الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 321 |  |  |
| | | from | 321 | | |
Abstract
Wastewater treatment has always been a major concern
in the developed countries. Granular activated carbon (GAC)
is a promising technique for removal of organics from water
and wastewater. Although the use of GAC can be a rather
expensive process, the cost can be greatly reduced by proper
design of the treatment units.
Over the last decades, activated carbon adsorption has
gained importance as an alternative tertiary wastewater
treatment. GAC as tertiary treatment to biological effluent was
studied at Zenein Wastewater Treatment Plant, Giza.
The aim of present study is determine the optimum GAC
columns fixed and fluidized flow pattern (down flow & upflow
modes), which could be applied for tertiary treatment of
biologically treated wastewater.
A pilot plant was designed and constructed at Zenien
WWTP which consists of three plexiglas columns filled with
GAC. The pilot plant was fed from the effluent of the
secondary clarifier of Zenien plant, and operated for a period of
about fourteen months.
The’ experimental work was divided into four main parts
namely; fixed carbon column, fluidized carbon column,
comparison between fixed and fluidized carbon column and
fmally dual sand / carbon columns.Results of experiments showed that triple fixed carbon
column can produce a removal ratio of BODs and COD equal
to 82 % and 59 %, while fluidized column 78 % and 58 %.
BODs, COD, and TSS in the tertiary effluent using fixed
GAC columns were 2.7 mg/L, 20.1 mg/L and 3.3 mg/L, which
comply with the Egyptian Law No 48 for year 1982.
Removal of BODs ill sand and carbon columns was
equal to 40 % and 80 %, while COD equals to 45 % and 65 %.
Removal of of BODs, COD, and TSS was improved by
increasing the empt bed contact time (EBCT). A rate of
filtration through GAC columns of 100 m3/m2/day, which is
corresponding to an EBCT of 8 minutes was proved to be
suitable and economical using GAC columns.
Using sand column prior to GAC column tends to
increase the life’ of carbon column and also improves the
quality of treated wastewater. Sand column also tends to
increase the removal of BODs and COD by 14 % and 30 %
respectively, compared with single fixed carbon column alone.
A mathematical model has been established to predict
the values of removal of BODs or COD for single fixed
column, knowing the initial concentration of BODs or COD,
empty bed contact time (EBCT) and surface area of carbon
grams.
Economic analysis indicated that GAC columns could be
economically competitive with the other alternatives of
conventional physiochemical treatment processes. The cost
estimates of tertiary treatment of Zenein WWTP effluent using GAC filters including capital and 0 & M costs, amounts to
0.50 LE/m3 of treated effluent based on regeneration interval of
two months. This cost estimates could be reduced to 0.37 and
0.34 LE/m3 if the regeneration interval increased to 6 and 12
months respectively