الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The increasing environmental awareness of the world community to provide
proper and efficient engineering solutions to wastewater treatment as part of a
global strategy to control the pollution is the motive to carry out researches on
enhancement of treatment technologies and improving their performance.
The membrane bioreactors (MBR) technology is among the most recent
promising innovations for wastewater treatment which give very high treatment
efficiency.
This study was carried out to assess the feasibility of combination between
intermittent UASB with submerged membrane bioreactors to develop two stages
(UASBIMBRl) for the treatment of domestic wastewater (sewage). Two
treatment systems were operated in parallel, two stages (UASBIMBRl) system
and single stage (MBR2) system.
The field experimental work was divided into different phases:
First phase: investigation and assessment of the combination between the
intermitted UASB under mesophilic (25°C) conditions and the MBR
system in a two stage UASBIMBRI compared with the single stage
MBR2 system.
Second phase: to study the performance of the two stage UASBIMBRI
system with comparison with single stage MBR2 system under high flux
rates (40-50 Vm2/hr).
Third phase: to study the performance of the MBRs under moderate flux
rates (20-25 Vm2/hr).
Fourth Phase: to study the effect of the shock organic load on the
performance of the two stage UASBIMBR system.The performance of both MBRs systems were evaluated regarding the prolonged
steady operation period, the steady operational flux rate the trend for TMP increase, the chemical cleaning frequency and clean flux recovery after cleaning
steps, and also, the treatment efficiency.
The proposed combined UASBIMBRI system improved the operation
performance ofMBRI to achieve maximum water recovery, higher permeate flux
accompanied by less biofouling and less need. for chemical cleaning of the
membranes.
According to the obtained results, the present study resulted in the following
conclusions:
• the two stage UASBIMBRI systems shows a very high removal efficiencies
with respect to the biological oxygen demand (BODS), the total suspended
solids (SS), and chemical oxygen demand (COD) rather than single stage
. MBR2 system, i.e., the average effluent concentration of BODS was 4 mg/l
with a removal ratio of 98.6 % and the effluent concentration of COD was 46
mgll with average removal ratio of 90 % and the suspended solids on the
effluent were not detective «2 mg/l), under normal operation conditions.
• The efficiencies achieved by the intermittent UASB during the whole study for
CODcsF, CODcF, CODDF, and SS were 61%, 37%, 26%, and 51%,
respectively.
• Making use of the produced biogas according to the anaerobic degradation of
the wastewater can overcome a high percent of the energy cost required by the
MBRsystem.
• The most appropriate concentration of the mixed liquor suspended solids for
the MBR is range from 8 to 12 gil for good aerobic biodegradability and proper
steady operation of the MBR system.
• The steady operation period was in range from 2.75 to 3 times higher with
MBRl(two stage UASBIMBR1) rather than single stage MBR2, and hence the
cleaning frequency was less leading to increasing the life time for the
membranes unit and decreasing the cost for the membranes.
• The cleaning rate is reduced for the two stage UASBIMBRI system with 65%
saving the chemical required and avoiding the bad effect of the used chemicals
on the life time of the membrane units. The combined UASBIMBR.l system was capable to handle the high organic
shock load achieving removal ratio for COD total equal to 92.3% compared
with 62.3