Effects Of Growing Aquatic Plant Species On Purification Of The Discharged Water From Brewery Wastewater Treatment Plant

Eutrophcation has become severe environmental problem in the world recently.Brewery wastewater contained a considerable organic matter. If onproperly treated,the direct release of brewery wastewater to the surrounding environment could leadto severe eutrophication. However, even after biological treated, which remove mostof the organic matter, the wastewater still contains large amount of nitrogen andphosphorus. The direct drainage of discharged water has become one of theimportant factors which lead to the water pollution. Taking the discharged waterfrom brewery wastewater treatment plant in Hangzhou as an example, this studytook the aquatic plants as research object and studied the function of aquatic plantsin water treatment. The scientific basis is provided for phytoremediation. And themain results obtained were summarized as follows:1. The removal rate for ammonia nitrogen was over 94.50％by Vetiveriazizanioides, Canna generalis, Thaliadealbata, Pontederia cordata L. and lrispseudacorus L. in the discharged water. Among them, the removal rates ofammonia nitrogen by Canna generalis and Thaliadealbata were the highest,reaching 98.92％and 98.20％, respectively. The removal rates of total phosphoruswere over 72％by growing aquatic plants. Vetiveria zizanioides and Iris pseudacorusL. had an outstanding ability in removing total phosphorus; and the removal rateswere 87.74％and 84.27％, respectively. The removal rates of COD were over 87％by growing aquatic plants; and Thaliadealbata has an great ability in removing CODfrom the discharged water (the removal rate was 93.41％). Canna generalis andPontederia cordata L. had a higher ability to remove BOD.2. Both Canna generalis and Thaliadealbata have showed a better purificationability in differential acid water. The values of ammonia nitrogen, total nitrogen andtotal phosphorus decreased in different degree with treatment time of 20 days. Theremoval rate of ammonia nitrogen increased positively with the pH of dischargedwater. At pH 9, the removal rates of ammonia nitrogen by Canna generalis and Thaliadealbata were the highest, reaching 99.97% and 99.98%, respectively. Therewas no significant differences between the two plant speies (P＞0.05). At pH6-7, theremoval rates of total nitrogen by Canna generalis and Thaliadealbata were thehighest, and .reached 99.30% and 99.53%. Similarly, the highest removal rates ofphosphorus (99.09% and 98.58%, respectively.) were obtained at pH6-7 by growingthe two plant species for 20 days. The removal of total nitrogen and total phosphoruswas considerably inhibited when the pH was too higher or too low, while theremoval of tatal phosphorus was more affected by higher pH.3. There were significant differences between the maximum rates of ammonium,nitrate and phosphorus uptake by Canna generalis and Thaliadealbata and the Kmvalue of absorption. The maximum rates of ammonium, nitrate and phosphorusuptake by Canna generalis were 0.0394, 0.0189 and 0.0067 mmol/gFW hr,respectively. And the Km values of absorption of it were 1.2517, 1.0537 and 0.1225mmol/L, respectively. The maximum rates of ammonium, nitrate and phosphorusuptake by Thaliadealbata were 0.0301, 0.0362 and 0.0151 mmol/gFW hr,respectively. And the Km values of absorption of it were 0.7608, 0.8634 and 0.1405mmol/L, respectively. The results showed that Canna generalis could be used forpurification of higher ammonium when compared with Thaliadealbata, while couldbe used for the water with wider concentration of nitrate because of its highermaximum rates of nitrate and lower value of Km. And Thaliadealbata was moreadaptable for purifying the wastewater with lower concentration of phosphorus.4. In order to obtain efficiency removal of nitrogen and phosphorus, the suitableplants should be selected according to the pH and nutrition of different types ofwastewater. It is better to combine different kinds of plants for nutrition removal inpractical application. Canna generalis has been used for purifying water for a longtime; and the results showed that Thaliadealbata could also purify the wastewatereffectively. Canna generalis and Thaliadealbata were flowers, and thuswereexcellent of both ecological and landscape.