Final answer:
The four types of surface wash systems are aeration, filtration, sedimentation, and coagulation and flocculation; these processes aim to purify and treat water by removing impurities and contaminants.
Step-by-step explanation:
The four types of surface wash systems in the context of wastewater treatment are aeration, filtration, sedimentation, and coagulation and flocculation. Aeration is a process of bringing air in contact with water to exchange components between the two phases for purposes such as oxygenation and removal of unwanted substances. Filtration involves passing the clear water through various filters to remove particles, bacteria, and viruses. Sedimentation is where water moves through tanks allowing floc particles to settle to the bottom. Lastly, coagulation and flocculation involve adding chemicals to water that bind with impurities to form larger particles that are easier to settle and remove.