Reactive Blue 4 decolorization under mesophilic and thermophilic anaerobic treatments.

Anaerobic decolorization of anthraquinone dye represented by Reactive Blue 4 (RB4) was studied to evaluate the factors involved in dye-reducing behaviors such as dye concentration, co-substrate, treatment temperature, salt content, and dye-reducing microbial consortia. The experiment was conducted using digested sludge treated under mesophilic (35 degrees C) and thermophilic (55 degrees C) conditions. The results indicated that the thermophilic treatment gave higher potential for this dye decolorization compared with the mesophilic one. A reduced form of RB4 did not show an auto-oxidizing reaction but treated RB4 dye was shown in light yellow color, the intensity of which was related to the initial concentration of the dye used in the treatments. Starch, which showed similar decolorizing efficiency under thermophilic conditions, could be used as a co-substrate instead of glucose for the purpose of operating cost reduction. Due to the high content of salt contained in dye wastewater, the effect of salt (NaCl) was investigated. Results showed that decolorization could be accelerated with a concentration of NaCl lower than 200 mM, but the decolorization was inhibited by high concentrations of salt. The presence of RB4 inhibited methane productivity, while total organic carbon (TOC) reduction was similar to control, without dye addition. Increasing the temperature accelerated the decolorizing potential and TOC reduction. The evaluation of dye-reducing microbial consortia was done with acidogen and methanogen inhibitors which acidogenesis microorganism was dominant in RB4 decolorization.

Enhancement of oxygen transfer efficiency in diffused aeration systems using liquid-film-forming apparatus.

Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, liquid-film-forming apparatus is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for liquid-film-forming apparatus alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for liquid film aeration system increases by 37 % in comparison with conventional aeration system. Additionally, by tuning finely the structural parameters of the liquid-film-forming apparatus, it can also lead to high dissolved oxygen water with the dissolved oxygen percent saturation greater than 90 %. More importantly, this result is accomplished by simply offering a single-pass aeration at the depth as shallow as 26 cm. As a result, the objective of economical energy consumption in diffused aeration systems can be realized by lowering the aeration depth without sacrificing the aeration efficiency.

Improvement of oxygen transfer efficiency in aerated ponds using liquid-film-assisted approach.

In aerated ponds, oxygen is generally supplied through either diffused or mechanical aeration means. Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, a liquid-film-forming apparatus (LFFA) is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for LFFA alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for the liquid film aeration system increases by 37% in comparison with a conventional aeration system. Additionally, by tuning finely the structural parameters of the LFFA, it can also lead to high dissolved oxygen (DO) water with the DO percent saturation greater than 90%. More importantly, this result is accomplished by simply offering a single-pass aeration at a depth as shallow as 26 cm. As a result, the objective of economical energy consumption in aerated ponds can be realized by lowering the aeration depth without sacrificing the aeration efficiency. It is noteworthy that the data presented in this study are acquired either numerically or experimentally.

Resource recovery from excess sludge by subcritical water combined with magnesium ammonium phosphate process.

The amount of excess sludge produced in municipal wastewater treatment plants in Japan is increasing every year as the urban population increases. Phosphorus in excess sludge could be a potential phosphorus resource since at present, phosphate rock is being exhausted all over the world. Every year, Japan imports large quantities of phosphorus from abroad but much is discharged as excess sludge. Therefore, the solubilization process, one method of recovering phosphorus from sludge, could be a promising solution. In this study, a subcritical water process, a new technology that solubilizes sludge under subcritical conditions, was applied before the phosphorus in sludge was recovered with the magnesium ammonium phosphate (MAP) process. As a result, the solubilization rate of excess sludge achieved approximately 80% and about 94-97% of the phosphorus could be recovered.

Recycling mineral nutrients to farmland via compost application.

Increased cultivation of farmland has resulted in nutrient deficiency and consequently fertility degradation of soils. This research examined the application of composted wastes in terms of the feasibility and effectiveness of recycling plant essential minerals. Minerals in composts (derived from sewage sludge, livestock excrement, and municipal solid wastes, respectively) and in amended soils were observed. Ca/Mg ratios in amended soils and the effect of compost applications (mineral nutrients and heavy metals) on plant uptake were also studied. Results showed that composts, especially those made from sewage sludge and livestock excrement, were richer in mineral nutrients but also contained more heavy metals than untreated soil. The increase in some elements and plant-growth-essential Ca/Mg ratios were found in amended farmlands, implying that compost applications have made up for the nutrient deficiency and have adjusted chemical conditions of the soil. The soil contamination from heavy metals was noticeable. However, some results showed that the large existence of mineral nutrients and heavy metals in soils has caused no significant increase in the plant uptake of elements. The controlled composting process and farmland uses are believed necessary for reducing the heavy metal accumulation in agricultural plants.

Study on the potential of farmland soils as non-point sources of nitrogen and phosphorus in Japan.

The amounts of N and P accumulated in farmland soils of 50 cm depth were equivalent to the amount of chemical fertilizer supplied for 50-70 years. The values of N/P of surface soils in farmlands were 1.0-4.3, lower than expected. The median diameter of soil particles in run-off waters was generally less than 10 microm. The mean values of particulate fractions over 1 microm and over 0.22 microm were 19% for N, 27% for P, and 39% for N, 64% for P respectively. Fine particles of soil containing concentrated phosphorus should be carefully monitored as potential sources related to eutrophication.

On-site treatment of turbid river water using chitosan, a natural organic polymer coagulant.

Chitosan, acetylate of chitin, is a biodegradable cationic polymer. The objective of this study is to assess the applicability of chitosan as an on-site treatment agent of turbid water caused by river construction works and other diffused pollutions. The results of jar-tests indicate that floc of chitosan is much larger than that of aluminium sulfate, and turbidity treated by chitosan under moving water conditions is much lower than that of aluminium sulfate. Chitosan is applied to Imou River in Yamaguchi prefecture, where river construction work is going on. St.1 is located just below the construction work, St.2 is located about 250 m downstream from St.1, and St.3 is located about 350 m downstream from St.2. Initial turbidity of each station is 1,100, 937 and 313 NTU, respectively. By applying chitosan at St.1, turbidity of each station is drastically reduced to 1,100, 12 and 0 NTU. Chitosan could be helpful to reduce problems caused by turbidity in rivers.

Screening thermotolerant white-rot fungi for decolorization of wastewaters.

To select a thermotolerant fungal strain for decolorization of wastewaters, ligninolytic enzyme production (lignin peroxidase, manganese peroxidase [MnP], and laccase), decolorization, and removal of total phenol and chemical oxygen demand (COD) were detected. Thirty-eight fungal strains were studied for enzyme production at 35 and 43 degrees C on modified Kirk agar medium including 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and MnCl2. Thirteen strains grew on manganese-containing agar and provided green color on ABTS-containing agar plates under culture at 43 degrees C. Decolorization of wastewater from alcohol distillery (WAD) by these strains was compared under static culture at 43 degrees C, and Pycnoporus coccineus FPF 97091303 showed the highest potential. Thereafter, immobilized mycelia were compared with free mycelia for WAD decolorization under culture conditions of 43 degrees C and 100 rpm. The immobilized mycelia on polyurethane foam enhanced the ligninolytic enzyme production as well as total phenol and color removal. At about the same COD removal, MnP and laccase produced by immobilized mycelia were 2 and 19 times higher than by free mycelia; the simultaneous total phenol and color removal were 3.1 and 1.5 times higher than the latter. Moreover, decolorization of synthesis dye wastewater was carried out at 43 degrees C and 100 rpm. More than 80% of 300 mg/L of reactive blue-5 was decolorized by the immobilized mycelia within 1 to 2 d for four cycles.

Decolorization of alcohol distillery wastewater by thermotolerant white-rot fungi.

To detect thermotolerant fungus strain for decolorization of alcohol distillery wastewater (WAD), 38 fungus strains were studied. Ability of ligninolytic enzyme production was examined at 35 and 43 degrees C on agar media containing 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and MnCl2. At 43 degrees C, four of Pycnoporus coccineus strains showed their higher potential for WAD decolorization both on agar media and in liquid media. Immobilized mycelia on polyurethane foam removed total phenol about threefold higher than free mycelia did in shaking condition at 43 degrees C. Moreover, color removed by immobilized mycelia nearly 50% higher than free mycelia did.

Compost stability assessment using a secondary metabolite: geosmin.

Composting is a process involved not only in transformation of organic matter (OM), but also for transition of the microbial community. Microorganisms can directly provide important information on the stages and characteristics of composting. This paper was aimed at characterizing compost stability by a microbial secondary metabolite, geosmin, which is a volatile compound presenting an earthy smell. Since secondary metabolite production is dependent on the nutrient state of microorganisms, its production in association with physical and chemical parameters was monitored in the laboratory-scale and plant-scale composting processes. The results showed that the peaked geosmin liberation was consistent with stable state of composting indicated by the ambient temperature achieved, a slightly alkaline product and steady states of dissolved organic carbon (DOC), N and P contents and OM degradation in the laboratory-scale experiment. It was also in accordance with the stability identified by the facilities and CO2 respiration rate in the plant-scale composting. In addition, the production of geosmin was correlated with the C/N ratio for the solid sample. These results demonstrated that geosmin levels could be used as an index for the compost stability assessment in different composting processes with various organic solid wastes.

Distributions of iron, manganese, copper and zinc in various composts and amended soils.

A detailed observation was conducted on Fe, Mn, Cu and Zn in the composts derived from seafood processing by-product, garbage, swine manure and sewage sludge, respectively, as well as in amended farmlands. All elements were at lower levels of total contents but a higher percentage of water-soluble and exchangeable forms in composted seafood processing by-product and composted garbage than in composted swine manure and composted sewage sludge. Total contents increased in the order: composted seafood processing by-product approximately composted garbage < composted swine manure < composted sewage sludge. The applications of composted seafood processing by-product and composted garbage have neither caused Fe, Mn, Cu and Zn accumulation nor changed their distribution in soils; while the application of composted swine manure has largely increased Cu and Zn contents in soils, mainly in organic matter-bound form, and that of composted sewage sludge increased Mn, Cu and Zn in soils mainly in carbonate-bond and Fe-Mn oxides-bound ones. Fe is an exception, its total contents in soils decreased with the applications of composts except for composted garbage. Also, the rainfall and irrigation were another two main factors that affected available elements in soils.

Present state of food and feed cycle and accompanying issues around Japan.

Nitrogen (N) and phosphorus (P) cycles of food and feed, and the regulation systems for industrial wastewater are studied. The rate of domestic supply of food in Japan is 41% in 1970, 32% in 1990, and 29% in 1998 for N and 33%, 29%, and 28% for P, excluding grass feed. Among 3 countries, Japan, USA and Thailand, Japan is in the most difficult state to recycle food wastes to farmland. Comparing the estimated load of wastewater from food processing industries with the estimated load according to the budget study for N and P cycles, the tentative criteria of wastewater of food processing for P seem to be loose, and denitrification might be considered in every stage of N cycles. New regulation of industrial wastewater recently proposed in Japan may induce the chance for environmental business to remove N and P.

Modeling prediction of membrane bioreactor process with the concept of soluble microbial product.

The existence of soluble microbial products (SMP) produced by microbial cultures involved in biological wastewater treatment process has been widely investigated. This paper aims to establish an available mathematical model by incorporating the SMP concept into the Activated Sludge Model (ASM) No. 3. Prediction of sewage treatment performance in membrane bioreactor process under intermittent aerobic condition by model simulation was presented, and the results provided a more comprehensive image for this process. It was found that SMP could not be ignored and it contributed about 15% of total COD in the reactor under HRT = 12 hr and SRT = 10 days condition. The model also provided reasonable simulation results for nitrogen, biomass concentration, and other treatment behaviors. Furthermore, the treatment performance can be predicted under various operating conditions by this proposed model.

Monitoring of shallow sea environment by using snapping shrimps.

We examine the validity of pulse count of snapping shrimps for sea environmental monitoring. Snapping shrimps, which make a peculiar pulse sound, are found everywhere in the world. Pulse count can be achieved merely by recording their sounds for a few minutes by using a hydrophone without special biological knowledge. From field surveys and laboratory experiments, we found that the pulse count depends on water temperature when sea environment is normal, and it falls due to the occurrence of oxygen-deficient water. The results show that this method can be a useful index of the effect of water pollution on benthic animals in fixed-point observation.

A model for membrane bioreactor process based on the concept of formation and degradation of soluble microbial products.

A mathematical model of soluble microbial products (SMPs) formation-degradation was established based on the activated sludge model no. 1 and was applied to the membrane bioreactor process with high concentration of activated sludge under intermittent aerobic operational condition. The simulation results were in good agreement with the experimental data which indicated that the coefficients used in the model could successfully describe the treatment performance. The most advantage of this modified model over the conventional one was that the significant importance of SMP existence was demonstrated and the model provided an reasonable comprehension for SMP concept. The present study demonstrated that SMPs contributed most to the organic matter in the effluent, and the results coincided well with the observations of many other researchers.

A pilot-scale study of tertiary treatment of Jizhuangzi wastewater treatment plant by continuous preozonation-microflocculation-filtration process.

A pilot-scale study of tertiary wastewater treatment of the JIZHUANGZI Municipal Wastewater Treatment Plant was carried out by preozonation, coagulation and direct filtration process with the aim of producing wastewater suitable for reuse. The proposed treatment scheme could produce a filtered water with lower turbidity, COD(Cr) and colour at lower ozone and coagulant dosages. Ozone was added into the mixing tank with coagulant simultaneously and postozonation was not cost effective. With the increase of ozone dosage, better COD(Cr) and colour removals were observed especially at the ozone dosage between 0.7-1.0 mg l(-1). Similarly, increasing ferric sulphate dosage resulted in better removals of turbidity, COD(Cr) and colour in the filtered water. In contrast, increasing polymer T-80 dosage seemed to improve colour removal rather than turbidity and COD(Cr). To achieve removal efficiency of 70% for turbidity, 45% for COD(Cr) and over 60% for colour, the optimum dosages of ozone, ferric sulphate and polymer T-80 should be 0.7-1.0 mg l(-1), 10.0-12.5 mg l(-1) and 0.7-1.0 mg l(-1), respectively.

Effect of enforced aeration on in-vessel food waste composting.

A laboratory composting was conducted to determine the effect of the continuously enforced aeration on the composting performance. The mixture of dog food, excess sludge, and woodchip was used as raw composting materials. The temperature changes in the decomposition process, and pH, weight loss, ash, and extract composition from the final product after 17 days composting were investigated. The results demonstrated that flow rate of enforced aeration indeed influenced the composting performance. Composting under 0.05-0.1 1 min(-1) condition seemed better than that under 0.2-0.41 min(-1) condition. Higher flow rate of air not only cooled the composting mixture significantly, further adversely affected temperature rise, but also evaporated moisture mostly. Thermophilic composting can occur under 0.05-0.11 min(-1) air flow rate condition, while composting in cases of 0.2-0.4 l min(-1) air flow rate mainly resulted in a mesophilic process. Microbial activity was considered to be significantly inhibited at 0.4 1 min(-1) air flow rate condition based on the analyses of total organic carbon and volatile fatty acids from water extraction of composting products.

The entire nucleotide sequences of two distinct TT virus (TTV) isolates (TJN01 and TJN02) remotely related to the original TTV isolates.

TT virus (TTV) has a wide range of sequence divergence by which it is classified into at least 16 genotypes. A TTV isolate of genotype 12 (TJNO1) and another of genotype 13 (TJN02) were sequenced in the entire genome, and compared with the reported TTV isolates. TJN01 and TJN02 had genomic lengths of 3787 and 3794 nucleotides (nt), respectively, which were shorter by 66 and 59 nt than the prototype TTV isolate of genotype 1 (TA278). TJN01 and TJN02 shared the nucleotide sequence with TA278 merely in 53.9% and 55.2%, respectively. They possessed two major open reading frames (ORFs) and the noncoding region with a GC-rich region forming stem-loop structures, which are characteristic of TTV. However, their amino acid sequences in ORF1 were similar to that of TA278 in only 35.4 and 34.0%, respectively; TJN01 was 45.4% similar to TJN02. Comparison with TTV isolates of the same genotype identified hypervariable regions in ORF1 of TJN01 and TJN02, as in the prototype TTV of genotype 1. However, quasispecies were barely observed in them. Furthermore, sequences of hypervariable regions scarcely changed during 2-5.5 years in both TJN01 and TJN02. These results indicate that TTV of genotypes 12 and 13 are much different from the prototype TTV of genotype 1.

Significance of egg-jelly substances in the internal fertilization of the newt, Cynops pyrrhogaster.

Japanese newt, Cynops pyrrhogaster, undergoes internal fertilization as do most urodeles. In this study, we focused on the roles of egg-jelly in fertilization of C. pyrrhogaster and characterized the substances associated with those roles. When dry sperm were directly inseminated onto the egg, normal fertilization occurred without the presence of water. Egg-jelly extract (JE) prepared with Steinberg's salt solution contained the activity for the initiation of sperm motility. A substance of about 50 kDa in JE was significant for this activity; an inactive form of the substance probably exists in JE. Strong activity to induce acrosome reaction was detected in JE. It was inhibited by the treatment of JE with WGA, suggesting that carbohydrate in JE may be important for the induction of the acrosome reaction. This study suggests that two significant processes of fertilization are regulated by substances in the egg-jelly of the newt, C. pyrrhogaster.