Page 78 - IJES Special Issues for AIEC2016

68 © Abusam, Ahmed, and Mydlarczyk 2016 | Comparison of Irrigation Qualities

Table 3 3.5 Total Nitrogen

Recommended Maximum Concentrations of Nitrogen is an essential macronutrient for plant
Trace Elements (Ayers and Westcot, 1985) growth. Nitrogen is usually found in wastewater
as ammonia, nitrite, nitrate and/or organic
Trace Element Maximum Concentration (mg/l) nitrogen compounds. Total nitrogen (TN) is the
Al 5.0 sum of all these different forms of nitrogen.
Cd 0.01 According to the WHO guidelines (Table 3), no
Cr 0.10 degree of restriction is required when TN is less
Co 0.05 than 5 mg/l while a slight to moderate degree of
Cu 0.20 restriction is required for irrigation when TN
Fe 1.0 between is between 5 to 30 mg/l. Generally, TN
Pb 5.0 less than 30 mg/l does not harm plants, except
Mn 0.20 sensitive crops such as sugar beets (Ayers and
Ni 0.20 Westcot, 1985). As given in Table 4, the aerobic-
Zn 2.0 based post treatment system had reduced
significantly TN concentrations (4.8 ± 3.5 mg/l),
Table 4 while that of the anaerobic post treatment
system remained high (41.3 ± 15.3 mg/l). The
Quality of the Final Product Waters of Systems 1 high removal of TN of the aerobic-based system
and 2 can be attributed to high nitrification (oxidation
of ammonia) in the aerobic bioreactor and sub-
Parameter Process 1 Process 2 sequent denitrification in the grass soil filter. It
Mean Standard Mean Standard should be noticed that such high removal of
pH nitrogen is usually not required when the
EC (µS/m) Deviation Deviation reclaimed water will be used as irrigation
TSS water.
TDS 7.6 0.2 7.6 0.2
NO3-N 9.42 3.4 8.24 0.32 3.6 Phosphorus
NH4-N 16.4 1.8 7.4 2.1
TKN 648.9 853.4 316 29.1 Phosphorus is also an important macronutrient
TN 5.4 3.7 37.4 15.9 for plants. It is commonly present in significant
PO₄ 3.8 1.5 2.9 2 amounts in wastewater. Table 4 shows that the
COD 1.6 1.5 37.9 16.1 anaerobic-based system resulted in a higher
BOD5 4.8 3.5 41.3 15.3 removal of phosphorus than the aerobic system.
DO 8.8 4.1 4.7 0.9 Concentrations of phosphorus in the final
O&G 53.1 60.6 27.5 4.3 product waters were 4.7 ± 0.9 mg/l for the
C6H5OH 24 27 9.3 2 anaerobic-based system and 8.8 ± 4.1 mg/l for
F 2.2 0.6 1.1 0.3 the aerobic-based system. These results
H2S 0 0 00 indicate that huge amounts of phosphorus, that
Al 0.02 0.02 00 would have been beneficially recycled through
As 0.4 0.24 0.4 0.2 agricultural irrigation reuse, was removed by
B 0.01 0.012 00 the anaerobic-based system.
Cd 0.29 0.2 0.6 0.3
Cu 0 0 00 3.7 Boron
Fe 0.14 0.13 0.2 0.2
Pb 0 0 00 Boron is also an essential micronutrient needed
Mn 0.03 0.04 00 for plant growth. However, high concentrations
Hg 0.31 0.37 0.2 0 of boron can affect particularly ornamental
Ni 0.13 0.15 00 plants (WHO, 2006). As presented in Table 4,
Zn 0.1 0.1 0.4 0.4 there is no significant difference between boron
Mg 0 0 00 concentration of the final product water of the
0.24 0.52 1.1 0.9 two systems. Furthermore, the two final
0.08 0.07 0.6 0.4
16.38 8.1 19.4 3.7

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