Natural Treatment Systems as Sustainable Ecotechnologies for the Developing Countries

Table 5

Total annual energy for typical 1 mgd system including electrical plus fuel, expressed as 1000 kwh/yr [180].

Treatment system	Energy (1000 KwH/yr)
Rapid infiltration (facultative pond)	150
Slow rate, ridge, and furrow (facultative pond)	181
Overland flow (facultative pond)	226
Facultative pond + intermittent sand filter	241
Facultative pond + microscreens	281
Aerated pond + intermittent sand filter	506
Extended aeration + sludge drying	683
Extended aeration + intermittent sand filter	708
Trickling filter + anaerobic digestion	783
RBC + anaerobic digestion	794
Trickling filter + gravity filtration	805
Trickling filter + N removal + filter	838
Activated sludge + anaerobic digestion	889
Activated sludge + anaerobic digestion + filter	911
Activated sludge + nitrification + filter	1051
Activated sludge + sludge incineration	1440
Activated sludge + AWT	3809
Physical chemical advanced secondary	4464

These energy requirements were reported for meeting the four effluent quality standards, that is, BOD₅, TSS, P, and N.