Country :South Africa
Product: 50NM, Modulating dc24v, 200pc electric actuators MTD
Application case: Chlorine Scrubber at a Water Treatment Plant.
How to treat municipal sewage? And why we need do water treatment
In the continued world population growth and accelerated urbanization, the provision of drinking water and sanitation remains a critical issue for many cities, especially those in developing countries. Sanitation is the umbrella term for all technologies used to collect, transport and treat wastewater before it can be discharged into the natural environment. It can be planned and designed on the scale of an urban area (i.e. centralized sanitation) or conceived on the scale of a residential dwelling, i.e. not connected to a centralized sewer network (i.e. free-standing sanitation). There is a trend that the sewage treatment plants of the future will become real sewage treatment plants, where green energy, fertilizers and precious metals can be produced and the treated sewage can be reused.
Application of chlorine dioxide
1. Disinfection of tap water
The most important feature of chlorine dioxide is that it can reduce the concentration of total halomethanes in tap water. Generally, the amount added to natural water is 2.0 mg/L. It can kill f 2 bacteriophage in water for 1 minute, and the number of Escherichia coli can reach drinking water for 3 minutes. Standard. In the early 1980s, more than 100 drinking water treatment plants in the United States have used stable ClO 2 for disinfection and sterilization to remove color and odor in water; Canada also has more than 10 similar water plants, and this water treatment system has been rising in Europe. my country Chlorine dioxide has been developed for drinking water disinfection, and good results have been achieved.
2. Swimming pool water disinfection and water quality stability
Chlorine dioxide has a good disinfection effect on swimming pool water. If its content reaches 0.5mg/L, the total number of bacteria will be reduced from 3.4×10 3 /ml to 3/ml. Escherichia coli will be reduced from 70/L to undetected. It is in full compliance with the national water quality standards for swimming pools. The groundwater used in a swimming pool in Chengdu becomes muddy within three days. Adding 0.5ppm of chlorine dioxide can stabilize the water quality for more than half a month.
Industrial Wastewater Treatment
3. Industrial wastewater often contains many harmful substances, such as cyanides, sulfides, phenols and amines, which must be treated before they can be discharged. In the pH range of 5~9, an average of 5.2 parts of chlorine dioxide can convert a part of sulfide. The ions are rapidly oxidized to sulfate ions. At different pH values, chlorine dioxide can oxidize CN— to cyanate or carbon dioxide and nitrogen, for example, an average of 2.5 parts by mass of chlorine dioxide can convert 1 part by mass of simple cyanide Oxidation into cyanate. Above pH10, an average of 5.5 parts of chlorine dioxide can oxidize 1 part of cyanide to carbon dioxide and nitrogen. Generally, 1.5 parts of chlorine dioxide can oxidize 1 part of phenol to benzene. Quinone, when the pH is 10, an average of 3.3 parts by mass of chlorine dioxide can oxidize 1 part by mass of phenol to a mixture of low molecular weight non-aromatic carboxylates. Chlorine dioxide can also remove organic amines and organic sulfur compounds. The resulting odor.
Recycled Sewage Reuse
Many parts of the world face seasonal and even perennial water shortages, and treated sewage can be reused to make up for water shortages. They can be used to irrigate green spaces and golf courses, irrigate agricultural areas, meet industrial water needs or produce potable water (directly for potable water production, or indirectly for potable water production by replenishing reservoirs or infiltration into groundwater bodies ). Depending on the purpose of the wastewater reuse, the wastewater needs to undergo appropriate post-treatment after being treated in a treatment plant, ranging from simple disinfection to a far more complex series of treatments.
Notice:
Wastewater treatment was initially intended for sanitation and resident health protection in large cities, and then expanded to meet stricter discharge standards in the 1970s to protect the natural environment.
The urban sewage is treated by biological method, supplemented by physicochemical method to remove phosphorus. Industrial wastewater is treated separately in specific installations.
In urban areas with more than 2,000 to 4,000 inhabitants, intensive wastewater treatment plants mainly use the activated sludge process (90% of municipal wastewater in France is collected and treated).
For small communities, extensive use natural lagoon methods or reed filters.
Ongoing technological development for waste water treatment plants is currently focused on the utilization of waste water treatment plants sludge, including the recovery of energy in the form of biogas or thermal energy, as well as the production of fertilizers or bioplastics, and sometimes the recovery of metals extracted from them.
