Daily droppings feed, water crops

When you flush the toilet in Beijing, your urine and feces doesn't magically disappear, but comes back to your daily life in unexpected and sometimes intimate ways.

The solid waste becomes high-grade organic fertilizer and nurtures the food available on store shelves and in restaurants. And the liquid waste is purified then used to make the concrete buildings you live in, to clean the streets you walk on, and even water the crops you eat.

Beijing has always recycled its "night soil."

Night soil neatly enfolds a phrase used historically and euphemistically to mask the stench of its meaning, put simply: human excrement.

Yet night soil refers more specifically to human feces in an age-old method of waste management.

Neither its basic substance nor the intents and purposes of night soil treatment have changed since its earliest use as far back as Attica.

Traditionally, the treatment would take fecal matter from cesspools and privies to be used as fertilizer in areas away from human habitation.

Today, night soil treatment is still a vital requirement for managing and sustaining the developing infrastructures of cities and rural communities worldwide.

Once dealt with by hand exclusively during nighttime hours, this method of waste treatment now commonly operates during daytime under advanced technology.

The modern use of this method shows to be increasingly effective in reusing waste in a way that is ecologically friendly and protective against disease of overpopulated areas.

Beijing Century Green Environmental Engineering and Technology (CGEET) is Beijing's leading company for the facilitation of collection and percolation technology used on city's waste system.

CGEET has existed for ten years and is headed by Wang Shaokang, a graduate of Beijing's Steel Institute and former head salesman of German company Hans Huber.

Wang Shaokang, 60, agreed to speak in depth to Metro Beijing about the modern process of night soil treatment in one of the world's most densely populated cities.

In the thick of it

"In 2009, Beijing produced 5,700 tons of excrement per day. Since then, the number has risen to 6,300 tons," Wang told Metro Beijing.

Of this tonnage, which has risen due to Beijing's population increase, Wang said treatment methods manage to collect the majority of the city's waste from public and residential toilets in large underground septic tanks.

The tanks, he went on, are then extracted from by sucking devices loading large trucks with waste product before being transported away for different uses.

"We separate the night soil into solids and liquids," Wang said. "The solid is later dehydrated, while the residual liquid is cleaned and purified. The dehydrated solid includes garbage and dry feces, the latter of which is reused as high-quality organic fertilizer."

Wang clarified the 'cleaning' of waste liquids is a high level filtering process that extracts and purifies liquids from feces.

This by-product liquid is then used suitably for cement-mixing, road cleaning and "even watering the rural outskirts of Beijing."

Metro Beijing then requested that the list of objects and substances frequently discovered in the collection tanks of Beijing's sub-terrain be given.

"Besides human waste," Wang began, "we often find plastic bags and huge amounts of women's sanitary towels. Then, towards the bottom of each tank, we have found underwear and other random items of clothing, condoms, elderly people's canes, wine bottles, dead cats and," he confessed hesitantly, "even what appear to be the traces of dead fetuses."

The underground septic tanks typically yield three layers of waste through slow filtered separation.

The top layer consists of dehydrated feces, while the middle consists of reusable liquids. Finally the third, bottommost layer consists of miscellaneous sewage, which, according to Wang, deals effective management of Beijing's waste system its biggest hindrance.

Bad odors linger

The treatment of night soil in Beijing remains, like most of the city's infrastructural support, both ever-changing and in need of constant adaptation.

The first mechanized night soil treatment system was introduced to China from Germany in 1994, while the first fully mechanized night soil treatment station was completed in 1997 in Gaobeidian, Beijing.

Traditionally, night soil treatment would take the form of manual work. In ancient and developing China, night soil was collected using wooden "honey buckets" attached to shoulder poles and collected by foot door-to-door in rural villages before being transferred to rural farmland.

Night soil treatment has throughout history courted a reputation for foulness and public revulsion. In the surviving Hindu caste system, night soil workers held the degrading status of "untouchables."

While Wang pointed to new technological advancements that today deodorize working environments and help to make night soil treatment more discreet, founder of the World Toilet Organization Jack Sim offered an alternative perspective on the issue of odor.

He argues that the toilet related health hazards in Beijing's are in fact caused by people's coping mechanisms for dealing with their unpleasantness.

Sim said he believes one of the things "most unreported" about Chinese public toilet systems is people's attempts to mask unpleasant smells by smoking, which ultimately leads to worse consequences than bad hygiene or underdeveloped waste removal.

"Cancer rates among men in China are particularly high at present. If the toilet systems didn't smell quite as much, maybe there would be fewer smokers," he said.

Flush funds wanting

Though the municipal government of Beijing has recognized night soil treatment as a priority for effectively improving the city's standard of hygiene and sustainability, long-term government funding remains only a half measure, according to Wang.

"In 2000, after the successful bid of 2008 Olympic Games," he explained, "Beijing tried to become cleaner and more modernized. Jia Qinglin (fourth-ranking member of the Politburo Standing Committee) asked the director of Beijing municipal administration to develop our own technology on night soil treatment, and the chair of Beijing environmental sanitation engineering research institute approved."

Wang finished by saying that although companies like CGEET prove consistently instrumental in cleaning up the city's unseen waste, the awards it receives from the government are not what is really needed to deal with Beijing's "worsening overgrowth."

Funding for future sustainability, Wang insists, needs to be both "reliable and to contain foresight," adding that "awards, though they pay a huge compliment, do not advance the goals of correctly tackling Beijing's ongoing waste issue."

With this, the phrase "night soil" will likely survive for decades to come as polite code for that which few, as ever, are willing to dirty their hands with.