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International Journal of Environment and Sustainability, 2016, 5(1): 64-70 69
product waters clearly meet WHO guidelines for batch reactor (SBR) is another example of the
non-restricted irrigation (Table 3). systems that separate the aerobic and anaerobic
treatment conditions over time. Each of these
3.8 Heavy metals technological options has it merits and demerits
that should be taken into consideration. A
There are always health risks to crop con- hybrid aerobic-anaerobic system generally
sumers from irrigating using waters that are requires larger space. For SBR, however, avail-
highly concentrated with heavy metals (WHO, ability of power (electricity) and maintenance
2006). As Table 4 shows, both of the add-on skills are pre-requisites. Thus, the selection of
treatment systems had efficiently removed Al, post-treatment technology depends on the
B, Cu, and Zn. However, they were very poor in particular situation.
the removal of some heavy metals such as Fe,
Pb, Mn, and Ni. In fact, concentrations of heavy 4. Conclusions
metals slightly increased after post-treatment
due to leaching from grass filters. Except these Performance of an aerobic-based system as a
elements, two post-treatment systems resulted post-treatment system for conventional septic
in more or less the same heavy metal concen- tank effluents was compared to that of an
trations that satisfy the WHO standards. anaerobic-based post-treatment system.
3.9 Microbiological Quality Obtained results indicated that reclamation of
conventional septic tank effluents requires both
Break-point chlorination was used to disinfect aerobic-anaerobic treatments since none of
the final product waters. Chlorination often them can efficiently remove all pollutants of
results in up to six or more reduction units concern. Depending on the particular situation,
(99.9999%) of pathogen concentration (WHO, a hybrid aerobic-anaerobic biological treatment
2006). As expected, it resulted in the killing of system or a sequential batch reactor (SBR) can
almost all the pathogenic microorganisms be the best option for the reclamation of
(results are not shown here). Therefore, with effluents of conventional septic tanks for reuse
respect to microbiological quality, the two in irrigation purposes.
product waters satisfied the WHO standards.
Acknowledgments
3.10 Reclamation Technology
Data used in this study were collected during
The above-mentioned results clearly indicate the execution of a project entitled “Treatment,
that post-treatment of conventional septic tank Reclamation and Reuse of Effluent of Septic
effluents to a degree that satisfies irrigation Tank Treating Small Flow of Domestic Waste-
water quality, as specified by the WHO, requires water at Site (WT027C)” at KISR. This project
the use of both aerobic and anaerobic biological was partially financed by the Kuwait Founda-
treatments. This can be achieved through using tion for the Advancement of Sciences (KFAS)
a hybrid system in which aerobic and anaerobic under the code 2012-1505-02.
are separated in space or time. The add-on
system 2 used in this study is a good example of
the systems that separate the aerobic-anaerobic
treatment conditions in space. The sequencing
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USA Water in Un-Sewer Areas, Queensland Gov-
Ayers, R.S. and Westcot, D.W. (1985), Water
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