There are several synonyms for the phrase "waste disposal units". One of the most common synonyms is "garbage disposals". These are devices that are installed in kitchens to grind up food waste and flush it down the drain. Other synonyms include "waste management systems" and "trash compactors". Waste management systems are typically larger and more complex than garbage disposals, and they are used in commercial and industrial settings to handle large volumes of waste. Trash compactors are also frequently used in commercial and industrial settings, and they are designed to compress trash into smaller volumes for easier storage and disposal. Regardless of the specific synonym used, the goal of these devices is the same: to make waste disposal more efficient and environmentally friendly.