Written by: Emmanuel CAMPBELL
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As of 2020, it is estimated that about 380 billion (B) m3 of wastewater are discharged annually. In Japan, the annual wastewater discharge is 14.7B m3, which represents 3.9% of the total wastewater released globally. Wastewater is used water that contains substances such as human waste, oils, and chemicals. If not properly managed it can cause harm to fish and wildlife populations, depletion of oxygen in water, and contamination of drinking water.
Wastewater organic contents increase the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). A continuous increase in BOD and COD reduces the amount of oxygen available to fish and aquatic life and this will eventually lead to the death of fishes and other aquatic organisms. The presence of suspended solids (SS) in water bodies makes water treatment for human consumption difficult which can eventually lead to scarcity of consumable water among the communities using the local water sources. In Japan, the permissible limit of COD and BOD is 160mg/l, while SS is 200mg/l.
Shin-Etsu (SE) is a Japanese-based manufacturing company that specializes in the production of Polyvinyl Chloride, Electronics, and Functional materials. SE has revenue of USD13.7B and a workforce of 22,783 employees7. In 2019, SE discharged 186Mn m3 of wastewater globally, which contains 28.2mg/l of COD, 3.7mg/l of BOD, and 5.3mg/l of SS.
Out of the 85.2B m3 of water used annually in Japan 88% is obtained from rivers, of which 20% are used for domestic purposes. SE did not report the final destination of the wastewater for all its manufacturing sites, however, a report on two of its plants shows that wastewater was discharged into rivers.
The total wastewater discharged by SE in 2019 accounts for 1.3% of the wastewater produced in Japan per annum.
Wastewater produced by SE is bountiful and harmful to the environment. SE must implement measures to reduce its wastewater by effective water recycling methods.
