Study Of Biodegradable Dissolved Organic Carbon Change In Water Distribution System

Drinking water is closely linked to our living level and our health, so the influence of drinking water quality on health is being the focus in the drinking water research field. Many researchers found that, even keeping a certain level of residual chlorine, the heterotrophic bacteria re-growth if there are organic matters in water. So researchers pay attention to the bio-stability of drinking water more and more. Biodegradable dissolved organic carbon (BDOC) is a very important influent faction on the bio-stability of drinking water, which received the widespread attention.The article chose a certain university campus pipe as the region for water quality research after careful investigation of the actual condition. Based on the pipe material, the pipe water inlet, the pipe water end and other factors, it selected 7 typical detection points in the campus. Chose 7 water quality targets following as: free residue chlorine, temperature, pH, turbidity, iron, TOC and BDOC. The concrete experiment includes: the confirmation of the changing rule of conventional water quality and their inter-relationships; the evaluation of the water quality; the statistical analysis of the water quality which affects BDOC, the judgment of the biological stability in the pipe network; the bringing of forward BDOC forecast models by the multi-dimensional linearity regression method, the principal components regression method and neural network (BP); the getting of the best model after examination through the measured data.Through the analysis of the conventional water quality, we can get that the campus scope has a good disinfection of water supply. And the turbidity in the end of the pipe is lower than that of the entry point and midway. The density of iron is in proportion to the turbidity, which exceeding the allowed figure seriously. The TOC level is very high (according to the CJ94-1999 standard), exceeding the allowed figure rate 71.43%.The article also made a statistical analysis on the BDOC examination by the Statistical Package for Social Science (SPSS) software. Judging from the long-term examination result, it fined that: free residue chlorine is in inverse proportion with BDOC; but the turbidity is in strong proportion with the BDOC; monthly average TOC is relevant with the BDOC strongly.All the three models are based on the statistical data. The main task of the paper is bringing forward BDOC forecast models by the multi-dimensional linearity regression method, the principal components regression method and neural network (BP). The BP model has higher precision to the BDOC forecast than the other methods.