| 摘要 |
Biomass with high nitrogen and phosphorus content is produced by (a) forming a mixed liquid by mixing activated biomass with nitrogen-, phosphorus- and BOD-contg. feed under anaerobic conditions so that it is essentially free from NOx- and has a dissolved oxygen content of 0.7ppm. by which means there is effected a selective prodn. of non-filamentous microorganisms which are capable of sorbing BOD under anaerobic conditions. Process further comprises (b) oxidising BOD in the mixed liquid by contacting with O2-contg. gas under conditions such that a dissolved oxygen content of is not 1 ppm. is maintained; (c) allowing the oxidised mixed liquid to settle in order to separate a supernatant liq. from a denser biomass; (d) using a part of the sepd. biomass as activated biomass for mixing with further BOD-contg. feed1 and (e) recovery of the remainder of the settled and sepd. biomass as the prod. The biomass produced can be used as fertiliser, as an animal feedstuff or as a high-energy biomass for the fermentation industry. when used as a fertiliser, the biomass is particularly advantageous, since both the phosphorus and the fixed nitrogen content are available to plants; since the nitrogen is mainly in the form of protein and the phosphorus is largely in the form of plyphosphate, the prod. has slow-release properties. |
