Flashcards on Tertiary Wastewater Treatment
Tertiary Wastewater Treatment: Processes & Purpose
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Maturation Ponds (Wastewater Treatment)
14 cards
Card 1
Question: What is the primary purpose of a maturation pond in wastewater treatment?
Answer: To continue natural purification of effluent, improving quality (especially bacteriological safety) by additional retention; often used in series for
Card 2
Question: What is the recommended minimum total retention period for maturation ponds?
Answer: About 10 to 12 days.
Card 3
Question: How do maturation ponds function as a buffer in a treatment system?
Answer: They provide storage capacity to buffer the system in the event of a malfunction in the treatment works.
Card 4
Question: Why are maturation ponds considered a high safety barrier?
Answer: They offer a high safety barrier against bacteriological pollution of the receiving water.
Card 5
Question: With which types of prior treatment should maturation ponds be used?
Answer: Only in conjunction with well purified humus tanks (secondary treatment) or sand filtered effluent (tertiary treatment).
Card 6
Question: Name three things maturation ponds are NOT intended to do.
Answer: (a) Cater for under-designed conventional wastewater plants; (b) Obviate extension of an overloaded treatment works; (c) Save on cost of operation and
Card 7
Question: How should maturation ponds be divided and why?
Answer: Into a number of smaller ponds in series, preferably 6 or 8, to eliminate short-circuiting and ensure maximum retention for purification.
Card 8
Question: What depth may be required for maturation ponds in areas with bulrush growths?
Answer: They may need to be 2 m or 3 m deep.
Card 9
Question: What is the recommended slope and bank width for stability and maintenance access in maturation ponds?
Answer: Bank slopes should not be steeper than 2:1; walls between ponds should preferably exceed 3.5 m in width for proper compaction and maintenance access.
Card 10
Question: How should pond walls be protected against wind erosion and water infestation near the waterline?
Answer: Protect about 300 mm above and 300 mm below the waterline with rock-fill or concrete.