Session 18 - Solid waste management

In Greece, approximately 1.8 million tonnes of food waste are generated each year, mostly disposed of in landfill. Food waste is of concern for businesses in the hospitality and food service sectors, which in Greece dispose of an estimated 100,000 tonnes of food waste annually, almost 6% of the total food waste generated in Greece.
The food waste composition analysis and generation rate were determined through Waste Analysis Campaigns (WACs). It is in the scope of the present work to illustrate the results of food waste compositional analysis on samples from the study area of the targeted hotels of Heraklion and Hersonissos in the Region of Crete. The increased need for food waste diversion from landfill and the existing policy which promotes its separate collection and treatment necessitates the comprehensive characterisation of food waste in order to fill information gaps and uncertainties towards food waste management improvements.
The ‘Fresh Fruits’ and ‘Fresh Vegetable and Salads’ represented the greatest proportions (56.5%) in each WAC for the hotels. A certain degree of variability is observed though due to seasonal variation.
The recorded low impurities content (~0.6%) demonstrate that the participating hotels practice effectively the source separation of the generated food waste.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:15 to 16:30
Oral presentation in Solid waste management

Restaurants, food processing industries and café kitchen generate significant amounts of food waste (FW) and waste cooking oil. Septage treatment also generates large amount of biosolids. This study explores the application of anaerobic process, which generates methane, a renewable energy resource, to these wastes. The performance of batch anaerobic co-digestion of food waste, biosolids and waste cooking oil at varying waste ratio, namely 0, 30, 50 and 70 mass percent volatile solids (VS) was determined. The seed sludge used was a combination of cow rumen obtained from a slaughterhouse and pig manure. The waste mixture that did not contain waste oil yielded the highest amount of methane (61.5 mL g-1 VS), showed the highest VS destruction (48.51%) and rate of hydrolysis (first-order rate constant of 0.187 d-1). Rates of hydrolysis and methane production, methane yield and methane content of the biogas produced were lower at higher amounts of oil added but constant amount of seed sludge. Nevertheless, the mixture containing 70% waste oil produced 9.54 mL g-1 VS. Compared with other simple means of disposal, this method of the three kinds of wastes is a promising energy-generating option for treating food waste.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:00 to 16:15
Oral presentation in Solid waste management

Landfill is generally believed to have higher greenhouse gas emissions than composting or waste-to-energy. The EU Landfill Directive requires nations to progressively divert biodegradable waste away from landfill. Waste disposal in landfill is at the bottom of its Waste Hierarchy. Many nations also ban landfilling of plastic. These policies may inadvertently increase global warming by increasing incineration. In Europe, Waste-to-Energy (WTE) incineration emits 72,000,000 tonnes of fossil CO2 a year, increasing yearly. Landfill methane is now generally captured. Nations that directly measure landfill gas emissions (the UK, Ireland and USA) now report about 65- 75% landfill gas recovery; the average for California is 79%. It is now almost always used to generate electricity. When burnt it does not emit fossil CO2. Landfill is a carbon sink, sequestering about half of the organic carbon deposited in it, long-term, like peat. This reduces the global flux of CO2.

Session: 18, Room: F, at Thu, 09/05/2019 - 17:06 to 17:09
Flash presentation in Solid waste management

The problem on solid waste has been and still remains as a major problem in the Philippines especially in developing countries where proper facilities for collection and disposal are not always available. In Metro Manila alone, daily waste generation stands at 8,600 tons coming from a population 12.8M. The infrastructure has already reached its maximum capacity resulting to major upsets in environmental quality. The sheer volume of solid waste generated daily poses a big challenge for disposal options since reuse and recycling methods are the only the socially acceptable options. Incineration though not strictly banned by law has never been initiated apparently due to lack of a scientific understanding of the process and its appreciation as a safe and viable process of handling solid waste. Meanwhile, depletion of available capacities of sanitary landfills proceeds at an accelerated phase because of the sheer volume of solid waste to be disposed compounded by the reluctance to implement waste to energy options of waste disposal. In a bid to address the issue, the Philippine Congress legislated a law to require all local government units (LGU) in the country to develop a comprehensive solid waste management plan. Notwithstanding these efforts, the problem remains far from over. The volume of waste ending up in the landfill continues to be the dominant concern.

Session: 18, Room: F, at Thu, 09/05/2019 - 15:00 to 15:15
Oral presentation in Solid waste management

Limited attention has been paid to health-care waste management despite an increase in public concern about the management of such waste on a global basis. The objective of this study was to analyse the issues and challenges of health-care waste management as well as possible solutions. It is estimated that about 50% of the world’s population is at particular risk from improperly treated health-care waste. In most countries wastes from hospitals and other health-related facilities are not required to be treated to remove the thousands of high-volume health-care chemicals. Incomplete removal can lead to formation of transformation products which in some cases may be more toxic than the parent compounds. Uptake of contaminants by earthworms and plants may contribute to biomagnification in terrestrial food web, and thus, their food-chain effects need attention. Humans can be exposed to chemicals through the consumption of contaminated water and food. Stewardship and green pharmacy have the potential to deliver positive environmental health. The whole life cycle of a compound or health-care product has to be considered when making risk management and risk reduction decisions. Such life-cycle assessment can be made by various stakeholders in the health-care chain, including manufacturers, doctors, pharmacists, and patients.

Session: 18, Room: F, at Thu, 09/05/2019 - 17:00 to 17:03
Flash presentation in Solid waste management

Cochin, the commercial and industrial centre of Kerala, lies on the south-west coast of Arabian sea. It covers an area of 94.88 Km2. There are two major dumpsites in the city, one at Brahmapuram and other at Kalamassery. The proper management of the waste has been a challenging task for the concerned authorities. One of the cost-effective combating ways is the use of microbes. A preliminary attempt was performed to quantify both the physicochemical and microbial characteristics of the dumpsite soils and evaluated by using standard techniques. The soil samples from the study sites showed higher values for bacterial and fungal counts than the control soils. Some of the isolated species belonged to the genera Bacillus, Pseudomonas and Klebsiella. As the findings reveal that the dumping site soils have wide microbial diversity which can be exploited for sustainable and eco-friendly bioremediation approach.

Session: 18, Room: F, at Thu, 09/05/2019 - 17:03 to 17:06
Flash presentation in Solid waste management

This paper is focused on the utilization of Recycled concrete aggregate (RCA) as a substitute for natural aggregate. Concrete produced in this way is characterized by worse properties than standard concrete, mainly due to the properties of the RCA. One option is to modify the surface of the RCA and thereby to improve the properties of the concrete as a whole. By the method described in this paper, we have succeeded in reducing the total water absorption of concrete by 50%, while the compressive strengths on the tested cubes with the edge 100 mm were 55 MPa.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:57 to 17:00
Flash presentation in Solid waste management

This study is focused on a technologically viable approach to obtain zeolite Na-X by aging of lignite coal fly ash (FA) in alkaline solutions at ambient conditions resembling a quasi natural crystallization process. Reaction products were characterized for their phase composition by X-ray diffraction, morphology by scanning electron microscopy (SEM) and surface properties by nitrogen adsorption/desorption isotherms. The effect of the crystallization time was investigated as an important parameter for the extent of zeolitization. The highest yield of zeolite Na-X was achieved by incubating FA in 1.5 mol/l NaOH for one year. However, significant crystallization extent is established after eight months of alkaline aging. Fly ash zeolites (FAZ) obtained by atmospheric crystallization have specific surface values up to 280 m2/gFAZ.

Session: 18, Room: F, at Thu, 09/05/2019 - 15:45 to 16:00
Oral presentation in Solid waste management

The article draws attention to the problem of the presence of selected metals in waste electrical, electronic equipment (WEEE). These metals belong to the group of critical metals (germanium), strategic metals (tellurium) and highly toxic elements (thallium). Due to low content of these metals in e-waste, they are usually ignored during e-waste analysis, therefore they belong to the least-known metals in the literature regarding waste recycling. Their presence in WEEE can cause them to be concentrated in the environment during improper e-waste processing. The article presents the applications of Ge, Te, Tl in electronic equipment, quantities identification of these metals in a variety of electronic equipment elements, paying special attention to the ability to accumulate/concentrate Ge, Te, Tl in individual fractions after the e-waste shredding and grinding process This research aims to determine possibility getting of these metals into the environment, during the storage and processing of e-waste (especially in the unit processes of disassembly, separation, shredding), in the case of uncontrolled electronic waste handling and disposal.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:54 to 16:57
Flash presentation in Solid waste management

A method aiming at improving source-separation performance of household food waste (FW) was investigated in two areas with different socio-economic characteristics in Lübeck, Germany. This included the test of a new FW collection system including the distribution of small collection buckets to each household. In addition, an information event was organized and households were provided with information material including a waste sorting guide. The study also aimed at assessing the FW avoidance potential. A method for waste composition analysis for FW from households was applied for the assessment. Both areas showed an increase of the source-separation of FW from 17.4% to 60.3% (A, socio-economic low area) and from 16.6% to 65.7% (B, socio-economic medium area) respectively. Compared to the waste composition in the bio-waste (BW) bin prior the investigation, macro-impurities (including paper waste) reduced from around 6.1% to 0.6% (A) and from 13.6% to 1.2% (B). In this respect, the investigated collection system showed a significant improvement to the regular waste collection system.

Session: 18, Room: F, at Thu, 09/05/2019 - 15:30 to 15:45
Oral presentation in Solid waste management

Nowadays polyethylene is one of the polymers produced in the greatest volume, therefore, parallelly the amount of generated waste polyethylene (w-HDPE) significant as well. Valorisation and recycling of w-HDPE can be realized by blending with different types of polymers and/or elastomers in order to result in thermoplastic elastomer end-product for example. One potential candidate can be ethylene-vinyl acetate (EVA) nevertheless interfacial interaction between w-HDPE and EVA is inadequate reflected in deterioration of mechanical properties of the blend in spite of the fact that they possess favourable mechanical properties themselves and they may complement each other. For the purpose of boosting of interfacial interactions between these two polymers experimental olefin-maleic-anhydride based additives have been incorporated in the blends after optimization of the processing temperature. Impact and tensile tests have been carried out in our research work besides microscopy measurements and investigation of the effects of additive structure by FT-IR and rheology.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:30 to 16:45
Oral presentation in Solid waste management

The treatment and processing of coffee annually produces a large volume of biological waste, which contributes to environmental pollution, it is estimated that coffee production generates approx. 6 million tonnes of spent coffee grounds per year in the world (GETACHEW and CHUN, 2017). Thus, the sludge becomes a residue equivalent to approximately 50% of the roasted coffee in the soluble coffee industry (PUJOL D. et al. 2013). The major problem of the discharge of spent ground coffee in the environment is the presence of caffeine and phenolic compounds when in concentration above 2.5% due to toxicity to plants and soil microorganisms. Therefore, this project proposed to extract the oil from the coffee grounds using the ultrasound method as a pre-extraction method to the soxlet extractor, aiming at eliminating the environmental contamination of the residue and at the same time adding value through the study of the oil for use in cosmetics due to the high amounts of phenolic compounds and antioxidants. The results showed that the application of the ultrasound as a pre-extractive method during 30 min allowed to increase the oil quantity by 70% in relation to the use of the soxlet extractor only, maintaining the quality of the composition.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:51 to 16:54
Flash presentation in Solid waste management

Food waste or leftovers generated by various raw or processed food materials that are not consumed but instead are usually disposed to waste landfills are regarded as a global issue which impacts human health and environmental sustainability. An enormous pressure in disposing of food wastes in landfill sites already exists and is predicted to be increased during the forthcoming years whereas simultaneously various environmental problems associated with solid wastes have to be solved. On the other hand, a percentage higher than 60% of the operational costs of any modern aquaculture industry concerns the supplies of protein-enriched- aquafeeds which among other characteristics are commercially manufactured sources of additional healthy nutritious and digestible proteins that tend to be expensive. Recent research and published data evaluating the use of recycled food wastes as a partial replacement of fishmeal-based feeds in diets of several species suggest that this can be considered as a more sustainable and environmentally friendly practice.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:48 to 16:51
Flash presentation in Solid waste management

Several residues and carbohydrate-rich effluents have been studied as a possible alternative in the substitution or implementation of the traditional cultivation medium of xanthan gum, helping in the management of these residues and, consequently, reducing fermentation costs. This work studied the extract obtained from potato peels for xanthan gum production by fermentation with or not sucrose supplementation. Xanthan gum yield ranged between 2-4 g L-1, and a linear relationship between the amount of added sucrose and gum produced was observed. In addition, the peak of gum production with higher viscosity was able to be anticipated with the sucrose supplementation, from 72 to 24 h (with the 5% of sucrose in comparison with the control condition). The maximum viscosity was 950 mPa.s, a result higher than many published papers that use residues as culture medium for xanthan production.

Session: 18, Room: F, at Thu, 09/05/2019 - 16:45 to 16:48
Flash presentation in Solid waste management

Bottom ash (BA) is the dominant residue from municipal solid waste or refuse-derived fuel incineration. Disposal costs chiefly depend on the leachability of trace metals and salts. The mobility of these constituents is classically minimized by ageing for several months. Ageing involves the oxidation of metals, dissolution and precipitation reactions, and most importantly, car-bonation of BA induced by the uptake of carbon dioxide. Enhanced exposure to carbon dioxide sources has been referred to as accelerated carbonation. Here we report on the successful implementation of the accelerated carbonation of BA in a continuous pilot-scale rotating drum reactor supplied with the exhaust gas of a cogeneration plant. The system was tested in 20 field trials that aimed at stabilizing the ash such as to comply with the regulatory standards for disposal on a lower landfill class or for its geotechnical re-use. Performance and process efficiency were addressed by maximizing the reactor loading and minimizing the BA residence time. While leachates of the fresh BA ash were indicative of a hazardous waste pertaining to a class III landfill, the carbonated material fulfilled the regulatory standards for a class I landfill and, in addition, complied with the standards for geotechnical re-use. In the field trials bottom ash residence times could be cut to 60 minutes thus allowing for an on-line integration of the process.

Session: 18, Room: F, at Thu, 09/05/2019 - 15:15 to 15:30
Oral presentation in Solid waste management