively) was investigated using 16S rDNA clone libraries in triplicate. The population dynamics of TGD were also studied. The purposes were to show the microbial diversity in each reactor and to suggest which key microbes in a thermophilic methane digester fed with garbage, including a check of reproducibility and the suggestion of an error range in this molecular biology method. 736 clones were identified, and the maximum error was estimated to be around +/-10% for the same OTU (operational taxonomic unit) and for most detected OTUs. The most frequently detected OTU shows a close relationship to Uncultured bacterium clone MBA08, Unidentified bacterium clone TUG22 and Uncultured archaeal symbiont PA204 in TGD, TSD and TLD, respectively. The microbial population dynamics in TGD were studied over a period of 90 days, and the occupying ratios of Bacillus infernus and Methanothermobacter wolfeii were shown to change with the change in VFA concentration. From the dynamic change and characteristics of the microbes, it is concluded that Bacillus infernus and Methanothermobacter wolfeii played an important role and were recommended as key microbes in TGD.

Effects of pH and temperature on products and bacterial community in L-lactate batch fermentation of garbage under unsterile condition.

Acidogenesis fermentation of artificial garbage without sterile condition was conducted in batch mode to investigate effects of cultivation pH (5.5, 6.0, 6.5) and temperature (45, 50, 55 degrees C). Bacteria exiting natively in the garbage were utilized in this study; in turn, no specific seed was inoculated. The results indicated that only one set of operational conditions (pH 5.5 and 55 degrees C) led to L-lactate fermentation. Obtained yield of lactate based on initial carbohydrate was around 0.5 and optical purity of L-lactate was around 99%. In this study, three typical cases, which were L-lactate, racemic lactate and butyrate fermentation, were observed depended on sets of cultivation pH and temperature. Microbial structures of typical cases were also identified with using 16S rDNA libraries. The analysis indicated that Bacillus coagulans produced L-lactate. Lactobacillus amylolyticus, which produces racemic lactate, and Clostridium thermopalmarium, which produces butyrate, were also detected on each typical sample. L. amylolyticus and C. thermopalmarium would be eliminated by setting cultivation temperature of 55 degrees C and above, and pH 5.5 and below, respectively. From a series of this study, operational conditions of pH 5.5 and temperature of 55 degrees C would be potentially suitable for L-lactate fermentation of garbage with view of efficiency and stability of its production.

Semi-continuous L-lactate fermentation of garbage without sterile condition and analysis of the microbial structure.

In order to develop a simple L-lactate fermentation of organic wastes, acidogenic fermentation was investigated in semi-continuous culture at 55 degrees C with using unsterilized artificial garbage as feedstock. And, sludge from a thermophilic acidification reactor was inoculated at the start of the fermentation. The effects of pH and hydraulic retention time (HRT) on performance of L-lactate production were discussed in a series of operational conditions with regard to long-term stability. The best operational conditions for L-lactate fermentation are proposed to be 55 degrees C, pH 6 and HRT of 10 days to get the highest yield of lactate based on initial carbohydrate in the feedstock. The yield of 0.74 and produced L-lactate optical purity of 96.7% were obtained on these operational conditions. Another L-lactate fermentation, which were semi-continuous and batch mode operations, were conducted to present reproducibility of the fermentation. Microbial structures in the semi-continuous fermentations were analyzed with using 16S rDNA libraries, and Bacillus coagulans was shown to be the most predominant species in the L-lactate fermented cultural broth.

Ozonation parameter for removal of oestrogenicity from secondary effluent without by-products.

The purposes of this study are to investigate ozonation characteristics, to evaluate oestrogenicity and to confirm behaviours of by-products during ozonation of secondary effluent. For the ozonation of secondary effluent, TOC was decreased only 10% when 4 (mgO3/mgC) of ozone consumption per initial TOC. However, UV254 and SUVA was decreased approximately 65% until ozone consumption of 2 (mgO3/mgC). Ozonation was also shown to be very effective for decrease of oestrogenicity in secondary effluent. Bromate ion started to form obviously when the ozone consumption per initial TOC exceeded 2 (mgO3/mgC) and increased while the time of ozonation became longer. From these results, ozone consumption per initial TOC was shown to be an appropriate operation parameter to reduce SUVA effectively and E2 equivalent concentration to less than 0.1 nM without significant formation of bromate ion, and its value was determined to be 2 (mgO3/mgC) in ozonation of secondary effluent.

Operation of a new sewage treatment process with technologies of excess sludge reduction and phosphorus recovery.

This paper shows the potential application of a new sewage treatment process with technologies of excess sludge reduction and phosphorus recovery. The process incorporated ozonation for excess sludge reduction and crystallisation process for phosphorus recovery to a conventional anaerobic/oxic (A/O) phosphorus removal process. A lab-scale continuous operation experiment was conducted with the ratio of sludge flow rate to ozonation tank of 1.1% of sewage inflow under 30 to 40 mgO3/gSS of ozone consumption and with sludge wasting ratio of 0.34% (one-fifth of a conventional A/O process). Throughout the operational experiment, a 60% reduction of excess sludge production was achieved in the new process. A biomass concentration of 2300 mg/L was maintained, and the accumulation of inactive biomass was not observed. The new process was estimated to give a phosphorus recovery degree of more than 70% as an advantage of excess sludge reduction. The slight increase in effluent COD was observed, but the process performance was maintained at a satisfactory level. These facts demonstrate an effectiveness of the new process for excess sludge reduction as well as for phosphorus recovery.

Application of biological activated carbon anaerobic reactor for treatment of hazardous chemicals.

An expanded-bed anaerobic reactor with granular activated carbon (GAC) medium has been developed to treat wastewaters that contain a high concentration of inhibitory and/or refractory organic compounds as well as readily degradable organic compounds. The process is characterised by a combination of two removal mechanisms; adsorption on GAC and biological degradation by microorganisms grown on GAC. Applicability of the reactor to treatment of phenol, chloroacetaldehyde (CAA), pentachlorophenol (PCP) and tetrachloroethylene (PCE) was discussed based on experimental data. All chemicals focused on here were removed well and stably at a removal efficiency of more than 98% even during starting operation and shock load operation. Chemicals in influent that exceeded biological degradation capacity was initially adsorbed on GAC and then gradually degraded, and hence the adsorptive capacity of GAC was regenerated biologically. These results proved that a biological activated carbon anaerobic reactor was effective for treatment of wastewater containing hazardous chemicals, especially for strongly absorbable chemicals, as well as readily degradable organic compounds at high concentration.

Control of bromate ion and brominated organic compounds formation during ozone/hydrogen peroxide treatment of secondary effluent.

Ozonation and ozone process combined with hydrogen peroxide have been identified as new technologies for direct or indirect reuse of wastewater. This study aims to establish appropriate conditions to control the formation of BrO3 and brominated organic compounds during O3/H2O2 treatment of secondary effluents of sewage. When the H2O2/O3 mole ratio of injection was above 0.5 and the DO3 concentration was below 0.1 mg/L, BrO3 was controlled as well as treatment purpose was completed. TOBr formation in O3/H2O2 treatment was also completely controlled.

Bacteriological study of autologous cryoprecipitate-derived fibrin glue as the operative sealant.

Fibrin glue (FG) is frequently used to seal and cover the anastomoses in many operations such as cardiovascular surgery or orthopaedic surgery. However, in case of gastrointestinal surgery, anastomoses are potentially contaminated, and FG may promote bacterial growth, increasing the risk of leakage. The purpose of this study was to examine the effect of cryoprecipitate-derived FG (CryoFG) on bacterial growth. Bacterial growth on the CryoFG and on the commercial FG (Beriplast P) was evaluated and compared with that on control medium. In addition, the complement activities were evaluated by heat inactivation or addition of guinea-pig complement to the experimental settings. The CryoFG inhibited the growth of Escherichia coli, whereas the commercial FG had no effect. Heat inactivation of the CryoFG inhibited the bactericidal effect of CryoFG. Addition of guinea-pig complement to the heat-inactivated CryoFG could almost restore the bactericidal activity, suggesting the important role of complement. This study showed that the CryoFG preserved the complement activity, which inhibited the in vitro growth of E. coli. Therefore, we concluded that the application of the CryoFG for gastrointestinal surgical anastomoses not only would be safe but also has the advantage of reducing bacterial infection.

Advanced sewage treatment process with excess sludge reduction and phosphorus recovery.

An advanced sewage treatment process has been developed, in which excess sludge reduction by ozonation and phosphorus recovery by crystallization process are incorporated to a conventional anaerobic/oxic (A/O) phosphorus removal process. The mathematical model was developed to describe the mass balance principal at a steady state of this process. Sludge ozonation experiments were carried out to investigate solubilization characteristics of sludge and change in microbial activity by using sludge cultured with feed of synthetic sewage under A/O process. Phosphorus was solubilized by ozonation as well as organics, and acid-hydrolyzable phosphorus (AHP) was the most part of solubilized phosphorus for phosphorus accumulating organisms (PAOs) containing sludge. At solubilization of 30%, around 70% of sludge was inactivated by ozonation. The results based on these studies indicated that the proposed process configuration has potential to reduce the excess sludge production as well as to recover phosphorus in usable forms. The system performance results show that this system is practical, in which 30% of solubilization degree was achieved by ozonation. In this study, 30% of solubilization was achieved at 30 mgO(3)/gSS of ozone consumption.

The effects of dissolved organic matter on the decomposition of di-n-butyl phthalate by ozone/hydrogen peroxide process.

The effects of the dissolved organic matter (DOM) on the ozone decay and the di-n-butyl phthalate (DBP) decomposition during ozone/hydrogen peroxide (O3/H2O2) process were investigated (DBP-d4 was used instead of DBP). Four surface waters, two secondary municipal sewage effluents (SMSEfs) and Suwannee river natural organic matter were used as DOM. The ozone decompositions in the DOM solutions were separated by instantaneous ozone consumption and slower ozone decay. The effect of H2O2 addition on the ozone decay was clearly observed at slower ozone decay. Ozone decomposition rate at slower ozone decay increased linearly with H2O2 dose. DBP-d4 was exponentially decreased with ozone consumption. Ozone consumption required to decompose 90% of DBP-d4 ((deltaO3)90%) in SMSEFs was higher than those in surface waters. The (deltaO3)90% per DOC of DOM values were from 22 to 23 micromole/mgC for SMSEFs and from 10 to 17 micromole/mgC for surface waters. The (deltaO3)90% values were correlated to specific ultraviolet absorbance at 254 nm (SUVA254) for surface waters.

Removal and recovery of phosphate and ammonium as struvite from supernatant in anaerobic digestion.

Removal of phosphorus and nitrogen is required to prevent eutrophication problems in lakes and enclosed coastal seas. And recovery of phosphorus from wastewater has been attracting attention because of lack in phosphorus resources in the near future. In this study, reaction kinetics and design parameters of struvite production are experimentally investigated by using basic reaction type and a draft-tube type reactors. Struvite production rate, which is a very important parameter in reactor design and efficiency estimation, is formulated in an equation consisting of a rate constant (k2), and magnesium, phosphate and ammonium concentrations. The value of k2 is shown to be increased with struvite concentration and mixing intensity in the reactor. The developed equation is applied to the results obtained from the draft-tube type reactor experiments and verified for its applicability. High struvite concentration of 10-25% is maintained in the draft-tube reactor experiments. 92% removal and recovery efficiency with effluent phosphorus concentration of 17 mg/L is achieved under the conditions of 4 minutes reaction time, pH of 8.5 and Mg/P molar ratio of 1.1.