Abstract:

In recent years, "farm household tourism" has become a business that has been developing rapidly and concomitantly causing significant increase in wastewater discharge, thus polluting the surrounding environment more and more in extent and posing an urgent problem that calls for solution in rural environment protection in some regions. As the farmer households sponsoring "farm household tourism" are scattered spatially, and vary sharply in wastewater production, it is hard to address this problem effectively with the conventional methods available. The authors have designed and tested a series of "composite-medium bio-filter(CMB)" systems, different in composition of medium, in laboratory for a continuous period of 114 days to investigate technical feasibility and effects of the CNB systems treating this kind of wastewater. Results show that when the wastewater was 2 000-4 500, 15-60 and 6-12 mg·L^-1, in concentration of COD, TN and TP, respectively, on average the CMB systems could remove COD by over 90%, TN by over 80% and TP by over 70%. Mass balance analysis indicates that their NH₄⁺ removal depended mainly on nitrification/denitrification, which was enhanced by the filling of zeolite adsorbing NH₄⁺, while TP removal did on adsorption by the media. The addition of bamboo granules into the medium of the filter could not only stabilize the removal rate of COD and enhance that of TP, but also reduce cost. The test indicates that the CMB, easy to manage and free from any need of energy, is a promising technique for treating the wastewater from farm household tourism.

Key words: compound media bio-filter system, farm household tourism, removal efficiency