电视报道一个大型净水厂，把厕所排污的废水经过n道工序再生为可饮用水（看到镜头里的厕所污水，水还敢喝？比地沟油还恶心啊）。可专家说，循环再 生的水质比一般饮用水更好，口感和卫生均佳，但考虑到民众对这种污水净化有心理抵制，头两年这种水主要用于浇水和其他使用。等民众习惯了，再正式作为饮用水进入千家万户。

不远的将来，我们就要喝地沟厕所水了。呜呼

懂科学的网友科普一下，为什么地沟水似乎可以接受，地沟油就不行？是工艺不过关么？

其实地沟油回收如果质量不过关，不食用，而是做其他用途，比烂在臭沟里要造福人类哎，主要是管理不到位，不是地沟油概念本身的问题，不是？以前也有报道，旧金山政府有专门负责回收搜集废油的，到中餐馆等地。

注：加州应指“美国加利福尼亚州，原链接失效。相关消息见附6.

附6：http://www.cacoastkeeper.org/news/making-sewage-water-good-to-drink（加州环保类网站）

                                             MAKING SEWAGE WATER GOOD TO DRINK（使地沟水可饮用）

                                           Valley District, San Jose look to ensure adequate future supply.

                                              Paul Rogers，San Jose Mercury News，09/25/2007

The Santa Clara Valley Water District and the city of San Jose are beginning talks on a bold new strategy to boost water supplies: making sewage water clean enough to drink.

If the public backs the plan, one day millions of gallons of the purified water could be pumped into streams and groundwater aquifers across Santa Clara County and mixed with existing drinking water supplies.

The county now provides half of its drinking water from wells that pump water from those aquifers. The other half comes from the Sacramento-San Joaquin River Delta.

"This is a homegrown resource. It is the most reliable supply you can have," said Eric Rosenblum, division manager for San Jose's South Bay Water Recycling Project.

"It is much less dependent on the weather than other sources. It is a great new tool to meet water needs."

The potentially controversial idea, still in the early stages, will be discussed this morning at the water district's weekly board meeting in San Jose. A final, detailed proposal isn't expected until next year.

Experts note that the technology exists to take sewage water and purify it to levels that meet California drinking water standards using an array of techniques such as reverse osmosis, microfiltration and ultraviolet light.

But in several areas around California - from San Diego to Pleasanton - attempts at blending purified wastewater with drinking water aquifers have been dropped after public outcry from critics who call the projects "toilet-to-tap."

But some water districts have already moved ahead with projects.

The Orange County Water District will christen a new $480 million project in November to produce up to 70 million gallons of recycled water a day from treated sewage. It will be used to recharge drinking water aquifers that serve Anaheim, Huntington Beach and other cities.

The project - the largest of its kind in the United States - came after nine years of public hearings and scientific studies. It won permits from the U.S. Environmental Protection Agency and the state Department of Public Health.

Cautious approach

Keith Whitman, water supply manager for the Santa Clara Valley Water District, promised that the district will take a similarly cautious approach.

"What we don't want to end up with is what's happened in other areas where you have fear and politics cause a backlash," he said.

Because California's population is expected to grow from the current 37 million to more than 52 million by 2030, the state Department of Water Resources recommended four years ago that California triple its use of recycled water, now about 500,000 acre-feet a year, by 2030.

Nearly all the recycled water in the state, however, goes for non-potable uses such as irrigating crops, cooling power plants, and watering golf courses, cemeteries and highway landscaping.

San Jose has used it in those ways for a decade.

In 1997, the city began delivering recycled wastewater across the county through purple pipes from its sewage treatment plant in Alviso. The project now has 540 customers and provides about 10,000 acre-feet of water a year - nearly 3 percent of total county demand. An acre-foot is about 326,000 gallons, or the amount of water a family of five uses in a year.

Customers for recycled water include San Jose Municipal Golf Course, Metcalf Energy Plant in South San Jose, Oak Hill Cemetery and dozens of schools and parks.

The city sells the water at a discounted rate. Originally, the $225 million project was built after state water regulators ordered the city to stop pumping so much treated fresh water into San Francisco Bay, where it was diluting brackish marshes and changing the bay's ecology.

But now, the city and the water district see the project as a potentially significant source of drinking water.

Today, the water district board will vote whether to allow its staff to negotiate with the city to expand the use of recycled water. If approved, as expected, the final agreement would come next year.

No project would be built without public hearings, an environmental impact statement, approval from the state Department of Public Health, the Regional Water Quality Control Board and the San Jose City Council.

In early feasibility studies, the water district has envisioned constructing a $52 million advanced treatment plant. It would be located in Alviso next to the city's wastewater treatment plant and produce the same amount of recycled water now produced by the plant, about 10 million gallons a day, but at a higher quality. It would remove salts that, if left untreated, would eventually build up in irrigation water, causing grass to brown and harming redwoods and other trees in clay soil.

Could open by 2012

Whitman said construction could begin on the plant by 2010 and open by 2012.

After that, if the city and district want to blend its recycled water with groundwater aquifers, they would build one or more "satellite plants" in places like Coyote Valley and further treat the water to drinking water standards.

The state Department of Public Health requires any recycled water used on food crops, school fields or residential irrigation to be treated to tertiary standards - the highest level of sewage treatment, and disinfected with chlorine. San Jose's now meets that standard.

But the health department does not have uniform guidelines for pumping it into drinking water aquifers. New rules the department is drafting would require it to meet drinking water standards.

Environmentalists are generally supportive.

"Recycled water is going to be a critical component of California's water future," said Linda Sheehan, executive director of the California Coastkeeper Alliance, in Fremont. "It has to be, because of population growth and because climate change is going to reduce the amount of snowpack in the Sierra."

Sheehan said, however, that the water must be rigorously tested not only for traditional contaminants such as bacteria but also for minute levels of pharmaceuticals, hormones and other contaminants that can get through sewage treatment plants unfiltered.

The largest hurdle if the project is to go forward is the "yuck factor." Even if the science is sound, how do you persuade people that it is OK to drink toilet water?

In Sonoma County, some vintners have been fighting a proposal this summer to use recycled water from Santa Rosa to irrigate wine grapes.

"I am worried that there is a huge backlash on recycled water on our grapes," Katie Murphy, vice-president of the Alexander Valley Association, told the Santa Rosa Press Democrat in May. "I fear negative publicity - and that could linger over our wine industry for a long time."

In Orange County, water officials held hundreds of public meetings with hospitals, civic groups, religious leaders and others. They noted that astronauts have drunk recycled water for years - and that anyone drawing water from a river is drinking the recycled wastewater of cities upstream, as Los Angeles does with Las Vegas, and Memphis with St. Louis.

"We are very concerned about public opinion," said San Jose's Rosenblum. "People in Silicon Valley value innovation and technology, but they also value a high quality environment and a reliable source of water. So to the extent that using recycled water for potable purposes helps achieve those goals, I think the people in our area will be open to its use."

附7：http://zjnews.zjol.com.cn/05zjnews/system/2009/03/23/015367522.shtml

　　新华网3月23日电 啤酒、墨水，甚至地沟水等各种污水，经过一台净水器处理后都可以成为饮用水。这是宁波大学与浙江大学等单位合作完成的"节能型饮用水深度处理系列设备的研发与产业化"项目的核心成果，并获得国家科技进步奖二等奖。

　　据该项成果主要负责人之一的宁波大学教授陆茵介绍，这种水净化技术以超亲水膜为核心技术，膜上的孔既小又密，孔的直径相当于万分之一的头发丝，一张膜上至少有十亿个微孔，几乎可以100%地过滤掉细菌杂质。

　　这种膜具有极大的亲水性，使水能够不用外界压力而达到净化的效果，自来水龙头的水，就可以直接在净水器中过滤，无需额外的压力装置，从而减少了成本。

　　我国淡水资源匮乏，水污染成为一个环保问题。研究人员说，即使是纯净水从出水厂门到入百姓家，要经过长距离输送管网、高层水箱以及某些低劣的饮水机，其间可能产生的二次污染，威胁饮水安全。利用亲水膜，把它安装在小型的净水器上，可使用户喝上健康水。

附8：http://old.cxnews.cnnb.com.cn/gb/node2/node3/node21/userobject1ai98481.html