Wastewater treatment plays a crucial role in protecting the environment and human health

Wastewater Treatment va cach xu ly nuoc thai

Wastewater Treatment: Wastewater generated during the production process is an issue that impacts the operation of businesses. Treating this wastewater is a challenging and often costly problem for companies.

Wastewater Treatment using Ionization Technology: We apply new and advanced technology to address pollution issues, meeting the criteria of low cost, simple installation, and operation, as well as low operational and maintenance costs.

Ion Exchange Technology in Wastewater Treatment Process

Ion Exchange Technology: Ion exchange devices generate a large number of free ions in the water, which act vigorously. These ions break down the bonds of organic compounds, react with inorganic compounds and heavy metals in the water, causing them to precipitate completely without the need for chemicals.

The ion environment alters the properties of water, providing high bactericidal capabilities that help eliminate bacteria and pathogens present in the water. This reduces the need for disinfecting chemicals, thus saving operational costs and minimizing chemical residues after treatment.

Main steps and technologies in wastewater treatment process Xu ly nuoc thai det nhom

Preliminary Treatment

Screening: Removal of large objects such as leaves, plastic waste, metals, paper, etc.

Grit Chamber: Removal of sand, gravel, and other heavy particles.

Equalization Basin: Adjusting the flow rate and pollutant concentration in the wastewater.

Primary Treatment

Primary Clarifier: Removal of suspended solids by settling to the bottom of the tank.

Oil and Grease Removal: Methods such as skimming, and membrane filtration are used to remove oils and greases.

Secondary Treatment

Biological Treatment: Use of microorganisms to decompose organic matter. Common systems include:

Aerotank: A system that uses oxygen to enhance the activity of microorganisms.

UASB (Upflow Anaerobic Sludge Blanket): Anaerobic treatment, using microorganisms to decompose organic matter without oxygen.

MBR (Membrane Bioreactor): Combining biological treatment and membrane filtration.

Tertiary Treatment

Chemical Treatment: Use of chemicals to precipitate and remove remaining pollutants.

Filtration: Methods such as sand filtration, and activated carbon filtration to remove small particles.

Disinfection: Methods such as chlorine, ozone, and UV are used to kill pathogenic microorganisms.

Sludge Treatment

Sludge Thickening: Increasing sludge concentration by water separation.

Sludge Treatment: Methods such as fermentation, drying, and incineration to treat sludge.

New Technologies and Development Trends

Membrane Technology: Use of membrane filtration to remove pollutants with high efficiency.

Phytoremediation: Use of plants to absorb and remove pollutants.

Advanced Microbial Treatment: Use of selected microbial strains to enhance treatment efficiency.

HOW DO CITIES TREAT WASTEWATER, TO MAKE IT SAFE FOR DISCHARGE?

There are several levels of wastewater treatment; these are primary, secondary and tertiary levels of treatment. Most municipal wastewater treatment facilities use primary and secondary levels of treatment, and some also use tertiary treatments. The type and order of treatment may vary from one treatment plant to another, but this diagram of the Ottawa-Carleton wastewater treatment plant illustrates the basic components.

The primary level of treatment uses screens and settling tanks to remove the majority of solids. This step is extremely important, because solids make up approximately 35 percent of the pollutants that must be removed. The screens usually have openings of about 10 millimetres, which is small enough to remove sticks, garbage and other large materials from the wastewater. This material is removed and disposed of at the landfill.

The water is then put into settling tanks (or clarifiers), where it sits for several hours, allowing the sludge to settle and a scum to form on the top. The scum is then skimmed off the top, the sludge is removed from the bottom, and the partially treated wastewater moves on to the secondary treatment level. The primary treatment generally removes up to 50 percent of the Biological Oxygen Demand (BOD; these are substances that use up the oxygen in the water), around 90 percent of suspended solids, and up to 55 percent of fecal coliforms. While primary treatment removes a significant amount of harmful substances from wastewater, it is not enough to ensure that all harmful pollutants have been removed.

Secondary treatment of wastewater uses bacteria to digest the remaining pollutants. This is accomplished by forcefully mixing the wastewater with bacteria and oxygen. The oxygen helps the bacteria to digest the pollutants faster. The water is then taken to settling tanks where the sludge again settles, leaving the water 90 to 95 percent free of pollutants. The picture below shows the settling tanks in the Winnipeg Wastewater Treatment Plant. Secondary treatment removes about 85 to 90 percent of BOD and suspended solid, and about 90 to 99 percent of coliform bacteria.

Some treatment plants follow this with a sand filter, to remove additional pollutants. The water is then disinfected with chlorine, ozone, or ultraviolet light, and then discharged. For more information about any of the steps of the water treatment process.

The sludge that is removed from the settling tanks and the scum that is skimmed off the top during the primary steps are treated separately from the water. Anaerobic bacteria (anaerobic bacteria do not require oxygen) feed off of the sludge for 10 to 20 days at temperatures around 38 degrees Celsius. This process decreases the odour and organic matter of the sludge, and creates a highly combustible gas of methane and carbon dioxide, which can be used as fuel to heat the treatment plant. Finally, the sludge is sent to a centrifuge, like the one shown in the picture below. A centrifuge is a machine that spins very quickly, forcing the liquid to separate from the solid. The liquid can then be processed with the wastewater and the solid is used as fertilizer on fields.

Tertiary (or advanced) treatment removes dissolved substances, such as colour, metals, organic chemicals and nutrients like phosphorus and nitrogen. There are a number of physical, chemical and biological treatment processes that are used for tertiary treatment. One of the biological treatment processes is called Biological Nutrient Removal (BNR). This diagram shows the treatment steps that Saskatoon wastewater goes through.

In this treatment plant, wastewater first undergoes primary and secondary treatment. For the tertiary treatment, the BNR process occurs in the bioreactors. The BNR process uses bacteria in different conditions in several tanks, to digest the contaminants in the water. The three tanks have unique environments, with different amounts of oxygen. As the water has passes through the three tanks, the phosphorus is removed and the ammonia is broken down into nitrate and nitrogen gas, which other bacterial processes can not do. The BNR process can remove over 90 percent of phosphates, while traditional processes remove much less than 90 percent. The water spends approximately nine hours in the bioreactors, before entering the secondary clarifier, which is a settling tank, where the bacteria-laden sludge settles to the bottom of the tank.