Tikrit Journal of Engineering Sciences

The continuous sequential biological anaerobic/aerobic treatment of Samarra Drugs Factory wastewater (pharmaceutical wastewater) was evaluated under different operation conditions of hydraulic retention time (HRT). A pilot plant of upflow anaerobic filter (UAF) was used for anaerobic stage followed by air diffuser for aerobic stage. The UAF was fabricated from polyvinyl chloride (PVC) pipe with 14 cm diameter and 140 cm height. The UAF was packed with (2.54-3.82) cm inert gravel as a media .Three ports along the UAF were fixed at distance of (30cm) to evaluate the reactor efficiency with respect to the depth. The system was operated for (135days) continuously .Seeding and acclimation of anaerobic bacteria for start- up of UAF was achieved within (34days) by using glucose and trace nutrient with gradually replacing pharmaceutical wastewater, then the system was operated completely with pharmaceutical wastewater for three runs with three values of HRT, each run was 30 days. The values of HRT were (24 hrs, 18hrs, and 12hrs) for anaerobic stage and (20 hrs, 15hrs, and 10hrs) for aerobic stage respectively. The UAF was operated with mesophilic bacterial growth, in which the temperature maintained with the range of 35-37 oC. The removal efficiency for chemical oxygen demand (COD), biochemical oxygen demand (BOD) Nitrate (NO3), Phosphate (PO4), Sulphate (SO4), Total suspended solids (TSS) by anaerobic filter were evaluated, while only the removal efficiency for COD and BOD were evaluated with the sequential anaerobic/aerobic treatment. The system was subjected to pharmaceutical wastewater with COD concentration ranged (740-1100 mg/L) and BOD concentration ranged (298- 400 mg/L). The removal efficiency of COD and BOD were 87%, 90% for anaerobic stage and 92%, 93% for anaerobic/aerobic stage respectively. The biogas production was (0.55 m3/Kg COD removed). The efficiency of anaerobic filter with respect to the depth showed that the first third was the more effective in COD removal.

The finite element method is used to investigate the behavior of a strip footing constructed near the edge of a sloping cohesive ground. The effects of variation in footing closeness, loading eccentricity and slope angle are studied also. It is proved that Bowles method overestimates the load carrying capacity of the concentrically loaded strip footings on cohesive soils. Decreasing the distance between the footing and the slope edge, increasing the eccentricity and slope angle reduce the ultimate bearing capacity. Slope effect diminishes as the footing distance from the edge approaches (1.5) times its width.

A theoretical and experimental investigation of the normal impact of a flat-ended liquid slug onto ductile cylindrical solid targets is presented. The liquid slug is simulated by wax which is known to behave as a liquid in high speed impact situations. Both concave and convex types of the cylindrical target were used. The pattern of damage of the impacted Aluminum targets reveals compressed and ripple-damaged surfaces. While the convex target can be treated well by the modified model put by Kiter & Salem[5], the same cannot be said to the concave target.

In this research ,the effect of cohesive soils ( clay ) and non –cohesive soils sand on equilibrium scour depth was studied .Experiments were carried out on two types of clay and two types of sand as a bed material using an obstruction ( pier ) to create a local scour. The effect of flow velocity and Froude number on scour depth and the occurrence time of equilibrium scour depth were studied . The results show that for the same conditions, the rate of scour in the clayey soils is less than in sandy soils. Also the time required for occurrence of the maximum scour depth ( equilibrium depth ) in clayey soils is more than in sandy soils. Two formulas were found to predict the equilibrium scour depth in terms of Froude number ,the first is for clayey soils and the second for sandy soils .

A study has been done on experimental investigation of the flow characteristic of water falling film in spiral tubes. The ratio of the surface film velocity to average film velocity (us/uF) is less than 1 for low angle of inclination (4-8 o) where as it increases as the angle of inclination increases reaching a value of about us/uF = 1.2 . This small value of the velocity ratio is due to the liquid film rotation in coil which causes some deletion. The film thickness (δ) experimental data correlated well bythe following equation: δ = 0.0048 ReF0.7064 sin-1/3θ ( with R2 = 0.959 )

An experimental study on forced convection heat transfer from an embedded horizontal cylinders array in a porous medium in cross flow was carried out under constant heated cylinder surface temperature condition. The study included the effect of Peclet number, heated cylinder location in array, and the spaces between cylinders on the heat loss ability from this cylinder, as well as the enhancement in heat transfer rate due to embedding the cylinders array in a porous medium. An experimental set-up was used for this purpose which consists of a blower, air duct, test section, and heating element which is represented by a copper cylinder with a diameter of (12.7 mm) heated internally by an electrical source, which represents transfer and heat loss element through this set-up. The experiments were done at the range of spacing ratios between (1.2 ≤ S / D ≤ 2 ) for the cylinders array consisting of five embedded horizontal cylinders in a porous medium consisted of Alumina granules with a particle diameter rate of (3.938 mm) in a turbulent flow at Peclet numbers between (15 < Pe < 56 ). The study showed that the ability of heated cylinder to heat loss is a function of Peclet number, its location in array, and the spaces between cylinders. This ability is increased by increasing Peclet number, and it was shown that this ability reaches maximum value at the third cylinder in array at a spacing ratio of (S/D=1.6) and also at the fourth cylinder in array at a spacing ratio of (S/D=1.4). Also, it was shown that the heated cylinder at any location in array for almost spacing ratios, there was an increase in the heat transfer as maximum (21%) in comparison with a single embedded cylinder in a porous medium. It was noticed that the maximum enhancement value of heat transfer from a heated cylinder in cylinders array (due to embedding it in a porous medium) was nearly five times the heat that transferred from the same free cylinders array or arrangement at the same flow velocity depending on available data from preceding experimental study.

An experimental study on natural convection heat transfer across an eccentric horizontal annulus under the condition of constant surface temperature was carried out. The study included clarifying the effect of eccentricity ratio and the angular position as well as the effect of Raleigh number on the ability of the inner cylinder to heat reject. An experimental set-up was done for this purpose which consists of a cooling water tank and two aluminum cylinders, the outer diameter of the inner cylinder is(26mm), electrically heated from the inside, which represents the heating element, the inner diameter of the outer cylinder is(100mm) which represent cooling element in this set-up. The experimental study showed that the ability of the inner cylinder to transmit heat with free convection is a function to eccentricity ratio and the angular position, as well as Raleigh number, where this ability increases as angular position increases for all eccentricity ratios, while the eccentricity ratio effect depends on the angular position, where the thermal performance for the inner cylinder may be better at the location (δ=180o) for the ratio (ε=0.2), where the maximum enhancement in heat transfer coefficient was recorded as(10%) at this location in comparison with concentric annulus, whilst the location (δ=0o)for the ratio (ε=0.726) was given maximum reduction in heat transfer coefficient for the inner cylinder was recorded as (23%) in comparison with concentric annulus, whilst the coefficient of heat transfer proportional directly with Raleigh number.

In this study ferrous sulfate had been used as an oxidant for removing the sulfide from water samples taken from sulfide spring in Hamam al-alil south of the Mosul city. The study revealed that ferrous sulfate is efficient in removing sulfide in dose not to exceed to 200mg/l with an efficiency of 77%, also adding of Bentonite clay with ferrous sulfate in a dose of 150mg/l and eliminate the black color due to addition of ferrous sulfate, However; Bentonite clay is inefficient in removing sulfide from the water with dose more than 300mg/l, also the study revealed that the use of Bentonite clay alone or with ferrous sulfate reduce the turbidity of treated water with efficiency more than 89%.