| 摘要 |
<p>The flow velocity of the water is first reduced, floating impurities are removed from its surface and it is subjected to a biological cleaning process before being allowed to soak into the ground. Removal of floating impurities may take place during or after the velocity redn. stage, and biological cleaning may be combined with this first treatment stage. The water is accumulated to a certain surface level during the treatment before being allowed flow to waste. The system comprises a tapering inlet channel, a sedimentation and accumulation tank, a floating material separator and a biological filter tank from which the water flows to waste. The separator is installed in one of the pipelines leading from the sedimentation tank to the biological filter tank, and the amt. of water flowing to it is controlled by a flow device. The filter tank is filled with a granular material such as gravel, and is at least partially planted with plants. The floor of this tank is at a lower elevation than the floor of the outlet drainage channel, and its upper edge is above the normal water level in this channel. USE/ADVANTAGE - Used where cleaning of accumulated rainwater, melted snow, etc. from surface drains is required before allowing it to be disposed of. The return of the water to seas or lakes or the ground water table without contamination is made possible, and the proposed system is effective and economic and operates independently and without the need for energy input for pumping, etc.</p> |
