Pilot tests of microbe-soil combined treatment of waste drilling sludge

Microbe-soil combined treatment is a newly developed technology in view of the defects of the curing process and waste drilling mud slag properties. In particular, 0.3%–0.5% bioremediation reagents were fully mixed with the waste drilling sludge according to its wet and dry degree, and 1.5 folds to twice weight of more finely ground soil was added in the mix, which was covered by soil of 5–15 cm thick and thereby grasses or greeneries were planted on the soil. The process was successfully applied to some fields of Well Danqian 001-8, Well Lianhua 000-X8, etc. After three months of such treatment, the main indexes of the drilling solid waste such as the degradation of COD and the oil-degrading ratio reached more than 90%, the index of leaching solution met the requirement of the first grade in the national “Integrated Wastewater Discharge Standard”; heavy metal ion concentration in soil did not change significantly with the indicators meeting the requirement of the third grade in the national “Soil Environmental Quality Standard” (Dry Land); and no harmful effects of heavy metals have ever been found on the planted grasses and greeneries. In conclusion, with this microbe-soil technology, the soil property will recover its background values without any other chemical additives, realizing the ecological restoration and reuse of land covered by wellsite wastes, so it is in line with the energy-saving and environmentally-friendly treatment way.