A Study of the Tightness of Rubber Flapper Valve Regarding the Effect of Retention Time of Grey Water in Toilet Water Tank

• Main Authors: Shiu-Chin Shiu, 許旭欽
• Other Authors: An-Ping Liu
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/58089761733178936455

碩士 === 國立高雄大學 === 都市發展與建築研究所 === 98 === Recently on the basis of sustainable management of water resources on campus, a lot of schools whether in Taiwan or not adopt an idea of reusing greywater to flush the toilet. Due to students are absent during winter or summer vacations, most dormitories and classrooms are left unused. Under such a circumstance, the greywater inside a toilet tank will become a stagnant water and let microorganisms attach on the interior or parts of water tanks, and finally form biofilms with an ugly appearance. This study emphasized the water quality variations of greywater during the retention time in toilet tanks, and the impact of biofilms on the tightners of rubber flapper valve of a toilet tank. The present greywater of National University of Kaohsiung was used as the experimental water. On this study the greywater was placed in the water tanks for two months, in order to simulate case of summer vacation. The experimental results are summarized as follows: 1. After greywater staying on toilet water tanks for two months, the noticeable dirty spots and biofilms appeared on the rubber flapper valves and the interior of water tanks. These organic contaminants also actually influenced the tight effectiveness of rubber flapper valves within the water tanks. 2. During the two months of greywater retention time, the amount of total organic carbon (TOC) was increased very fast, the quantity of pH and the electrical conductivity were increased slowly, but the salinity of greywater kept constant. Since the water temperature was lower than that of the original greywater during this experiment, such a situation caused the increase of the percent saturation of dissolved oxygen in greywater, but the dissolved oxygen level of water still kept decreasing with the proliferation of biofilms instead. The experimental data provided by this study will help understand the influence of greywater on the rubber flapper valves of toilet tanks when greywater is for use in flushing toilets. This paper also offered some suggestions to the mainstenance man of campus buildings, regarding the use of greywater recycling and irrigation systems.