| Defects such as high operating cost, complex management and large quantity of surplus sludge are common in the traditional wastewater treatment process, which results in the facts that quite a lot of domestic wastewater treatment plants cannot run properly or are even left idle, thus seriously preventing the development of wastewater pollution control. At present, few wastewater treatment establishments have been built for most small towns in our country, as a result, sewage is discharged directly without being treated and such untreated sewage has become the main pollution source. With the rapid development of town construction and the ever-increasing requirement of environmental protection, it is imperative under the situation to develop and popularize actively low-cost and high-efficiency techniques for wastewater treatment, so as to conserve our limited freshwater resource and improve the quality of our water environment, which is meaningful for pushing forward wastewater treatment in small towns. This dissertation mainly deals with the organic removal features of HABR(Hybrid Anaerobic Baffled Reactor), hydrophyte purification function and the operating features of multivariate biological ecosystem composed of HABR, contact oxidization and plant zone of purification. The research results are as follows: ⑴ The biomass in the reactor can accumulate markedly when carrier layer is added to the HABR reactor, thus strengthening its purification function. In pilot experiments, the removal efficiency of CODCr can reach 70%~80% when the organic loading rate is controlled in the range of 1~2 kgCOD/(m3·d) and the HRT is set at 5.3~7.9 hours. ⑵ The research results of the purification function of the aquatic plants cultivated in the static water reveal that Cana generalis, Cyperus alternifolius and Calla palustris can get rid of NH3-N, TN and TP. Cana generalis has the most powerful removal ability, Calla palustris comes next and Cyperus alternifolius ranks the third. When HRT=8d, the removal efficiency of NH3-N, TN and TP are 78.0%, 70.8% and 96.3% respectively. ⑶ The removal effect of CODCr and SS in a demonstration HABR project is apparent and the average removal efficiencys are 61.4% and 57.5% respectively. Move than 60% of NH3-N is oxidized by nitrobacter in the contact-oxidization tank; the average removal efficiency of TN and TP by constructed wetland are 56.9% and 60.5%. It means that the whole treating system depends on the mutual action of the multivariate biology to get rid of various pollutants. The concentration of NH3-N,TN and TP in the outflow can reach the Class One criterion of Discharge Standard of pollutants for Municipal Wastewater Treatment Plant. ⑷ The demonstration project verifies that the multivariate biological wastewater eco-purification system with the anaerobic microbes as the core and aerobic microbes and purification of plant as the subsequent processes has the advantages such as sound treatment result, low investment and low operating cost, less surplus sludge, simple management requirements. It turns out to be an advanced practical technique that is suitable to be popularized in the domestic small towns. |
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