Browsed by
Tag: waste pollution

Singapore’s One and Only Landfill

Singapore’s One and Only Landfill

Comments 0 Comment

Last blog post, we looked at Delhi’s poor waste management system, and saw the health and environmental consequences that came with negligence in building a proper waste disposal facility. Mismanaged landfills are not an uncommon thing in the world, especially in the global south where population and consumption is growing at an exceptional pace, and governments are unable to catch up with the growth. However, there still exist relatively exemplary examples of a good waste management system, which we have right here in Singapore.

Waste management in Singapore today is managed by the National Environmental Agency, and strict laws and waste policies created a comprehensive and efficient waste management system, starting from collection down to disposal in a landfill. Municipal waste from households are efficiently collected through a central refuse chute system in the building. On the streets, dustbins are also a common sight. This, coupled with a hefty littering fine of up to $5000 (EPHA, 2000) ensured that the city’s waste are all collected and accounted for. From here, the solid waste are transported to one of the four waste-to-energy incineration plants in Singapore, where they will be reduced and treated before shipping off to the star of our waste management system, Pulau Semakau.

The Semakau landfill is Singapore’s one and only landfill, located about 8km off the South coast of mainland Singapore. The landfill is a combination of two islands, Pulau Semakau and Pulau Sakeng.

A 7km bund or a barrier is built to enclose a 350 hectare area of seawater, which eventually becomes the landfill. To prevent the leakage of leachate into the surrounding seawater outside of the bund, the inner bund is layered with geofabric and clay to form an impermeable layer (NEA, 2019). Waters surrounding Semakau island is so pristine that the coral nursing facilities have been set up next to it, and the intertidal areas are able to house four endangered plant species (Wild Singapore, 2005). In fact, the waters even housed 2 Neptune’s cup sponges, which were thought to be extinct due to over-harvesting in the late 1900s (NEA, 2015).

Although Semakau landfill is doing an amazing job in keeping Singapore’s waste safely tucked away, we are still faced with the imminent issue of eventually running out of space, estimated to happen in 2035. As such, aside from proper facilities, perhaps the most important factor to a sustainable waste waste management system in a city is eliminating waste and committing to a zero waste future.

References:

Environmental Public Health (Public Cleansing) Regulations—Singapore Statutes Online. Retrieved April 8, 2022, from https://sso.agc.gov.sg/SL/EPHA1987-RG3

NEA. (2015). Phase II Semakau Landfill Ready To Meet Singapore’s Waste Disposal Needs To 2035 And Beyond. https://www.nea.gov.sg/media/news/news/index/phase-ii-semakau-landfill-ready-to-meet-singapore-s-waste-disposal-needs-to-2035-and-beyond

NEA. (2019). Phase I and the Operations of Semakau Landfill. https://www.youtube.com/watch?v=RTQvjTXs0DQ

Wild Singapore. (2005). Semakau Survey 2005. http://www.wildsingapore.com/projects/survey/semakau/results.html

Rubbish “Volcanoes”

Rubbish “Volcanoes”

Comments 0 Comment

Just about a week ago, the city Delhi was engulfed in thick black smoke. The origins of the smoke can be traced back to the Ghazipur landfill, standing at a massive 65 metres tall and spanning across 70 acres wide (The Print, 2020). The landfill is one of the main dumping ground for the populous capital of India, receiving 2,000 tonnes of garbage dumped into it each day.

Fig 1: The massive Ghazipur landfill in Delhi, perpetually smoking as it burns away the methane and carbon dioxide produced (source: Money Sharma/AFP)

Landfill fires are not an uncommon sight in Delhi, where landfills are often haphazardly maintained. In fact, Delhi saw a total of 16 landfill fire in the year of 2021 – more than one per month (Outlook, 2022). Landfill fires worsen the already abysmal health and environmental impacts landfills have on its surroundings. The fires produce acrid smoke that cause initial implications such as coughing and eye irritation, and with prolonged exposure, increase the likelihood of respiratory related illnesses (Swati et al., 2017). The fires also release large volume of methane and carbon dioxide, previously trapped under layers of rubbish. Both are greenhouse gases, with methane being especially potent, having 20 times the greenhouse effect than carbon dioxide (Mohajan, 2012). Fires can also potentially destroy the linings of landfills, causing toxic leachate to leak into the soil and pollute groundwater aquifers, many of which are the main source of water for the residents of Delhi.

So what was the cause of Ghazipur’s landfill fire? For now, the Indian fire department has yet to pinpoint the specific reason, but the fires are most likely triggered by either arson or the immense heat from decomposition of the rubbish. Typical Indian municipal waste contains around 50% bio-degradable organic compounds such as excretion and food waste. When buried under many layers of trash, these organic compounds are left in oxygen deprived anaerobic conditions, perfect for decomposition and generation of landfill gases. Landfill gases contain around 40% of methane and 60% of carbon dioxide. Both gases are extremely flammable, and are responsible for fuelling the perpetual landfill fires (Kashyap et al., 2016).

Moving forward, the Indian government made promises to reduce the height of the le landfill to cut down on the health and environmental issues caused. On another hand, in the recent capitalistic times where even environmental hazards can be transformed into useful resources, researchers have plans on turning the smoking landfill into a natural gas capturing site (Kashyap et al., 2016).

References:

Kashyap, R. K., Chugh, P., & Nandakumar, T. (2016). Opportunities & challenges in capturing landfill gas from an active and un-scientifically managed land fill site – a case study. Procedia Environmental Sciences, 35, 348–367. https://doi.org/10.1016/j.proenv.2016.07.015

Mohajan, H.K. (2012), Dangerous Effects of Methane Gas in Atmosphere, International Journal of Economic and Political Integration, 2(1): 3–10.

Outlook. (2022, March 29). Ghazipur fire blazing on for over 19 hours but landfill fires not new in delhi. Https://Www.Outlookindia.Com/. https://www.outlookindia.com/national/ghazipur-fire-blazing-on-for-over-19-hours-but-landfill-fires-not-new-in-delhi-news-189002

Swati, Ghosh, P., & Thakur, I. S. (2017). An integrated approach to study the risk from landfill soil of Delhi: Chemical analyses, in vitro assays and human risk assessment. Ecotoxicology and Environmental Safety, 143, 120–128. https://doi.org/10.1016/j.ecoenv.2017.05.019

The Print. (2020, December 13). Entire garbage at Ghazipur landfill site will be processed by December 2024, claims Gambhir. ThePrint. https://theprint.in/india/governance/entire-garbage-at-ghazipur-landfill-site-will-be-processed-by-december-2024-claims-gambhir/565985/

Where do I throw this away?

Where do I throw this away?

Comments 0 Comment

Following the trend of rising population and increase in consumption, waste generation has also increased massively around the world. It is predicted that by 2050, worldwide municipal solid waste generation will hit 3.4 billion tonnes, that is 300kg worth of trash per person in a year (Statista, 2018)! With huge volumes of waste being generated yearly, cities are faced with the issue of having enough resources to collect and dispose of the municipal waste generated within its boundaries. To understand more about how cities minimise waste pollution, we take a look at the general process of waste management in a city.

Collection

Fig 1: Waste that is not properly disposed of or collected often make its way to water bodies, following the direction of storm water flow of the city’s drain system (Source: Doug’s Rubbish)

Waste management begins from collection. This means accounting for all trash created within the vicinty of the city. States with a good collection system is more likely to have lower risk of waste pollution, as most of the city’s waste is accounted for and collected to be thrown away at a proper facility. In cities from the global south, where urbanisation and city expansion far exceeds the city’s ability to plan for a comprehensive waste collection system, most municipal waste end up on the streets, and some leak into surrounding rivers or left in a plot of land with no proper facilities. This leads to pollution of the environment, and bring about negative impacts to the people around it, such as contamination of groundwater, as well as exposure to pathogens and diseases originating from the landfill, carried by pests.

Disposal

Fig 2: Untreated municipal waste is choke full of biological waste that harbour disease-causing pathogens, which can spread to humans through pests and contamination of water (Source: wikimedia commons)

Proper collection of waste is not the end of the journey for proper waste management. As previously mentioned, municipal waste is a threat to the environment as well as humans due to the sheer amount of toxic and dangerous substances it harbours. Thus, municipal waste will need to be properly treated before being sent the waste to a proper disposal facility. Incineration is a common method used in most city’s waste management system, whereby the waste is brought to an incineration plant to be combusted. Combustion not only treats the waste, it can also reduce the volume of waste by up to 90% (Demirbas, 2010). Treatment of waste for some cities however, is seen as a form of luxury; not all cities can afford to send their trash in for treatment. When untreated waste enters landfills, it threatens the environment and people near its vicinity. Subsequent blog posts will mention the dangers of poorly managed landfills.

Focus on recycling to reduce waste

As we look through the journey of waste in a city, how it goes from households all the way down to the landfills where they remain for thousands of years, one startling questions comes to mind: What happens if we run out of land for landfills? This concern has haunted cities (especially land scarce ones), and is serious enough to be reflected in one of the 17 Sustainable Development Goals established by the UN (SDG 11) (UN, 2015). Cities must look for ways to encourage the decrease in consumption and increase in recycling, else risk living side by side with the rubbish we produce in the future.

References

Demirbas, A. (2011). Waste management, waste resource facilities and waste conversion processes. Energy Conversion and Management, 52 (2), 1280–1287. https://doi.org/10.1016/j.enconman.2010.09.025

Statista. (2018). Municipal solid waste generation globally 2050 . Statista. https://www.statista.com/statistics/916625/global-generation-of-municipal-solid-waste-forecast/

United Nations. (2015). The 17 Goals | Sustainable Development. https://sdgs.un.org/goals

Skip to toolbar