Factors causing sandy filter - media darken , darken - controliing technology , and influence of darkened and regenerated sandy media on filtration in surface water plants are studied in this thesis 本文对地表水厂的石英砂滤料黑化成因、控制技术及石英砂黑化滤料和清洗再生滤料对过滤的影响进行了研究。
To solve the problem of sand loss and harden , it is suggested that the diameter of media and the intension of back wash should be enlarged properly , and the time of back wash should be prolonged 但为解决滤料黑化以后在反冲洗中出现跑砂及滤料结块的现象,建议水厂适当加大滤料粒径和反冲洗强度,延长反冲洗时间。
The result was preferable while use tap water , acidic solution with ph = 3 . 0 and alkali solution with ph = 12 . 0 as regenerant . for the convenience of operation , it is suggested to adopt tap water as regenerant 用自来水、 ph = 3 . o的酸液和ph = 12 . o的碱液作为再生剂分别对吸附后的黑化砂进行再生,发现再生效果都比较好。
In addition , adding potassium permanganate before coagulating can remove manganese at efficiency of more than 60 % , which will reduce enrichment of manganese on the sand so that sand darkening can be retarded 在混凝前投加高锰酸钾可以使原水中锰的去除率达60以上，能有效减少锰元素在滤料上的富集，延缓滤料的黑化。
These spores disintegrated or menalized finally . the experiment showed that injection of high dose spores destroyed the immune system of the cockroach and the cockroach was easy to be invaded by bacterial pathogens 注射较高浓度的孢子后，许多参与免疫的血细胞也会黑化，最后裂解，血淋巴中也出现了较多血细胞和组织的碎片。
Ph had obvious influence on the adsorption : the adsorption percentage increased along with the ph value increased in adsorbing mn , while adsorption percentage has the maximum value under the neutral ph condition in adsorbing sb Ph对黑化砂的吸附有明显的影响:吸附锰时,吸附百分数随ph的增大而增大;吸附锑时,吸附百分数在ph = 7时有最大值。
Taking improving the whole world life ' s as it ' s main power . our group would like to be the first class enterprise tn the world to create , produce more products tn the field of modern science in order to meet social requirements 黑化集团将以改进整个世界生活素质为主要动力，旨在成为世界一流的化工企业，在现代科学领域中不断创新和生产新产品以满足社会的更大需求
This daytime darkening is valuable for protection against enemies and sunlight , and for many years it was thought to be a simple response by the crab to the sun - just as if we were to get a tan during the day and lose it at night 这种白昼黑化是针对敌人和阳光的有价值的自我保护，很多年以来，它被认为是蟹对于太阳光的一种简单反应，就像我们人类白天皮肤被太阳晒黑，晚上又会白回来。
This daytime darkening is valuable for protection against enemies and sunlight , and for many years it was thought to be a simple response by the crab to the sun - just as if we were to get a tan during the day and lose it at night 这种自昼黑化是针对敌人和阳光的有价值的自我保护，很多年以来，它被认为是蟹对于太阳光的一种简单反应，就像我们人类白天皮肤被太阳晒黑，晚上又回白回来。
Further , economic analysis showed that using the darkened sand could reduce operation cost . however , it is suggested that strict inspecting of water quality should be applied for the blacked sand , and preliminary filtrating time should be prolonged in order to ensure water quality 这表明黑化砂与清洗再生砂对过滤的出水水质无明显的不良影响，可以在生产中使用，但对黑化砂必须严格监控水质，适当延长初滤水的排放时间，以保证出水水质。
