Water Quality Purification Research Articles

Evaluation of ability for water quality purification at the shoal and tidal flat zone in Hakata Bay

Water and sediment qualities were surveyed from April, 1996 through March, 1997 in Hakata Bay for the water-quality modeling. Using the results, the seasonal variations of water qualities were discussed and the ability for water-quality purification at the tidal flat zone was estimated. The amount of organic matter removed by benthos at Wajiro tidal flat was about 2 times larger than that at the reference area. The amount of COD removed by benthos at Wajiro was the same order of magnitude as Banzu tidal flat.

Sedimentation Rate in Enclosures with Various Densities of <i>Eichhomia crassipes</i> in Wulihu, Taihu Lake, China

The dynamic model of physical-biological engineering for purifying water quality in Lake Taihu needs the parameter of sedimentation rate (SR). Especially, it is seldom reported how SR is influenced by interactions between algae and aquatic plant. So 6 enclosures with each area of 5×5 m² were constructed in Wulihu with 2 m depth, a small hypereutrophic bay of Taihu Lake, China. Enclosures, in which the original water quality was the same as that in surrounding lake, were input Eichhomia crassipes at various original densities from 0-6 kg·m^-2 on August 9, 1996. SR had been measured separately at depths of 0.6, 1.2f 1.8 m in each enclosure during 20 days. Main results were as follows:1) SR average in enclosures (17.3g·m^-2 d^-1) was as much as about 1/14 that in the surrounding lake; 2) The deeper was it, the higher rate was it in each enclosure, generally; 3) SR cures versus original densities of Eichhomia crassipes (ODE) in enclosures had the ship of V at different depths; SR minimuma were observed in the enclosure with original meso-density of Eichhomia crassipes (EMESO, 4kg·m^-2), the average of SR minimuma was about 8.55 g ·m^-2 d^-1) SR in enclosures with original hypo-density (EHYPO, 0-3kg·m^-2) were mainly negative related with water temperature and light intensity;while those with original hyperdensity (EHYPR, 5-6kg·m^-2) were mainly negative related with transparency (SD) instead.These SR-distribution characteristics may be explained by interactions between dead algae and relics of Eichhomia crassipes.;The dynamic model of physical-biological engineering for purifying water quality in Lake Taihu needs the parameter of sedimentation rate (SR). Especially, it is seldom reported how SR is influenced by interactions between algae and aquatic plant. So 6 enclosures with each area of 5×5 m² were constructed in Wulihu with 2 m depth, a small hypereutrophic bay of Taihu Lake, China. Enclosures, in which the original water quality was the same as that in surrounding lake, were input Eichhomia crassipes at various original densities from 0-6 kg·m^-2 on August 9, 1996. SR had been measured separately at depths of 0.6, 1.2f 1.8 m in each enclosure during 20 days. Main results were as follows:1) SR average in enclosures (17.3g·m^-2 d^-1) was as much as about 1/14 that in the surrounding lake; 2) The deeper was it, the higher rate was it in each enclosure, generally; 3) SR cures versus original densities of Eichhomia crassipes (ODE) in enclosures had the ship of V at different depths; SR minimuma were observed in the enclosure with original meso-density of Eichhomia crassipes (EMESO, 4kg·m^-2), the average of SR minimuma was about 8.55 g ·m^-2 d^-1) SR in enclosures with original hypo-density (EHYPO, 0-3kg·m^-2) were mainly negative related with water temperature and light intensity;while those with original hyperdensity (EHYPR, 5-6kg·m^-2) were mainly negative related with transparency (SD) instead.These SR-distribution characteristics may be explained by interactions between dead algae and relics of Eichhomia crassipes.

Physical-Ecological Engineering for Purifying Water Quality in Algae-Type Eutrophic Lake——Reconstruction of Macrophytes in Wulihu of Taihu Lake, China

Physical-Ecological Engineering for Purifying Water Quality in Algae-Type Eutrophic Lake——Reconstruction of Macrophytes in Wulihu of Taihu Lake, China

A Physico-Ecological Engineering Experiment For Purifying Raw Water Quality in A Lake

我国许多历史上水质优良的湖泊水源区已遭污染或严重污染,净化饮用水源刻不容缓.本文介绍了自1991年以来在太湖进行的物理-生态工程(PEE)的部分研究成果.着重介绍在太湖的重富营养湖湾──五里湖无锡中桥自来水厂水源区的静态和抽水动态实验.阐明了PEE净化水质的原理,示范工程结构,若干水生植物生长规律,螺对水的净化作用及工程效果等.PEE能有效地除藻和净化水质.工程对水的浊度、铵氮、亚硝酸氮和色度的降解效果较好,1994年8月-1995年6月间工程输出水比工程外原水分别平均削减82%,60%,69%和46%.;Water quality was very good in many middle-large scale lakes and urben lakes in China before 1970s. These lakes were selected as the raw water sources for advanced treatment of drinking water and/or recreation lakes. But the eutrophication process developed rapidly and the water quality in more and more lakes is lower than the standard for drinking and recreation recently. Purifying raw water quality in lakes is an urgent problem faced in many regions for sustainable development. Some Physico-Ecological Engineering (PEE) experiments in Taihu Lake have been doing since 1991. The research results were summarized partly in this paper, including the principles for purifying water quality, the construction of the model engineering, the growth laws of some species of floating plants, the roles and effects of snail (Bellarnya aeruginosa) in purifying water quality, and the efficiency of PEE. The experiment took place in the hypertrophic bay of Taihu Lake -Wulihu Lake, in the intake area of Wuxi Zhongqiao Drinking Water Supply Plant (ZDWSP), with an experiment area of 2200m² and depth of about 1.6m. The static and dynamic pumping experiments have been doing since August 1994. The PEE may effectively remove algae and purify water quality. The mean reducing rates of PEE for turbidity, NH₄⁺-N, NO₂⁺-N, and colour are 82%, 69%, 69%, 46% respectively during August 1994-June 1995.

Water Quality Purification in a Bay by Intake or Outlet of Cooling Water

As a method of water quality purification in a bay, it is proposed to use an intake or outlet of cooling water of a power plant. It is shown that the relation of water exchange and water quality, and the calculation results of the change in water quality in the case of taking water from the inside of the bay and draining it into the outside of the bay, and that of taking from the outside and draining it into the inside.

砂浜の機能を有する多孔質コンクリートへの生物付着と水質浄化

砂浜の機能を有する多孔質コンクリートへの生物付着と水質浄化

Influence of Concentration of Nitrogen and Percolation on Water Quality Purification and Growth of Rice

Influence of Concentration of Nitrogen and Percolation on Water Quality Purification and Growth of Rice

接触酸化法による都市下水路の水質浄化実験

接触酸化法による都市下水路の水質浄化実験

Field Test of Water Quality Purification Using Underdrains

Field Test of Water Quality Purification Using Underdrains

The water quality purification system for the enclosed sea area

The water quality purification system for the enclosed sea area

特集 各省庁の水質保全対策の新しい動き 閉鎖性海域を中心として 運輸省における閉鎖性海域の水質保全対策

特集 各省庁の水質保全対策の新しい動き 閉鎖性海域を中心として 運輸省における閉鎖性海域の水質保全対策

Field Test about Characteristics of Air Bubble Plume

Recently air bubble plume has been suggested as a method of water quality purification. In this study, air bubble characteristics, flow induced by air bubble rise and destratification by the flow have been investigated by field test.As the results of the study, following concequences were obtained.1. Bubble diameter is 5-7cm.2. Bubble velocity is 50-150cm/s and can be expressed by way of function of air supply.3. Volume flux ratio can be explained by the equation which is induced in field in which there is not stratification. But there is the maximum value of volume flux ratio.