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In present investigation, aluminum hydroxide-sweet lime biosorbent (AlOH-SL) was applied for defluoridation of groundwater. AlOH-SL biosorbent (1:3) was chemically characterized with the help of SEM-EDX, XRD, and FTIR. The defluoridation process was optimized against biosorbent dose, fluoride concentration, reaction time, and pH of the medium. Findings depicted that AlOH-SL has excellent fluoride removal potential (94.5% at 2ppm and 74% at 10ppm) at pH 6 with adsorbent dose of 5 mg/l. Time to saturation was found to be 30 min. Monolayer chemisorption of fluoride was confirmed by Langmuir isotherm (R2 =0.975) with pseudo-second order kinetics (R2 =0.985). Results gives direction towards utilizing wet waste can be energy efficient process for fluoride removal. The process shall be helpful in minimizing carbon footprint and supports the sustainable model of water decontamination. Further, utilization of discarded fruit peels provides opportunity to generates wealth from waste and moderation of waste management. [ABSTRACT FROM AUTHOR]

The proper disposal of home garbage has recently emerged as a pressing issue on a global scale. Also, the city government has been trying to get people to separate their dry and moist trash. But there is still a problem with trash management and a big domestic population that isn’t helping out. This paper details the process of creating a waste management system that separates organic kitchen trash into dry and moist categories. Both models are part of the proposed system: The first step is to design a bin that can separate dry and moist trash. Additionally, a composting facility is showcased for the purpose of transforming organic waste into compost. Twenty homes’ worth of garbage was fed into the suggested model, and the results show promise for trash segregation and composting.

This paper explores greenhouse gas emission intensity and economy of centralized and on-site wet waste disposal mode, while comprehensively evaluating the two modes for decision-making. Based on the fieldwork in Shanghai's 20 campuses of 15 universities, multiple scenarios that can reflect the different levels of technology and management in reality, were set for the following studies. The greenhouse gas emissions generated from centralized and on-site disposal modes of wet waste were calculated in two emission scenarios using Life Cycle Assessment, Life Cycle Inventory, and the IPCC 2006 method. Additionally, the continuous cost input from the universities for the two disposal modes was analyzed in three cost-input scenarios using the Net Present Value method. Furthermore, a comprehensive evaluation of the two modes was also conducted by using Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation under the five main factors of greenhouse gas emission—control, economy, stability, education and innovation, and bargaining power for municipal sanitation departments. The results revealed that the centralized disposal mode is superior to the on-site disposal mode in terms of greenhouse gas emission control and economy. The centralized disposal mode is a more rational choice due to the better comprehensive evaluation performance. It was also emphasized that the construction of the wet waste disposal system is so complicated that the academic community and the policymakers may have to pay more attention to the integration of system design, industrial development, and other aspects of wet waste disposal. [ABSTRACT FROM AUTHOR]

Valorizing wet wastes to sustainable aviation fuel (SAF) can be achieved through sequential arrested anaerobic digestion (AAD) to volatile fatty acids (VFAs) and thermochemical catalytic upgrading. Alternatively, conventional anaerobic digestion (AD) can use wet waste to produce biogas (for electricity generation), biomethane, or green hydrogen. To assess the VFA-SAF pathway, we conducted a comprehensive techno-economic analysis (TEA) of each approach using Aspen Plus and discounted cash flow models, coupled with life cycle assessment (LCA) to estimate fuel carbon intensity (CI) and evaluate the implications of policy incentives for carbon emissions reduction. First, we calculated the minimum fuel selling price (MFSP) required to meet a 10 % internal rate of return (IRR) for each product without policy incentives. In this scenario, all pathways faced challenges in meeting the market values of equivalent fossil-based products. Next, we examined projected costs for alternative sustainable technologies and found that SAF and biomethane from wet waste were competitive, while electricity and hydrogen costs were significantly higher. Finally, we incorporated current policy incentives; with incentives, all pathways exceeded a 10 % IRR using fossil-equivalent selling prices. Among all the options considered, VFA-SAF produced the most profitable carbon-negative fuel that was economically competitive with alternative sustainable technologies. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigated the co-pyrolysis characteristics and kinetics of sewage sludge (SS) and wet waste (WW) using thermogravimetric-Fourier transform infrared spectrometry-gas chromatography/mass spectrometry (TG-FTIR-GC/MS) and artificial neural network (ANN). The proportion of WW is 0, 10, 30, 50, 70, and 100%, respectively. These mixtures were heated from 30 to 900 °C at three heating rates (10, 20, and 40 °C/min). The change of gas functional groups with different blends (-OH, –CH, CO 2 , C C, phenol, CO, and NH 3) was detected by FTIR. S3W7 has a synergistic effect on the pyrolysis in all temperature ranges and can also greatly suppress CO 2 emission (−35.25%), which is of practical significance to carbon neutrality. S3W7 was recommended as the best ratio. The gas products of S3W7 were obtained by GC/MS, which were mainly nitrides (C 5 H 5 N, C 4 H 11 N, etc.), hydrocarbons containing C O (C 3 H 6 O2, C 7 H 8 O 2 , etc.), and furans (C 5 H 6 O 2 , C 6 H 8 O, etc.). The apparent activation energy (E) was measured using Flynne-Walle-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods. Machine learning methods were used to analyze the pyrolysis. ANN19 was found the best prediction model of 21 models. The equation to predict TG data was established. [Display omitted] [ABSTRACT FROM AUTHOR]

Landfills have been considered the most convenient approach for dealing with waste from time immemorial, even though some have led to disasters of catastrophic proportions. Moreover, recent findings by the International Panel on Climate Change (IPCC) suggest that the decomposing fraction of landfill waste that generates greenhouse gases (GHGs) may not be adequately accounted for and could become a critical issue in our effort to restrict atmospheric temperature increases to 1.5 °C above pre-industrial levels. (According to the IPCC, the maximum atmospheric temperature rise is a factor of cumulative net CO2 emissions as well as net non-CO2 radiative forcing. These anthropogenic forcing agents include methane, nitrous oxide and other trace gases from landfill sites. In that sense, landfills can tip the balance from 1.5 towards 2 degrees of warming). This paper draws on data from a number of countries for review and is a timely reminder that society needs to develop a more environmentally and socially sensitive set of methods that could ultimately replace landfills. The paper first examines problems connected with landfills and evaluates alternatives such as incineration, biomass burning and mechanical biological treatment, which generally present their own problems. The paper then considers the range of materials conventionally dispatched to landfill, dealing with them in the context of a zero-waste philosophy. The conclusions propose more disciplined waste management to embrace collective accountability, wherein those who create the waste—chiefly, households and businesses—would be expected to deal with it responsibly. With attitudinal changes and education, supported by regulatory measures, it should be possible to reach the long-term objective of zero waste and the retirement of the traditional landfill.

As the demand for utilizing environment-friendly and sustainable energy sources is increasing, the adoption of waste-to-energy technologies has started gaining attention. Producing biogas via anaerobic digestion (AD) is promising and well-established; however, this process in many circumstances is unable to be cost competitive with natural gas. In this research, we provide a technical assessment of current process challenges and compare the cost of biogas production via the AD process from the literature, Aspen Plus process modeling, and CapdetWorks software. We also provide insights on critical factors affecting the AD process and recommendations on optimizing the process. We utilize four types of wet wastes, including wastewater sludge, food waste, swine manure, and fat, oil, and grease, to provide a quantitative assessment of theoretical energy yields of biogas production and its economic potential at different plant scales. Our results show that the cost of biogas production from process and economic models are in line with the literature with a potential to go even lower for small-scale plants with technological advancements. This research illuminates potential cost savings for biogas production using different wastes and guide investors to make informed decisions, while achieving waste management goals.

Within the United States and Puerto Rico, publicly owned treatment works (POTWs) process 130.5 Gl/d (34.5 Bgal/d) of wastewater, producing sludge as a waste product. Emerging technologies offer novel waste-to-energy pathways through whole sludge conversion into biofuels. Assessing the feasibility, scalability and tradeoffs of various energy conversion pathways is difficult in the absence of highly spatially resolved estimates of sludge production. In this study, average wastewater solids concentrations and removal rates, and site specific daily average influent flow are used to estimate site specific annual sludge production on a dry weight basis for >15,000 POTWs. Current beneficial uses, regional production hotspots and feedstock aggregation potential are also assessed. Analyses indicate 1) POTWs capture 12.56 Tg/y (13.84 MT/y) of dry solids; 2) 50% are not beneficially utilized, and 3) POTWs can support seven regions that aggregate >910 Mg/d (1000 T/d) of sludge within a travel distance of 100 km. [ABSTRACT FROM AUTHOR]

This work refers to the development of an approach for planning wet waste (food waste and other) collection at a metropolitan scale. Some specific modeling features distinguish this specific waste collection problem from the other ones. For instance, there may be significant differences as regards the values of the parameters (such as weight and volume) characterizing the various collection points. As it happens for classical waste collection planning, even in the case of wet waste, one has to deal with difficult combinatorial problems, where the determination of an optimal solution may require a very large computational effort, in the case of problem instances having a noticeable dimensionality. For this reason, in this work, a heuristic procedure for the optimal planning of wet waste is developed and applied to problem instances drawn from a real case study. The performances that can be obtained by applying such a procedure are evaluated by a comparison with those obtainable via a general-purpose mathematical programming software package, as well as those obtained by applying very simple decision rules commonly used in practice. The considered case study consists in an area corresponding to the historical center of the Municipality of Genoa. [ABSTRACT FROM AUTHOR]

In the present study, the applicability of the wet waste collected from shrimp ( Litopenaeus vannamei) to the culture of sea cucumber ( Stichopus monotuberculatus) was determined. The effects of dietary wet shrimp waste on the survival, specific growth rate (SGR), fecal production rate (FPR), ammonia- and nitrite-nitrogen productions of sea cucumber were studied. The total organic matter (TOM) level in the feces of sea cucumber was compared with that in corresponding feeds. Diet C (50% wet shrimp waste and 50% sea mud mash) made sea cucumber grow faster than other diets. Sea cucumber fed with either diet D (25% wet shrimp waste and 75% sea mud mash) or sole sea mud exhibited negative growth. The average lowest total FPR of sea cucumber occurred in diet A (wet shrimp waste), and there was no significant difference in total FPR between diet C and diet E (sea mud mash) ( P > 0.05). The average ammonia-nitrogen production of sea cucumber in different diet treatments decreased gradually with the decrease of crude protein content in different diets. The average highest nitrite-nitrogen production occurred in diet E treatment, and there was no significant difference in nitrite-nitrogen production among diet A, diet B (75% wet shrimp waste and 25% sea mud mash) and diet C treatments ( P > 0.05). In each diet treatment, the total organic matter (TOM) level in feces decreased to different extent compared with that in corresponding feeds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal carbonization can readily convert paunch waste to value-added products. • Process modelling indicates that pre-heater and dryer are the main energy consumer. • Hydrothermal carbonization technology development is challenged by reactor high cost. • Treating dewatered paunch waste is more commercially viable despite lower conversion. • Economic viability is highly sensitive to LHSV of reactor and economic assumptions. In this study, dewatered and raw paunch waste, with 15 and 3 wt% total solids respectively, generated at abattoirs was hydrothermally carbonised under subcritical water conditions. Higher solids content was found to produce higher hydrochar yield (i.e. 53% for 15 wt% compared to 33.5% for 3 wt%) at similar operating conditions of 10 bar and 240 °C for 5 min. The morphological differences were noted via Scanning Electron Microscopy (SEM) in the hydrochar samples, and the surface area for processing raw paunch waste was found to be 68.1 m2 g−1 compared to 10.8 m2 g−1 in case of dewatered paunch waste. The light bio-oil was mostly composed of phenolic compounds while the heavy bio-oil mainly contained long chain fatty acids and their esters. Following the experimental work, a full-scale ASPEN Plus process model was developed for a typical abattoir generating 27 tonne dry paunch waste per day. Pre-heater and hydrochar dryer contributed to 73% and 57% of the total energy for processing raw and dewatered paunch waste, respectively, because of the high moisture content of the feedstock and hydrochar. After the equipment sizing and estimation of capital and operating costs, the discounted cash flow analysis was performed using the Nth-Plant financing assumptions. It was concluded that treating dewatered paunch waste is preferable as it: needed a smaller reactor i.e. lower overall initial investment, was less sensitive to bio-oil price, and improved the net present value over a period of 30 years to $2.8 MM. Besides the liquid hourly speed velocity, its commercial viability is highly sensitive to internal rate of return and existence of hydrochar dryer. [ABSTRACT FROM AUTHOR]

There are several recent reviews published in the literature on hydrothermal carbonization, liquefaction and supercritical water gasification of lignocellulosic biomass and algae. The potential of hydrochar, bio-oil or synthesis gas production and applications have also been reviewed individually. The comprehensive review on the hydrothermal treatment of wet wastes (such as municipal solid waste, food waste, sewage sludge, algae) covering carbonization, liquefaction and supercritical water gasification, however, is missing in the literature which formed the basis of the current review paper. The current paper critically reviews the literature around the full spectrum of hydrothermal treatment for wet wastes and establishes a good comparison of the different hydrothermal treatment options for managing wet waste streams. Also, the role of catalysts as well as synthesis of catalysts using hydrothermal treatment of biomass has been critically reviewed. For the first time, efforts have also been made to summarize findings on modelling works as well as techno-economic assessments in the area of hydrothermal treatments of wet wastes. The study concludes with key findings, knowledge gaps and future recommendations to improve the productivity of hydrothermal treatment of wet wastes, helping improve the commercial viability and environmental sustainability. • The feasibility of handling wet waste via hydrothermal treatment was reviewed. • Formation of value-added products and reduction of waste volume was proven. • The mechanism and reaction pathways have not been developed enough. • Hydrothermal processing suffers from immature technology, demanding innovations. [ABSTRACT FROM AUTHOR]

• Meat industry waste was treated hydrothermally. • Up to 80% conversion was achieved under mild hydrothermal conditions. • Preservation of carbon in hydrochar during HTC was shown. • Techno-commercial feasibility was studied. Paunch waste is the wet waste generated from the cattle/sheep yard, paunch material, skin-shed, boning rooms, blood stream and rendering plant in an abattoir. It contains around 3% solids. It mainly consists of grass, grain, grease, fat, protein, blood, intestinal content, manure and cleaning products. In this study, paunch waste was treated under hydrothermal carbonisation conditions at different temperatures (160 to 240 ℃), residence time (5–150 min) and initial N 2 pressure (10–30 bar) in a laboratory scale 600 mL Parr reactor system. The main objective of this study was to quantify the product distribution and further characterise the products produced from the hydrothermal carbonisation of paunch waste. The product distribution results reveal that higher bio-oil yield was obtained at relatively mild hydrothermal carbonisation conditions which is mainly attributed to fragile nature of paunch waste, higher water, volatile matter and carbohydrate content, and lower lignin and ash content. The resultant hydrochar was found to have higher HHV (∼24.48 M J k g - 1) and BET surface area (68.1 m 2 g - 1) which demonstrates their suitability as a coal substitute (in energy generation processes) or a porous medium (in soil conditioning, remediation or catalysts applications). Biodiesel-like compounds were found in the heavy bio-oil with the HHV of around 38 M J k g - 1. Higher bio-oil production and excellent physico-chemical properties of hydrochar at milder hydrothermal carbonisation conditions have demonstrated significant improvement in the commercial viability of hydrothermal carbonisation of the paunch waste. [ABSTRACT FROM AUTHOR]

As the demand for utilizing environment-friendly and sustainable energy sources is increasing, the adoption of waste-to-energy technologies has started gaining attention. Producing biogas via anaerobic digestion (AD) is promising and well-established; however, this process in many circumstances is unable to be cost competitive with natural gas. In this research, we provide a technical assessment of current process challenges and compare the cost of biogas production via the AD process from the literature, Aspen Plus process modeling, and CapdetWorks software. We also provide insights on critical factors affecting the AD process and recommendations on optimizing the process. We utilize four types of wet wastes, including wastewater sludge, food waste, swine manure, and fat, oil, and grease, to provide a quantitative assessment of theoretical energy yields of biogas production and its economic potential at different plant scales. Our results show that the cost of biogas production from process and economic models are in line with the literature with a potential to go even lower for small-scale plants with technological advancements. This research illuminates potential cost savings for biogas production using different wastes and guide investors to make informed decisions, while achieving waste management goals.