1) Using predation of micro- metazoa to reduce excess sludge production in wastewater treatment system is praised an eco-technology of sludge reduction with low-power and no-secondary pollution.

2) The tubificidae, one type of metazoa was chosen to control activated sludge bulking which was caused by filamentous bacteria.

3) The late Neoproterozoic is an important period of biological evolution; and the emergence of metazoa is a representative event, which marked the history of biology evolution having entered a new era.

4) The biofilm microscopic observed results indicated that biofacies were quite rich in the biofilm, including all kinds of bacteria, fungus rubber group, protozoa, metazoa and so on.

5) Owing to its distinct attribute property and old age, this discovery may have epoch—making significance on the study of the evolution of early Metazoa.

6) The paper mentions the wastewater treatment process fitting for growth of micro - metazoa and sludge reduction emphatically.