Separation of polycarbonate and acrylonitrile–butadiene–styrene waste plastics by froth flotation combined with ammonia pretreatment

The objective of this research is flotation separation of polycarbonate (PC) and acrylonitrile–butadiene–styrene (ABS) waste plastics combined with ammonia pretreatment. The PC and ABS plastics show similar hydrophobicity, and ammonia treatment changes selectively floatability of PC plastic while ABS is insensitive to ammonia treatment. The contact angle measurement indicates the dropping of flotation recovery of PC is ascribed to a decline of contact angle. X-ray photoelectron spectroscopy demonstrates reactions occur on PC surface, which makes PC surface more hydrophilic. Separation of PC and ABS waste plastics was conducted based on the flotation behavior of single plastic. At different temperatures, PC and ABS mixtures were separated efficiently through froth flotation with ammonia pretreatment for different time (13 min at 23 °C, 18 min at 18 °C and 30 min at 23 °C). For both PC and ABS, the purity and recovery is more than 95.31% and 95.35%, respectively; the purity of PC and ABS is up to 99.72% and 99.23%, respectively. PC and ABS mixtures with different particle sizes were separated effectively, implying that ammonia treatment possesses superior applicability.     

Qualitative and quantitative determination of heavy metals in waste cellular phones

Twenty four waste cellular phones, manufactured between 2002 and 2011, were selected in order to determine the total heavy metal content in each of their parts (printed circuit boards (PCBs), plastic housing (PH) and liquid crystal display monitors (LCDs)) and compare the results with the permissible limits set by the 2003 Directive on Restriction of Hazardous Substances (RoHS). All the selected samples were pulverized and digested with strong acids. Inductively coupled plasma-mass spectrometry was used to measure the heavy metal content in each sample. The results revealed that concentration levels of the examined heavy metals were higher in PCBs, followed by PH and LCD in that particular order (PCB > PH > LCD). With the exception of Pb and Cr present in PCBs of mobile phones released before the year 2006, all the other metal concentrations were according to the Directive. Concentration levels of Cd, Hg were lower than the permissible limits set by the EU, either before or after the validity of the 2003 RoHS Directive. Considering their significant heavy metal content, coupled with their large quantities produced worldwide in an annual rate, waste cellular phones need to be treated under an environmentally sound management scheme, prioritizing recycling and at the same time eliminating the possibility of any harm.     

Cylinder cyclone (LARCODEMS) density media separation of plastic wastes

Cylindrical cyclone media separators using a suspended calcite separation media simulating industrial scale operations are demonstrated to effectively separate a wide variety of forms and a greater range of particle sizes of plastics by density than presently recycled. Purities of plastic products and recoveries obtained from mixed plastic wastes are comparable to those reported for established separations. Products of ≈100% purity with recoveries of >99% were obtained for high density fractions and >98% purities and recoveries for the low density fractions. Cyclonic centrifugal forces and/or the fine particle size of the separation media appear to minimize hydroscopic and particle shape effects.A mathematical model is proposed for defining plastic waste feed rates and treatable particle size ranges for the LARCODEMS media separator.Waste plastic separations yielded Ecart probable (Ep) values ?0.024 for a water only separation media. The Ep for 1.1 g cm^?3 separation medias was <0.032 with minimal to no variation in values for 1–8 mm particle sizes. Variation in the quality of separations is shown to be minimal with <72 μm, <45 μm and <2 μm media particle sizes. Media density offset created varied according to particle size.     

An analysis of the composition and metal contamination of plastics from waste electrical and electronic equipment (WEEE)

The compositions of three WEEE plastic batches of different origin were investigated using infrared spectroscopy, and the metal content was determined with inductively coupled plasma. The composition analysis of the plastics was based mainly on 14 samples collected from a real waste stream, and showed that the major constituents were high impact polystyrene (42 wt%), acrylonitrile–butadiene–styrene copolymer (38 wt%) and polypropylene (10 wt%). Their respective standard deviations were 21.4%, 16.5% and 60.7%, indicating a considerable variation even within a single batch. The level of metal particle contamination was found to be low in all samples, whereas wood contamination and rubber contamination were found to be about 1 wt% each in most samples. In the metal content analysis, iron was detected at levels up to 700 ppm in the recyclable waste plastics fraction, which is of concern due to its potential to catalyse redox reactions during melt processing and thus accelerate the degradation of plastics during recycling. Toxic metals were found only at very low concentrations, with the exception of lead and cadmium which could be detected at 200 ppm and 70 ppm levels, respectively, but these values are below the current threshold limits of 1000 ppm and 100 ppm set by the Restriction of Hazardous Substances directive.     

Metal toxicity assessment of mobile phone parts using Milli Q water

Environmentally safe disposal of end-of-life (EoL) or discarded mobile phone is a serious problem on account of their ever increasing number and toxic metals contents. In the present work, metal toxicity of mobile phone plastics, printed wire boards (PWBs) and batteries were assessed through dynamic batch leaching using Milli Q (MQ) water. Phone plastics failed Toxicity Characterization Leaching Procedure (TCLP) and Waste Extraction Test (WET) for Pb as the cumulative amount of Pb leached from plastics (5.33 mg/l) exceeded the regulatory limits (5.0 mg/l) used in characterizing a waste as hazardous. Similarly, the average cumulative amount (21.83 mg/l) of Ni leached from PWBs exceeded the regulatory limit of 20 mg/l and thus PWBs failed WET. Metals leached from batteries in small amounts (Cr: 0.40 mg/l and Ni: 0.15 mg/l). The presence of Fe in the batteries and its precipitation as oxides/hydroxides in the leaching solution hindered the leaching of other metals in MQ water. Both plastics and PWBs should be treated as hazardous waste and should not be disposed in open landfills. Further, MQ water leaching could provide good simulation of metals leaching from the mobile phones disposed at landfill sites.     

Removal of carbon constituents from hospital solid waste incinerator fly ash by column flotation

Hospital solid waste incinerator (HSWI) fly ash contains a large number of carbon constituents including powder activated carbon and unburned carbon, which are the major source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in fly ash. Therefore, the removal of carbon constituents could reduce PCDD/Fs in fly ash greatly. In this study, the effects of the main flotation parameters on the removal of carbon constituents were investigated, and the characteristics of the final product were evaluated. The results showed that loss on ignition (LOI) of fly ash increased from 11.1% to 31.6% during conditioning process. By optimizing the flotation parameters at slurry concentration 0.05 kg/l, kerosene dosage 12 kg/t, frother dosage 3 kg/t and air flow rate 0.06 m³/h, 92.7% of the carbon constituents were removed from the raw fly ash. Under these conditions, the froth product has LOI of 56.35% and calorific values of 12.5 MJ/kg, LOI in the tailings was below 5%, and the total toxic equivalent (TEQ) of PCDD/Fs decreased from 5.61 ng-TEQ/g in the raw fly ash to 1.47 ng-TEQ/g in the tailings. The results show that column flotation is a potential technology for simultaneous separation of carbon constituents and PCDD/Fs from HSWI fly ash.     

Steel slags in a landfill top cover – Experiences from a full-scale experiment

A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ?50 l (m² a)^?1 for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m² a)^?1 for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance.     

Transesterification of waste vegetable oil under pulse sonication using ethanol,methanol and ethanol–methanol mixtures

This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.     

Two-year performance by evapotranspiration covers for municipal solid waste landfills in northwest Ohio

Evapotranspiration (ET) covers have gained interest as an alternative to conventional covers for the closure of municipal solid waste (MSW) landfills because they are less costly to construct and are expected to have a longer service life. Whereas ET covers have gained acceptance in arid and semi-arid regions (defined by a precipitation (P) to potential evapotranspiration (PET) ratio less than 0.75) by meeting performance standards (e.g. rate of percolation), it remains unclear whether they are suitable for humid regions (P:PET greater than 0.75). The goal of this project is to extend their application to northwest Ohio (P:PET equals 1.29) by designing covers that produce a rate of percolation less than 32 cm yr^?1, the maximum acceptable rate by the Ohio Environmental Protection Agency (OEPA). Test ET covers were constructed in drainage lysimeters (1.52 m diameter, 1.52 m depth) using dredged sediment amended with organic material and consisted of immature (I, plants seeded onto soil) or mature (M, plants transferred from a restored tall-grass prairie) plant mixtures. The water balance for the ET covers was monitored from June 2009 to June 2011, which included measured precipitation and percolation, and estimated soil water storage and evapotranspiration. Precipitation was applied at a rate of 94 cm yr^?1 in the first year and at rate of 69 cm yr^?1 in the second year. During the first year, covers with the M plant mixture produced noticeably less percolation (4 cm) than covers with the I plant mixture (17 cm). However, during the second year, covers with the M plant mixture produced considerably more percolation (10 cm) than covers with the I plant mixture (3 cm). This is likely due to a decrease in the aboveground biomass for the M plant mixture from year 1 (1008 g m^?2) to year 2 (794 g m^?2) and an increase for the I plant mixture from year 1 (644 g m^?2) to year 2 (1314 g m^?2). Over the 2-year period, the mean annual rates of percolation for the covers with the M and I plant mixtures were 7 and 8 cm yr^?1, which are below the OEPA standard. The results suggest the application of ET covers be extended to northwest Ohio and other humid regions.     

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg^?1 dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg^?1 resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg^?1 feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered.     

Transportation fuel production by combination of LDPE thermal cracking and catalytic hydroreforming

Fuel production from plastics is a promising way to reduce landfilling rates while obtaining valuable products. The usage of Ni-supported hierarchical Beta zeolite (h-Beta) for the hydroreforming of the oils coming from LDPE thermal cracking has proved to produce high selectivities to gasoline and diesel fuels (>80%). In the present work, the effect of the Ni loading on Ni/h-Beta is investigated in the hydroreforming of the oils form LDPE thermal cracking. h-Beta samples were impregnated with Ni nitrate, calcined and reduced in H₂ up to 550 °C to achieve different Ni contents: 1.5%, 4%, 7% and 10%. Larger and more easily reducible metal particles were obtained on Ni 7%/h-Beta and Ni 10%/h-Beta. Hydroreforming tests were carried out in autoclave reactor at 310 °C, under 20 bar H₂, for 45 min. Ni content progressively increased the amount of gases at the expenses of diesel fractions, while gasoline remained approximately constant about 52–54%. Maximum selectivity to automotive fuels (～81%) was obtained with Ni 7%/h-Beta. Ni loading also enhanced olefins saturation up to Ni 7%/h-Beta. High cetane indices (71–86) and octane numbers (89–91) were obtained over all the catalysts. Regarding the different studied Ni contents, Ni 7%/h-Beta constitutes a rather promising catalyst for obtaining high quality fuels from LDPE thermal cracking oils.     

Impacts of industrial waste resources on maize (Zea mays L.) growth,yield, nutrients uptake and soil properties

Discharging untreated highly acidic (pH < 4.0), organic and nutrients rich monosodium glutamate wastewater (MW), and highly alkaline (pH > 10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5 ± 0.1) with PW and lime (treatments represented as MW + PW and MW + Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha^?1. Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear^?1 and 100-kernel weight were higher in MW + Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW + Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW + PW. The MW + PW and MW + Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.     

Application of dissolved air flotation on separation of waste plastics ABS and PS

The aim of this research was to separate waste plastics acrylonitrile butadiene styrene (ABS) and polystyrene (PS) by dissolved air flotation in a self-designed dissolved air flotation apparatus. The effects of wetting agents, frother, conditioning time and flotation time on flotation behavior of waste plastics ABS (w-ABS) and PS (w-PS) were investigated and the optimized separation conditions were obtained. The results showed that when using 25 mgL(-1) tannic acid, 5 mgL(-1) terpineol, 15 min conditioning time and 15 min flotation time, mixtures of w-ABS and w-PS were separated successfully by dissolved air flotation in two stages, the results revealed that the purity and recovery rate of w-PS in the floated products were 90.12% and 97.45%, respectively, and the purity and recovery rate of w-ABS in the depressed products were 97.24% and 89.38%, respectively. Based on the studies of wetting mechanism of plastic flotation, it is found that the electrostatic force and hydrophobic attraction cannot be the main factor of the interaction between wetting agent molecules and plastic particles, which can be completed through water molecules as a mesophase, and a hydrogen bonding adsorption model with hydration shell as a mesophase was proposed.     

Effect of nine years of animal waste deposition on profile distribution of heavy metals in Abeokuta,south-western Nigeria and its implication for environmental quality

Uncontrolled deposition of waste from animal farms is a common practice in south-western Nigeria, and the presence of heavy metals in soil constitutes environmental and health hazards by polluting the soil, ground water, adjoining streams and rivers. The study investigated the profile distribution of Mn, Pb, Cd, Zn, Fe, Cu, Ni and Cr in some tropical Alfisols in south-western Nigeria after nine years disposal of animal wastes. The amount of these metals in the soil horizons was high enough to cause health and phytotoxic risks. All the metals except Zn and Cr increased down the profile, while Mn, Pb, Cd, Fe, Cu and Ni accumulated at 80–120 cm depth. The increment of these metals at this depth over the top soil were 26%, 143%, 72%, 47%, 328% for Mn, Pb, Cd, Cu and Ni, respectively. It thus, shows their mobility and the possibility of polluting ground water. The Mn content at the poultry and cattle waste sites increased by 127% and 25%, respectively over the control, while that of cattle and swine dump site for Cd content were 9.82 and 15.63 mg kg^?1, respectively. Lead content also increased by 8.52 and 5.25 mg kg^?1, respectively.There was the accumulation of Zn and Cu at the swine dump site while the cattle dump site had the highest amounts of nickel and chromium. The least amount of Fe was recorded at the swine waste dump site. The reduction in organic matter with depths together with the reduced pH might have favored the mobility of the metals. The ranking of pollution among the sites was poultry > swine > cattle > sheep and could be due to the type of ration fed, the vaccination programmes, sanitation programmes and other management practices.     

Determination of total chlorine and bromine in solid wastes by sintering and inductively coupled plasma-sector field mass spectrometry

A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na₂CO₃ and ZnO and placed in an oven at 560 °C for 1 h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200 mg/kg for chlorine and 20 mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine.     

A comparative study of two composts as filter media for the removal of gaseous reduced sulfur compounds (RSCs) by biofiltration: Application at industrial scale

This work presents the use of two composts as filter media for the treatment by biofiltration of odors emitted during the aerobic composting of a mixture containing sewage sludge and yard waste. The chemical analysis of the waste gas showed that the malodorous compounds at trace level were the reduced sulfur compounds (RSCs) which were dimethyl sulfide (Me₂S), methanethiol (MeSH) and hydrogen sulfide (H₂S). Laboratory tests for biofiltration treatment of RSCs were performed in order to compare the properties of two filter media, consisted of a mature compost with yard waste (YW) and a mixture of mature compost with sewage sludge and yard waste (SS/YW). The maximum elimination capacity (EC) values obtained with the YW mature compost as packing material were 12.5 mg m^?3 h^?1 for H₂S, 7.9 mg m^?3 h^?1 for MeSH and 34 mg m^?3 h^?1 for Me₂S, and the removal efficiency decreased in the order of: H₂S > MeSH > Me₂S. Moreover, the YW compost filter medium had a better behavior than the filter medium based on SS/YW in terms of acclimation of the microbial communities and moisture content. According to these results, a YW mature compost as packing material for an industrial biofilter were designed and this industrial biofilter was found effective under specified conditions (without inoculation and addition of water). The results showed that the maximum EC value of RSCs was 935 mg m^?3 h^?1 (100% removal efficiency, RE) for an inlet loads (IL) between 0 and 1000 mg m^?3 h^?1. Thus, YW compost medium was proven efficient for biofiltration of RSCs both at laboratory and industrial scale.     

Microbial oxygen uptake in sludge as influenced by compost physical parameters

The wide range of optimal values reported for the physical parameters of compost mixtures suggest that their interactive relationships should be investigated. The objective of this study was to examine the microbial O₂ uptake rate (OUR) in 16 sludge waste recipes, offering a range of moisture content (MC), waste/bulking agent (W/BA) ratio and BA particle size levels determined using a central composite experimental design. The 3 kg samples were maintained at a constant temperature and aeration rate for 28 days, during which a respirometer recorded O₂ uptake to provide a measure of microbial activity and biodegradability. The cumulative O₂ consumption after 14 and 28 days was found to be significantly influenced by MC, W/BA ratio, BA particle size and the interaction between MC and W/BA ratio (p < 0.05). Using multivariate regression analysis, the experimental data was used to generate a model with good predictive ability for cumulative O₂ consumption after 28 days as a function of the significant physical variables (R² = 0.84). The prediction of O₂ uptake by the model depended highly on the interaction between MC and W/BA ratio. A MC outside of the traditional 50–60% (wet basis) range still resulted in a high level of microbial O₂ uptake as long as the W/BA ratio was adjusted to maintain a suitable O₂ exchange in the sample. The evolution of OUR in the samples was also investigated, uncovering strong associations between short and long-term respirometric indices, such as peak OUR and cumulative O₂ consumption (p < 0.005). Combining peak OUR data with cumulative O₂ consumption after 14 days allowed for accurate predictions of cumulative O₂ after 28 days of aeration (R² = 0.96), implying that future studies need only run trials up to 14 days to evaluate the overall O₂ consumption or biodegradability of similar sludge mixtures.     

Recovery of lithium and cobalt from waste lithium ion batteries of mobile phone

In view of the stringent environmental regulations, availability of limited natural resources and ever increasing need of alternative energy critical elements, an environmental eco-friendly leaching process is reported for the recovery of lithium and cobalt from the cathode active materials of spent lithium-ion batteries of mobile phones. The experiments were carried out to optimize the process parameters for the recovery of lithium and cobalt by varying the concentration of leachant, pulp density, reductant volume and temperature. Leaching with 2 M sulfuric acid with the addition of 5% H₂O₂ (v/v) at a pulp density of 100 g/L and 75 °C resulted in the recovery of 99.1% lithium and 70.0% cobalt in 60 min. H₂O₂ in sulfuric acid solution acts as an effective reducing agent, which enhance the percentage leaching of metals. Leaching kinetics of lithium in sulfuric acid fitted well to the chemical controlled reaction model i.e. 1 ? (1 ? X)^1/3 = k_ct. Leaching kinetics of cobalt fitted well to the model ‘ash diffusion control dense constant sizes spherical particles’ i.e. 1 ? 3(1 ? X)^2/3 + 2(1 ? X) = k_ct. Metals could subsequently be separated selectively from the leach liquor by solvent extraction process to produce their salts by crystallization process from the purified solution.     

Environmental analysis of a construction and demolition waste recycling plant in Portugal – Part I: Energy consumption and CO2 emissions

This work is a part of a wider study involving the economic and environmental implications of managing construction and demolition waste (CDW), focused on the operation of a large scale CDW recycling plant. This plant, to be operated in the Lisbon Metropolitan Area (including the Setúbal peninsula), is analysed for a 60 year period, using primary energy consumption and CO₂eq emission impact factors as environmental impact performance indicators.Simplified estimation methods are used to calculate industrial equipment incorporated, and the operation and transport related impacts. Material recycling – sorted materials sent to other industries, to act as input – is taken into account by discounting the impacts related to industrial processes no longer needed.This first part focuses on calculating the selected impact factors for a base case scenario (with a 350 tonnes/h installed capacity), while a sensitivity analysis is provided in part two. Overall, a 60 year global primary energy consumption of 71.4 thousand toe (tonne of oil equivalent) and a total CO₂eq emission of 135.4 thousand tonnes are expected. Under this operating regime, around 563 thousand toe and 1465 thousand tonnes CO₂eq could be prevented by replacing raw materials in several construction materials industries (e.g.: ferrous and non-ferrous metals, plastics, paper and cardboard).     

Recycling and reuse of waste from electricity distribution networks as reinforcement agents in polymeric composites

Of the waste generated from electricity distribution networks, wooden posts treated with chromated copper arsenate (CCA) and ceramic insulators make up the majority of the materials for which no effective recycling scheme has been developed. This study aims to recycle and reuse this waste as reinforcement elements in polymer composites and hybrid composites, promoting an ecologically and economically viable alternative for the disposal of this waste. The CCA wooden posts were cut, crushed and recycled via acid leaching using 0.2 and 0.4 N H₂SO₄ in triplicate at 70 °C and then washed and dried. The ceramic insulators were fragmented in a hydraulic press and separated by particle size using a vibrating sieve. The composites were mixed in a twin-screw extruder and injected into the test specimens, which were subjected to physical, mechanical, thermal and morphological characterization. The results indicate that the acid treatment most effective for removing heavy metals in the wood utilizes 0.4 N H₂SO₄. However, the composites made from wood treated with 0.2 N H₂SO₄ exhibited the highest mechanical properties of the composites, whereas the use of a ceramic insulator produces composites with better thermal stability and impact strength. This study is part of the research and development project of ANEEL (Agência Nacional de Energia Elétrica) and funded by CPFL (Companhia Paulista de Força e Luz).