A bulk of used paper supplied to recycling industry may contain water in their internal voids. This is because the price of the used paper is currently based on their weight and it has a huge potential of suppliers to add with water in order to increase the price. Currently used methods for detecting moisture content in a paper are restricted to a sheet of paper only. This paper presents a non-intrusive method for quick and in-situ measurement of water content in a bulk of used paper. The proposed method extends the capability of common paper moisture gauge, by using a neutron device. A fast neutron source (Am-Be 241) and a portable backscattering neutron detector are used for water measurement. It theoretically indicates that the slow neutron counts can be correlated to the hydrogen or water level in a paper. The method has the potential of being used by the paper-recycling industry for rapid and non-destructive measurement of water in a bulk of used paper.
There is an urgent need globally to find alternative sustainable steps to treat municipal solid wastes (MSW) originated from mismanagement of urban wastes with increasing disposal cost. Furthermore, a conglomeration of ever-increasing population and consumerist lifestyle is contributing towards the generation of more MSW. In this context, vermicomposting offers excellent potential to promote safe, hygienic and sustainable management of biodegradable MSW. It has been demonstrated that, through vermicomposting, MSW such as city garbage, household and kitchen wastes, vegetable wastes, paper wastes, human faeces and others could be sustainably transformed into organic fertiliser or vermicompost that provides great benefits to agricultural soil and plants. Generally, earthworms are sensitive to their environment and require temperature, moisture content, pH and sometimes ventilation at proper levels for the optimum vermicomposting process. Apart from setting the optimum operational conditions for the vermicomposting process, other approaches such as pre-composting, inoculating micro-organisms into MSW and redesigning the conventional vermireactor could be introduced to further enhance the vermicomposting of MSW. Thus the present mini-review discusses the potential of introducing vermicomposting in MSW management, the benefits of vermicomposted MSW to plants, suggestions on how to enhance the vermicomposting of MSW as well as risk management in the vermicomposting of MSW.
The effect of polypropylene maleic anhydride (PPMAH) on tensile properties and morphology of polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr)/ rice husk powder (RHP) composites has been studied. The composites were prepared through melt mixing at 180ºC for 9 minutes using 50 rpm rotor speed. The specimens were analyzed using different techniques, namely tensile test and Scanning Electron Microscopy (SEM). The results obtained showed that the tensile strength and Young’s modulus of the modified composites were increased, while the elongation at break showed the opposite trend as compared with the unmodified composites. The morphology results support the tensile properties and these indicated a better interaction between the filler and matrix with the presence of PPMAH as a compatibilizer.
In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.
Malaysia disposes of 28,500 tonnes of municipal solid waste directly into landfills daily. This fact alone necessitates sustainable landfills to avoid adverse impacts on the population and the environment. The aim of the present study was to elucidate the issues and challenges faced by waste managers in moving towards sustainable landfilling in Malaysia. Various factors influence the management of a landfill. Among them is the human factor, which includes attitude and public participation. Although Malaysia's economy is developing rapidly, public concern and awareness are not evolving in parallel and therefore participation towards sustainable waste management through the 'reduce, reuse and recycle' approach (3Rs) is severely lacking. Consequently, landfill space is exhausted earlier than scheduled and this is no longer sustainable in terms of security of disposal. Challenges also arise from the lack of funding and the increase in the price of land. Thus, most waste managers normally aim for 'just enough' to comply with the regulations. Investment for the establishment of landfills generally is minimized since landfilling operations are considered uneconomical after closure. Institutional factors also hamper the practice of sustainable landfilling in the country where 3Rs is not mandatory and waste separation is totally absent. Although there are huge obstacles to be dealt with in moving towards sustainable landfilling in Malaysia, recent developments in waste management policy and regulations have indicated that positive changes are possible in the near future. Consequently, with the issues solved and challenges tackled, landfills in Malaysia can then be managed effectively in a more sustainable manner.
This study employed contingent valuation method to estimate the willingness to pay (WTP) of the households to improve the waste collection system in Kuala Lumpur, Malaysia. The objective of this study is to evaluate how household WTP changes when recycling and waste separation at source is made mandatory. The methodology consisted of asking people directly about their WTP for an additional waste collection service charge to cover the costs of a new waste management project. The new waste management project consisted of two versions: version A (recycling and waste separation is mandatory) and version B (recycling and waste separation is not mandatory). The households declined their WTP for version A when they were asked to separate the waste at source although all the facilities would be given to them for waste separation. The result of this study indicates that the households were not conscious about the benefits of recycling and waste separation. Concerted efforts should be taken to raise environmental consciousness of the households through education and more publicity regarding waste separation, reducing and recycling.
The synthesis of fatty acid methyl esters (FAME) as a substitute to petroleum diesel was investigated in this study from crude jatropha oil (CJO), a non-edible, low-cost alternative feedstock, using aluminium modified heterogeneous basic oxide (Mg-Zn) catalyst. The transesterification reaction with methanol to methyl esters yielded 94% in 6h with methanol-oil ratio of 11:1, catalyst loading of 8.68 wt.% at 182°C and the properties of CJO fuel produced were determine and found to be comparable to the standards according to ASTM. In the range of experimental parameters investigated, it showed that the catalyst is selective to production of methyl esters from oil with high free fatty acid (FFA) and water content of 7.23% and 3.28%, respectively in a single stage process. Thus, jatropha oil is a promising feedstock for methyl ester production and large scale cultivation will help to reduce the product cost.
Waste plastics contain a substantial number of valuable chemicals. The wastes from post-consumer as well as from industrial production can be recycled to valuable chemical feedstock, which can be used in refineries and/or petrochemical industries. This chemical recycling process is an ideal approach in recycling the waste for a better environment. Polymer cracking using a laboratory fluidized bed reactor concentrated on the used highly contaminated catalyst, E-Cat 2. Even though E-Cat 2 had low activity due to fewer acid sites, the products yielded were similar with amorphous ASA and were far better than thermal cracking. The high levels of heavy metals, namely nickel and vanadium, deposited during their lifetime as an FCC catalyst, did not greatly affect on the catalyst activity. It was also shown that E-Cat 2 could be used with and without regeneration. Although there was more deactivation when there was no regeneration step, the yield of gases (C(2)-C(7)) remained fairly constant. For the first time, these results indicate that "waste" FCC catalyst (E-Cat) is a good candidate for future feedstock recycling of polymer waste. The major benefits of using E-Cat are a low market price, the ability to tolerate reuse and regeneration capacity.
Solid waste collection and disposal are among the most vital services provided to about 700 770 residents of the city of Erbil in northern Iraq. As such, proper waste management systems that consider both the quantity and composition of domestic solid waste are strongly required to address the increasing amount of solid waste. Unfortunately, these essential data are not easily available. The present study sought to gather data on the quantity and composition of domestic solid waste collected from different quarters in Erbil, and the feasibility of recycling these wastes. The solid waste generation rate (GR), uncompacted density, and weight percentages of combustible and incombustible materials were determined based on the collected materials (i.e., food, plastic, paper, metal, glass and cloth). The results show that the average GR and uncompacted density were 0.654 kg capita(-1) day(-1) and 175.72 kg m(-3), respectively. The weight percentages of food, plastic, paper, metal, glass, and cloth as components of domestic solid waste were 79.34, 6.28, 5.9, 3.6, 3.42 and 1.45%, respectively.
Paper recycling plants usually buy their raw material from suppliers. More than often, bulk used paper supplied to the plant contains some significant quantity of water in its internal voids. It may be included intentionally or unintentionally. The price of used paper depends on its weight, thus adding water will help to increase weight and consequently increase the price. In this way, plant owner who purchase the used paper suffers a significant of financial lost. The objectives of our experiment are to establish a calibration curve that correlate between the amount of neutron backscattered and water content, and finally to develop a correction factor that need to be introduced to the measured values of water content. A fast neutron source (Am-Be 241) and a portable backscattering neutron detector were used for water measurement. The experiments were carried out by measuring neutron backscattering from used paper that has been added with different amount of water. As a result, a neutron calibration curve that provides a correlation between neutron backscattering and water content was established.
In this study, poly(ethylene terephthalate) (PET) wastes bottle was recycled by glycolysis process using ethylene glycol. The unsaturated polyester resin (UPR) was then prepared by reacting the glycolysed product with maleic anhydride. The blend of UPR based on recycled PET wastes with liquid natural rubber (LNR) was carried out by varying the amount of LNR from 0 to 7.5 wt%. Mechanical tests such as tensile and impact were conducted to investigate the effects of LNR on the mechanical properties. Scanning Electron Microscopy (SEM) was used to analyze the morphology of the breaking area resulted from the tensile tests on the UPR and blend samples. From the results, the blend of 2.5 wt% LNR in UPR based recycled PET wastes achieved the highest strength in the mechanical properties and showed a well dispersed of elastomer particles in the sample morphology compared to other blends concentrations. This blend sample was then compared to the optimum blend of LNR with commercial resin through the glass transition temperature value Tg, mechanical strength and morphology properties. The comparison study showed that the Tg for UPR based recycled PET was higher than the value represented from commercial resin due to the degree of crystalinity in the molecular structure of the materials. LNR was found to be an effective impact modifier which gave a greater improvement in UPR from recycled PET wastes structure but not to the commercial one which needs 5% LNR to achieve the optimum properties. Thus, the compatibility between the UP resin based recycled PET and LNR was much better than with the commercial resin.
This study identifies the potential greenhouse gas (GHG) reductions, which can be achieved by optimizing the use of residues in the life cycle of palm oil derived biodiesel. This is done through compilation of data on existing and prospective treatment technologies as well as practical experiments on methane potentials from empty fruit bunches. Methane capture from the anaerobic digestion of palm oil mill effluent was found to result in the highest GHG reductions. Among the solid residues, energy extraction from shells was found to constitute the biggest GHG savings per ton of residue, whereas energy extraction from empty fruit bunches was found to be the most significant in the biodiesel production life cycle. All the studied waste treatment technologies performed significantly better than the conventional practices and with dedicated efforts of optimized use in the palm oil industry, the production of palm oil derived biodiesel can be almost carbon neutral.
An extractive fermentation technique was developed using a thermoseparating reagent to form a two-phase system for simultaneous cell cultivation and downstream processing of extracellular Burkholderia cepacia lipase. A 10% (w/w) solution of ethylene oxide-propylene oxide (EOPO) with a molecular mass of 3900 g/mol and pH 8.5, a 200 rpm speed, and 30 °C were selected as the optimal conditions for lipase production (55 U/ml). Repetitive batch fermentation was performed by continuous replacement of the top phase every 24h, which resulted in an average cell growth mass of 4.7 g/L for 10 extractive batches over 240 h. In scaling-up the process, a bench-scale bioreactor was tested under the conditions that had been optimized in flasks. The production rate and recovery yield were higher in the bioreactor compared to fermentation performed in flasks.
This paper examines the determinants of recycling behaviour among 200 university students from the perspective of the theory of planned behaviour (TPB). Data was analysed using Structural Equation Modelling technique. Findings indicate that environmental awareness was significantly related to attitude towards recycling, whilst attitude and social norms had significant impact on recycling behaviour. However, convenience and cost of recycling were not significant reasons for recycling. The study has enhanced the understanding of the determinants of recycling behaviour and has implications for schools and governmental agencies in educating and encouraging positive recycling behaviour. It also confirms the appropriateness of the TPB in examining studies of this nature. Further suggestions for future research are offered.
The objectives of this study were: (1) to investigate the role of mixed culture of biomass in the regeneration of mono-amine modified silica (MAMS) and granular activated carbon (GAC) loaded with Acid Orange 7 (AO7), (2) to quantify and compare the bioregeneration efficiencies of AO7-loaded MAMS and GAC using the sequential adsorption and biodegradation approach and (3) to evaluate the reusability of bioregenerated MAMS. The results show that considerably higher bioregeneration efficiency of AO7-loaded MAMS as compared to that of AO7-loaded GAC was achieved due to higher reversibility of adsorption of MAMS for AO7 and favorable pH factor resulting in more AO7 desorption. The progressive loss of adsorption capacity of MAMS for AO7 with multiple cycles of use suggests possible chemical and microbial fouling of the adsorption sites.
The ageing of the bitumen during storage, mixing, transport and laying on the road, as well as in service life, are the most important problems presented by the use of bitumen in pavements. This paper investigates the possibility of using waste cooking oil (WCO), which is a waste material that pollutes landfills and rivers, as an alternative natural rejuvenating agent for aged bitumen to a condition that resembles the original bitumen. With this target, the physical and chemical properties of the original bitumen, aged bitumen and rejuvenated bitumen were measured and compared by the bitumen binder tests - softening point, penetration, Brookfield viscosity, dynamic shear rheometer and Fourier transform infrared spectroscopy. In addition, the behaviour of the WCO rejuvenated bitumen is investigated and compared with virgin bitumen after using the rolling thin film oven ageing process. In general, the results showed that using 3-4% of WCO the aged bitumen group 40/50 was rejuvenated to a condition that closely resembled the physical, rheological properties of the original bitumen (80/100), however, there was a difference in the tendency to ageing between the WCO rejuvenated bitumen and the virgin bitumen during mixing, transport and laying on the road.
Fe-doped titanium dioxide (TiO(2)) nanotubes were prepared using sol-gel followed by hydrothermal methods and characterized using various methods. The sonocatalytic activity was evaluated based on oxidation of Rhodamine B under ultrasonic irradiation. Iron ions (Fe(3+)) might incorporate into the lattice and intercalated in the interlayer spaces of TiO(2) nanotubes. The catalysts showed narrower band gap energies, higher specific surface areas, more active surface oxygen vacancies and significantly improved sonocatalytic activity. The optimum Fe doping at Fe:Ti=0.005 showed the highest sonocatalytic activity and exceeded that of un-doped TiO(2) nanotubes by a factor of 2.3 times. It was believed that Fe(3+) doping induced the formation of new states close to the valence band and conduction bands and accelerated the separation of charge carriers. Leached Fe(3+) could catalyze Fenton-like reaction and led to an increase in the hydroxyl radical (OH) generation. Fe-doped TiO(2) nanotubes could retain high degradation efficiency even after being reused for 4 cycles with minimal loss of Fe from the surface of the catalyst.
Cu(II) removal efficacies of alginate-immobilized Trichoderma asperellum using viable and non-viable forms were investigated with respect to time, pH, and initial Cu(II) concentrations. The reusability potential of the biomass was determined based on sorption/desorption tests. Cu(II) biosorption by immobilized heat-inactivated T. asperellum cells was the most efficient, with 134.22mg Cu(II) removed g(-1) adsorbent, compared to immobilized viable cells and plain alginate beads (control) with 105.96 and 94.04mg Cu(II) adsorbed g(-1) adsorbent, respectively. Immobilized non-viable cells achieved equilibrium more rapidly within 4h. For all biosorbents, optimum pH for Cu(II) removal was between pH 4 and 5. Reusability of all biosorbents were similar, with more than 90% Cu(II) desorbed with HCl. These alginate-immobilized cells can be applied to reduce clogging and post-separation process incurred from use of suspended biomass.
This article presents lessons learned from a design project that explored the possibility of incorporating waste into the design of a school prototype. The authors worked with professional architects, a waste artist, environmental scientists and local waste operators to uncover new uses and applications for discarded items. As a result, bottles, aluminium cans, reclaimed doors, crushed concrete and second-hand bricks, etc. were identified, explored and integrated into the architectural design. This article serves as a catalyst that advocates the use of reclaimed materials in the field of design and planning. In particular, it highlights the challenges and issues that need to be addressed in carrying out design work with waste. Designers and practitioners interested in minimizing waste generation by proposing the use of reclaimed materials will find this article useful.