[Growth kinetics of aquatic worms feeding on activated sludge]

The growth kinetics of aquatic worms was investigated from juvenile to decline phase for 18 weeks by cultivating with activated sludge in batch test. Results showed that the growth of aquatic worms well fit Gauss function for cultivating 18 weeks. The maximum specific growth rate, growth yield of aquatic worms and sludge reduction rate was 0.41 d(-1), 0.32 and 25.5%, respectively. When the concentration of substrate and dissolved oxygen change from low to high, the relationship between the specific growth rate with dissolved oxygen, and substrate concentration meet the Monod equation. Compared with the dissolved oxygen, the substrate concentration had greater effect on the specific growth rate of aquatic worms, and aquatic worms can live in the environment with low dissolved oxygen. Furthermore, the breath test showed the oxygen uptake rate of aquatic worms was almost 6.39, 10.10, 11.31 and 5.74 mg x (L x g x h)(-1) from juvenile to decline phase, the dissolved oxygen demand of the rapid growth and mature stage was higher than juvenile and decline phase.