How to reduce COD in wastewater?

In the context of rapid economic development, the impact of environmental pollution is becoming increasingly serious. The water pollution caused by sewage discharge is the most direct and serious consequence because it is related to the life safety and quality of life of people. Therefore, it is very important to reduce the discharge of harmful substances in wastewater and increase the utilization rate of recyclable wastewater. So, how to reduce COD in wastewater?

 

1. What is COD?

Chemical oxygen demand (COD) is a chemical method to measure the amount of reducing substances that need to be oxidized in water samples, which is often expressed by the symbol cod. Cod is expressed in mg / L. COD values detected by water quality monitoring instruments can be divided into five categories. Among them, COD of the first and second categories is less than 15mg / L, which basically meets the drinking water standard. The remaining three COD values can not be used as drinking water. The third type of COD ≤ 20mg / L, the fourth type of COD ≤ 30mg / L, and the fifth type of COD ≤ 40mg / L belong to the polluted water quality. The higher the COD value is, the more serious the pollution is.

 

2. The importance of COD

Chemical oxygen demand (COD) is an important organic pollution parameter which can be determined quickly in the study of river pollution and industrial wastewater properties and the operation and management of wastewater treatment plants. It reflects the degree of water pollution by reducing substances. The higher the COD is, the more serious the pollution of organic matter is.

 

3. What is the measurement method of COD in wastewater?

<1> Dichromate reflux method

Advantages: classical standard method, Good reproducibility,Accurate and reliable.

Disadvantages: the reflux device takes up a large amount of experimental space; The consumption of water and electricity is large; Because of the large amount of reagent and inconvenient operation, it is difficult to determine in large quantities.

Determination principle: In the acidic medium of sulfuric acid, potassium dichromate was used as the oxidant, silver sulfate as the catalyst, and mercury sulfate as the masking agent of chloride ion. The sulfuric acid acidity of the digestion reaction solution was 9 mol / L, and the digestion reaction solution was boiled by heating. The boiling point temperature of 148 °C ± 2 °C was the digestion temperature.  The residual potassium dichromate was titrated by ammonium ferrous sulfate solution after water cooling reflux heating reaction for 2 h, and the digestion solution was cooled naturally. The COD value of the water sample was calculated according to the consumption of ammonium ferrous sulfate solution.

 

How to reduce COD in wastewater?

评论

发表评论

此博客中的热门博文

What is Activated Carbon

图片
Activated carbon is one of the most common adsorption media   used on filters to control indoor air quality and reduce pollutants. The popularity of activated carbon is due to its inherent ability to adsorb most organic chemicals due to the large surface area created by the increased activation on the carbon/charcoal surface. When it comes to the capture and control of gaseous compounds present in the indoor air space, activated carbon will quickly and effectively trap these contaminants on this activated filter media. In some cases, the charcoal/carbon material will be treated with additional chemicals during the activation of this material, which will be done through the use of a chemical called potassium permanganate. Potassium permanganate is used in activated carbon filter media to help attract reactions between the carbon media and the oxidation of polar or low molecular weight compounds. In addition, many manufacturers use this chemical additive on carbon filters to help extend
阅读全文

Waste Carbon Recovery for Environmental Sustainability

图片
Used granular (GAC) or extruded (EAC) activated carbon can be recycled through thermal activation, which involves treating the used carbon in a high temperature activation oven at 850°C or above. Recovery by thermal regeneration is only one of the steps in the complete service package. The recovery process consists of two main processes: 1) reactivation process and 2) tail gas treatment and energy recovery process.     The reactivation process itself can be subdivided into four steps. 1) Drying of used carbon The used carbon is fed into the furnace and heated from ambient temperature to 105 - 110°C. Water and some low boiling compounds are evaporated and released into the furnace atmosphere. As long as there is water in the pores,  the temperature of the carbon  remains between 105 and 110°C. 2) Desorption of low boiling point organics. As the carbon dries, the temperature increases further to about 450°C. During this temperature increase, various organic compounds are desorbed from th
阅读全文

Welcome to Zhengzhou Yihang Water Purification Materials Co., Ltd

图片
Zhengzhou Yihang Water Purification Materials Co., Ltd.  was established in 2014 and is located in Zhengzhou, Henan Province, enjoying convenient transportation and beautiful environment. Our factories covers an area of 400 square meters and has 100 employees. As a activated carbon manufacturer , we are specialized in activated carbon  for nearly 20 years . Our company has rich experience in the water and waste gas purification industry. Our main products include  pellet activated carbon , granular activated carbon , powdered activated carbon , honeycomb activated carbon , mainly used for water purification, air purification, gold smelting, food and drug industry, etc. We are making great efforts to develop new products to meet different requirements. Our company has Electronic balance scale, Compressive strength tester, One smart muffle furnace, Automatic calorimeter equipment to strictly control the product quality. Adhering to the business principle of mutual benefits, we have had a
阅读全文