An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in t...An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed: the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.展开更多
The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new...The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new signs of vegetative and reproductive organs have been checked out and elaborated. It leads to the clarifying of new taxonomic status and geographical distribution of certain critical taxa. A set of species are threatened and need special measures which are included into the Red Data Book of Russian Federation. for their conservation. There are 13 species and one variety展开更多
基金Supported by the National Water Pollution Control and Harnessing Projects (2009ZX07423-003)
文摘An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed: the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.
文摘The largest and most important family in Russian conifers is Pinaceae （27-29 species）. The most important problems in the field of systemitics concern some critical taxa. In the result of author＇s research, the new signs of vegetative and reproductive organs have been checked out and elaborated. It leads to the clarifying of new taxonomic status and geographical distribution of certain critical taxa. A set of species are threatened and need special measures which are included into the Red Data Book of Russian Federation. for their conservation. There are 13 species and one variety
