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66 © Abusam, Ahmed, and Mydlarczyk 2016 | Comparison of Irrigation Qualities
Sedimentation tank Effluent recycle to Chlorination
septic tank
Saturated Grass
Filter
Sand-gravel partially anaerobic bioreactor To storage tank
Pumping inflow from septic tank outlet
Figure 2: The anaerobic-based post treatment system (Abusam et al., 2014)
2. Material and Methods 3. Results and Discussion
The two add-on reclamation systems were The quality of the final product waters of
operated using the effluent of a full-scale systems 1 and 2 are shown in Table 4. The
conventional septic tank as an inflow. They following sections compare and discuss the
were operated at inflows of 0.5, 0.8, 1.1, 1.4, and quality parameters of the two final product
1.6 l/min. and flow recycling rates of 25%, 50%, waters. It also briefly discusses the techno-
75%, and 100%. Quality of the septic tank logical options for the reclamation of effluents
effluents used in the tests is presented in Table of conventional septic tank systems.
1. At steady state conditions, weekly samples of
the system’s final product water were collected 3.1 pH
and analyzed according to APHA (2012). The
temperature (Temp.), hydrogen concentration Table 4 shows that the mean pH values of the
(pH), dissolved oxygen (DO), and electrical final product water of the two add-on treatment
conductivity (EC) were measured in situ, while systems were exactly the same (7.2 +/- 0.2) and
the following parameters were determined in that they were within the range (6.5 to 8.0)
the laboratory: five-days biological oxygen recommended by WHO. Notice that pH outside
demand (BOD5), chemical oxygen demand this range may adversely affect the plants
(COD), total suspended solids (TSS), total through nutritional imbalance or toxicity. Irri-
dissolved solids (TDS), oil and grease (O&G), gation water with a pH value that is lower than
ammonia nitrogen (NH4-N), nitrate nitrogen 6.5 usually promotes leaching of heavy metals,
(NO3-N), total Kajeldahl nitrogen (TKN), total whereas that with pH value higher than 11
nitrogen (TN), phosphate (PO4), hydrogen destroys bacteria and can also temporarily
sulfide (H2S), phenol (C6H5OH), total coliform inhibit movement of heavy metals (WHO, 2006).
(TC), fecal coliform (FC), fluoride (F), boron (B),
cadmium (Cd), lead (Pb), mercury (Hg), zinc 3.2 Salinity Hazards
(Zn), arsenic (As), aluminum (Al), copper (Cu),
iron (Fe), manganese (Mn), nickel (Ni), and Highly saline water generally damages soil,
magnesium (Mg). Notice that break-point plants, groundwater, and/or crops. Accordingly,
chlorination was used to disinfect the final it is generally recommended that salinity of the
effluents. Tables 2 and 3 present the WHO irrigation water should not be very high. Table
guidelines, which was used as a criteria for the 4 shows that salinity measured as EC and TDS of
comparison. the final product waters of system 2 were
slightly lower than that of system 1. However,
according to WHO standards (Table 3), both
effluents require a high degree of restriction
with respect to EC. They also both require a
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