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Comparison of Irrigation Qualities of Septic Tank Effluents
Reclaimed Using Aerobic- versus Anaerobic-Based
Treatment Systems

A. Abusam*, M.I. Ahmed, and A. Mydlarczyk
Wastewater Treatment and Reclamation Technologies (WTRT) Program, Water
Research Center Kuwait Institute for Scientific Research, P.O. Box 24885, Safat
13109, Kuwait.

International Journal of Abstract. Conventional septic tanks remove partially suspended solids and
Environment and organics from wastewater, but they do not remove nutrients and pathogens. The
Sustainability [IJES] Kuwait Institute for Scientific Research (KISR) studied a number of promising
ISSN 1927-9566 systems for the reclamation of effluents from conventional septic tanks. This
Vol. 5 No. 1, pp. 64-70 paper compares the irrigation qualities of the final products of aerobic- versus
(2016) anaerobic-based post-treatment systems. Reclamation of the effluents of a full-
scale conventional septic tank indicated that an anaerobic-based treatment
system resulted in lower salinity, fewer suspended solids, and smaller amounts
of organics than an aerobic-based treatment system. However, the aerobic-
based treatment system was found to be more efficient in the removal of total
nitrogen. Obtained results have also indicated that both treatment systems give
almost the same concentrations of boron and heavy metals. Therefore, it has
been concluded that reclamation of effluents of conventional septic tanks
requires both aerobic and anaerobic biological treatments

Keywords. wastewater, post-treatment, septic tank effluents, irrigation qualities,
aerobic treatment, anaerobic treatment

*Correspondence:

aabusam @kisr.edu.kw

1. Introduction A conventional septic tank system usually
consists of an underground watertight tank and
Wastewater of individual households or a drain field, which usually consists of trenches
collection of households is often treated in a filled with gravel and sand. The septic tank
septic tank system, which is the oldest waste- keeps the wastewater for some period of time
water treatment system (Okereke, 1997). In (preferably greater than 24 h) in order to be
many on-site wastewater treatment situations, treated anaerobically. The main functions of the
the septic tank system is considered to be the septic tank are: (i) to partially digest the organic
best option and disposal, as it is relatively matter, (ii) to remove settleable and floatable
inexpensive and almost a maintenance-free materials and accumulate them as sludge and
system. It has no moving parts and it does not scum, and (iii) to store the sludge until tank
require chemical addition (Fox, 1984). For these cleaning (Viraragahavan, 1976). On the other
reasons, septic tank systems are the most hand, the main function of the drain field is to
commonly used on-site treatment and disposal allow further treatment of the septic tank
systems all over the world. About 25% of the effluents before percolation into the surround-
homes in the United States of America (USA) ing soil.
use septic tanks. Also, about 22 million people
in Europe and about 60% of the Chinese Thus, conventional septic tanks remove only
population depend on the septic tank system parts of the suspended solids and organics
(US Census Bureau, 1999). The septic tank through sedimentation and anaerobic digestion,
system is also the common onsite wastewater before discharge into the soil. Thus, they
treatment system in remote, non-sewer areas of
Kuwait.