Chapter ３　Water Environment Measure

　Nutrient enrichment which is the main cause of water pollution of lakes is occured by abnormal growth of phytoplankton due to influx of nitrogen and phosphorus. As the measure, it needs to control the growth factor of phytoplankton.
　There is the following as phytoplankton growth factor.

　・Water is retain, not circulated.
　・Nitrogen and phosphorus flows from river, it has increased by elution from the bottom mud.
　・Photosynthesis is activated by sunlight.
　・Phytoplankton cells are present.

　One of those, nutrient salts such as nitrogen and phosphorus are discharge from the basin. It is effective to remove before entering lakes and rivers flowing into lakes basin measures or lakes and marshes influx measures.
　Direct removal light blocking and phytoplankton, improvement of water retention are lakes within the measures.

　Measures to reduce nitrogen and phosphorus from the basin lakes and dam.

　・Measures to sources
　By spread of human waste treatment facilities such as sewerage systems, the measure is carried out to reduce nitrogen and phosphorous in daily wastewater. It is also considered about advanced treatment such as denitrification and de-phosphorus etc. are also considered.

　・Drainage regulations
　Measures on the basis of the Water Pollution Control Law, to strengthen the regulation of water discharged from a particular facility.

　・Surface-source measures
　As spill response farmland, from the forest and there is a drainage measures, such as in the underdeveloped areas of sewer management and fertilizer application.

　River inflow purification method is direct purification method which treat nutrient salts such as nitrogen and phosphorous in the river before into lakes, marshes, and dams.
　In the method to remove nitrogen and phosphorous in river inflow to lakes, marshes, and dams, it is necessary to use natural purification which doesn't affect on environment and doesn't use energy a lot.

　●CarbonFiber purification facility
　By CarbonFiber's large surface area absorption and activation of attached microorganisms, organic matters are decomposed. Since the balance of aerobic bacteria and anaerobic bacteria of attached microorganisms is good, denitrifying bacteria works well thus, removing nutrient salts.
　Purification is carried out by direct purification facility in rivers which CarbonFiber is installed in Inflow rivers into lakes, marshes, and dams, or separated direct purification facility which brings river water separately.

　　　→Separated direct purification method by CarbonFiber（CarbonFiber Make Water Method Association）

Lakes and marshes water purification by measures toward inflow rivers

●Plant purification facility
　By high plants which use nytrogen and phosphorous like phytoplanktons, inflow river is purifified. In measure by vegetation, hydrarch plants are suitable since river water continuously comes in. In general hydrarch plants, there are emergent plant such as reeds and wild rices, floating leaf plants such as water caltrops, submerged water plants such as hydrillas, floating plants such as water hyacinths and duckweeds.
　Contamination matter remove mechanim by reed fields is carried out by complex process which includes chemical function such as settling and absorption and biological function related to reed field Eco system. 　

●Measure of nitrogen and phosphorous reduction
　For reduction of nitrogen and phosphorous in lakes, nitrogen decomposition, phosphorous fixation, and sludge decomposition by CarbonFiber water purification material and aquatic plants are effective.
　As the existing methods, absorption by plants' root as nutrients and dredging nutrient salts contained in sludge are carried out. However, in serious contaminated areas, it is not effective since plants only need nutrient salts for their growth. oreover, dredgign construction spends lots of constrcution fee and the cost effectiveness is small. In addition, it leads Eco system destruction.

　（１）Use of CarbonFiber water purification material
　CarbonFiber water purification material is directly installed in lakes, marshes, and dams and purifies as contact media biofilm method. Treating inflow lake water which is called inflow contact aeration biofilm method is effective.
　In case of stagnant water area, it might be lack of DO, the effect will increase by aeration which activate microorganisms. Also, to increase effective treatment by making CarbonFiber touch to lake water, it is better that artificial circulation facility is installed.

　　　→Lakes and marshes direct purification by CarbonFiber（CarbonFiber Make Water Method Association）

　（２） Use of aquatic plants
　・The purification by lake vegetation zone
　・The purification by floating island
　・Wetland

　（３）Bottom sludge measures
　Sedimentary bottom sludge contains nutrients, so measures to remove (dredging) for prevent the dissolution sludge and overlaying sand which is coated with sand should be carried out. It can reduce the leaching of organic matter and nutrients from bottom sludge, but due to dissolution of redeposition from bottom sludge, the effect decrease as well as it is low cost-effective. Therefore it is important to additionally conduct measures to generation control together.
　It is possible to decompose sediment sludge degradation by laying in the bottom textile CarbonFiber water purification material.

　（４）Flow control
　There is a way to partition the water-stopping such as "fraction fence" of lake surface, to control the flow of lake, to inhibit the growth of phytoplankton like blue-green algae. Due to shallow aeration of air diffusion, inflow river water of low temperature and high density compared to lake injects to lower than algae production layer, and then control is turned down the supply of nutrients.

　（５）Use of chemical agent
　It is coagulation settling of phosphorus by spraying chemical agents and flocculent on the lake, but putting chemicals in natural waters, it may lead to impact on Eco system and increase in sediment.

　（６）Use of ecosystem functions
　It is a test for method of reducing the phytoplankton indirectly by release of fish species that eat the phytoplankton directly and reducing fish species that prey those fish species.
　Bivalve filter the large amount of water, they feed on organic matter such as phytoplankton in the water. Purification method using these organisms is an effective way from the aspect of food production.

　（７）Oxygen supply
　It purifies water by supplying oxygen directly in the lake and it increase the dissolved oxygen (DO). As the oxygen supply method, there are air aeration, fine bubble aeration, high concentration of oxygen water supply and ozone generator.
　
　（８）Direct removal of phytoplankton (blue-green algae)
　The way to remove collected directly occurring phytoplankton in lake by using a peculiar ship.

Removing blue-green algae

　●The nutrient enrichment measures by lake circulation release
　The way of artificial circulation, there are air, pump, screw, water mill type etc, also apply of the release and inflow of flow energy.
　Air type has aeration effect, so it is use to DO supplementation and control elution of hydrogen sulfide in the bottom layer.
　With circulating the lake, blue-green algae is dropped sharply and it changes diatoms and green algae. Because odorant seaweeds are disappearance, odorant problem is solve in many cases, also oxygen deficiency of bottom water is solve at the same time, therefore iron, manganese, ammonia and hydrogen sulfide etc. are disappearance.

Water circulation method

Shore circulation method

Shallow aeration method

Double separation aeration method

Deep water aeration method

Intermittent aeration method

Continuous aeration method

（１） Planar lake circulation

・Water circulation method
　In the case of small lakes, shallow water depth, by circulating in a plane in the water, it plan to oxygen supply and water purification.
　By installing the circulation area of CarbonFiber water purification material, shaking of the carbon fiber, polluted water contact with the microbial membrane, adding the purification effect.


・Shore aeration method
　It is circulation by lake water supply to the other side at a point away with the pump equipment, then to plan oxygen supply and water purification.
　By installing the circulation area of CarbonFiber water purification material, adding to purification effect.




（２）Deep lake water aeration

・Shallow aeration system
　System to plan growth inhibition and lowering the algae activity by send to hypolimnion nearby do not receive light algae due to aeration and circulation of the surface water layer.



・Double separation aeration method
　System doing aeration and circulation separately for hypolimnion and surface water layer, and at the same time inhibit the growth by sending to layer out of reach of light algae, to supply the dissolved oxygen in the hypolimnion.



・Deep aeration method
　System to supply the dissolved oxygen by aeration of the hypolimnion, It suppress the elution of phosphorus and H₂S from bottom sediments, to prevent the occurrence of H₂S smell and control the growth of algae.



・Intermittent aeration method (all layers circulation)
　System of inhibiting the growth of algae by transferring the layer does not reach the light in large circulation by wind-driven flow.



・Continuous aeration method（all layers circulation）
　System of inhibiting the growth of algae by transferring the layer does not reach the light in large circulation by wind-driven flow.