Average and 75 % biochemical oxygen demand (BOD) in the Yamato-gawa River, Japan, in 1963 were smaller than the criteria determined in 1970 (5 mg l⁻¹); however, they were deteriorated up to 22–32 mg l⁻¹ in 1970. The deterioration was caused by the population increase and economic and urban development. The national-level regulations on ambient water quality and pollutant discharge have been established in 1970. Municipal wastewater is the major contributor in pollutant discharges in the river basin. Estimated BOD discharge (PD(BOD)) in the river basin reduced to the level of 1963 in 2000; however, average and 75 % BOD were more than the criteria. Analysis on the relationship between BOD and PD(BOD) resulted in the five phases in 1963–2009. The equilibrium conditions changed from phase I to II because of the perturbation caused by the excess BOD discharge, self-correcting mechanisms were found in phase III, and equilibrium conditions changed from phase III to IV and V. The comparison of estimated BOD based on pollutant generation (PG) without measures and monitored BOD represented the following situations in 47 years: (1) It took several years before the effects of centralised WWTPs were observed, (2) PD(BOD) was less than 35 t-BOD day⁻¹ for the linear relationship of PD(BOD) and BOD, and (3) combined effects of wastewater treatment, river water purification facilities and soft measures were estimated to be about 10 mg-BOD l⁻¹ in 2010.

Aquaculture wastewaters, with oleic acid (C18:1 ω9) as the most representative contaminant fatty acid, were used as inoculum to perform enrichment cultures in mineral medium in the presence of oleic acid as the sole carbon and energy source, allowing isolation of four bacterial strains named DG1a, DG2a, DG1b and DG2b. 16S rRNA gene sequencing analysis assigned the four isolates to the species Pseudomonas aeruginosa. Among the isolates, P. aeruginosa strain DG2a showed degradation of fatty acids, including oleic acid (C18:1 ω9). The hydrophobicity features were investigated in strain DG2a, and a constitutive hydrophobicity in the bacterial cells was highlighted. The capability to produce biosurfactants by cells of the bacterial strain P. aeruginosa strain DG2a was evidenced both in the presence of oleic acid and of aquaculture wastewaters by revealing emulsifying activity, oil spreading tests, haemolytic and cetyltrimethylammonium bromide agar tests. Bacterial cultures containing raw biosurfactant were added to native wastewaters, showing a depletion of the oleic acid content. The use of the isolated bacterial strain P. aeruginosa strain DG2a and of the produced biosurfactant in bioremediation of aquaculture wastewaters is proposed, and the valorization of aquaculture wastewaters as raw material for biosurfactant production by using the isolate is moreover suggested.

Cr(VI) adsorption from aqueous solutions on peanut husk modified with formaldehyde (PeH-F) and peanut husk modified with formaldehyde and Fe (PeH-FFe) was evaluated as a function of shaking time, initial pH, chromium concentration, and temperature. Results showed that the Cr(VI) is preferentially adsorbed by PeH-FFe at pH 2 than pH 6. It also was found that the chromate equilibrium sorption capacity for PeH-FFe is at least six times higher than for PeH-F. The optimum pH to remove chromium is 2 for both materials; however, PeH-FFe has a higher efficiency for the chromium removal. Finally, Cr(VI) adsorption also depends on chromium concentration and temperature. The adsorption data as a function of concentration obey Linear, Freundlich, and Langmuir isotherms at pH 2 and 6. The Cr(VI) maximum capacity of PeH-FFe at pH 2 was 33.11 mg Cr(VI)/g, slightly higher than that at pH 6 (31.75 mg Cr(VI)/g). The linear isotherm shows that the pH affect the Cr(VI) distribution into the aqueous/solid phases. The negative value of ΔH and positive values of ΔG indicate that the chromium adsorption process is an exothermic and non-spontaneous process. The characterization of the peanut husk modified with formaldehyde and peanut husk modified with formaldehyde and Fe by scanning electron microscopy, Raman, and IR spectroscopies as well as the textural characteristics of the no-living biomasses were also considered in this work. © 2013 Springer Science+Business Media Dordrecht.

Two Co oxide catalysts supported on natural zeolites from Indonesia (INZ) and Australia (ANZ) were prepared and used to activate peroxymonosulphate for degradation of aqueous phenol. The two catalysts were characterized by several techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy (EDS) and N2 adsorption. It was found that Co/INZ and Co/ANZ are effective in activation of peroxymonosulphate to produce sulphate radicals for phenol degradation. Co/INZ and Co/ANZ could remove phenol up to 100 and 70 %, respectively, at the conditions of 25 ppm phenol (500 mL), 0.2 g catalyst, 1 g oxone and 25 C. Several parameters such as amount of catalyst loading, phenol concentration, oxidant concentration and temperature were found to be the key factors influencing phenol degradation. A pseudo first order would fit to phenol degradation kinetics, and the activation energies on Co/INZ and Co/ANZ were obtained as 52.4 and 61.3 kJ/mol, respectively. © 2013 Springer Science+Business Media Dordrecht.

A novel porous biomorph-genetic composite of α-Fe₂O₃/Fe₃O₄/C (PBGC-Fe/C) with eucalyptus wood template was prepared, characterized and tested for its sorption capacity of As(V) from aqueous solution. The result indicated that the PBGC-Fe/C material retained the hierarchical porous structure of eucalyptus wood with three different types of pores (widths 70∼120, 4.1∼6.4 and 0.1∼1.3 μm) originating from vessels, fibres and pits of the wood, respectively. Its surface area was measured to be 59.2 m²/g. With increasing initial As(V) concentration from 5 to 100 mg/L, the amounts of As(V) sorbed on the pulverized PBGC-Fe/C sorbent (<0.149 mm) increased from 0.50 to 4.01 mg/g at 25 °C, from 0.50 to 4.83 mg/g at 35 °C and from 0.50 to 4.19 mg/g at 45 °C, and the corresponding removal rates decreased from 99.97 to 40.10 % at 25 °C, 99.95 to 48.40 % at 35 °C and 99.92 to 42.05 % at 45 °C. At the initial concentrations of 5, 10 and 50 mg/L, the sorption capacities for the unpulverized PBGC-Fe/C sorbent (>3 mm) were determined to be 0.50, 0.99 and 2.49 mg/g, respectively, which exhibited a similar average value to those of fine particles or nanoparticles of iron oxides. The sorption could well be described by the pseudo-second-order kinetic equation. The equilibrium data were found to follow Freundlich as well as Langmuir isotherms.

The effects of six phosphate (P) fertilizers in mobilizing and immobilizing water-soluble lead (Pb) were determined in a contaminated soil (Alfisol from Shaoxing) from China and four Australian soils (an Oxisol from Twonsville Queensland and three South Australian soils from Cooke Plains (Typic Palexeralf)), Inman Valley (Vertisol), and Two Wells (Natric Palexeralf). The fertilizers tested were single superphosphate (SSP), triple superphosphate (TSP), monoammonium phosphate (MAP), diammonium phosphate (DAP), monocalcium phosphate (MCP), and dicalcium phosphate (DCP) to produce an initial P concentration of 1,000 mg/L. The Chinese soil contained 16,397 mg/kg total Pb, but the Australian soils were uncontaminated. The four Australian soils were each spiked with 1,000 mg Pb/kg soil (as Pb(NO3)2) and incubated for a month. Single superphosphate treatments decreased total soluble Pb in soil solution to 2-14 % of those of the nil-P (0P) treatment in the four Pb-spiked soils and to 48 % in the Chinese Pb-contaminated soil. The DAP treatment followed by the MAP treatment greatly increased the total soluble Pb in soil solution up to 135-500 % of the 0P treatment, except in the Two Wells soil. MCP could decrease the total soluble Pb in Cooke Plains, Inman Valley, Shaoxing, and Two Wells soils while increase it in the Queensland soil; DCP decreased the total soluble Pb in Cooke Plains and Queensland soils while increased it in the Shaoxing and Inman Valley soils. There were close relationships between the total soluble Pb, total soluble Al, and total soluble Fe in the water extracts of each. Soluble Al and Fe ions in soil solution increased soluble Pb concentrations. We conclude that not all phosphate fertilizers immobilize Pb in soils equally well. SSP and TSP are excellent Pb-immobilizing fertilizers, while MAP and DAP are strong Pb-mobilizing fertilizers. MCP and DCP are either Pb-immobilizing fertilizers or Pb-mobilizing fertilizers depending on their reactions with individual soils. © 2013 Springer Science+Business Media Dordrecht.

Nanoscaled Bi₂O₃ particles coated on ZnO nanorods (ZNRs) have been fabricated by combining hydrothermal technique with a chemical precipitation method. X-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV–vis absorption and photoluminescence studies were adapted to characterize the structure, morphologies, and optical properties of the nanocomposites. The results indicated that small Bi₂O₃ nanoparticles were well distributed on the surfaces of ZNRs. And the Bi₂O₃–ZNR nanocomposites showed high charge separation efficiency and •OH generation ability as evidenced by photoluminescence spectra. Under irradiation of a 55-W compact fluorescent lamp, the Bi₂O₃–ZNR nanocomposites demonstrated photocatalytic activities higher than pure ZNRs in the degradation of two endocrine-disrupting chemicals, phenol and methylparaben, which might be attributed to the high separation efficiency of photogenerated electron–hole pairs based on the cooperative role of Bi₂O₃ loading on ZNRs. Moreover, the Bi₂O₃–ZNR nanocomposite could be easily recovered and reused due to their one-dimensional nanostructural property. All these characteristics brought enormous benefits of Bi₂O₃–ZNR nanocomposites to the practical application in indoor environmental remediation.

Biowastes and inorganic additives are acknowledged efficient but site-dependent alternatives for in situ metal immobilization. The present study evaluates food waste-based compost, a particularly abundant type of biowaste in South Korea, and zeolite as amendments for increasing pH and reducing metal leaching potential in weathered tailings from an abandoned mine site. Two types of biowaste were used: food waste compost (60 % food waste and 40 % sawdust) and market compost (50 % food waste, 10 % agricultural waste, 10 % manure, and 30 % lime). Materials were thoroughly characterized. Leaching tests were then performed in reactors filled with various mixtures of organic–inorganic amended tailings, over a 4-week period. The in situ metal immobilization efficiency of compost was evaluated based on collected leachate quality. Results indicated that both organic and inorganic materials were successful for increasing pH (from 3.0 to up to 8.1) and metal immobilization, except for Pb and As, with which leaching potential increased in most amended reactors relative to un-amended tailings (up to 43 and 158 %, respectively). Over the duration of the experiment, the cumulative reduction of metal leaching potential ranked as follows: Zn (44–91 %) > Mn (4–76 %) > Cr (20–53 %) > Fe (34–44 %) > Cd (17–43 %) > Al (0.5–24 %). Among mixtures, combined biowaste and zeolite-amended tailings showed the best performance for increasing pH (7.5–8.1) and for metal immobilization. Chemical and biological processes, such as sorption and precipitation processes, were predominant. Overall, the study provides useful data on the efficient use of food waste compost for acid mine drainage prevention in South Korea.

We investigated the effects of four commercial formulations of herbicides (glyphosate [GLY], metsulfuron-methyl [MET], bispyribac-sodium [BIS], and picloram [PIC]) individually, and in three 50:50 mixtures (GLY–MET, GLY–BIS, GLY–PIC) on the common toad Rhinella arenarum (Anura: Bufonidae) tadpoles. Enzymatic parameters such as, glutathione S-transferase (GST), butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) activities, as well as erythrocyte nuclear abnormalities (ENA) were studied. Interactions between herbicides in mixtures were evaluated and classified as additive, synergistic, or antagonistic. Toxicity results (48-h LC₅₀) showed that PIC was the most toxic herbicide, followed by BIS, GLY, and MET, while GLY–PIC was the most toxic mixture, followed by GLY–BIS, and GLY–MET. All commercial herbicide formulations and their mixtures significantly inhibited BChE activity in exposed tadpoles. The AChE activity was also inhibited by all herbicides and their mixtures, except by GLY–BIS. The inhibition of GST activity was only significant for GLY, MET, PIC, and GLY–MET. A significant increase in the frequency of ENA was found for tadpoles exposed either to commercial herbicide formulations or to mixtures, except for GLY. All the mixtures showed synergism for BChE activity while for AChE only the GLY–MET and GLY–PIC mixtures acted synergistically. GLY–MET showed synergism for GST, whereas for ENA, the mixture GLY–BIS was antagonistic. This study with R. arenarum tadpoles demonstrates that the interactions between three of the most intensively used herbicides in soybean crops results in synergistic effects on mortality and neurotoxicity and synergistic or additive effects in genotoxicity.

The performance of the Purolite A847 weak basic anion exchanger in the simultaneous removal of the azo dye Lanasyn Navy M-DNL (LNCr) and the phthalocyanine dye Acid Blue 249 (CuPc) from acidic aqueous solutions was studied under dynamic conditions. The comparison of FTIR spectra of unloaded and dye-loaded anion exchangers made it possible to consider suitable sorption mechanisms. The results of dynamic experiments revealed that anion exchanger had a greater dynamic sorption capacity with a longer breakthrough time and a shorter length of mass transfer zone when both dyes LNCr and CuPc were removed from the one-component solution as compared to those of their mixture. Models of Wolborska and Juang were found to be suitable to predict the character of breakthrough curves and to determine the characteristic parameters of the Purolite A847 column useful for process design: the mass transfer coefficient β (1/min) and time at the break point τ (minutes). The result would be useful in the design of wastewater treatment plants for removal of azo and phthalocyanine dyes from aqueous solutions and water recycling.