The purpose of this study is to apply a hybrid process that combines the precipitation with hydrate lime along with reverse osmosis (RO) treatment to deal with a real industrial wastewater having an excessive fluoride concentration of 3,200 mg/L. The effluent is discharged from an aluminum fluoride manufacturing unit. Neutralization with hydrated lime using excesses above 50% at pH 7–8 led to fluoride removal rates higher than 98%. The industrial effluent neutralized under optimal conditions underwent an RO treatment that allowed to reduce the fluoride content to about 8 mg/L giving an overall removal of 99.9% F⁻. This study demonstrated that the hybrid precipitation–RO process could effectively remove fluoride from wastewater, and produce permeate and precipitates for potential recovery and reuse.

The complexity of Activated Sludge Model No. 1 (ASM1) is one of the main obstacles slowing its widespread use, particularly among wastewater treatment plant (WWTP) professionals. In this paper, a simplification procedure based on steady-state mass balances is proposed for the conventional activated sludge process (ASP) configuration, consisting of an aerated bioreactor and a perfect settler (without particular compounds in the outlet). The results do, in fact, show perfect suitability to a membrane bioreactor process (MBR). Both organic carbon and nitrogen removal were investigated. The proposed approach was applied to ASM1, and simple analytical expressions of the state variables were obtained. These analytical expressions were then validated by comparison to simulations given by the original ASM1 (implemented in GPS-X software). A strong match (less than 4% of error overall) was obtained between both results in the steady-state; consequently, these analytical expressions may be useful as tools for quickly estimating the main state variables, feeding the filtration models, or identifying the interaction between operating parameters. Moreover, this enables a sensitivity analysis, covering relevant factors such as kinetics or operating parameters. For instance, the sludge retention time (SRT) effect is lower on X_BH and X_S at high SRT (˃20 days), while it is more pronounced on X_P and X_I as their variations with SRT are linear.

The objectives of the present investigation are to study the interaction and optimize the blend composition of flour of grinded Chia seeds, combined to Soy lecithin, a bread making improver, in a way to enhance the nutritional/functional value of bread without impairing its technological quality and to delay its staling rate. Nine formulations were prepared following a Central Composite Design. Technological attributes were evaluated both for fresh and stored bread. In the Response Surface Methodology (RSM) a desirability function identified the optimum doses of chia and lecithin incorporation to obtain the highest specific volume and the lowest crumb firmness. Compared to the control, samples with chia and lecithin significantly increased the nutritional value of bread. An innovative and interesting synergy was found in lecithin/chia combination to enhance the specific volume, to reduce the initial crumb firmness and to delay bread staling by retarding crumb firmness and reducing its water loss during storage. Using the RSM, the optimum blend containing (4.04%-Chia/1%-Lecithin) showed fresh bread with maximum specific volume and minimum crumb firmness. Whereas, bread combining the optimum blend (3.43%-Chia/1%-Lecithin) and stored for two days at room temperature showed the minimum crumb firmness.

A mathematical model was developed to predict super saturation along reverse osmosis modules (RO) for water desalination. This model is based on conservation principles and chemical equilibrium equations for concentrated solutions. Pitzer’s model was used for the activity coefficient calculations. An average rejection rate for each ionic species was also considered. Supersaturations with respect to all calcium carbonate forms and to calcium sulfate are calculated. The model allows assessing when scale is likely to occur along the RO modules. The results for two brackish water qualities and seawater are shown.

Wastewater reuse in agriculture in the outskirts of the city Batna (Algeria)