2, urban sewage treatment plant leading technology review
1) AB process
AB method by the German first Professor BOHUKE development. The process of the aeration tank is divided into high and low load two, each with independent precipitation and sludge return system. High-load section (A) residence time of about 20 - 40 minutes to bio-flocculation adsorption mainly at the same time the occurrence of incomplete oxidation, biological mainly for the short generation of bacterial communities, remove BOD more than 50%. The B section is similar to the conventional activated sludge process and has a low load and a longer mud age.
AB method A section of high efficiency, and a strong buffer capacity. B section to play the role of water gate, the treatment stability is better. For high concentrations of sewage treatment, AB method has a good applicability, and a higher energy efficiency. Especially in the use of sludge digestion and biogas utilization process, the most obvious advantages.
However, AB sewage sludge production, A section of sludge organic matter content is very high, sludge subsequent stabilization treatment is necessary, will increase the investment and cost. In addition, because the A section to remove more BOD, may cause the lack of carbon source, it is difficult to achieve denitrification process. For the low concentration of sewage occasions, B section is more difficult to run, it is difficult to play advantage.
There is only a paragraph of the practice, the effect is better than a level of treatment, as a transition process, the performance and price ratio has a better advantage. Generally applicable to row river, row of sea occasions.