Table 4: Performance comparison of UASB with other wastewater treatment technologies.

Sr. numberParameterUASBActivated Sludge Process (ASP)Trickling Filters (TF)Waste stabilization pond (WSP)Moving Bed Bioreactor (MBBR)References

(1)BOD removal, %75–8385–9080–9075–8585–95[10, 62, 92, 9598]
(2)COD removal, %70–8080–9585–9070–8585–90[10, 44, 62, 92, 95100]
(3)TSS removal, %70–8085–9075–8570–8585–95[10, 62, 92, 9597]
(4)Overall HRT4–10 hrs12–14 hrs13-14 hrs8–15 days8–12 hrs[49]
(5)Average applied OLR for sewage treatment1.0–2.0 KgCOD/m3·day0.3–0.55 KgBOD/m3·day1.5 to 2.0 KgCOD/m3·day50–450 kgBOD/ha·d4–30 gCOD/m2·day[11, 20, 31, 42, 49, 101106]
(6)Average area required (m2/mld)1450182016208000450[62]
(7)Biogas generation0.05–0.25 (m3/Kg COD removed)NilNil0.05 to 1.5 m3/Kg BOD5 removed (not usually collected)Nil[49, 104106]
(8)Economic life in years3030303030[62]
(9)Total annual O&M costs1.0–1.5 US$/inhab. year4.0–8.0 US$/inhab. year4.0–6.0 US$/inhab. year1.5–2.5 US$/inhab. year10.98 Rupees Lacs/MLD [62, 92]
(10)Total construction costs12–20 US$/inhab.40–65 US$/inhab.50–60 US$/inhab.20–40 US$/inhab.42.04 Rupees Lacs/[62, 92]

and M costs are based on Indian Rupees in year 2008 and are calculated considering constant annual expenditure over the life of the plant.