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The purpose of this paper is to investigate changes in the environmental state of Pääsküla landfill in the post‐closedown period, especially changes in the soil and groundwater quality, composition of leachate water and air quality, and to analyse the effects of the works carried out and the measures implemented during the closing down of the Pääsküla landfill on the surrounding environment.

The study is based on the official environmental monitoring reports (EERC 2005‐2009) combined with the practical work experience and observations of the author on the landfill.

The study reveals that the most evident changes, which have taken place in the environmental state in the Pääsküla landfill were those in the quality of surface water. Remarkable improvement of the water quality of the Pääsküla River was detected after installation of the vinyl pile wall around the landfill body. After capping of the landfill, a drop in the content of methane in landfill gas was detected, as well as a decrease of the total gas production in the landfill.

The conclusions justify the efforts made in the course of closing down works of the Pääsküla landfill and the chosen technical solutions. It is necessary to continue the environmental monitoring of the landfill leachate water, ground water and surface water as well as monitoring of air quality and subsidences on the landfill.

The paper provides a detailed overview of the post‐closedown environmental monitoring and maintenance activities in the landfill as well as progress in the state of environment regarding the measures taken in order to decrease the negative environmental impact of the landfill. The experience of closing down the landfill can be used for similar projects, especially the impacts of capping the landfill on the methane production and installation of the protection wall and leachate collection drainage around the landfill on the suface water.

Local landfills in communities across the US are the battlegrounds in the conflict between our desire to consume goods at an extraordinary rate and our inability to deal with waste that is a by-product of this consumption. Despite efforts to reduce the amount of wastes generated through source reduction, in 2003, US residences, businesses, and institutions produced more than 236 million tons of municipal solid waste (trash and garbage), approximately 4.5 pounds of waste per person per day (EPA, 2003a). Also in 2003, 16,694 generators of regulated hazardous waste accounted for more than 30 million tons of hazardous wastes, more than half a pound of hazardous wastes per person per day (EPA, 2003b).

Explains the problems and opportunities created by the production of gas by decomposition in landfill sites. Describes the infrared and electrochemical methods by which gas can be detected and the typical manner in which these methods are applied. Also describes a PC‐controlled programmable sample system from Crowcon, which is designed for use in landfill sites.

Describes a passive, open‐path infrared gas detector that utilises thermal background radiation as the source. Explains its mode of operation, provides a specification and considers its route to market.

This review paper aims to focus on recent advances of carbon nanotubes (CNTs) to produce gas sensors. Gas sensors are widely used for monitoring hazardous gas leakages and emissions in the industry, households and other areas. For better safety and a healthy environment, it is highly desirable to have gas sensors with higher accuracy and enhanced sensing features.

In this review, the authors focus on recent contributions of CNTs to the technology for developing different types of gas sensors. The design, fabrication process and sensing mechanism of each gas sensor are summarized, together with their advantages and disadvantages.

Nowadays, CNTs are well-known materials which have attracted a significant amount of attention owing to their excellent electrical, electronic and mechanical properties. On exposure to various gases, their properties allow the detection of gases using different methods. Therefore, over recent years, researchers have developed several different types of gas sensors along with other types of sensors for temperature, strain, pressure, etc.

The main purpose of this review is to introduce CNTs as candidates for future research in the field of gas sensing applications and to focus on current technical challenges associated with CNT-based gas sensors.

The paper is an excerpt from a more comprehensive study by the Florida Department of Environmental Protection comparing the technical elements of offset projects in forestry, agriculture, and waste management, as well as some miscellaneous project types. The authors compare and contrast design elements of three specific offset projects: afforestation/reforestation, manure management, and landfill gas capture. The technical review for each offset project is concluded with a look at the potential applicability for that project in Florida in the context of the protocols evaluated.

Offset projects that may be employed in Florida are first broken up into comparable design elements specific to the selected offset project type. Focusing on the design elements, a discussion of the similarities and differences among the protocols for each offset project is presented. Each section begins with general findings then moves on to assessments of the detailed design elements. Finally, the project's general applicability to Florida is considered, highlighting specific strengths of particular protocols from the analysis of the design elements.

Protocols tend to vary from highly specific requirements to a more general set of recommendations. Interestingly, no one program's set of protocols is the most opportunistic for Florida, but rather various protocols may have distinctive strengths depending on the project type.

Many comparative studies of offset protocols evaluate protocols in the context of program‐level policies. This study uniquely values the technical details in the protocols and does not consider policy or program‐level issues.

Provides an overview of the current regulatory environment pertaining to the valuations of US landfill sites. Addresses changes in US regulations and how they relate to closure and post‐closure costs as well as the owners′ financial responsibility after closure. Concludes that the methodology of valuing landfills by using comparison of similar sales becomes less useful with the introduction of the new regulations.

The aim of this work is to compare quality of leachates from regional municipal landfill in different seasons (dry, snowy/rainy) during a three-year monitoring period due to the fact that quality of landfill leachate can rapidly change under different conditions.

Raw leachates were sampled prior to biological treatment at different periods of the year (November 2007, March 2008, May 2008, March 2009, and January 2010) to detect the changes in their composition due to different physico-chemical conditions at the site (temperature, moisture, etc.). Leachates were physico-chemically characterized and the toxicity of chosen leachates was assessed by a battery of biotests.

Most of the investigated raw leachates exceed Slovenian effluent limits. Samples from March 2008 and March 2009 generally showed higher concentration of measured parameters and also higher toxicity. It has been confirmed that the physico-chemical parameters of leachates usually decrease during rainy/snowy seasons, in addition to the change in toxicity.

This paper demonstrates the need to evaluate the physico-chemical parameters and toxicity of landfill leachate during different seasons of the year to achieve an appropriate assessment of its environmental impact.

Describes the author's work on the development of fibre sensors and networks for monitoring trace gases such as methane, acetylene, carbon dioxide, carbon monoxide, hydrogen sulphide and for detection of spills of gasoline, diesel and organic solvents, all of which are important in environmental and safety management. As an example, a 45‐point fibre optic sensor network has been installed on a landfill site to assess the distribution of methane generation across the site. System operation is based on near‐IR absorption and is currently being extended to monitor other gases such as carbon dioxide and hydrogen sulphide. Concurrently, research is being conducted on fibre lasers for the realisation of multi‐point, multi‐gas monitoring systems. Based on other principles (periodic micro‐bending loss effects), detection of hydrocarbon fuel spills has been demonstrated at multiple locations along the length of a specially designed fibre optic cable using standard optical time domain reflectometry (OTDR) measurements.

Financial assurance rules, also known as financial responsibility or bonding requirements, foster cost internalization by requiring potential polluters to demonstrate the financial resources necessary to compensate for environmental damage that may arise in the future. Accordingly, assurance is an important complement to liability rules, restoration obligations, and other regulatory compliance requirements. The paper reviews the need for assurance, given the prevalence of abandoned environmental obligations, and assesses the implementation of assurance rules in the United States. From the standpoint of both legal effectiveness and economic efficiency, assurance rules can be improved. On the whole, however, cost recovery, deterrence, and enforcement are significantly improved by the presence of existing assurance regulations.