这可能来自于生产阶段的粪肥和水，有可能是在加工处理过程中来自于周围的环境，还有可能是在包装环节由于缺乏卫生设备造成的。
It can occur during production, from manure and water, during processing from environmental sources and during the final handling and packing, possibly as a result of poor human sanitation.
更糟糕的是，团队经常会过于庞大，这是因为每一个领域都有可能使用新的、小型的处理过程框架潜在的增加工作量。
Worse yet, the team often grows too large because every area that could potentially mount a work effort using the new, smaller process framework must be represented on it.
近年来，磁载体法已经在生物细胞分离，废水处理，燃煤脱硫和矿物加工等过程中得到广泛地应用[4,5]。
In recent years, the magnetic carrier method has been widely applied in biology cell separation, wastewater treatment, coal desulfurization and mineral exploitation [4, 5].
应用推荐