It is necessary to develop continually efficient methodologies and techniques for moderating risks to be within acceptable limits. After a brief background about risk analysis, a comprehensive view is presented about the methodologies and techniques for the same. Briefly discussed are the steps such as scope definition, hazard identification, knowledge integration, risk estimation, and computation of risk and its understanding including the role of qualitative and quantitative aspects of modeling for analyzing risk. Windstorm-induced damage due to natural hazards is highlighted. A case study on estimation of the roof damage in overall risk analysis of a roof structure against damage due to cyclonic winds is used for demonstrating knowledge and data integration.

Social progress and lifestyle change cause more people living in Taiwan to spend 90% of the daytime indoors. The indoor environment may affect human health and productivity. Results of previous researches reveal that inappropriate air conditioning design will cause air quality problems. The indoor ventilation pattern, which influences the indoor air quality and the thermal environment, is affected by the location of diffusers. This research is based on on-site testing and computer modeling of the air flow using a full-scale air conditioning system in a confined space to evaluate how the indoor air quality is affected. The results reveal that indoor temperature, humidity, air change per hour (ACH), and the diffuser arrangement will affect the indoor comfort and contaminant removal efficiency. When the rate of air exchange increases from 6 ACH to 12 ACH, the ventilation efficiency will increase by 30%.

A system with a combination of upflow anaerobic sludge blanket (UASB) reactor and constructed wetlands (CWs) has not yet been applied to river water polluted by both sewage and swine wastewater. In this study, a pilot system with a UASB reactor combined with two CW reactors was used to evaluate the feasibility of treating wastewater samples (mixture of sewage and partially treated swine wastewater). To observe the influence of hydraulic retention time (HRT) on the removal efficiency of various pollutants in the wastewater in the UASB reactor, two phases of experiments with HRTs of 6 and 2 h were conducted. The overall system performances between the two phases of experiments did not show obvious differences. The UASB reactor responded well in removing most of the pollutants observed except for ammonia nitrogen (AN) and total phosphorus (TP). The average removal efficiency could reach the levels of 93, 91, 86, 89, and 78% for suspended solids, ${\text{COD}}_S$ , ${\text{BOD}}_s$ , AN, and TP, respectively, with the UASB-CWs systems, which have potentials to be used to improve the water quality in river in practice.

Textile industry wastewater treatment is a cause for concern due to its intense color and high COD, which makes it difficult to treat it by conventional treatment options. Also, many of the dyes used in the industry fall under the category of hazardous wastes and are known to be toxic to microorganisms and aquatic life forms. An experimental study was conducted to observe the performance of Rotating Biological Contactor (RBC) system for color and COD removal from textile industry wastewaters. The RBC system could achieve up to $90\pm 5\mathrm{\%}$ removal of color and $95\pm 3\mathrm{\%}$ removal of COD in all four stages of RBC under optimum operating conditions. The first two stages of the RBC showed up to $75\pm 2\mathrm{\%}$ of color and $85\pm 2\mathrm{\%}$ of COD removal. The biofilm study concluded that a mixed culture of microorganisms (both bacteria as well as fungi) was responsible for the treatment of textile industry wastewater and the recovery of the RBC system could be very fast in case of any shock-loading occurred.

The hydration characteristics of ${\text{C}}_3\text{S}$ were studied in the presence of chromium (III) for up to 7 days. Chromium was introduced by either direct incorporation (as ${\text{Cr}}_2{\text{O}}_3$ ) during ${\text{C}}_3\text{S}$ preparation or during the subsequent hydration with a chromium $\left({\text{CrCl}}_3\right)$ solution. Levels of Cr(III) used were 1 and 3% by wt. of ${\text{C}}_3\text{S}$ . The chemically combined water content and free lime content were determined after 3 and 6 h and 1, 3, and 7 days of hydration. The results showed a retardation effect for the hydration of ${\text{C}}_3\text{S}$ in the presence of Cr, especially during the first hours of hydration. This retardation effect was more evident in ${\text{C}}_3\text{S}–\text{Cr}$ incorporated mixes than in ${\text{C}}_3\text{S}$ mixes hydrated in Cr-containing solutions. X-ray diffraction examination was performed on selected samples. The immobilization percentage of Cr(III) by ${\text{C}}_3\text{S}$ during hydration was determination by atomic absorption spectroscopy. A high degree of Cr immobilization (93.27–99.39%) was found after 7 days of hydration.

This research compares performances of an anaerobic two-phase reactor system and a conventional single-phase reactor system in treatment of a synthetic dye wastewater. The two-phase reactor setup used four anaerobic reactors based on upflow anaerobic sludge blanket technology as acid reactors and an expanded granular sludge bed (EGSB) reactor as a methane reactor. An anaerobic reactor based on EGSB technology constituted the single-phase reactor setup. The reactors were operated at different hydraulic retention times (HRTs). The acid reactors removed up to 67% of the influent chemical-oxygen demand (COD) and 77% of the influent dye or color. An average of 10–25% acidification was achieved, and acetic acid, propionic acid, and butyric acid were the major volatile fatty acids produced in the acid reactors. The organic loading or the influent dye concentration did not have any significant effect on acid production or its speciation. The two-phase system could be operated at a HRT as low as 7.5 h with at least 90 and 75% removal of COD and color, respectively. The single-phase system could remove only up to 50% of influent COD and color at a HRT of 9 h. The study, which spanned over a period of 450 days, concludes that a two-phase system produces a better quality of effluent in terms of color and COD than a single-phase anaerobic system when operated under similar conditions. However, the COD mass balance on the two-phase system showed a higher percent of unaccounted COD than the single-phase system.

Aluminum enters municipal solid waste (MSW) landfills from untreated raw curbside trash (MSW), industrial waste, and aluminum production wastes variously called dross, baghouse fines, salt cake, and other designations. Aluminum related reactions can arise and become problematic for landfill operations by generating undesirable heat, liquid leachate, and gases, such as hydrogen, hydrogen sulfide, carbon monoxide, and ammonia. Temperature excursions up to $\sim 150°\text{C}$ $\left(300°\text{F}\right)$ and landfill gas pressures exceeding 210 kPa have been observed. Water from the MSW, precipitation, injection, and/or surface water management can result in sufficient water to trigger problematic aluminum related reactions. Another source of water in a MSW landfill is leachate recirculation, which is not recommended if substantial aluminum is present in the landfill mass because it can lead to a problematic aluminum related reaction. This paper examines the chemical reactions involving aluminum in landfills and the negative consequences of introducing aluminum into MSW landfills regardless of its origin. Proposals for mitigating aluminum reactions are also presented.

The effects of cocontaminants, such as extractable organics and transformer oil (TO) on the remediation of polychlorinated biphenyl (PCB) impacted soils by hydrogen peroxide $\left({\text{H}}_2{\text{O}}_2\right)$ , have been investigated. Presence of transformer oil is found to adversely affect the PCB degradation. About 20 and 60% of Aroclor 1254 were remediated by 15 and 30% ${\text{H}}_2{\text{O}}_2$ , respectively, in soils which did not contain TO. When TO was introduced, no Aroclor 1254 degradation was observed with 15% ${\text{H}}_2{\text{O}}_2$ and a limited amount of about 20% of Aroclor 1254 degraded with 30% ${\text{H}}_2{\text{O}}_2$ treatment. The impact of cocontaminants on major Aroclor 1254 congeners 101, 87, 110, 118, 105, and 138 were also found to be limited in the presence of TO.