The water purification evaluation of the gravel contact oxidation method

• Main Authors: Chih-Jung Lee, 李志榮
• Other Authors: Jiang-Jhy Chang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/15684130580130307674

碩士 === 國立臺灣海洋大學 === 河海工程學系 === 95 === Abstract This research aims to analyze one Gravel Contact Oxidation Engineering by Nanhu Bridge located at one benchland outside the left embankment of the lower section of Keelung River. Such engineering is built to process the “dry weather flow” gathering by “Nanhu Storm Water Pumping Station” sending into Keelung River, of which the capacity of the on-site wastewater treatment equipment is 8,000 cubic meters, and the average processed quantity each day is 5,500 cubic meters. In order to realize the actual effect of the pollution-removal of such engineering, this research is designed to take example out of the water at the inflow and outlet channel thereof, for the reason that the inflow and outflow only flow in the single way, and further that there is no recirculation equipment built in the system thereof. Therefore the variation of the density between the inflow and outflow channel can be used to analyze the effect of the pollution-removal made by such system. For the further research of the state and the process of the decomposition of the various pollutive materials occurring inside of the system, and for the analysis of the example taken constantly in the full process, the sampling position is set to be seriate inlet, sampling pipe 1 (aeration zone of the former section of the sampling well), sampling pipe 2 (aeration zone of the later section of the sampling well), sampling pipe 3 (non-aeration zone of the sampling well) and the outflow trough. The purpose of the arrangement is to analyze the mechanism of the removal of variety of pollutive materials. The major items of the water-analysis are B.O.D (Biochemical Oxygen Demand), S.S. (Suspended Solids), NH3 -N (Ammonia Nitrogen) and D.O. (Dissolved Oxygen). Based on the outcome of the analysis, the removal-rate of each item is as following: B.O.D., between 49%~96.5% (averagely 84.5%), S.S., over 85%, NH3-N, over 96% (averagely 98.8%), and the concentration of D.O. stands between 4.1 to 8.9 mg/L, which is approximately 3 mg/L higher than inflow. Meanwhile, the adjustment to the aeration has significantly affected the nitrification efficiency of NH3-N. If we analyze all those pollutive materials item by item, we have found that the removal-rate of NH3-N under double-aerator operation stands at 99.8%, however such rate under single-aerator operation decreases to the level of 89.6%, which indicates aeration is the important factor to the removal of NH3-N. This research has set the fully-nitrification as the goal of the design of the equipment construction and allocation, as well as the operating process. And such goal has been confirmed through the water examination during the trial of the system. Given by the facts that the removal of NH3-N and the aeration are directly relevant, if it’s by the need of power-saving or because of the unnecessary of the fully-nitrification, it can be taken into consideration to test the decrease of 50% or of all of the aeration for long period, so that the influence of each item of the quality of water under different operating condition can be fully understood. Keywords: on-site wastewater treatment, Gravel Contact Oxidation,nitrification