Investigation of Membrane Fouling in Vacuum Membrane Distillation (VMD) Using Blocking Filtration Laws

VMD is one of the desalination technologies used for drinking water purification because of it higher permeate flux and lower energy consumption, and it uses low grade energy for operation. However, there are some critical problems related to VMD, one of which is membrane fouling. In the present study, the fouling phenomenon in VMD is investigated using constant pressure-blocking filtration laws. The results of constant pressure-blocking filtration law indicated that the permeate flux was initially unaffected by the cake layer, but with the passage of time as the pores began to constrict, a formation of a relatively thick cake layer was observed, which resulted in the decrease of permeate flux.

Rationale for the use of photocatalysis for natural and drinking water purification from pollutants of biological origin

Objective. To evaluate the effectiveness of photocatalytic methods of oxidation of organic substances for the preparation of drinking water. To show the expediency of the use of the described method for the design of wastewater treatment facilities.Materials and methods. The oxidation degrees of 58 organic substances of various hazard classes were studied. The sampling frame was based on two characteristics: origin (biological and artificial) and the oxidation state stated in different sources.Results. A high efficiency of photocatalysis for the destruction of organic substances in wastewater from various industries has been shown: the degrees of oxidation range from 70 to 100 %.Conclusion. Photocatalysis can be used to design wastewater treatment facilities with a view to reducing the probability of biological pollution of natural waters intended for drinking water production.

Developing Magnetic Material for Remediation of Aquatic Nitrogen Pollution in Water Facilities

Natural organic matter affect water environmental security and posed a potential threat to human health, and thus it has long been considered as a key index to evaluate water treatment performance. Dissolved organic nitrogen is one of the NOM, which produces some disinfection byproducts having more toxic than those carbon-based materials. Coagulation is a key unit of drinking water purification and has received wide attention. However, conventional flocculation technology on removal of DON is so poor that we have to seek more effective improving measurement. The combined use of conventional flocculant and organic polymer can improve treatment efficiency to a certain extent, and enhanced coagulation can also improve the DON removal rate, but their DON removal performance is still not dreamful. At present, there is a lack of systematic research on flocculation to remove DON. Although some achievements have been made, there is still a big gap between the preparation technology of flocculant and the goal of efficient removal of DON in water.For treatment of secondary effluent of industrial wastewater, some studies show that the use of Fe3O4 mainly has the effect of accelerating separation, but the adsorption effect is not good. However, with the synergistic flocculation of amino functionalized Fe3O4 it has a good effect on removing water protein, polysaccharide and humic acid, which can meet the water quality discharge standard and reduce the dosage of flocculant. The above results show that functional nanoparticle materials are of great significance to improve the adsorption and flocculation performance. Therefore, the functional modification of magnetic nanoparticles plays an important role.

Research on drinking water purification technologies for household use by reducing total dissolved solids (TDS)

This study, based in San Bernardino County, Southern California, collected and examined tap water samples within the area to explore the feasibility of adopting non-industrial equipment and methods to reduce water hardness and total dissolved solids(TDS). We investigated how water quality could be improved by utilizing water boiling, activated carbon and sodium bicarbonate additives, as well as electrolysis methods. The results show that heating is effective at lower temperatures rather than long boils, as none of the boiling tests were lower than the original value. Activated carbon is unable to lower TDS, because it is unable to bind to any impurities present in the water. This resulted in an overall TDS increase of 3.5%. However, adding small amounts of sodium bicarbonate(NaHCO3) will further eliminate water hardness by reacting with magnesium ions and improve taste, while increasing the pH. When added to room temperature tap water, there is a continuous increase in TDS of 24.8% at the 30 mg/L mark. The new findings presented in this study showed that electrolysis was the most successful method in eliminating TDS, showing an inverse proportion where an increasing electrical current and duration of electrical lowers more amounts of solids. This method created a maximum decrease in TDS by a maximum of 22.7%, with 3 tests resulting in 15.3–16.6% decreases. Furthermore, when water is heated to a temperature around 50°C (122°F), a decrease in TDS of around 16% was also shown. The reduction of these solids will help lower water hardness and improve the taste of tap water. These results will help direct residents to drink more tap water rather than bottled water with similar taste and health benefits for a cheaper price as well as a reduction on plastic usage.

Performance Improvement of Solar Still with and without Use of PCM

Water problems are same in worldwide. Mainly it is faces by rural area peoples. Mostly drinking water is available from wells and rivers. Because of high population and industrialisation this water might be contaminated with harmful substances such as bacteria and therefore unsafe drinking water. Purification of water by solar is most useful and economic and safe solution. Solar still are mostly useful in rural and tribal area to provide clean water. Solar water still easy to construct, output depend on type of model. And it is operated by unskilled person easily no hard maintenance required and no operational cost and are also clean and safe process and no any type of pollution spread by this process. In this experimentation work comparison is to be made between with and without use of phase change material. It is observed that use of latent storage in solar still will increase water output.