Material and monetary flows of construction and demolition waste and assessment on physical and environmental properties of illegally dumped construction and demolition waste in Hanoi.

The main aim of this study is to investigate the material and monetary flows of CDW management and to characterize the distribution of illegally dumped CDW in Hanoi. Construction and demolition waste management has become a source of much concern to the urban authorities and citizens of big cities in Vietnam. It is estimated that 3000 t of CDW were generated per day from construction and demolition activities in Hanoi, but only 45% of the CDW was received at official landfills, while 55% of the CDW was disposed of elsewhere.

Current state of building demolition and potential for selective dismantling in Vietnam.

In Vietnam, an increase in construction activities together with the absence of recycling-oriented demolition techniques is giving rise to an alarming generation of construction and demolition waste. This study scrutinized the current state of building demolition approaches in Hanoi, Vietnam and evaluated the potential for the selective dismantling, or deconstruction, of reinforced-concrete (RC) houses. Site observations, direct measurement, and interviews were conducted to obtain information on technical, environmental, and economic characteristics of three residential housing sites, each representing a typical current demolition technique (manual, hybrid, and mechanical demolition).

Impact of diatomite addition on lead immobilization in air pollution control residues from a municipal solid waste incinerator.

Air pollution control (APC) residues, which are known to be the byproducts of incineration treatment, exhibit a high leaching potential of toxic metals. Calcium silicate hydrate (C-S-H), which is a major hydration product of hardened cement and immobilizes toxic metal, can be formed by the reaction of Ca with pozzolanic Si in a highly alkaline environment. Toxic metals might be immobilized by the addition of pozzolanic material to APC residues (instead of using cement), which is a Ca source and provides an alkaline condition.

Personality traits affect critical care nursing competence: A multicentre cross-sectional study.

Objective: To investigate the relationship between personality traits and critical care nursing competence among critical care nurses.

Research Methodology/design: Multicentre cross-sectional survey using a self-report questionnaire and path modelling, from August 2017 to December 2018.

Setting: Six intensive care units in Japan.

Waste generation, composition, and handling in building-related construction and demolition in Hanoi, Vietnam.

This study conducted a survey at 15 building construction and demolition sites in Hanoi, Vietnam in order to identify waste generation rates (WGR), composition, and current handling practices of construction and demolition waste (CDW). Waste quantification based on CDW layout, image analysis to identify CDW components, and face-to-face interviews with construction and demolition contractors to reveal CDW flows were performed. WGRs of 79.

Low fraction of methane in landfill gas emissions in an industrial waste landfill containing incineration ash and gypsum board waste under anaerobic conditions.

The behaviour of carbon dioxide (CO) and methane (CH) emissions at the surface and below the soil cover in an industrial waste landfill under anaerobic operating conditions was evaluated for six years. This landfill contained gypsum board waste and incineration ash - a practice currently allowed because of a change in Japanese regulations. The CO and CH fluxes decreased throughout the six years of the survey.

Long-term removals of organic micro-pollutants in reactive media of horizontal subsurface flow constructed wetland treating landfill leachate.

In this work, the removals of organic micro-pollutants (OMPs), i.e. DEP, DBP, 2,6-DTBP, BHT, and DEHP in sand, clay and iron powder mixed media of horizontal subsurface flow constructed wetland (HSSF) from landfill leachate were investigated over 3 years period.

Development of an easy-to-use questionnaire assessing critical care nursing competence in Japan: A cross-sectional study.

Background: Critical care nurses need a high level of medical competence, especially with regard to patient safety. There are several tools to measure general and critical care nursing competence, but the usability of these tools is inadequate because they include large numbers of questions. To maintain quality and safety in intensive care units (ICUs), it is necessary to be able to easily measure and evaluate critical care nursing competence.

The effectiveness of passive gas ventilation on methane emission reduction in a semi-aerobic test cell operated in the tropics.

Two landfill test cells, with and without gas vents, were used to investigate the effectiveness of passive aeration, through basal leachate pipes, in mitigating methane emissions from municipal solid waste disposal in the tropical climate of Thailand. Surface methane emission rate, as well as methane content in the landfill gas, were determined for a period of three years. The results indicate that the average methane emission rate from the test cell with passive gas vents (42.

Effect of increasing salinity on biogas production in waste landfills with leachate recirculation: A lab-scale model study.

The effects of salinity on anaerobic waste degradation and microbial communities were investigated, in order to propose an appropriate leachate recirculation process in a waste landfill in a tropical region. A salt concentration of 21 mS cm of electrical conductivity (EC) did not affect waste degradation, but a salt concentration of 35 mS cm of EC inhibited CH generation. A higher salt concentration of 80 mS cm of EC inhibited not only CH and CO generation, but also degradation of organic compounds.

Removal of heavy metals from synthetic landfill leachate in lab-scale vertical flow constructed wetlands.

Synthetic landfill leachate was treated using lab-scale vertical flow constructed wetlands (CWs) in sequencing batch modes to assess heavy metal removal efficiencies. The CWs filled with loamy soil and pumice stone were unplanted or planted with common reed (Phragmites australis) (Reed-CW) or common rush (Juncus effusus) (Rush-CW). Synthetic leachate contained acetate, propionate, humate, ammonium, and heavy metals.

Characterization of temporal variations in landfill gas components inside an open solid waste dump site in Sri Lanka.

Unlabelled: A long-term monitoring of composition of landfill gases in the region with high rainfall was conducted using an argon assay in order to discuss air intrusion into the dump site. Gas samples were taken from vertical gas monitoring pipes installed along transects at two sections (called new and old) of an abandoned waste dump site in Sri Lanka. NO concentrations varied especially widely, by more than three orders of magnitude (0.

Water reduction by constructed wetlands treating waste landfill leachate in a tropical region.

One of the key challenges in landfill leachate management is the prevention of environmental pollution by the overflow of untreated leachate. To evaluate the feasibility of constructed wetlands (CWs) for the treatment of waste landfill leachate in tropical regions, water reduction and pollutant removal by a CW subjected to different flow patterns (i.e.

Factors affecting the adsorptive removal of bisphenol A in landfill leachate by high silica Y-type zeolite.

Although bisphenol A (BPA), a representative endocrine-disrupting compound, has been detected frequently in landfill leachate, effective technologies for BPA removal from landfill leachates are limited. We used high silica Y-type zeolite (HSZ-385) for the selective adsorption of BPA from landfill leachate, and factors affecting this adsorption are discussed. Higher removal efficiencies at pH 5.

Microorganisms in landfill bioreactors for accelerated stabilization of solid wastes.

Landfill bioreactors (LBRs) with management of leachate and biogas have presented numerous advantages such as accelerated stabilization of solid wastes, reduced amount of leachate, and in situ leachate treatment. Such advantages have minimized environmental risks, have allowed extension of the useful life of the landfill site, and have fostered cost reduction. LBRs of three types have been developed using both anaerobic and aerobic modes: anaerobic, aerobic, and hybrid.

Characterization of microorganisms at different landfill depths using carbon-utilization patterns and 16S rRNA gene based T-RFLP.

A borehole core from 20 m depth of a Japanese landfill was characterized chemically and microbially. The borehole core sample was typically divided into 5 waste layers; 2.4-4.

Bioleaching of metal from municipal waste incineration fly ash using a mixed culture of sulfur-oxidizing and iron-oxidizing bacteria.

We investigated the behavior and characteristics of metal leaching from municipal solid waste incineration (MSWI) fly ash among pure cultures of a sulfur-oxidizing bacterium (SOB) and an iron-oxidizing bacterium (IOB) and a mixed culture. The IOB has a high metal-leaching ability, though its tolerability against the ash addition is low. The SOB might better tolerate an increase in ash addition than the IOB, though metal leaching ability of the SOB is limited.

The degradability of biodegradable plastics in aerobic and anaerobic waste landfill model reactors.

Degradabilities of four kinds of commercial biodegradable plastics (BPs), polyhydroxybutyrate and hydroxyvalerate (PHBV) plastic, polycaprolactone plastic (PCL), blend of starch and polyvinyl alcohol (SPVA) plastic and cellulose acetate (CA) plastic were investigated in waste landfill model reactors that were operated as anaerobically and aerobically. The application of forced aeration to the landfill reactor for supplying aerobic condition could potentially stimulate polymer-degrading microorganisms. However, the individual degradation behavior of BPs under the aerobic condition was completely different.