| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce volume of an excess sludge produced from a cleaning waste water effectively by passing a liquid to be treated through a biological filtering device in order to remove impurities, peeling off impurities adhering on a filter layer and a biological membrane formed excessively and subjecting them to a high voltage pulse discharge treatment before a biological treatment. SOLUTION: A liquid to be treated, which is introduced into a biological filtering device 1, is aerated through an aeration device 6 and is made to flow through a filter layer 2 in an ascending stream for carrying out biological filtration. If pressure drop increases due to increase in amount of sludge with progress of the treatment, introduction of the liquid to be treated is stopped and air cleaning is carried out in order to peel off the excess sludge adhering on the filter layer 2. The sludge peeled off is washed by a liquid in an upper liquid layer 8 and washing waste water is introduced into a high voltage pulse discharge treatment tank 111 from a washing waste liquid path 9. A high voltage pulse discharge is performed by a high voltage pulse discharge device 34 to change sludge in the washing waste liquid into an easily biodegradable one, and then a high voltage pulse discharge treatment liquid is introduced into a treatment liquid storage tank 13 and biological filtering is restarted in the biological filtering device 1.</p> |
