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EnviroBlend® vs. Lime

Lime-based treatment technologies (ie. lime/Portland Cement/CKD) are sometimes able to bring metal-contaminated waste to TCLP standards, however there are many shortfalls that must be taken into account when selecting a treatment chemistry.

The benefits of using EnviroBlend versus Lime
  EnviroBlend Lime/Portland Cement/CKD
Chemical Reaction and pH Regulation EnviroBlend chemistries help to stabilize the pH of the environment over time. Since many metals leach at both high and low pHs, pH maintenance is imperative to long-term stability.  Lime-based treatment can often drive pH up too quickly and irregularly. It will often pass the TCLP test, however, may not continue to stabilize waste over time if the pH increases after treatment.
Chemical Cost Due to the superiority in effectiveness of EnviroBlend technologies, a typical dosage rate is 1%-10%.   This enables total chemical expense,  as determined by cost of treatment per ton, to be kept at a minimum.  Up to 75% savings over lime-based treatment is possible. Lime-based treatment typically is effective at dosage rates of 10%-100%, significantly higher than that required of EnviroBlend.  Costs associated with quantity of material needed for treatment can drive up expenses in removal, transportation, and production.
Bulking Factor Lower bulking factor decreases material handling expense, improves production and typically shortens project duration. Higher bulking factor increase amount of material handling, and therefore increases production time.
Transportation and Disposal Costs Total transportation and disposal expense decreases due to lower bulking; there is less material to be transported and disposed Higher bulking factor drives transportation and disposal expense up due to higher volume of material.

The use of lime based technologies are sometimes able to beat the TCLP test (within a narrow dosage window), but it can be seen that they fall significantly short compared with the EnviroBlend chemistry. The table below shows the effectiveness of the EnviroBlend chemistry resulting in the very low leaching in both the TCLP (acid) and SPLP "Acid Rain" tests. Both the lime and Portland cement treatments are able to sometimes beat the TCLP test at high dosages but they actually increase the amount of the lead leaching in the SPLP test.

Treatment of Lead TCLP Hazardous Wastes Actual Test Results on a Sample of Smelter Slag
  TCLP (acid) Leach Test Hazardous Waste Criteria (mg/L) SPLP Acid Rain (Water) Test
  Lead(mg/L) Final pH   Lead(mg/L) Final pH
Untreated 600 6.0 5.0 <0.003 8.2
Lime (Calcium Hydroxide) (% by weight)
+5% 76 6.5 5.0 290 12.2
+10% 0.2 8.6 5.0 540 12.5
+15% <0.2 10.4 5.0 11 11.9
Portland Cement (% by weight)
+5% 450 5.3 5.0 19 11.5
+15% <0.2 10.4 5.0 11 11.9
+25% 1.2 11.6 5.0 12 11.9
+50% 10.0 12.0 5.0 3.0 12.1
EnviroBlend® Chemistry (% by weight)
+4% 2.4 5.8 5.0 <0.003 10.6
+6% 0.4 5.5 5.0 <0.003 10.3
+8% <0.2 5.6 5.0 <0.003 8.5
Note: All samples crushed to pass a 9.5 mm sieve per Method 1311 Toxicity Characteristic Leaching Procedure,
40 CFR, Part 261, Appendix II.