Leaching profile of per- and polyfluoroalkyl substances (PFAS) from biosolids after thickening, anaerobic digestion, and dewatering processes, and significance of protein, phosphorus, and selected ions.

Batch leaching experiments were conducted to evaluate the release of forty per- and polyfluoroalkyl substances (PFAS) from sludge samples collected after thickening, anaerobic digestion, and dewatering processes at two wastewater treatment plants. The South District wastewater treatment plant (SDWWTP), which receives domestic wastewater and landfill leachate from a nearby landfill, and the Central District wastewater treatment plant (CDWWTP), which receives only domestic wastewater, were selected for this study. PFAS released into the aqueous phase were analyzed by sacrificial sampling after 1, 3, 7, 14, and 30 days.

Characterization of oil exposure parameters affecting impact, recovery, and reestablishment of mangrove forests: Lessons learned.

The recovery and reestablishment times of mangrove forests exposed to oil are highly dependent on the oil type and oil-related contaminant levels in water and sediments, spill magnitude, oil exposure duration and frequency, duration of the oil contamination remaining in water and sediments, and post-spill events and clean up actions. Estimating the adverse effects of oil exposure and recovery times of mangrove forests is often done by referencing other spills in different geographical regions or locations with different coastal and environmental characteristics. As a result, these projections may not provide reliable estimates for recovery times and the success of the recovery efforts.

Classification of pores, water diffusivity and penetration characteristics of waste materials, and role of water as electron carrier in landfills: A review.

Coupling of biogeochemical processes occurs between different waste components and waste layers during decomposition of wastes materials deposited in landfills by mechanisms similar to those occurring in marine sediments (i.e., sediment batteries).

PFAS use in electronic products and exposure risks during handling and processing of e-waste: A review.

Poly- and perfluorinated alkyl substances (PFAS) have been and are used in electronic products due to their unique properties that improve product quality and performance. Ubiquities and persistence of some PFAS detected in environmental samples (water, soil, air) have attracted much attention and regulatory actions in recent years. This review provides an overview of PFAS use in electronic components; trends in quantities of e-waste generation; PFAS exposure pathways during e-waste handling and processing; reported PFAS in environmental samples and samples of serum, blood, and hair collected from people living near and working at e-waste processing sites.

Effects of saltwater intrusion and sea level rise on aging and corrosion rates of iron pipes in water distribution and wastewater collection systems in coastal areas.

Failure of water distribution and wastewater collection pipes can impact human health and environment due to potential contamination of water and soil in the surrounding areas, as well as service interruptions and road closures. This paper provides a quantitative assessment of projected shifts in failure rates of iron pipes due to saltwater intrusion and sea level rise in coastal areas. Probability of pipe failure depends on pipe characteristics, environmental parameters, and systems conditions.

PFAS risk propagation terminology in spatial and temporal scales: Risk intensification, risk attenuation, and risk amplification.

Poly- and per fluorinated alkyl substances (PFAS) are man-made chemicals that are used in many industrial applications to improve performance and durability of products. The CF bond is one of the strongest bonds in organic chemistry which makes PFAS highly persistent in the environment. Therefore, PFAS levels have increased in different environmental compartments (air, water, soil) at global scale over time since the early 1950s.

Materials and energy recovery from oily sludges removed from crude oil storage tanks (tank bottoms): A review of technologies.

Sludge and solids accumulating in crude oil storage tanks (referred as tank bottoms) reduces tank volume and requires periodic removal and disposal. Effective management of tank bottoms require considerations to reduce the toxicity of wastes and reduce potential environment impacts. This review compares alternative technologies for economical and environmentally beneficial management of oily sludges for recovery of hydrocarbons and energy with and without oil recovery.

Volatile organic contaminants (VOCs) emitted from sewer networks during wastewater collection and transport.

Presence of volatile organic compounds (VOCs) in sewer networks is a concern due to exposure of workers during maintenance at manholes and repairs of wastewater pipes, and hazard potential for gas explosion. Occurrence, types, and levels VOCs present at the wastewater treatment plant influents in municipalities in Florida (USA) were compared. Gas phase concentrations were estimated by the Henry's law.

Increasing gaps between materials demand and materials recycling rates: A historical perspective for evolution of consumer products and waste quantities.

Advancements in product design towards increasingly more compact and efficient systems have created challenges for recycling and materials recovery due to lack of appropriate infrastructure and mechanisms for collection as well as lack of appropriate materials recovery mechanisms and processes for discarded consumer goods. During the period from 1960 to 2015, the world population has increased from about 3 billion to over 6 billion. During the same period, the municipal solid waste quantities have more than doubled globally (from 1.

Managing siloxanes in biogas-to-energy facilities: Economic comparison of pre- vs post-combustion practices.

Siloxanes present in small concentrations in biogas interfere with the operation of biogas-to-energy facilities. During biogas combustion, siloxanes form white deposits on engine components (engine heads, spark plugs, valves) in crystals or amorphous forms depending on the temperature. The purpose of this study was to evaluate the economic feasibility of biogas-to-energy systems for managing the operational challenges due to siloxanes in biogas.

Removal of crude oil from highly contaminated natural surfaces with corexit dispersants.

Dispersants are used to reduce the impact of oil spills in marine environment. Experiments were conducted with natural materials which were contaminated by direct application of fresh Louisiana crude oil. The natural materials evaluated included sea sand (South Beach in Miami, Florida), red mangrove leaves (Rhizophora mangle), and sea shells (Donax variabili).

Persistence times of refractory materials in landfills: A review of rate limiting conditions by mass transfer and reaction kinetics.

Monitoring programs at closed landfills show that transformation of plastics, wood, and metals continue long after the active decomposition of the waste fractions are considered as complete. Studies conducted in natural anaerobic environments (e.g.

Odor impact zones around landfills: Delineation based on atmospheric conditions and land use characteristics.

Odors emitted from landfills can result in complaints by the residents living near the landfills. The aim of this study was to develop an assessment and delineation tool to identify the areas which can be impacted by the odors released from landfills based on land use characteristics and atmospheric conditions; and estimate the number of people who may be impacted. Odor emissions and dispersion analyses were conducted for three case study landfills under different atmospheric conditions in view of the land use characteristics around each landfill.

Classification of oil-particle interactions in aqueous environments: Aggregate types depending on state of oil and particle characteristics.

There are significant differences in the aggregation mechanisms and types of aggregates that form by oil-particle interactions in marine and laboratory environments depending on the state of oil (i.e., dissolved, emulsified, floating), size and type of particles involved (i.

Viscous effects on the interaction of granular particles with floating oils in water.

Light hydrophobic liquids (LHLs) can be submerged in water with granular particles by forming particle encapsulated liquid sacks. Formation and submergence of granular encapsulated LHL sacks can be an effective method for capturing and controlling the fate of floating oils. However, formation characteristics of the LHL sacks and effect of LHL viscosity on their behavior are not well understood.

Struvite formation and decomposition characteristics for ammonia and phosphorus recovery: A review of magnesium-ammonia-phosphate interactions.

Struvite (MgNHPO·6HO) forms in aqueous systems with high ammonia and phosphate concentrations. However, conditions that result into struvite formation are highly dependent on the ionic compositions, temperature, pH, and ion speciation characteristics. The primary ions involved in struvite formation have complex interactions and can form different crystals depending on the ionic levels, pH and temperature.

Morphology, composition and aggregation mechanisms of soft bioflocs in marine snow and activated sludge: A comparative review.

Conditions that lead to marine snow formation and aggregates that constitute the marine snow have similarities with the soft bioflocs that form during wastewater treatment by activated sludge process. Analysis of the conditions and similarities of the soft bioflocs in these two aquatic environments provide insight for the processes that lead to formation and growth of hydrated aggregates consisting of both living and nonliving particles, their chemical and biolocial composition, settling/suspension behavior, and contributing factors for their structure and morphology. This literature review provides a comparative analysis of the soft aggregates that form in marine and wastewater environments to characterize the conditions for formation and growth of highly hydrated aggregates consisting of microorganisms, suspended solids and large molecules.

Wicking of light hydrophobic liquid phase from water by pulverized rubber: Theoretical and experimental analyses.

Pulverized rubber (PR) can be utilized for capturing floating oils to prevent spreading and volatilization of hydrocarbons. Experiments were conducted using PR with four different particle sizes (ranging from 0.075 to 0.

From electronic consumer products to e-wastes: Global outlook, waste quantities, recycling challenges.

Advancements in technology, materials development, and manufacturing processes have changed the consumer products and composition of municipal solid waste (MSW) since 1960s. Increasing quantities of discarded consumer products remain a major challenge for recycling efforts, especially for discarded electronic products (also referred as e-waste). The growing demand for high tech products has increased the e-waste quantities and its cross boundary transport globally.

Self assembly, mobilization, and flotation of crude oil contaminated sand particles as granular shells on gas bubbles in water.

Contaminant fate and transport studies and models include transport mechanisms for colloidal particles and dissolved ions which can be easily moved with water currents. However, mobilization of much larger contaminated granular particles (i.e.

Selectivity and limitations of carbon sorption tubes for capturing siloxanes in biogas during field sampling.

Siloxane levels in biogas can jeopardize the warranties of the engines used at the biogas to energy facilities. The chemical structure of siloxanes consists of silicon and oxygen atoms, alternating in position, with hydrocarbon groups attached to the silicon side chain. Siloxanes can be either in cyclic (D) or linear (L) configuration and referred with a letter corresponding to their structure followed by a number corresponding to the number of silicon atoms present.

Partitioning of fresh crude oil between floating, dispersed and sediment phases: Effect of exposure order to dispersant and granular materials.

When three or more high and low energy substrates are mixed, wetting order can significantly affect the behavior of the mixture. We analyzed the phase distribution of fresh floating Louisiana crude oil into dispersed, settled and floating phases depending on the exposure sequence to Corexit 9500A (dispersant) and granular materials. In the experiments artificial sea water at salinity 34‰ was used.

Gravity induced densification of floating crude oil by granular materials: Effect of particle size and surface morphology.

Densification and sedimentation of floating crude oil to the bottom of water column reduces the radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. Performances of different natural granular materials were evaluated for capturing efficiency of floating fresh South Louisiana crude oil. The granular materials studied were quartz sand with medium (20-30mesh) and fine (40-100mesh) particle size, limestone with coarse (4-10mesh) and medium (16-40mesh) particle size, beach sand (20-80mesh), and clay (kaolin with ferric oxide; passing 200mesh).