請將下列專業英文翻譯成中文:(20 分)
Water, oil, and other substances collect at the bottom of the ship in what is
known as the bilge. Bilge water is pumped overboard, but must pass a
pollution threshold test of 15 ppm(parts per million)of oil to be discharged.
Water is tested and either discharged if clean or recirculated to a holding tank
to be separated before being tested again. The tank it is sent back to, the oily
water separator, utilizes gravity to separate the fluids due to their viscosity.