Surfactant foam injection for remediation of diesel-contaminated soil: A comprehensive study on the role of co-surfactant in foaming formulation enhancement.

Aqueous foam injection is a promising technique for in-situ remediation of soil and aquifers contaminated by petroleum products. However, the application efficiency is strongly hindered by foam's instability upon contact with hydrocarbons. Addressing this, we propose a new binary surfactant mixture of Sodium Dodecyl Sulfate (SDS) and Cocamidopropyl Hydroxysultaine (CAHS).

Aquifer recharge by stormwater infiltration basins: Hydrological and vadose zone characteristics control the impacts of basins on groundwater chemistry and microbiology.

Stormwater infiltration systems (SIS) are designed to collect and infiltrate urban stormwater runoff into the ground for flood risk mitigation and artificial aquifer recharge. Many studies have demonstrated that infiltration practices can impact groundwater chemistry and microbiology. However, quantitative assessments of the hydrogeological factors responsible of these changes remain scarce.

3D modelling of solute transport and mixing during managed aquifer recharge with an infiltration basin.

Artificial basins are used to recharge groundwater by many municipalities to improve the sustainability of storm water management. Despite its increasing operational implementation, artificial recharge still raises numerous questions related to its impact on groundwater quality. In this paper, a 3D numerical model of MAR basin/aquifer system was implemented in order to simulate the fate of water and pollutants.

Characterization and comparison of groundwater quality and redox conditions in the Arakawa Lowland and Musashino Upland, southern Kanto Plain of the Tokyo Metropolitan area, Japan.

Groundwater is essential for the Earth biosphere but is often contaminated by harmful chemical compounds due to both anthropogenic and natural causes. A key factor controlling the fate of harmful chemicals in groundwater is the reduction/oxidation (redox) conditions. The formation factors for the groundwater redox conditions are insufficiently understood.

Assessment of spatial representativity of X-ray tomography to study Vertical Flow Treatment wetlands.

French Vertical Flow (VF) treatment wetlands receive raw wastewater and provide simultaneous sludge and wastewater treatment. For proper sludge handling, the treatment wetland must be designed adequately and specific operational conditions must be maintained. When these conditions are not met, accumulation of biosolids may lead to clogging.

Assessment of X-ray Computed Tomography to characterize filtering media from Vertical Flow Treatment Wetlands at the pore scale.

Computed Tomography is a non-destructive technique often used in earth sciences for the description of porous media at the pore scale. This paper shows the feasibility of this technique to obtain 3D descriptions of filtering media in Vertical Flow Treatment Wetlands (VFTW). Three different samples from two full-scale VFTW were scanned.

Impact of both desiccation and exposure to an emergent skin pathogen on transepidermal water exchange in the palmate newt Lissotriton helveticus .

Amphibians are the vertebrate group most affected by global change. Their highly permeable skin is involved in maintaining homeostasis (e.g.

Liquid and gas permeabilities of unsaturated municipal solid waste under compression.

A novel set of experimental apparatus was designed and constructed to study the changes in the fluid-flow properties of municipal solid waste (MSW) related to the physical evolution of its structure under compression. The vertical liquid and gas permeabilities of MSW samples were measured in a laboratory-constructed cell termed an oedopermeameter. Another original device, a gas pycnometer, was employed to assess the volumetric gas content of the porous medium.

Effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: focus on the microbiology.

In an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in South African landfill sites. The overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests with immature compost and pine bark.

Characterisation of the physico-mechanical parameters of MSW.

Following the basics of soil mechanics, the physico-mechanical behaviour of municipal solid waste (MSW) can be defined through constitutive relationships which are expressed with respect to three physical parameters: the dry density, the porosity and the gravimetric liquid content. In order to take into account the complexity of MSW (grain size distribution and heterogeneity larger than for conventional soils), a special oedometer was designed to carry out laboratory experiments. This apparatus allowed a coupled measurement of physical parameters for MSW settlement under stress.

Alternative solutions for the bio-denitrification of landfill leachates using pine bark and compost.

Nitrified leachate may still require an additional bio-denitrification step, which occurs with the addition of often-expensive chemicals as carbon source. This study explores the applicability of low-cost carbon sources such as garden refuse compost and pine bark for the denitrification of high strength landfill leachates. The overall objective is to assess efficiency, kinetics and performance of the substrates in the removal of high nitrate concentrations.