Full-Scale Experimental Research On Preceding Treatment For Tannery Wastewater From The City Of Tannery In Zhao Yuan

As early as 20 century 90 years, the development of leather industry is swift, which has been the mainstay of the light industry. The development of the leather industry makes the market flourishing, and brings wealth to the nation. Still, the environment is also contaminated severely. So, it is an important question that how to make the leather industry clean and civilied, and to keep the development of economy and environment continuable, and to make the harmonious development among humanbeing, society and environment.In this paper, the effect of the remove of sulfide in leather industry waste water was observed through the catalyse oxidation method, and the concentration of the sulfide and the addition of MnSO4 for catalyzer to the effect was observed. The problems occurred in the project was analysed, and some acceptable suggestion was given accordingly. The harm was pointed out if the waste water was not let off by diffluence.A systemic research was performed to study several coagulants in this paper. PAC, FeCl₃ and FeSO₄ was adopted as coagulant respectively or combined with PAM as coagulant aid, in order to study the effect of coagulant in leather industry waste water. At low temperature, the experiment is to study the influence of coagulation by coagulant dosage and pH, and the influence of pH by coagulant dosage in treated water. The most appropriate range of coagulant dosage and pH for treating waste water of leather industry was ascertained respectively as well as the PAM dosage. Further more, according to the result, the kind of coagulant and coagulant dosage used in practice of the project was ascertained.The different problems were summarized in the waste water treatment plant during the debugging, and some suggestion was given accordingly. It accordingly provides credible reference to the run and administration, design and construction for the future. It shows that the inclined plate settling and air flotation have good capability to resist the impact of hydraulic and organic compound load. The inlet flux is at low level during the debugging that it is only half of the one designed, so the reflux ratio of air flotation is high. It is given as suggestion to increase the inlet flux, in order to decrease the total run time and energy. The approximate pressure range of dissolved air vessel is about 400⁴50kp, so that it gets better removal effect for dissolved-air flotation.When the inlet concentration of COD and SS were respectively in range of 400³800 mg/L and 1500²500mg/L, the total removal efficiency of COD and SS by coagulant sedimentation and air flotation is approximately 50% and 90%.So, it can ensure the biological treatment run steadily on high removal efficiency, and assure the leather industry waste water let off according with first-degree standard.