Organic toxic pollutants are mainly the following categories:
(1) organic pesticides, PCBs. Organic pesticides can be divided into organophosphorus pesticides and organochlorine pesticides. Organophosphorus pesticides, although highly toxic, but generally easy to degrade, accumulation is not strong, so the impact on the ecosystem is not obvious; while the vast majority of organochlorine pesticides, toxicity, virtually non-degradable, accumulation is very high, the ecosystem has a significant impact. Polychlorinated biphenyl (PCB) is a general term for a mixture of isomers formed when part or all of the hydrogen in the biphenyl molecule is replaced by chlorine.
(2) Carcinogens. Carcinogenic substances are divided into three categories: thick ring aromatic hydrocarbons, such as benzopyrene, etc.; heterocyclic compounds, such as aflatoxin, etc.; aromatic amines, such as methyl, ethyl aniline, benzidine and so on.
(3) general organic substances. For example, there are thousands of phenolic compounds, the simplest one is phenol, which is highly toxic; nitrile compounds are also toxic, among which acrylonitrile has the most important environmental impact.
(4) Petroleum pollutants. Petroleum is a mixture of alkanes, olefins and aromatic hydrocarbons, and the hazards of entering water bodies are manifold.
For organic pollution in wastewater less use of coagulants such as polymerized ferric sulfate and other coagulants on the period of mixed precipitation removal,