Volume 14 [2012]

Improving the treatment efficiency of a primary wastewater treatment plant(WWTP),in Alexandria,
Egypt,was studied.In order to improve the treatment efficiency of the plant, different improving
scenarios were proposed and evaluated. The improvement scenarios are: scenario 1,use of
engineered wetland instead of the current treatment system, scenario 2, use of the engineered
wetland as a secondary treatment after the existing treatment system and scenario 3,replace the
existing treatment system with a secondary WWTP. The scope of this study is to environmentally
assess the existing primary WWTP, in addition to assess the possibility of using the engineered
wetland for improving the primary WWTP. To evaluate the performance of each treatment system,
Life Cycle Assessment (LCA) approach was applied.

Based on the results, the main improvement achieved in all the scenarios is in the category of
eutrophication and acidification, as the three scenarios have higher removal efficiency for the
nutrients than the current system. Unlike the total reduction in the environmental impact, scenario 3
gave the highest reduction in the category of eutrophication and acidification (25%) followed by
scenario 2 (24%) and the lowest reduction achieved by scenario 1 (13%). The analysis revealed that
the use of combined system from natural and traditional systems (scenario 2) is the best scenario.
However, scenario3 achieved a very close result.

Electrically and ionically conducting graphite powder beds interposed between the anode and
cathode inside an electrolytic setup are used as intermediate bipolar electrodes. The beds cause
electric field discontinuity by eliminating the applied electric field locally within their mass and act as
electrostatically shielded zones – ion and ionic current sinks and thus ion concentrating
compartments, whereas the adjacent compartments become ion depleting compartments. The ion
sinks were implemented in a coupled electrostatic shielding electrodialysis/electrodeionization
process to remove ammonium nitrate from fertilizer plant wastewaters. The batch wise operated
electrostatic shielding electrodialysis of a solution containing 1310 mg L-1 ammonium nitrate
produced in 28 min at a current density of 15-30 A m-2 a concentrate ammonium nitrate solution
which could be recycled to the fertilizer plant unit and a diluate containing 50 mg L-1 ammonium
nitrate. The diluate was subsequently used as feed in the electrostatic shielding electrodeionization
process to produce pure water of a NH4
+ and NO3- ion concentration of less than 1 mg L-1
respectively with a flow rate of 5.51x10-4 dm3 s-1 and a current density of 50 A m-2.

Treatment of young landfill leachate, collected from municipal solid waste site of city of Konya, was
investigated by using the Fenton process. The leachate itself showed the characteristics of pH 7.25,
COD 38.2 g L-1 and BOD5 22 g L-1. Ratio of BOD5 to COD with 0.58 indicates that leachate can be
defined young. Fenton oxidation of landfill leachate was expressed in two-stage process, where a
fast initial reaction (H2O2/Fe2+) was followed by a much slower one (H2O2/Fe3+). Overall kinetics can
be described by a second-order rate equation followed by zero-order one. The kinetic studies were
undertaken at the different temperatures and reaction rates increcesed by increasing temperature.
The apparent kinetic constants at 303 K are k = 3.16 x10-3 L g-1 min-1 and k0 = 0,171 g L-1 min-1,
respectively. Fenton reagents effectively degraded the leachate organics and most of the
degradation was completed within 30 minutes for all temperatures. The performance of Fenton
process was not only presented as a COD removal but also expressed as the amount of generated
sludge and its properties. Sludge properties were revealed with Capillary Suction Time (CST) and
Sludge Volume Index (SVI). The minimum CST value was obtained at the optimum molar ratio of
4.12 mol/mol and increasing temperature resulted in a positive effect on CST values. All SVI values
were significantly low which indicates that sludge itself had good settling properties.

A considerable number of diseases are directly related to environmental impact. Toxic metals such
as Hg, Pb, Cd, and As may damage significantly the human health when they exceed certain levels
in the body. For example specific precautions should be taken for the diet of pregnant women and
the children. Lead concentrations exceeding the safe values can cause severe damage to the
development of central nervous system, as well as a general developmental delay of fetuses and
young children, interfering with the functioning of almost every brain neurotransmitter. In particular
for the pregnant women, it has been found that the exposure of the fetus on high lead values may
cause, apart from neurological and behavioral problems, low birth weight, pre-term delivery,
spontaneous abortion and stillbirth. Organic mercury (methyl mercury) is the most dangerous form of
mercury, because it is the most easily absorbed orally and crosses into the brain and fetus so
readily. Populations exposed to chemical compounds containing As, Ni, Cr, Cd, etc. are considered
of high-risk in developing cancer.
Environmental geochemical studies can help in assessing the quality of the environment as well as
the determination of the sources of pollutants, their behaviour and other characteristics. This
knowledge is necessary in any application of remediation methodologies and waste management for
the prevention of pollutants in getting into the food chain. It is also used in determining safe criteria
regarding the quality of soils, drinking water, construction of schools, playgrounds etc. In this work
the importance of environmental geochemical research and its applications towards the protection of
human health is demonstrated.