Currently, there are mainly three methods to address HDD mud problems: sedimentation, dilution, and mechanical removal.
Sedimentation: One or more mud pits are dug at the entry and exit points of the crossing. The returned mud is channeled into the pits. After a certain period of natural settling, the upper liquid phase is extracted for the mud circulation system, and the bottom solid phase is discarded. Advantages: Simple operation, low cost, low energy consumption; Disadvantages: Large footprint required, slow settling/separation speed, and the bottom solid phase is difficult to clear out.
Dilution: The mud returned from the crossing is collected in mud tanks, and then water, bentonite, and additives are added to adjust the mud properties required for the crossing, aiming to reduce the solid content of the mud. Advantages: Simple method, low cost; Disadvantages: Incomplete solid phase removal.
Mechanical Removal: This method uses a solids control system to separate the solid phase. A solids control system refers to a setup composed of shale shakers, desanders, desilters, desander cleaners, desilter cleaners, horizontal decanter centrifuges, and circulating large tanks, configured according to specific solids control requirements. In most cases, mechanical removal is the most effective and economical method.
As can be seen, the most effective and feasible means of treating mud currently is mechanical removal. For example, the Horizontal Directional Drilling (HDD) Mud Recycling System produced by Xi’an KOSUN Machinery is an effective mechanical removal solution for solving mud pollution.
The KOSUN Machinery Horizontal Directional Drilling (HDD) Mud Recycling System uses a multi-stage purification process of “shale shaker + desander + desilter” to efficiently separate solid particles from the mud, achieving over 90% mud recycling and reuse. Specifically, the shale shaker can remove solid particles >1.5mm, the desander can remove solid particles from 0.074mm to 1.5mm, and the desilter can remove solid particles from 0.02mm to 0.074mm. After treatment, the suspended solids in the separated wastewater are ≤50mg/L, allowing it to be directly reused in construction or discharged in compliance with standards; the dried cuttings can be made into road base materials or green planting soil, truly achieving “zero mud pollution discharge”. The system has also passed ISO14001 environmental certification, adapting to strict environmental protection policies.
In addition, the KOSUN Machinery Horizontal Directional Drilling (HDD) Mud Recycling System features a compact design that significantly reduces the required footprint, allowing it to function fully even in space-constrained construction environments.
The core value of the KOSUN Machinery Horizontal Directional Drilling (HDD) Mud Recycling System lies in transforming mud from a “polluting waste” into a “recyclable resource.” Through breakthroughs in environmental compliance, cost optimization, and efficiency improvement, the system not only provides a compliant solution for HDD construction but also promotes the green transformation of the trenchless industry.