3. Results and discussion
3.1. Z08 soybean wastewater treatment
The soybean wastewater COD decreased by 95.7% after 168 h treatment by Z08 without extra light or oxygen provision (Fig. 1). The pH rose slightly from 6.5 to 8.2, which was suitable for PSB growth. The results showed that Z08 could treat soybean wastewater
under natural conditions. That was very different from the traditional processes in which extra light or oxygen was supplied to insure PSB growth. So this technique could save energy compare with conventional PSB methods.