The UASB reactor as an alternative for the septic tank for on-site sewage treatment

• Published in: Water Science & Technology Vol. 48; no. 11-12; pp. 221 - 226
• Main Authors: COELHO, A. L. S. S, DO NASCIMENTO, M. B. H, CAVALCANTI, P. F. F, VAN HAANDEL, A. C
• Format: Conference Proceeding Journal Article
• Language: English
• Published: London IWA 01-01-2003; IWA Publishing
• Subjects: Applied sciences; Biological and medical sciences; Biological treatment of waters; Bioreactors; Biotechnology; Colloids; Construction costs; Cost Control; Developing Countries; Effluents; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Infiltration; Other wastewaters; Pollution; Reactors; Septic tanks; Sewage; Sewage - chemistry; Sewage - microbiology; Sewage disposal; Sewage tanks; Sewage treatment; Sludge; Suspended solids; Waste Disposal, Fluid - economics; Waste Disposal, Fluid - methods; Wastewater treatment; Wastewaters; Water Purification - economics; Water Purification - methods; Water treatment and pollution
• DOI: 10.2166/wst.2004.0846
• EISSN: 1996-9732
• ISBN: 1843394561; 9781843394563
• ISSN: 0273-1223

Although septic tanks are amply used for on site sewage treatment, these units have serious drawbacks: the removal efficiency of organic material and suspended solids is low, the units are costly and occupy a large area and operational cost is high due to the need for periodic desludging. In this paper an innovative variant of the UASB reactor is proposed as an alternative for the septic tank. This alternative has several important advantages in comparison with the conventional septic tank: (1) Although the volume of the UASB reactor was about 4 times smaller than the septic tank, its effluent quality was superior, even though small sludge particles were present, (2) desludging of the UASB reactor is unnecessary and even counterproductive, as the sludge mass guarantees proper performance, (3) the UASB reactor is easily transportable (compact and light) and therefore can be produced in series, strongly reducing construction costs and (4) since the concentration of colloids in the UASB effluent is much smaller than in the ST effluent, it is expected that the infiltration of the effluent will be much less problematic.