About past process of City of Yokohama, Environmental Planning Bureau sewage sludge destruction by fire ash and future correspondence (plan)
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The handling of sewage sludge destruction by fire ash containing radioactive material  


Reason why radioactive material came to be included in in 1 sewage sludge destruction by fire ash

 Diffuse radioactive material reaches the Yokohama-shi sky by atmospheric flow with Tokyo Electric Power The Fukushima Daiichi nuclear disaster and flows into sewage pipe by rain and reaches the water reproduction center. We handle in water reproduction center and sludge exploitation of resources center, and sewage finally becomes sewage sludge destruction by fire ash. Because radioactive material flowed into sewage pipe like the said article, radioactive material came to be included in sewage sludge destruction by fire ash. As for such phenomenon, the local government of neighborhood is in a similar situation, too.


About landfill disposal of 2 sewage sludge destruction by fire ash

Land of Minamihonmoku landfill carries out landfill to part targeting at destruction by fire ash after April, 2014.

About inning disposal of sewage destruction by fire ash (Portable Document Format 354KB)

≪Past process of sewage sludge destruction by fire ash≫

(1) We announce landfill to Honmoku, Nichinan landfill on September 9, 2011  
  ・Confirmation safe about landfill of sewage sludge destruction by fire ash → We announce landfill after September 15

(2) We freeze landfill to Honmoku, Nichinan landfill on September 14, 2011  
  ・Till because explanation was inadequate for people concerned, give enough explanations; landfill "freeze"

(3) The explanation situation to citizen, the person concerned 
  ・Using document which explained contents of "safe evaluation examination book about landfill of sewage sludge destruction by fire ash to management type disposal ground" clearly, we explained to citizen, the person concerned.

(4) We suggested and explained future correspondence plan of sewage sludge destruction by fire ash to citizen, people concerned in September, 2013.  
 About past process of sewage sludge destruction by fire ash and future correspondence (plan) (Portable Document Format 1.03MB)
  
  Oh, we utilize when we make occurring destruction by fire ash land of disposal ground every day and, as the first stage, examine landfill

  About destruction by fire ash which has already kept i in sewer facility, we examine the future handling 

  We promote utilization as resources in cormorant lower water sludge sequentially
   (we follow clearance level (100 becquerels/kg or less) surely, and exploitation of resources as use of improved soil plans exploitation of resources sequentially.)

(5) We start exploitation of resources as construction material in addition to exploitation of resources as conventional improved Hijiwara charges in July, 2014.

(6) We carry out examination landfill in Minamihonmoku refuse landfill of mixed ash which mixed garbage main ash and sewage sludge destruction by fire ash of Resources and Waste Recycling Bureau for from February to March in 2015.

(7) We start landfill by method like examination landfill in July, 2015.

Change of the storage situation and the radiological density of 3 destruction by fire ash

The storage situation of current sewage sludge destruction by fire ash is as follows.
 The storage situation of past sewage sludge destruction by fire ash is this. (Portable Document Format 156KB)

 The storage situation of sewage sludge destruction by fire ash approached to approximately 38,000 tons in south, northern part sludge exploitation of resources center at peak hour, but disposal advances and gradually decreases. However, it is in a situation that we cannot but still put in hall road and parking space and influences facility administration.
 
On the other hand, the radiological density of sewage sludge destruction by fire ash decreases to approximately a one-50th in comparison with the beginning of storage start.

The radiological density of 4 sewage sludge

 It is result of a measurement of radioactive material levels of inflow sewage, discharge water, dewatering sludge, sludge destruction by fire ash, improvement soil in Motoichi sewer facility and inning disposal mixture ash in Minamihonmoku refuse landfill.
(1) Inflow sewage, discharge water
  ・About inflow sewage and discharge water, it was the non-detection.
Past radioactive material concentration data are this. (Portable Document Format 34KB)

(2) Dewatering sludge, sludge destruction by fire ash, improved soil  
                                          Unit (becquerel /kg)    

Name Northern sludge exploitation of resources center Southern sludge exploitation of resources center
Dewatering sludge Sludge destruction by fire ash Improved soil Dewatering sludge Sludge destruction by fire ash
Sampling day 2017
September 25
2017
October 10
2017
October 12
2017
October 2
2017
October 10
Cesium 134 The non-detection 16 The non-detection The non-detection 15.6
Cesium-137 8.99 139 The non-detection 11.0 125

※We show that it is less than fixed-quantity lower limit level with the non-detection.
  Fixed-quantity lower limit level of the non-detection is cesium 134: 10 becquerels/kg, cesium-137: 10 becquerels/kg
※About iodine 131, we began the measurement for index to confirm influence of nuclear plant accident, but, based on half-value period of iodine 131 having already passed more than three years for 8th, we remove from measurement item from September 1, 2014 and itemize 2 of cesium 134 and cesium-137.  
・Past radioactive material concentration data are this. (Portable Document Format 79KB) (excel form 146KB) (... end of August, 2014)
・Past radioactive material concentration data are this. (Portable Document Format 53KB) (excel form 47KB) (September, 2014 ...)

 In addition, sludge destruction by fire ash keeps in the northern part and site of southern sludge exploitation of resources center.

(3) Inning disposal mixture ash
 We carried out examination landfill in Minamihonmoku refuse landfill of mixed ash which mixed garbage main ash and sludge destruction by fire ash of Resources and Waste Recycling Bureau for from February, 2015 to March. We confirm safety by examination landfill and carry out landfill from July, 2015 without abnormality being recognized to air dose and radiological density afterwards as we were able to confirm security.
                           Unit (becquerel /kg)

Date September 15, 2017
Mixed ash cesium concentration 83.5

・Past radioactive material concentration data are this (Portable Document Format 32KB); (excel form 30KB) 
・As we fill up in September, 2017 and finished disposal, about inning disposal mixture ash, there will not be update in future.


Space emission dose rate of 5 site borders  

                                         Unit (in microsievert /)                               
Name The east side The westThe south sideThe north sideMeasurement day
Northern sludge exploitation of resources center (Suehirocho, Tsurumi-ku) 0.05 0.05 0.04 0.05 2017
September 22
Southern sludge exploitation of resources center (Sachiura, Kanazawa-ku) 0.05 0.05 0.06 0.05 2017
September 22
 ※We measure at point of 1 meter in height from ground


・Past space emission dose rate data are this. (Portable Document Format 36KB) (excel form 37KB)


Radioactive material concentration in 6 effluent gas

 It was the non-detection about effluent gas.                
Past radioactive material concentration data are this. (Portable Document Format 39KB)


7 documents

Safe evaluation examination book (Portable Document Format 474KB) about disposal such as sludge destruction by fire ash containing radioactive material

・Explanation document about the handling such as sludge destruction by fire ash containing radioactive material
 (Portable Document Format 6,693KB for color) (Portable Document Format 9,014KB for black and white)
※As for "the radioactive exposure around the figure 3-4 body of these 20 pages of explanation documents," data of origin of quotation are updated. Please refer to the following URLs for the details.
 http://jccu.coop/food-safety/qa/pdf/qa03_03_02.pdf

Common question is this. 

City of Yokohama, Environmental Planning Bureau sewer Facilities Department sewer facility management section - June 15, 2011 Making - October 17, 2017 Update
It is inquiry - ks-shisetsukanri@city.yokohama.jp - telephone opinion: 045-671-3969 - FAX: 045-641-4870
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