Disposal Techniques Research Articles

Investigation of the occurrence characteristics of organic components in high-sulfur waste residues (HSWR)

High-sulfur waste residues (HSWR) is a typical byproduct produced in the printing and dyeing industry that has hazardous properties, such as flammability and reactivity, etc. It is of great significance for the directional and harmless treatment of waste residues in the later stage on the research in-depth of the occurrence characteristics of each component in HSWR. In this paper, the combinatorial analysis method is employed to perform in-depth research on the phase composition, surface chemical situation of element, and the occurrence state of functional groups of the waste residue from multiple perspectives. The results show that the organic and inorganic components in HSWR are intricately interwoven, and exhibit significant thermal instability at high temperatures, with a maximum weight less of 86.66%. Carbon mainly exists in the states of C-H/C-OH/C-C, C-O/C-NH2, and C=O/C-N/C-S/CHx and constitutes the main chain of the carboxylic ring. Sulfur mainly occurs in three forms, namely, amorphous aggregated sulfur, sulfur-containing inorganic salts such as sulfate, and nitrogen-heterocyclic organic compounds containing sulfhydryl groups and methyl sulfur groups. These organic compounds constitute branch chains of the organic phase, and combine with metal cations through hydroxyl or carboxyl groups, and deposit on the surface of inorganic agglomerated sulfur. This wrapping structure increases the stability of volatile compounds in the slag and increases the difficulty of sulfur and chlorine removal. These findings provide a material basis for the later development of safe and effective HSWR disposal techniques.

Mapping of a Novel Zero-Liquid Discharge Desalination System Based on Humidification–Dehumidification onto the Field of Existing Desalination Technologies

It is well-established that increasing demands for fresh water are paving the way for desalination technologies. However, this correlates with an increase in brine production whose treatment and disposal can be complicated and expensive. This paper presents a thermodynamic model to bound the operation and development of a novel Humidification–Dehumidification-based system featuring Zero-Liquid Discharge and off-grid capabilities. The model employs conservation laws to find feasible state points to meet a baseline operation of 10 kg/h of product water separated from a hypersaline feed stream with 100 g/kg salt concentration. The system incurs in a 1039 kWh/m3 energy intensity that can be supplied completely by an electric source or in combination with heating steam. Follow-up sensitivity analysis highlights the robustness of the system in handling variations of 25% in product flowrate and 75% in feed salinity, practically without incurring any additional energy demands. The proposed system operating costs between 72 USD/m3 and 96 USD/m3 are comparable to those of existing brine disposal techniques. Furthermore, an operational map of existing desalination technologies suggests a niche characterized by high recovery rates and high feed salinities that are generally unfulfilled by conventional desalination methods. Overall, the proposed system shows potential for off-grid hypersaline brine treatment. This study sets the stage for future development of physics-based and data-driven predictive models as the proposed system iterates into a pilot plant deployment.

Supramolecular Self-Assembly Strategy towards Fabricating Mesoporous Nitrogen-Rich Carbon for Efficient Electro-Fenton Degradation of Persistent Organic Pollutants.

The electro-Fenton (EF) process is regarded as an efficient and promising sewage disposal technique for sustainable water environment protection. However, current developments in EF are largely restricted by cathode electrocatalysts. Herein, a supramolecular self-assembly strategy is adopted for synthetization, based on melamine–cyanuric acid (MCA) supramolecular aggregates integrated with carbon fixation using 5-aminosalicylic acid and zinc acetylacetonate hydrate. The prepared carbon materials characterize an ordered lamellar microstructure, high specific surface area (595 m2 g−1), broad mesoporous distribution (4~33 nm) and high N doping (19.62%). Such features result from the intrinsic superiority of hydrogen-bonded MCA supramolecular aggregates via the specific molecular assembly process. Accordingly, noteworthy activity and selectivity of H2O2 production (~190.0 mg L−1 with 2 h) are achieved. Excellent mineralization is declared for optimized carbon material in several organic pollutants, namely, basic fuchsin, chloramphenicol, phenol and several mixed triphenylmethane-type dyestuffs, with total organic carbon removal of 87.5%, 74.8%, 55.7% and 54.2% within 8 h, respectively. This work offers a valuable insight into facilitating the application of supramolecular-derived carbon materials for extensive EF degradation.

Measuring the Economic Value of the Negative Externality of Livestock Malodor in South Korea

The South Korean livestock industry has increased in scale and production, generating positive impacts on the national economy. However, livestock externalities, primarily malodor, have subsequently led to increased conflicts between producers and affected communities. This study estimated Korean households’ willingness-to-pay (WTP) for government subsidies to help address livestock malodor using a contingent valuation method (CVM) derived from a double-bounded dichotomous choice model. The annual average household WTP was estimated at 29,206 Korean won (KRW) (USD 25). This was slightly higher than the respondents’ self-reported average amount of KRW 25,457 (USD 22). The estimated economic value nationally is KRW 628 billion (USD 546 million) annually, for a total of KRW 3.14 trillion (USD 2.73 billion) over a proposed five-year period. The public’s estimated WTP can be leveraged to improve livestock management practices, more efficient waste disposal techniques, and improved husbandry methods to address conflicts between producers and surrounding communities.

The face behind the Covid-19 mask - A comprehensive review.

The threat of epidemic outbreaks like SARS-CoV-2 is growing owing to the exponential growth of the global population and the continual increase in human mobility. Personal protection against viral infections was enforced using ambient air filters, face masks, and other respiratory protective equipment. Available facemasks feature considerable variation in efficacy, materials usage and characteristic properties. Despite their widespread use and importance, face masks pose major potential threats due to the uncontrolled manufacture and disposal techniques. Improper solid waste management enables viral propagation and increases the volume of associated biomedical waste at an alarming rate. Polymers used in single-use face masks include a spectrum of chemical constituents: plasticisers and flame retardants leading to health-related issues over time. Despite ample research in this field, the efficacy of personal protective equipment and its impact post-disposal is yet to be explored satisfactorily. The following review assimilates information on the different forms of personal protective equipment currently in use. Proper waste management techniques pertaining to such special wastes have also been discussed. The study features a holistic overview of innovations made in face masks and their corresponding impact on human health and environment. Strategies with SDG3 and SDG12, outlining safe and proper disposal of solid waste, have also been discussed. Furthermore, employing the CFD paradigm, a 3D model of a face mask was created based on fluid flow during breathing techniques. Lastly, the review concludes with possible future advancements and promising research avenues in personal protective equipment.

Effect of Gypsum Waste Inclusion on Gasification of Municipal Solid Waste

Abstract Sustainable disposal techniques of municipal solid wastes (MSW) are essential for effective materials recovery and energy management. Synergistic incorporation of gypsum waste from the construction and demolition (C&D) sector is explored here for the low techno-economic viability of MSW in waste-to-energy facilities. Co-processing of MSW with this low-value gypsum can potentially provide improved product recovery and simultaneously furnish economic viability. To understand the impact of gypsum incorporation into MSW conversion, we tested synthetic MSW and a 1:1 mixture of MSW with gypsum from drywall wastes and compared their micro-scale mass loss kinetics along with macro-scale syngas evolution and conversion at different temperatures, and in pyrolytic and oxidizing environments. Gypsum incorporation led to increased syngas production and decreased char yields as the char was oxidized by CaSO4. Thermogravimetric analysis (TGA) revealed two different temperature zones of gypsum interaction with MSW depending on the oxidation concentration in the environment. Adding 50% gypsum only changed the final ash yield by 10% in pyrolysis conditions suggesting the viability of gypsum incorporation. While the addition of gypsum led to delayed evolution of H2 and CO, the cumulative yields of H2 and CO2 increased significantly and the yield of CO changed minimally. Additionally, hydrocarbon by-products such as CH4 decreased by gypsum addition. The results showed improved syngas yield and uniformity, as well as operational conditions from the gypsum interaction with MSW which can help in the further development of gypsum waste incorporation.

Overall Review on Current scenario in Waste Management System

There are several concerns with the management of pharmaceutical waste. In this paper we included types of waste, regulatory bodies involved in management of waste material and waste management strategy. Because of the dangers, pharmaceutical waste cannot be disposed of like conventional waste and requires special handling, whether it comes from a hospital, clinic, pharmacy, or private household. A waste product may become a by-product, joint product or resource through an invention that raises a waste product's value above zero. Pharmaceutical waste is a form of medical waste that includes unused medications, over-the-counter personal care products, and sometimes accessories such as sharps, used test strips, and other supplies. In order to safely handle and dispose of waste it is necessary to understand the specific hazards of the waste product, and the ability of a given disposal technique to manage them. Examples include municipal solid waste (household trash/refuse), hazardous waste, wastewater (such as sewage, which contains bodily wastes (feces and urine) and surface runoff), radioactive waste, and others.

Ecotoxicity Studies for On-Site Disposal of Decant Water During Oil Spills: A Review

Mechanical oil recovery, a most used tool for oil spill response, can generate a considerable proportion of oil-contaminated water (10–70%). Large storage space is commonly required to transport the recovered oil and water mixture to shore. Transit and transportation consume loads of time, money, and resources while reducing oil recovery’s overall efficiency and capacity. Techniques of on-site treatment and disposal of oily wastewater provide benefits for oil recovery by freeing storage space. However, the high petroleum content of decant water can lead to uncertain risks, if discharged into the marine ecosystem. Insufficient ecological toxicity data and research limit the standardization and establishment of regulative tools. To fill the knowledge gaps, this review comprehensively summarized recent studies on the potential impacts of the organic composition in decant water, including oil–water accommodated fractions, dispersed oil droplets, and other related chemicals, on various marine species (i.e., bacterium, invertebrates, fishes, plants, reptiles, and mammals). The toxicity effects and the ecological endpoints of oils, TPH, and PAHs on different species were discussed. Recommendations for future ecological impacts and decant water composition were provided to support the on-site disposal of the water fraction.

Fe, Co, N co-doped hollow carbon capsules as a full pH range catalyst for pollutant degradation via a non-radical path in Fenton-like reaction

Persulfate (PMS)-based Fenton-like reaction was a highly efficient technique for disposal of organic contaminants. However, high metal leaching and low environmental adaptation were the major concerns for further application. To overcome these two drawbacks, herein, Fe, Co, N atoms co-doped hollow carbon capsules (Fe-Co-N@HCCs) were prepared and used as catalysts for PMS activation. 92.6% of TC was degraded within 40 min and the mineralization efficiency was 55.7%. The degradation rate was 4.7, 3.1 and 1.4 times higher than those of activated carbon, N@HCCs, and Fe-N@HCCs, respectively. Thermodynamic study indicated the TC degradation was an exothermal, chaotic and non-spontaneous process. Radical trapping experiments, electron paramagnetic resonance spectrum, and electrochemical analysis indicated that 1O2 production and electron-transfer path worked together for PMS activation. DFT calculation indicated that the catalytic activity of Co-N4 site was higher than Fe-N4 site for 1O2 production. Fe-Co-N@HCCs were adapted well to the full pH range (0–14) and complex inorganic anions via non-radical PMS activation paths. Meanwhile, the leached Fe and Co ions were lowered to 0.201 and 0.457 mg/L, satisfying the China emission standard. This work gave a better comprehension on preparation of carbonaceous materials with high environmental adaptation and low leached metal ions for PMS activation.

Performance of Glass and Steel Slag Mixtures as a Partial Replacement for Fine Aggregate in Asphalt Concrete

Solid waste management is a significant challenge particularly in developing countries for example Nigeria. The waste disposal technique is inadequate as negative effects from improper solid waste dumping can be easily visible in the environment. Recycling and reuse of wasteas aggregate in asphalt production may be an economic way to reduce these problems. This research evaluates the viability of crushed waste glass combined with steel slag (GSS) as fine aggregate in asphalt wearing courses. The Marshall mix method was used in production and evaluation of samples. GSS mixtures in the ratio 70:30 (steel slag: glass) were substituted for fine aggregate at varying percentages of 0 to 50 %. This mix ratio was adopted so that the glass content does not exceed 10%.Five samples of GSS content (10%, 20%, 30%, 40%and 50%) were prepared and their Marsha lstability,Voids in Mineral Aggregates, Voids filled with Bitumen and bulk density were evaluated and compared to nominal asphalt mix. While a 10% GSS replacement in modified asphalt resulted in a greater peak stability value of 16.21 kN compared to the standard mix peak stability value of 12.68kN. The 20% GSS replacement resulted in a lower flow value and a significantly higher Marshall quotient of 5.11KN/MM was recorded at 20% replacement, making it preferable. As a result, a 20% replacement is advised for heavily trafficked highways, whereas up to 30% replacement is permissible on lightly traveled roads.

Pyrolysis of exhausted hydrochar sorbent for cadmium separation and biochar regeneration

Sorption is considered a cost-effective technique for cadmium (Cd) removal from water, while the exhausted Cd-enriched sorbent should be properly disposed of. In this study, pyrolysis of exhausted hydrochar sorbent was conducted at 300–900 °C, and the behavior of Cd and the physicochemical properties and environmental applications of the regenerated biochar were investigated. The vaporization of adsorbed Cd in hydrochar was greatly enhanced by elevating pyrolysis temperature, and almost no Cd was observed in the regenerated biochars obtained at 700–900 °C. In comparison with the raw hydrochar, the regenerated biochars showed higher pH, ash content, and carbon content, while the contents of hydrogen and oxygen decreased. According to the toxicity characteristic leaching procedure result, the toxicity and mobility of Cd in hydrochar were greatly reduced after pyrolysis. Notably, the regenerated biochar showed much higher Cd sorption capacity (26.05–30.24 mg/g) than the raw hydrochar (6.70 mg/g). Surface complexation with oxygen-containing functional groups was the dominant Cd sorption mechanism for hydrochar, and precipitation between Cd2+ and carbonates dominated the Cd removal by the regenerated biochars. These results illuminated that pyrolysis can be an effective technique for the harmless disposal of exhausted hydrochar sorbent and the regeneration of valuable biochar.

Examination of Menstrual Waste Disposal Techniques used by the Millennials in Sri Lanka

Menstrual waste (MW) disposal practices are not subjected to discussion in many Asian countries and religious beliefs/norms have created misleading perceptions putting females at risk of being stigmatized. Therefore, the disposal techniques used in such countries can harm the environment irrespective of the education levels of the people due to their attempts in hiding the traces of menstrual blood. This paper is mainly aimed at discussing the MW disposal techniques and Menstrual Hygiene Management (MHM) techniques used by the millennials in Sri Lanka. As a secondary objective, this study evaluates whether the MW disposal technique used by the respondent is stressful to her and the effect of education level on it. 52.1% of the Sri Lankan population is female and the current study considered the millennials. Due to the social stigma that comes with menstruation, referrals were used to engage responders and the snowball sampling technique was used. A self-developed questionnaire was distributed and the Pearson's Chi-square Goodness-of-fit and Rank Biserial Correlation were used along with Estimated Population Proportions (EPP). Of the 150 respondents, 52% use burning (open), 18% throw-in routine waste bins, 8.7% throw with proper grading and 8% use toilet pits to dispose of their MW. The remaining respondents used incinerators, washing or dumped/burned waste in open areas such as land, rivers etc. The chi-square goodness-of-fit test indicated that each of the disposal methods was not equally represented by the respondents (χ2(7)=586.903, p=0.0001), with just over half of the respondents using open burning as the method of disposal. Commercial sanitary pads and reusable/washable sanitary pads were the only techniques reported for MHM. The majority of the respondents reported the use of commercial sanitary pads and the EPP was 0.93±0.042. The majority of the respondents reported feeling stressed due to their method of disposal. There was a positive correlation between the status of stress and education level, which was statistically significant (rpb=0.178, p=0.003). Based on the above-said results, burning inorganic materials such as commercial sanitary pads at low temperatures release dioxins that are poisonous and carcinogenic, leaving an impact on both health and the environment. Hence, it is recommended to introduce more environment-friendly absorption materials such as reusable sanitary items made of easily decomposed materials and to implement proper incineration facilities. When considering the negative impact on the environment, educating the Sri Lankan female population on better disposal practices can be identified as a necessity.
 Keywords: Menstrual waste, Waste disposal, Millennials, Menstrual hygiene management, Stress

Waste Generation and Characteristics in Sri Lankan Textile and Apparel Sector: Case Study of the Biyagama Industrial Export Processing Zone, Sri Lanka

The main goal of the study was to look at the properties of waste, treatment options, and disposal techniques. Furthermore, waste circulation variables in the textile and apparel sectors in Sri Lanka’s Biyagama Industrial Processing Zone were calculated. The types, volumes, and per capita waste generation of ten industries were analyzed, as well as waste management activities such as trash minimization, handling, storing, recirculation, and disposal. The information was gathered using questionnaires, interviews, and field observations. According to the findings, the total industrial waste generation rate was 13792.5 tonnes per year, with 5926 tonnes per year designated as hazardous waste materials (42.9%). Furthermore, the waste generation rate per capita was 0.93 kg. The waste circulation factor was 0.38, according to the findings. The findings of the study highlight the necessity for integrated waste management methods in the textile and apparel industries.

A review of end-life management options for marine structures: State of the art, industrial voids, research gaps and strategies for sustainability

End-of-life management for marine structures demands exceptionally sustainability practices due to the potential for environmental and health hazards associated. The purpose of this article is to explain how improved recycling, reusing, and disposal techniques contribute to the marine industry's long-term sustainability. The subject is narrated through six major maritime structural material categories: ferrous, non-ferrous, polymer, inorganic materials, composites, and concrete. With the information gathered, some noticeable institutional voids were identified and discussed with the possible actions to counter them. Environmental sustainability, economic concerns, waste management, and a lack of regulatory execution were identified as critical global issues. It is stressed that the design requirements for marine structures should consider (a) the overall benefits and drawbacks of end-of-life options, as well as (b) the marine structure's lifecycle cost. When adopting design for reuse/recycle concepts, the proposed three-phase design hierarchy would be a valuable tool for structural designers. The degree of sustainability of various end-of-life management solutions is graded using a ranking system. With more research, the ranking system can be developed into a standardised rating model. Overall, the study covers state of the art in the end-of-life management industry and outlines significant global concerns and research gaps while offering answers and techniques for dealing with such issues, ensuring the industry's long-term sustainability. • Marine structures are pulled out of service and disposed of at the end of their lifetimes. • Different end-life management options are discussed for five material categories. • Design for reuse/recycle concept is vital for the sustainability in end-life management. • Poposed design hierarchy aid the adoption of design for reuse/recycle concept. • Proposed rating system aids to choose the best end-life management option.

Influence of magnetite incorporation into chitosan on the adsorption of the methotrexate and in vitro cytotoxicity.

Emerging pollutants are a group of substances involved in environmental contamination resulting mostly from incomplete drug metabolism, associated with inadequate disposal and ineffective effluent treatment techniques. Methotrexate (MTX), for instance, is excreted at high concentrations in unchanged form through the urine. Although the MTX is still effective in cancer and autoimmune disease treatment, this drug shows the ability of bioaccumulation and toxicity to the organism. Thus, the present work aimed to evaluate the adsorption of the MTX drug onto magnetic nanocomposites containing different amounts of incorporated magnetite (1:1, 1:5, and 1:10 wt%), combining the theoretical-experimental study as well as the in vitro cytotoxicity. Moreover, equilibrium studies (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Hill, Redlich-Peterson, and Sips), kinetic (PFO, PSO, and IPD), and thermodynamic (ΔG°, ΔH°, and ΔS°) were used to describe the experimental data, and ab initio simulations were employed in the theoretical study. Magnetic nanocomposites were synthesized by the co-precipitation method using only FeCl2 as the iron precursor. Adsorbents were characterized by FTIR, XRD, Raman, SEM-EDS, BET, and VSM analysis. Meanwhile, cytotoxic effects on L929 and A375 cell lines were evaluated through MTT, NR, and LDH assays. The adsorption of the MTX was carried out in a typical batch system, exploring the different experimental conditions. The theoretical study suggests the occurrence of chemisorption between CS·Fe3O4-MTX. The maximum adsorption capacity of MTX was 285.92mgg-1, using 0.125g L-1 of CS·Fe3O4 1:1, with an initial concentration of the MTX (50mg L-1), pH 4.0 at 293 ± 1.00K. The best adjustment of equilibrium and kinetic data were the Sips (low values for statistical errors) and PSO (qe = 96.73mgg-1) models, respectively. Thermodynamic study shows that the adsorption occurred spontaneously (ΔG° < 0), with exothermic (ΔH° = - 4698.89kJmol-1) and random at the solid-solution interface (ΔS° = 1,476,022.00kJmol-1k-1) behavior. Finally, the in vitro study shows that magnetic nanomaterials exhibit higher cytotoxicity in melanoma cells. Therefore, the magnetic nanocomposite reveals to be not only an excellent tool for water remediation studies but also a promising platform for drug delivery.

Long-Term Orbit Prediction and Deorbit Disposal Investigation of MEO Navigation Satellites

With the increase in satellites in the medium Earth orbit (MEO) region, there should be a focus on orbit safety in the MEO region. A safe orbit disposal strategy is necessary to maintain the sustainability of the MEO region. This paper focuses on long-term evolution modeling, safety analysis of MEO objects, and different disposal techniques for end-of-life BDS-2 MEO satellites. On the one hand, a long-term numerical evolution model is established, and mean equinoctial elements are adopted to propagate a long-term orbit. Long-term evolution for the MEO region over 100 years is carried out, including the Galileo, BDS, GPS, and GLONASS constellations. The earliest orbit intersection time with other global navigation satellite system (GNSS) constellations is put forward. On the other hand, a dynamic model and an optimization model for disposal orbit are established, which minimize the eccentricity growth within 200 years and the fuel consumption for maneuvering to the disposal orbit. The bounds for the disposal region of BDS MEO satellites are also proposed, which consider the measurement and control error of BDS MEO satellites and the eccentricity bounds for end-of-life BDS MEO satellites. A genetic algorithm is adopted to optimize the orbital elements for end-of-life BDS MEO satellites. In addition, two disposal cases, namely, upraising and reducing the orbit, for end-of-life BDS MEO satellites are simulated. The long-term evolutions for the disposal of orbital elements within 200 years are implemented, and the fuel consumption is calculated. The results show that the current MEO region is relatively safe and that the eccentricity is the most important factor that influences the long-term evolution of safety analysis for BDS MEO disposal orbits. Upraising the orbit is safe for end-of-life BDS MEO satellites. This investigation provides the theoretical foundation for investigating the long-term evolutionary mechanisms of the MEO region and references disposal strategy analysis for decommissioned navigation satellites, and the spent upper stages for other GNSS constellations.

A Review on the Treatment of Petroleum Sludge and Use as Construction Materials

Petrochemical is a vital pillar industry for the national economic growth wherein the past few years, it has produced a huge amount of petroleum sludge. Petroleum sludge (PS) contains toxic and carcinogenic-mutagenic compounds and heavy metals, which are a major source of pollution in the environment. Thus, it needs to be properly treated and disposed of. Correspondingly, this paper presents a review of the techniques to treat petroleum waste to effectively immobilize the heavy metals and highlights their possible application as construction materials. This review concludes that each treatment method (i.e., solidification, stabilization, incineration, bioremediation, centrifugation, etc.) has its own merits and demerits and may be more suitable for certain applications than others. The use of pyrolysis, solidification, and stabilization techniques has been demonstrated to be potentially beneficial in protecting the environment from contaminants in PS and further recycling PS as cementitious materials. However, the selection of suitable treatment methods has to be made based on the chemical composition of the waste, method capacity, costs, and disposal standards. Therefore, an overall evaluation is required prior to treatment method selection to ensure the safe disposal or recycling of petroleum waste. This review could improve basic knowledge of PS treatment and disposal techniques and serve as a future guide for recycling PS as a building material.

On the Issue of Air Emissions Control for Sewage Sludge Incinerators: A Short Review

Introduction: More than 100 million cubic meters of sewage sludge are accumulated annually at municipal wastewater treatment facilities of the Russian Federation. Its quantity depends on sewage treatment techniques while its qualitative composition is determined by the components of wastewater, efficiency of treatment facilities, and local industries. Sewage sludge contains toxic substances (heavy metal salts, toxic organic matter, etc.) and various types of microorganisms including pathogenic bacteria, all posing hazards to human health and environment. Objective: To summarize and systematize information about fluidized bed incineration of sewage sludge and to compile the list of pollutants emitted by incinerators and subject to control in ambient air. Materials and methods: We used data analysis methods based on review and summarization of up-to-date research data found in Scopus, PubMed, and RSCI abstract and citation databases for 2021–2022. The article selection criterion included the presence of information about effective techniques of sewage sludge disposal. Having reviewed 40 articles, we selected 30 appropriate full-text publications on the topic. Results: We established that incineration is considered to be an effective and universal contemporary method of reducing a large amount of sewage sludge and generating energy. Conclusion: Compared to other techniques of thermal treatment, sewage sludge incineration is promising in terms of equipment and techniques. However, more attention shall be paid to the mechanism of incineration, equipment, temperature conditions, and other factors affecting generation of pollutants, as well as to control of air emissions from sewage sludge incinerators at wastewater treatment plants.

A study on biofuel produced from cracking of low density poly ethylenes using TiO2/AlSBA-15 nanocatalysts

The burgeoning concerns over the non-biodegradable plastics wastes could be surpassed either by proper disposal technique or by an effective conversion of the plastic wastes into useful chemicals. Metal oxide; TiO2 and porous; AlSBA-15 catalysts were synthesized and a composite characterized using XRD, BET, N2 adsorption –desorption studies, TPD and SEM techniques. This work was focussed in the catalytic degradation of low density polyethylene over the synthesized catalysts in a fixed bed reactor. A hydrocarbon rich gasoline range of liquid fuel, coke and gas were the expected products from the experiment. The liquid products were analysed using GC MS equipped with J&W Scientific DB-Petro capillary column (100 m × 0.25 mm × 0.5 m). An optimum yield of liquid fuel was obtained with TiO2 catalyst at 1st h of reaction and further the product yield considerably decreased. A marginal increase in % conversion of low density polyethylene into fuel was observed with increasing catalyst: polymer ratio in the presence of TiO2 catalyst till 1:5 ratio. The liquid products contained lower range of hydrocarbons with higher content of active catalyst; while the samples collected at later stage contained heavier components. Mesoporous AlSBA-15 worked comparatively better than TiO2 by converting 89.7% of LDPE into 54.8% combustible liquid products. The catalytic activity of the catalyst followed the order of TiO2/AlSBA-15 (10%) < AlSBA-15 (27) < SiSBA-15 < TiO2. A considerable increase in gasoline fraction from 45.6% to 85.4%, yield of liquid fuel (89.1%) and conversion (98.4%) was observed during cracking in the presence of TiO2/AlSBA-15 catalyst. Plastic liquid fuel produced over the composite catalyst revealed the calorific value of 47.8 MJ/Kg which was higher than the commercial petroleum fuel. Finally, we obtain this biofuel application as mathematical model to evaluate and plot the interaction energy arising from the conjugation of TiO2 - AlSBA-15 nano-catalyst in two possible configuration, linear (conical) and spherical molecules, along the range of the αdistance (z-axis).

Performance of concrete reinforced with synthetic fibres obtained from recycling end-of-life sport pitches

Micro-plastics pollution has risen at an alarming pace over the last decades and it is now recognised as a leading environmental emergency. Indeed, only a very small fraction of annual plastic production is successfully reused, while the vast majority is either disposed of (mainly through incineration or landfilling) or dispersed into the environment. In this paper, polyolefins synthetic fibres, obtained from processing disposed artificial turf pitches aimed at paving sport facilities, are studied. Focus is set on assessing their potential for the Fibre Reinforced Concrete (FRC) technology. Mechanical performance is discussed at two fibre volume fractions, namely 3% and 5% vol., alongside environmental impact. The former is assessed in bending and reveals a significant enhancement of the post-crack energy dissipation capability, whose extent is compatible with what is usually obtained by the adoption of virgin fibres. This is especially significant in consideration of the light processing operated on the waste material. Indeed, life cycle assessment is adopted to evaluate the environmental impact of fibre reuse against fibre manufacturing from either virgin materials or plastic waste. It clearly appears that fibre reuse brings a double environmental benefit: on the one side, it decreases the need for new plastics and, on the other, it reduces plastic waste, whose traditional disposal technique, through incineration, entails a considerable footprint.