Mechanical Biological Treatment Research Articles

MBT Organic Waste Treatment: Lessons Learnt

Treating organic wastes using a combination of mechanical biological treatment (MBT) and anaerobic digestion (AD) is an established process in Europe. In 2010 the UK was considered under resourced with respect to its per capita AD capacity, suggesting a significant prospect for plants in the UK. The ratio of plants then treating municipal solid waste (MSW) compared to biowaste, has changed in the past 10-15 years from favouring biowaste plants to plants treating residual MSW (rMSW). Contractors need to be aware of the parameters that impact on the performance of an MBT AD plant. To identify the key parameters, a review of available information on plant operational performance was undertaken using a wide range of sources. Operational parameters for AD processes are well-documented and provide key process design factors when designing a plant. Consolidation of the information obtained was assessed and a list of problems/solutions compiled that could be reviewed when considering a potential EPC contract. The 2010 list of identified problems has been compared to the current literature discussing the operational performance of MBT AD plants, to see if the issues have been resolved, continue to be a problem, or new issues have arisen.

Anaerobic co-digestion of paper sludge: Feasibility of additional methane generation in mechanical–biological treatment plants

In this work, the feasibility of the anaerobic digestion of paper sludge as a co-substrate in anaerobic digestion mechanical–biological treatment (MBT) plants is investigated. In the first phase, the biochemical properties, biomethane potential (BMP), and pollutant contents of 20 different industrial paper sludges are determined. Following the general evaluation in the BMP tests, the second phase of the project involves the semi-continuous co-digestion of six paper sludges in continuous stirred reactors (CSTR). Paper sludges are categorized according to their origin within the pulp and paper mills: Deinking Sludge (DS), Primary Sludge (PS) and Biological Sludge (BS). The analysis of potentially inhibiting elements shows that the concentrations of chlororganic compounds, mineral oil and some heavy metals are highest in DS, while the mean heavy metal loads in all paper sludges are relatively low compared to other industrial sludges. Large differences in total solids (TS) and volatile solids (VS) contents are observed among the different paper sludges investigated, with DS having the highest TS due to the high inorganic contents. The BMP of the investigated sludges ranges from 90 to 355 NL CH4 kg−1 VS. In subsequent semi-continuous co-digestion experiments simulating MBT conditions, three DS and two fiber sludges (a mixture of PS and BS) show good methane generation rates, while one fiber sludge causes inhibition and indicates an increase in viscosity. In general, co-digestion of paper sludge in anaerobic digestion MBT plants can be a viable option for energy production and also facilitates a safe disposal of the paper sludge digestates.

An Integrated Environmental Assessment of MSW Management in a Large City of a Developing Country: Taking the First Steps Towards a Circular Economy Model

Most of the municipal solid waste (MSW) in developing countries ends up in landfills. For example, more than 95% of the MSW generated in Latin America is disposed of in some type of landfill. Factors such as high organic compositions, low recycling rates and poor control over the disposal sites greatly increase the environmental impacts associated with MSW management in this region, resulting in increased emissions of greenhouse gases (GHGs) and runoff of leachates. Therefore, local governments in Latin America are making efforts to transition to more “circular” management models for MSW. This is the case in the Guadalajara Metropolitan Area (GMA), the third most populous city in Mexico, where the implementation of the following two mechanical biological treatment (MBT) alternatives are being considered: 1) a high-capacity mechanical sorting facility with no biological treatment and 2) a medium-capacity mechanical sorting facility coupled with a composting process. Thus, the aim of the present study was to assess the environmental performance of the current MSW management system (baseline) as compared to the two potential MBT alternatives through life cycle assessment (LCA) and sensitivity analyses. Furthermore, by using a SWOT analysis, this study aimed to provide insights into the main economical, sociocultural, legal, political and technological/infrastructure challenges that need to be overcome in the GMA, as well as other cities in developing countries, in order to transition to circular MSW management models. An assessment of global warming potential (measured in Gg CO2-eq/year) indicated that the current MSW management system (baseline) results in the emission of 111.21 Gg CO2-eq/year, while the two potential alternative scenarios displayed a net emissions reduction of 24 and 34%, respectively, due to material recycling and the substitution of petroleum coke with refuse-derived fuel (RDF) in cement kilns. When evaluating abiotic resource depletion (measured in Gg Sb-eq/year), the potential alternative scenarios both outperformed the baseline with savings increases between 3,380 and 3,501%. This result is largely attributed to the decrease in fossil fuel consumption (due to the substitution of petroleum coke with RDF), which provides a potential reduction of 5.62 Gg Sb-eq/year. The sensitivity analysis revealed that several key parameters, such as the fraction of food and plastic wastes in the MSW, can alter the scenario rankings. Recycling of the recovered materials and treatment of the organic fraction were found to be key strategies for a reduction in direct environmental impacts. Additionally, better management of waste picker activities, standardization of landfill operations and enhancement of material separation and selective collection must be addressed prior to the introduction of new treatment technologies. The results of the study herein can assist in the formation of policies to improve the feasibility of MBT implementation and drive the first steps towards a circular economy model in the GMA, as well as other cities within Latin American and Caribbean regions with similar characteristics.

Eco-Efficiency Analysis of Integrated Waste Management Strategies Based on Gasification and Mechanical Biological Treatment

Integrated solid waste management (ISWM) strategies are developed towards promoting sustainable approaches for handling waste. Recently, gasification and mechanical biological treatment (MBT) technologies were recognized as effective processes for treating municipal solid waste. This study investigates the feasibility of integrating gasification and MBT technologies in multiple ISWM strategies, compared to incineration- and anaerobic digestion (AD)-based strategies. A comprehensive techno-economic and environmental assessment was carried out to evaluate the performance of the examined ISWM strategies. The evaluation was based on the energy generation potential, carbon footprint, and life cycle costing (LCC). An eco-efficiency analysis was conducted to quantify the environmental costs by incorporating the carbon footprint and LCC results. The proposed strategies were applied for the city of Abu Dhabi, United Arab Emirates, based on local bylaws and guidelines. The analysis revealed that the gasification-based strategy had the highest energy production of 47.0 million MWh, followed by the incineration- (34.2 million MWh), AD- (17.2 million MWh), and MBT-based (14.9 million MWh) strategies. Results of the environmental analysis indicated that the MBT- and AD-based strategies contributed the least to global warming with greenhouse gas emissions of 4442 and 4539 GgCO2-eq, respectively, compared to the gasification- (9922 GgCO2-eq) and incineration-based (15,700 GgCO2-eq) strategies. Furthermore, over a 25-year assessment period, the LCC findings demonstrated that the gasification- and MBT-based strategies were the most financially feasible with a positive net present value (NPV) of USD 364 and USD 284 million, respectively. The eco-efficiency analysis indicated that the MBT and gasification strategies are the most sustainable among the examined strategies. The sustainability of the assessed systems was improved by implementing policy and legal reforms, including incentive programs, less stringent bylaws on digestate, and encouraging source separation of wastes. Overall, this research emphasized the potential environmental and financial benefits of incorporating MBT and gasification technologies into ISWM strategies.

Metagenomics analysis of probable transmission of determinants of antibiotic resistance from wastewater to the environment – A case study

During mechanical-biological treatment, wastewater droplets reach the air with bioaerosols and pose a health threat to wastewater treatment plant (WWTP) employees and nearby residents. Microbiological pollutants and antimicrobial resistance determinants are discharged to water bodies with treated wastewater (TWW), which poses a potential global epidemiological risk. In the present study, the taxonomic composition of microorganisms was analyzed, and the resistome profile and mobility of genes were determined by metagenomic next-generation sequencing in samples of untreated wastewater (UWW), wastewater collected from an activated sludge (AS) bioreactor, TWW, river water collected upstream and downstream from the wastewater discharge point, and in upper respiratory tract swabs collected from WWTP employees. Wastewater and the emitted bioaerosols near WWTP's facilities presumably contributed to the transmission of microorganisms, in particular bacteria of the phylum Actinobacteria and the associated antibiotic resistance genes (ARGs) (including ermB, ant(2″)-I, tetM, penA and cfxA2) to the upper respiratory tract of WWTP employees. The discharged wastewater increased the taxonomic diversity of microorganisms and the concentrations of various ARGs (including bacA, emrE, sul1, sul2 and tetQ) in river water. This study fills in the knowledge gap on the health risks faced by WWTP employees. The study has shown that microbiological pollutants and antimicrobial resistance determinants are also in huge quantities discharged to rivers with TWW, posing a potential global epidemiological threat.

Composting of the organic fraction of municipal solid waste as an alternative to the uncontrolled disposal: The case of Kalamata Municipality (Greece)

<p>Kalamata’s decentralized waste management and composting scheme is a successful demonstration of the capacity of a municipality to manage its Municipal Solid Wastes (MSW) by adopting methodologies that can be supported by small scale mobile equipment. According to the revised legislation, Join Ministerial Decision (JMD) 51373/4684/2015, each municipality in Greece should organize a regional decentralized waste management plan to comply with the National and EU Legislation. In Kalamata, a mobile Mechanical Biological Treatment (MBT) unit is in operation which consists of a sorting facility in which recyclable materials are recovered from mixed wastes and a composting facility where the Organic Fraction of Municipal Solid Wastes (OFMSW) is treated into closed aerated windrows. This paper attempts to analyze the characteristics of the applied methodology as well as to set a framework for the optimal treatment of the OFMSW in small decentralised units. Several trials have been performed to optimise the effectiveness of different composting practices for OFMSW. Desirable temperature values for degradation (over 50°C), were achieved during the composting process, while oxygen content was kept between 15-20%. Heavy metals were presented in all the samples analyzed, with concentration levels below the limits set by National Legislation. The values of the physicochemical parameters monitored in this study did not exceed the maximum permissible as well.</p>

The Biological Drying of Municipal Waste in an Industrial Reactor—A Case Study

One of the methods of municipal solid waste (MSW) treatment is biodrying. The literature describes mainly the results obtained in a laboratory- and a pilot-scale reactor. The manuscript presents the results of MSW treatment in a full-scale bio-drying reactor (150 m3). The reactor is operated in one of the Polish installations specializing in mechanical-biological treatment (MBT). During the 14 day period of biodrying in the reactor, the parameters of MSW such as the moisture, temperature, loss on ignition (LOI), and net heating value (NHV) were examined. The temperature of the air in the reactor was also examined. The research also included changes in the above-mentioned parameters of MSW located in three parts of the reactor: the front, middle, and back. The test results showed that the moisture content of the waste decreased from the initial level of 55% to the level of 30%. This was accompanied by an increase in the NHV from 6.3 MJ kg−1 to 9.6 MJ kg−1. At the same time, the LOI decreased from 68% d.m. to 45% d.m. The LOI decrease is not favorable from the point of view of using MSW as refuse-derived fuel (RDF), as was expected in the final usage stage. The results have application value as the plant operator, having at their disposal the controlling of the reactor’s ventilation and the temperature inside the reactor, should select the speed of the moisture removal from MSW at such a level as to minimize the LOI decrease.

Materials and energy recovery at six European MBT plants

Mechanical Biological Treatment (MBT; called “dirty” Materials Recovery Facilities in the U.S.) is a waste management method, developed mostly in Europe, which combines sorting of recyclable materials (metals, paper, plastics, glass) with composting/digestion of green/ food wastes and, in some cases production of a fuel material. In 2018–19, the authors visited six MBT facilities in Europe that use different approaches for the recovery of materials and energy from mixed MSW. These plants were studied with respect to feedstock composition, operating conditions, capital expenditure, financial viability and environmental impacts. The compost product of most facilities examined did not comply with agricultural standards and, therefore, it was classified as compost-like output (CLO) and used as daily cover in landfills. The best composting practice used source separated organic materials (yard and other green wastes) and yielded a marketable compost. MBT plants that did not include the recovery of fuel materials had lower landfill diversion rates and, also, lower capital and operating costs. It was concluded that an MBT plant must include a very efficient sorting and recyclables recovery line and charge a sufficient gate fee. Also, in addition to the recycled products, there should be a stream to recover fuel materials sent to a power plant or cement plant, thus increasing revenue, and landfill diversion, and maximizing greenhouse gas (GHG) savings.

Smart Management Platform for Landfilling of Waste after Mechanical Biological Treatment

With the rapid development of the economy and society, the production of municipal solid waste is continuously increasing worldwide. Therefore, harmless treatments and the disposal of municipal solid waste should be improved. This study combined the concept of Internet of things and smart environment protection with a “cloud, network, end” platform architecture to construct a smart management platform for the planning and management of landfills. The platform was developed for the mechanical biological treatment (MBT) of landfills and was divided into seven modules, landfill design, municipal solid waste production prediction, MBT waste microbial volume reduction, stability analysis, result analysis, remote monitoring, and sharing and communication, which can effectively improve the operation and management of waste, enhance the effective storage volume of a landfill, extend its service life, and thereby improve the sustainable development of the city. This study can be used as a reference for applications in similar projects worldwide.

Sustainability assessment of municipal solid waste separate collection and treatment systems in a large metropolitan area

Among different modes for municipal solid waste separate collection (SC), there is a lack of scientifically based methods for their selection available for decision-makers. This study develops and applies a methodology based on Multi-Criteria Decision Analysis (MCDA) aiming to assess and compare the sustainability of different waste management schemes. Considering the city of Bari (Southern Italy) as a supporting case study, 3 systems/visions of city waste management options are considered: (i) bring points systems with about 35% SC rate (S1, status quo); (ii) door-to-door system with an excellent (>80%) SC rate (S2); (iii) combined bring point and door-to-door system (S3, with about 70% SC rate). Scenarios differed mainly on the management of the residual fraction from SC through mechanical-biological treatment (S1 and S2) or recovery of recyclables at material recovery facility (S3). Sustainability is assessed in environmental, economic, and socio-technical terms by means of MCDA and Life Cycle Assessment (LCA). Results showed that S2 is the best solution in global, environmental, and socio-technical terms, while the weak point is the cost (65.76 € per capita). Even more interesting is the limited deviation between S3 and S2 indicators, amounting to 5.4% and 9.4% in terms of environmental and socio-technical criteria respectively, suggesting a strong competitiveness of the mixed collection mode. Methodologically, the approach proved to be robust and easy to apply by local authority decision-makers.

Comparative evaluation of environmental efficiency of the municipal solid waste treatment scenarios for St. Petersburg region with the life cycle assessment method

The research focuses on complex comparative evaluation of environmental efficiency of Municipal Solid Waste (MSW) treatment scenarios that can be implemented in St. Petersburg and Leningradskaya oblast’. Three scenarios were modelled that technically and economically meet the regional needs. The scenarios imply the following systems: 1) sorting, Mechanical-Biological Treatment (MBT), landfilling; 2) sorting, MBT, Waste-to-Energy (WTE), landfilling; 3) sorting, MBT, Refuse Derived Fuel (RDF) for cement industry, landfilling. In comparison, the “zero” scenario implying landfilling untreated waste was modelled. A Life Cycle Assessment based approach was proposed, which allows comparing scenarios through converting heterogeneous impact categories to a single monetary index. The highest damage reduction (by 60-70% in comparison with the “zero” scenario) was shown in the complex scenarios, including both MBT and energy recovery. 40, 42 and 47% of the total damage in scenarios 1, 2, 3 accordingly is associated with MBT product landfilling. The results show that the main benefit of complex treatment cannot be fully realized without separate collection of food waste. In this situation the most environmentally soundable scenario comprises recyclables separation and subsequent WTE treatment of all the rest with the exception of some non-combustibles.

Composting of fine fraction after mechanical-biological treatment of municipal solid waste

One of most common types of municipal solid waste treatment is mechanical-biological treatment (MBT), which in practice has many variations depending on the method of conducting the technological process and it is possible to get different output fractions. In this paper is analysed waste generated after the MBT with biodrying, where waste after mechanical treatment undergoes process of biodrying, and then is RDF (recovery derived fuel) separated. Fine fraction remains with a high content of organic matter that without additional processing cannot be disposed of on a landfill. The aim of this research was to determine the possibility of fine fraction composting in different conditions – in the open, in the open and covered area, and indoors. In each area are formed three compost piles: 100% fine fraction (KH1, KH4, and KH7), 70% fine fraction and 30% wood chips (KH2, KH5, and KH8), 50% fine fraction and 50% wood chips (KH3, KH6, and KH9). Moisture content, temperature and dissolved organic carbon (DOC) were monitored. Results show that after 13 weeks samples KH1, KH4, and KH7 (100% content of fine fractions) did not achieve DOC value less than 3 000 mg/l. The most effective composting in terms of reducing the DOC is achieved in samples KH3, KH6, KH9. Based on results obtained, it can be concluded that by adding wood chips in fine fraction in ratio 50:50, the most effective and fastest reduction of organic matter is achieved in the analysed samples.

Bioaerosol Emission from Biofilters: Impact of Bed Material Type and Waste Gas Origin

Three semi-technical scale biofilters were applied to treat waste gases at different industrial sites in Poland: a mechanical–biological treatment plant of municipal solid waste, a wastewater treatment plant and a food industry plant. Two types of materials were used as beds in the biofilters: stumpwood chips and pine bark, and stumpwood chips, pine bark and compost from green waste. Both bed materials supported the microbial growth and high numbers (106–108 cfu/g dry mass (DM)) of culturable bacteria, and fungi in beds were observed. There was no correlation between the number of microorganisms (cfu/g DM) and the respiratory activity in the biofilter beds. However, microbial respiration activity corresponded with microbial abundance expressed as microbial equivalents (ME), which was calculated based on adenosine triphosphate (ATP) determination. The biofilters either reduced or increased bioaerosol emissions from industrial plants, depending on the microbial content in the waste gases. A high microbial content in the waste gases made the effect of microbial emission from the biofilter bed negligible. The type of biofilter bed and number of microorganisms in the bed also influenced the final bioaerosol emission, but these factors were relevant for biofilters that treated waste gases with low microbial concentrations.

Environmental and Economic Evaluation of Mechanical Biological Treatment System for Municipal Waste Considering the Political Framework in Ichihara City

Japan’s declining population has caused changes in the amount and characteristics of municipal waste. In order to optimize waste incineration plants as a countermeasure to this problem, we analyzed the performance of the integration of the plants with the Mechanical Biological Treatment (MBT) system. In the integrated system, food waste and sewage sludge from waste incineration plants, sewage treatment plants, and industrial facilities were mixed and fermented to produce methane gas. In this study, we evaluated the environmental and economic performance of the integrated system in four case scenarios. The integrated system is located in Ichihara City in Chiba Prefecture, where the Keiyo Coastal Industrial Zone is located and where petroleum and chemical industries are concentrated. The MBT system in which the heat generated from the incineration of waste was transferred to the Keiyo Coastal Industrial Zone was found to be the best. This method could reduce CO2 emissions by 1341 t-CO2/Y, and the annual cost was the lowest at 1.60 billion yen/Y. However, the results of the sensitivity analysis of the food waste ratio and the piping distance suggested that it may be impossible to obtain appropriate evaluation results without considering the regional characteristics.

The role of energy recovery from wastes in the decarbonization efforts of the EU power sector

Wastes contain large quantities of energy that can be extracted using a variety of methods. European Union has established a waste-to-energy initiative to minimize waste and increase recovery. Τhe EU Landfill Directive promotes more environmental friendly waste management options. Accordingly, EU member states are adopting mechanical-biological treatment processes, bio-methanization and waste-derived fuels. Furthermore, EU is energy-dependent, as its resources are insufficient to meet rising energy demands, and fossil fuels must be imported in large quantities. Wastes are increasingly produced and have a non-negligible lower calorific value that are considered as a power source. Findings highlight the role of waste-to-energy facilities in meeting a portion of the European Union's energy needs and contributing to the achievement of renewable energy targets. The untapped potential, through specific actions, can increase capacity in EU without threatening the goals for recycling. This work presents the current status of energy recovery in EU and investigates the unutilized potential energy recovery from wastes, considering the currently landfilled quantities. The results showed that even in the worst scenario, the energy recovery and the renewable content are too high to be neglected, supporting the decarbonization efforts and enhance circular economy, in line with EU’s Energy Strategy and Paris agreement.

Scenarios of Bioenergy Recovery from Organic Fraction of Residual Municipal Waste in the Marche Region (Italy)

In the Marche Region (Central Italy), the residual municipal waste (RMW) is commonly processed in mechanical biological treatment (MBT) systems. In these systems, following a first mechanical selection, the undersize organic fraction from RMW (us-OFRMW) undergoes a partial aerobic biological treatment before being landfilled as a biostabilised fraction (bios-OFRMW) without dedicated energy or material recovery. Alternative us-OFRMW management scenarios have been elaborated for this region, at both present (reference year 2019) and future (reference year 2035) time bases. In the first scenario, the potential bioenergy recovery through anaerobic digestion (AD) from the us-OFRMW was evaluated. The second scenario aimed at evaluating the residual methane generation expected from the bios-OFRMW once landfilled, thus contributing also to the potential environmental impact connected with landfill gas (LFG) diffuse emissions from the regional landfills. The diversion to AD, at the present time, would allow a potential bioenergy recovery from the us-OFRMW equal to 4.35 MWel, while the alternative scenario involves greenhouse gas (GHG) emissions equal to 195 kg CO2 eq. per ton of deposited bios-OFRMW. In the future, the decreased amount of the us-OFRMW addressed to AD would still contribute with a potential bioenergy recovery of 3.47 MWel.

Microbiota Dynamics of Mechanically Separated Organic Fraction of Municipal Solid Waste during Composting.

Mechanical-biological treatment of municipal solid waste (MSW) facilitates reducing the landfill workload. The current research aimed to study general activity parameters, content, functions, and diversity of fungal and prokaryotic microbiota in mechanically separated organic fraction of MSW (ms-OFMSW) composting, without using bulking agents and process-promoting additives. During 35 days of composting, vigorous emission of CO2 (max. 129.4 mg CO2 kg−1 h−1), NH3 (max. 0.245 mg NH3 kg−1 h−1), and heat release (max. 4.28 kJ kg−1 h−1) occurred, indicating intense microbial activity. Immediately following the preparation of the composting mixture, eight genera of lactic acid bacteria and fungal genera Rhizopus, Aspergillus, Penicillium, Agaricus, and Candida were predominant. When the temperature increased to more than 60 °C, the microbial biodiversity decreased. Due to succession, the main decomposers of ms-OFMSW changed. The Bacillaceae family, the genera Planifilum, Thermobifida, and Streptomyces, and the fungal genera Thermomyces and Microascus were involved in the processes of organic matter mineralization at the high-temperature and later stages. The biodiversity of the microbiota increased at the stages of cooling and maturation under conditions of relatively high nitrogen content. Thus, the microbial community and its succession during ms-OFMSW composting were characterized for the first time in this work.

Volatile Fatty Acid Production from Food Waste Leachate Using Enriched Bacterial Culture and Soil Bacteria as Co-Digester

The production of volatile fatty acids (VFAs) from waste stream has been recently getting attention as a cost-effective and environmentally friendly approach in mechanical–biological treatment plants. This is the first study to explore the use of a functional bacterium, AM5 isolated from forest soil, which is capable of enhancing the production of VFAs in the presence of soil bacteria as a co-digester in non-strict anaerobic fermentation processes of food waste leachates. Batch laboratory-scale trials were conducted under thermophilic conditions at 55 °C and different pH values ranging from approximately 5 to 11, as well as under uncontrolled pH for 15 days. Total solid content (TS) and volatile solid content (VS) were observed with 58.42% and 65.17% removal, respectively. An effluent with a VFA concentration of up to 33,849 mg/L (2365.57 mg/g VS; 2244.45 mg/g chemical oxygen demand (COD)-VFA VS; 1249 mg/g VSremoved) was obtained at pH 10.5 on the second day of the batch culture. The pH resulted in a significant effect on VFA concentration and composition at various values. Additionally, all types of VFAs were produced under pH no-adjustment (approximately 5) and at pH 10.5. This research might lead to interesting questions and ideas for further studies on the complex metabolic pathways of microbial communities in the mixture of a soil solution and food waste leachate.

Exploring the Potential in LID Technologies for Remediating Heavy Metals in Carwash Wastewater

Carwash wastewater (CWW) can be a significant source of environmental pollution due to the diversity and high concentrations of contaminants it contains. This toxic wastewater can contain several different heavy metals that if left untreated, can enter surface and sub-surface waters. Innovative, nature-based solutions such as low-impact development (LID) technologies may provide an eco-friendly CWW treatment process that is both effective and affordable. This research reviews the available literature to provide definitive values of flowrate and contaminant concentrations found in CWW around the globe. Dividing LID technologies into two groups, vegetated and unvegetated systems, the authors explored the literature for the general performance of these technologies to sustainably treat heavy metals in CWW. Depending on the car wash’s size and intended purpose, whether cleaning vehicles in agriculture-based rural communities, mining, or in high-density urban environments, volumetric flowrates requiring treatment found in six different countries ranged from 35–400 L/car. CWW also contains a wide range of contaminants at various levels, including COD, turbidity, TDS and TSS, surfactants, oils and greases, and heavy metals such as lead, cadmium, zinc, copper, chromium, and iron. Heavy metal removal by both vegetated and unvegetated LIDs shows mixed results in the literature, but given the different processes involved in both types, the authors propose a system that combines these types in order to provide all the necessary removal processes, including mechanical filtration, adsorption, sedimentation, chemical and biological treatment processes.

Quantification of climate change mitigation potential at Novi Sad landfill

Unsanitary landfills and inadequate waste management system represent the 3rd largest global anthropogenic source of methane emissions in the environment. Waste management system in Novi Sad, the second largest city in Serbia, significantly contributes to the national carbon footprint. Unsanitary Municipal solid waste landfill in Novi Sad receives and deposits mixed waste without any treatment, thus causing the organic waste to biodegrade within the landfill body, and produce and emit the landfill gas (mostly CH4 and CO2) in the environment. Other potential sources of greenhouse gas emissions from waste management system include vehicles used for waste collection, machinery used at the landfill and landfill fires. The purpose of this study is to determine total baseline emissions of relevant greenhouse gases from the waste management system in Novi Sad, and to estimate and quantify the emission reduction potential for defined organic waste treatment scenario. The potential scenarios for organic waste diversion and treatment from the landfill include composting, anaerobic digestion, mechanical biological treatment, waste to energy, etc. Quantification of baseline emissions and climate change mitigation potential are estimated using the Solid Waste Emissions Estimation Tool, the model developed by Climate and Clean Air Coalition.