Ammonia recovery from wastewater by membrane distillation coupling sulfuric acid absorption and ice water condensation

• Main Authors: Bo-hao, Ji, 紀柏豪
• Other Authors: 黃文鑑
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/v99k58

碩士 === 弘光科技大學 === 環境工程研究所 === 104 === In recent years, it will executed more stringent ammonia（NH3） limits than now day on effluent wastewater in the semiconductor industry, from A.D. 2012 to A.D. 2014, effluent ammonia limits 75 mg/L is down to 30 mg/L；NH3 is harmful very major on the environment, it is caused to eutrophication, reduced the amount of dissolved oxygen in the water, even it increased in greater cost of processing expenses when the amount of chlorine must is increased in the water, in the current, it removal of ammonia is bad in wastewater treatment processes, it will impact the semiconductor and other industries seriously, and therefore it must be found to an effective way to treatment ammonia in the wastewater, and it is reduced the impact and harm on the environment. It main to recover the ammonia in this study, the experimental design is strip NH3 by the membrane distillation in the wastewater and it is absorb NH3 by sulfuric acid, the control parameters is including temperature, pH value and concentration of sulfuric acid. The another experiment is dissolved NH3 gas in ice water by ice water and venturi tube, it obtain high concentrations of NH3 water. The experimental results show that it is absorb NH3 of the optimum concentration of sulfuric acid is 18 N in the sulfuric acid, the temperature is 50 ℃ and pH = 11, it is obtained the recoveries of 65 %；In addition, it condensed to recovered ammonia by ice water, the temperature is lncreased higher in the range of 50 ~ 70 ℃ when the concentration of ammonia is recovered higher, and the optimum conditions of the temperature is 70 ℃；In pH = 11 to 12 range, the recovery rate is increased not evident with changing in the pH value in the test, in the test is analyzed to recovery rate of ammonia is reached significant results at pH = 11 or more. it is recovered NH3 of 70 %, 66.59 % in the synthetic wastewater and wet etching washing wastewater, they are recovered ammonia so great, and the current the max concentration of ammonia is reached to 4300 mg/L by ice water.