Sustainable Waste Management Practices Research Articles

The adsorption of chlorpyrifos and malathion under environmentally relevant conditions using biowaste carbon materials

Water bodies face persistent contamination from organophosphorus pesticides like chlorpyrifos and malathion, which pose substantial environmental and health hazards due to their toxicity and resilience in ecosystems. This study explores the potential of spent coffee grounds, a common agricultural byproduct, as an eco-friendly adsorbent for eliminating these pesticides from polluted water. Spent coffee grounds underwent carbonization at 400 °C and various activation treatments using KOH, H3PO4, CO2, and their combinations. The impact of these activation methods on the adsorption capacity of carbonized materials was assessed under environmentally relevant conditions (25 °C, pH=6, and typical pesticide concentrations in wastewater). Results revealed that the physical and chemical properties of biowaste-derived materials significantly influence their adsorption efficiency, with KOH-activated adsorbents exhibiting the highest capacities ((16.1 ± 0.8) mg g−1 for chlorpyrifos and (11.2 ± 0.2) mg g−1 for malathion). Spent coffee grounds carbonized at 400 °C without additional activation demonstrated similar adsorption performance to the best-performing material ((19.4 ± 0.4) mg g−1 for chlorpyrifos and (10.6 ± 0.4) mg g−1 for malathion), with notably lower economic and environmental costs. Given its straightforward preparation and significant adsorption capacity, this material stands out as a sustainable solution for treating agrochemical wastewater containing chlorpyrifos and malathion.

Achieving the sustainable waste management of medical plastic packaging using a life cycle assessment approach

Hospital waste management often classifies all waste, including uncontaminated plastic packaging, as hazardous, leading to incineration as the primary treatment method. While effective for safe treatment, incineration incurs high costs and significant environmental impacts. This study explores an alternative approach through the segregation and sustainable management of plastic packaging waste derived from medical device use to mitigate these environmental consequences. Using a Life Cycle Assessment, this research evaluates and compares the environmental impacts of three waste disposal scenarios of plastic packaging: hazardous waste incineration, general waste landfill, and plastic recycling. The analysis focuses on 1 kg of plastic packaging waste generated from medical devices at the Limb Vascular Center, Konkuk University Hospital, South Korea. The results show that general waste landfill has an environmental impact of 79.7 % and plastic recycling has an impact of just 11.8 %, highlighting their significantly lower environmental impacts compared to hazardous waste incineration. These findings underscore the significant benefits of adopting more sustainable waste management practices in healthcare and offering valuable insights for enhancing environmental, social, and governance (ESG) practices within hospitals.

Development of a Progressive Web Application for Optimizing Solid Waste Management in Urban Contexts: a Case Study in the Coelhos Neighborhood, Recife

Objective: Develop a Progressive Web Application (PWA) to optimize solid waste management in the Coelhos neighborhood in Recife, promoting sustainable practices. Literature Review: The study is based on emerging technologies for waste management, such as IoT and optimization algorithms, addressing challenges and benefits. Method: It includes participatory diagnosis, data collection, and development of the "Limpa+Coelhos" application, integrating technologies like Angular and Google Maps to facilitate waste collection. Results and Discussion: The application significantly increased collection efficiency and community awareness, improving interaction between users and waste management services. Research Implications: The study highlights the potential of PWAs to promote more sustainable and interactive waste management practices in urban contexts. Originality/Value: The research demonstrates the effectiveness of PWAs in improving solid waste management, contributing to the development of innovative technological solutions in urban areas.

A mini-review for identifying future directions in modelling heating values for sustainable waste management.

Global estimations suggest energy content within municipal solid waste (MSW) is underutilized, compromising efforts to reduce fossil CO2 emissions and missing the opportunities for pursuing circular economy in energy consumption. The energy content of the MSW, represented by heating values (HVs), is a major determinant for the suitability of incinerating the waste for energy and managing waste flows. Literature reveals limitations in traditional statistical HV modelling approaches, which assume a linear and additive relationship between physiochemical properties of MSW samples and their HVs, as well as overlook the impact of non-combustible substances in MSW mixtures on energy harvest. Artificial intelligence (AI)-based models show promise but pose challenges in interpretation based on established combustion theories. From the variable selection perspectives, using MSW physical composition categories as explanatory variables neglects intra-category variations in energy contents while applying environmental or socio-economic factors emerges to address waste composition changes as society develops. The article contributes by showing to professionals and modellers that leveraging AI technology and incorporating societal and environmental factors are meaningful directions for advancing HV prediction in waste management. These approaches promise more precise evaluations of incinerating waste for energy and enhancing sustainable waste management practices.

Effective methods for the decontamination of healthcare waste: Ozone and UV-C radiation process

ABSTRACT Human-generated waste, including infectious healthcare waste, poses significant risks to public health and the environment. The COVID-19 pandemic has increased the global production of infectious waste, emphasizing the need for safe and sustainable waste management practices. While autoclaves are commonly used for on-site disposal, alternative methods like ozone gas and UV-C radiation offer environmentally friendly options that effectively eliminate pathogens without leaving toxic residues. Inadequate waste management can contribute to disease transmission, while open burning releases harmful pollutants. This study investigated the effectiveness of different disinfection agents – ozone gas and UV-C radiation – on infectious solid waste contaminated with bacteria. The bacterial indicators examined were Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa. The experimental methods included operating each ozone and UV-C radiation individually and simultaneously using ozone gas and UV-C radiation. The study also investigated exposure times and various concentrations of ozone gas. The findings demonstrated that the simultaneous application of ozone gas and UV-C radiation was the most effective method for decontaminating infectious solid waste and targeting the selected bacteria. The concentration of ozone gas ranged from 165 to 5000 ppm, depending on generation time and treatment chamber volume, while exposure times varied from 1 to 180 minutes. In applying UV-C rays, complete elimination of S. aureus was observed after 60 minutes up to 6-log, while the reduction of B. subtilis and P. aeruginosa were 2-log and 3-log, respectively. Ozone gas had the ability to inactivate all strains, but when ozone gas and UV-C rays were used simultaneously, this process was accelerated and improved. The total reduction in the bacterial load was 8-log. Considering the increase in population and the subsequent increase in waste generation, adopting an environmentally friendly waste management method can be very advantageous. Implications: This study highlights the effectiveness of simultaneously applying ozone gas and UV-C radiation for decontaminating infectious solid waste, offering an environmentally friendly alternative to traditional thermal treatments like autoclave and incineration. By optimizing ozone concentrations and exposure times, this method reduces disease transmission risks and minimizes environmental impact. These findings are crucial, especially during outbreaks such as the COVID-19 pandemic, providing scalable, sustainable waste management solutions for healthcare facilities. Implementing these techniques can protect public health and the environment, setting a new standard for safe infectious waste disposal worldwide, mitigating hazardous pollutants, and reduce the exposure risk of bio-hazardous residues.

Cement modified and copper oxide enriched ferric sludge as oxygen carrier for chemical looping combustion

This study focuses on enhancing the performance of water treatment sludge as an oxygen carrier (OC) for chemical looping combustion (CLC) of municipal solid waste (MSW) syngas. High aluminate cement was introduced to augment the OC’s mechanical strength, concurrently preventing inter-particulate agglomeration, resulting in a commendable and low agglomeration rate of 3.44% after 50 cycles. The inclusion of CuO proves to be instrumental in boosting the OC’s reactivity, mitigating the loss of active components due to the addition of cement support. Notably, FSCuO10 (Ferric sludge with 10% CuO addition) demonstrates over 92% CO efficiency throughout 50 cycles, affirming the success of the dual modification of FS. The investigation also delves into comprehending the reduction process, agglomeration pathways, and the impact of varied CuO percentages has on OC performance. Extensive characterizations were conducted to elucidate OC transformations and their consequential effects on reactivity, physical characteristics, and overall performance. A noteworthy observation includes the outward migration of iron and copper during CLC, contributing to the stabilization of reactivity. In summary, the modifications implemented on FS, yield an improved OC for CLC purposes, maintaining its novelty and cost-effectiveness. The novelty stems from the interactions between CuO and FS, leading to improved reactivity and stability, as well as the extended CLC, which demonstrates the longevity of the OCs. This research contributes to the circularity of waste-derived products by effectively repurposing water treatment sludge and improving sustainable waste management practices.

Carbonization and Gasification of Cow‐Dung and Fe3O4 Nanoparticles at Different Operating Conditions for Hydrogen Production

AbstractCow dung is an abundant agricultural by‐product that poses disposal challenges. Converting this waste into a valuable energy resource aligns with sustainable waste management practices and contributes to a circular economy. This research aims at Cow dung disposal by carbonization and gasification for hydrogen generation and maximizes it by optimizing the process parameters. In the pyrolysis‐carbonization process, the influence of temperature on cow dung and its biochar characteristics was initially investigated. On the cow dung feedstock, different operating temperatures at about 400, 500, and 600 °C and response times of about 30, 60, and 120 min were tested. With CD450 as the feedstock, the gas concentrations and hydrogen yield were around 62 vol% and 0.69 m3 kg−1, respectively, for longer reaction times. Similar to this, the gas concentration and yield value for hydrogen at 600 °C gasification temperature is around 64 vol% and 0.91 m3 kg−1. Cow dung is evidently acceptable for larger hydrogen production at higher gasification temperatures and reaction times when the carbonization temperature is 450 °C. In addition, when compared to feedstock without adding nanoparticles, including Fe3O4 nanoparticles may increase the hydrogen concentration and yield by around 13.5 % and 4.21 %, respectively.

Speculative investigation of performance & combustion of waste plastic oil blended with diesel as an alternate fuel in single cylinder diesel engine employing is: 10000 standards

In contemporary times, plastic waste recycling has emerged as a crucial trend, presenting significant potential for plastic reformulation and recyclability. Waste plastic, owing to its high calorific value and abundance, serves as a promising energy source. Through the pyrolysis process, plastic waste can be converted into pyrolysis oil, which exhibits properties akin to conventional diesel fuel and can be seamlessly integrated into engines. This study investigates the synthesis of waste plastic oil (WPO) via pyrolysis using a diverse feedstock comprising various types and grades of plastic. The resulting oil, resembling diesel in characteristics, is evaluated for its performance in a compression ignition (CI) engine equipped with a variable compression ratio.Experimental tests are conducted using blends of WPO and diesel ranging from 0% to 100%, across different engine loads spanning from partial to full load conditions (2 kg to 12 kg). The combustion characteristics, engine performance metrics, and emission profiles are meticulously analyzed and compared against those of conventional diesel fuel. The findings indicate that the engine exhibits comparable performance with WPO at higher loads, akin to that with diesel. However, at lower loads, an extended delay period is observed, contributing to engine stabilization.These results underscore the potential of renewable plastic oil as a viable alternative fuel for diesel engine applications, particularly under specific operating conditions. The study provides valuable insights into the feasibility and performance implications of integrating waste plastic oil into compression ignition engines, contributing to the ongoing discourse on sustainable energy solutions and waste management practices.

Solid waste management awareness and practices in coastal communities

Effective solid waste management (SWM) is paramount for environmental sustainability and public health, particularly in coastal communities. This cross-sectional descriptive study determines SWM awareness and practices among 399 households in selected coastal barangays in the City of Mati, Davao Oriental, Philippines. Employing a structured four-point Likert-type survey through KoboCollect applications, this study evaluates SWM awareness and practices while examining the impact of socio-demographic factors on these aspects. The results reveal moderate SWM awareness (X̄=2.55) and practices (X̄=2.66) in these coastal communities, indicating a baseline level of environmental consciousness and waste management efforts. However, there was lack of familiarity with legal and regulatory frameworks (X̄=1.97), including the Republic Act 9003 and local ordinances related to SWM. Notable gaps are also identified in SWM practices, mainly in waste segregation (X̄ = 2.55) and avoidance to waste-burning (X̄=2.56). Socio-demographic factors, such as age, educational attainment, household size, and family income, significantly influence SWM awareness and practices. These findings underscore the need for targeted educational campaigns and community engagement strategies to enhance awareness of SWM regulations. Addressing these gaps is necessary for developing effective interventions to promote sustainable waste management practices in these coastal areas, thus protecting marine ecosystems and supporting the well-being of local communities.

A comprehensive review of landfill leachate treatment technologies

The management of landfill leachate presents a significant environmental challenge, necessitating a comprehensive and dynamic treatment approach. This comprehensive review delves into the critical issue of landfill leachate treatment, exploring its environmental impact, treatment technologies, regulatory frameworks, and the path towards sustainable management practices. This review explores the complexities of landfill leachate, emphasizing the need for sustainable waste management practices to safeguard environmental health. Our analysis highlights the evolution of conventional and advanced treatment technologies designed to mitigate these risks, focusing on membrane technologies, advanced oxidation processes, and the promising potential of emerging techniques such as adsorption and biological nutrient removal. These technologies are evaluated for their efficiency, cost implications, and sustainability impacts, underscoring the challenges and opportunities within the current landscape of leachate treatment. The review aims to provide insights into designing efficient and effective treatment systems through a detailed analysis of conventional and advanced treatment methods. By examining a case study in Changsha City, the effectiveness of a comprehensive treatment system integrating various technologies is demonstrated. The review underscores the interconnectedness of human activities, environmental health, and waste management, emphasizing the importance of a holistic approach. It stresses the continuous improvement of leachate treatment technologies and the adoption of sustainable practices to reduce the environmental footprint of landfills. Ultimately, it calls for integrating multiple treatment processes, economic considerations, and readiness to address future challenges in landfill leachate treatment, contributing to the advancement of sustainable waste management practices.

Optimizing Plastic Waste Reduction through Education and Ecobrick Implementation in Penjalin Village

This study investigates the implementation of ecobricks as a strategy to reduce plastic waste in Penjalin Village. The research focused on the effectiveness of educational workshops and community involvement in promoting sustainable waste management practices. Data was collected through surveys, interviews, workshops, and observations conducted over three months. The results showed that plastic waste is a significant issue in the village, with limited awareness of proper waste disposal methods. The introduction of ecobricks, coupled with community education, resulted in increased participation and a positive shift in attitudes towards environmental sustainability. The study also found that the success of the ecobrick initiative relies heavily on continued education and community engagement. The findings suggest that similar strategies could be effective in other rural areas facing similar challenges. This research contributes to the broader discourse on sustainable waste management and highlights the potential of ecobricks as a practical solution to plastic waste problems.

Life Cycle Assessment as a Catalyst for Embedding Sustainability in Waste Management Practices

The establishment of sustainable campuses acts as a catalyst, fostering a Living Lab environment where active community engagement is crucial. Recognizing the pivotal role of waste management, university campuses prioritize detailed mapping and characterization of organic waste streams. This process paves the way for the identification of alternative scenarios that reduce and divert waste from landfills through valorization routes such as composting and anaerobic digestion. Acknowledging students' pivotal role in shaping sustainable solutions, their perceptions of solid waste separation assume significance. The effectiveness of the current separation system is critical, especially given the monitoring of bin contamination levels, revealing hindrances to organic waste valorization. Life Cycle Assessment (LCA) emerges as a valuable tool for identifying alternative scenarios for waste reduction and diversion, encompassing anaerobic digestion, composting, and waste-to-food strategies. This study centers on evaluating and reshaping student perspectives on organic waste separation and end-of-life waste management through LCA. A comprehensive survey was designed to elucidate current perspectives on the efficiency and communication of the existing waste management system. Student insights into waste separation practices revealed that the major barriers to effective waste management practices on campus include a lack of education and awareness regarding waste separation. The survey findings also underscore the significance of LCA not only in measuring carbon footprints but also in influencing perceptions and behaviors towards sustainable waste management practices. In conclusion, our study contributes to the discourse on embedding sustainability in educational settings, offering valuable insights for institutions aspiring to drive positive change through innovative waste management strategies.

Waste Management In India With Special Reference To Ahmedabad City

This comprehensive study examines the complex landscape of waste management in India, with a particular focus on Ahmedabad city in Gujarat. The research delves into the current state of waste management practices, the socio-economic conditions of rag pickers, and the emerging trends in eco-friendly packaging. Through extensive literature review, field surveys, and data analysis, this paper provides insights into the challenges and opportunities in India's waste management sector. The study reveals significant gaps in waste collection and processing systems, the precarious living conditions of rag pickers, and the potential for eco-friendly packaging to mitigate waste generation. The findings underscore the need for integrated waste management approaches, improved working conditions for informal waste workers, and widespread adoption of sustainable packaging solutions. This research contributes to the growing body of knowledge on urban waste management in developing countries and offers policy recommendations for more sustainable and equitable waste management practices.

Assessing Health and Environmental Risks: Educational Awareness on Plastic Usage and Solid Waste Disposal in Bahawalpur

The review paper explores the increasing challenges posed by plastic pollution and improper solid waste management in Bahawalpur. The population has continued to increase, and there is ever-increasing urbanization; this has contributed to the increase in plastic and solid waste production, such as the single use of plastic bags and bottles. These waste materials contribute to environmental degradation, affecting soil quality and contaminating water systems. Improper disposal contributes to public health challenges like respiratory and waterborne diseases and vector-borne ailments like malaria and dengue fever. A fully equipped waste management framework is needed to solve more problems in Bahawalpur; this leads to a filled drainage system, urban flooding, and the discharge of hazardous wastes. The review also explains the level of community health education used to ensure sustainable waste management practices are practiced. Hence, the paper encourages the involvement and expansion of community-based programs and public or private-founded collaboration to support and practice recycling and the appropriate management and minimization of single-use plastics. Smart solutions are also briefly touched upon as potential solutions, including implementing waste-to-energy plants and smart bins. Consequently, this review calls for enhanced stewardship, more specific to public sensitization against further pollution of Bahawalpur and other similar urban settings by plastic and solid waste.

Evaluation of waste composition for biochar production as a sustainable waste management approach

Background: To meet human life needs, fuel energy is obtained from fossil sources, such as coal, found in the Earth's crust. However, non-renewable energy sources in the Earth's crust will eventually run out. One alternative fuel is the production of biobriquettes from various types of waste. Methods: Using a literature review method, this study aims to determine which waste is most suitable for use in the production of biobriquettes. The samples taken are journals sourced from Google Scholar ranging from 2017 to 2022 that align with the discussion topic. Findings: Among various raw materials, the best waste for biobriquette production is found to be a mixture of dacron waste and corn cob, with a moisture content of 3.45% and a carbon value of 7986.45 cal/g. Conclusion: The results of the above study indicate that the production of biobriquettes from dakron waste and corn cobs is the best option because it yields the highest calorific value and the lowest moisture content, in accordance with SNI 01/6235/2000. Novelty/Originality of this article: This study presents a novel approach by identifying a specific combination of dacron waste and corn cob for biobriquette production, showcasing its superior calorific value and low moisture content, thus contributing to sustainable energy solutions and waste management practices.

Comprehensive life cycle assessment of garden organic waste valorisation: A case study in regional Australia

This study evaluates the environmental impacts associated with the conversion of garden organic waste into value-added products, namely compost or biochar, employing various processes. Three distinct scenarios are considered: composting garden organic waste followed by screening of oversized materials (CBP), pyrolysis of oversized screenings of compost into biochar AP(I), and in-situ conversion of garden organics into biochar AP(II). A comprehensive Life Cycle Assessment (LCA) was conducted using OpenLCA software and life cycle impact assessment was conducted using Recipe 2016 midpoint methodology. The environmental ramifications of each scenario were assessed, optimising transport distances in AP(II) to achieve a functional unit of one tonne of biochar produced within a cradle-to-gate system boundary. For the first time, this study offers a holistic exploration of the benefits of soil biochar application, extending its scope to climate change mitigation, incorporating the optimisation of transport distance and its influence when scaling up the technology. The results revealed that global warming was increased from 125 kgCO2 eq during composting of garden waste to 232 kgCO2 eq where oversized screenings of compost is converted to biochar at an off-site facility. However, direct conversion of the oversized organic waste to biochar, without composting, showed reduced global warming impact of 56 kgCO2 eq, and is thus the most favourable scenario to limit climate impacts of this fraction of organic garden waste. However, among 18 environmental impact indicators studied, eight indicators were either not influenced or did not significantly increase by transport distance to an off-site pyrolysis facility, while the magnitude of 10 impact indicators increased with transport distance. The insights and methodologies presented in this study hold global relevance, based on an actual case study in regional Australia, offering valuable recommendations for sustainable waste management practices and establishing biochar as a carbon-neutral or carbon-negative solution. The findings contribute to existing waste management knowledge and provide guidance for accessible carbon dioxide removal and soil carbon sequestration technologies.

Analysis of the Impact of Biomass/Water Ratio, Particle Size, Stirring, and Catalysts on the Production of Chemical Platforms and Biochar in the Hydrothermal Valorization of Coffee Cherry Waste

In Colombia alone, 12.6 million bags of green coffee are produced, but at the same time, 784,000 tons of waste biomass are dumped in open fields, of which only 5% is recovered or used, and 10 million tonnes of coffee emit 28.6 million tonnes of CO2 eq annually. This presents a worrying dilemma, and the need to develop a technology to transform the waste into usable products is increasing. As a response to this, the valorization of coffee waste was explored through the production of biochar and platform chemicals by implementing a set of hydrothermal experiments with different biomass/water ratios (1:5, 1:10, 1:20, 1:40), particle sizes (0.5, 1, 2, 5 mm), stirring rates (5000 and 8000 rpm), and catalysts (H2SO4, NaHCO3 and CH3COOH) at 180, 220, and 260 °C in a batch reactor with autogenous pressure. Notably, the smaller B:W ratios of 1:20 and 1:40, as well as smaller particle sizes of 0.5 and 1 mm, yielded higher amounts of platform chemicals, while stirring showed minimal influence. CH3COOH significantly enhanced the process compared to other catalysts. The biochar was characterized as anthracite, and this obtaining of coal-like materials from biomass itself represents a remarkable feat. Said anthracite presented little to no variation in physical parameters, while catalysts induced functionalization. By optimizing factors like B:W ratio, particle size, and catalyst application, valuable insights have been gained into enhancing the yield of platform chemicals and quality of biochar from coffee waste. The findings not only contribute to sustainable waste management practices but also highlight the importance of exploring innovative solutions for utilizing agricultural by-products effectively.

Revitalizing municipal solid waste recycling: Review of current U.S. policies and potential directions for the circular economy

Municipal Solid Waste (MSW) recycling is a pivotal pillar in waste reduction and sustainable resource management. However, the United States (U.S.) is behind its schedule for the national recycling rate goal of 50% by 2030, which California is almost achieving. To this end, we review and compare the national and California recycling policies. Our analysis reveals that while there have been some positive changes toward sustainable waste management practices, significant gaps remain, particularly in the lack of a comprehensive national recycling law. The current federal allocation of funds has also been inadequate for achieving the national goal. Therefore, we identify policy options to grow toward a national policy and funding for recycling infrastructure and education. Using California as a model, we provide federal law options to balance recyclable supply and demand. These options are paired with future U.S. MSW policy and research directions.

Transformasi Limbah Menjadi Hijau: Revitalisasi Taman Desa Sukaresmi Melalui Pengelolaan Limbah

Desa Sukaresmi, located in the Cikarang Selatan sub-district of Bekasi Regency, West Java, has experienced rapid population growth in tandem with industrial development in its vicinity Although this increase has brought positive economic impacts, environmental issues, particularly waste management, pose significant challenges The lack of innovation in managing organic and non-organic waste has led to environmental pollution and the loss of green spaces The Real Work Lecture Program (KKN) in Desa Sukaresmi proposes a solution by transforming waste into green elements through the revitalization of the village park Organic waste will be processed into compost to enrich the soil, while non-organic waste will be recycled into park decorations. This program aims to enhance collective awareness among residents about the importance of waste management and environmental preservation, making Desa Sukaresmi a pioneer in sustainable waste management practices that can be emulated by other villages The method used in this service is direct observation in Desa Sukaresmi The results obtained from this service include the revitalization of a beautiful village park in front of the Desa Sukaresmi office, with a satisfaction rating of 90% from the community of Desa Sukaresmi.

Sustainable Waste Management in Japan: Challenges, Achievements, and Future Prospects: A Review

Japan is subject to global interest due to its waste management system, which aims for sustainability and is known for its efficiency. The purpose of this study is to examine Japan’s steps towards sustainable waste management practices and highlight its formation, achievements, problems, and prospects for the future. Through a comprehensive review of official governmental data and the academic literature, the main achievements—including extensive government initiatives such as proposing programs, plans, and legislation for sustainable waste management and encouraging public involvement in establishing a Sound Material-Cycle Society (SMCS) and 3Rs—were defined. Thus, the state and the population alike take general measures to combat pollution. Looking at the future of waste management in Japan, the country continues to struggle despite all these efforts and impressive results. It is focusing on developing more sustainable and cost-effective solutions. This includes investing in new technologies, increasing efforts to reduce and recycle waste, and promoting environmental awareness.