At first glance, “zero discharge” (ZD)¾eliminating the discharge of any liquid waste to the environment¾seems like an idea of unqualified merit. It would be good for both the environment and any manager who achieves ZD. Let’s go back to the definition, though. The key word is “liquid”¾ZD doesn’t take into account solids. In fact, changing to a ZD operation ends up increasing the quantities of solids that have to be disposed. Disposal of solids¾those initially found in wastewater as well as those formed during the ZD treatment processing¾presents a significant environmental and financial liability of its own. In the past, this side effect has been enough to deter further consideration of this route. And the costs of equipment and energy necessary for achieving ZD are formidable. Why, then, is anyone even talking about ZD?