Water resources are under pressure due to population growth, economic development, and changes in land use. This study aims to develop a hydrological method for calculating the water availability and evaluating the water supply demand capacity using the Index of Water Supply-Demand (IWSD), based on a case study of the Upper-Middle Ciliwung river basin in Indonesia. The two hydrological models used in this study were the National Rural Electric Cooperative Association (NRECA) and “FJ. Mock” models. The NRECA model was selected based on a statistical evaluation of correlation coefficients and the volume of errors. Based on the evaluation of business as usual and a reduction in water availability scenarios, the IWSD shows a value > 0, which means that the river can supply the necessary water for the economy, society, and environment. For other scenarios, with an increase in population growth and mix scenario, the IWSD shows values < 0, which means that the river cannot supply water for the users. The applications of the hydrological methods were developed in order to understand and seek solutions for decision makers in sustainable water resource management.

Sewage effluent plays an important role in regional water cycles and is gaining attention. Because a wide variety of chemicals are used in industry and daily life, the environmental impacts of trace chemicals in sewage effluents are a source of concern. Whole effluent toxicity (WET) testing uses biological responses to directly evaluate the toxicity of chemical substances in effluent. In contrast, the Japanese Pollutant Release and Transfer Register (PRTR) system provides estimated amounts of potentially hazardous chemicals released in effluent from factories and sewage treatment plants. The objectives of this study were to evaluate the ecological impacts of sewage effluent using WET tests and PRTR data and to compare the results from the two approaches. Of seven effluent samples tested, four demonstrated toxicities to aquatic organisms. Water analyses suggest that residual chlorine is responsible for toxicity to algae, while linear alkyl benzene sulfonates do not contribute to toxicity. The PRTR data tended to overestimate toxicity in comparison to the observed toxicity. The causes of this discrepancy are discussed, such as insufficient data. Due to the difference in calculation method, PRTR data of sewerage tends to be overestimated.

In this study, the water quality of typical acidified rivers in Yamagata and Fukushima Pref., Japan (Matsu River, Ara River and Su River) were investigated. These rivers have been receiving an inflow of a treated acid mine drainage leaches or an acidic hot spring water. Effects of dissolved aluminum and fluoride species on the acidified river environments were studied by data analyses on the water quality and chemical equilibrium calculations using the aqueous speciation computer code of the program PHREEQC. The results showed that aluminum ion in river water inhibits a rise in pH (i.e. a pH buffering effect) by alkali consumption with the hydrolysis in processes of aluminum solid-phase formations. The chemical equilibrium calculations indicated that the aluminum solid phases forming in the rivers would be mainly basaluminite (Al₄(OH)₁₀SO₄) and alunite (KAl₃(SO₄)₂(OH)₆) and generations of aluminum fluoride species such as AlF²⁺ and AlF₂⁺ at the points with fluorine loadings such as the inflow of hot spring water. Moreover, it was suggested that generations of these aluminum fluoride species would be moderating the pH buffering effects with aluminum solid-phase formations by moderation of the hydrolysis of aluminum.

Empty fruit bunch (EFB) is one of lignocellulosic wastes from palm oil mill. They are attractive feedstocks for production of fermentable sugars due to their low cost, renewable nature and abundance. Biological pretreatments employ microorganisms mainly fungi to reduce lignin and increase cellulose content prior to hydrolysis of cellulose into fermentable sugars. In this study, oleaginous fungi Aspergillus tubingensis TSIP9 with cellulolytic enzymes was used as potent microorganism for biological pretreatment of EFB through solid state fermentation (SoSF). The effluent from anaerobic digester (biogas effluent) was used as nutrient sources and moisturizing agents. After optimization in SoSF bioreactor, the cellulose content in EFB was increased from 40.58 ± 0.99% up to 61.24 ± 0.05% and this process also produced lipids of 115.8 ± 3.24 mg/g-EFB and cellulolytic enzymes of 20.00 ± 1.11 U/g-EFB. This study has shown that it was possible to biorefinery palm oil mill wastes into valuable cellulose pulp, microbial lipids and enzymes with the low-cost, practical and environmental friendly process.

From three different sewage treatment plants, three effluent samples were collected to demonstrate applicability of a non-targeted mass spectrometric analysis for exploration and identification of organic ecotoxicants in the samples. Five known organic ecotoxicants were added to these samples to simulate toxic samples. The non-targeted analyses of the simulated samples were conducted with a liquid chromatograph-high resolution mass spectrometer. The whole effluent toxicity tests were conducted by using Raphidocelis subcapitata as the test organism. The number of components detected by the analyses was 3,427. Relationships between peak volumes of these detected components and the samples’ toxicities were analyzed by the orthogonal projections to latent structure-regression analysis, the correlation analysis and the multiple regression analysis. An ion of m/z 286.9436 was found as a possible monoisotopic ion of the added toxicant. A molecular formula of the ion was determined by its accurate mass and natural isotopic pattern. The determined molecular formula was searched in an advanced mass spectral database. The database suggested that the found toxicant is triclosan (an antibacterial and antifungal agent). It was identified as triclosan by a co-chromatography using a reference standard reagent. Because a dominant toxicant was triclosan among the added five toxicants, the applicability was successfully demonstrated.

Wastewater treatment plays an important role in controlling the release of antimicrobial resistant bacteria to the environment. We characterized extended spectrum β-lactamase (ESBL)-producing Escherichia coli strains isolated from the environment by cefotaxime (CTX)-containing agar plates in this study. The results on the samples under the influence of treated wastewater showed that 1.2% to 5.3% of the total E. coli population formed colonies on the ECC medium containing 4 µg/mL CTX and all of them were ESBL-producing strains. Addition of 4 µg/mL CTX to the ECC medium imposed a selection pressure equivalent to MIC higher than 64 µg/mL (MIC breakpoint in the previous Clinical and Laboratory Standards Institute [CLSI] criteria) because the medium containing CTX not only inhibited the growth of the strains with lower MICs than the concentration in the medium but also suppressed the formation of colonies of the strains with higher MICs. Adding 64 µg/mL CTX in the ECC medium selected only clinically important strains with an intensively resistant spectrum covering cephalosporins (including ceftazidime) and fluoroquinolones. Some isolates harbored multiple ESBL-producing genes. The dominant genes encoding ESBL were bla_CTX-M group 1, bla_CTX-M group 9, and bla_TEM group.

Silver doped TiO₂-Millenium-PC500 (Ag/TiO₂-PC500) was prepared by wet chemical reduction method and characterized by X-ray diffraction, scanning electron microscopy, X-ray fluorescence, fourier transformed infrared and Brunauer-Emmett-Teller techniques. Ultraviolet (UV) and solar photocatalytic efficiency of Ag/TiO₂-PC500 for the removal of congo red (CR) and crystal violet (CV) from water was investigated. The influence of several operational parameters (photocatalyst, dye concentrations, pH, H₂O₂) was studied. Ag/TiO₂-PC500 exhibits better performance under UV and solar irradiations for the discoloration of CR as compared to TiO₂-PC500. In the presence of Ag/TiO₂-PC500, at free pH, CR was completely discolored within 15 min under UV (k = 0.064 min⁻¹) and solar irradiation (k = 0.207 min⁻¹). The discoloration rates of CV markedly improved under UV and solar irradiation, with Ag/TiO₂-PC500 as compared to TiO₂-PC500 albeit not complete (R ≤ 63.9%). Addition of H₂O₂ (0.01 mol L⁻¹) improved significantly the discoloration of CV (R ≤ 99.3%) with both photocatalysts whatever the light source. The better performance of Ag/TiO₂-PC500 (84.87 m² g⁻¹) as compared to TiO₂-PC500 (287.09 m² g⁻¹) confirms the positive contribution of silver during the photocatalytic process through its ability to absorb UV and solar light and slow the electron-hole (e⁻/h⁺) recombination. The COD measurements show moderate mineralization rates for both dyes independently of the irradiation source.