Final answer:
It is true that grease removal from wastewater with a pH below 7 is more difficult as acidic conditions can cause grease to remain in suspension, making it harder to remove.
Step-by-step explanation:
The statement that grease removal from wastewater with a pH below 7 is more difficult since grease tends to remain in suspension if the wastewater pH is below 7 is true. Grease can become emulsified in acidic conditions (pH <7), which means it is dispersed throughout the water, making it harder to separate and remove. Proper pH levels are important for optimal treatment processes in wastewater management.
For example, during wastewater treatment, selective precipitation is used to remove various contaminants, and this process can be sensitive to pH levels. When the pH of wastewater is neither too acidic nor too alkaline, treatments like flocculation, which helps to aggregate suspended particles including grease, can occur more effectively. In contrast, very acidic conditions can prevent the successful aggregation of these particles, holding them in suspension and hindering treatment processes like primary solid removal.