Which method is commonly used to control algae in greenhouse irrigation systems?

• A. Filtration and UV sterilization.
• B. Let algae grow to boost oxygen in water.
• C. Overheat the water to kill algae.
• D. Use untreated tap water.

Answer: (A)

Algae control in greenhouse irrigation relies on removing algae and inactivating microorganisms before the water reaches emitters. Filtration and UV sterilization do this effectively: filtration physically removes algae cells and particulates, reducing clogging and protecting drip lines, while UV sterilization inactivates the remaining algae, bacteria, and biofilms without adding chemical residues. This approach is widely used because it cleanly preserves water quality, minimizes chemical use, and is practical for recurring irrigation cycles. Letting algae grow leads to clogging and deteriorating water quality; overheating water wastes energy and doesn’t specifically target algae; using untreated tap water can introduce nutrients and organisms that promote algae growth.