THE Guyana Water Inc (GWI) has commenced exploring the possibility of recycling the sludge which remains after the treatment of water, utilising polymers and geotextile containers, referred to as ‘geotubes’.   The company commenced testing in June 2015 under a programme being led by GWI’s Scientific Services Department, a GWI press release stated.
According to the company’s Senior Chemical Engineer, Deon Anderson, “The geotubes are capable of thickening and dewatering the sludge by trapping solid constituents and separating the liquid component through the walls of the fabric, with the aid of a polymer.”
This provides a dry product (25-30 per cent solids) that can be easily handled and disposed of, and this process would allow GWI to dispose of the solid sludge in a more efficient manner.  In addition, the separated water, which is removed from the sludge, can be re-used in the treatment process.
“Another benefit of using geotubes is the possibility of re-using the filtrate, which is water removed from the sludge in the treatment process. Ninety per cent of the sludge volume is reduced and recovered as filtrate,” stated Anderson, and “in addition to this, about eight per cent of treated water, which was once wasted through backwashing processes, can also be re-used in the treatment process, thus recovering significant costs.”
 ENVIRONMENTALLY-FRIENDLY
According to Anderson, the use of the geotubes is the most environmentally friendly option that GWI is currently exploring to manage the sludge which remains after the water-treatment process.
“Indeed, geotubes are the most feasible option, they offer the best economic benefits with high-quality filtrate for recycling,” stated the senior chemical engineer.
This new technology also allows GWI to continue to be in compliance with the environment protection policies and guidelines. The use of the geotubes is also in line with GWI’s sustainable management practices, as they allow the water removed from the sludge to be re-used in the treatment process.
The geotubes, which are currently being tested for effectiveness by GWI at the company’s Shelter-Belt Water Treatment Facility, Georgetown, are supplied by Tencate, a multinational company established in Almelo, The Netherlands.
The investment by GWI to employ the use of geotubes would cost in excess of GY$5M, which is the most cost-effective option the company has explored with regard to the disposal of sludge. Anderson also noted that “based on the supplier’s design of the geotube units, 2-4 geotubes would be recommended to treat the required amount of sludge, which would cost GWI US$5,000 per tube.”
The initiative would provide GWI with a more effective method of disposal – one that does not require the need to release significant amounts of sludge into the Irving Street Canal, the release concluded.