sewage treatment plant onboard ship - biological sewage treatment plant in ship

Summary

This video explains the workings of a biological sewage treatment plant, consisting of four compartments. Raw sewage is first broken into smaller particles by a bar screen, then passes into the primary compartment. Overflow moves it to the aeration compartment, where bacteria break down the waste with the help of oxygen and nutrients. The liquid then flows to a settlement compartment for sludge separation. The sludge is recycled back, and the clear effluent undergoes disinfection with sodium hypochlorite before being pumped out. The process is automated using level floats for efficient operation.

Takeaways

• 🔍 The biological sewage treatment plant is composed of four interconnected compartments.
• 🔗 Raw sewage or effluent first passes through a bar screen that breaks it into smaller particles.
• 💧 The liquid then moves to the primary compartment, where it rises until it overflows into the aeration compartment.
• 🦠 The aeration compartment contains bacteria that require oxygen and nutrients to propagate, with the nutrient being solid waste material.
• 💨 Oxygen is supplied by bubbling compressed air through the broken-down waste, enabling aerobic activation.
• 📉 The liquid from the aeration compartment then passes to a settlement compartment, where activated sludge settles, leaving clear effluent.
• ♻️ The settled sludge is continuously recycled back to the aeration compartment to assist in the treatment process.
• 🧼 The clear effluent is then disinfected using a solution or tablets of sodium hypochlorite in the chlorination compartment.
• 📦 The discharge pump automatically lowers the level in the chlorination tank by pumping overboard.
• ⚙️ Automation is managed by high and low-level floats, with the discharge pump operating based on these levels.

Q & A

What is the primary purpose of the biological sewage treatment plant described in the script?

The primary purpose of the biological sewage treatment plant is to treat raw sewage or effluent by breaking it down into smaller particles, aerating it to encourage bacterial breakdown, settling activated sludge, and disinfecting the clear effluent before discharging it.

What is the function of the bar screen in the treatment plant?

The bar screen's function is to break up raw sewage or effluent into smaller particles as it passes through it.

What happens when the level in the primary compartment rises sufficiently?

When the level in the primary compartment rises sufficiently, overflow of the liquid takes place into the aeration compartment.

Why is the aeration compartment important in the treatment process?

The aeration compartment is important because it contains bacteria that require oxygen and nutrients to propagate. The solid waste material serves as the nutrient, and oxygen is supplied by bubbling compressed air through the broken waste, facilitating aerobic activation and breakdown of the sewage.

What is the role of the settlement compartment in the treatment plant?

The settlement compartment's role is to allow the activated sludge to settle, leaving a clear effluent. The settled sludge is then continuously recycled back to the aeration compartment to assist in the treatment process.

How is the sludge managed in the settlement compartment?

Since there is no oxygen in the settlement compartment, the sludge is continuously recycled to the aeration compartment, where it mixes with incoming waste to aid in the treatment process.

What process is used to disinfect the clear effluent before discharge?

The clear effluent is disinfected by treating it with a solution or tablets of sodium hypochlorite in the chlorination compartment.

How is the level in the chlorination tank managed?

The level in the chlorination tank is managed automatically by a discharge pump, which lowers the level by pumping the treated effluent overboard.

What role do high or low-level floats play in the automation of the discharge pump?

High or low-level floats automate the discharge pump. The pump cuts in at high levels and cuts out at low levels, ensuring the chlorination tank maintains the correct effluent levels.

Why is it necessary to recycle the sludge back to the aeration compartment?

Recycling the sludge back to the aeration compartment is necessary because it mixes with incoming waste, assisting in the biological treatment process by providing additional bacteria that help break down the sewage.