Tennessee Wastewater Operator Practice Exam

What is the method of algae control known as algistat?

1. Chemical treatment

2. Barley straw

3. Mechanical removal

4. Increased aeration

The correct answer is: Barley straw

The method of algae control known as algistat specifically refers to using barley straw as a biological control agent. When barley straw decomposes in water, it releases compounds that inhibit the growth of algae by impacting their reproductive processes. This approach is considered environmentally friendly and sustainable, providing a natural means to manage unwanted algal blooms in water bodies. Barley straw is often used in ponds and lakes to reduce the occurrence of harmful algae without introducing harsh chemicals that could negatively affect aquatic life. As it breaks down, the release of these compounds helps to create conditions that are less favorable for algae to thrive, thus supporting overall water quality and ecosystem balance. In contrast, the other options represent different methods of controlling algae. Chemical treatment involves synthetic substances that can kill algae, which may also disrupt the aquatic ecosystem. Mechanical removal consists of physically extracting algae from the water, and increased aeration enhances oxygen levels, which may help but does not specifically target algae control like barley straw does. Therefore, the most accurate identification of algistat lies in its association with barley straw.