Waste water treatment by slag

With the use of slag coal as partitions in septic tanks, the efficiency of waste water treatment tanks is significantly improved with low cost. This is the solution of Dr. Nguyen Viet Anh, Hanoi University of Construction.

Improved filter tank of Dr. Viet Anh.(Photo: Planning and Planning)

The research team of Dr. Viet Anh has successfully improved the traditional septic tanks by changing the structure of the tank, adding thin walls with vertical flow in the tank. Under this procedure, the wastewater does not pass through the tank horizontally but moves from the bottom to the top, going through the bottom mud layer. The anaerobic bacteria have a lot in the bottom sediment layer that will absorb and decompose organic matter in waste water. The partitions also allow to increase the coefficient using tank volume, avoiding dead water areas.

The anaerobic filter is arranged at the end of the tank, further filtering the suspended and organic substances in the waste water. The outlet wastewater is treated by a filter plant for growing aquatic plants. Therefore, the quality of treated water always meets environmental standards.

Dr. Nguyen Viet Anh said, tank volume depends on demand. This type of tank is suitable for domestic wastewater treatment for each household and for residential areas with 25-50 households.

Household treatment tank Ms. Nguyen Thi Thanh (Kim Nguu, Hanoi) has a capacity of 3m3 (designed for 5-person households) including a settling compartment, two up-flow compartments and two serial anaerobic compartments. The above design will reduce the rate of sludge accumulation in the settling chamber. The ventilation pipe avoids the formation of thick scum on the tank surface and sludge in anaerobic filters. Here, the anaerobic filtration does not play a significant role in biological treatment but mainly to avoid solids washing.

Households only need to build a one-compartment tank and two compartments with upward flow. Also the anaerobic filter should only be applied in case the tank is built outside the house, serving crowded people, because the filter compartment allows separation of sediments, avoiding clogging in the process of dispersing waste water, so maintenance and Clean it.

Not only is the household applied, this type of tank is being implemented a lot in craft villages such as vermicelli vermicelli village of Tan Hao (Ha Tay), Tam Da wine-making village (Bac Ninh).