Engineered nanoparticles in wastewater and wastewater sludge – Evidence and impacts

Nanotechnology has widespread application in agricultural, environmental and industrial sectors ranging from fabrication of molecular assemblies to microbial array chips. Despite the booming application of nanotechnology, there have been serious implications which are coming into light in the recent years within different environmental compartments, namely air, water and soil and its likely impact on the human health. Health and environmental effects of common metals and materials are well-known, however, when the metals and materials take the form of nanoparticles – consequential hazards based on shape and size are yet to be explored. The nanoparticles released from different nanomaterials used in our household and industrial commodities find their way through waste disposal routes into the wastewater treatment facilities and end up in wastewater sludge. Further escape of these nanoparticles into the effluent will contaminate the aquatic and soil environment. Hence, an understanding of the presence, behavior and impact of these nanoparticles in wastewater and wastewater sludge is necessary and timely. Despite the lack of sufficient literature, the present review attempts to link various compartmentalization aspects of the nanoparticles, their physical properties and toxicity in wastewater and wastewater sludge through simile drawn from other environmental streams.     

Biodegradability and compostability of polymers—test methods and criteria for evaluation

The treatment of solid waste in controlled composting facilities is an important possibility for reducing garbage. Natural and synthetic polymeric materials can be used for many purposes, for example, as packaging materials, where compostability is required. A prerequisite for official regulations and the decision as to which materials may be composted is investigations on their biodegradability and the quality of the compost produced. Several standardization groups at the ISO, CEN, and DIN are developing definitions, test methods, and classification systems for differentiating compostable from noncompostable materials. The concept which will be standardized and used in Germany is described in detail. It includes characterization of the test material, determination of the biodegradability using laboratory tests such as simple aquatic batch tests and a controlled aerobic composting test, investigation of the disintegration of the test material in industrial or bench-scale composting facilities, and finally, chemical and ecotoxicological analysis of the compost produced.     

Study of Trace and Heavy Metals in Rural and Urban Aerosols of Uludağ and Bursa (Turkey)

The concentrations of heavy, trace elements and major ions measuredin the Uluda and Bursa aerosols were investigated to assess size distributions, spatial and temporal variability, sources and source regions affecting the composition of aerosols in Uluda and Bursa. A total of 81 samples were collected in two sites, one in Bursa city and another in the Uluda Mountain during two sampling campaigns. Daily samples were collected using a high volume sampler on Whatman 41 cellulose filters in Uluda, while three days interval samples were collected in Bursa using an automatic dichotomous sampler on PTFE Teflon filters. Samples were analysed for 15 trace and heavy metals (Al, Fe, Ba, Na, Mg, K, Mn, Ca, Cu), (V, Pb, Cd, Cr, Ni, Zn), and 4 major ions (SO₄ ^2-, NO₃ ^-, Cl^-), (NH₄ ⁺) using ICP-AES, GFAAS, HPLC and UV/VIS Spectrophotometer,respectively. In general, concentrations of the metals measured inUluda aerosols were lower than those in Bursa. The concentrations of crustal elements were higher in summer than winter, while anthropogenic elements had higher concentrations in winter than summer. Most of the mass of crustal elements was concentrated in the coarse mode while the mass of the heavy metals was concentrated in the fine mode. Factor analysis revealed four factors with sources including crustal, industrial and combustion. Back trajectory calculations were used to determine long range contributions. These calculations showed that contributions were mostly from European countries, former Soviet Union countries, Black Sea and North Africa.     

Landfill leachate treatment with willows and poplars – Efficiency and plant response

Irrigation of willow and poplar short-rotation coppice with landfill leachate is an increasingly interesting treatment option. Minimal leaching to groundwater and disturbance to plant growth must be ensured, but in such systems, where various site-specific factors interact, a case-specific approach is needed to determine potential hazards. This paper compares the effect of leachate irrigation on willow grown in clay lysimeters and poplar grown in sand lysimeters. Leachate irrigation increased willow biomass production, but not that of poplar. Near-zero nitrate-N concentrations were found in drainage water for both species after 2 years of irrigation. Ability to retain total N and P, and TOC was relatively high for willow, taking into account the large amounts supplied, and better than for poplar. To reduce environmental risks the irrigation load should be reduced, but if leachate concentrations are reduced, the irrigation load can be as high as 6 mm/day.     

Australia's National Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances – Overview and Current Issues

Australia's National Plan to Combat Pollution of the Sea by Oil and Other Noxious and Hazardous Substances (the National Plan) has operated since 1973. The objectives of the National Plan are based on Australia's obligations as a signatory to the International Convention on Oil Pollution Preparedness, Response and Co-operation 1990 and a responsibility to protect natural and artificial (man made) environments from the adverse effects of oil pollution and minimise those effects where protection is not possible.The Australian Maritime Safety Authority (AMSA) is the managing agency of the National Plan, working together with the States and Northern Territory governments, other Commonwealth agencies, ports, and the shipping, oil and exploration industries, to maximise Australia's marine pollution response capability.The 1990s have been a period of significant change for oil spill response arrangements in Australia. The National Plan was extended in 1998 to cover chemical spills and is currently in the process of implementing the oil spill response incident control system (OSRICS). A fixed wing aerial dispersant spraying capability was implemented in 1996 and a research and development program has been put in place. The development of a computer-based National Oil Spill Response Atlas was a major project completed during 1999.     

Critical Loads and Exceedances of Acid Deposition and Associated Forest Growth in the Northern Hardwood and BorealConiferous Forests in Québec,Canada

We used the Québec forest monitoring network (`Réseaud'Étude et de Surveillance des Écosystèmes Forestiers' or RESEF)along with its atmospheric monitoring stations to assess criticalS and N loads and their combined soil acidification exceedancesfor natural ecosystems of the northern hardwood and borealconiferous forests in Québec, Canada. Critical loads (CL) forforest soil acidification were calculated using the simple mass-balance (SMB) approach and with the steady-state PROFILE model.Atmospheric deposition rates for water, S, N, Ca, Mg, Na, and K,for the years 1989–1993, and detailed, plot-specific forest andsoil characteristics were used as input. The SMB model alsorequired information regarding nutrient uptake and storage in theaboveground woody biomass. The CL calculations indicated that,from the 31 RESEF plots, 18 received atmospheric acidic inputs inexcess of their CL (55 and 61% of the hardwood and coniferousplots, respectively). The range of CL exceedance varied from 60to 470 eq ha^-1 yr^-1 for the hardwood stands, and from 10to 590 eq ha^-1 yr^-1 for the coniferous stands. The standswith CL exceedance were mainly located in the western and centralpart of the province. Stand growth associated with exceedanceclass of acidity was determined using the RESEF plots along withselected permanent forest survey plots having similar sitecharacteristics, but for which longer growth records wereavailable. We found a significant negative correlation betweenforest growth rates and critical soil acidification exceedancefor both the northern hardwood and the boreal conifer sites.Specifically, plots with critical load exceedances were found tohave a growth reduction of about 30% during the 1974–1982 andthe 1972–1990 measurement (plots with no soil acidificationexceedance served as a control). While this correlation is notnecessarily causal, it is nevertheless consistent with theexpectation that increased losses of soil base cations on accountof increased soil acidification should and could lead todeteriorating forest health conditions.     

Physical properties and biodegradability of blends containing poly(ε-caprolactone) and tropical starches

In order to assess feasibility of tropical starches (sago and cassava starches) as biodegradable plastic materials, blending with poly(-caprolactone) (PCL), a biodegradable polymer, was carried out. It was confirmed that the physical properties (tensile strength and elongation) of PCL/sago and PCL/cassava blends were similar to those of PCL/corn blend, suggesting that sago and cassava starches can also be blended with PCL for production of biodegradable plastic. However, the properties of all PCL/starch blends were still low compared with those of polyethylene. Enzymatic degradability evaluation showed that lipase degradation of PCL and-amylase degradation of starch increased as the starch content in the blend increased. Burial test of the blends for 1, 3, and 5 months was carried out and the rate of degradation of the PCL/sago blend was confirmed to be slower than those of PCL/corn and PCL/cassava blends. Observation of the film blends structure by scanning electron microscope revealed that the starch was dispersed in a PCL continuous phase. Furthermore, changes in the film surface before and after enyzme treatments were observed.     

Decoupling MSW settlement into mechanical and biochemical processes – Modelling and validation on large-scale setups

Forecasting settlements of non-hazardous waste is essential to ensure the integrity and durability of landfill covers over time. Over a short time span, the survey of settlements may also contribute to the investigation of the biodegradation processes. This paper addresses secondary settlements of Municipal Solid Waste (MSW), a heterogeneous and time-evolving material.An analysis of available experimental data from different pilots and the literature was conducted to quantify the influence of biodegradation on MSW secondary settlements. After making assumptions about the various features of the waste and their constitutive relationships, a one-dimensional biomechanical model to predict the secondary settlement has been developed. The determination of the total secondary settlement was obtained by the addition of two separate parts, the mechanical settlement, due to creep, and the biochemical settlement, due to the degradation of the organic matter. The latter has been evaluated based on the observed biogas production. Using the data from different recent large-scale experiments that provide a monitoring of biogas production, a method for predicting the biochemically-induced settlements is proposed and validated on these tests. The relative contributions of mechanical and biochemical settlements are also calculated and discussed as a function of waste pre-treatment and operation conditions (biological pre-treatment, shredding, leachate injection). Finally, settlement may be considered as a relevant indicator for the state of biodegradation.     

CHEMIFOG_V – A Model to Simulate Radiation Fogs and their Interaction with Vegetation and Chemistry

Radiation fog is an important modifier of atmosphericcompounds in the planetary boundary layer. In vegetated areas effects are especially pronounced due to the enlarged surface area. Besides affectingthe lower boundary of atmospheric models fog acts as amulti-phase reaction chamber leading to acid deposition. Here we present the 1-dimensional radiation fog modelCHEMIFOG_V to simulate regional radiation fogevents. The key feature of the fog model is thedetailed microphysics, where the aerosol/dropletspectrum is describedwith a joint 2-dimensional distribution, but also thedynamics, thermodynamics, and radiative transfer are calculated. Toinvestigate the interaction between fog and the biosphere amulti-layer vegetation module, including a soil module as well as a drydeposition module were coupled. Vegetation influences thedynamics, thermodynamics, and the radiation field of the lowestatmospheric layers. With CHEMIFOG_V, numerical case studieson dry and moist deposition processes on vegetation surfaces wereperformed. Hereby multi-phase chemistry and the processing of aerosolswere considered. The results show that the chemical composition of thedeposited fog droplets is mainly determined by the aerosol composition. Dry deposition fluxes are dependent on the incoming radiation and the leaves' surface conditions with respect to water coverage.Due to chemical aerosol processing and deposition, the aerosol spectrumis significantly modified in the planetary boundary layer.     

Gas and Aerosol Loadings at Holme Moss 1996–1998 Measurements and Analysis Using Back-Trajectory Clustering

A continuous two-year atmospheric datasetcomprising gas and aerosol loadings from amountain site in northern England (Holme Moss,W1°5130 N53°320) is presented. The data are analysed with respect to three-dayback-trajectories that are grouped according to aclustering technique that allows speed, directionand curvature of the airmass track to beconsidered. The technique is successful inseparating the data into chemically distinctsubsets. Up to 29% of the variance in the datais explained by back-trajectory clusters. Slow trajectories are associated with highloadings especially for the oxides of nitrogen,which may imply a local source for much of thesuspended pollutant. The data suggest thatproduction of nitrate and sulphate is limited byoxidant availability at least in the winter. Itmay be possible to optimise the analytical powerof the technique by increasing the importance ofrecent airmass track in determining clusterallocation. This applies especially to the totalsulphur loading.     

On Sand and Duststorms and Associated Significant Dustfall Observed in Chongju-Chongwon,Korea during 1997–2000

Monitoring of the occurrence of sandstorms and dustfallphenomena from 1997 to 2000 was carried out. We refer tosandstorms, duststorms and blowing sand as the phenomenaoccurring in the source region, while significant dustfall is thephenomenon that occur in the sink area. It was noted that while the sandstorms in deserts and loess in NW-N China and Mongolia occurred any time during the year while severe sandstorms occurred frequently from March to May after the springthaw. The wind erosion in the source region usually occurred withwind speeds greater than 8 ms^-1. However, severe sandstorm phenomenon occurred with wind greater than 15 ms^-1 for at least 3 hr or more. In the source regions, sandstorms occurred over60–120 days per year. In Mongolia, the observation of thenumber of sandstorm days decreased due to the increase in rainy days.When a dust cloud from a desert reached the sink region,significant dustfall in the Korean Peninsula occurred due tothe lack of strong winds. We defined the episode ofsignificant dustfall (SD) with the following values: TSP250, PM₁₀ 190 g m^-3 and visibility 6.5 km or less. In Korea, 8–12 episodes of SD occurred per yearwith 12 to 22 SD days. The maximum concentrations of TSP recorded were 989–1396 g m^-3 with PM₁₀ values of 861–996 g m^-3 and with the lowestvisibility of 1.4–1.6 km.     

Photo-/Bio-degradability of Agro Waste and Ethylene–Propylene Copolymers Composites Under Abiotic and Biotic Environments

Composites were prepared by two methods, (i) graft copolymerization (GFC) of isotactic polypropylene (PP) with maliec anhydride, (MAH) followed by esterification with coir fiber and (ii) by direct reactive mixing (DFC) of polypropylene (PP) and ethylene–propylene (EP) copolymers with MAH and peroxide with coir fiber. These composites, after molding in films (5×5 cm, m thickness) were examined for susceptibility to biological attack by measuring the percentage weight loss in compost upto 6 months, periodically, and fungal colonization on surface of the samples, when kept as sole carbon source for the growth of Aspergillus niger in culture medium upto 40 days. Photodegradation was evaluated by monitoring the variations in FT-IR spectrum and crack formation after successive treatment with UV light (≥290 nm) for 0, 20, 50 and 100 h at 60°C in the presence of air. Specimens of virgin PP were taken as a reference during all period of photo and biodegradation studies. Significant changes were observed depending on the preparation methods during photodegradation and biodisintegration of composites. DFCs samples were disintegrated faster than GFCs during the composting whereas, in culture, GFCs were covered highly in well uniform way by fungi. It was observed that photo-oxidative ageing directly enhanced the biodegradability of composites as the increase in fungal growth rate and decrease in weight during composting were found. It was concluded that extent of compatibilization had a profound effect on photo-oxidation and biodisintegration of composite material; consequently ester bonds were main units during fungal consumption. Composition of monomers in copolymers was also showing significant effect on the degradability which decreased with increasing content of ethylene in ethylene–propylene (EP) copolymers.     

Review and prospect of emerging contaminants in waste – Key issues and challenges linked to their presence in waste treatment schemes: General aspects and focus on nanoparticles

The presence in waste of emerging pollutants (EPs), whose behaviours and effects are not well understood, may present unexpected health and environmental risks and risks for the treatment processes themselves. EP may include substances that are newly detected in the environment, substances already identified as risky and whose use in items is prohibited (but which may be present in old or imported product waste) or substances already known but whose recent use in products can cause problems during their future treatment as waste. Several scientific studies have been conducted to assess the presence of EP in waste, but they are mostly dedicated to a single category of substance or one particular waste treatment. In the absence of a comprehensive review focused on the impact of the presence of EP on waste treatment schemes, the authors present a review of the key issues associated with the treatment of waste containing emerging pollutants. This review presents the typologies of emerging pollutants that are potentially present in waste along with the major challenges for each treatment scheme (recycling, composting, digestion, incineration, landfilling and wastewater treatment). All conventional treatment processes are affected by these new pollutants, and they were almost never originally designed to consider these substances. In addition to these general aspects, a comprehensive review of available data, projects and future R&D needs related to the impact of nanoparticles on waste treatment is presented as a case study.     

Recovery of yttrium from cathode ray tubes and lamps’ fluorescent powders: experimental results and economic simulation

In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides.Experimental results have shown that process conditions necessary to purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%.Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes.     

Biodiesel from lignocellulosic biomass – Prospects and challenges

Biodiesel can be a potential alternative to petroleum diesel, but its high production cost has impeded its commercialization in most parts of the world. One of the main drivers for the generation and use of biodiesel is energy security, because this fuel can be produced from locally available resources, thereby reducing the dependence on imported oil. Many countries are now trying to produce biodiesel from plant or vegetable oils. However, the consumption of large amounts of vegetable oils for biodiesel production could result in a shortage in edible oils and cause food prices to soar. Alternatively, the use of animal fat, used frying oils, and waste oils from restaurants as feedstock could be a good strategy to reduce the cost. However, these limited resources might not meet the increasing demand for clean, renewable fuels. Therefore, recent research has been focused the use of residual materials as renewable feedstock in order to lower the cost of producing biodiesel. Microbial oils or single cell oils (SCOs), produced by oleaginous microorganisms have been studied as promising alternatives to vegetable or seed oils. Various types of agro-industrial residues have been suggested as prospective nutritional sources for microbial cultures. Since the most abundant residue from agricultural crops is lignocellulosic biomass (LCB), this byproduct has been given top-priority consideration as a source of biomass for producing biodiesel. But the biological transformation of lignocellulosic materials is complicated due to their crystalline structure. So, pretreatment is required before they can be converted into fermentable sugar. This article compares and scrutinizes the extent to which various microbes can accumulate high levels of lipids as functions of the starting materials and the fermentation conditions. Also, the obstacles associated with the use of LCB are described, along with a potentially viable approach for overcoming the obstacles that currently preclude the commercial production of biodiesel from agricultural biomass.     

Sources and Mass Flows of Xenobiotics in Urban Water Cycles—an Overview on Current Knowledge and Data Gaps

In this study, several emerging compounds of concern in waste water are identified and discussed in relation to data available on their sources and mass flows in urban waters. In most western European situations, the highest contributions to the mass flow of xenobiotics to the urban water cycle stems from household and services applications (e.g. personal care compounds, pharmaceuticals, steroid hormones, flame retardants, fluorinated detergents etc.) as well as building and constructing environments (e.g. flame retardants, plasticizers, UV-blockers and biocides). The contribution from industrial point sources such as incineration industries e.g. coal, tar, steel and gas production (such as PAHs, PCBs, dioxins, etc.) and chemical industries are decreasing in relevance in terms of input and are hence currently of more local relevance only. In relation to identified compounds, this paper considers current data availability and its use in a range of management strategies for the mitigation or controlling of xenobiotics ‘at source’. However it also identifies major knowledge gaps relating to the behaviour and fate of organic pollutants in various sectors of the urban water cycle including stormwater management, bank- and soil infiltration as well as underground and soil passage of polluted waters. It is also discussing the major sources of a range of current day urban pollutants. The paper considers the sources of emerging pollutants in a qualitative way.     

Precious metals and rare earth elements in municipal solid waste – Sources and fate in a Swiss incineration plant

In Switzerland many kinds of waste, e.g. paper, metals, electrical and electronic equipment are separately collected and recycled to a large extent. The residual amount of municipal solid waste (MSW) has to be thermally treated before final disposal. Efforts to recover valuable metals from incineration residues have recently increased. However, the resource potential of critical elements in the waste input (sources) and their partitioning into recyclable fractions and residues (fate) is unknown. Therefore, a substance flow analysis (SFA) for 31 elements including precious metals (Au, Ag), platinum metal group elements (Pt, Rh) and rare earth elements (La, Ce, etc.) has been conducted in a solid waste incinerator (SWI) with a state-of-the-art bottom ash treatment according to the Thermo-Re® concept. The SFA allowed the determination of the element partitioning in the SWI, as well as the elemental composition of the MSW by indirect analysis. The results show that the waste-input contains substantial quantities of precious metals, such as 0.4 ± 0.2 mg/kg Au and 5.3 ± 0.7 mg/kg Ag. Many of the valuable substances, such as Au and Ag are enriched in specific outputs (e.g. non-ferrous metal fractions) and are therefore recoverable. As the precious metal content in MSW is expected to rise due to its increasing application in complex consumer products, the results of this study are essential for the improvement of resource recovery in the Thermo-Re® process.