Wastewater Sludge

Project 1

Combined Land Application of Sludge and Secondary Treated Municipal Wastewater

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Abstract :

Combining the application of municipal wastewater sludge with secondary treated municipal wastewater to land for crop production is a viable way to recycle valuable nutrients. When combined, these two nutrient sources have the potential to provide excess nutrients if careful budgeting of those nutrients does not occur. Nitrogen is viewed as the most important effluent constituent to monitor, but in the arid southwest, maintaining a proper salt balance may be just as important. Metals accumulation in the soil and the potential uptake by plants are two other important factors when considering the land application of sludge. Research was conducted over a 1-year period that included three experiments. The first experiment included the application of raw, filtered sludge at four levels plus a control to plots growing a Sorghum bicolor (sorghum) and Triticum aestivum (wheat) rotation. The second experiment nearby with the same crops included the application of lime-stabilized sludge at three levels plus a control. The third experiment consisted of applying two levels of the raw sludge plus a control to plots growing Medicago sativa (alfalfa). Each test was replicated three times and randomly distributed within the plot matrix with buffer strips to eliminate external variables from influencing the results.