Research On Biofouling Growth Dynamics In The Circulating Cooling Water System

The circulating cooling water is in high percentage in the petroleum industry development. If we reuse refinery wastewater after advanced treatment as circulating cooling water, it has important significance for energy conservstion and emission reduction and sustainable development. But at the same time, because refinery wastewater has more organism and ions in both kind and number, the number of the biofouling produce more.In view of the characteristics of circulating cooling water system, the static experiment was designed to culture the biofouling formation by timing drain concentration. The growth curve of the biofouling was made and the development mechanism was discussed through record the biofouling growth. Through a series of single factor experiments, the different influences of nutrient substances, tempreture and the shear force of flow on biofouling growth were investigated, respectively. Then in accordance with the previous experimental results, the appropriate biofouling growth dynamic equation was selected and transformed.Carbon was the most influencing factor for the wet weight, the organic matter and the viable cell of the biofouling. If there is enough phosphorus and nitrogen, the adapting period of the biofouling would short, the maximum growth rate would rise in the period of logarithmic growth, and the wet weight, the organic matter and the viable cell of the biofouling would increase along with the increase of carbon source. But at the same time, because the biofouling grow fast, the space structure are loose, and the shedding situtation was obviously when the biofouling were in the stationary phase.The nutrient substances and the shear force of flow had more influences than tempreture. The flow enhance nutriment and oxygen mass transfer for the biofouling, but it cause the shear force simultaneously, and the influences of the shear force was more obviously. The factor of tempreture influenced the enzymatic activity of the biofouling. The activity of microorganism was highest and the biofouling growth was eugonicest in moderate tempreture.The microorganism, which was in the biofouling, had different population structure in different nutrient substances levels. But in the same level, the population structure of the biofouling was similar in different period, and the difference consist in the number only.We selected and used the Logistic model as instructional model, and we made the model more intuitionstic and accurate through the model transformed. The model could react the process of the shedding and the regeneration well when the biofouling grow into stationary phase. The actual application ability of the model raised.