الفهرس 
Municipal solid wasteOnly 14 pages are availabe for public view
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Abstract
Because of rapid population growth during the recent decades, and the
explicit lifestyle development in many countries around the world, a huge amount of
municipal waste is generated daily. Solid waste is considered as one of the most
complicated environmental problem in many countries, particularly in the
developing countries. Disposal of solid waste using sanitary or random landfilling
technologies is the most popular applied method in many areas, and usually, it’s
considered as the lonely way to dispose the waste of many countries.
Solid waste landfill produces a very toxic and highly contaminated solution
called “leachate”, according to the composition of the leachate, it is a real threaten to
the environment around the landfill, specially ground water aquifer, surface water,
agricultural soil and others natural ecosystems, and it needs to serious and scientific
attention and treatment before discharge to the environment.
The leachate consist of many toxic and hazardous contaminants which
produced by the decay of several dumped waste throughout the various periods of
time landfill age. Organic material (COD) and ammonia are some of this important
toxic material. The deep thinking in developing of how to treat this leachate and
remove this toxic material is considered as one of the modern concerns and threats
facing the scientists and related organization around the world in order to protect the
environment and its various components from the pollution.
7.1 Aim of the study:
To assess the treatment of municipal solid waste stabilized leachate using
persulfate-based advanced oxidation processes in Gaza Strip, Palestine.
7.2 Plan of study implementation:
7.2.1 Literature review:
Researcher has implemented a wide range and comprehensive reviewing of
most related studies and projects before starting the current study in order to
determine the real gaps and needs in the topics related the study subject, to enhance
the knowledge of the researcher in the field of the study and to enrich the
dissertation.
7.2.2 Study location:
• Leachate samples were collected from a leachate collection ponds of the
landfill at the DBLS (Deir El-balah Landfill Site), it is located at Deir ElBalah
city, Middle Governorate in Gaza Strip, Palestine, at a coordinate of
31° 23.50’ N & 34° 22.77’ E).
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• The laboratory part of the study has been implemented at the Public Health
Laboratory/ Palestinian Ministry of Health (MoH).
7.2.3 Samples and Sampling processes:
In this study, the leachate samples were collected manually once every week
for 4 months between February 2014 and June 2014 and placed in 2 L plastic
containers. The samples were immediately transported to the laboratory,
characterized, and cooled to 4 °C to minimize the biological and chemical reactions.
Sampling processes and storage techniques were implemented according to the
international standard methods.
7.2.4 Study design
An experimental study
7.3 Study results:
The current study was implemented in order to evaluate the effectiveness of
persulfate and persulfate/hydrogen peroxide oxidation processes separately in
removing COD and ammonia from stabilized leachate of MSW under different
experimental conditions using techniques of AOP. The performance of these two
treatments in removing COD and ammonia was investigated. Moreover, the effects
of these techniques on biodegradability and organic behavior in stabilized leachate
were documented. According to the obtained results, a treatment unit was suggested
with all needed parameters to achieve the best removal efficiency of the organic
pollutant and ammonia contaminant in the effluent.
The equations for COD and ammonia removal using RSM were established,
and the optimum operational conditions for the two oxidation processes were
investigated as follows:
7.3.1 Classical oxidation process using persulfate alone:
The current study determined the optimum conditions for anaerobic
stabilized landfill leachate treatment using persulfate oxidation. In order to obtain an
optimal S2O8
2− dosage; and by applying classical oxidation processes, different
dosage of persulfate was determined as the COD/S2O8
2− (g/g) ratio, ranged from 1/1,
1/1.2, 1/1.4, 1/1.6, …… to 1/5 (g/g) during 60 min of oxidation and pH 7 at room
temperature (28 0C). The results show increasing of removal efficiency of COD and
ammonia as the dosage of S2O8
2− is increase. The maximum removal of COD and
ammonia were 45% and 47%, respectively at 1/4.2 (COD/S2O8
2−g/g).
7.3.2 Optimization of leachate treatment process using persulfate alone:
By using RSM, an optimization processes was conducted, the optimum
conditions for the treatment were conducted with respect to operational conditions,
namely,S2O8
2− concentration (4.20g S2O8
2−/1g COD), pH (7) variation, and reaction
time (60 min).The maximum removal efficiency for COD and NH3-N was 46% and
48%, respectively. According to the results, the performance of persulfate alone was
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poor, and utilizing new advanced oxidation material during oxidation of such
leachate was required to improve leachate treatability.
7.3.3 Classical oxidation process using persulfate/H2O2:
Hydrogen Peroxide was added in order to enhance oxidation processes by
increasing sulfate radicals (SO4
-•) generation. The performance of an advanced
oxidation process, consisting of the combined use of persulfate and hydrogen
peroxide for the treatment of stabilized landfill leachate was investigated. According
to the classical oxidation processes, the maximum removal efficiency for COD and
NH3-N was 81% and 83%, respectively, at optimal operational conditions of
5.88g/8.63g persulfate/ hydrogen peroxide dosage, pH 11, and a reaction time of 120
min.
7.3.4 Optimization of leachate treatment process using persulfate/H2O2:
Using of RSM software, the optimum working conditions and respective
removal efficiencies were established: About 82.1% and 85.4% removal of COD
and NH3–N are predicted, respectively based on the model and under optimized
operational conditions (4.96g/7.29g S2O8
2−/H2O2, pH 11 and reaction time 116 min).
7.3.5 Effect of persulfate and persulfate/H2O2 on biodegradability of landfill
leachate:
In the present study, the effects of S2O8
2− and S2O8
2−/H2O2 on
biodegradability and solubility of the solid waste leachate were investigated.
Biodegradability, defined as BOD5/COD, improved from 0.089 to 0.1 and 0.17
using S2O8
2− and S2O8
2−/H2O2, respectively. Biodegradable fraction of COD
improved from 36% to 57% and 64% after S2O8
2− and S2O8
2−/H2O2 oxidation,
respectively. Soluble COD(S) fraction increased from 70% to 78% after S2O8
2−, and
increasing in COD(S) to 90% was obtained using S2O8
2−/H2O2.
Biodegradable soluble COD(Sbi) fraction increased from 52% to 72% after 60
min of persulfate alone and to 75% using persulfate/H2O2 oxidation process with
120 min, whereas COD(Subi) fraction was reduced from 49%to 28% and 25% as
effects of persulfate and persulfate/H2O2, respectively. The study suggests that
biological treatment steps could be applied as a post-treatment process after using
the combined S2O8
2−/H2O2 oxidation system in the AOP for further biodegradation
of organic in leachate.
7.3.6 Proposed data for stabilized leachate treatment plant using
persulfate/hydrogen peroxide in AOPs:
Suitable data were presented to establish fully stabilized leachate treatment
plants using S2O8
2−/H2O2. The proposed volume for treating stabilized leachate is
1m3
. The effluent characteristics of S2O8
2−/H2O2 for COD (1171 mg/L) after 14 days
by final removal efficiency of about 94.3% of COD, but ammonia was significantly
removed during the first day of aeration (85.4%). The effluent was able to be treated
by other additional treatment steps such as biological treatment to produce a suitable
treated leachate for discharge to the environment safely.
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110
7.4 Recommendations:
According the findings of the current study, several recommendations were
addressed for other researchers as follow:
1) Biological treatment after S2O8
2−/H2O2 process is recommended to enhance the produced
effluent leachate quality by further ammonia and organic material removal.
2) The utilization of S2O8
2−/H2O2 processes on different leachate types and a different initial
concentration are recommended to reach higher removal efficiency and a better
understand of the degradation mechanism.
3) Investigation of the effectiveness of full scale stabilized leachate treatment plant using
S2O8
2−/H2O2 processes is recommended.
4) More studies related to the efficiency of S2O8
2−/H2O2 using as treatment technology in
combination with other treatment techniques such as physical, biological or chemical,
are needed to enhance the treatment processes.