The largest lagoon liner
A 350-acre geomembrane liner project was completed last year in Kazakhstan—in record time.
An oil company in Kazakhstan planned to line a 350-acre (1,400,000 square meters) lagoon to contain process liquid waste, and was resigned to a three-year time frame for construction in the rugged and wintry climate of the former Soviet Socialist Republic. Geosynthetic Technology Ltd. (GT), Colchester, England, braved severe dust storms and occasional flooding from April to October 2011, but managed to install what is called “the world’s largest lagoon liner” in seven months. “I have been working in geomembrane engineering for nearly 40 years and have never seen a geomembrane installation more professionally performed,” says GT chairman John Alexander. “The pace was breathtaking.”
GT was hired to manage all aspects of the lining project. The company has more than 40 years of experience with geomembrane engineering, specializing in lining project management internationally. Itemized preparation for the project included: evaluation and testing of geomembrane lining materials; reviewing manufacturing resources; training and certifying on-site labor; geomembrane installation planning; and quality assurance procedures.
GT commenced installation in August 2010, with the objective of testing its rapid installation plan over about 10 percent of the total lagoon design area. Despite hot weather (up to 38 C, 100 F), the trial area was completed ahead of schedule. The client noted the rapid progress and authorized the whole of the remaining area for installation on the same fast-track basis from April to October, 2011. The work was completed by the end of August 2011. Every seam was tested and all quality procedures completed.
Planning particulars
A “right first time” failsafe approach was taken by GT regarding manufacturing quality, given the distance of more than 2,000 miles from the liner manufacturing plant to the job site, and the tight installation program. Raw material tests certificates were provided and checked for each batch of polymer used, and rolls of sheet manufactured from each polymer batch were allocated a unique reference number.
Every roll was tested at the production plant for compliance with specified basic physical properties. A sample of each thickness from every batch was selected at random by GT and submitted to an independent laboratory for repeat conformance testing of basic physical properties. GT also arranged for various reference tests, such as surface friction, multi-axial elongation and coefficient of thermal expansion, conducted in an independent U.S. laboratory. The results of all testing were incorporated into a quality assurance report for the client.
For transport, the two most important factors considered for container freight were the size of the rolls (to enable best use of container volume) and the method of loading and unloading without damage. GT determined that rolls of 1.00mm (40-mil) gauge in a sheet size of 5.8m (19ft) × 200m (656ft), and rolls of 1.5m (60-mil) in a sheet size of 5.8m (19ft) × 135m (443ft) would enable 16 rolls packed per container. In each case, a symmetrical 4 × 4 formation was used, to eliminate the risk of crushing or coming loose during the 2,000-mile journey. A spike, manufactured for the purpose, was bolted to a forklift truck; it was inserted through the central core of the rolls for loading and unloading.
Geomembrane installation
An inventory of specialized equipment, welding machines, spare parts, lifting frames and quality control equipment was assembled by GT and shipped to the job site. An air-conditioned site laboratory and workshop was established. GT calculated that it would be necessary to operate with three welding crews each day on 12-hour shifts, seven days a week, for continuous sessions of 30 days on/30 days off per rotation crew. The company also determined that it would be necessary to have at least one of its senior technicians on-site on a rotation basis throughout the entire project.
To facilitate a smooth startup and good communication, two Kazakhstan installers were selected to travel to GT headquarters in England, where they underwent intensive training, including on-site work in varying weathers for three months. Training included learning job-specific English words such as weld, deploy, and quality control. At the completion of training, the workers were issued certificates of competence in welding. The availability of the trained Kazakhstan personnel, under the management and organization of GT technicians on site, prompted an efficient start.
Within days of commencement, an output of 20,000m2 (215,280ft2) per day was consistently achieved when weather conditions permitted. During the seven-month installation period, the work crews experienced two flash floods, several dust storms, frosty mornings, and high temperatures exceeding 40 C (104 F). There were days when no installation was possible, which made it even more imperative to achieve high output during good weather to complete the job.
Quality control
Every seam was tested qualitatively by an air-pressure method. Each seam weld actually included two parallel welds with a gap between them. The end of the seam run—up to 200m (220 yards) long—was clamped and then air was pumped into the weld gap to inflate it to a predetermined pressure.If this pressure is maintained for a specified time, the seam is verified as airtight. In the event of a drop in pressure, the leaking air was located by sound and the leak patch-welded.
At the start of each shift or change of welding machine setting, a sample seam tab was submitted to the on-site laboratory for destructive testing. The mode of failure of the seam was also examined, and the location of all rolls and seams were noted on an as-built drawing. The onsite-based quality control function was performed by English-speaking personnel to ensure that nothing would be “lost in translation.”
“This geomembrane lining project was groundbreaking in many respects,” said GT chairman Alexander. “Its sheer scale of 1,400,000 square meters is awesome and is, by any standards, the largest lagoon lining ever undertaken anywhere in the world. The speed of liner installation, together with the high quality standards maintained throughout the work, has set new standards in geomembrane engineering.”
