New technologies for waste gas treatment include biological processes, oxidation processes and combined purification processes.The combined purification process was emphatically discussed.Biological method mainly deals with low concentration and large amount of hydrogen sulfide waste gas;Oxidation method mainly deals with high concentration hydrogen sulfide waste gas, which needs to recycle resources.The combined purification technology has a good adaptability to the concentration and gas fluctuation of hydrogen sulfide exhaust gas, and nano photocatalysis and other new technologies have a broad development prospect.

The results show that the purification performance of biofilm packed tower is better than that of sieve plate tower and bubble tower, and the purification efficiency of low concentration toluene waste gas can be kept above 90%.The liquid-gas ratio is 0.03 ~ 0.1.

Under the condition of gas velocity of (30 ~ 60) m·h, the waste gas treatment biofilm packed tower has the same purification effect on toluene homologues in the waste gas, and has a better purification effect on the actual production waste gas of recycling rubber factory, printing factory, foundry, paint factory and so on.The separation and recovery of CO2 from industrial waste gas, application of CO2 gas fertilizer and CO2 modified fruit and vegetable freshness preservation have good economic and environmental benefits.

Therefore, it is of great significance to further study and popularize the technology of waste gas treatment.Reasonable selection of dust collector can not only ensure the dust removal efficiency required by the emission standard of waste gas treatment, but also form the most economical dust removal system.In recent years, with the rapid development of dust removal technology, dust removal efficiency has also been significantly improved, especially electrostatic dust removal and bag dust removal.

Therefore, waste treatment is mostly used in some projects with the largest dust (powder) emissions and mainly air pollution, such as large thermal power plants.And its efficiency is generally more than 99%, because of its high efficiency of waste gas treatment, simple operation and widely used.In addition to bag dust collector, electrostatic precipitator has been widely used because of its advantages such as economy.

Electrostatic precipitator is a kind of dust removal equipment.It electrifies the dust gas in the ionization process through a high-voltage power station.Under the action of the electric field force, the dust particles are deposited on the dust remover, and the dust particles are separated from the dust-containing gas.The fundamental difference between it and other exhaust gas treatment and dust removal processes is that the separation force (mainly electrostatic force) acts on the particles rather than the whole airflow, which determines that it has the characteristics of low energy consumption and small airflow resistance.

The main advantages of electrostatic precipitator in waste gas treatment are: small pressure loss, high dust removal efficiency, up to 99%, can work in high temperature or strongly corrosive gases.