Collingwood R W
Ciba Found Symp. 1977(57):229-42. doi: 10.1002/9780470720387.ch12.
Of the 41 kt of phosphorus reaching the sewage works in England and Wales 15 kt is removed in sewage sludge and the remainder is disposed of to rivers. 60% of the sewage sludge is now used as fertilizer and this proportion will no doubt increase in the future. The total use of sewage sludge, however, represents only about 5% of the current annual usage of artificial phosphorus fertilizer. At present there is no general economic incentive to make better use of the phosphorus in effluents. Phosphorus removal is expensive--about 2--3 pence/m3. If all the sewage effluents in England and Wales were to be so treated the cost would be about 100--150 million pounds annually, that is about 50% of the present costs of sewage treatment. In certain cases, but rarely in the UK, phosphate is removed, not to conserve phosphorus but to minimize the problems it creates in the environment. The phosphorus removed has little value as fertilizer. Alternative methods of using the phosphorus in effluents by the production and harvesting of crops of algae or aquatic plants have so far proved uneconomic. However, these methods need to be reviewed periodically as they may in the future become economically more attractive, especially in warmer climates where plant growth can be maintained throughout the year.
在进入英格兰和威尔士污水处理厂的4.1万吨磷中，有1.5万吨在污水污泥中被去除，其余的则排入河流。现在，60%的污水污泥被用作肥料，而且这一比例在未来无疑还会增加。然而，污水污泥的总使用量仅占目前人工磷肥年使用量的5%左右。目前，并没有普遍的经济激励措施来更好地利用废水中的磷。除磷成本很高——约为每立方米2至3便士。如果要对英格兰和威尔士的所有污水进行这样的处理，每年的成本将约为1亿至1.5亿英镑，即约占目前污水处理成本的50%。在某些情况下，但在英国很少见，去除磷酸盐不是为了节约磷，而是为了尽量减少它在环境中造成的问题。去除的磷作为肥料价值不大。通过生产和收获藻类或水生植物作物来利用废水中磷的替代方法，目前已证明不经济。然而，这些方法需要定期审查，因为它们在未来可能会在经济上更具吸引力，特别是在全年都能维持植物生长的温暖气候地区。
