Which factor is commonly associated with regulated waste from the tanning industry?

The correct answer highlights that waste from the tanning industry is typically characterized by high salts and high biochemical oxygen demand (BOD). Tanning processes often involve the use of various chemicals, including salts such as sodium chloride, as well as acids and bases for pH adjustments. These chemicals contribute to the generation of high levels of salts in the wastewater.

Additionally, the tanning process itself generates organic materials, primarily from animal hides, which leads to a high BOD. BOD is a measure of the amount of dissolved oxygen needed by aerobic microorganisms to decompose organic matter present in the water. The combination of high salts and high BOD poses significant challenges for wastewater treatment systems, as they must handle both the chemical burden and the organic load to effectively treat the effluent before it is released into the environment.

Understanding this characteristic of tanning industry waste is crucial for managing its treatment effectively and ensuring compliance with environmental regulations.