[COLUMNIST] Waste-to-Energy: Is there a better alternative to Incineration?

MALAYSIA still heavily relies on landfilling as its primary waste disposal method, posing ongoing challenges in waste management. A 2023 report shows Malaysia sends 38,000 metric tonnes of solid waste daily to over 100 landfills, expected to run out of space by 2050. Thus, it is imperative for us to implement effective waste management to avoid a future without space for trash disposal.

Waste-to-energy (WTE) is the process of generating energy, such as electricity and heat, from waste, typically through incineration — burning waste at high temperatures. This method is common in countries where the land itself is a scarce resource not to be used for landfilling waste.

In Europe, incineration has become the primary method for waste disposal upon banning of landfilling untreated waste. The European Union has even classified incinerators as a form of renewable energy,

Malaysia is also eyeing the opportunity to transform waste into useful resources while reducing the reliance on less sustainable landfilling. Despite government proposals (from then and now) to build WTE plants like incinerators, plans have faced resistance from the public, including the most recent proposal for an incinerator in Rawang.

Rawang residents united as the Rawang Tolak Incinerator Network (RTI), expressing their opposition to the Selangor state government’s proposal for an incinerator in their area, citing potential health and environmental impact as their main concern.

Their concern is valid because waste incineration generates flue gas, which, if untreated or unclean, contains harmful pollutants such as heavy metals, dioxins, and sulfur dioxide.

Indeed, Tait et al. (2020), for example, found a significant association between waste incineration and various adverse health effects, including neoplasia, congenital anomalies, miscarriage, and infant mortality.

Another meta-analytical review of studies spanning from 2005 to 2020 stated that while the results were mixed or limited, the most consistent evidence was the adverse birth and neonatal outcomes, while there was also some evidence of other increased health risks associated with living near landfills, incinerators, or dumpsite or open burning sites (Vinti et al., 2021).

However, both studies have also stated that the different generations of incinerator technology might also have a part to play. Tait et al. (2020) mentioned that the older generation of incinerator technology and infrequent maintenance are strongly linked to adverse health effects. Vinti et al. (2021) have specified that most landfills and incinerators investigated were of the older generation while simultaneously underscoring that the evidence was inadequate to establish a strong relationship between a specific outcome and exposure.

Relatedly, Tom Cole-Hunter et al. (2020) asserted that despite limited evidence, appropriately designed and managed state-of-the-art WTE incinerators pose relatively lower health risks compared to landfilling and other waste management methods.

Despite the mixed results regarding the link between human health and living near incinerators, such risk needs to be considered, and further study is required. Tait et al. (2020) warned that although there are suggestions that newer incinerators with robust maintenance schedules may be less harmful, adverse health effects from exposure often take many years of cumulative exposure to develop.

Otherwise, in terms of energy production, an incinerator plant is undoubtedly one of the best WTE methods. As Tan et al. (2014) stated, incineration presents the highest potential heat and electricity production potential among the three technologies examined, including anaerobic digestion and landfill gas recovery system. With 1,000 tonnes of waste per day, incinerators can produce 1,430MWh of heat and 480MWh of electricity per day. However, this does not mean that we should turn a blind eye to other technologies, such as anaerobic digestion and plasma gasification.

Alternative way forward

Yong et al. (2019) evaluated different WTE technologies, including incineration, anaerobic digestion, gasification, and landfill gas recovery, in terms of their energy production, capital and operational cost, and greenhouse gas mitigation capability. The researchers found anaerobic digestion to be the optimal WTE method for organic-rich waste like food waste, converting it efficiently into bio-fertiliser and biogas with little to no hazardous by-products compared to incineration.

In fact, Malaysia’s first anaerobic digestion plant, Pusat Anaerobic Digestor MPAJ in Ampang Jaya, has been operational since July 2022. By December 2022, it had processed over 35,000kg of food waste into 19,120L of liquid compost, a form of fertilizer.

In addition to the valuable compost, which is currently in high demand due to fertilisers shortage, anaerobic digestion produces biogas. This biogas can be used for electricity generation or as fuel for natural gas vehicles.

While the benefits of producing useful compost and biogas with minimal harmful by-products are evident, there are certainly some challenges and issues to consider.

A critical review by Piadeh et al. (2024) identified increased vehicular movement, odours, high water demand in certain seasons, and potential environmental problems from operational failures as key issues associated with anaerobic digestion plants.

However, with appropriate measures, anaerobic digestion does stand out as one of the most effective ways for organic waste treatment, offering significant benefits to communities.

Another WTE technology that should be considered is plasma gasification. Yong et al. (2019) proposed plasma gasification as the most sustainable WTE solution for treating inorganic waste like glass, metal, and plastic.

Plasma gasification and incineration are both thermal waste treatment methods involving high temperatures. However, plasma gasification is deemed safer than incineration because it operates under low oxygen conditions, minimising oxide formation.

Gandhi (2015) conducted a comparative study on pollutant emissions from gasification, incineration, and landfill methods in the form of nitric oxide, sulfur dioxides and particulate matter. The study highlights gasification’s dramatic improvement in environmental impact and energy performance. Plasma gasification, in particular, demonstrates significantly lower levels of nitric oxide and sulfur dioxide emissions compared to incineration and landfill methods, albeit with slightly higher particulate matter emissions than landfills.

A more recent study by Ramos, Teixeira and Rouba (2019) echoes these findings, stating that two-stage plasma gasification is a significantly more sustainable alternative to conventional incineration. They also note that electricity production from plasma gasification is 2.7-fold higher than from incineration.

Plasma gasification not only generates more electricity with a lesser negative impact on the environment but the slag produced by plasma gasification is also considered completely safe and has the potential to be used in construction materials.

In addressing waste issues, WTE is not the only way forward; zero waste or waste minimisation is also a viable strategy. While WTE or other waste management methods focus on dealing with already-produced waste, waste minimisation aims to reduce landfill or incinerator-bound waste.

While waste minimisation encompasses various actions from different groups, it can be simplified down to the well-known 3Rs: Reduce, reuse, and recycle.

In the past, Malaysia has made a significant push to promote waste recycling. In 2016, the country began enforcing a waste segregation programme, mandating the separation of waste into paper, plastic, and other categories.

Since the enforcement of the waste segregation programme, Malaysia’s recycling rate has been steadily increasing. According to the report, the national recycling rate from 15.7% in 2015 to 35.38% in 2023, just shy of our targeted 40% in 2025.

With more encouragement for recycling, we are confident in reaching the target by 2025.

With the current heightened focus on Sustainable Development Goals (SDGs) and Environmental-Social-Governance (ESG) criteria, WTE certainly stands out as an area that deserves more scrupulous attention. This is because waste management is closely aligned with several Sustainable Development Goals (SDGs), but it is primarily associated with SDG 12: "Responsible Consumption and Production." Within SDG 12, Target 12.5 specifically addresses waste management, calling for the reduction of waste generation through prevention, reduction, recycling, and reuse. Additionally, waste management contributes to other SDGs such as SDG 11 (Sustainable Cities and Communities), SDG 6 (Clean Water and Sanitation), and SDG 13 (Climate Action), among others, due to its broader environmental, social, and economic implications.

Furthermore, for Malaysia, reaching maximum landfill capacity necessitates immediate attention. Coupled with Malaysia's pledge to achieve net-zero greenhouse gas emissions by 2050, it is understandable that incineration emerges as an appealing option.

However, as data and science suggest, anaerobic digestion and plasma gasification can offer more benefits in a much more sustainable fashion and should be pursued as our primary options for WTE technology.

Simultaneously, our efforts to encourage recycling to minimise waste production must continue unabated. Promoting reuse, reduction and recycling will significantly decelerate the rate at which landfills fill up.

Employing the right method and technology can help tremendously in Malaysia’s sustainability and ensure our future is cleaner, greener, and healthier.

---

Chia Chu Hung is a Research Assistant at EMIR Research, an independent think tank focused on strategic policy recommendations based on rigorous research.