In many cases the most efficient way to reduce discharges is to alter production processes, recover materials, produce marketable goods from by-products, or change the nature or quality of raw materials.

• 在许多案例中，大多数减少污水排放的最有效方法是改变生产工序，回收废料，使用副产品生产销路好的产品，或者更改原材料的种类或性能。