The Effect of Active Calcium Treatments on the pH Levels and Amount of Sludge in Acid Mine Drainage Amanda Grant Deep Run High School Henrico County Public Schools

Purpose Determine which active calcium treatment would raise the pH of acid mine drainage closest to neutral while creating the least amount of sludge.

What is acid mine drainage (AMD)? Origin: abandoned coal or metal mines Pyrites + water+ oxygen= AMD Potentially flows into waterways where it disrupts the environment T. and L. ferrooxidans speed up the rate of generation of AMD

Acid Mine Drainage…. Can be visually detected by the yellow- orange color which comes from iron- containing flocculates and precipitates.

Problems with AMD Pyrites entering waterways Increased acidity levels: Creation of flocculates: Sterile waterways Damage habitats Decline in human outdoor activity Destroys food webs Threatens biodiversity Corrosion of man-made objects

How to treat AMD… raise pH above 7 Types of Alkaline Chemicals: *limestone *hydrated lime *pebble quicklime caustic soda soda ash ammonia Drawbacks : sludge created Types of Treatments: *ActivePassive Allow naturally occurring processes to decrease acidity in a controlled area

Methods and Materials Collected water from Contrary Creek in Louisa County, Virginia

Methods and Materials… Four beakers were filled with 50 ml of creek water  Group A: control: no treatment  Group B: 0.5 g of limestone  Group C: 0.28 g of pebble quicklime  Group D: 0.37 g of hydrated lime pH meter was used to measure each pH every half hour until neutralized.

Results: Descriptive Statistics AMD Chemical Treatments A: Creek Water (control) B: LimestoneC: Pebble Quicklime D: Hydrated Lime Mean Range Minimum Maximum Variance Standard Deviation Number of Trials10 Inferential Statistics A vs B t= 29 B vs C t= 27.9 C vs D t= 0 A vs C t= 67.8 B vs D t= 27.9 a = 0.05 A vs D t= 67.8 Df= 18 table t= The Effect of Different Types of AMD Treatments on pH Levels

The Effect of Different Types of AMD Treatment on the Amount of Sludge Descriptive Statistics AMD Chemical Treatments A:Creek Water (control) B: LimestoneC: Pebble Quicklime D: Hydrated Lime Mean Range0333 Minimum0111 Maximum0444 Variance Standard Deviation Number of Trials10 Inferential Statistics A vs B t= 8.5 B vs C t= 1.2 C vs D t= 0 A vs C t= 8.2 B vs D t= 1.2 a = 0.05 A vs D t= 11.3 Df= 18 table t= 2.101

Conclusions: Reasons for Findings Limestone increased the pH closest to 7, while creating least amount of sludge  Carbonate solutions such as limestone do not increase the pH of water above 8.5.  Hydroxides such as hydrated lime can raise pHs above 10. Some metals require pH levels around 10.5 to precipitate so limestone may not have been the most efficient.

Future Studies: Test all six active treatments Active Treatments versus Passive Calcium versus sodium compounds

Improvements: Larger quantities of water tested Flowing water rather than stagnant More specific measurements: centiliters Test rate of neutralization, pH levels, amount of sludge, and the amount of metals remaining in water after treatment.

The Effect of Active Calcium Treatments on the pH Levels and Amount of Sludge in Acid Mine Drainage Amanda Grant Deep Run High School Henrico County Public Schools