No abstract

Reverse Osmosis (RO) has already proved its worth as an efficient treatment method in chemical and environmental engineering applications. Various successful RO attempts for the rejection of organic and highly toxic pollutants from wastewater can be found in the literature over the last decade. Dimethylphenol is classified as a high-toxic organic compound found ubiquitously in wastewater. It poses a real threat to humans and the environment even at low concentration. In this paper, a model based framework was developed for the simulation and optimisation of RO process for the removal of dimethylphenol from wastewater. We incorporated our earlier developed and validated process model into the Species Conserving Genetic Algorithm (SCGA) based optimisation framework to optimise the design and operational parameters of the process. To provide a deeper insight of the process to the readers, the influences of membrane design parameters on dimethylphenol rejection, water recovery rate and the level of specific energy consumption of the process for two different sets of operating conditions are presented first which were achieved via simulation. The membrane parameters taken into consideration include membrane length, width and feed channel height. Finally, a multi-objective function is presented to optimise the membrane design parameters, dimethylphenol rejection and required energy consumption. Simulation results affirmed insignificant and significant impacts of membrane length and width on dimethylphenol rejection and specific energy consumption, respectively. However, these performance indicators are negatively influenced due to increasing the feed channel height. On the other hand, optimisation results generated an optimum removal of dimethylphenol at reduced specific energy consumption for a wide sets of inlet conditions. More importantly, the dimethylphenol rejection increased by around 2.51% to 98.72% compared to ordinary RO module measurements with a saving of around 20.6% of specific energy consumption.

Use of computer simulation to quantify the effectiveness of blowing agents can be an effective tool for optimizing formulations and for the adopting of new blowing agents. This paper focuses on a mass balance on blowing agent during foaming including the quantification of the amount that stays in the resin, the amount that ends up in the foam cells, and the pressure of the blowing agent in the foam cells. Experimental data is presented both in the sense of developing the simulation capabilities and the validating of simulation results.

<p><strong>Abstract.</strong> Shock chlorination is a well-known practice in swimming pools and domestic wells. One of the limitations for using this technique in drinking water purification facilities is the difficulty of quickly removing high chlorine concentrations in water distribution systems or production facilities. In order to use this method in the drinking water industry a shock de-chlorination method should be introduced for producing microorganism and biocide free water. De-chlorination using natural stagnant aeration (leaving the water to lose the chlorine naturally) is the safest known method if compared with chemical and charcoaling methods. Unfortunately, stagnant aeration is a slow process. Therefore, developing a process for accelerating de-chlorination by aeration would pave the way for using shock de-chlorination in drinking water industry.</p> <p>Forced air bubbling is a possible technique for de-chlorination but there is lack of data supporting such a process. The theory is that air bubbling has the advantages of higher mass transfer area, higher Reynolds number across the bubble water interface, and higher mass transfer concentration gradient as the bubbling presents a continuous stream of fresh bubbles. All of these factors accelerate aeration to various extents.</p> <p>A 20 cm diameter, 1-meter height column provided with air sparger was designed to collect the desired data used in this study. Trichloroisocyanuric acid, sodium hypochlorite and chlorine gas were the three familiar sources of chlorine used to investigate their response to air bubbling.</p> <p>Chlorine gas was the fastest and safest chlorine source to be dechlorinated. It dropped from 200 ppm to 0.02 ppm within 4 minutes or zero ppm within 6 minutes using an air flowrate of 9 l/min.</p> <p>Sodium hypochlorite decreased from 200 ppm to 0.02 ppm within 6 minutes using air flowrate of 9 l/min. Trichloroisocyanuric acid found to be the chlorine source slowest to respond to de-chlorination. It decreased from 200 ppm to 0.02 ppm within 8 minutes using an air flowrate of 9 l/min.</p> <p>Shock de-chlorination by aeration is found to be a promising method that opens up the drinking water industry and could produce microorganism and biocide free drinking water.</p>

This study was conducted in research department of animal resource/ Al-Rashidiya, at ministry of agriculture by using 14 of genetically improved awassi ewes, average body weight 56.00 ± 2.10 kg and age ranged between 3-5 years. Ewes were allocated according to their weight and milk production into two groups. The first was control (T1), fed on ration consist mainly of untreated barley and contain 9.69% of degradable protein and 3.77% of undegradable protein as dry matter. The second group (T2) was fed on same control ration but barley grain were treated with formaldehyde and contain 9.63% degradable protein and 6.37% of undegradable protein as dry