الفهرس 
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Abstract
Wastewater treatment is one of the important subjects taken into
consideration in developing countries. In such countries, the main source
of pollution is due to discharging wastewater without adequate treatment
into watercourses.
The use of conventional types of wastewater treatment in these
countries in the rural areas is hindered by the huge investments and large
area requirements of agricultural land. These reasons led the scientific
community to seek solutions relying on the use of local products or byproducts
to establish low cost wastewater treatment systems employing
new modified techniques suitable for serving different specific conditions.
Also, the concentration on minimizing of power consumption,
maintenance requirements, complicated techniques and imported
equipment became one of the main targets for the ongoing studies. This
leads to choose the attached growth system after the anaerobic treatment
unit to decrease the required land, minimize the construction and
operation cost as possible and reach the requirements of law 48.
This study was carried out to check the possibility of applying
biological filters following the USBR system. The biological filter
receives the Down-flow effluent from the USBR system, which drops
through perforated trays to increase the DO in level, before being
introduced to the biological filter.
Four selected different filtration packed media were used as
aerobic biological filter units. All the media are available in the local
market, the tested media (sponge, plastic, Electrical flexible corrugated
hoses, and gravel) were used in parallel modules to evaluate the
performance of each separately and determine its removal efficiency for
the different pollutants represented by the parameters COD, CODs, TSS,
and VSS. To achieve the study objectives the tested media were exposed
to several hydraulic loading rates and shock load during the experimental
program using continuous flow pilot plant running for seven months
period.
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The use of passive aeration after the anaerobic phases of the treatment increases the dissolved oxygen contents of the anaerobic effluent to reach an average concentration of 5.22 mg/L.
All tested media achieved good removal efficiency of the
monitored pollutants under hydraulic loading rate of 2.5m3/m2/day to
12m3/m2/day and produced effluent quality that meets Law 48
requirements most of the time.
The best removal efficiency occurred at hydraulic loading rate
range of 2.5-3.75m3/m2/day for all tested media. The best two media,
however, were sponge and plastic.
All the tested media were affected during the shock load and
impaired the effluent quality, but after 48 hours effluent quality returned
back to the regular background range except gravel.
The sponge media was the best media for all hydraulic loading
rates due to the big surface area and the high catchment of water that keep
the biofilm wet at low hydraulic loading rate.
KEY WORDS :
Wastewater, Wastewater Treatment, Attached growth
system, Biological filter media, low cost treatment system.