15 Raw sludge, no matter from primary or secondary settling, will not drain well on sand beds and will usually have an obnoxious odour.
15 Raw sludge, no matter from primary or secondary settling, will not drain well on sand beds and will usually have an obnoxious odour.
生的（未经处理的）泥浆，无论是来源于初次或者二次的沉淀，都不会很好的渗漏在沙床上而且会散发难闻的气味。