Treatment Of Tannery Wastewater By Combined Process Of Two-stage H/O And Ecological Pond: Study And Practice

With the development of Curriery industry, the problems such as water consumption and wastetwater discharge became more serious, and one of the most unmanageable pollutant was NH3-N. This work studied the treatment of tannery wastewater by combined process of two-stage H/O and ecological pond, searching start-up method and running Characteristics of this process were investigated. The effect of environmental factors, operation parameters on pollutants removal was also researched. Based on these works, an engineering project was performed and the practical effect of tannery wastewater by combined process of two-stage H/O and ecological pond was obtained. The main results were as follows:1. The Process started up by the method of feeding and culture.3 weeks of operation showed that the sludge grows well and that there moving rate of COD was above 30% in hydrolytic tank,70% in oxidation tank.2. The optimal retention time of the first hydraulic tank was 12h, such as 20h in the first oxidation tank. The optimal retention time of the second hydraulic tank was also 12h, in this condition, the removal rate of COD and ammonia nitrogen could achieve 31.2% and 34.6% by the second H/O tank.3. The optimal hydraulic surface loading of ecological pond was 0.017m3/m2·h, in this condition, the removal rate of COD and ammonia nitrogen could achieve 46.1% and 360%.4. Monitoring along the system showed DO and pH maintaining stability, the highest COD and ammonia nitrogen removal was in the first H/O tank.5. Based on the experiment results, a project was designed for tannery waterwater treatment with a water quantity of 5000m3/d. The system showed fine ability on the wastewater advaced treament, and the effuent qualiity meets the requirement of diseharge standard for wastewater.