沉降池中的废水中加入了消毒剂，以消灭所有有害微生物。Effluent from the sedimentation tank is dosed with disinfectant to kill any harmful organisms.控制颗粒污染物的技术包括过滤 、 洗涤 、 离心分离 、 静电沉降.Techniques for controlling particulates include filtering, washing...
the need to improve facilities for leisure and recreation改进消遣娱乐设施之必要There are excellent facilities for sport and recreation.有完善的体育娱乐设施。What kind of recreation do you go in for?你在文娱方面有什么爱好?...