填空题

Ultroviolet light has long been used in water-treatment plants to help with virus killing. As long as the water is clear enough not to absorb the rays, (36) it to a discharge lamp will destroy the DNA of viruses and (37) that could otherwise cause illness when (38) . Now a group of researchers have developed an industrial-scale solar-driven purification system that removes not only bugs but also chemical (39)
The first of their (40) has been built as demonstration project. The researchers wanted to clean the water that they use to cool their (41) engines. This cooling water (42) gets contaminated both with rocket fuel and with (43) produced by the burning of the fuel.
The trick the researchers use to boost the cleansing action of ultraviolet is to add a light-activated catalyst(催化剂) to the waste water. (44) . After a complex series of reactions, water gets pure enough to be discharged into a river. The system is capable of treating 4,500 litres of waste water in an hour or two. (45)
The project will be good at removing certain pollutants that are particularly hard to get rid of at the moment. Researchers say they will improve the system they have, (46)