Troubled by water shortage? Rules approved for converting sewage waste to drinking water
Business
It is said that recycling sewage is more environmentally friendly when compared with desalination
LAHORE/LOS ANGELES (Web Desk/Reuters) – Water scarcity is surely an issue. In fact, very serious issue. Many in Pakistan don’t have access to clean drinking water, resulting in diseases amid lack of health services and also producing extra costs for not only the affected families while taxing the healthcare system.
Even when water supply is available, the erosion and other issues related to pipelines mean its quality isn’t ensured and carries materials that are injurious to human health.
At the same time, we are consuming underground water at a rate where the amount consumed isn’t replenished through natural means like rains. So the quality of our underground water is on a rapid decline.
Water desalination is one of the available remedies through which the seawater can be utilised for human consumption. But this solution is applicable to the cities located along the Arabian Sea coast.
With global warming or climate change already visible around us with rising temperatures and less rains along reduced water flow in rivers, we in Pakistan seriously need to how to tackle this merging challenge.
Read more: Climate change means poverty for many. Is Pakistan ready to address the challenge?
Meanwhile, some people around the world have been thinking in terms of out-of-the-box ideas such as converting the sewage waste into pure drinking water. Yes! You heard it right.
You may want to vomit, but the fact remains it will soon become a reality, as Reuters reported that the regulators in California – the US state located on the west coast – earlier this week cleared the way for widespread use of advanced filtration and treatment facilities designed to convert sewage waste into pure drinking water that can be pumped directly into systems feeding millions of household taps.
Proven technologies capable of recycling wastewater for human consumption, a concept once derided by critics as "toilet to tap," have gained greater credence in recent years as water-conscious California faces worsening drought cycles from climate change.
More than a decade in the making, the regulations adopted by the State Water Resources Control Board represent a landmark in the quest to reclaim some of the hundreds of millions of gallons of waste discharge that flows out to sea unused each year, supporters say.
"Today heralds a new era of water reuse," Patricia Sinicropi, executive director of the recycling trade group WateReuse California, said in a statement.
A number of communities have for years been blending highly purified wastewater into aquifers and reservoirs before people can drink it, a practice known in the parlance of engineers and resource managers as "indirect potable reuse."
In the sprawling Orange County suburbs south of Los Angeles, home to Disneyland and upscale beach towns, much of the drinking supply for 2.5 million people comes from highly distilled waste that is used to recharge the groundwater basin and eventually is drawn back to the surface.
DIRECT VS INDIRECT
The 69-page document approved on Tuesday provides a legal and regulatory framework for "direct potable reuse," allowing the end-product of advanced purification to be fed straight into drinking water systems, without first making a stop in some kind of environmental buffer.
The foundation of the technology, used for more than a decade in Orange County, puts pre-treated waste discharge through intense microfiltration, reverse osmosis and disinfection by ultraviolet light and hydrogen peroxide.
The new regulations mandate an additional ozone disinfectant process and biological carbon filtration. Greater pathogen removal and stricter monitoring is also required.
In some cases, the water would be routed to a conventional drinking water treatment plant before it is piped to households. In others it could go directly to the tap.
The cost is high. Investments in such facilities are expected to run at least $1 billion, limiting them to large, well-funded water supply utilities, officials said.
The Metropolitan Water District of Southern California has plans to build a $6 billion facility in the city of Carson, south of Los Angeles, that would become the nation's largest water-recycling project.
Orange County's Groundwater Replenishment System, currently ranked as the biggest, earlier this year increased daily production to 130 million gallons, enough to meet the needs of 1 million people.
LARGE CITIES READY FIRST
Darrin Polhemus, deputy director of the state board's drinking water division, said it would likely take at least five years before the first direct potable reuse plant is operating.
Los Angeles and San Diego also have plans to develop direct potable recycling, as does the Santa Clara Valley Water District in the San Francisco Bay area.
Texas is the only US state to have previously approved direct potable recycling, with two small-scale systems that went online in 2014 to serve towns stricken by a drought-caused water emergency. Colorado also has developed relatively limited guidelines for such projects.
The technology for purifying wastewater is similar to that used in desalination, the seemingly more palatable process of converting salt water to fresh.
But recycling sewage is more environmentally friendly - lowering the amount of waste dumped into rivers and oceans while avoiding harm to marine life posed by ocean intake pipes used in desal plants and the highly concentrated brine by-product they discharge back into the sea.
Another desalination drawback is the comparatively high cost of removing salt from seawater, which contains 30 times more dissolved impurities than sewer water and thus takes far more energy to distil.
Polhemus said purified recycled water could eventually be expected to account for roughly 10 per cent to 15pc of supplies of some coastal communities in the midst of drought conditions.
