Search

Drinking water contamination by fluoride component (F-) is considered as a main public problem in Basra city. The current study highlights on the removal of (F-) from drinking water using effective and low cost materials namely, banana shell and new technical that prepared from orange shell loaded with Zirconyl chloride solutions (Z-r4 (O-H)8 (H2-O)16] Cl8 (H2-O)12) to develop active adsorption sites for fluoride . High removal efficiency of 94.4 was achieved using fixed bed column loaded (Zc-dejr) under optimum operating conditions, 15.1 ppm of feed concentration, 4.5 pH of feed solution and 4 cm of bed depth. Result of breakthrough profile showed that Thomas was coincided well with the experimental data. Two model, Pseude first order and Pseudo second order where used for finding the mechanism of adsorption kinetics for fluoride (F-) removal by two-bio adsorbents. The result showed that the external adsorption besides to the intra-particle diffusion contributes to the rate influential step. Lagmaier model gives the better result model for the two adsorbents then Temkin isotherm model (TIM). The final concentration of fluoride in treated water with the banana shell adsorbent was 1 mg/l, and with the new solution (Z-r4 (O-H)8(H2-O)16] Cl8 (H2-O)12 ) was 0.5 mg /l which is acceptable with the standard World Health Organization (WHO). http://dx.doi.org/10.30572/2018/kje/090301

Petroleum hydrocarbons contaminants of groundwater are the one of the most difficult environmental problem in oil producing in the south of Iraq especially Basra City. Numerous regions in the south of Iraq had been utilized for agriculture which depending on ground waters. Thus, the petroleum hydrocarbons contaminants will effect on these projects. Benzene, toluene, and dimethylbenzene are the most toxic pollutants effects on chlorine removal of perchloroethene (Cl2C=CCl2) and trichloroethene (C2HCl3) the groundwater. These pollutants have high solubility in water that led to transport to a long distance in groundwater and difficult removal. The influence of petroleum hydrocarbons on the chlorine removal of (Cl2C=CCl2) and C2HCl3) was studied in this paper using polytetrafluoroethylene column packed with zero-valent-iron (ZVI). Batch experiments were implemented to investigate the equilibrium supply of mixtures between aqueous and solid stages in packed column systems. It was designated using Freundlich isotherm expression where the result showed that R2 greater than 0.97 for all of benzene, toluene, and xylene. Column study noted that the reaction constant is decreased in all column by about 48 % and clearly when the pore volume between (50-205) that reflects the de-chlorination priority of P-CE rather than T-CE. The result shows that benzene and toluene is more effective for adsorption on the zero-valent-iron particle surface owing to the disparate influences.

The paper presents a study correlating the profile of on-line monitoring parameters and off-line measurement of nutrient concentrations (NH4 +-N, TN, NO3 −-N and TP) in a novel technology phased isolation tank step feed (PITSF) system, thereby utilizing the parameters as economical operational tool. A fixed-time control study showed that real control points (RCPs) on pH and oxidation-reduction potential (ORP) profiles accurately coincided with the major biological activities, whereas both DO and pH profiles are applied to control the end of nitrification and phosphate uptake process in aerobic phases, in particular, the “ammonia valley” on the pH profile for nitrification process. The analysis of the first aerobic tanks during the main phases showed that the RCP on DO profile can be used to distinguish the occurrence of simultaneous denitrification and nitrification (SND). Both the RCPs on the ORP profile and “nitrate apex” on the pH profile are applied to control the end of denitrification. The relationship between ORP and phosphorus release is linear and both (dORP/dt) and (dpH/dt) values are applied to control the end of anaerobic phosphorus release. Therefore, a new, reliable and effective real-time control strategy was developed using DO, pH and ORP as control parameters, to improve the performance of the PITSF process. As a final engineering observation, the proposed system is regarded as an effective process because the PITSF system can be operated safely under intercross real time control to treat low C/N domestic wastewater. The total nutrient removal efficiencies of COD, TN, NH4 +-N, and TP with low C/N ratio and normal water temperature of (17–21) °C were 91.7, 83.2, 95.7 and 92.1%, respectively, which was approximately equal to the complete nitrification-denitrification with the addition of external carbon sources under low water temperature of (8–11) °C.

In this study, an anaerobic–anoxic/oxic (A2/O) multiphased biological process called “phased isolation tank step feed technology of southeast university (PITSF-SEU)” was developed to force the oscillation of organic and nutrient concentrations in process reactors. PITSF reactor is effective for reducing energy consumption because it does not contain the internal recycle of mixed liquor and sludge return device. A computer program was built based on mass balance equations on each tank using an extension activated sludge model for simulating the soluble and particulate compounds in each tank of PITSF-SEU system. The considerable differences between the extension model and other models are two stage for nitrification process and multistage for denitrification process. Also, phosphorus removal was taken into account simultaneously in this model. The difficulty of model simulation is coming from the system operation with unsteady-state condition and the changing of multipoint step feed location with it...

A novel technology was developed to achieve partial nitrification at moderately low DO and short HRT, which would save the aeration cost and have the capacity to treat a wide range of low-strength real wastewater. The process enables a relatively stable whereas nitrite accumulation rate (NO2-AR) was stabilized over 94% in the last aerobic basin on average of each phase through a combination of short HRT and low DO level. Low DO did not produce sludge with poorer settleability. The morphology and internal structure of the granular sludge was observed by using a scanning electron microscope (SEM) analysis during a long-term operation. The images indicated that thick clusters of spherical cells and small rod-shaped cells (NOB and AOB are rod-shaped to spherical cells) were the dominant population structure, rather than filamentous and other bacteria under a combination of low DO and short HRT, which gives a good indication of nitrite accumulation achievement. MPN method was used to correlate AOB numbers with nutrient removal. It showed that an ammonia-oxidizing bacterium (AOB) was the dominant nitrifying bacteria, whereas high NO2-AR was achieved at AOB number of 5.33×108 cell/g MLSS. Higher pollutant removal efficiency of 86.2%, 98% and 96.1%, for TN, NH4+-N, and TP, respectively, was achieved by a novel six basin activated sludge process (SBASP) at low DO level and low C/N ratio which were approximately equal to the complete nitrification-denitrification with the addition of sodium acetate (NaAc) at normal DO level of (1.5–2.5 mg/L).

Approach: Backwashing process was implemented using column of deep bed filter with different media characteristics to provide optimal operation condition. Minimum velocity of fluidization (V mf) and porosity at minimum fluidization (e mf) were investigated under different operation condition and grains size. The results were compared with Wen and Yu equation and Richardson–Zaki correlation, respectively. Backwashing model was developed to predict the effect of fluid shear strength (τ a), velocity grade (G), dissipation rate coefficient (C a), and parameters of random motion ( /Re) on the energy dissipation rate during fluidization process. Results: The simulated result of proposed models gives a good convergence to observed data. It was seen that a smaller size of sand media need a lower value of backwash velocity than a higher size for lifting filter media. Fixed bed porosity increased from 0.510 to 0.704 at bigger size of sand media (1.18 mm), while it increased to 0.680 at smaller size of sand...

The performance of a new pilot-scale six tanks activated sludge process has been evaluated for 303 d, receiving real domestic wastewater with a flow rate of 15-24.4 L/h. Partial nitrification via nitrite and microbial community structure were investigated in this system. The result shows that the nitrite accumulation rate was achieved successfully over 94% in the last aerobic compartment through a combination of short hydraulic retention time and low dissolved oxygen (DO) level. Fluorescence in situ hybridization analysis was used to correlate ammonia-oxidizing bacteria (AOB) numbers with nutrient removal via nitrite. It was shown that in response to complete and partial nitrification modes, the numbers of AOB population were 7.7 x 10(7) cells/g mixed liquor suspended solids (MLSS) and 5.31 x 10(8) cells/g MLSS, respectively. The morphology of the sludge indicated that there is a small rod-shaped and spherical cluster which was mainly dominantly bacterial according to scanning electron microscope. Higher pollutant removal efficiencies of 86.2%, 98%, and 96.1%, for total nitrogen, NH4+ - N, and total phosphorus, respectively, were achieved by a long-term operation of the six tanks activated sludge process at a low DO concentration and low chemical oxygen demand to nitrogen ratio which were approximately equal to the complete nitrification-ldenitrification with the addition of an external carbon source at a concentration of 1.5-2.5 mg/L.