The disposal of waste drilling fluids & muds has traditionally been by tanker to landfill sites but there are now few locations with the equipment to process waste fluids and as fluids are no longer permitted to be disposed of to landfill, the cost of transport to suitable processing sites is very high. This situation means that it is now often more economical, and nearly always more environmentally acceptable, to treat the waste mud on site so as to reduce the volume of liquid waste being sent off the site by tanker.
Legislation was introduced in 2001 to implement the European Landfill Directive, which restricts the disposal of fluids to only a few licensed landfill sites in the UK and elsewhere through Europe.
PSD are specialists in the cleaning of waste mud and we are often able to turn waste mud or slurry into a considerably reduced volume of solids that can be disposed of at landfill and practically clear water that is able to be discharged to the sewer system.
One method of treatment for waste fluids is to flocculate and dewater so as to produce a semi-solid sludge for off-site disposal by tipper truck and a near clear centrate which can usually be safely disposed of to the public sewer system or to streams, rivers, canals, lakes or to the sea with the appropriate consents. Flocculation and centrifuging is most economical when there is a continuing requirement for waste mud disposal during the progress of the job or where there is a large volume of surplus mud, such as at the end of the work. Small or medium sized centrifuges can typically process 8 to 10m3
/hr of flocculated waste mud, our large S4-1-G centrifuges
can handle up to 40m3
/hr of these materials and the S5-1-G centrifuges
have almost double that capacity.
Another method of eliminating the requirement for disposal by tanker, particularly where waste mud volumes are not large, is mud solidification. This process uses a specialist water absorbent polymer, POLYSWELL, which is mixed with the mud. Some of the water in the mud is chemically bound to the polymer thereby reducing the free water content of the mud and making it ‘thicker’. The more polymer that is added the more water becomes bound to it and the mud becomes thicker, drier and stiffer. The final ‘solidified’ mud can be handled as a solid rather than a liquid and can normally be disposed of to a ‘solids’ landfill tip.