Influence of Temperature, Agitation, Sludge Concentration and Solids Retention Time on Primary Sludge Fermentation
Table 1
Requirements for discharges from urban waste water treatment plants to sensitive areas which are subject to eutrophication. Council directive of 21 May 1991 concerning urban waste water treatment (91/271/EEC).
Parameters
Concentration
Minimun percentage of reduction
Reference method of measurement
Total phosphorus
2 mg/L (10,000–100,000 p.e.)1 mg/L (more than 100,000 p.e.)
80
Molecular absorption spectrophotometry
Total nitrogen
15 mg/L (10,000–100,000 p.e.)10 mg/L (more than 100,000 p.e.)
