Additional Purification of Waste Water after Conventional Waste Treatment in Plating Industry
Equilibrium and kinetic parameters of sorption of cations of metals and ammonium from rinse water by natural zeolites were determined. Selectivity of zeolites for following cations was established:<i> NH</i><sub><i>4 </i></sub><i>> Cu > Zn > Ni</i>. The calculations of protection time of a sorbent layer and the of a sorption filter for Ni ions for real conditions were made. The regional raw material - natural zeolites of the Muhor-Talinsky deposit of the Republic of Buryatia has been applied as a sorbent. Selected and fractioned zeolites samples with grain of 1-5 mm in diameter were of klinoptillolit-mordenite nature. Cations concentrations in the rinse water after conventional treatment were equal to (mmol/dm<sup>3</sup>): <i>Cu</i><sup><i>2+</i></sup><i></i> - 0.128; <i>Ni</i><sup><i>2+</i> </sup>- 0.112; <i>Zn</i><sup><i>2+</i></sup><i></i> - 0.068 and <i>NH</i><sub><i>4</i></sub><sup><i>+</i></sup><i></i> - 0.354, and overall concentration of macrocations <i>Ca</i><sup><i>2+</i></sup><i>, Mg</i><sup><i>2+</i></sup><i>, Na</i><sup><i>+</i></sup><i>, K</i><sup><i></i>+</sup>,<i>Fe</i><sup><i></i>3+</sup> was equal to - 3.5. Experiments were made with model solutions and real waste water of «Instrument-Making Association», Ulan-Ude. Calculations were based on Ni ions as less sorbable. Determination of equilibrium and kinetic parameters of sorption was conducted for the experimental data of the static (figure 1) and dynamic (figure 2) tests. The calculation of life time of the sorption filter was made for the residual concentration not exceeding its limiting value. According to our investigations the efficiency of additional sorption treatment meets the requirements for the recycling of rinse water as well as those for the disposal into a city sewer system (table 2). The recycling of purified water allows to reduce the consumption of fresh water, the amount of disposed water, and the consumption of reagents.