Removal of Organic Pollutants from High Turbidity Water in Yellow River by Polymer Flocculant

In recent years, with the rapid development of the industrial and agricultural economy, the organic pollution of the Yellow River water quality has also developed to a worrying point, especially for the urban water supply system, the conventional treatment methods to remove the role of organic pollution Very small, and the subsequent chlorination added the formation of halogenated hydrocarbon carcinogens. According to related data, the organic matter content of the Yellow River water is related to the sediment content of the Yellow River to some extent. According to a large number of related reports, the water quality of the Yellow River has been deteriorating, and the water quality in some areas has exceeded the Grade 5 standard for water sources.

According to relevant foreign data, the use of cationic polymer flocculants in combination with polymeric aluminum can remove up to 90% of dissolved organic contaminants in source water. 2. Reinforce and utilize existing treatment processes to remove organic contaminants from water as much as possible. In order to protect the people's health, it is in line with China's national conditions and economical and effective methods and approaches. The cost of cationic polymer flocculants is higher than that of anions. We chose the latter as a reagent for production tests and conducted a productive study on the removal of organic contaminants in water by polymer flocculants.

1 Water treatment process and analysis method 1.1 Water treatment process (see) Anionic polymer flocculant Polymerization of aluminum Yellow River water 1> Pre-settlement pond 4 Second sedimentation pond water plant 1.2 Pharmacy dosage According to water quality, anionic polymer flocculant AN910PWG Dosage control in the 0. 1 ~ 0.5mg / L, the amount of polymerization of aluminum control 1.3 Analysis Method Sampling: The sampling point is set in the pre-settlement tank and before leaving the factory. After sampling, the supernatant was collected for 30 min to analyze the potassium permanganate oxygen consumption.

Analysis: The analysis of sediment content in water adopts the oxygen demand CODMn analysis recommended by the Yellow River Management Committee and adopts GB5750 method.

2 Results and discussion After one year of observation, adjustment and analysis, we will treat the Yellow River water from the pre-settlement tank of a water plant and pipe it to a second water plant about 2 km away for secondary treatment, and then add chlorine to sterilize the plant. . Before the pre-sinking tank, we use anionic polymer flocculant produced by French SNF company as a pre-sinking agent. The total amount of water is 250,000 m3/d. The effluent turbidity of a water plant is usually controlled at 50, which is consistent with the report. In their report, it was pointed out that the content of organic matter in the sediment of the Yellow River was 1.07%, and the available phosphorus content was about 20mg/L. However, from September onwards, although the sediment content of the Yellow River decreased, the oxygen demand of potassium permanganate in the Jinan section continued to increase. This phenomenon may be due to the decrease in the flow of the Yellow River. After the summer peak flow, it brought a lot of industrial and agricultural pollution. Material, but due to the flow of water to the drain water uill.26Nmic amount decreased, resulting in increased concentration of pollution. It may also be caused by the fact that the upper five small-scale industries continue to violate the law. This phenomenon needs further observation.

However, we found interesting results from the results of the sum. First, although the CODMn of the raw water changed, even the monthly average CODMn was as high as 35 mg/L, but the CODMn of the effluent was kept below 3 mg/L. At the time, we were very pleased to see that the monthly average removal rate of CODn was around 75%, and the lowest was about 52% and the highest was over 90%. This result is consistent with the international research findings and views. In addition, we also noticed that the higher the sediment content in the raw water, the higher the CODMn removal rate. We believe that the sediment of the Yellow River has a large amount of organic matter adsorbed on the surface. When an anionic polymer flocculant is used as a coagulant for sedimentation, on the one hand, it contributes to the rapid sedimentation of sediment, and on the other hand, due to the polymer Adsorption of long chain and its amide groups with organics also removes organic matter during sedimentation.

The anionic polymer flocculant we use has a high molecular weight, but its ionization degree is relatively low, because the amide group (CONH2) rather than the hydroxy acid group (COO-) can be used to absorb the amide groups in the water. Combined with the high molecular weight, it can effectively remove organic macromolecules in water.

3 Conclusions Through one year of research and observations, organic matter in the Yellow River water is mostly adsorbed on the surface of sediment particles, so organic pollutants are also removed while removing sediment.

The removal of organic matter is related to the selection and treatment of polymer flocculants. Due to the selection of high molecular weight, high amide-based flocculants, the adsorption rate of organics in water is greatly improved.

We believe that the removal of organic matter is mainly realized in a water plant. This is because in the Yellow River water plant of the same type, no prepolymerized flocculant has been added to the pre-sedimentation tank. The follow-up process is the same as that of the second water plant, and COD The removal rate is quite limited.