Land Application of Urban Horizontal Directional Drilling Residuals to Established Grass and Bare Soils

Joshua Daniel,Hailin Zhang,João Antonangelo,Chad Penn

doi:10.3390/su122410264

Abstract

Horizontal directional drilling (HDD) is a non-invasive alternative to trenching used for the installation of many common utilities. The process involves drilling fluid used to stabilize the borehole, lubricate the bit, and float cuttings to the surface. A sustainable alternative to landfill disposal is land application. Two field studies were conducted to determine the optimum application rate of HDD residuals to both established bermudagrass and bare soil seeded with bermudagrass. Residuals were applied at six rates ranging from 0 to 112 tons solid ha−1 for both trials. Soils were sampled 7, 30, and 90 days after application. Saturated paste and Mehlich-3 extractions were performed on all samples. Grass biomass was measured at the end of the study. No significant amount of nutrients or trace metals were found in the treated soils. All concentrations were in the range of typical soils. However, total dissolved solids (TDS) and sodium absorption ratio (SAR) increased with application rate. There was no significant difference in the yields of forage harvested on the established grass plots 110 days after application. Bare plots that received 22 tons solid ha−1 had higher percent ground cover than other rates. It is ecologically safe to apply HDD residuals up to 112 tons and 90 tons solid ha−1 to established bermudagrass and bare soil, respectively.

Highlights

In the last three decades, there have been many scientific studies generating a great deal of information on the benefits and environmental impacts associated with the land application of many types of residuals [1]
The field study included the establishment and monitoring of two field trials upon which Horizontal directional drilling (HDD) residuals were applied to both established grass and bare soils at six different application rates
Soil tests for K indicated 100 to 92% sufficient for bermudagrass with concentrations of 96 to186 mg kg−1 at the two depths

Summary

Introduction

In the last three decades, there have been many scientific studies generating a great deal of information on the benefits and environmental impacts associated with the land application of many types of residuals [1]. Adverse environmental impacts on both soil and plant growth after the land application of oil and gas drilling fluid may occur due to the high concentrations of soluble salts, which are found primarily in water-based mud. Biosolids are another by-product commonly land-applied since they contain both organic and inorganic plant-available nutrients as well as soil conditioning properties, giving incentives for its use as a source of fertilizer [5,6,7]. The application of fly ash to agricultural land cannot supply crops with the macronutrients nitrogen (N) or phosphorus (P) and it can contain different amounts of trace metals such as arsenic (As), copper (Cu), nickel (Ni), lead (Pb), chromium (Cr), and zinc (Zn), which does put a limit on its potential use as a soil amendment [11,12]

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