Research and Development
On 24 December, 1988, His Majesty graciously granted another initiative to treat polluted water by adding air which can be done by two methods as follows:
One method is to compress air into the main pipe and expel it through diffuser tubes. The other method is to use a waterwheel to lift the water and return it. This waterwheel rotates slowly by using a small electric motor, not exceeding 2 horsepower, or using power from waterflow. It was considered beneficial to construct models of the aerator and experiment with them at Phra Mongkutklao Hospital and Bavornives Vihara Temple.
In accordance with His Majesty the King’s Initiative, the Royal Irrigation Department conducted a study and invented a model of the Chaipattana Aerator by modification of the flotation waterwheel pump. This aerator was installed to treat polluted water at Phra Mongkutklao Hospital and Bavornives Vihara Temple in 1989 as a plan to carry out further study, research and development of waste treatment systems for about four to five years.
Water & Oxygen, dissolved Oxygen
Water is a habitat not only for fish, but also for a lot of bacteria and plants. Similar to organisms on land, oxygen is necessary for them to survive. Fish and crustaceans have gills to absorb the oxygen for respiration. They need a minimum of 4 mg O2 per liter of H2O to survive without damage.
The capability of water to dissolve oxygen is 9.1 mg/l @ 20 °C (maximum, lower at higher temperature). But this is only a theoretical value. The actual value is lower, because of other substances dissolved in water or because fish absorb the oxygen. On the other hand it is increased by introducing oxygen through various mechanism.
The amount of dissolved oxygen is therefore a balance between absorber and donator, temperature and other substances dissolved. If this balance is seriously disturbed, one would speak of waste water or « น้ำเสีย ».
Qualifications
The Chaipattana Aerator, formally known as the Chaipattana Low Speed Surface Aerator, Model RX-2 (Royal Experiment Model 2), is capable of transferring oxygen up to 1.2 kilograms per horsepower per hour. Not only is the aerator effective in improving the quality of water, it is also easy to install and transport from one location to another. It is suitable for treating waste water in natural water areas like ponds, swamps, creeks, and canals in which the depth is more than one meter and the width more than three meters.
Functioning
The Chaipattana Aerator is capable of adapting to fluctuations in the water levels. The main components include:
1) Twelve arm buckets frame with a diameter of two meters.
2) Six of the 110 liters of water spraying buckets are perforated and attached to the rim of the frame.
- The water spraying buckets are rotated by transmitting power from a two-horsepower electric motor at a line voltage of 380 volts; 3 phase; 50 hertz.
- The transmission system uses a reduction gear motor, a roller chain and a sprocket. This allows the water spraying buckets to scoop water at five revolutions per minute and at a depth of 0.50 meters below the water surface, and to spray water above the water surface at a height of 1 meter.
The functioning of the water spraying buckets creates a large interface area between water and air, resulting in oxygen being quickly absorbed into the water. When waste water is scooped up, exposed to air, and then released, it creates air bubbles which eventually drop below the water surface. As each water spraying bucket rotates and presses down into the water, it causes air to compress in the bucket under the water surface until the bucket completely submerges in the water. This increases the effectiveness in transferring oxygen.
After oxygen has been added, the bucket will propel water at a low of 0.20 meters per second in order to push water away from the aerator at a distance of 10 meter. A by-product of the aerator is achieved from the movement of the floating vessel which causes the hydrofoil assy to stir and mix water with oxygen below the water surface. This movement simultaneously brings about a series of activity like adding air, stirring water in an integrated manner, and controlling the flow of waste water in a horizontal direction.
Countermeasures • Principles of Operation