Pilot Experiment Of SMBBR Treating Electroplating Wastewater From Biochemical Process And Economic Benefit Analysis

Electroplating wastewater has wide sources and poor biodegradability.At the same time,it has the characteristics of toxicity,high salinity,obvious chromaticity and complex composition.The effective treatment of electroplating wastewater has attracted much attention because a large amount of electroplating wastewater will cause great damage to the natural environment and greatly affect human health.In accordance with the requirements of the electroplating park,the S/AF/S/AMBBR combination process was designed to treat wastewater for meeting the environmental quality standard for Class IV surface water arear.SMBBR process is a new process with patent technology.Compared with traditional fluidized bed technology,it has the following advantages:?1?the design scheme of carrier is advanced that biological carrier has large specific surface area,and stronger hydrophilicity;?2?SDC-Y11,a specific bacteria,was added at the start-up stage which favor biofilm culturing rapidly.After comprehensive consideration,the SMBBR and AMBBR devices were adopted biofilm culturing process combined with draw-off sludge and batch culture with gradually increase the influential load,while AF devices was adopted natural inoculation process.In the process of starting the hanging film,good external conditions for biofilm culturing was provided by controlling the external influencing factors such as water temperature,pH and salt.The biofilm culturing reactor was marked off into three phases:adaptive phase,logarithmic phase,linear phase and stable phase.Through the observation and analysis of the biological phase,it was found that the microbial biomass on the surface of biological carrier was large,which played a decisive role in the treatment of sewage in the stable period after the successful biofilm culturing in the later stage.In the process of biofilm culturing,the removal effect of ammonia nitrogen and COD was not increased synchronously.S/AF/S/AMBBR combined process had better treatment effect on COD,NH₃-N,TN and TP.In the stable operation stage,the S/AF/S/AMBBR combined process had good treatment effect on COD,NH₃-N,TN and TP.The effluent can reach the environmental quality standard for Class IV surface water arear stably when the carbon source dosage was120mg/L,the hydraulic retention time was 3d,and the filling rate was 50%.During the stable operation,the system had a high removal efficiency,almost 100%,for all heavy metal pollutants in the raw water.The amount of added carbon source directly affected the concentration of TN in effluent.With the increase of added carbon source,the removal rate of TN gradually increased.In order to ensure that the concentration of other indicators in effluent meets the emission standard and operation economy,the amount of added carbon source?ethanol?should be 120mg/L.With the increase of hydraulic retention time,the removal rate of TN first increased and then decreased.When the filling rate of fillers was50%,the carbon source dosage was 120mg/L,and the hydraulic retention time was 3d,the removal rate of TN was the highest.According to the economic analysis,the unit price for 1 m³ wastewater treated by S/AF/S/AMBBR process with reaching the standard was 1.36 yuan that was lower than the original process.And this process was suitable for the transformation process of the electroplating park with a small area,simple operation,high additional social and environmental benefits.