Chapter ３ Water Environment Measure
Basic measure
Water contamination factors are perfectly or particialy treated in the discharged places.
・Daily wastewater
There are human waste and living wastewater, it is discharged through processing a variety of systems, including sewer.
・Discharge of pollutants from factory and industry system
It is discharged after treatment depending on the water quality.
・Agriculture and farm
It is discharged as agricultural waste with rain water.
・Non-point such as forests and urban
Exhaust gas such as nitrogen oxides discharge through rainfall and groundwater as surface source.
→bout water contamination, let's review in "２. Water Crisis §３.Water contamination"
These flows into the river, some flows into stagnant water area such as lakes, dam and weir etc., in the end, flows to the sea. In stagnant water area such as lakes and dam, by flowed nitrogen and phosphorus, abnormal occurrence of phytoplankton occurs, and eutrophication, that may cause water pollution. As these measures, there are the following classifications.
●Measures of basin
Basin load reduction measures
●Measures of water area
Direct purification measures for river
・Inflow rivers measures
・Rivers in measures
Lakes measures
・Lakes flow into rivers measures
・Lakes in direct purification measures
Organic matter treatment
●Organic matter removal
Treatment of organic wastewater is divided into the following.
・Physical treatment
・Chemical treatment
・Biological treatment
Physical and chemical treatment are advanced treatmemts which are usually used as pre and post biological treatment. Main treatment is a biological treatment.
In biological treatment, there are aerobic and anaerobic treatment. Both treatment have been conducted with the mechanism of natural purification action. In biological wastewater treatment technology, the part of function is artificially facilitated, and microorganisms which are suitable in each environment decompose orgasnic matters.
●Biological treatment
Aerobic treatment
Under aerobic conditions, organic matter is oxidized by contact action and they are decomposed to carbon dioxide and water. Aerobic treatment are high speed reaction, and it has no odorous stench as well as it is compact. Thus it can be installed in a residential area, but it need to supply of air into the tank.
��Activated sludge method
This method is most popular due to high efficiency.
・Conventional activated sludge method
・Anaerobic - aerobic activated sludge method
・Oxidation ditch method etc.
��Biofilm method
Biofilm method is rich biota in diversity compared to activated sludge, and it is likely to proceed such as corresponding to the load change, degradation of refractory organic matter and nitrification reaction. In addition, maintenance is easy, and it used predominantly for smaller institutions in small sewer and septic tank.
・Contact aeration method
・Rotation plate contact method
・Trickling filter method
・Biofilm filtration method etc.
Water purification with CarbonFiber is also one of the biofilm method, and it uses CarbonFiber as filter media contact.
Anaerobic treatment
Under anaerobic conditions, decomposition proceeds in reduction, and organic matter is decomposed to methane and carbon dioxide. Anaerobic treatment which doesn't need air is energy-saving manner because it enables to use the generated methane gas. However there is also a disadvantage. Device size is large, and it requires long residence time because of the reaction rate is slow and odorous emission.
Anaerobic - aerobic cycle
Because it can stay in the near neutral pH by the nitrification denitrification, this is an effective approach to carrying on efficient processing. With the anaerobic aerobic cycling method, organic removal capability also greatly enhanced.
●Physical chemical treatment
This treatment is used when advanced treatment is demanded or biological treatment can't decompose and remove.
・Filtration
・Chemicals aggregation
・Film separation
・Activated carbon adsorption
・Ozone oxidation
・Biological activated carbon etc
●The organic matter treatment with CarbonFiber
Organic matter decomposition with CarbonFiber is conducted by microbial film formed on CarbonFiber. On carbonFiber water purification material, anaerobic and aerobic bacteria adsorb in good balanced, so organic removal capacity will increase by CarbonFiber contacting with organic matter in water. Compared with conventional filter media, due to excellent characteristics such as large surface area and high bioaffinity, microorganisms fix in large and minimal peeling off, therefore water purification effect is continue for the high qualities.
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Organic decomposition
under aerobic and anaerobic condition |
Organic decomposition
by microbio film |
Nutrient salts (nitrogen and phosphorus) treatment
●The nitrogen removal by biological treatment
It is spread into the atmosphere as N2 nitrogen gas by two processes, nitrification reaction (oxidation) and denitrification (deoxidization).
●The phosphorus removal by biological treatment
Phosphorus captured by microorganisms are immobilized accumulation occurs as polyphosphoric acid.
●Physical and chemical nitrogen and phosphorus removal
There are flocculation method, crystallization, adsorption phosphorus removal and iron electrolysis method, in large-scale facilities such as sewage treatment plant, flocculation method most widely used in the past.
●The nutrient salts removal by CarbonFiber
In the microorganisms attached to CarbonFiber, since denitrifying bacteria are abundant, it is decomposed into nitrate nitrogen and nitrogen gas, and diffuse into the atmosphere. Microorganisms storage phosphate ions as polyphosphoric acid, removed for phosphorus. Further, carbon fibers also help to elute iron ions, it is immobilized and insoluble becomes iron phosphate by the presence of iron ions.
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| Biological N remove |
Biological・Chemical P remove |
Measures of residential wastewater
As a measures of residential wastewater, there are complicated treatment tank, single treatment tank, human waste dipping up tank and house treatment. Water contamination measures are mainly for sewage improvement, complicated treatment water tank are used in areas where the sewer treatment does not proceed.
●Sewer measures
Sewerage system dissemination rate in Japan is about 69.3% (March 31, 2006), and sewer project implementation rate by prefecture is about 82% (the number of sewer project municipalities / total number of municipalities). With improving of sewer, water pollution in the rivers of Japan has improved.
However, in recent years, a large amount of rain water flows to the sewer during heavy rain in the combined sewer system. As the results, it is a problem as the cause of the pollution flows from the outlet.
●Treatment tank measures
In the single treatment tank, since untreated domestic wastewater is discharged, pollution load increases. Therefore, it required to facilitate installation of complicated treatment tank which treats domestic wastewater at same time.
●Residential non-fecal wastewater
Other than change to complicated treatment tank, there are measures to use exclusive non-fecal wastewater treatment system or measure at home. Discharge control measure at kitchen places where produce the most amount of waste, such as proper disposal of used cooking oil and phosphate-free detergent for washing.
Measures of industrial wastewater
For factory wastewater measures, suppression of wastewater by the reuse of factory wastewater and by drainage regulations with the Water Pollution Control Act are conducted. Also, pollution removal by wastewater treatment in accordance with the pollution characteristics have been made.
Factories and business places with specific facilities over a certain size are subject to stringent regulations under the Water Pollution Control Law in Japan. About 75% of industrial water came to be covered by re-use, and it has been significantly reduced the amount of usage water and drainage.
・Industry for generating a wastewater with organic pollutants
→ Biological treatment method
・Industry for generating a wastewater with mainly of pollutants of inorganic
→ Coagulating sedimentation method and、 sand filtration system etc.
In addition, as a contact media for biological treatment method, CarbonFiber water purification material are expexted to have large effects, and it has been expected to develop expand applications by the research and development.
Measures of farmland and livestock wastewater
・Livestock system wastewater measures
The amount of load discharged by cattle and pig are 5-10 times more than the discharge load by man, so in a prosperous area of livestock industry, those excreta treatment and wastewater treatment measures are important.
In Japan, from the viewpoint of effective utilization of organic resources, the livestock manure are used as fertilizer in farmland and green space. However, if the amount is huge, it might be flown out with rainfall as non point source load.
Currently, in the purification process for the livestok wastewater contained urine, biological treatment of aerobic, activated sludge method has been commonly used.
・Non point source load measures
Non point source load in agricultural farm is pollutants that have accumulated such as cropland, pasture, paddock outflow when it rains or the underground seepage outflow. From those fertilized as chemical fertilizer or compost, it becomes a problem flows out mainly eutrophication of substances nitrogen and phosphorus.
●Measures for load from the natural range and pasture
・Improvement of the method of fertilization and harvesting
・Flow prevention from degraded land, etc.
●Measrues for non point source load from agricultural land
・Measures of guidance for excess fertilization and spraying
・Flow prevention of fertilizer by water management in paddy
・Composting livestock manure indoors etc.
Citation：「CarbonFiber Water Use Guideline −Environmental Water Edition −」
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