ABSTRACT
With respect to an increasing growth in city population and also an annual increase in the per capita consumption in the societies, particularly in the dry and semi-dry countries, the opportunity to use surface water sources to provide drinking water for the cities has decreased. In a such way, in 2001 more than 70 percent of the drinking water for the population of Tehran had been provided by underground water sources due to a decrease in the water reservoirs of Latian, Karag and Lar dam. The figure shows an increase for other cities of Iran as well. On the other hand, due to discharging industrial sewages with chrome and nickel contents in the absorptive wells and the penetration potentials of these compounds into underground waters, and with respect to the potential of these substances to accumulate in different tissues of the body and their sarcoma-generation characteristics as proved through various researches a strong need is felt to render a careful control on these sources. In this research, the plan is to omit and remove chrome and nickel from the sewage polluted underground water sources by using the essence of oak tree fruit for their condensed tannic acid, hydrolysable tannic acid, gaelic acid and Eeagic acid contents. First 60 water samples with a given amount of chrome and nickel contents were prepared and divided into 12 different groups with 5 concentration and environmental conditions. The experimental and non-probable sampling were applied sample taking and the counter effects of Tannin essence. Calcium hydroxide and sodium hydroxide were studied both in separated and simultaneous forms. With respect to the given initial concentration, the amount of remaining concentration was determined by flame application at the atomic absorption device. Among the measured specimen, 50 mg/1 of concentration of calcium hydroxide or 50 mg/1 of concentration of sodium hydroxide along with 50 mg/1 tannin-content essence with 80 to 86 percent output proved to render best conditions in omitting chrome and nickel from reaction environment. The results were evaluated through bi-factors variance analysis with one repletion in each box tests to ensure the accuracy and care rendered in performing the test. The results showed that simultaneous application of two chilling factors found in calcium hydroxide and tannin essence show significant differences as compared with other methods and also it was proved that the tannin content essence in an alkaline environment forms a full set of [OH] branches that are bound with chrome and nickel ions in the reaction environmental and due to the large size of tannin molecules and their saturation with the existing cations, they form a flocc mass that immediately deposits for its heavy weight. Also the essence in the tannin is able to take the mentioned ions form the reaction environment both in low and large concentrates and the ions concentrations have no significant differences in omission output