ABSTRACT

Spent drilling mud (DM), a co-product during horizontal directional drilling operations, needs proper disposal to comply with social and environmental sustainability awareness, with one option being its cost-effective reuse as a soil amendment. The possibility was investigated of DM applications to improve the physical quality of loamy sand soil. The soil was treated with increasing DM contents in a laboratory at volumetric DM-to-soil ratios of 0:100 (DM0, no DM), 25:75 (DM25), 50:50 (DM50), 75:25 (DM75), and 100:0 (DM100, no soil). The mixtures were analyzed for water retention, available water capacity, water storage capacity, S-index, soil aggregate stability (SAS), and chemical quality based on pH, effective electrical conductivity (ECe), sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP). The optimal ratio of DM and the control (DM0) in the batch experiment were selected for application to three species of forest plant seedlings in the field. The results showed that DM positively influenced soil physical qualities. The water retention increased (from 10 to 67%) with increasing DM, but the most suitable ratio was DM25, considering its water storage capacity deviated the least (1.4%) from the optimal value. DM25 also produced the highest S-index (0.081). The SAR data increased with the drilling mud application rate (1.1 to 10.9). However, the DM25 pH remained at 7.7, with an ECe of 2.5 dS m⁻¹, a SAR of 7.0, and an ESP of 9.2, which were still favorable regarding soil structure, as indicated by no decrease in SAS with added drilling mud. In the field experiment, DM25 also decreased the water deficit of the three species of forest plant seedlings, suggesting a positive attribution to other relevant soil-plant systems. DM could be a feasible option to improve soil physical quality, but further long-term experiments are necessary before applying it as a soil amendment in real situations.

Implications: With the demand in energy-driven economics, establishing national energy security nationwide in Thailand requires the installation capacity, transmission, and distribution pipelines. Horizontal directional drilling (HDD) operations are generally used to install underground pipelines, generating large amounts of drilling mud rich in sodium bentonite as a co-product. At present, drilling mud is becoming a more serious solid waste and has been raised in proper management. The best management practices are expected to reuse as a soil amendment, a cost-effective approach, for coarse-textured soils. Before any drilling mud application can be introduced to agriculture and the environment, we must clarify the optimal rate of drilling mud. This rate has to significantly improve soil physical quality associated with air-water capacity balance while minimizing the adverse effect of residual sodium to favor soil structure and sensitive plants.

摘要

废钻井泥浆 (DM) 是水平定向钻井作业期间的副产品，需要适当处置以符合社会和环境可持续性意识，其中一种选择是将其作为土壤改良剂进行经济有效的再利用。研究了应用 DM 以改善壤质砂土物理质量的可能性。在实验室中以 0:100 (DM0, 无 DM)、25:75 (DM25)、50:50 (DM50)、75:25 (DM75) 的体积 DM 与土壤比例对土壤进行处理，增加 DM 含量, 和 100:0（DM100，无土壤）。根据 pH 值、有效电导率 (ECe)、钠吸附比 (SAR) 和可交换性，对混合物的保水、有效水容量、储水能力、S 指数、土壤团聚体稳定性 (SAS) 和化学质量进行了分析。钠百分比 (ESP)。选择分批试验中DM与对照(DM0)的最佳比例应用于大田3种森林植物幼苗。结果表明，DM 对土壤物理质量有积极影响。随着 DM 的增加，保水量增加（从 10% 到 67%），但最合适的比例是 DM25，考虑到其储水量与最佳值的偏差最小（1.4%）。DM25 也产生了最高的 S 指数 (0.081)。SAR 数据随着钻井泥浆应用率（1.1 到 10.9）而增加。然而，DM25 pH 值保持在 7.7，ECe 为 2.5 dS m 随着 DM 的增加，保水量增加（从 10% 到 67%），但最合适的比例是 DM25，考虑到其储水量与最佳值的偏差最小（1.4%）。DM25 也产生了最高的 S 指数 (0.081)。SAR 数据随着钻井泥浆应用率（1.1 到 10.9）而增加。然而，DM25 pH 值保持在 7.7，ECe 为 2.5 dS m 随着 DM 的增加，保水量增加（从 10% 到 67%），但最合适的比例是 DM25，考虑到其储水量与最佳值的偏差最小（1.4%）。DM25 也产生了最高的 S 指数 (0.081)。SAR 数据随着钻井泥浆应用率（1.1 到 10.9）而增加。然而，DM25 pH 值保持在 7.7，ECe 为 2.5 dS m^-1、7.0 的 SAR 和 9.2 的 ESP，这对土壤结构仍然有利，如添加钻井泥浆后 SAS 没有降低所示。在田间试验中，DM25 还减少了三种森林植物幼苗的水分亏缺，表明对其他相关土壤-植物系统的积极归因。DM 可能是改善土壤物理质量的可行选择，但在实际情况下将其用作土壤改良剂之前，还需要进一步的长期实验。

影响：随着能源驱动经济的需求，在泰国全国范围内建立国家能源安全需要安装能力、传输和分配管道。水平定向钻井 (HDD) 操作通常用于安装地下管道，产生大量富含钠膨润土的钻井泥浆作为副产品。目前，钻井泥浆已成为较为严重的固体废物，并已得到妥善管理。最佳管理实践有望作为土壤改良剂重新使用，这是一种具有成本效益的方法，适用于质地粗糙的土壤。在将任何钻井泥浆应用引入农业和环境之前，我们必须明确钻井泥浆的最佳用量。