Climate impact of an optimised gas treatment on old landfills

It is a well-established fact that the quality and quantity of landfill gas (LFG) start declining after a landfill is closed to further waste intake. Conventional gas treatment and utilisation systems such as flares and gas-driven engines require a certain quality of LFG: specifically, a sufficient methane concentration. Various measures are utilised to maintain the necessary quality of LFG, including a turn-down of gas extraction rates and a shutdown of low-quality gas wells, resulting in a decline of LFG production. This, however, does not have to be the case. The low calorific value (LCV) LFG capture and treatment technology developed by e-flox and referred to in this article as ‘LCV LFG System’ can significantly increase the collection rate and the amount of treated methane in an old landfill. This article introduces such new treatment measures, describes gas capture calculation methodologies and presents actual results based on a medium-sized landfill in Germany. The study demonstrates, among other things, that the LCV LFG system can reduce the CO2 avoidance costs to roughly 10 €/tCO2eq. We present this new technology as a quick and straightforward measure of dealing with the climate issues related to methane emissions of old landfills.

Energy recovery from municipal solid waste landfill for a sustainable circular economy in Danang City, Vietnam

Sustainable development of Danang City in the direction of circular economy (CE) and a zero-waste city is an urgent solution because the impacts of local municipal solid waste (MSW) generation in the city’s districts are increasingly causing serious pressure for MSW management and treatment. Segregation of waste at source, reuse, recycling, and energy recovery from landfill gas (LFG) generated is considered as one of the keys to solving the dilemma of sustainable waste management. This study analyzed and evaluated the generation of greenhouse gases (GHGs), mainly CH4 and CO2 gases from the Khanh Son landfill based on the application of the EnLandFill software and assessed the potential of energy recovery, clean electricity generation, as well as GHG emission reduction in the period of 2021 – 2050 based on the CE-oriented scenario of the city government. With the potential to recover LFGs in the period of 2021 – 2050 could reach 136.9 million m3 (with efficiency E = 90%), the total annual potential value of electricity generation is estimated at 420.767 million kWh, equivalent to the total potential for GHGs emission reduction (GWP) about 271.25 thousand tCO2-eq. At the same time, this will be a baseline study to serve as the basis for extensive assessments and to suggest the most appropriate waste management strategies and policies create a circular economy in the future.

The Scope and Potential for Mini-Grid Power Systems Based on Biomass Waste for Remote Areas in Sub-Saharan Africa

Sub-Saharan Africa (SSA) has been experiencing an energy crisis. Socio-economic balances depend on access to clean, convenient, and dependable energy. This is critical for remote areas which are off the national grid, necessitating the installation of renewable energy sources such as bioenergy plants. These plants could valorize waste using combustion and gasification or biogas plants. The challenge is to produce a competitive levelized cost of electricity (LCOE). Nations like Germany and Sweden have successfully launched these. SSA can benchmark from these and valorize its biomass wastes. Key issues to consider would be cost-effective supply chains, sustainable harvest rates, after sales support, and good regulatory frameworks. This study was mostly a desktop review with a few field study observations. It was concluded that the stoker fired boiler and landfill gas ‘biomass only' technologies would have the least capital costs, although gasification and anaerobic digestion are also competitive in terms of LCOE.

Sustainability Challenges of The Landfill Gas Power Plants in Indonesia

As part of urbanization, waste causes a significant challenge in Indonesia. As part of the solution to this challenge is applying the landfill gas (LFG) powerplant. Various efforts are being conducted to implement the LFG powerplant in Indonesia. The literature review was conducted to focusing on the performance sustainability of the LFG powerplant. The explaining power capacity, expected energy supply, actual energy supply, problems, and their cause and impact data are presented. All LFG power plants show technical problems, such as leakage gas pipe, defected gas capture, absence of gas storage and purification equipment, and limited monitoring system. Financial and social challenges exacerbate the technical issues that risk the system’s sustainability, such as unclear funding mechanism, lack of capacity from stakeholders, and conflict with the local community. All of the issues hindered achieving performance targets in the powerplant development, operation, and maintenance phase.

Geographic Information Systems based approach for assessing the locational feasibility for biomethane production from landfill gas and injection in pipelines in Brazil

ABSTRACT Biomethane can readily replace fossil fuels including natural gas, which has similar physical and chemical properties. In Brazil, municipal solid waste is predominantly disposed of in landfills. Landfill gas is mostly employed for electricity generation, but still at low levels when compared to the existing potential. Production of biomethane from landfill gas may be an alternative to exploit the existing potential, but Brazil’s pipeline network is rather limited and concentrated along the country’s coast. In this context, the research sought to identify the locational viability of using landfill gas to produce biomethane and injecting it into pipelines, considering the available potential and its proximity to Brazil’s existing pipeline network. The QGis software was used to integrate the information. Territorial arrangements with a biomethane production capacity of more than 15,000 Nm3 day−1 and located up to 50 km from the pipeline network were considered feasible. The research estimated a potential production equivalent to 3,407,027 Nm3 day−1 of biomethane from landfills in Brazil. This potential corresponds to 6% of country’s natural gas consumption in 2019 and is almost 32 times greater than current production of biomethane from all substrates used with this purpose in that year. The results indicate the suitability of using geographic information systems to identify regions that can benefit from the production of biomethane from landfill gas using the existing natural gas pipelines as an alternative to the electricity generation and provides relevant subsidies to the formulation of more efficient public policies in both the sanitation and energy sectors.

Influence of the Heat Loss on the Performance of a Two-stage Gasification Reactor

This paper investigates the gasification efficiency of a two stage gasifier, described in all detail in previous works, as a function of the heat loss across the reactor walls. The behaviour of the reactor was simulated using a simple mathematical model already reported in previous papers. The examined heat loss ranges from 0% of the heat produced by the exothermic reactions into the reactor, up to 20%. Calculations have been performed by keeping constant both the injected total oxygen and its partition between the two stages, while different feedstocks have been used, such as landfill gas, municipal solid waste (MWS), willow and rice straw. The results of calculation show that the gasification efficiency at fixed oxygen injection is greatly influenced by the feedstock. The elaboration of the obtained data indicates also that the trend of the gasification efficiency vs. heat loss is a function of the high heating value of the feedstock and of the ratio between the oxygen present into the reactor (injected + the one of the feedstock) and the stoichiometric oxygen necessary to transform the feeding into carbon dioxide and steam.