Comparative Thermodynamic Study on the Contribution of the Autocondensation and Copolymerization Reactions for the Tannins of the Subspecies of Acacia nilotica

Autocondensation and copolymerization reactions of the Acacia nilotica subspecies tomentosa (Ant) and the subspecies adansonii (Ana) tannins extracts solutions have been studied at several pH values by thermomechanical analyzer. Results of chemical analysis of these tannins revealed that the studied tannins, Ant and Ana contained high percentages of extractable tannins (54 and 57 %) for and polyphenolic materials (78 and 80 %) respectively. Different hardeners such as paraformaldehyde, Urea and pMDI were added at different ratios and their polycondensation reactions was studied and compared with their autocondensation ones. The aim was to evaluate the tannins suitability for the production of commercially and technically viable tannin adhesives with reduced Formaldehyde emission for wood products and to study the interference between the autocondensation and the copolymerization reaction. The obtained results of autocondensation reaction for both of the tannins studied showed that the best Young’s modulus values for Ant (3,500 and 2,750 MPa) and Ana (2,650 and 2,620 MPa) were obtained at pH 5 and 7. The Young’s modulus values obtained by the tannins Ant were higher than those achieved by Ana. This indicates that the Ant is more reactive than Ana. These results were also in line with results achieved by the gel time for both of the tannins. Gel time results indicate that the reactivity of both tannins increased towards alkalinity with Ana being more reactive at alkaline pH. Addition of 8 % of paraformaldehyde was adversely affecting the autocondensation reactions, as the best Young’s modulus values were achieved at pH 4 for Ant tannins. As for Ana the higher Young’s modulus values (2,000 and 2,310 MPa) were achieved at pH 5 and 7. This indicates that autocondensation reaction was contributed to the final network of the copolymerization reaction. When smaller ratio of paraformaldehyde and Urea (5 %) was added to Ant tannins it favors the autocondensation reaction and the best Young’s modulus values were obtained at pH 5 and 7. Addition of pMDI (10–30 %) was found to decrease the temperature of copolymerization and the obtained Young’s modulus values by Ant were lower than those obtained by autocodensation reaction. Best Young’ modulus values were obtained by Ant at pH 5 and 7. Ana gave the best Young’s modulus values at pH 4 and 5 indicating that the autocondensation appears to depress the copolymerization reactions. The obtained results by both reactions were very important from technical and economical point of view as they concluded that it is very possible to produce adhesives system with zero emission depending on the tannins autocondensation reaction and pH values. Reduction of formaldehyde emission was also possible upon addition of smaller amount of paraformaldehyde and Urea.     

The Toxicity of Laboratory Burned Oil to the Amphipod Allorchestes compressa and the Snail Polinices conicus

Acute 96 h LC50 values of the burned-oil–water-accommodated-fraction (BWAF) and burned-oil-residue-mixture (BRM) were determined in semi-static bioassays with seawater, using the amphipod Allorchestes compressa (Dana). Sublethal bioassays (suppression of burying behaviour over 30 min and 24 h exposure) were also conducted for these toxicants, using the marine sand snail Polinices conicus (Lamarck) as the test organism.The mean (n=4) 96 h LC50 (S.E.) value for BWAF was 80 (4.1)% and for BRM was greater than 100%. No-observed-effect-concentration (NOEC) and lowest-observed-effect-concentration (LOEC) for the both toxicants were 40% and 60% respectively. The burying behaviour of the snails after 30 min exposure to both toxicants was not affected with NOEC values greater than 100%. The 24 h EC50 (S.E.) value for BWAF was 60 (2.7)% with 10% NOEC and 20% LOEC values. The respective 24 h EC50 value for BRM was greater than 100% with 40% NOEC and 60% LOEC values.     

Local Circulation with Aeolian Dust on the Slopes and Foot Areas of the Tianshan and Kunlun Mountains around the Taklimakan Desert, China

Four automatic weather stations (AWS) were installed on the slopes and foot areas of the Tianshan and Kunlun Mountains along a longitude of 80 degrees east: (1) Taglak 2400 m a.s.l., (2) Aksu 1000 m, (3) Kartash 2800 m, and (4) Qira 1700 m. These two slopes face the Taklimakan Desert. Tagliak lies on the southern slope of Tianshan, and Kartash on the northern slope of Kunlun. The meteorological characteristics of the mountainous regions were investigated using surface data obtained during an intensive observation period (IOP) in spring 2002. It was found that visibility on the slopes decreases in the daytime, and there is no relationship between visibility and wind speed in the mountainous areas. Two snow layers containing dust particles were observed in the snow cover in Taglak during the IOP in spring 2003. These results suggest that a warm air parcel containing aeolian dust climbs over the slopes of the mountainous areas, and dust particles in the mountainous areas are transported from the foot areas.     

Monitoring of the Degradation Activities and the Diversity of the Microbial Community Degrading Refinery Waste Sludge

The biodegradation of n-alkanes and branched alkanes from waste sludge were observed in landfarming soils of Motor Oil Hellas (a petroleum refinery) and changes in the bacterial communities in the soils were monitored during the remediation. Bacterial 16S rRNA gene (rDNA)-based community fingerprint patterns were obtained from soil samples by terminal restriction fragment length polymorphism (T-RFLP) analysis. Changes in T-RFLP fingerprints, as well as in the petroleum contaminant composition of the polluted soil, correlated with degradation activities in field tests.     

Guidelines for the evaluation and assessment of the sustainable use of resources and of wastes management at healthcare facilities.

This paper presents guidelines that can be used by managers of healthcare facilities to evaluate and assess the quality of resources and waste management at their facilities and enabling the principles of sustainable development to be addressed. The guidelines include the following key aspects which need to be considered when completing an assessment. They are: (a) general management; (b) social issues; (c) health and safety; (d) energy and water use; (e) purchasing and supply; (f) waste management (responsibility, segregation, storage and packaging); (g) waste transport; (h) recycling and re-use; (i) waste treatment; and (j) final disposal. They identify actions required to achieve a higher level of performance which can readily be applied to any healthcare facility, irrespective of the local level of social, economic and environmental development. The guidelines are presented, and the characteristics of facilities associated with sustainable (level 4) and unsustainable (level 0) healthcare resource and wastes management are outlined. They have been used to assess a major London hospital, and this highlighted a number of deficiencies in current practice, including a lack of control over purchasing and supply, and very low rates of segregation of municipal solid waste from hazardous healthcare waste.     

Critical evaluation of the use of the hydroxyapatite as a stabilizing agent to reduce the mobility of Zn and Ni in sewage sludge amended soils

The leachability of zinc (Zn) and nickel (Ni) was investigated in various soil types amended with sewage sludge and sewage sludge treated with hydroxyapatite. Sandy, clay and peat soils were investigated. For leachability tests, plastic columns (diameter 9 cm, height 50 cm) were filled with moist samples up to a height of 25 cm. Sewage sludge (1 kg) was mixed with 4.6 kg of clay and sandy soils and with 6.7 kg of peat soil. For sewage sludge mixtures treated with hydroxyapatite, 0.5 kg of the hydroxyapatite was added to 1 kg of the sewage sludge. Neutral (pH 7) and acid precipitation (pH 3.5) were applied. Acid precipitation was prepared from concentrated HNO(3), H(2)SO(4) and fresh doubly distilled water. The amount of precipitation corresponded to the average annual precipitation for the city of Ljubljana, Slovenia. It was divided into eight equal portions and applied sequentially on the top of the columns. The results indicated that the leachabilities of Zn in sewage sludge amended peat and clay soils were low (below 0.3% of total Zn content) and of Ni in sewage sludge amended sandy, clay and peat soil below 1.9% of total Ni content. In sewage sludge amended sandy soil, the leachability of Zn was higher (11% of Zn content). The pH of precipitation had no influence on the leachability of either metal. Treatment of sewage sludge with hydroxyapatite efficiently reduced the leachability of Zn in sewage sludge amended sandy soil (from 11% to 0.2% of total Zn content). In clay and peat sewage sludge amended soils, soil characteristics rather than hydroxyapatite treatment dominate Zn mobility.     

An investigation on the potential of metal recovery from the municipal waste incinerator in Taiwan

This study aimed to identify distribution of metals and to estimate the amount of these metals that can be potentially recovered from incineration residues. First, the partitioning behavior of Cr, Cu, Fe, Cd, Al, Zn, and Pb in bottom ash and fly ash was investigated in one large municipal waste incinerator in Taiwan. In addition, the material flow analysis (MFA) method was used to estimate the material flux of metals within incinerator plant, and to calculate the amount of metal recovery. According to the findings of this study, six metals (Fe, Al, Cu, Zn, Cr, and Pb) concentrated in bottom ash mostly, while Cd existed primarily in fly ash. The weight percentages of Fe (4.49%), Al (5.24%), Cu (1.29%), Zn (2.21%), and Pb (0.58%) in incinerator ash are high, and even higher than the compositions of natural minerals. Finally, the amount of Cr, Cu, Fe, Cd, Al, Zn and Pb that can be potentially recovered from incineration residues will reach 2.69 x 10(2), 1.46 x 10(4), 4.91 x 10(4), 6.92 x 10(1), 5.10 x 10(4), 1.85 x 10(4) and 4.66 x 10(3) ton/yr, respectively.     

Influence of the composition of the initial mixtures on the chemical composition,physicochemical properties and humic-like substances content of composts

The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1–6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters.The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts.On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids.     

Toxicity of the weathered crude oil used at the Newfoundland offshore burn experiment (NOBE) and the resultant burn residue

The toxicity of the weathered crude oil Alberta sweet mixed blend (ASMB) used at the Newfoundland offshore burn experiment (NOBE) and the resultant burn residue, was investigated using the Environment Canada water-accommodated fraction (WAF) preparation method and exposure protocol. Rainbow trout (Oncorhynchus mykiss) were exposed to freshwater WAF prepared from weathered ASMB. Three-spine stickleback (Gasterosteus aculeatus), and the gametes of the white sea urchin (Lytechinus pictus) were exposed to saltwater WAF prepared from both weathered ASMB and burn residue. The fish tests were of 96 h duration, and the end-point was lethality. The urchin test was of 20 min duration, and the end-point was inhibition of fertilization. GC/MS headspace analysis of 28 analytes showed low levels of volatile hydrocarbons. The maximum measured concentration was 1.1 μg ml⁻¹ in 104 samples from all WAF concentrations in both seawater and freshwater at all exposure times (0, 24 and 72 h). All samples were found not to be toxic to all species tested.     

Influence of flue gas cleaning system on the energetic efficiency and on the economic performance of a WTE plant

Gas cleaning systems of MSW (Municipal Solid Waste) incinerators are characterised by the process employed to remove acid gases. The commonly used technologies for acid gas removal are: (1) dry treatment with Ca(OH)₂ or (2) with NaHCO₃, (3) semi-dry process with Ca(OH)₂ and (4) wet scrubbing. In some recent plants beside a wet cleaning system, a dry neutralization with Ca(OH)₂ is used. The goal is to reduce the amount of acid to be removed in the wet treatment and the liquid effluents produced. The influence of these different technologies on the electrical efficiency was investigated by a detailed simulation of a WTE (Waste To Energy) plant with a capacity of about 100,000 t/y of MSW. The effects of the different gas cleaning systems on electrical efficiency were significant. The difference of efficiency between the most advantageous technology, which is dry treatment with NaHCO₃, and the least advantageous technology which is semi-dry treatment, is about 0.8%. A simple economic analysis showed that the few advantages of dry technologies can often be lost if the costs of chemicals and the disposal of products are considered.     

Effects of the type of sintering atmosphere on the chromium leachability of thermal-treated municipal solid waste incinerator fly ash

The sintering process offers an opportunity to combine detoxification and resource recovery for the treatment of municipal solid waste (MSW) incinerator fly ash. However, the chromium (Cr) in the sintered fly ash becomes more readily leachable with increasing sintering time and temperature, thus posing severe threats to the environment and human health when the sintered ash is recycled or reused. This study investigated the enhanced leachability of fly ash containing Cr, by heating the chromium (III) oxide (Cr2O3)-spiked fly ash to 800 degrees C in atmospheres containing air, nitrogen gas (N2), and 5% H2 + 95% N2, respectively. The results indicated that trivalent chromium was converted to its soluble hexavalent form during sintering in the air atmosphere; whereas sintering in a nitrogen atmosphere significantly reduced the leachability of Cr due to lack of oxygen (O2) to oxidize. The effects of the sintering temperature on the total chromium content and the leaching concentration in the toxicity characteristic leaching procedure (TCLP) extract are also discussed.     

Investigating the Uncertainties in the Simple Mass Balance Equation for Acidity Critical Loads for Terrestrial Ecosystems in the United Kingdom

The Simple Mass Balance (SMB)equation has been developed and used as one ofthe principal methods for calculating criticalloads of acidity for forest ecosystems. Criticalloads have formed the basis for informing policyrelated to the control and abatement of emissionsof acidifying pollutants. The SMB equationrelies on a variety of assumptions and dataderived from a variety of sources. Each of thesecomponent constituents has a potential source oferror depending on the method(s) used for theirderivation and the value(s) assigned. The resultis the possibility of generating a range ofcritical load values for a single ecosystem. This paper summarises the SMB equation, examinesthe uncertainties in deriving input values andreviews other works on the key assumptions.     

Integrated waste management--looking beyond the solid waste horizon

Waste as a management issue has been evident for over four millennia. Disposal of waste to the biosphere has given way to thinking about, and trying to implement, an integrated waste management approach. In 1996 the United Nations Environmental Programme (UNEP) defined 'integrated waste management' as 'a framework of reference for designing and implementing new waste management systems and for analysing and optimising existing systems'. In this paper the concept of integrated waste management as defined by UNEP is considered, along with the parameters that constitute integrated waste management. The examples used are put into four categories: (1) integration within a single medium (solid, aqueous or atmospheric wastes) by considering alternative waste management options, (2) multi-media integration (solid, aqueous, atmospheric and energy wastes) by considering waste management options that can be applied to more than one medium, (3) tools (regulatory, economic, voluntary and informational) and (4) agents (governmental bodies (local and national), businesses and the community). This evaluation allows guidelines for enhancing success: (1) as experience increases, it is possible to deal with a greater complexity; and (2) integrated waste management requires a holistic approach, which encompasses a life cycle understanding of products and services. This in turn requires different specialisms to be involved in the instigation and analysis of an integrated waste management system. Taken together these advance the path to sustainability.     

Understanding the chemical and mineralogical properties of the inorganic portion of MSWI bottom ash

This paper investigates the changes of mineralogical composition of bottom ash in the environment. The chemical and mineralogical bulk composition was determined by X-ray fluorescence (XRF) and X-ray powder diffraction (XRPD) Rietveld method. Single bottom ash particles were investigated by optical microscopy, scanning electron microscopy with quantitative energy-dispersive X-ray microanalysis (SEM/EDX) and electron probe micro analysis (EPMA). SEM/EDX and EPMA are valuable complement to bulk analysis and provide means for rapid and sensitive multi-elemental analysis of ash particles. The fresh bottom ash consists of amorphous (>30 wt.%) and major crystalline phases (>1 wt.%) such as silicates, oxides and carbonates. The mineral assemblage of the fresh bottom ash is clearly unstable and an aging process occurs by reaction towards an equilibrium mineral phase composition in the environmental conditions. The significant decrease of anhydrite and amorphous contents was observed in the aged bottom ash, leading to the formation of ettringite, hydrocalumite and rosenhahnite under atmospheric conditions. In the water-treated sample, the calcite contents increased significantly, but ettringite was altered by the dissolution and precipitation processes in part, to produce gypsum, while the remaining part reacted with chloride to form hydrocalumite. Gypsum and other Ca based minerals may take up substantial amounts of heavy metals and subsequently control leaching behaviour of bottom ash.     

Lead Speciation in the Sediments of the Heavily Polluted Western Harbor of Alexandria

The Western Harbor (WH) became under stress in the past decades, following successive increase in population. This study deals with local distribution of total lead and its species in the WH sediments. The lead content was high and there was a relationship between its enrichment and oil dispersed from ships. The lowest total lead value was found in the harbor middle far from direct effects of pollution. A five-step sequential extraction scheme was applied to illustrate the contribution shared by each individual fraction in the total lead concentration in the WH sediments. The exchangeable fraction (F1) was very low. The bound to carbonate fraction (F2), the bound to iron-manganese oxide fraction (F3) and the bound to organic matter—sulfide fraction (F4) ranked fourth, second and third in abundance. Oxygen was the main factor controlling the value of F2. F3 gave a direct relationship with total lead. The high levels of F4 occurred at locations of low salinity and enriched with organic matter. The residual fraction (F5) dominated other lead species, reflecting the sediment composition and the amounts of discharged pollutants.     

Understanding the Causes of Spills From the Supply and Handling of Chemicals at Resource Construction Sites: A Case Study

An intermediate bulk container (IBC) was punctured during its handling, releasing a refined oil product onto land at a large construction site in an environmentally sensitive region of Australia. Understanding and controlling the risks from fuel, oil, and chemical spills on the current project was of critical importance as part of the project's overall approval, and ongoing compliance depended on the project committing to minimizing all chemical and petroleum hydrocarbon spills on the site. The telehandler (forklift) did not pierce the plastic of the IBC directly (as was expected to be the case) but rather one of the tynes caught on the underside of the metal base plate (pallet belly plate), despite numerous controls being in place at the time of spill (to limit the risks of damaging the IBC), revealing a previously unreported mechanism for a fluid spill from handling of petroleum hydrocarbons and related chemicals. The investigation team used a root cause analysis (RCA) technique, based on the fishbone (Ishikawa) diagram, which was undertaken with 12 expert contributors (from the project) to identify the underlying cause: The inspection process was inadequate. This study is a companion to the article published in Winter 2014 in Remediation (Guerin, 2014) covering multiple causes of spills from plant and equipment commonly used on construction and remediation projects. ©2015 Wiley Periodicals, Inc.     

Effect of the mixing ratio on the composting of OFMSW digestate: assessment of compost quality

This study presents the results obtained in compostability tests of organic fraction of municipal solid waste (OFMSW) digestate. The final aim was to obtain mature compost without phytotoxic effects. For the evaluation of the composting process, a novel parameter describing the performance of the composting process, the relative heat generation standardized with the initial volatile solid content (RHGVS₀), was defined and evaluated at laboratory-scale. From these laboratory-scale test, the optimum operational conditions were obtained, a mixing ratio (v/v) of 1:1:0 (bulking agent:digestate:co-substrate) and with 15% of mature compost as inoculum. Subsequently, these optimum operational conditions were applied in the active phase of the composting pilot-scale reactor. The active composting stage took 7 days, subsequently a curing phase of 60 days was carried out at ambient conditions. After 30 days of curing, the mature compost showed a specific oxygen uptake rate (SOUR) of 0.14 mg O₂/g VS·h, a germination index (GI) of 99.63% and a low volatile fatty acids (VFA) concentration (41.3 AcH mg/kg_dm), being indicative of the good compost stability and maturity of the compost. The very good quality of the final compost obtained indicated that the RHGVS₀ accurately describes the performance of the composting process.

     

Study of the presence of fluorine in the recycled fractions during carbothermal treatment of EAF dust

Carbothermal treatment tests of electric arc furnace dusts (EAFD) using the Waelz kiln process were carried out in pilot-scale for the production of zinc oxide. The association of halides in the EAFD, and the recycled products, such as zinc oxide fumes and high-grade iron contents fractions were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. XRD reveals the presence of chlorine and fluorine in the dusts in the form of KCl, NaCl and CaF2. An ultra-pure fraction of zinc was obtained after the Double Leaching Waelz Oxide (DLWO) process was performed on the zinc oxide fumes. The halide contents were reduced to approximately 100 ppm Cl and 700 ppm F. The rest of these elements are in the form of CaF2. About 65% F is volatilised as lead and zinc fluorides, 15% is expected in the magnetic fractions and 20% in non-magnetic fractions as CaF2 and MnF2, respectively.     

Effect of the Recycling and Annealing on the Mechanical and Fracture Properties of Poly(Lactic Acid)

The aim of this work is to evaluate the use of Poly(lactic acid) (PLA) industrial waste as a source of raw material for certain applications, as well as to understand the effects of the annealing on the fracture behavior of PLA. PLA waste has been simulated by an initial step of extrusion in a single screw extruder and pelletizing. Specimens of virgin and reprocessed PLA were obtained by injection molding. An annealing treatment capable of increasing the percentage of crystallinity (determined by differential scanning calorimetry) was also analyzed in reprocessed and non reprocessed specimens. The fracture behavior was studied at slow and high testing speed, applying the linear elastic fracture mechanics (LEFM) on single edge notched bend (SENB) specimens. This study revealed that the fracture toughness of the reprocessed PLA was basically the same that the virgin PLA and also that the increase in the crystalline fraction produced an improvement on the fracture toughness, at slow loading rate.     

Degradation and environmental risk of surfactants after the application of compost sludge to the soil

In this work, the degradation of anionic and non-ionic surfactants in agricultural soil amended with sewage sludge is reported. The compounds analysed were: linear alkylbenzene sulphonates (LAS) with a 10-13 carbon alkylic chain, and nonylphenolic compounds (NPE), including nonylphenol (NP) and nonylphenol ethoxylates with one and two ethoxy groups (NP1EO and NP2EO). The degradation studies were carried out under winter (12.7°C) and summer (22.4°C) conditions in Andalusia region. The concentration of LAS was reduced to 2% of the initial concentration 100 day after sludge-application to the soil. The half-life time measured for LAS homologues were ranged between 4 and 14days at 12.7°C and between 4 and 7 days at 22.4°C. With regard to NPE compounds, after 8 and 4days from the beginning of the experiment at 12.7 and 22.4°C, respectively, their concentration levels were increased to 6.5 and 13.5mg/kgdm (dry matter) as consequence of the degradation of nonylphenol polyethoxylates. These concentration levels were reduced to 5% after 63 and 70 days for 12.7°C and 22.4°C, respectively. The half-life times measured for NPEs were from 8 to 16 days at 12.7°C and from 8 to 18 days at 22.4°C. Environmental risk assessment revealed that for LAS homologues no environment risk could be expected after 7 and 8 days of sludge application to the soil for 22.4 and 12.7°C, respectively; however, potential toxic effects could be observed for the nonylphenolic compounds during the first 56 days after sludge application to the soil.