Water is the source of life. In order to improve the living environment of people, the Ziyang Municipal Government strengthened the comprehensive management of Jiuqu River in 2011 and made due contrib

Water is the source of life. In order to improve the living environment of people, the Ziyang Municipal Government strengthened the comprehensive management of Jiuqu River in 2011 and made due contributions to the creation of a happy Ziyang.

(1) ① Eliminate domestic sewage and industrial wastewater outfalls along both sides of the river, and build new sewage treatment plants; ③ Prohibiting residents along the river from washing clothes in the river can protect the water environment.

②Constructing riverside landscape belts has nothing to do with protecting the water environment;

So the answer is: ②.

(2) The water plant processes the river water through sedimentation, filtration, and sterilization, and then delivers it to thousands of households.

So the answer is: filter.

(3) The reaction of iron nitrate, sodium hydroxide, chlorine and other substances can produce sodium nitrate, sodium chloride, sodium ferrate and water. The chemical equation of the reaction is: 2Fe(NO3)3+16NaOH+ 3Cl2═6NaNO3+6NaCl+2Na2FeO4+8H2O．

So the answer is: 8H2O.