Most water sources in my country have relatively low raw water quality, serious pollution, high water turbidity, chroma, and organic concentration; due to the long-term lack of sewage treatment facilities, coupled with large project investment and high operating and management costs, it will be quite long in the future During this period, the purification of micro-polluted water (water containing trace pollutants) will be an important research topic. The current scientific and technological issues restricting the field of drinking water treatment can be summarized into the following aspects:
(1) Process theory and technology for removing trace organic pollutants in water;
(2) Enhanced treatment technology of algae and its metabolites (odor, algae toxin, etc.) in water;
(3) Removal and control technology of by-products in water treatment process;
(4) Enhanced technology for conventional water treatment;
(5) High-efficiency disinfection technology, etc.
Trace organic pollutants in drinking water are harmful to the human body, but they are difficult to remove. Especially high-stability soluble organic pollutants, such as halogenated organics, nitro compounds, polycyclic aromatic hydrocarbons, etc., are more harmful to the human body. Traditional water treatment processes have limited removal effects on these organic micro-pollutants, and there is an urgent need to research and develop cost-effective micro-pollutant removal technologies.
Algae in water are generally negatively charged, have high stability, are difficult to coagulate, and seriously affect the effect of water treatment; the specific gravity of algae is small, and the precipitation effect is poor; the algae produce a variety of odors during metabolism, which directly affect the sensory properties of water Influence; some algae are very small in size and can penetrate the filter and enter the water supply pipe network, affecting the water quality in the pipe network; algae are typical precursors of chlorinated disinfection by-products, which can react with chlorine in the subsequent disinfection process Harmful by-products increase the mutagenic activity of water; certain algae (such as cyanobacteria) can produce algae toxins, posing a threat to humans and animals, and some of them are hepatic toxins and neurotoxins. In addition, algae will adhere to the surface of the filter material, which significantly shortens the filter cycle of the filter, causing frequent backwashing of the filter;
The organic components have a serious protective effect on the colloid, which affects the coagulation effect, resulting in a significant increase in drug consumption and an increase in the residual concentration of aluminum in the water.
Some by-products introduced in the water treatment process (such as monomers in polyacrylamide, etc.) will also have an adverse effect on drinking water quality. A variety of halogenated organic by-products produced in the process of chlorination and disinfection are more harmful to the human body and are the by-products of key control in drinking water. Especially in the traditional pre-chlorination process, the high concentration of chlorine directly interacts with the higher concentration of organic pollutants in the raw water, resulting in a higher concentration of chlorinated disinfection by-products.
Disinfection has always been the most important link in water supply treatment. Poor disinfection effect will cause epidemic outbreaks, especially the inactivation of pathogenic protozoa such as beetles and cryptosporidium, which is a key issue in current disinfection technology research.
Generally, the investment in decontamination process equipment is relatively large. Due to financial constraints, it is difficult to use expensive decontamination processes on a large scale. This is also the main reason for the low quality of drinking water in my country.