Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Activated Sludge

Effect of Continuous and Intermittent Aeration Modes on the Efficiency of the Continuous Flow Extended Aeration Activated Sludge Systems

Kossay K. Al-Ahmady; Ammar A. Al-Sultan

Engineering and Technology Journal, 2014, Volume 32, Issue 13, Pages 498-512

In this research an experimental plant was constructed and operated in order to study the efficiency of the intermittent aeration activated sludge system that operated at the ratio of (On/Off aeration times) (15min/15min), (30min/30min), (60min/60min), (90min/90min) and (120min/120min) and compare their performance with the continuous flow extended aeration activated sludge. The results of the study revealed that; extended aeration reactor is more efficient in removing organic matter than the intermittent aeration reactors. At the hydraulic detention times of (24, 18 and 32), 100%, 65% and 100% of effluent readings had organic concentration less than the acceptable effluent level in compare to 75%, 60% and 80% at the (90min/90min) reactor. In comparison of On/Off aeration times, (90min/90min) reactors provide the best organic removal. All readings from the extended aeration and (15min/15min), (60min/60min), and (90min/90min) reactors were within the acceptable level for effluent suspended solids while the effluent concentrations from the (120min/120min) reactors were higher. The results also indicated that, intermittent aeration reactors are better in removing phosphorous than the extended aeration. At the detention times of 24 and 18 hours, 8% and 6% of readings from the extended aeration reactors had (PO4 ≤ 5 mg/l) in compare to 90% and 52% of readings from the (60min/60min) reactor. At detention time of 32 hours, 32% of readings from the extended aeration reactor had (PO4 ≤ 2 mg/l) in compare to 72% for the (60min/60min) reactor. Higher phosphorus removals were recorded at (60min/60min) reactors.

Performance Comparison of Activated Sludge Systems at Mesophilic and Thermophilic Modes in Treating Dairy Wastewater

Kossay K. Al-Ahmady; Mohamed Sameer Ghanim

Engineering and Technology Journal, 2013, Volume 31, Issue 2, Pages 32-45

In this research, two activated sludgeexperimental laboratoryplants were
constructed and operated using dairy wastewater. One of these plants were operated
at high temperatures of (40 – 60 oC) “Thermophilic microorganisms reactors",
whereas the other one were operated at constant temperature of (25 oC)“Mesophilic
reactor”. The resultsshowed that the organic removal efficiency of "Mesophilic
reactor" was more than the "Thermophilic reactors" and it decreasedwith increasing
the temperature.The kinetic parameters for the both mode of operations were also
calculated. The value of the substrate removal rate constant (k) for the "Mesophilic,
25ºC" reactor was (0.017 day-1) and it was greater than others for the thermophilic
reactors.(k) and (Y) decreased with increasing the temperature. The values of (Ks),
(Umax), and (Kd) in the thermophilic reactors were more than the corresponding values
in the mesophilic reactor and increased with increasing the temperature.

Testing the Applicability of Submerged Hollow Fiber Membrane Bioreactor (MBR) Technology for Municipal Wastewater Treatment in Iraq

Talib R. Abbas; Mohammed A. Abdul-Majeed; Inmar N.Ghazi

Engineering and Technology Journal, 2012, Volume 30, Issue 19, Pages 3467-3473

Operation of a one module hollow fiber submerged type MBR system was
tested in this work. The system was operated at fixed permeate flowrate of 12 l/hr.
The hydraulic retention time of the aeration tank was about 8.3 hr. The mixed
liquor suspended solid (MLSS) concentration was maintained in the range 5000-
5500 mg/l. The results show the workability of this system under Iraqi conditions
without any difficulties. About 85% chemical oxygen demand (COD) removal
was achieved. The value of turbidity is well below 0.61 NTU throughout the
operation time.