Great East Japan Earthquake Strikes Sewerage System
Takeshi Yamauchi
3. Impact on People Life
3.1 Different timing of other infrastructures recovery such as water treatment
Right after the earthquake, water supply was cut off because waterworks were damaged and power plants were shut down. Therefore, there were no problems relating to sewerage system. However, unlike sewerage systems, waterworks do not locate near coastal area. They locate at mountain area in the mountain regions, so the damages were relatively small, and the recovery was very much faster than sewerage systems. Some regions got their waterworks repaired in a week, and waste water started to flow down to sewerage systems, even though their sewerage systems were still out of service. In Tagajo city on March 16th, overflow of waste water from manhole was reported and leak badly. (16) It is said that the full recovery of sewerage system will take few years, but the more the recovery of other infrastructures proceed, more the chance of people exposed directly to raw or poorly treated waste water.
3.2 Temporary housing cannot be build due to damaged sewerage system
It is said that we will have to build 72,000 temporary houses for those who lost their houses in this Great East Japan Earthquake. The government expressed a desire to construct 30,000 temporary houses within two months. Municipals arranged land for construction, and construction companies ordered materials for housing. However, the construction of temporary housing is not going on smoothly. One of the reasons was that it was difficult to construct sewerage system due to land subsidence. Therefore, septic tank was planned to be constructed (17).
3.3 In some regions, people were using river water as domestic water
People living near the coastal area, like Minamisannriku in Miyagi, still cannot use their water supply thus; people go to the river to wash their clothes. However in some basin where purification plant is out of service, waste water is discharged from pump station located at the upstream area with an emergency treatment. Such plants need to research the condition of downstream area before discharging the waste water. (18)
3.4 Sanitation problem in evacuation areas
One of the biggest problems caused by the damage of sewerage system in this earthquake was sanitation problem in evacuation areas. Japanese Red Cross Ishinomaki Hospital carried out a research in March 31 and found out that about 40% of evacuation areas toilets didn't work well in Ishinomaki, Higashimatsushima, and Onagawatyou in Miyagi. In the research, about 50 people had been reported with diarrhea and 20 people reported with nausea, and infectious disease were spreading in refugees. There were areas that did not even have temporary toilet. People in those evacuation areas were making up a wall using cardboard and relieve themselves using newspapers and then buried in the ground or collected at one place. Because the condition of toilet was very bad, people tried not to use toilet many times causing their health to deteriorate.
Sanitation in evacuation areas affects people's physical health and mental health, so we need to take measures. For one measure, introducing "manhole toilet" is being considered. Manhole toilet can be built right above the manhole. We can send human waste directly into the sewerage systems by opening up the manhole and setting up this manhole toilet. (19)