An apparatus for treating wastewater (1) based on biodegradation-recombination-biodegradation process, comprises:
- a shell (1.1) comprising two halves facing each other;
- the space inside the shell (1.1) is divided into a first chamber (1.2) and a second chamber (1.3) by a divider wall (1.4), wherein:
- the first chamber (1.2) contains biological medium suitable for heterotrophic microorganisms growth, and is divided into three regions, in order from top to bottom, including:
- an upper region (V1) has a mixing chamber (A) for receiving wastewater and clean water and mixing the clean water to the wastewater to dilute the wastewater before treatment, and a water sprayer (R) located above the upper region (V1) for spraying clean water to wash garbage,
- a middle region (V2) contains biological beds (1.6) for immobilizing aerobic microorganism, said biological beds are held in a support frame (1.7), wherein the support frame (1.7) itself is an air duct for conveying air from an air blower through a valve (K4) and diffusers located in lower part of the support frame (1.7) to wash sludge out of the biological beds (1.6) located in the first chamber (1.2),
- a lower region (V3) for receiving settled inorganic sludge and a part of organic sludge,
- a vertical pipe (1.8) passes through the biological beds (1.6) in the middle region (V2), has a lower end connected to the lower region (V3) and an upper end is higher than a water inlet pipe of the first chamber (1.2) so that water in the upper region (V1) does not directly overflow into the vertical pipe (1.8) when the apparatus is in normal mode,
- a horizontal pipe (1.9) is connected to the vertical pipe (1.8) at a position higher than the middle region (V2), passes through the divider wall (1.4) to enter the second chamber (1.3), the horizontal pipe has a valve (K1) to regulate flow of wastewater from the first chamber (1.2) to the second chamber (1.3);
- an overflow pipe (1.10) is connected to the vertical pipe (1.8) at a height of nearly equal to height of the water inlet pipe of the first chamber (1.2), and passes through the divider wall (1.4) to enter the second chamber (1.3);
- the second chamber (1.3) contains the biological beds (1.6) in a fourth region (V4) on a support frame (1.7), wherein the support frame (1.7) itself is an air duct for conveying air from an air blower to supply air to the biological beds (1.6) in the second chamber (1.3) through valves (K5 and K6) and diffusers located in lower part of the support frame (1.7);
- a fifth region (V5) located beneath said fourth region (V4) to store clean water which has been treated and sediment;
- a vertical pipe (1.14) passes through the biological beds (1.6) and has a lower end connected to the fifth region (V5) and an upper end at a height equal to the height of the upper end of the vertical pipe (1.8), the vertical pipe (1.14) is connected to a discharge tank (B) via a horizontal pipe (1.15) which has a one way valve (K2) to discharge treated clean water out through the discharge tank (B);
- an overflow pipe (1.16) connects the vertical pipe (1.14) to the discharge tank (B) at a height equal to the height of the overflow pipe (1.10);
- a biological safety pipe (1.11) connects the vertical pipe (1.8) to the discharge tank (B) at a position lower than the horizontal pipes (1.9) and (1.15) to directly discharge water from the vertical pipe (1.8) out through the discharge tank (B);
- a return pipe (1.12) has one end connected to the mixing chamber (A) and another end connected to an end part of the fifth region (V5) and is connected to an air blower (1.13) to receive compressed air from the air blower to pump a part of clean water from the fifth region (V5) through the return pipe (1.12) for returning to the mixing chamber A and supplying clean water to the water sprayer (R) located in the upper region (V1) to wash the garbage.