He said that it is necessary to encourage or to force the subjects which use much water, to use recycled water, and if so, the demand for recycled water may reach 1.5 million cubic meters per day.
Using recycled water will help HCM City save money and reduce the overspending, while it would be able to control the water sources to be used in dry season, and ease the reliance on the water sources from water reservoirs, minimize the pollution.
Of the subjects that need to use recycled water, the demand from civil activities and irrigation is believed to account for a big proportion. Besides, recycled water would also bee needed to regenerate the landscapes, such as putting the river flow through, restore the water resources for the polluted river and canal systems and create urban landscapes
One of the most important purposes of the plan on using recycled waste is to ensure the health of the community. Therefore, the recycled waste water needs to be treated to meet the standards of reducing or eliminating pathogenic bacteria, parasites, intestinal virus in recycled water, the composition of the hazardous chemicals in recycled water.
Recycled waste water can be safe for health
Dr Dan, leader of the research team, said that the water recycling technology chosen for consideration is the processing technology with biological activated carbon (BAC) and bio-sand filter (BSF). A model with the testing scale of 2 cubic meter per day has been installed at the Binh Hung Hoa waste water treatment station in Tan Phu district of HCM City.
After the experiencing period, scientists have decided to choose the 2-3 m/h filtration speed for BAC-BSF technology as the solution for recycling waste water, which brings relatively good effects, while the process of nitrification and nitrate reduction can go well.
The research work has brought the results which can meet the standard quality, in accordance with the regulations of the World Health Organization WHO.
According to scientists, users can choose to use recycled water based on their demand. Recycled waste water can be divided into three grades, low, medium and high. The low and medium grade recycled water can be used for watering plants, serving at parks, cleaning industrial machines, cleaning toilets, distinguishing fire, watering the roads. The costs prove to be reasonable to the purposes of use, at 4000 dong per cubic meter.
The research work by the team from the HCM City University of Technology has been highly appreciated by scientists.
“In HCM City, the recycling and reusing of waste water after treatment for different purposes has been considered and developed in the first stage to clarify the scientific foundation and the possibility of applying the research in reality. The research work of the scientists from the HCM City University of Technology has affirmed this,” said Professor Dr Lam Minh Triet, Head of the Institute of Water and Environmental Technology, vice president of Nature and Environment Protection of Vietnam - VACNE).