Food Waste Disposal Research Articles

Fabrication of hydrochar based on food waste (FWHTC) and its application in aqueous solution rare earth ions adsorptive removal: Process, mechanisms and disposal methodology

Hydrothermal carbonization (HTC) of food waste is a promising technology to dispose these widely generated and notorious wastes. Food waste hydrochar (FWHTC) was produced during this process. However, production and application of FWHTC remained at embryo stage. Herein, this study for the first time produced leftover steamed bread hydrochar (LSHTC) and pitaya peel hydrochar (PPHTC), and then applied them to adsorptive remove rare earth ions (REI) from wastewater. FWHTCs were systematically characterized by SEM, FTIR, XPS, BET, elemental analysis and TG-DSC. Isotherm study showed that Langmuir model fitted the data well at lower initial REI concentrations while Freundlich model fitted better at higher concentrations. The maximum adsorption capacity of LSHTC for La3+ reached 108 mg g−1. Continuous adsorption experiment in adsorption column was also conducted and key operation parameters were predicted by Yoon-Nelson model. The adsorption mechanisms were dominated by physisorption (electrostatic attraction) at the very starting stage, followed by chemisorption (ion exchange and/or surface complexation) playing a key role. At last, a sustainable “Reduce-Reuse-Recycle” pattern of food waste disposal methodology was proposed.

Vanadium and chromium-contaminated soil remediation using VFAs derived from food waste as soil washing agents: A case study

Food waste (FW) is environmentally unfriendly and decays easily under ambient conditions. Vanadium (V) and chromium (Cr) contamination in soils has become an increasing concern due to risks to human health and environmental conservation. Volatile fatty acids (VFAs) derived from FW was applied as soil washing agent to treat V and Cr-contaminated soil collected from a former V smelter site in this work. The Community Bureau of Reference (BCR) three-step sequential extraction procedure was used to identify geochemical fractions of V and Cr influencing their mobility and biological toxicity. Optimal parameters of a single washing procedure were determined to be a 4 h contact time, liquid–solid ratio of 10:1, VFAs concentration of 30 g/L, and reaction temperature of 25 °C, considering for typical soil remediation projects and complete anaerobic fermentation of FW. Under the optimal conditions, butyric acid fermentation VFAs attained removal rates of 57.09 and 23.55% for extractable fractions of V and Cr, respectively. Simultaneously, a multi-washing process under a constant liquid–solid ratio using fresh and recycled VFAs was conducted, which led to an improvement on the total removal efficiency of toxic metals. The washing procedure could reach the pollution thresholds for several plants, such as of S. viridis, K. scoparia, M. sativa, and E. indica. This strategy enhances the utilization of VFAs derived from food waste, has a positive effect on V and Cr-contaminated soil remediation, wastewater control of soil washing and FW disposal.

A system dynamics model for evaluating food waste management in Hong Kong, China

Of landfilled municipal solid waste in Hong Kong, 33.2% is attributed to food waste. The government has set a waste reduction target to reduce by 40% the current food waste disposal at landfills by 2022 and has launched various policies and strategies to achieve this target. The Hong Kong Government is eager to control the utilisation level of food waste through various policies and the food waste conversion by a newly adopted Organic Waste Treatment Facility. In this study, the current landfill situation and the effectiveness of food waste policies are investigated using a system dynamics approach to study the dynamics and interrelationships in food waste management. The model is used to forecast the effectiveness of the food waste management in different scenarios. Among these scenarios, adopting Organic Waste Treatment Facility and implementing a quantity–volume-based charging scheme are examined. Although improvements are expected to be made after implementing these policies when compared to the current trends, the model output indicates that without any other new policy or action plan, it is difficult to achieve the objectives set by the government. Suggestions are made so as to improve the effectiveness of food waste management in the future.

Environmental-Economic Analysis of Integrated Organic Waste and Wastewater Management Systems: A Case Study from Aarhus City (Denmark)

This study presents a comparative analysis of the environmental and economic performances of four integrated waste and wastewater management scenarios in the city of Aarhus in Denmark. The purpose of this analysis is to deliver decision support regarding whether (i) the installation of food waste disposers in private homes (AS1) or (ii) separate collection and transport of organic waste to biogas plants is a more viable environmental and economic solution (AS2). Higher environmental benefits, e.g., mitigation of human health impacts and climate change, are obtained by transforming the existing waste combustion system into scenario (ii). Trade-offs in terms of increased marine eutrophication and terrestrial ecotoxicity result from moving up the waste hierarchy; i.e., from waste incineration to biogas production at wastewater treatment plants with anaerobic sludge digestion. Scenario (i) performs with lower energy efficiency compared to scenario (ii). Furthermore, when considering the uncertainty in the extra damage cost to the sewer system that may be associated to the installation of food waste disposers, scenario (ii) is the most flexible, robust, and less risky economic solution. From an economic, environmental, and resource efficiency point of view, separate collection and transport of biowaste to biogas plants is the most sustainable solution.

Application of lactic acid derived from food waste on pathogen inactivation in fecal sludge: a review on the alternative use of food waste.

Food waste generation and disposal have led to several environmental problems, especially in developing countries. This phenomenon is partly because most cities rapidly urbanize, which results in population increase, urban settlement and waste generation. Improper management of waste has continued to create environmental problems. These problems have indeed interfered with the inadequate measures in managing other organic waste such as food waste. Food waste can be fermented and used for pathogen inactivation in fecal sludge (FS). The continual decrease in global crop production due to soil erosion, nutrient runoff and loss of organic matter has generated interest in using FS for soil amendment. However, due to the high number of pathogens in FS that are harmful to humans, FS must be treated before being used in agriculture. Thus, given the high amounts of food waste generated globally and the lactic acid potential of fermented food waste, several researchers have recently proposed the use of fermented food waste to suppress pathogens in FS. This review presents the various approaches in pathogen inactivation in FS using different types of food waste. On the basis of the literature review, the major problems associated with the generation, collection and application of food waste in pathogen inactivation in FS are discussed. Moreover, the trends and challenges that concern the applicability of each method are critically reviewed.

Nutrients removal performance and sludge properties using anaerobic fermentation slurry from food waste as an external carbon source for wastewater treatment

Enhancement of nitrogen and phosphate removal using thermophilic fermentation slurry from food waste (FSFW) as external carbon source was investigated. Based on the batch tests, the soluble and particulate fractions of the FSFW acted as easily and slowly biodegradable carbon sources, respectively, and the fermented slurry showed the combined nutrients removal properties of soluble and solid organics. During the long-term operation of a sequencing batch reactor (SBR) with FSFW for wastewater treatment, the sludge particle size increased obviously, the bacterial metabolic capacity improved significantly, and some functional microorganisms were enriched selectively, which significantly promoted the nitrogen removal efficiency (approximately 90%) by enhancing the anoxic denitrification and simultaneous nitrification and denitrification (SND) processes. Moreover, high phosphate removal efficiency (above 98%) was achieved through the aerobic and anoxic phosphate accumulation processes. Thus, using the FSFW as supplementary carbon source is a suitable solution for both food waste disposal and wastewater treatment.

Global trends and future prospects of food waste research: a bibliometric analysis.

The unregulated discharge reams of food waste (FW) causes severe resource loss and environmental pollution. In the present study, a bibliometric analysis was used for research activities and tendencies of food waste from 1991 to 2015. The results indicated that the amount of FW research continually grew by the years, and the number of publications rose significantly from 2012. Bioresource Technology and Waste Management were the two most frequently published journals in the field of FW research. China took a leading position and had a high h-index (38) out of 94 countries/territories, followed by the USA and South Korea. Presently, anaerobic digestion for methane and dark fermentation for hydrogen production are the mainstream techniques in FW disposal. Lactic and ethanol fermentation from FW received more and more attention in recent years. Life cycle assessment (LCA) was an ever-increasingly popular evaluation method for FW-related research. Moreover, cluster analysis indicated microbial community structure, food security, leachate, and pathogens were also the research hotspots.

A multi-criteria sustainability assessment framework: development and application in comparing two food waste management options using a UK region as a case study.

Preventing food wastage is a key element of sustainable resource management. But as food waste is still generated at high volumes, priority is placed on its proper management as a resource, maximising sustainability benefits. This study, by integrating a multi-criteria decision analysis with a sustainability assessment approach, develops a screening and decision support framework for comparing the sustainability performance of food waste management options. A structured process for selecting criteria based on the consideration of environmental, economic and social aspects related to region-specific food waste system planning, policy and management has been developed. Two food waste management options, namely the use of food waste disposal units, which grind food waste at the household's kitchen sink and discharge it to the sewer, and the anaerobic co-digestion of separately collected food waste with sewage sludge, were selected for comparison due to their potential to create synergies between local authorities, waste and water companies, with local circumstances determining which of the two options to adopt. A simplified process used for assessing and comparing the two food waste management options in the Anglian region in the UK, indicated that there are benefits in using the framework as a screening tool for identifying which option may be the most sustainable. To support decision-making, a detailed analysis that incorporates stakeholders' perspectives is required. An additional use of the framework can be in providing recommendations for optimising food waste management options in a specific region, maximising their sustainability performance.

The quantity of food waste in the garbage stream of southern Ontario, Canada households.

There is little consensus on the amount of worldwide food waste generation because many current estimates are indirect and link back to the same limited primary datasets, with much of the data originating from fieldwork undertaken in the 1970s and 1980s. Direct measurement of waste streams, through waste composition studies, can be used to develop accurate estimates of food waste disposal. In Ontario, Canada, municipalities that undertake household waste composition studies all use a common direct measurement methodology that includes a broad range of waste categories, including food waste. The purpose of this research was to estimate the quantity of food waste disposed, in the garbage stream, by households in southern Ontario, Canada, and determine if this common methodology could be expanded and serve as the basis of a standardized and rigorous household food waste measurement methodology. Household waste composition study data (2012–2015), including a single “food waste” category, were gathered from 9 Ontario municipalities, aggregated and analyzed to develop estimates of food waste in the garbage stream. On average, households disposed 2.40 kg/week of food waste in the garbage, which comprised 35.4% of this waste stream. This does not include any food waste otherwise disposed (e.g., sink) or recycled (e.g., composted). Urban households disposed significantly greater amounts of food waste compared to rural households in the spring (p = 0.01) and summer (p = 0.02). Households with access to a green bin program disposed significantly less food waste than those with no access to a green bin program in the spring (p = 0.03) and summer (p<0.01). The common methodology used to develop these estimates shows promise as the basis of a household food waste measurement methodology. This future methodology would include dividing food waste into avoidable and unavoidable food waste categories, as well as adding subcategories (e.g., avoidable fruits and vegetables).

Single phase blend: An advanced microwave process for improved quality low-cost biodiesel production from kitchen food waste

Accumulation and disposal of kitchen food waste is a substantial environmental issue due to the absence of appropriate reuse techniques. The present study developed a low-cost biodiesel production method and used Taguchi optimization technique to improve FAME yield. A single phase blend (oil, co-solvent and solvent mixture) was prepared and subjected to microwave irradiation to accelerate the initial slow reaction rate. Transesterification was carried out in a closed vessel under various temperature-pressure conditions. The reaction parameters were optimized through Taguchi model. Maximum FAME yield of 96.89 wt% was achieved at microwave cell pressure: 2.2 MPa, temperature: 170 °C, reaction time: 4 min and catalyst concentration: 0.5 wt% with single phase blend ratio 1:6:30 (oil: co-solvent: methanol). Methyl tert-butyl ether (MTBE) was used as co-solvent that contributed to maximum FAME conversion and produced glycerol tert-butyl ether (GTBE), a useful fuel additive as a byproduct. Improved cetane number observed for the kitchen food waste derived biodiesel signifies the fuel of superior fatty acid structure. Maximum 85 wt% GTBE conversion was attained at 200 °C temperature and cell pressure 3.9 MPa at 10 min reaction time. Microwave irradiation method consumed 2.7% lesser energy than conventional heating method.

Verification of the Effectiveness of Price Presentation Considering Consumer's Purchasing Behavior by Smartphone Application for Reducing Food Waste Disposal

In recent years, food waste disposal, food loss has become a social problem. Among them, attention is focused on reducing food loss. Food loss refers to the disposal of parts that were originally available for eating during food disposal. Food losses are targeted for residues left behind, excessive removal, expiration of expiration dates and the like in the home. On the other hand, disposal due to expiration of expiration dates at retail stores is treated as food disposal. We made proposals for pricing by smartphone application to reduce food loss. The penetration rate of smartphones has become about 65%, and in the age of 20 to 50 years it is high as around 80%, so it can appeal to many consumers. In this paper, we verify that price presentation considering consumer's purchasing behavior by smartphone application is effective.

Household food waste disposal in South Africa: A case study of Johannesburg and Ekurhuleni

Food waste is becoming an important issue in light of population growth and global food security concerns. However, data on food wastage are limited, especially for developing countries. Global estimates suggest that households in developed countries waste more food than those in developing countries, but these estimates are based on assumptions that have not been tested. We therefore set out to present primary data relating to household food waste disposal for South Africa within the sub-Saharan African context. As the Gauteng Province contributes about 45% of the total municipal waste generated in South Africa, the case study area covers two of the large urban metropolitan municipalities in Gauteng, namely Ekurhuleni and Johannesburg, with a combined population of 8.33 million, representing nearly 15% of the South African population. Municipal solid waste characterisation studies using bulk sampling with randomised grab sub-sampling were undertaken over a 6-week period during summer in 2014 (Johannesburg) and 2016 (Ekurhuleni), covering a representative sample of the municipal waste collection routes from households in each of the two surveyed municipalities. The food waste component of the household waste (excluding garden waste) was 3% in Ekurhuleni and 7% in Johannesburg. The results indicate that an average of 0.48 kg (Ekurhuleni) and 0.69 kg (Johannesburg) of food waste (including inedible parts) is disposed of into the municipal bin per household per week in the two municipalities, respectively. This translates into per capita food waste disposal of 8 kg and 12 kg per annum, respectively, in South Africa as compared to the estimated 6–11 kg per annum in sub-Saharan Africa and South and Southeast Asia. &#x0D; Significance:&#x0D; &#x0D; Research on food waste in developing countries is limited.&#x0D; This study is the first of its kind undertaken in South Africa.&#x0D; Food waste research is important to address food security issues.&#x0D; This study provides evidence to support Sustainable Development Goal 12.3.&#x0D;

Greenhouse gas emissions of food waste disposal options for UK retailers

Food retailers are under increasing political and social pressure to reduce both the amount of food that they waste and the amount of greenhouse gases (GHGs) that their food retailing activities incur. For completeness, when assessing the ‘carbon footprint” of their business activities, food retailers should also included the greenhouse gas emissions caused by their disposal of waste food, which will vary with the waste disposal option used. However, there is lack of quantitative guidance for food retailers on the net GHG emissions that are incurred in the disposal of specific food types by the various disposal options available. Here, we calculate the net GHG emissions of eight different waste disposal options for five core food types using life cycle assessment, accounting for both emissions incurred in transport and processing, and those mitigated by the creation of useful products. We also assess the extent to which the embodied emissions in waste foods at the retail checkout can be mitigated by each disposal option. In addition to food specific results, we calculate mass-weighted averages using data from a mid-sized retail chain. We find a strong correlation between net emissions and the energy density of foods, and the following mass weighted disposal hierarchy (from best to worst, with respect to greenhouse gas emissions): donation of edible food to food banks; anaerobic digestion; conversion to animal feed; incineration with energy recovery; aerobic composting; landfill with gas collection and utilisation; landfill with gas collection and flaring; landfill without gas collection. If waste food from retailers is unfit for human consumption, to minimise greenhouse gas emissions it should be disposed of by conversion to animal feed or anaerobic digestion. For all food types, landfill is the worst disposal option.

Life cycle environmental and economic analysis of regional-scale food-waste biogas production with digestate nutrient management for fig fertilisation

Abstract Small-scale biomethane production is a promising option to meet a domestic energy supply in Thailand. As part of domestic energy policies in Thailand (new Alternative Energy Development Plan), a biogas plant with 400 kg-wet/d capacity manufactured by Japanese companies was installed at a university in Thailand in 2013. For sustainable operation of the plant, the primary energy demand (PED) and life-cycle greenhouse gas (GHG) emission associated with well-to-tank, WTT (the food waste transport, conversion to biomethane and biomethane storage) are assessed. GHGs emission associated with well-to-wheel, WTW (the food waste transport, conversion to biomethane, biomethane storage and driving fuelled by the biomethane) are revealed. Economic analysis is also implemented based on the actual operating data including digestate price derived from N-P-K nutrient management (0.2689 THB/kg), and payback time sensitivity analysis. Primary energy demand associated with WTT processes was 0.68 MJ/MJ-CH4. GHG emission from WTW processes is 132.0 kg-CO2eq/km, which is less than one third that of the other biofuels (biohydrogen, biomethanol, bio-dimethylether and Fischer-Tropsch diesel). The economic analysis showed that food waste disposal income and electricity sales are hot spot in the revenue and interest payment and maintenance cost has high impact in expenditure. The most sensitive parameter is biomethane yield, which should be kept higher for profitable operation of the biogas plant in Thailand.

Enhanced lipid production and nutrient utilization of food waste hydrolysate by mixed culture of oleaginous yeast Rhodosporidium toruloides and oleaginous microalgae Chlorella vulgaris

Abstract Using food waste hydrolysate as medium for culturing oleaginous microorganism is a dual-purpose strategy for relieving environmental burdens both in food waste disposal and energy crisis. The pure culture of one oleaginous microorganism when single waste as culture media has shortages such as high operation cost, low lipid production and low substrate utilization. Mix-culture of yeast and microalgae in this work enhanced this process result in better waste treatment, higher lipid production and shorter cultivation time. Compare to pure culture of Rhodosporidium toruloides, the nitrogen utilization rate, reducing sugar utilization rate and lipid production increased by 23%, 17% and 12%, respectively, and the cultivation time shorten by 40%, in mix-culture of Rhodosporidium toruloides and Chlorella vulgaris. The results showed that the mix-culture of yeast and microalgae using food waste hydrolysate as culture medium would be a good strategy for both waste disposal and biofuel production.

Carbon footprint of integrated waste management systems with implications of food waste diversion into the wastewater stream

This paper introduces a comprehensive model developed to assess the carbon footprint of integrated solid waste management systems including the diversion at source of the food waste component into the wastewater/sludge management systems using household food waste disposers. In addition to the current state of practice in developed economies, the model includes emissions from waste management processes still practiced in developing economies (such as open dumping, open burning, poorly operated landfills with flaring systems and auxiliary fuel needed to satisfy the low heating value (LHV) during incineration) commonly not considered in most life cycle assessment (LCA)-based models. It can disaggregate emissions by source (from collection to final disposal), or type (direct-operating, indirect-upstream, indirect-downstream), or gas (CH4, CO2, N2O) and offers users the flexibility to select processes or modify input parameters while examining their impact on uncertainty in model simulations. Equally important is a clarity in deriving and applying emission factors used to quantify emissions from waste management systems. The model was tested in the context of developed and developing economies to assess the impact of waste composition, management processes, energy consumption and other parameters on variations in emissions. The results demonstrated that best practices through material recycling, biological treatment, food waste diversion, and/or energy recovery can contribute to significant savings in emissions that ranged between 24 and 95%, depending on the tested systems. In closure, we argue the benefits of the model application in providing guidelines for policy planning and decision making about process viability for investing in carbon credit.

Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial population dynamics

Abstract An anaerobic membrane bioreactor (AnMBR) pilot plant treating kitchen food waste (FW) jointly with urban wastewater was run for 536 days. Different operational conditions were tested varying the sludge retention time (SRT), the hydraulic retention time (HRT) and the penetration factor (PF) of food waste disposers. COD removal efficiency exceeded 90% in all tested conditions. The joint treatment resulted in an almost 3-fold increase in methane production (at 70 days of SRT, 24 h HRT and 80% PF) in comparison with the treatment of urban wastewater only. Mathematical model simulations and Illumina technology were used to obtain in-depth information of this outstanding process performance. Both the PF and SRT factors increased influent biodegradability. The experimental results were accurately reproduced via model simulations modifying only the influent biodegradability. The high SRT and the presence of ground FW in the influent resulted in higher hydrolytic activity. Not only did the Archaea population increase 3-fold but Levilinea genera was also significantly raised. Three new genera characterised by anaerobic fermentation of amino acids (Leptolinea, Aminomonas and Aminobacterium) were among the ten most abundant of the total sequences identified during the joint treatment, indicating an improvement in the hydrolysis step of anaerobic degradation. Influent biodegradability remained at high values when FW addition stopped.

Carbon Footprint of an Organization: a Tool for Monitoring Impacts on Global Warming

Abstract Recently, global warming has become one of the major topics to be considered by the world community. Considerable evidence exists to prove that the highest portion of this warming is caused by anthropogenic activities. Calculating Carbon Footprint (CFP) is the valuable first step towards making quantifiable emission reduction because it denotes how human react on global warming as a person, organization, country and world. Different types of organizations such as universities, fire brigades, rescue services, food manufacturers, hotels, hospitals have estimated their CFP nowadays. Among these organizations, Divisional secretariat offices play a major role for the general public as the main government organizations in the country. Therefore, main objectives of this study were to assess the CFP of a divisional secretariat office in Thihagoda in southern Sri Lanka and suggest suitable methods for reducing their CFP. After defining the organizational and operational boundaries according to Green House Gas (GHG) protocol using three scopes 1, 2 and 3, CFP of each emission sources and activities were calculated in tCO2e/year by multiplying activity data with emission factors (EF). Emission factors were developed according to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Activity data were collected from bills, data sheets, personal communication and questionnaire for transportation by company own vehicle, food waste disposal, usage of liquid petroleum gas (LPG), backup generator (scope 1), for purchased electricity (scope 2) and for employee commuting and usage of water (scope 3). The results show that total CFP of this organization is 36.09 tCO2-e/year, which is comparatively less than other organizations in Sri Lanka. The CFP under scope 1, 2, and 3 are 25.3%, 17.7% and 57.1% of the total respectively. Since the highest percentage of CFP depicts under scope 3 and it is due to employee commuting (56.73%), employees should be encouraged to use public transportation rather than private transportation.

A Study on Smart Monitoring and Automatic Control based Food Waste Disposer

A Study on Smart Monitoring and Automatic Control based Food Waste Disposer

The characteristics of household food waste in Hong Kong and their implications for sewage quality and energy recovery

Food waste (FW) is a worldwide environmental issue due to its huge production amount. FW separation from municipal solid waste followed by different treatment strategies has been widely accepted. Food waste disposer (FWD) is a promising approach to separate and collect household food waste (HFW), which has been widely applied in many countries. However, the feasibility of FWD application in many countries is still being debated due to the major concerns over the impact of FWD on the wastewater treatment plants. In order to investigate the feasibility of FWD application, FW characterization is a key work to be conducted in advance. Since the FW characteristics largely vary by region, reliable and representative FW characteristics in different countries should be investigated. To provide such information for further studies on FW management for Hong Kong, HFW was collected from Hong Kong typical households over one year and analyzed systemically in this study. The FW composition varied little from place to place or season to season, and the values observed were comparable with results reported from other countries and regions. Based on the reliable HFW characteristics obtained from one-year survey coupled with statistical analysis, simulated HFW for Hong Kong consisting of 50% fruits, 20% vegetables, 20% starchy food and 10% meat was proposed for future studies. On the other hand, the FWD treatment caused more than 50% of the biodegradable organic content in HFW to dissolve. With a ratio of 1 g food waste to 1 L sewage, total solids in the wastewater stream were predicted to increase by 73%, total chemical oxygen demand by 61%, soluble chemical oxygen demand by 110%, nitrogen by 6% and phosphorus by 16%. Theoretically, 22 million m3/year of additional methane could be generated if 50% of Hong Kong residential buildings equipped with FWD. That would certainly increase pollutant loading on the wastewater treatment plants, but also energy recovery potential.