Posted on May 28, 2011

In a Qatar first for eco-friendly wastewater treatment, a contracting firm is turning 1.4mn gallons of sewage from one of its labour camps into as much recycled water per month and saving about QR2.4mn a year. “There is no need to remove sewage in trucks and we save up to 20% of fresh water,” Gulf Contracting Company (GCC) operations manager Andrew Ford told Gulf Times during a visit to the camp at Umm Salal.

The human waste and all other liquid waste generated by 1,600 workers, living in one section of the camp, are being put to highly productive use through technology from Canadian company Bionest. “Up to 20% of the recycled water is used in the camp for toilet flushing and urinals and the rest is transported to our work sites in tankers for use in a host of construction related activities,” Ford explained.

The first Bionest system was set up in the camp for 970 workers in October 2010. The second, for 630 men, followed in January this year. The total cost came to QR3.5mn. “Earlier, we used to transport sewage in nine to 10 trucks daily from the camp,” recalled the official. GCC is currently planning to install the Bionest system in another section of the Umm Salal camp to cater to 3,500 workers, and at a camp at Al Khor for 1,500 men.

Among the salient features of Bionest are that the biological system does not require sludge removal, is odourless, and could be completely installed underground. “The unit at my home in British Columbia has not been desludged in 14 years,” Bionest Middle East managing partner Robert N Lord said. If the purified water is reused, the system usually pays for itself in less than two years. “A QR1.3mn above ground 100 cu m system for 400 to 500 people pays for itself in 16 months, whereas a below ground system costing QR1.7mn, would complete the payback in 20 months,” Ford said.

The Bionest wastewater treatment system, also certified for use in Canada, the US, the Caribbean, Central America and Europe, meets global treated effluent standards, according to Lord. At the core of the Bionest system is a submerged fixed film reactor using a ribbon-shaped non-biodegradable polymer media. The whole treatment train consists of a settling tank, the bio-reactor with aeration and disinfection. The biomass (good bacteria) develops and firmly attaches to both sides of the media. The major portion of the reactor is aerated through linear air pumps and fine bubble air diffusers, which provide ideal conditions for better treatment.

In the remaining portion of the Bionest reactor, a high level of dissolved oxygen assists the oxidation process, in a calmer environment, ensuring no solids will escape and the final effluent will be colourless and odourless. To bring the treated effluent to a reuse quality, a final disinfection is required. Chlorination, ultraviolet, or ozonation are among the options. Bionest, represented by GCC in Qatar, also offers Oasis mobile wastewater treatment solution, housed in standard 40ft containers, for purchase and/or lease. A demonstration unit installed at Doha Golf Club until recently was capable of processing up to 8,000 litres of wastewater daily with power requirement of just 630W for three linear air pumps.


source: Gulf Times

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