GWI tackling sludge problem on Irving St

Water utility, the Guyana Water Incorporated (GWI), is exploring the possibility of recycling the sludge which remains after the treatment of water.

This would also help relieve a clogging problem in the Irving Street Canal caused by the release of the sludge by GWI.

In a statement on Tuesday, GWI said that it commenced testing in June 2015 with the use of polymers and Geotextile containers, referred to as “Geotubes.” The programme is being led by GWI’s Scientific Services Department and according to 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.”

The statement said that this provides a dry product - 25-30% solids - that can be easily handled and disposed of. It said this process would allow GWI to dispose of the solid sludge in a more efficient manner.

In addition, the water 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. 90% of the sludge volume is reduced and recovered as filtrate,” Anderson said.

“In addition to this, about 8% of treated water which was once wasted through backwashing processes, can also be reused in the treatment process, thus recovering significant costs,” he added

According to Anderson, the use of the Geotubes is the most environmentallyfriendly 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 recycle,” he said.

“This new technology also allows GWI to continue to be in compliance with the environment protection policies and guidelines,” he added.

The statement said that the use of the Geotubes is also in line with GWI’s sustainable management practices. The Geotubes, which are currently being tested for effectiveness by GWI at the company’s Shelter-Belt Water Treatment Facility in Georgetown, are supplied by Tencate, a multinational company established in Almelo, the Netherlands.

GWI said its investment in the use of Geotubes would cost in excess of $5 million, which is the most cost-effective option the company has explored with regard to the disposal of sludge.

“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$5000 per tube,” Anderson said.

The statement said that 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.