Showing posts with label Recycled Water. Show all posts
Showing posts with label Recycled Water. Show all posts

Thursday, June 14, 2012

Good News On Using Recycled Sewage Treatment Plant Water for Irrigating Crops


A new study eases concerns that irrigating crops with water released from sewage treatment plants -- an increasingly common practice in arid areas of the world -- fosters emergence of the antibiotic-resistant bacteria that cause thousands of serious infections each year. The research appears in ACS' journal Environmental Science & Technology.

Eddie Cytryn and colleagues explain that a large fraction of antibiotics given to people or animals pass out of the body unchanged in the urine and are transferred via sewage systems to wastewater treatment facilities. These facilities do not completely remove common antibiotics like tetracycline, erythromycin, sulfonamide and ciprofloxacin and may actually enhance the abundance of antibiotic-resistant bacteria and antibiotic-resistance genes.

Previous studies have suggested that wastewater effluents can expand natural reservoirs of antibiotic resistance, which may contribute to clinically associated antibiotic resistance. Arid and semi-arid areas of the world are plagued by severe water shortages, which are expected to increase as a result of growing population and global climate change. As a result, more areas are turning to treated wastewater (TWW) to irrigate croplands. In Israel, for instance, TWW provides more than half of the water used for irrigation. The researchers wanted to find out if long-term irrigation with treated wastewater enhances antibiotic resistance in soil microbial communities, which could potentially be transferred through agricultural produce to clinically relevant bacteria.

The authors found that levels of antibiotic-resistant bacteria and genes for antibiotic resistance in fields and orchards irrigated with freshwater and TWW were essentially identical, suggesting that antibiotic-resistant bacteria that enter soil by irrigation are not able to survive or compete in that environment. The authors say there is "cause for cautious optimism" that irrigating with TWW is not increasing the prevalence of bacteria resistant to the antibiotics they studied.

The authors acknowledge funding from the Israeli Ministry of Agriculture and Rural Development and the Environmental Health Fund.


Tuesday, May 8, 2012

‘Ick Factor’ Fouls Toilet-to-Tap Sewage Water Recycling

For all the concern about how we’ll feed a projected 9 billion people by 2050, there’s little talk about where everyone will go to the loo. How we'll move all that waste away from where people live -- plumbing -- is just one issue. With some 2.6 billion people, or 40 percent of the world’s population, already lacking adequate drinking water, building the right sanitation infrastructure today is a foundation for public health and economic development for decades to come.

Rose George has probed these issues for years, most notably in her 2008 book The Big Necessity: The Unmentionable World of Human Waste and Why it Matters, a look at toilets, sewers and water around the world. We spoke last month about the world’s dwindling supply of fresh water and its ever-increasing volumes of sewage.

Q: This isn’t the easiest topic to bring up in polite company. How does common avoidance of this topic interfere with solving problems? 

A: If you work in sanitation you have to pay attention to psychology. People are quirky and irrational and perverse. In some areas, treated wastewater is pumped into a local aquifer, before it’s withdrawn as clean, “natural” fresh water. It’s just a sleight of hand. The water is perfectly clean when it leaves the sewage treatment plant. It’s actually dirtier once you pump it out of the aquifer or a river.

Q: Even though we know intellectually that it’s fine, many people just don’t want to hear about clean, healthy drinking water that’s been through the sewage system. It’s the idea of it. 

A: It’s what we call the toilet-to-tap "ick" factor. NASA astronauts have been drinking recycled urine for ages. If you’re drawing from any single major lake in the U.S., you are already drinking someone else's discharge. I'm probably a bit too blunt about it.

Q: But bluntness probably helps sometimes, too, I imagine.
 
A: If you disgust people enough, they immediately change their behavior and rush off and build latrines. You can encourage change with prize-giving or in developing countries make it a competition with a neighboring village. The Bill and Melinda Gates Foundation has started a program in India to encourage brides to insist their husbands build them a toilet before they agree to marriage, it’s called “No Loo, No I Do.”

Q: How bad is the problem in the U.S? 

A: Some reports say nearly 2 million Americans live without proper plumbing or sanitation.

Q: Biologists tell us that in nature there’s no such thing as waste. Everything just becomes something else. That sure doesn’t seem like it’s the case in cities.
 
A: A really astonishing fact is the absolute scorn for seeing sewage as a resource. Only about 500 of the 16,000 wastewater treatment plants in the U.S. do anything with the waste they pull from the water. Marco Polo saw bio-methane being used in China. One hundred and fifty years ago we had streetlamps powered from sewer gas. Most sewage plants just flame off the methane. In England Thames Water says it's saving 15 million pounds a year [almost $20 million] on electric bills because they use the methane.

Q: How do you upgrade, in short order, the 2.6 billion people without proper sanitation? Or can you?
 
A: I’ve spoken to big companies and they say people are too poor. That’s a gross misunderstanding. People will buy something if they see its value – and that includes toilets. In fact, the big buzz in the sanitation world for the toilet-less is sanitation marketing. We’ve learned over the years that you can’t just give someone a toilet. You have to make it a consumer product, like the Japanese did.

Q: Are toilets the answer everywhere?
 
A: Before, the idea was that everyone has to aspire to a flush toilet and sewer system, but that’s inappropriate for any country with a shortage of water. The answer now is whatever works.

Q: Is this a wholly systemic problem, or are there things consumers could make an impact with?
 
A: The most important thing we can do is stop discarding waste in water, and start thinking of it as a resource. Ideally we'd all have self-contained composting toilets in our apartments, but that's not going to happen. It could be simple things like not flushing as much. If everybody flushed a few times a day less that could have a real impact. And we must look at the costs beyond money. New York City is discharging raw sewage into its waters every time it rains, so that has an environmental cost. [New York's fateful 19th-century decision to build a single set of pipes to carry away sewage and storm water has left today's sewage treatment plants unable to cope with the flow when heavy rains hit -- P.G.]

Q: How do you get all the players -- the consumer, the state, utilities -- to pay attention to the sewage crisis?
 
A: Sewage ought to get attention simply from the day-to-day deaths from diarrhea in the developing world -- preventable deaths. It is completely ignored. Basic, boring diarrhea doesn’t get any attention. There's still a lot of squeamishness and there needs to be a bit more courage to talk about it.

Q: What are you doing now?
 
A: Working on book about merchant shipping and the sea. I went pirate-hunting. I was on a container ship for six weeks.

Q: What the most memorable book you've read lately?
 
A: The Urban Whale, by Scott D. Kraus and Rosalind M. Rolland. It's about the North Atlantic Right whale, New York's local whale, about how industry is having an impact on the ocean and its wildlife. It's enlightening.

Friday, January 27, 2012

Vietnamese Try to Regenerate Water Waste

According to Dr Nguyen Phuoc Dan, Dean of the Environment Faculty of the HCM City University of Technology, the surveys show that the urban areas in the key southern economic zone are bearing a hard pressure, which requires applying the measures to minimize the use of fresh water in the region.

He said that it is necessary to encourage or to force the subjects which use much water, to use recycled water, and if so, the demand for recycled water may reach 1.5 million cubic meters per day.

Using recycled water will help HCM City save money and reduce the overspending, while it would be able to control the water sources to be used in dry season, and ease the reliance on the water sources from water reservoirs, minimize the pollution.

Of the subjects that need to use recycled water, the demand from civil activities and irrigation is believed to account for a big proportion. Besides, recycled water would also bee needed to regenerate the landscapes, such as putting the river flow through, restore the water resources for the polluted river and canal systems and create urban landscapes

One of the most important purposes of the plan on using recycled waste is to ensure the health of the community. Therefore, the recycled waste water needs to be treated to meet the standards of reducing or eliminating pathogenic bacteria, parasites, intestinal virus in recycled water, the composition of the hazardous chemicals in recycled water.

Recycled waste water can be safe for health

Dr Dan, leader of the research team, said that the water recycling technology chosen for consideration is the processing technology with biological activated carbon (BAC) and bio-sand filter (BSF). A model with the testing scale of 2 cubic meter per day has been installed at the Binh Hung Hoa waste water treatment station in Tan Phu district of HCM City.

After the experiencing period, scientists have decided to choose the 2-3 m/h filtration speed for BAC-BSF technology as the solution for recycling waste water, which brings relatively good effects, while the process of nitrification and nitrate reduction can go well.

The research work has brought the results which can meet the standard quality, in accordance with the regulations of the World Health Organization WHO.

According to scientists, users can choose to use recycled water based on their demand. Recycled waste water can be divided into three grades, low, medium and high. The low and medium grade recycled water can be used for watering plants, serving at parks, cleaning industrial machines, cleaning toilets, distinguishing fire, watering the roads. The costs prove to be reasonable to the purposes of use, at 4000 dong per cubic meter.

The research work by the team from the HCM City University of Technology has been highly appreciated by scientists.

“In HCM City, the recycling and reusing of waste water after treatment for different purposes has been considered and developed in the first stage to clarify the scientific foundation and the possibility of applying the research in reality. The research work of the scientists from the HCM City University of Technology has affirmed this,” said Professor Dr Lam Minh Triet, Head of the Institute of Water and Environmental Technology, vice president of Nature and Environment Protection of Vietnam - VACNE).