sheeloopoonam@yahoo.com's blog

An aqua privy is not much different from a septic tank. The difference is that the latrine/s is located directly over the tank.
• The excreta enter it directly from the latrine through a drop pipe.
• This pipe is submerged under water inside the privy.
• This water directly acts as the water seal for one or more latrines opening into it.
A septic tank can treat wastewater from both the kitchen and the toilet, while an aqua privy is designed to handle only toilet waste.
Basic Design

A septic tank is an underground excreta (sewage) treatment system used in rural or suburban areas where there is no access to a centralized sewer system.
It’s a self-contained tank that collects and treats the human waste from one or more homes.
It is buried in the ground near the home/s. Think of it as the "middleman" between the excreta and the environment, filtering out harmful substances before the treated water is released back into the soil.
The tank is usually made of concrete, though fiberglass or plastic tanks are now available.

What Makes Up an RCA Latrine?
Whether it's the PRAI or RCA type, both have the same essential parts — only the technical details differ slightly. You’ll typically see:
1. A squatting plate
2. A pan for excreta reception
3. A trap for maintaining water-seal
4. A system positioned after the water seal, for safe and hygienic excreta disposal
 Connecting pipe
 The Pit (Dug-well)
5. A super-structure

What is a Water Seal?
• A ‘water seal’ is a simple but smart mechanism built into toilets and latrines.
• It’s usually a curved pipe, called a ‘trap’ - located just below the squatting plate or toilet bowl.
• This trap always holds a small amount of water due to its design.
If you've ever used a toilet, even in a rural area and noticed that it doesn't smell: you’ve one clever little feature to thank: i.e. the “water seal”.

How do Diseases Spread from Human Excreta?
Diseases can spread from human waste if not properly managed. When a sick person or a disease carrier passes excreta, it contains germs that can travel in different ways, including:
1. Water – Contaminated drinking water can spread diseases like cholera and typhoid.
2. Fingers – Poor hand hygiene can transfer germs to food and surfaces.
3. Flies – Flies pick up germs from waste and land on food.
4. Soil – Open defecation can pollute the ground, leading to infections.

Borehole Latrine: A borehole latrine is a deep, narrow pit drilled into the ground using mechanical or manual boring techniques.
• It may be lined with bamboo matting or earthenware rings to prevent collapse.
Dug-Well Latrine: A dug-well latrine consists of a wider, shallower pit that is manually excavated.
• It needs lining materials like bricks, stones, or concrete rings.

The limitations of a borehole latrine were:
• Limited capacity: The borehole filled up quickly, requiring frequent relocation.
• Specialized equipment: The construction process relied on an auger, which was not always readily available.

Bore-hole latrine can be seen as a sanitation milestone in India. It pioneered the advancement from service type to sanitary latrines.
• First introduced in the 1930s by the Rockefeller Foundation as part of a campaign against hookworm infestations
• It involved boring a vertical hole with a
o Diameter of approximately 30 to 40 cm (12–16 inches) and a
o Depth ranging from 4 to 8 meters (13–26 feet), with 6 meters (20 feet) being the most common.
• To create this borehole, a specialized tool called an auger was required.

What is ‘Excreta’?
Excreta refer to human waste, comprising both feces and urine. The methods of its disposal vary significantly based on cultural practices, economic conditions, water availability, and hygiene behaviors, such as the use of water or toilet paper for cleaning.

Why Should a Medical Student Care About Toilets?
As an MBBS student, you might think your primary focus should be on treating diseases, diagnosing conditions, and understanding human anatomy. But what if you are told that one of the greatest medical inventions isn’t a new drug, but a properly designed latrine?
Yes, something as simple as a ‘sanitary latrine’ can prevent millions of infections, reduce childhood mortality, and even improve nutritional outcomes.
First, what is meant by ‘Sanitary’?