Decentralized Treatment for Domestic Wastewater using the Johkasou System Pierre Flamand Manager – International affairs Japan Sanitation Consortium Shinhi Kumokawa Japan Education Center of Environmental Sanitation
Contents 1. History of sanitation improvement in Japan 2. Johkasou technology 3. Legal system and measures for decentralized treatment 4. Examination/training system for johkasou technicians 5. Japan’s experience on decentralized domestic wastewater treatment
1. History of sanitation improvement in Japan
1. History of sanitation improvement in Japan • In the beginning of the 1900s, to prevent the outbreak of waterborne diseases, wastewater from toilets could not be discharged to the environment by law, unless it was treated by a designated method with the assurance that the treated water was free of hygienic problems. The situation remains unchanged after that time. • In the 1920s, a “Filth treatment tank,” which is a septic tank combined with a trickling filter, was developed to treat wastewater from toilets. It was originally using Japanese characters and is the forerunner of today’s Johkasou. • In 1950, the Structural Standards for Sewage Treatment Tanks (Johkasou) were stipulated. Septic tank, Imhoff tank and some aeration processes were introduced in the standards. Johkasou made of RC gradually spread from then. As the number of installed johkasou was small, the maintenance of johkasou was usually conducted at that time by technicians from johkasou manufactures. However, the desludging of johkasou was carried out by the workers of local vendors who, for generations, did the job of removing human waste from vault toilets. 4
1. History of sanitation improvement in Japan ～ 2 nd World War(~1945) Social Background Night soil is valuable and used as fertilizer in rural areas Treatment/disposal of night soil Farmers buy night soil from residents by rice and vegetables. Gray water was discharged into gullies nearby. 5
1. History of sanitation improvement in Japan 1945 ～ 1955 Social Background ・ Decrease of use of night soil in agriculture due to the spread of cheap chemical fertilizer Social needs for hygienic treatment of night soil Japanese Vault toilet Treatment/disposal of night soil Start to constructing night soil treatment facilities nationwide. Anaerobic digestion process was popular. A night soil treatment facility built in the1950s
1. History of sanitation improvement in Japan • In the early 1960s, with the improvement of living standards along with the high economic growth, strong demands for flush toilets emerged. • At that time, vault toilets were popular in houses, which necessitated to remove the night soil storied in tanks every 3-4 months by vacuum trucks and to transport it to night soil treatment facilities for sanitary treatment. • When flush toilets were introduced, vault toilets could not be used anymore as it would be full of wastewater in a short period of time and the night soil collection/transportation system could not deal with it due to limited capacity. • A treatment plant designed for the treatment of individual household wastewater from flush toilets and the discharge of the treated effluent to the environment was proposed . • The improvement of the produced technology enabled the mass-production of household johkasou (Packaged Aerated Wastewater Treatment Plants-PAWTPs). This resulted in the explosive spread of johkasou. FRP-made johkasou in the 1960s 7
1. History of sanitation improvement in Japan 1960 ～ Social Background ・ Huge demands for flush toilets Treatment technology ・ R&D of household wastewater treatment facility (tandoku-shori johkasou ) ・ Gray water discharged into public water bodies Japanese flush toilet Tandoku-shori johkasou for treatment of wastewater from flush toilets （ Effluent BOD 90 mg/L ） 8
1. History of sanitation improvement in Japan 1955 ～ 1965 Social Background ・ High economic development phase ・ Industrialization and urbanization Treatment technology ・ Medium/larger scale johkasou was developed and was put into market 1985 ～ 1995 Social Background ・ Increasing awareness of environment conservation Treatment technology ・ Household johkasou with high treatment performance was developed and was put into market. （ effluent BOD < 20 mg/L ） 9
2. Johkasou technology
Johka-sou Johka = purification sou = tank (in Japanese) 11
リレーションシップ ID rId3 のイメージ パーツがファイルにありませんでした。 Water Pollution by Untreated Domestic Wastewater Adverse environmental High public health impacts risks (pathogenic microorganisms) Pollutant loads (BOD) of domestic wastewater Water pollution by untreated grey water Daily amount of domestic wastewater 12
Pollutant Loads for Johkasou Design Pollutant Loads for one PE (Person Equivalent) 13
Determination of Johkasou Size in Buildings Classified by Purpose of Use (examples) J IS A 3302 J IS A 3302 2000 14
Structures and Treatment Performances of Johkasou 15
Johkasou classified by treatment capacity Small-scale johkasou: 5 to 50 PE, or the average amount of wastewater less than 10 m 3 /day. Medium-scale johkasou: 51 to 500 PE, or the average amount of wastewater less than 100 m 3 /day. Large-scale johkasou: 501 PE or more, or the average amount of wastewater more than 100 m 3 /day. For Residential For Commercial For Community/village 16
Treatment Principles of Johkasou 17
An Example of Small-scale Johkasou (FRP) Influent Sedimentation Chamber Anaerobic Filtration Chamber Recirculation Water (Air-lift Pump) Aerobic Filtration Chamber Storage Chamber Overflow Disinfection Chamber Effluen t 18
A Johkasou for BOD & N&P Removal Device for phosphorous removal リン除去装置 ＜ 槽 外 設 置 ＞ Controler 【防水コンセント】 【制御ボックス】 【電源ケーブル】 【中継ボックス】 Cell base ＜ 槽 内 設 置 ＞ Relay box Connecters 防水コネクタ base 【セル】 Cell Cell base セルベース Bolts 固定 ボルト Electrodes 鉄電極 Effluent water quality BOD <=10 mg/L T-N <=10 mg/L T-P <= 1 mg/L 19
A Small-scale Membrane Johkasou Effluent water quality BOD <= 5 mg/l T-N <=10 mg/l This membrane johkasou could be applied to areas where reuse of treated water is a matter of high priority because of water shortage. 20
Innovation of Johkasou Technology Downsizing of johkasou by Introduction of new biological treatment processes contact aeration ① Moving bed biofilm process; ② Biofilm filtration process; and process ③ Moving bed biofilm-filtration process, instead of traditional contact aeration process Product of the year 2000: L 2,790mm; W 1,140mm; H 1,750mm 64% DOWN in space ① ② ③ 21
Innovation of Johkasou Technology Reduction of energy consumption by ① Development of energy-saving blowers ； ② Introduction of intermittent aeration operation 120 Type1 (60 L/min) for 5PE Energy consumption of blower Type2 (80 L/min) for 7PE 100 80 60 (W) 40 Energy consumption of a new ● type johkasou of 5PE, which is 20 operated in intermittent aeration mode, is only 0.6 kWh/day. 0 1984 1990 2006 2015 22
3. Legal system and measures for decentralized treatment 23
3. Legal System for Decentralized Treatment – Johkasou Act History of Johkasou Act 1960 to around 1980 With increasing population of flush toilet, rapid installation of tandoku During high economic (old type) johkasou to treat black water only growth period, water pollution accelerated. 1983 Johkasou Act enacted (legislation introduced by a Diet member, came into force in 1985) 1987 National subsidy program for gappei (current type) johkasou (to treat both black and gray water) established To promote the spread of 2000 Revised: New installation of tandoku-shori johkasou systems basically gappei johkasou and the prohibited replacement of tandoku 2005 Revised: Stricter water quality management systems introduced, johkasou systems defining water quality conservation targets Purpose of Johkasou Act Promotion of human waste and gray water treatment by Johkasou for; - Conservation of water quality in public water area, preservation of the living environment and improvement of public health ⇒ Articles in Johkasou Act ① Johkasou installation （ ※ related to “Building Standard Law” ） ② Operation/maintenance of Johkasou ③ Approval of Johkasou models ④ Johkasou business for Installation and Operation/Maintenance ⑤ Nationally qualified “Johkasou technicians” ⑥ Miscellaneous and penalties 24
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