经济学人:加州的海水淡化

IF CALIFORNIA were not already so famous for Silicon Valley and Hollywood, it might be renowned for the cluster of water-technology firms in its San Diego County. The reverse-osmosis (RO) spiral module, the trick that underpins turning sea- and waste-water into potable stuff, was patented in San Diego in 1964. Today dozens of firms in the area supply many of the world’s roughly 13,000 RO plants in places from the Persian Gulf and Israel to Australia, China, Singapore and Spain.
如果加利福利亚的出名不是因为硅谷和好莱坞，那么圣地亚哥大量的水处理公司也许会让它声名在外。反渗透膜元件1964在圣地亚哥被申请专利，该设备是将海水和废水转化为可饮用水的基础。当今全球约有13000家反渗透厂，它们分布在从波斯湾、以色列到澳大利亚、中国、新加坡和西班牙的地方。而其中的大多数厂商从圣地亚哥的水处理公司引进技术和设备。

Southern California itself, however, has not so far been a big user of its own technology. This is surprising, given that the whole American south-west confronts a water problem. But there is at least now a growing consensus that the existing infrastructure, consisting of vast aqueducts that carry water from the Sacramento Delta in the north and the Colorado River in the east, will not suffice as the climate gets warmer and the population increases. In places such as San Diego, which has measly and brackish groundwater and currently imports 90% of its water, the answer must be greater conservation, as much reuse as possible, with most of the rest coming from the sea.
然而到目前为止，南加州自身对水处理技术的运用并不广泛。这让人感觉到很惊讶，因为整个美国西南地区面临水资源匮乏问题。至少大家都逐渐认识到：随着气候变暖和人口增加，现存的基础设施（包括大量从北部的沙加缅度三角洲、东部的科罗拉多河铺设到西南地区的输水管道）将难以满足用水需求。圣地亚哥拥有的地下水储量既少，盐份又高，如今其90%的用水需从外地引入。在像圣地亚哥这样的地方，其对策是尽可能的节约用水、循环利用，而剩余不足的部份则大多从海洋中获取。

The first part, conservation, is hardly controversial any more. San Diego today uses less water with a larger population than it did in 1989, the year water consumption peaked. The second part, water recycling, has been a harder sell, because of what the industry calls the yuck factor. It doesn’t help that Americans still use the term “toilet-to-tap” for recycling, even though properly treated sewage is nowadays completely clean. Singapore made its programme acceptable in part by rebranding it as NEWater. But even the Singaporeans cannot recycle all their waste-water.
首先，节约用水已被广泛认同。圣地亚哥如今人口增加了，耗水量却比1989年（耗水量最高的一年）少。其次，水循环利用很难被广泛接受，其原因在于业内所称的“恶心之物”。美国人民称水循环为“马桶-水龙头”，即使被恰当处理的污水十分干净，其也难去除人们的恶心之感。新加坡使其在理论上被接受，部分原因在于它把处理过的污水称为新生水。但是，即使是新加坡人也不能循环利用所有的废水。

This is where desalination comes in. A firm appropriately called Poseidon Resources is now close to building the biggest desalination plant in America behind a power station by the beach in Carlsbad. The power plant sucks in 304m gallons of seawater a day for cooling in any case, so Poseidon plans to divert 104m gallons a day through its osmotic membranes.
海水淡化技术就因此出现了。恰如其名，Poseidon Resources公司将在美国修建最大的海水淡化厂，其厂址位于卡尔斯巴德的海滩附近的发电站后面。发电站每日总会吸取30400万加仑海水用于冷却，因此Poseidon计划每日用渗透膜淡化10400万加仑海水。

Fondling a pipe of membranes (they are rolled like toilet paper but the size of a cannon), Poseidon’s Peter MacLaggan explains the scale: if water molecules were blown up to the size of tennis balls, salt molecules would be softballs (roughly 50% bigger in diameter), viruses would be trucks, and bacteria would be the size of power plants. From the 104m daily gallons, 50m gallons of pure H2O will come out at one end and brine at the other, to be fed back into the power station’s discharge, and then into the ocean.
渗透膜如同卫生纸一样卷起来的，但却有大炮那么大。Poseidon的Peter MacLaggan一边摸着渗透膜一边解释道：如果水分子胀大到乒乓球大小，盐分子有垒球大（在直径上大约长50%），病毒有卡车那么大，细菌有发电厂那么大。在每天处理的10400万加仑海水中，有5000万加仑的纯水从渗透膜一端流出，然后在其另一端变成浓盐水，最终由发电厂的排放系统流回海里。

Lots of people like the idea. Once fully running in 2015 the plant could produce 10% of the region’s water. And there are plans for more desalination plants. Inland Californians, Arizonans, Nevadans and others would need to take much less water from the endangered Colorado River.
很多人赞同这种想法。到2015年，一旦Poseidon全部投入运行，其可以提供该地区用水的10%。而且有许多厂准备加入海水淡化处理队伍。加利福利亚内陆、亚利桑那州、内华达州和其它地方从日渐干涸的科罗拉多河中抽取的水将越来越少。

But a few people hate it a lot. Environmentalists are suing Poseidon every step of the way. Joe Geever of the Surfrider Foundation says desalination uses too much energy and that Poseidon’s plant would kill too much marine life, including fish such as the goby and the garibaldi, which unfortunately happens to be California’s state marine fish. He understands that there is a role for desalination, he says, but would rather not have it right there, right now, and on this scale.
但是也有一些人极不赞同。环境保护者正在起诉Poseidon海水淡化方式的每一步骤。冲浪协会的Joe Geever说：“海水淡化耗费太多的能源，而且Poseidon会伤害许多海洋动物诸如虾虎鱼、海金鱼之类的鱼类，而后者恰好是加州的海洋鱼。”他说，他知道海水淡化的重要性，但是相对于其来带的利弊，他宁愿加州此刻没有这么大规模的海水淡化厂。