| 1. |
- Oruganti, Raj Kumar, et al.
(author)
-
A comprehensive review on the use of algal-bacterial systems for wastewater treatment with emphasis on nutrient and micropollutant removal
- 2022
-
In: Bioengineered. - : Taylor & Francis. - 2165-5979 .- 2165-5987. ; 13:4, s. 10412-10453
-
Journal article (peer-reviewed)abstract
- The scarcity of water resources and environmental pollution have highlighted the need for sustainable wastewater treatment. Existing conventional treatment systems are energy-intensive and not always able to meet stringent disposal standards. Recently, algal-bacterial systems have emerged as environmentally friendly sustainable processes for wastewater treatment and resource recovery. The algal-bacterial systems work on the principle of the symbiotic relationship between algae and bacteria. This paper comprehensively discusses the most recent studies on algal-bacterial systems for wastewater treatment, factors affecting the treatment, and aspects of resource recovery from the biomass. The algal-bacterial interaction includes cell-to-cell communication, substrate exchange, and horizontal gene transfer. The quorum sensing (QS) molecules and their effects on algal?bacterial interactions are briefly discussed. The effect of the factors such as pH, temperature, C/N/P ratio, light intensity, and external aeration on the algal-bacterial systems have been discussed. An overview of the modeling aspects of algal-bacterial systems has been provided. The algal-bacterial systems have the potential for removing micropollutants because of the diverse possible interactions between algae-bacteria. The removal mechanisms of micropollutants ? sorption, biodegradation, and photodegradation, have been reviewed. The harvesting methods and resource recovery aspects have been presented. The major challenges associated with algal-bacterial systems for real scale implementation and future perspectives have been discussed. Integrating wastewater treatment with the algal biorefinery concept reduces the overall waste component in a wastewater treatment system by converting the biomass into a useful product, resulting in a sustainable system that contributes to the circular bioeconomy.
|
|
| 2. |
- Bathi, Jejal Reddy, et al.
(author)
-
Behavior of engineered nanoparticles in aquatic environmental samples : Current status and challenges
- 2021
-
In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 793
-
Research review (peer-reviewed)abstract
- The increasing use of engineered nanoparticles (ENPs) in consumer products has led to their increased presence in natural water systems. Here, we present a critical overview of the studies that analyzed the fate and transport behavior of ENPs using real environmental samples. We focused on cerium dioxide, titanium dioxide, silver, carbon nanotubes, and zinc oxide, the widely used ENPs in consumer products. Under field scale settings, the transformation rates of ENPs and subsequently their physicochemical properties (e.g., toxicity and bioavailability) are primarily influenced by the modes of interactions among ENPs and natural organic matter. Other typical parameters include factors related to water chemistry, hydrodynamics, and surface and electronic properties of ENPs. Overall, future nanomanufacturing processes should fully consider the health, safety, and environmental impacts without compromising the functionality of consumer products.
|
|
| 3. |
- Bheemasetti, Sravani, et al.
(author)
-
Upcycling the solid wastes as precursors for graphene production
- 2023
-
In: Graphene Extraction from Waste. - : Elsevier. - 9780323909143 - 9780323909150 ; , s. 1-21
-
Book chapter (peer-reviewed)abstract
- Owing to limited markets for recycled products, the United States annually discards~294 million tons of municipal solid waste (MSW) into landfills. These recycling rates for plastics and food wastes are as low as 7% and 3%, respectively. There is a need for stimulating innovative strategies for upcycling MSWs. This chapter discusses viable strategies for upcycling MSWs as precursors for graphene production using well-established nano-manufacturing techniques. We discuss the use of readily available MSW components as raw materials and the waste-to-energy infrastructure as a source of waste heat.
|
|
| 4. |
- Carvalho, Ricardo L., et al.
(author)
-
Bioenergy strategies to address deforestation and household air pollution in western Kenya
- 2019
-
In: European Biomass Conference and Exhibition Proceedings. - : ETA-Florence Renewable Energies. ; , s. 1536-1542
-
Conference paper (peer-reviewed)abstract
- Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden disease due to household air pollution. The Long-Range Energy Alternatives Planning (LEAP) system and the Life-Cycle Assessment tool Simapro 8.5 were applied for analyzing biomass strategies for the region. The calculation of the residential energy consumption and emissions was based on scientific reviews and original data from experimental studies. The research shows the effect of four biomass strategies on the reduction of wood fuel use and short-lived climate pollutant emissions. A Business As Usual scenario (BAU) considered the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) considered the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluated a mix of the ICS, PGS and BGS. The study shows that, energy use will increase by 8% (BGS), 20% (INT), 26% (PGS), 42% (ICS) and 56% (BAU). The BGS has the lowest impact on global warming, particle formation, terrestrial acidification, fossil resource scarcity, water consumption, as well as on eutrophication followed by the PGS and INT.
|
|
| 5. |
- Carvalho, Ricardo Luís, et al.
(author)
-
Environmental Sustainability of Bioenergy Strategies in Western Kenya to Address Household Air Pollution
- 2020
-
In: Energies. - : MDPI. - 1996-1073. ; 13:3
-
Journal article (peer-reviewed)abstract
- Over 640 million people in Africa are expected to rely on solid-fuels for cooking by 2040. In Western Kenya, cooking inefficiently persists as a major cause of burden of disease due to household air pollution. Efficient biomass cooking is a local-based renewable energy solution to address this issue. The Life-Cycle Assessment tool Simapro 8.5 is applied for analyzing the environmental impact of four biomass cooking strategies for the Kisumu County, with analysis based on a previous energy modelling study, and literature and background data from the Ecoinvent and Agrifootprint databases applied to the region. A Business-As-Usual scenario (BAU) considers the trends in energy use until 2035. Transition scenarios to Improved Cookstoves (ICS), Pellet-fired Gasifier Stoves (PGS) and Biogas Stoves (BGS) consider the transition to wood-logs, biomass pellets and biogas, respectively. An Integrated (INT) scenario evaluates a mix of the ICS, PGS and BGS. In the BGS, the available biomass waste is sufficient to be upcycled and fulfill cooking demands by 2035. This scenario has the lowest impact on all impact categories analyzed followed by the PGS and INT. Further work should address a detailed socio-economic analysis of the analyzed scenarios.
|
|
| 6. |
- Chilkoor, Govinda, et al.
(author)
-
Sustainability of renewable fuel infrastructure : a screening LCA case study of anticorrosive graphene oxide epoxy liners in steel tanks for the storage of biodiesel and its blends
- 2017
-
In: Environmental Science. - : Royal Society of Chemistry. - 2050-7887 .- 2050-7895. ; 19:2, s. 141-153
-
Journal article (peer-reviewed)abstract
- Biodiesel is a widely used fuel that meets the renewable fuel standards developed under Energy Policy Act of 2005. However, biodiesel is known to pose a series of abiotic and biotic corrosion risks to storage tanks. A typical practice (incumbent system) used to protect the tanks from the risks include: (i) coat the interior surface of the tank with solvent free epoxy (SFE) liner, and (ii) add a biocide in the tank. We present a screening-level, life cycle assessment study to evaluate and compare the environmental performance of graphene-oxide (GO)-epoxy (GOE) liner with the incumbent system. TRACI is used as an impact assessment tool to model midpoint environmental impacts for the ten categories: global warming potential (GWP, kg CO2 eq.); acidification potential (AP, kg SO2 eq.); potential human health damage impacts due to carcinogens (HH-CP, CTUh) and non-carcinogens (HH-NCP, CTUh); potential respiratory effects (REP, kg PM2.5 eq); eutrophication potential (EP, kg N eq); ozone depletion potential (ODP kg CFC-11 eq); ecotoxicity potential (ETXP, CTUe); smog formation potential (SFP kg O3 eq); and fossil fuel depletion potential (FFDP MJ surplus). The equivalent functional unit of the LCA study is designed to protect the 30 m2 of the interior surface (unalloyed steel sheet) of a 10,000 liters biodiesel tank against abiotic and biotic corrosion during its service life of 20 years. Overall, this LCA study highlights an improved environmental performance for the GOE liner compared to the incumbent system; GOE-liner system showed: 91% lower ODP impacts; 59% smaller for REP; 62% smaller for AP; 67-69% smaller for GWP and HH-CP; 72-76% smaller for EP, SFP, and FFDP; and 81-83% smaller for ETXP and HH-NCP categories. The scenario analysis study reveals that these potential impacts change by less than 15% when the GOE liners are functionalized with silanized-GO nanosheets or GO-reinforced, polyvinyl carbazole to improve the antimicrobial properties. The results from uncertainty analysis indicate that the impacts for the incumbent system are more sensitive to changes in key modeling parameters compared to that for GOE liner system.
|
|
| 7. |
- Shanmugam, Kavitha, 1992-, et al.
(author)
-
A sustainable performance assessment framework for circular management of municipal wastewater treatment plants
- 2022
-
In: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 339
-
Journal article (peer-reviewed)abstract
- Municipal wastewater treatment plants (WWTPs) could become valuable contributors to a circular economy by implementing the 3R principles (reduce, reuse, and recycle). While reducing the pollution load of sewage is the primary objective of a WWTP, this process generates several potentially valuable byproducts including treated effluent, biogas, and sludge. The effluent can be reused in various end use applications and biogas can be reused as a fuel (for electricity generation, transportation, and cooking) or a chemical feedstock. The sludge can either be directly recycled as soil conditioner or via thermochemical/biochemical processing routes to recover material (e.g., hydrochar), energy (e.g., heat, and syngas), and resource value (phosphorus). This work presents a five-layered assessment framework for quantitatively evaluating the sustainable value of municipal WWTPs by using life cycle assessment (LCA) and life cycle costing assessment (LCCA) tools. In addition, indicators reflecting potential benefits to stakeholders and society arising from investments into municipal WWTPs such as the private return on investment (PROI) and the environmental externality costs to investment ratio (EECIR). The framework is validated in a hypothetical case study where the sustainable value of a circularly managed municipal WWTP is evaluated in situations involving multiple byproduct utilization pathways. Four future circular options (FCOs) are examined for a 50,000 m3/d capacity WWTP treating sewage up to tertiary standards. The FCOs mainly differ in terms of how biogas is reused (to meet the WWTP's internal energy demands, as cooking fuel, or as fuel for city buses after upgrading) and how sludge is recycled (as soil conditioner or by producing hydrochar pellets for electricity generation). The FCO in which treated effluent is reused in industry, biogas is used as cooking fuel, and sludge is used as a soil conditioner provides the greatest sustainable value (i.e., the lowest private costs and environmental externality costs (EEC) together with high revenues), the highest PROI, and the lowest EECIR. The strengths and limitations of the proposed assessment framework are also discussed. © 2022 The Authors
|
|
| 8. |
- Shanmugam, Kavitha, 1992-
(author)
-
Circularity Assessment of Water and Waste in Cities : A Proposed Framework for Sustainable Performance Evaluation using LCA and LCC
- 2021
-
Doctoral thesis (other academic/artistic)abstract
- Urbanization is a global phenomenon, happening on a massive scale and at a rapid rate, with 68% of the planet’s population predicted to be living in cities by 2050 (UN-DESA, 2018). The sustainability of a city (Goal 11 of UN SDGs) undergoing rapid urbanization depends on its ability to maintain a low consumption of resources and materials at any given time (referred to as the urban metabolic rate), whilst simultaneously providing essential municipal services to its inhabitants, such as a water supply, wastewater treatment and solid waste management. The latter must comply with circular economy principles, meaning recovery of byproducts, prevention of discharge of toxic pollutants, and avoidance of landfill usage. The appended papers in the thesis (Papers I–V) describe sustainable assessments of wastewater and waste services to increase their degree of circularity, using tools such as Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). Paper I describes the environmental performance of using the biogas from a Wastewater Treatment Plant (WWTP) and converting it to Liquefied Biomethane (LBM), which can used as fuel in Tractor-Trailers (TT). Overall, the study suggests that changing from diesel to LBM fuel improves the environmental performance of TT. However, the magnitude of environmental benefit depends on an alternate source of electricity required for operation of the WWTP. Paper II evaluates the Social Cost-Benefit Analysis (SCBA) of Compressed Biomethane (CBM) obtained from a food waste digestion plant in Mumbai, India for use as a fuel in transit buses. SCBA results indicate that the food waste-based CBM model can save 6.86 billion Indian rupees (99.4 million USD) annually for Mumbai. Paper III describes the Sustainable Return on Investment (SROI) of lightweight Advanced High Strength Steel (AHSS) and Carbon Fiber Reinforced Polymer (CFRP) intensive multi-material Body in White (BIW) for automobiles. The SROI of CFRP BIWs is maximized when carbon fiber production uses energy from a low carbon-intensity electric grid or decentralized sources such as waste-to-energy incineration plants. Paper IV assesses the ecoefficiency of a thermal insulation panel that consists of a Polyurethane (PU) foam core sandwiched between two epoxy composite skins, prepared by reinforcing Glass Fibers (GF) and SFA (Silanized Fly Ash) in epoxy resin. The results revealed that the ecoefficiency of the composite panels is positive (47%) and superior to that of market incumbent alternatives with PU foam or rockwool cores and steel skins. Paper V quantifies the Total Cost to Society (TCS) (sum of private cost and environmental externalities cost) of a centralized urban WWTP, including the operation as well as byproduct utilization stream. The environmental performance and circular compliance are both factored in, when determining the TCS of a WWTP. The results revealed savings of 1.064 million USD, which include direct and indirect revenues to the plant, as well as avoidance costs attributed to environmental externalities. Based on the studies described in4these papers, a five-stage assessment framework for determining the overall sustainability performance of essential treatment services in a city is proposed in this thesis. The framework considers the combined effect of urban metabolic features and initiatives aimed at improving circular compliance of essential services.
|
|
| 9. |
- Upadhyayula, Venkata Krishna Kumar, et al.
(author)
-
Wind Turbine Blades Using Recycled Carbon Fibers : An Environmental Assessment
- 2022
-
In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:2, s. 1267-1277
-
Journal article (peer-reviewed)abstract
- Polymers reinforced with virgin carbon fibers (VCF) are being used to make spar caps of wind turbine (WT) blades and polymers with glass fibers (GF) to make skins of the blade components. Here, we assess the life cycle environmental performance of the hybrid blades with spar caps based on VCF and the shells and shear webs based on RCF (recycled CF) composites (RCF-hybrid). The production of the WT blades and associated reinforced polymers is assumed to occur in Sweden, with their uses and end-of-life management in the European region. The functional unit is equivalent to three blades in an offshore WT with the market incumbent blades solely based on the GF composite or the hybrid option. The RCF-hybrid blades offer 12-89% better environmental performance in nine out of 10 impact categories and 6-26% better in six out of 10 impact categories. The RCF-hybrid blades exhibit optimum environmental performance when the VCF manufacturing facilities are equipped with pollution abatement systems including regenerative thermal oxidizers to reduce ammonia and hydrogen cyanide emissions; spar caps are made using VCF epoxy composites through pultrusion and resin infusion molding, and the blade scrap is mechanically recycled at the end of life. The energy and carbon payback times for the RCF-hybrid blades were found to be 5-13% lower than those of the market incumbents.
|
|
| 10. |
- Yacout, Dalia, et al.
(author)
-
An evaluation of different climate matrices used in biomass energy research
- 2020
-
In: Current developments in biotechnology and bioengineering. - Amsterdam : Elsevier. - 9780444643094 - 9780444643100 ; , s. 179-204
-
Book chapter (peer-reviewed)abstract
- Renewable energy production from biomass sources and related bio-based economy is gaining more and more attention nowadays. Research related to biomass and bio-based fuels is an important part of the strategic agenda of many countries in Europe and Asia. Furthermore, upscaling investigation in the area is undergoing in many other countries around the globe like United States, China, and India. The expansion of the biofuels usage raises concerns related to their production sustainability, including several environmental, economic, and social aspects. The aim of this chapter is to present in detail the evaluation of different climate matrices used in global biomass energy research. A strategic framework for production of biofuels and their utilization is also presented. This strategic framework merges the different environmental indicators and conversion technologies in order to achieve a sustainable circular bio-based economy.
|
|
