Ozonation-biological Activated Carbon Process Crustaceans And Inactivation Of Biological Control Research

The inactivate effection of shellfish vertebrates by chlorine is studied due to the security and filter clogging caused by the bio-leaking, aiming at the breeding of shellfish vertebrates in BAC filter. A new kind of inactivate agent is developed and the effection is studied. Changing backflushing mode of filter, chlorination baceflushing and adding sand cushion are also in pilot plant test and productive experiment scale.The effect of controling shellfish vertebrates by optimization and improvement of process is evaluated.The cultivating method in lab of shellfish vertebrates is build, providing necessary conditions of developing inactivate agent. By long-term cultivation and tracking observation, the main food of shellfish vertebrates is: biofilm on activated carbon, protozoa and carcase. The biofilm quantity of different depth of carbon and the density of shellfish vertebrates is investigated, and a obvious relationship between the biofilm quantity on activated carbon and the density of shellfish vertebrates is obtained.Contrast experimen found that adding quantity should be not less than 1.0mg/L using chlorine as a oxygenate to inactivate daphniathe, and the inactivate period can be within 40min when the concentration is more than 3.0 mg/L.The agent concentration should between 1395mg/L to 1656mg/L to inactivate cyclopoida and harpacticoida in 5min when multitype agent is used, and 70% removal is achieved in 1 min. Calanoida and bosmina is inactivated totally in 5sec when using 825mg/L multitype agent. Calanoida is very sensitive to this kind of multitype agent. Upto 50% of calanoida is inactivated in 5sec even the concentration is 115mg/L. Experiment revealed that the effect of air blast and the combination of air and water blast is much much better than water alone. The effect of twice backflushing is better than once in shutter filter. In the peakperiod of shellfish vertebrates breeding, adding the period of combination of air and water blast and twice backflushing should be taken to inhence the controling of shellfish vertebrates. The removal of vertebrates, cyclopoida and shellfish nauplius is 42-54% by rinsing backflushing, which is lower than the 56~70% removal of water containing chlorine. The intercepting effect of living things by sand cushion is notable, and the population and quantity are reduced by 42.9%and 39.0% respectively. The average turbidity and particle counts when there is and not sand cushion are 0.124NTUand 0.096NTU,281and 242 respectively. Then the influence of sand cushion to turbidity and particle counts is not so obvious.