Estimation of nitrogen flow change in Beijing,China, for the years 1995, 2000, and 2004

Rapid economic growth in China has led to environmental pollution. Recycling nutrients is essential for sustainable agriculture, and it is necessary to estimate the amount of available organic resources in order to achieve this. Using nitrogen as a tracer, we estimated the organic resource flows in 1995, 2000, and 2004 in Beijing. The agricultural nitrogen flow was calculated from the fertilizer, agricultural product, and byproduct flows. The livestock nitrogen flow was calculated from the feed, excretion, and stock flows. The human nitrogen flow was calculated from the food intake, excretion, and food waste flows. The amounts of recyclable organic resources were estimated from these nitrogen flows. The Daxing, Fangshan, Miyun, Shunyi, and Tongzho areas had high nitrogen loads in 2004, as did the outer suburbs, but Beijing proper had an extremely low nitrogen flow and the inner suburbs had low nitrogen flows. The estimated amount of compost that could be produced from domestic organic waste across Beijing was equivalent to 88,100 t of nitrogen. The Beijing area contains 394,100 ha of farmland, so, if the compost was applied at an equivalent of 100 kg of nitrogen per hectare, the equivalent of 48,000 t of nitrogen would be surplus.     

Preparation,sintering behavior,and expansion performance of ceramsite filter media from dewatered sewage sludge,coal fly ash,and river sediment

The main aim of this study is to assess the preparation, sintering behavior, and expansion performance of ceramsite filter media (CFM) from dewatered sewage sludge, coal fly ash, and river sediment without using any natural resources. The results showed that the investigated physical properties of lab made CFM met with the China’s industrial standard of CJ/T 299-2008 and the concentration of heavy metals in the lixivium was lower than the threshold of GB 5085.3-2007. During the sintering process, the relationships between ignition loss rate, expansion rate, and sintering temperature could be well described simultaneously by the 3-order polynomial fitting curve, with high correlation coefficient values (R ² > 0.999). The fitting curves of the ignition loss rate and expansion rate had one peak and one valley, respectively, and their cut-off point that is the sintering temperatures were the same (700 °C). The whole sintering process could be divided into two stages. The ignition loss rate was gradually increased in both the stages. At the same time, the expansion rate was decreased in the first stage and then increased in the second stage. The significance of this work is to pursue the concept of sustainable development.     

Behavior of As,Cd, Co,Cr, Cu,Pb, Ni,and Zn at the soil/plant interface around an uncontrolled landfill (Casablanca,Morocco)

The present work undertaken in the environmental context aims to study the distribution of heavy metals in plants that grow naturally around uncontrolled landfills. The study's goal was to identify plants that can be used to remediate contaminated soils. For this purpose, 14 plants species and their rhizospheric soil samples were collected and analyzed for arsenic, cadmium, cobalt, chromium, copper, lead, nickel, and zinc by inductively coupled plasma‐atomic emission spectrometry. The results showed the presence of elevated metal concentrations in soil, many exceeding the regulatory values, and that many species exhibited an ability to accumulate multiple metals in their shoots and roots without sustaining toxicity. This was confirmed by bioconcentration and translocation factors generally higher than 1.     

Thermal,Rheological, Mechanical and Morphological Behavior of High Density Polyethylene and Carboxymethyl Cellulose Blend

In this study water soluble sodium carboxymethyl cellulose (CMC) was blended with high density polyethylene (HDPE) by peroxide-initiated melt compounding technique. The compatibility of the blended polymers were carried out by silane crosslinking agent. A series of blends were prepared by varying the CMC contents up to a maximum of 50 phr. The physical properties of non-crosslinked and crosslinked blends were investigated in detail. FTIR analysis of crosslinked blend confirmed the presence of Si–O–Si and Si–O–C absorption peaks at 1050 and 1159 cm^?1. Thermal stability of crosslinked blends improved as compared to its non-crosslinked congener. Rheological study of crosslinked blends illustrated high complex viscosity and dynamic shear storage modulus. The tensile strength of virgin polyethylene was 8.1 MPa whereas the maximum tensile strength of 19.6 MPa was observed in crosslinked blend. Similarly lower deformation was observed in crosslinked blends under static load. Scanning electron microscopy of crosslinked formulations also showed strong adhesion between the polymers interface. The compatibility of HDPE and CMC is attributed to both free radical and condensation reactions.     

Clay, Phosphate Adsorption, Dispersion, and Rheology

Soluble phosphate is a common ingredient of fertilizer used in agriculture production all over the world. This chemical mixed with soil is transported into the water and marine environment via rainfall causing a range of environmental problems such as toxic algae bloom. Kaolin clay is a common material found in soil and is used as a model system to understand the effects of phosphate adsorption on the flocculation/dispersion of the clay slurries. In the topics, torrential downpours are common. The large water flow will easily disperse the unflocculated or weakly flocculated sediments over a wide area including river and marine environments. Phosphate adsorption was found to weaken the interparticle forces between clay platelets in the slurries. At high enough concentration, it will completely deflocculate the clay slurries, i.e. the net interparticle force is repulsive. A deflocculated slurry is characterised by a low viscosity and no yield stress. As a result, it is much easier to disperse this slurry over a wide area possible even in a small downpour. This study will present the flow and yield stress behaviour of kaolin clay slurries under the influence of adsorbed phosphate.     

Physical,Mechanical, and Morphological Characteristics of Extruded Starch Acetate Foams

Starch acetates with degrees of substitution (DS) of 0.57, 1.11, 1.68, and 2.23 were prepared and extruded with either water or ethanol. The microstructure, physical properties (radial expansion ratio [RER] and unit density), mechanical properties (spring index [SI] and compressibility), and crystalline structure of the foams were investigated. The functional properties were a function of DS and blowing agent type. When water was used as the blowing agent and DS increased, the foams were pale yellow, with rough and uneven surfaces. The cells were dense, with thick cell walls. Lower RER and SI, with higher DS, were associated with high unit density and compressibility. When ethanol was used as the blowing agent, contrary results were observed. The snow-white foams had smooth surfaces, uniform cells, and smooth cell walls. High RER and SI, and low unit density and compressibility were observed. The changes in SI and compressibility with RER also were examined and found to depend on the type of solvent. A crystalline pattern was observed because of the formation of well-ordered structures during extrusion.     

Behaviour of Cd,Cr, Mn,Ni, Pb,and Zn in sewage sludge incineration by fluidised bed furnace

Cd, Cr, Mn, Ni, Pb, and Zn behaviour during sewage sludge incineration was investigated in seven pilot tests using a circulating fluidised bed furnace. Dewatered sludge at a solids concentration of 15-18% was fed to the furnace either alone (two tests) or spiked with chlorinated organic compounds (five tests). The behaviour of metals in the fluidised bed furnace was studied by comparing metal concentrations in the two main ash streams: ash separated from the cyclone immediately following the fluidised bed furnace, and fly ash recovered in the final bag filter. A metal enrichment factor was defined as the ratio of metal concentration between filter ash and cyclone ash. Only Cd and Pb showed any significant enrichment. Their enrichment factors were mainly affected by chlorine concentration in the feed sludge. To check whether simple equilibrium models may explain and predict metal behaviour, experimental data were compared with percentage of the metal vaporisation in the combustion chamber predicted using a thermodynamic model. Discrepancies between model predictions and experimental results are accounted for by considering that kinetics may be a limiting factor in the formation of metal chloride gaseous species. Due to the very short sludge residence time in the fluidised bed furnace, the gaseous compounds have little chance to evolve completely.     

Novel Biodegradable Cast Film from Cherry Tree Gum,Development, Modification and Characterization

The feasibility of sweet cherry gum as a bio-based film-forming material and effect of hydrogen peroxide as a chemical modifier investigated. The influence of film compositions (gum, glycerol) and hydrogen peroxide on the physical properties of films, including solubility in water, permeability to water vapor (WVP), mechanical properties, and transparency, thermal and microstructural properties evaluated. The results showed that WVP and thickness increased by gum and glycerol concentration, but significantly decreased by hydrogen peroxide. As expected, elongation-at-break and solubility, increased at higher concentration of glycerol but the tensile strength decreased at the same condition. The film transparency was influenced by the dry weight content and was improved by higher concentrations of hydrogen peroxide. The partial degradation of polymer chain by hydrogen peroxide was observed by FTIR analysis.     

Tensile Strength, Elongation, Hardness, and Tensile and Flexural Moduli of PLA Filled with Glycerol-Plasticized DDGS

Rapid growth of the biofuel industry is generating large amounts of coproducts such as distillers dried grains with solubles (DDGS) from ethanol production and glycerol from biodiesel. Currently these coproducts are undervalued, but they have application in the plastics industry as property modifiers. The objective of this research effort is to quantify the effects on mechanical properties of adding DDGS and glycerol to polylactic acid (PLA). The methodology was to physically mix DDGS, as filler, with PLA pellets and injection mold the blends into test bars using glycerol as a plasticizer. The bars were subject to mechanical testing procedures to obtain tensile strength, tensile and flexural moduli, elongation to break, and surface hardness of blends from 0 to 90?%, by weight, of plasticized filler. Blends were typically relatively brittle with little or no yielding prior to fracture, and the addition of glycerol enabled molding of blends with high levels of DDGS but did not increase strength. Any presence of filler decreased the tensile strength of the PLA, and 20?C30?% filler reduced strength by 60?%. The 35?C50?% filled PLA had about one-fifth the value for pure PLA; at 60?C65?% filler level, about 10?% tensile strength remained; and over 80?% filler, 95?% of the strength was lost. Over 20?% filler, the tensile modulus decreased. The 35?% plasticized, filled blend yielded about one-half the stiffness as the pure PLA case; flexural modulus trended in the same manner but demonstrated a greater loss of stiffness. Most blends had less than 3?% elongation to break while surface hardness measurements indicated that up to 60?% filler reduced Shore D hardness by less than 20?%. The tensile strength and modulus data are consistent with the findings of other researchers and indicate that the type of filler and amount and sequence of plasticization are secondary effects, and the total PLA displaced is the dominant factor in determining the mechanical strength of the PLA and DDGS blends. Up to 65?% plasticized DDGS filler can be injection molded, and sufficient mechanical strength exists to create a variety of products. Such a novel material provides higher-value utilization of the biofuel coproducts of glycerol and DDGS and maintains the biodegradable and biocompatible nature of PLA.     

Applied geologic,microbiological, and engineering constraints of in-situ BTEX bioremediation

An in-situ bioremediation project has been designed and constructed for a site in south-central Kansas just north of Wichita. A pipeline leaked an unknown quantity of refinedfuels in the 1970s. The spill was undetected until hydrocarbons were found in a nearby municipal water supply well. Of concern, from a regulatory perspective, are the alkylbenzene components found in the groundwater, including benzene, toluene, ethylbenzene, and xylene (BTEX). Initial abatement procedures, including free product removal and pumping, had become ineffective. In-situ bioremediation was selected to complete the restoration process. The project emphasizes the need for a strong understanding of the geologic and hydrogeologic conditions prevalent under the site. Site studies were conducted to determine the distribution and mass of the contaminant and the hydraulic regime. Laboratory microbial studies were used to determine the efficacy of nitrate as a primary electron acceptor. Information from site studies was used to design a treatment system tailored to the requirements of the site. The treatment system is designed to deliver the maximum amount of nutrient-enriched water to the contaminated zone while maintaining hydraulic control of the site.     

Liquid balance monitoring inside conventional,Retrofit, and bio-reactor landfill cells

The Outer Loop landfill bioreactor (OLLB) in Louisville, KY, USA has been the site of a study to evaluate long-term bioreactor performance at a full-scale operational landfill. Three types of landfill units were studied including a conventional landfill (Control cell), a new landfill area that had an air addition and recirculation piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for liquids recirculation (Retrofit cell). During the monitoring period, the Retrofit, Control, and As-Built cells received 48, 14, and 213 L Mg^?1 (liters of liquids per metric ton of waste), respectively. The leachate collection system yielded 60, 57 and 198 L Mg^?1 from the Retrofit, Control, and As-Built cells, respectively. The head on liner in all cells was below regulatory limits. In the Control and As-Built cells, leachate head on liner decreased once waste placement stopped. The measured moisture content of the waste samples was consistent with that calculated from the estimate of accumulated liquid by the liquid balance. Additionally, measurements on excavated solid waste samples revealed large spatial variability in waste moisture content. The degree of saturation in the Control cells decreased from 85% to 75%. The degree of saturation increased from 82% to 83% due to liquids addition in the Retrofit cells and decreased back to 80% once liquid addition stopped. In the As-Built cells, the degree of saturation increased from 87% to 97% during filling activities and then started to decrease soon after filling activities stopped to reach 92% at the end of the monitoring period. The measured leachate generation rates were used to estimate an in-place saturated hydraulic conductivity of the MSW in the range of 10^?8 to 10^?7 m s^?1 which is lower than previous reports. In the Control and Retrofit cells, the net loss in liquids, 43 and 12 L Mg^?1, respectively, was similar to the measured settlement of 15% and 5–8% strain, respectively (Abichou et al., 2013). The increase in net liquid volume in the As-Built cells indicates that the 37% (average) measured settlement strain in these cells cannot be due to consolidation as the waste mass did not lose any moisture but rather suggests that settlement was attributable to lubrication of waste particle contacts, softening of flexible porous materials, and additional biological degradation.     

Health risk assessment of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in circumjacent soil of a factory for recycling waste electrical and electronic equipment

The aim of the study was to determine the potential environmental contamination in a typical factory for recycling waste electrical and electronic equipment in Shanghai. Heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in the soil around the factory have been evaluated in this paper. Compared with the background value, the concentrations of six metals detected in all the samples were higher, which showed that toxic metals were released into soil around the factory. Compared with the Environmental Quality Standards for Soils, China grade III, all the six metals are under soil guidelines. The non-cancer risk in different directions from the factory was in the order of: the north > the west > the south > the east. For inhalation and ingestion, the non-cancer risk in the soil west of the factory was biggest. Nevertheless, the non-cancer risk in the soil north of the factory was the biggest for dermal contact. The trend of cancer risk was the west > the south > the north > the east. The non-cancer risk and the carcinogenic risk for Cr, Ni, and Cd were all below the limiting value. This study might provide a reference for the risk assessment involved in electronic waste management and recycling activities.     

Tree establishment and growth at Pitsea landfill site,Essex, U.K.

Investigations at an 11-year-old landfill site have shown that soil moisture was positively, and soil oxygen was negatively correlated with temperature and concentration of soil methane generated by decomposition of the underlying landfill materials. A thin (0.2 m) cover of soil-forming material over the landfill showed acute oxygen deficiency and high temperatures. The high moisture content of this cover was probably caused by upward movement of water from within the landfill across a temperature gradient. Nearly all the trees of five species on the thinnest (0.2 m) cover died, but survival and growth was markedly improved on 1.5 m additional clay cover over the landfill. This material prevented landfill gas contamination, and also contained sufficient plant-available soil moisture to negate the large soil moisture deficits the area experiences in most summers. The evidence presented shows that landfill sites are dynamic in the distribution of landfill temperature and gas emissions and the planning of tree planting schemes should take this into account.     

Tensile Strength, Elongation, Hardness, and Tensile and Flexural Moduli of Injection-Molded TPS Filled with Glycerol-Plasticized DDGS

Continuing growth of biofuel industries is generating large amounts of coproducts such as distillers dried grains with solubles (DDGS) from ethanol production and glycerol from biodiesel. Currently these coproducts are undervalued, but they have application in the plastics industry as property modifiers. This research effort has quantified the effects on mechanical properties of adding DDGS and glycerol to a commercial thermoplastic starch (TPS). The methodology was to physically mix DDGS, as filler, with the TPS pellets and injection mold the blends into test bars using glycerol as a processing aid. The bars were then mechanically tested with blends from 0 to 65 %, by weight, of plasticized filler. The test bars were typically relatively brittle with little yielding prior to fracture with elongation between 1 and 3 %. The addition of glycerol enabled molding of blends with high levels of DDGS but did not increase strength. Any presence of filler decreased the tensile strength of the starch, and up to 30 % filler, the tensile strength drops about 15 %. The 20 and 50 % blends (without glycerol) have slightly greater stiffness than pure starch. With some other blends, the presence of plasticized filler degrades the tensile modulus with 35 % filler yielding about 1/3 the stiffness. Changes in the flexural modulus are much more pronounced as 20–25 % filled TPS has a 30 % increase in flexural stiffness. In terms of surface hardness, blends up to 60 % filler are within 20 % of the TPS baseline.     

Trends in Fish Community Structure,Biomass, and Production in Three Algoma,Ontario, Lakes

Long-term (i.e. >10 years) whole community fish dataincluding catch-per-unit-effort, abundance, biomass, andproduction from three lakes were used: 1) to examine variabilityin fish population and community measures among years using wholelake assessments of fish populations derived from mark recaptureexperiments, 2) to assess implications arising from monitoringindividual species vs. the whole fish community, and 3) toascertain whether, in fisheries assessments (science) a commonlyused surrogate measure, [catch-per-unit-effort (CPUE)] reflectedannual changes in the fish assemblage, and thus may be a goodestimator of abundance. High, long-term variability was evident in the abundance andbiomass of a fish species in our lakes, yet the communityremained relatively stable in terms of its biomass andproduction. Changes in total fish community biomass appear drivenby large species, which, relative to small fish species, remainstable among years. Among years, species richness remainedstable; however, fish species changed in the community. AnnualCPUE was found to be a suitable surrogate for abundance (N) ofsmall fishes; CPUE x mean weight of the catch (bCPUE) was asuitable surrogate for biomass (B) of large fishes. Prior toconcluding that a change in a fish population has occurred as aresult of a stressor, care must be taken to critically examinethe level of population assessment in order to avoid acceptingpotentially invalid conclusions.     

Modeling hydrology and reactive transport in roads: the effect of cracks, the edge, and contaminant properties

The goal of this research was to provide a tool for regulators to evaluate the groundwater contamination from the use of virgin and secondary materials in road construction. A finite element model, HYDRUS2D, was used to evaluate generic scenarios for secondary material use in base layers. Use of generic model results for particular applications was demonstrated through a steel slag example. The hydrology and reactive transport of contaminants were modeled in a two-dimensional cross section of a road. Model simulations showed that in an intact pavement, lateral velocities from the edge towards the centerline may transport contaminants in the base layer. The dominant transport mechanisms are advection closer to the edge and diffusion closer to the centerline. A shoulder joint in the pavement allows 0.03 to 0.45 m(3)/day of infiltration per meter of joint length as a function of the base and subgrade hydrology and the rain intensity. Scenario simulations showed that salts in the base layer of pavements are depleted by 99% in the first 20 years, whereas the metals may not reach the groundwater in 20 years at any significant concentrations if the pavement is built on adsorbing soils.     

Residential Flood Damage After Hurricane Floyd,Mold, Household Remediation,and Respiratory Health

We conducted a retrospective, cross‐sectional study of flooding, mold exposure, remediation, and respiratory symptom prevalence on a random sample of respondents from Bound Brook, New Jersey, a community that received extensive flood damage from Hurricane Floyd in September 1999. Over 3,000 homes were impacted, some with water damage to the second floor. Many required condemnation. In 2001 to 2002 we conducted a randomized telephone survey of 29 families still living in flood‐damaged and repaired homes and 18 families who had not experienced flood damage from Floyd. Flood status was the last question on the interview, leaving the interviewer effectively blinded as to status. Flood damage was a strong predictor of mold growth (p < 0.001), and there was a strong association between flooding and physician‐confirmed respiratory symptoms in the aftermath of the flood (28 of 29 cases vs. 10 of 18 referents; p < 0.001). There was also an association between flood status and continued symptom prevalence in the month prior to the interviews (22 of 29 cases vs. 6 of 18 referents; p < 0.01). Most flooded homes required removal and replacement of various building materials, which was usually delayed for days or weeks pending re‐occupancy. Many occupants participated in the renovation without adequate personal protection. Persons assisting with cleanup work were more likely to report five or more symptoms (p < 0.002). Smokers with mold damage reported five or more symptoms in the 30 days before the interviews, more frequently than nonsmokers with mold damage. These results are consistent with previous reports of flooding, mold, and illness, but demonstrate that self‐remediation of mold (particularly with lack of training and personal protective equipment) and smoking are significant risk factors for mold‐related symptoms. Exposure during cleanup of moldy materials was a significant contributor to symptoms, and recommendations should include more reliance on professionals and enhanced personal protective equipment. © 2013 Wiley Periodicals, Inc.     

In-Situ Fenton-Like Oxidation of Volatile Organics: Laboratory,Pilot, and Full-Scale Demonstrations

Laboratory, pilot, and full-scale experiments were used to evaluate and optimize the ISOTEC^SM remedial process at a warehousing facility in Union, New Jersey. Based on modified Fenton's oxidative chemistry, the ISOTEC^SM process uses a proprietary catalytic agent that delays formation of reactive hydroxyl radicals. This allows adequate dispersion of the hydroxyl radicals, which is an oxidizing agent, throughout a contaminant plume. Ground-water at the site was contaminated with high levels of gasoline and waste oil constituents, principally BTEX and MTBE. Bench scale microcosm studies were used to evaluate the appropriate site-specific stoichiometric relationships between catalyst, stabilizers, and oxidizers; the effect of contaminant type and concentration; and the pH optima. Based on results of the laboratory studies, a pilot-scale study was performed at the site. One injection point for catalyst, stabilizers, and oxidant was installed in the contaminated zone at the site, with one hydraulically connected downgradient well used for monitoring. A single treatment of the reagents in the optimal stoichiometry determined from the laboratory study was injected in-situ over a period of three days. A 98.5 percent reduction in volatile organics was observed in the area treated, with the radial extent of treatment estimated to be approximately 20 feet, based on the presence of hydroxyl radicals detected in hydraulically connected areas and at the surface. The full-scale process employed six injection points and three treatment cycles over a three-month period. Subsequent to treatment, contaminant levels were either nondetectable or were reduced to below applicable New Jersey groundwater standards, with regulatory closure on the site achieved in less than one year.     

Organometals of tin, lead and mercury compounds in landfill gases and leachates from Bavaria, Germany

Organo-Sn, -Pb and -Hg compounds were monitored in gases and leachates of 11 municipal waste landfills and one hazardous waste landfill from Bavaria, Germany, with the objectives to estimate the methylation of Sn, Pb and Hg and to assess the risk of their release into the adjacent environment. In the gases, tetramethyl Sn predominated (>80% of total gaseous Sn) with concentrations up to 160mug Sn m(-3). Dimethyl-Hg and tetramethyl-Pb were only occasionally detected with concentrations up to 2.9 and 2.1mugm(-3) as Hg or Pb, respectively. In all leachates, trimethyl-Sn dominated with a maximum concentration of 2100ng Sn L(-1). No organo-Pb compounds were found, and monomethyl-Hg was detected in only one leachate. The concentrations of trimethyl-Sn were up to 100-fold higher in the condensate water than in leachates, and the concentrations of organo-Sn compounds were lower in the adjacent groundwater than in the corresponding leachates. The high abundance of methylated Sn species in the gases and leachates indicates Sn methylation, suggesting the landfill as a source for organo-Sn compounds. In comparison, methylation of Hg and Pb was of little importance, probably due to low Hg concentrations and low rates of Pb methylation in the landfill. The risks of organo-Sn compounds release to the adjacent air is low due to flaring of landfill gases. However, there is probable release of organo-Sn compounds, especially trimethyl-Sn, to the adjacent groundwater.     

Arsenic,cadmium, lead and thallium in coal ash from individual household furnaces

52 coal ash samples from individual households were analyzed to determine the pH and the concentrations of four toxic elements: arsenic, cadmium, lead and thallium. The method used was atomic absorption spectrometry with graphite-furnace atomization. The ash samples originated from various coal grades and statistical analysis showed existing correlations between the concentrations of studied elements, pH and the coal grades. The maximum concentrations of arsenic, cadmium, lead and thallium were 50,900, 43,500, 128,900, and 6660 µg/kg, respectively. The results were compared with the published data for the ash of industrial origin.