Project Number: 6226-63000-001-14
Project Type: Reimbursable

Start Date: Oct 01, 2007
End Date: Mar 31, 2010

Objective:
To demonstrate the efficacy, cost-effectiveness, practicality, and sustainability of treating biosolids (sewage sludge) with water treatment residuals (alum sludge).

Approach:
A series of rainfall simulations on small plots will be conducted to demonstrate the effect of liquid and solid water treatment residuals on P and metal runoff from liquid and solid sewage sludge. Biosolids will be applied at a rate of 1 dry ton equivalent/acre. Soluble and total P and soluble metal content of biosolids will be determined. Rates of alum-sludge that will be utilized should reduce P runoff by 50 to 75% (20, 30, and 40% wt/wt basis). The effect of water treatment residuals on phosphorus runoff from biosolids will also be evaluated using three small watersheds. One of the watersheds will be unfertilized, one will receive untreated biosolids and the third will be fertilized with biosolids treated with alum sludge. The soils in these fields will be sampled periodically for water soluble P and Mehlich III extactable P, water soluble metals, pH and electrical conductivity. The fields will be equipped with flumes and automatic water samplers to measure P and metal runoff. Dry matter production and metal uptake by the grasses will also be evaluated. Costs associated with disposal of biosolids and water treatment residuals in landfills will be compared to costs associated with this new BMP. Savings (revenue) generated by this practice should be sufficient to significantly improve point source discharges, assuming the new revenues would be utilized at the WWTP for chemical treatment. When the project is near completion, several tech transfer meetings will be held in NW Arkansas to educate wastewater treatment plant personnel on the best way to utilize this technology.