“As an architect, you design for the present, with an awareness of the past, for a future which is essentially unknown.”

A quote by Ar. Frank Gehry, which holds true, in current times more than ever. With the ongoing climate change and climate crisis, architects face the challenge of designing and executing architecture that will achieve maximum sustainability, for present and future generations. Sustainable architecture is the current necessity and fortunately, its trending awareness is beneficial for the environment.

Sustainable architecture includes design and building techniques, which avoids or minimizes the negative effect that the building industry has on the environment.

Wastewater management in Sustainable Architecture
This futuristic vertical factory feeds off a city’s waste to produce energy ©www.inhabitat.com

Wastewater management-

Wastewater is the impure water which is used by the inhabitants for different daily purposes and is directly or indirectly released into a water body. This water contains impurities which can be in the form of solid, liquid, gas, or all of the mentioned states.

The process of purification of these impurities is known as Wastewater management. It is one of the most significant processes concerning sustainable architecture.

Water scarcity is one of the major aspects of the climate crisis, the ever-elevating population and its increasing demand for water resources, has made it a necessity to recycle and reuse the water, to meet the demands. Architecture and the building sector is one of the largest users of water, right from the primary stage of construction to usage of the inhabitants, the building sector consumes a tons of water. A need for better conservation of water is felt, wastewater management comes into the picture in this scenario.

Reusing and recycling of wastewater are not only beneficial for conserving water, but it also has its own advantages. For example, the agriculture sector is the major consumer of water. The reused water is considered to be beneficial for irrigation purposes and it ensures the nutrients necessary for the crops.

Recycled water can be used again for washing and gardening purposes, making it a sustainable choice.

Wastewater can be categorized into two types-

1. Domestic wastewater:

The sewage water collected from residential and commercial complexes through municipal lines falls under this category.It comprises 99% water and 1% organic or inorganic microorganism.

This is further classified into –

Blackwater: Latrine related wastewater.

Greywater: Non-latrine wastewater from kitchen sinks, dishwasher

2. Industrial wastewater:

Water released from industries, which has a high quantity of chemical compounds mixed with water.

It is considered more harmful than domestic wastewater. Wastewater management is a large-scale process and hence it’s categorized into two types according to the nature of the water to be treated, area availability, and municipality norms.

  • Centralized process

In this process, water from different sites and buildings is collected at one central point and is treated at one single treatment plant. This is possible only if the area for such a large-scale water treatment plant is available.

  • Decentralized process

As opposed to the centralized process, the decentralized process includes the treatment of water on site. These systems have their own advantages and disadvantages. A centralized system may sound beneficial, but consumes a lot for energy, and is not advisable especially for smaller municipalities. Decentralized systems are on a small scale and hence consume less energy and can be made available in the smallest of municipalities.

A few sustainable methods of Wastewater management are listed below.

Wetland treatment:

Wetlands or lagoon is a water body or a pond, which purifies water through stabilization methods. Water plants and fungi like hyacinth and algae, plankton, and certain bacteria help to purify water once it stabilizes. It’s a mechanized process but requires very little energy. It can recycle the total amount of water that was supposed to be treated. Although, it requires a large piece of land and a suitable climate.

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Aerated lagoons or wetlands. ©www.extensionpublication.unl.edu.jpg
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Aerated lagoons or wetlands. ©www.Snyder&associates.com.jpg

Aerobic and anaerobic digesters:

Aerobic and anaerobic reactions are systems in which microorganisms are used to decompose the contaminants from the wastewater. The aerobic system requires the presence of oxygen during the whole process. This calls for a mechanized induction of oxygen in biomass. This results in the consumption of energy. Hence, this type of digester is considered not so energy efficient in comparison with its counterpart digester. Anaerobic digesters use the mechanism where the wastewater and biomass are not supposed to be exposed to oxygen or air. Hence, the wastewater treatment plant should be made airtight and does not require a high energy-consuming mechanism. One can infer that anaerobic digester can be a comparatively more sustainable alternative than the aerobic digester.

Soil aquifer treatment

In this system, wastewater is percolated into groundwater using a mechanical process. The soil acts as a sieve, filtering all the contaminants from the wastewater and the purified water is allowed to mix with groundwater to reuse it shortly. One of the major advantages of this treatment is the addition to the quantity of groundwater and the increase in groundwater reserve. This may result in a change in the hydrological properties of groundwater, which might not be good for the environment.

These methods come under conventional sustainable wastewater treatment processes. One of the contemporary yet sustainable processes developed is the Nerada wastewater treatment process.The award-winning technology was invented in the Delft University of Technology by Prof Mark van Loosdrecht, Netherlands. It is developed by the University and Dutch Foundation for Applied Water Research. This technology uses aerobic granules (which functions equivalent to the bacteria in conventional aerobic digesters) sludge. These granules perform all the biological processes, simultaneously, hence giving fast results.

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Sweden’s first Nereda wastewater treatment plant ©www.dutchwatersector.com.jpg
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Aerial View of Sweden’s first Nereda wastewater treatment plant. ©www.dutchwatersector.com

They function as fast settling agents as opposed to the conventional methods where more time is required for the settling process. In this process the waste or effluent is pushed outside the biomass, thereby reducing the energy and cost for the process required. As the processes of aeration, sedimentation, and settling happen simultaneously, there are no separate units installed for these processes. Everything is carried around in a single unit. This makes it cost-effective. It consumes 50% less energy than the other methods. The equipment that is used for this process is small and easy to use in comparison to other methods. Hence, this can be installed in small municipalities and developing and underdeveloped countries as well. This method is the ideal sustainable alternative for a centralized wastewater treatment plant.

Nereda wastewater treatment - Sheet3
Nereda wastewater treatment technique. ©www.wateronline.com

One of the examples of implementation of this technique is the metropolis of Rio-de-Janeiro, Brazil. Rio-de-Janeiro was hosting the Olympics in 2016. but Wastewater management was a major issue hovering over the city. Rio solved its wastewater treatment issue by introducing the Nerada wastewater treatment plant, in 2012. Located in Deodoro, it was built for approximately 480,000 end users.

In conclusion a sustainable approach towards wastewater management ensures the well-being of the residents and allows the resources to be used up to their optimum limit. Wastewater management helps in creating a circular economy for the cities as every commodity is used consciously. A sustainable approach towards Wastewater management is a boon towards a green and clean future.

Samruddhi Kulkarni
Author

A firm believer of J.K Rowling’s famous quote, “Words are, in my not so humble opinion, the most inexhaustible source of magic”. Samruddhi Kulkarni is a 23 year old architect, an ardent reader, coffee enthusiast, loves to explore places and preserve them in her diary.

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