Avoid emptying mis-filled bottles into drains. Instead, collect the beer in a tote or container for disposal.
Minimize keg foam and beer overflow when washing down the filled kegs. While not a major contributor to wastewater strength, it is something that can be minimized through equipment options and practices.
If a brewery has an off-spec batch, dumping it down the drain all at once can cause significant problems for municipal treatment plants and sewer systems.
The brewery should contact their local treatment facility before any discharge, to discuss when and how to deal with the off-spec product.