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His cutting and pasting is as creative as the new cookie-cutter style of construction and his poster crowds as fast as the Valley.[break]
But compact, high-rise urban living –coupled with high adoption of public transportation – can result in lower per capita carbon emissions than suburban sprawl, according to David Owen, author of the book, Green Metropolis: Why Living Smaller, Living Closer, and Driving Less are the Keys to Sustainability.
And to add to the goodwill for vertical growth, the emerging towers in Bal Kumari may soon have some of the lowest per capita wastewater emissions in Kathmandu, even when filled with residents.
Astra Development Network is designing an “ecologically friendly” housing community in Bal Kumari for Westar Properties.
The development will house 215 apartments in four towers and will include a decentralized wastewater treatment system (DEWATS), as well as rainwater harvesting, groundwater recharge, and solar electrification of its common areas.
“If a colony decides to treat its waste, this benefits the whole community and relieves a social burden from the developers,” says Sangeeta Singh, director of Astra Development Network.
Greywater, or domestic wastewater collected from sinks, showers and laundry that does not contain fecal matter and urine, will be treated in a constructed wetland – an artificially created habitat for natural filtration of effluents.
The treated greywater will then be reused for gardening or pumped back into building blocks for use in toilet flushing.
Given previous experience with operation and maintenance of constructed wetlands and the amount of space these require, planners are considering combining natural treatment with some form of mechanical pre-treatment.
The separate piping network for recycled water has already been incorporated into construction.
“Ethically, this has to be done,” says Sangeeta Singh, who is also Professor of Urban Planning at Kathmandu Engineering Institute. “We’re teaching our students that wastewater should only be thrown away after treatment. If we ourselves aren’ doing it, then it doesn’t make sense.”
Singh argues that decentralized treatment is the best option for housing colonies built along the peri-urban fringe. But in the case of blackwater, or wastewater containing human toilet waste, where reuse options are currently unviable, investment in treatment will depend less on ethics.
Blackwater will be settled in septic tanks – a legislative requirement, compliance of which is in itself not the norm in Kathmandu – but possibly without further treatment.
“The problem is that when we treat the water and let it pass to the sewage system, it’s mixed with a sewerage network that’s already contaminated. We want to treat the blackwater somehow, provided that the sewerage system isn’t polluted.”
She suggests the government either partner with or establish regulations for private developers to treat their wastewater to a degree.
But Rajesh Shrestha, Director of The Comfort Housing does not see grounds for this. “Not even one percent of the city’s population lives in planned settlements, so this is negligible. How can the government save the environment by focusing on this section of the population? It has to take care of the major portion living in sprawled settlements.”
Furthermore, with most housing colonies hardly occupied, it will be a while before septic tanks fill.
For now, there are no government incentives to install DEWATS, and nor are customers demanding it.
“It’s not that our sustainable services add value with regards to getting our apartments sold,” says Singh. “The customer is satisfied as long as there’s sufficient water, as long as their sewage is unclogged and as long as they get quality services.”
Shrestha agrees. “If you see the customer, they are least bothered by the environment. They just want economic value.”
That housing colonies are investing in DEWATS, despite popular indifference and lack of government support, is commendable. But the success of these systems in reducing wastewater emissions to the riparian environment will depend on the post-construction phase.
Many constructed wetlands have suffered operational and maintenance problems due to design faults or lack of long-term oversight.
For example, Astra Development Network constructed 21 rows of housing units in Kusunthi in 2003 that included a constructed wetland for all the wastewater – grey and black – to filter through a bed of reeds before discharging into the river.
Eventually, the system clogged and it continues to suffer from weak management.
In contradiction to Hutta Ram Vaidya’s expose on irresponsible development, some high-rises may become benchmarks for responsible construction and, if people choose to live in them, responsible living.
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