Upstream treatment is the first set of wastewater treatment processes. Its task is to prepare the wastewater for discharge to sewer or further treatment using biological treatment processes. Meat processing wastewater can be difficult to treat properly compared to other industrial wastewaters due to its:

• High levels of total suspended solids;
• High oil and grease concentrations ; and
• High temperatures.

The upstream, or primary, treatment processes used in the meat processing industry typically seek to reduce suspended solids, oil and grease and flow variations.