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Category: Water pollution

The cost of building a city

The cost of building a city

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When talking about urbanisation, the mental image that comes to mind would most likely be forests and greenery being replaced by concrete buildings and asphalt roads. In the midst of creation of such an urban image, the construction industry plays one of the main roles. The construction sector accounts for around 23% of global air pollution, 50% of the climatic change, 40% of drinking water pollution, and 50% of landfill wastes (Go Contractor, 2017). Every aspect of construction poses clear environmental implications. For this blog post, we place focus on the production of concrete, a vital material in building construction.

Cement and concrete

Concrete is produced mainly through the use of three main materials; the aggregate, a binder and water. Aggregates used are usually cheaper options such as gravel or sand, and binders used are cement. Due to its low cost and relatively common material components, basic concrete production utilises Portland cement, created by heating limestone with clay. As Portland concrete is a form of hydraulic cement, it only starts to solidify under the presence of water. As such, concrete can be casted into moulds to form desired shapes by mixing all three components together.

Environmental implications

Fig 1: Quarries become desolate landscapes after it has been depleted of its resources, leaving behind polluted waters that can leach into soil and surrounding aquifers. (Source: Stone World Magazine)

Through the explanation of concrete production, we can identify a few aspects in which concrete production poses environmental or pollution issues. Firstly, the extraction of aggregates and base materials for cement is hugely pollutive. Mining activities are frequently coupled with immense air, land and water pollution. The transportation of the heavy aggregates to and from the mines also contribute significantly to air pollution (Pal & Mandal, 2021). Next, we see that concrete production can be an extremely thirsty activity, requiring large amount of water during its mixing stages. Lastly, we see that cement production is a large source of carbon emissions due to its production requiring large amount of fuel for the heating process. An estimate 8% of human global carbon emissions come from cement production alone (Nature, 2021).

Greener alternatives?

With increasing pressures to cut back on carbon emissions in the recent times, green alternatives have been gaining traction. Green cement refers to any forms of cement with aims of using a carbon-negative manufacturing process. This can be done through the use of recycled cement or concrete, or even this interesting one currently being refined by a group of researchers from the University of Edinburgh, who looks to bypass the intense heating process of cement production through the use of a bacteria and urine. With better technology, we can definitely look forward to a future with greener buildings, both in and out.

References

Concrete needs to lose its colossal carbon footprint. (2021). Nature, 597(7878), 593–594. https://doi.org/10.1038/d41586-021-02612-5

Pal, S., & Mandal, I. (2021). Impacts of stone mining and crushing on environmental health in Dwarka river basin. Geocarto International, 36(4), 392–420. https://doi.org/10.1080/10106049.2019.1597390

Asia’s Dirtiest Holy River – Part 2

Asia’s Dirtiest Holy River – Part 2

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In the previous blog post, we looked at how love and devotion, coupled with improper sewage systems and lax regulations, have led to the demise of the river that courses through the world’s largest ancient city. It was clear that the river Ganges was vital to the people who reside near it, but what exactly have the people done to revive the river?

 

Governmental Action

The Holy City of Varanasi, a popular pilgrimage destination

 

 

The Ganges River provides the state with an array of ecosystem services; it is the source of irrigation water for one of the main exports of India: rice. It also possesses great hydroelectric power, and garners economy through tourism, where the holy city of Varanasi alone saw over 300,000 foreign visitors and 5 million domestic tourists annually.

Evidently, the Ganges is an essential nature resource to the state’s economy, which is why there was an attempt to safeguard this resource with the implementation of the Yamuna Action Plan (YAP). This plan was separated into 3 phases. Phase 1, which took place from 1993-2003, aims to eliminate informal sources of waste disposal into the channel through expanding sewage networks and public infrastructures such as toilets. Phase 1 also planned to educate the public on pollutive behaviours. Unfortunately, due to lack of foresight on a population boom, the new infrastructures built were unable to cater to the new 6.7 million, as it was initially planned to support only 3.5 million people. The second phase involves further capacity building, and the start of water testing to check the progress of the action plan. It was found that after a whole 20 years since the plan ensued, dissolved oxygen concentrations remained low and heavy metal percentages are almost the same pre-YAP, indicating meagre success (Singh and Parmar, 2015).

 

Leaving the river alone

It seems that hard engineering methods implemented by the states saw extremely limited improvements, and that perhaps, should not be the direction to look into for a sustainable restorative strategy. To contain the recent outbreak of COVID-19, the Indian government called for a 60-days lockdown, and industries came to a halt. This was when a miracle happened.

Side by side comparison of the Ganges River before and during the COVID-19 lockdown

 

As seen from the above photos, the Ganges River finally ran clear, no longer plagued with phosphate foams that indicated polluted waters. It seemed unbelievable that with just a short 3-month break from constant consumption of industrial waste, the river was able to restore itself to such a healthy state. For this self-restorative function of the river, we will have to thank the various microorganisms that regulated oxidation and reductions of the fecal materials and several metals in the channel. Waters of the Yamuna River saw revivals of dissolved oxygen levels during the lockdown, indicating life in the river (Mohammad et al., 2020).

 

Moving forward

Alas, when the economy is again allowed to run, and industries begin functioning again, the frothy waters return. However, the sight of pure waters of Mother Ganges runs fresh in people’s mind; perhaps seeing the effects of proper pollution control can motivate a stronger urge in mitigating pollution of the river, and return the Ganges back to its initial purifying state that it is revered for.

 

References

Mohammad, A., Kumar, R., & Parveen, S. (2020). Reduction in Water Pollution in Yamuna River due to lockdown under COVID-19 Pandemic.

Singh, V., & Parmar, S. (2015). Water Quality Parameters of River Yamuna in Delhi After 20 Years of the Yamuna Action Plan. International Journal of Science and Nature, 6.

Asia’s Dirtiest Holy River – Part 1

Asia’s Dirtiest Holy River – Part 1

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Humans love water. Aside from the obvious reasons of needing water to survive, humans have an uncanny attraction to water, evident in the high demand for waterfront apartments, and expensive beach vacations. Our desire to be near a water source dates back to the birth of civilisation, where every cradle formed next to a river.

Pollution of the waters that run through ancient cities

We place focus on the Ganges River for our post today. The Ganges River was where the development of the most extensive Neolithic site, the Indus Valley Civilisation, occurred. Today, it flows through most of India, cutting into Bangladesh and emptying out into the Bay of Bengal. River Ganges provides an array of ecosystem services to the 650 million people within its basin, and is worshipped by the Hindus as the goddess Ganga.

Despite being worshipped for its purifying qualities, the River Ganges is ironically the dirtiest river in Asia, specifically at the stretch called Yamuna River. River health indicators such as low dissolved oxygen content and high heavy metal percentage showed the detrimental conditions of Yamuna. At this stage, the Yamuna is a dead river, incapable of sustaining an ecosystem (Rai, 2011).

Sources of pollutants – household and industrial waste

A woman praying amidst the frothy waters in the Ganges. Frothy waters are the result of high levels of phosphates from pollutants

 

The causes of pollution of River Ganges is overbearingly anthropogenic, and links greatly to the lack of providence of formalised drainage system in the many informal settlements flanking the channel. Faecal matter and household wastewater containing chemicals such as detergents, are often flushed into the channel untreated. Industries such as leather tanneries also illegally release large volume of chemicals and acidic compounds choke full of heavy metals into the sewerage system, which flows into the channel untreated (Parthasarathy, 2016).

 

Sources of pollutants – Religious believes

The process of submerging idols of the goddess Durga into the waters of Ma Ganga

 

Due to its holy status, River Ganges plays a vital role in many aspects of the Hindu religion. During the day of Durga Puja, devotees worships the goddess Durga, and conduct rituals that include submerging idols of the goddess into the holy river. These idols are usually made out of cheap paints laden with heavy metals, and are disposed in the river after the celebrations conclude. It was also believed that after death, if one’s remains are to be cremated at the banks of the Ganges, and ashes scattered into its waters, they will obtain a spiritual level deemed as “Moksha”, liberating them from the endless cycle of rebirth. At the holy city of Varanasi, an estimated 32,000 corpses are cremated and offered into the river annually. The sheer amount of human remains adds on to the pollutants entering the channel.

 

Human attempts to re-purify the waters

The water pollution of Ganges drew attention from many. Environmentalists have called for immediate restrictions on sewage entering the channels, and religious leaders preached about how India is slowly “killing its own mother” (Rowlatt, 2016). In the following post, we will look into the attempts by the state and its people in fighting against the poisoning of Ma Ganga.

 

References

Parthasarathy, S. (2016). In Pictures: The toxic cost of Kanpur’s leather industry. India Today. https://www.indiatoday.in/fyi/story/the-toxic-cost-of-kanpurs-leather-industry-329990-2016-07-19

Rai, R. K. (Ed.). (2011). The Yamuna River Basin: Water Resources and Environment. Springer.

Rowlatt, J. (2016). India’s Dying Mother. BBC. https://www.bbc.co.uk/news/resources/idt-aad46fca-734a-45f9-8721-61404cc12a39

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