Effect of influent temperature on determination of airflow at doyang sewage treatment plant

To construct an energy saving airflow-controlling system for Doyang sewage treatment plant, the factors affecting airflow of the influent was analyzed in this study. This research analyzed the operation data of Doyang sewage treatment plant for 912 days. As a result, the key factors deciding the optimum airflow were found to be temperature, F/M ratio, the loading rate of BOD5 and T-N of the influent. Among the factors, the temperature of the influent had the most decisive effect on the aeration volume. The result showed that an increase of 1 °C of the influent requires 45.3 m3/h airflow. Since the factors affected by seasons like flow rate, F/M ratio and MLSS affect airflow required of blowers, and the change of temperature is considered to intensify the change of airflow even more. Therefore, it is preferable to consider flow rate, F/M ratio, MLSS and water temperature altogether than considering only one factor when deciding airflow of blowers. The results of this research can be utilized as indicators when designing energy saving system for sewage treatment plants.

A Mixed Denoising Method Based on Median Filter and Lifting Wavelet Technology for Sewage Sensing Signal Treatment

Digital signals are often contaminated by noise during signal acquisition and transmission for sewage sensing signal treatment such as aeration volume, oxygen content and water transparency etc. Sometimes, noise is a mixed one of gaussian noise and impulse noise. Unfortunately, existing denoising algorithms are often designed for removing single gaussian noise or impulse noise. In this paper, an efficient algorithm for mixed noise removal in signal is proposed, including space impulse noise removal and wavelet Gaussian noise removal. An impulse noise detection algorithm based on median filter is given to filter impulse signal, also a lifting wavelet was constructed by lifting original wavelet. The threshold based on lifting wavelet transform for signal was applied to denoising gaussian noise. Simulations are conducted on the presented algorithm, and the simulation result shows that this algorithm can remove mixed Gaussian and impulse noise in signal efficiently.

Study on the Sewage Treatment by SBBR-BAF Filled with Ceramic Filling

In the biological aerated filter, the removal efficiency of phosphorus is poor, while the efficiency of organics and nitrogen are very well. In order to solve these problems, the sequence bio-film reactor connects to traditional biological aerated filter, ceramic filler was added to the system, study the effect of bio-film culturing and biological disposal capacity .Control intermittent time of anaerobic and aerobic and aeration volume, the removal effect of COD 、nitrogen and phosphorus are good in the sewage . The results show that anaerobic and aerated time are 3h and 4h in SBBR, the removal efficiency of COD、NH4+-N、TN and TP are 90.07%、85.12%、81.74% and 83.63%, the concentration are 31.37mg/L, 5.15㎎/L, 6.60㎎/L and 1.10㎎/L separately. All of these satisfy theⅠ-B criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). The system of SBBR-BAF run stably, removal sewage perfectly, avoid return and mud, save energy consumption.