This paper examined the reduction of residual chlorine in apartment buildings for gravity tank systems.

1. It was clarified that the decrease in the residual chlorine concentration in the water tank has a great influence on the water temperature, water depth,initial residual chlorine concentration,and elapsed time.

2. It was clarified that factors affecting the reduction of residual chlorine in the pipe were the pipe diameter, water temperature,elapsed time and initial residual chlorine concentration.

　塩素消毒された水道水に殺菌作用があることはすでに知られているが, 水道水による含嗽の殺菌作用は明らかにされていない. そこで, 水道水および各種処理後の水道水の殺菌作用を観察し, それぞれの

One method of testing tap water for residual chlorine uses a diethyl-p-phenylenediamine (DPD) reagent. The test is very simple, consisting of adding DPD to the water to be tested and measuring residual chlorine from changes in the absorption of light (coloration). A false positive reaction, however, is known to proceed under the influence of ultraviolet light, making the coloration more intense. Care must therefore be taken with regard to sunlight when the method is used outdoors. In the present study, parameter design was used to develop a chlorine test reagent with high light tolerance. The test system as considered as a measuring instrument with residual chlorine concentration as input, variation pressure distance of optical absorption as output, and the presence or absence of irradiation by ultraviolet light as an error factor. An effective test wavelength was also found through selection analysis.

世界各地で水不足と水質汚染の問題が深刻となっており，衛生的な水の確保は重要な課題である．水の消毒では，遊離塩素と結合塩素の濃度を適切に管理することが重要である．遊離塩素と結合塩素の間には光分解反応速度に差が生じるため，この性質を利用することで遊離塩素と結合塩素の分別が可能であると考えた．本研究では，光照射流路と光照射のない流路への分岐を備えたフローインジェクション分析（FIA）システムを構築し，それぞれの流路を経由して得られるシグナルを時間差で検出した．その結果，それぞれのシグナルの大きさと遊離塩素及び結合塩素濃度の関係から作成した線型方程式を用いることで，一度の試料注入での同時定量が可能となった．次亜塩素酸イオンとクロラミンTの混合溶液を用いて同時定量を試みたところ，仕込み量と同等の値を得ることができた．

本研究では、貯水槽系統の飲用水中の遊離

　塩素注入量は，現在，高度な技術を持つ職員が経験に基づいて注入量を決定しているが，大量のベテラン職員の退職と職員数の減少などから，経験に依存しない，新しい塩素注入量管理手法が求められている．本研究では，浄水場が保有する

　モデル構築にあたって最適なブロックは24時間であり，誤差目標値±0.025以下に収めるには，予測時間を6時間以下にする必要があることが判明した．また，モデル構築に必要最小限のデータ量は4月～7月の4か月間の

Recently in Japan, with the increase of sewage treatment facilities, the treated water discharged to public waters has been also increased. Residual chlorine contained in the treated water has been found to be chronically toxic to aquatic organisms. This paper is intended to clarify the cause of reduction and the behavior of the residual chlorine in river channels. In order to observe a continuous change in the flux of there residual chlorine, we conducted the field survey with water samplings and measurements in the channel with discharged the treated water. According to these results, it has been examined that the residual chlorine in river water has been strongly related to the treated influent water and has been significantly reduced in the daytime due to its solar radiation, and these reduction processes could have been described as the conventional kinetic modellings.

80℃の温水環境におけるSUS445の配管としての使用可能範囲を明らかにするために，実使用環境模擬条件で耐食性評価を行った結果，樹脂製の継手と組わせた場合，