Virus Type-Specific Removal in a Full-Scale Membrane Bioreactor Treatment Process

We investigated removal of noroviruses, sapoviruses, and rotaviruses in a full-scale membrane bioreactor (MBR) plant by monitoring virus concentrations in wastewater samples during two gastroenteritis seasons and evaluating the adsorption of viruses to mixed liquor suspended solids (MLSS). Sapoviruses and rotaviruses were detected in 25% of MBR effluent samples with log reduction values of 3- and 2-logs in geometric mean concentrations, respectively, while noroviruses were detected in only 6% of the samples. We found that norovirus and sapovirus concentrations in the solid phase of mixed liquor samples were significantly higher than in the liquid phase (P < 0.01, t test), while the concentration of rotaviruses was similar in both phases. The efficiency of adsorption of the rotavirus G1P[8] strain to MLSS was significantly less than norovirus GI.1 and GII.4 and sapovirus GI.2 strains (P < 0.01, t test). Differences in the adsorption of viruses to MLSS may cause virus type-specific removal during the MBR treatment process as shown by this study.     

Metal mobilization from municipal solid waste incineration bottom ash through metal complexation with organic and inorganic ligands

As a first step in the development of ligand-assisted removal of heavy metals from municipal solid waste incineration bottom ash under alkaline conditions, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium oxalate, ammonium citrate, urea, and mixtures of ammonium salts and urea were examined to find which ligands could promote the leachability of elements, including heavy metals, and which elements could be mobilized through complexation. Ammonium citrate promoted the mobilization of Cr, Cu, Mn, P, Sb, and especially Fe. Ammonium nitrate accelerated Mg leachability significantly. Under the conditions used in this study, counter anions seemed to contribute mainly to the complexation. When a mixture of ammonium citrate and urea was utilized, a coexistence effect appeared on Fe mobilization. Although the correlation analysis of leaching test results showed a strong correlation among Cr, Cu, Fe, Mn, and P, X-ray diffraction analysis partially supported the correlation between Fe and Mn only.     

Impacts of natural weathering on the transformation/neoformation processes in landfilled MSWI bottom ash: a geoenvironmental perspective

Natural weathering processes are significant mechanisms that noticeably affect the fundamental nature of incineration ash residues. To provide a greater understanding of these processes, a MSWI (mono)landfill site in the north east of the US was selected as the target for systematic investigation of the natural weathering of bottom ash residues. Samples of various ages were collected from locations A (1 yr), B (10 yrs), C (13-14 yrs) and D (20 yrs) of the landfill in 2009. We investigated the phase transformation of the collected bottom ash particles, neoformation processes as well as the behavior and distribution of certain heavy metals (Cu, Pb, Zn, Ni, and Cr) in the neoformed phases using optical microscopy, SEM-EDX, and bulk examinations. Key findings: at the preliminary stage, the waste metallic particles (Al, Fe, and Cu) and unstable minerals such as lime, portlandite, ettringite and hydrocalumite convert to oxide and hydroxide (hydrate) phases, calcite, alumina gel and gypsum. At the intermediate stage, the decomposition of melt products including magnetite spinels and metallic inclusions is triggered due to the partial dissolution of the melt glass. At the longer time horizon it is possible to track the breakdown of the glass phase, the extensive formation of calcite and anhydrite, Al-hydrates and more stable Fe-hydrates all through the older ash deposits. Among the dominant secondary phases, we propose the following order based on their direct metal uptake capacity: Fe-hydrates>Al-hydrates>calcite. Calcite was found to be the least effective phase for the direct sorption of heavy metals. Based on overall findings, a model is proposed that demonstrates the general trend of ash weathering in the landfill.     

Analytical study on the suitability of using bentonite coated gravel as a landfill liner material

This study investigates the feasibility of using bentonite coated gravel (BCG) as a liner material for waste landfills. BCG has proven to be a very effective capping material/method for the remediation of contaminated sediments in aquatic environments. The concept of BCG is similar to that of peanuts/almonds covered with chocolate; each aggregate particle has been covered with the clayey material. Laboratory tests were aimed at evaluating regulated and non-regulated factors for liner materials, i.e., permeability and strength. Tests included X-ray diffraction, methylene blue absorption, compaction, free swelling, permeability, 1D consolidation, triaxial compression and cone penetration. The compactive efforts used for this study were the reduced Proctor, standard Proctor, intermediate Proctor, modified Proctor and super modified Proctor. The compactive energy corresponding to each effort, respectively, is as follows: 355.5, 592.3, 1196.3, 2693.3, and 5386.4 kJ/m(3). Results revealed that even though aggregate content represents 70% of the weight of the material, hydraulic conductivities as low as 6 x 10(-10)cm/s can be achieved when proper compactive efforts are used. Compressibility is very low for this material even at low (or no) compactive efforts. Results also demonstrated how higher compactive efforts can lower the permeability of BCG; however, over-compaction creates fractures in the aggregate core of BCG that could increase permeability. Moreover, higher compactive efforts create higher swelling pressures that could compromise the performance of a barrier constructed using BCG. As a result of this study, moderate compactive efforts, i.e., intermediate Proctor or modified Proctor, are recommended for constructing a BCG barrier. Using moderate compactive efforts, very low hydraulic conductivities, good workability and good trafficability are easily attainable.     

Organic acids and aldehydes in throughfall and dew in a Japanese pine forest

We analyzed low molecular weight organic acids and aldehydes in throughfall under pine forest, and organic acids in dew on chemically inert surfaces and pine needle surfaces at urban- and mountain-facing sites of pine forest in western Japan. Low molecular weight organic acids and aldehydes accounted for less than 5% of the dissolved organic carbon in throughfall at both sites. Formaldehyde at both sites and formate at the mountain-facing site were found at significantly lower concentrations in throughfall than in rainfall, which may be explained by the degradation and/or retention of these components by the pine canopy as the incident precipitation passed through it. The oxalate concentration in throughfall was significantly higher than those in rainfall at both sites, suggesting that oxalate was derived from leaching from the pine foliage. At both sites, organic acid concentrations were higher in dew on the pine needles than in throughfall or dew on chemically inert surfaces. This could be due to the long contact time of dew on pine needles, during which leached substances from pine needles and dry deposits accumulated on their surfaces can dissolve into the small volume of dew. The role of enhanced concentrations of oxalate in an aqueous phase on the plant surfaces (e.g., dew) is discussed in relation to hydroxyl radical formation via the photo-Fenton reaction.     

Time trend of hexabromocyclododecane in the breast milk of Japanese women

Hexabromocyclododecane (HBCD) is a type of brominated flame retardant. We investigated the time trend of the stereoisomer-specific concentrations of HBCD (alpha, beta, and gamma) in breast milk samples of Japanese women by using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pooled milk lipid samples collected in 1973, 1978, 1983, 1988, 1993, 1999, and from 2000 to 2006 were analysed. The concentration was below the detection limit in the samples collected between 1973 and 1983 and increased in those collected since 1988. Between 1988 and 2006, alpha-HBCD was detected in all 11 breast milk samples collected from 25 to 29-year-old Japanese women; gamma-HBCD, in 7; and beta-HBCD, in none of the samples. Time trend of summation operatorHBCD appeared to be related to that of the industrial HBCD consumption level in Japan.     

Detection of antibiotics in chicken eggs obtained from supermarkets in Ho Chi Minh City,Vietnam

The residual levels of antibiotics in Vietnamese eggs were monitored from 2014 to 2015. A total of 111 egg packages, distributed by 11 different companies, were collected from supermarkets in Ho Chi Minh City and the levels of 28 antibiotics were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening method. Sixteen samples tested positive for antibiotics; a total of eight compounds (enrofloxacin, ciprofloxacin, norfloxacin, sulfadimethoxine, sulfamethazine, sulfamonomethoxine, tilmicosin and trimethoprim) were detected. Enrofloxacin was detected in eight samples, with two samples exhibiting concentrations exceeding 1,000 µg kg^?1. Tilmicosin was detected in three samples at a range of 49–568 µg kg^?1. We observed that two of the 11 companies frequently sold antibiotic-contaminated eggs (detection rates of 56 and 60%), suggesting that a number of companies do not regulate the use of antibiotics in egg-laying hens. Our findings indicate that livestock farmers require instruction regarding antibiotic use and that continual antibiotic monitoring is essential in Vietnam.     

The weathering of municipal solid waste incineration bottom ash evaluated by some weathering indices for natural rock

The weathering of municipal solid waste incineration (MSWI) residues consists of complicated phenomena. This makes it difficult to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash, which was relevant interactively to pH neutralization and formation of secondary minerals. In this study, mineralogical weathering indices for natural rock profiles were applied to fresh/landfilled MSWI bottom ash to investigate the relation of these weathering indices to landfill time and leaching concentrations of component elements. Tested mineralogical weathering indices were Weathering Potential Index (WPI), Ruxton ratio (R), Weathering Index of Parker (WIP), Vogt’s Residual Index (V), Chemical Index of Alternation (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alternation (PIA), Silica–Titania Index (STI), Weathering Index of Miura (Wm), and Weatherability index of Hodder (Ks). Welch’s t-test accepted at 0.2% of significance level that all weathering indices could distinguish fresh and landfilled MSWI bottom ash. However, R and STI showed contrasted results for landfilled bottom ash to theoretical expectation. WPI, WIP, Wm, and Ks had good linearity with reclamation time of landfilled MSWI bottom ash. Therefore, these four indices might be applicable as an indicator to indentify fresh/weathered MSWI bottom ash and to estimate weathering time. Although WPI had weak correlation with leachate pH, other weathering indices had no significant correlation. In addition, all weathering indices could not explain leaching concentration of Al, Ca, Cu, and Zn quantitatively. Large difficulty to modify weathering indices correctly suggests that geochemical simulation including surface sorption, complexation with DOM, and other mechanisms seems to be the only way to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash.     

Air and landfill gas movement through passive gas vents installed in closed landfills

In a closed landfill, Japan, remedial actions have been undertaken to address the inadequate leachate collection and drainage systems. Part of this process included installing many passive gas vents in the landfill to promote stabilization of landfilled waste. This study focused on the gas velocity in vents by conducting tracer tests to elucidate the gas flow via passive gas vents. The gas composition and gas temperature in the vents was also measured.As the gas vents pass through the waste layer, both landfill gas and air flows through the vents. Therefore, passive gas vents can be used to aerate landfilled waste as well as to collect and release landfill gas. Aerobic biodegradation occurs when air migrates through the waste layer if organic matter is present; this increases the temperature of the waste layer. Inflow of air into the gas vents can occur at a wide range of depths, even 10–20 m below ground level. Air is induced not from the surface of the landfill, but horizontally along the waste layer. The driving force of air induction from outside is a buoyancy effect caused by the temperature rise due to aerobic biodegradation.     

Investigation of the self-heating and spontaneous ignition of refuse-derived fuel (RDF) during storage

Refuse-derived fuel (RDF)—RDF-5 according to ASTM guidelines—derived from municipal solid waste and other waste materials, has been prepared as a fuel source for power plants in Japan. RDF has been known as a stable and safe solid-fuel. However, some spontaneous ignition incidents occurred during storage of RDF in certain facilities. In the present study, the storage conditions, which might induce the spontaneous ignition in RDF samples, was investigated to understand and prevent this phenomenon. When the initial temperature of RDF sample was consistent, higher water content and shorter induction times was observed (e.g., the induction times of select RDF samples with 5.8% and 16.7% water content, was 446 and 270 min, respectively). Also, the induction time was affected by the size of a RDF sample. No relationship between bacterial fermentation and spontaneous ignition was observed. The linear relationship between the induction time and the inverse of the initial temperature of the RDF sample was obtained in the Arrhenius equation.