Research Trends and Results

A guide to the discharge and treatment of wastewater
during a disaster
HARADA Ichiro, HeadYAMASHITA Hiromasa, Senior researcher
HAMADA Tomoyuki, Researcher
Wastewater and Sludge Management Division, Water Quality Control Department（Key words）
Wastewater discharge, Treatment function, Emergency measures, Staged emergency
restoration works
1. Introduction
The Great East Japan Earthquake of March 11,2011 damaged sewerage treatment plants at 120
locations, and the tsunami inflicted disastrous
damage so severe it caused the failure of all
functions at many sewerage treatment plants andpumping stations along the coastlines of thestricken prefectures. Basic concepts for emergency
measures and staged emergency restoration
concerning sewerage system functions which must
be ensured during a disaster have been presented in
the Report by the Sewerage Treatment System
Earthquake / Tsunami Countermeasure Technology
Study Committee established in response to theGreat East Japan Earthquake (hereafter“Committee report), and local governments where
the earthquake caused damage have been carryingout staged emergency restoration based on thisreport.
On the other hand, more large earthquakes arepredicted, so there is a growing need to prepare fordisasters that will cause the loss of sewerage
discharge and treatment functions.
2. Investigation on damaged local governments
MLIT and NILIM are taking advantage ofknowledge gained responding to the Great East
Japan Earthquake by surveying the impacts ontreatment functions of sewerage treatment plants
and on the waters receiving discharged treatedwastewater, at the emergency restoration stage andare studying methods of appropriately managing
sewerage during disasters, in order to clarify
concrete measures to ensure sewerage system
functions during disasters. And they have also
surveyed and analyzed cases of emergency
measures and emergency restoration of seweragesystems operated by local governments in thedisaster region.

3. Publication of “A Guide to the Discharge andTreatment of Wastewater during a Disaster(Draft)”.
Based on knowledge gained from the results ofthese studies, and considering the results ofinvestigations by the Committee to Study
Appropriate
ManagementofSewerage
Treatment at the Restoration Stage following a
Disaster, we have prepared “A Guide to theDischarge and Treatment of Wastewater during a
Disaster (Draft)” and announced it. This guide is
to show the idea of securing the wastewater
discharge and treatment function required at thetime of disaster by the “Emergency measures”
pursuant to the site situation and improving
those functions through gradual “Stagedemergency restoration works.”“Emergency measures” are to grasp overall
damage status of the facilities immediately after
the disaster and summarize those items which isrestricting the implementation of emergency
measures and then swiftly discharge thewastewater from living space of disaster stricken
people so as to prevent waterborne disease fromprevailing. This Guide explains the key points of
the Committee report such as necessary
investigations, actions and publicity activities
at the time of disaster. In addition, this guide
explains cases of measures under this disaster.
“Staged emergency restoration works” are toselect and implement temporary treatment tokeep sanitary environment in the city andconserve the water quality in receiving water
body in the course of proceeding on the fullrecovery of the treatment function when it isexpected to take time until completing the fullrecovery. Based on the Committee report, wehave summarized countermeasure method andeffect from the case of the “Staged emergency
restoration works” in this disaster in this guide.

Research Trends and Results
In addition, this guide explains the concept on
the design and maintenance of each treatment
method and disinfection method.
We anticipate that this guide will be applied
to prepare sewage works by administrator for
future disasters and to respond to disasters.

Photo Example of emergency restoration
works （Temporary sedimentation tankconstructed by rough digging）