Fly ash treatment

About fly ash

Fly ash is ash collected by dust-collecting equipments such as a bug filter set at the exhaust gas exit when burning waste materials by an incinerator or other facilities.

It is generally said that the amount of generated fly ash is about 3% of the total amount of waste. Fly ash is characterized by its high content rate of low-boiling heavy metals such as lead, zinc, and cadmium, or dioxin components.

Therefore, in case that the amount of fly ash containing heavy metals surpasses the criterion (Second standard for amount of dissolution), the Wastes Disposal and Public Cleansing Act (Waste Management Law) requires not to dispose of the fly ash by landfill directly at the controlled-type landfill site. Instead, the fly ash should be treated by an intermediate treatment (in order to prevent heavy metals from dissolution), which is either melt-solidification, cement solidification, chemical treatment, or extraction procedure with acid or other compounds.

"ND Earth Care" enables you to treat fly ash safely at low cost by insolubilizing contained heavy metals with even a small amount.


Environmental Quality Standards for Soil Contamination(Second standard for amount of dissolution)
Second-class specified toxic substance Environmental Quality Standards for Soil Contamination

Second standard for amount of dissolution (mg/L)*3

Standard for contained amount in soil (mg/kg)*1

Standard for amount of dissolution in soil (mg/L)*2

Cadmium and its compounds below 150mg/L below 0.01mg/L below 0.3mg/L
Hexavalent chrome compounds below 250mg/L below 0.05mg/L below 1.5mg/L
Cyanogen compounds below 50mg/L
(As a free cyanide)
undetectable level below 1.0mg/L
Mercury and its compounds below 15mg/L below 0.0005mg/L below 0.005mg/L
 Alkyl mercury undetectable level undetectable level
Selenium and its compounds below 150mg/L below 0.01mg/L below 0.3mg/L
Lead and its compounds below 150mg/L below 0.01mg/L below 0.3mg/L
Arsenic and its compounds below 150mg/L below 0.01mg/L below 0.3mg/L
Fluorine and its compounds below 4,000mg/L below 0.8mg/L below 24mg/L
Boron and its compounds below 4,000mg/L below 1mg/L below 30mg/L

Remarks
*1Standard for contained amount in soil: The standard specifies the lower limit under which health risk is caused by ingesting contaminated soil containing specified toxic substances directly.
*2Standard for amount of dissolution in soil: The standard specifies the lower limit under which health risk is caused by ingesting contaminated groundwater or others due to dissolution of specified toxic substances from contaminated soil containing specified toxic substances.
*3Second standard for amount of dissolution: The standard specifies the selection criteria for measures against contaminated soil.

 

Cases of fly ash treatment with "ND Earth Care"


"ND Earth Care" enables you to treat fly ash safely at low cost by insolubilizing contained heavy metals with even a small amount.

Case: Mixture treatment with the actual equipment used at the Cleaning Center in Taku City, Saga Prefecture
Results of heavy metal stabilization process with ND Earth Care
Name of specimen Amount of heavy metal dissolution(mg/L)
Lead Lead
Before treatment 0.74 2.7
After treatment(1%) ND  
After treatment(2%)   ND
Quantification limit (0.03) (0.03)
Dissolution test on the disposal standard for industry waste (Environmental Agency Notification No. 13 made in 1973)
ND : Less than the quantification limit
Saga Environmental Science Inspection Association


 

Results of heavy metal stabilization process with "ND Earth Care"


Targeted waste material: Fly ash (General waste)
Name of specimen Amount of heavy metal dissolution(mg/L)
Lead Hexavalent chrome Arsenic Mercury Selenium Fluorine
Before treatment 0.003 1.3 0.001 0.0005 0.015 0.9
After treatment 0.001 ND ND ND 0.003 0.4
Quantification limit (0.001) (0.005) (0.001) (0.0005) (0.001) (0.1)
Dissolution test on the environmental quality standards for soil contamination (Environmental Agency Notification No. 46 made in 1991)
ND : Less than the quantification limit
Saga Environmental Science Inspection Association



Targeted waste material: Fly ash (Industrial waste)
Name of specimen Amount of heavy metal dissolution(mg/L)
Lead Arsenic
Before treatment 120 0.002
After treatment(2%) 0.018 ND
Quantification limit (0.001) (0.001)
Dissolution test on the environmental quality standards for soil contamination (Environmental Agency Notification No. 46 made in 1991)
ND : Less than the quantification limit
Saga Environmental Science Inspection Association