|
Aqua
Freed® Case Studies
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The Aqua Freed® well rehabilitation process has been extremely successful in restoring lost capacity to more than 5000 wells worldwide, during the past 18 years. Below is a small sampling of before and after results from the Aqua Freed® well rehabilitation process. Case
Study 1
Well 9 was installed in 1964 but was never used due to a low yield (110 gpm). In April of 1997 Well 9 was redeveloped using the Aqua Freed® process followed by surge block agitation. Prior to redevelopment well #9 was televised and pump tested. The video inspection revealed a significant amount of encrustation on the well screen. The interval between 40 ft bg. and 54 ft bg. was extensively clogged with only the vertical supports visible. From 54 ft bg. to 69 ft bg. the screen was less clogged. The results of the pre and post-redevelopment efforts are summarized below:
Well 9 was pumped at a rate of 260 gpm for a 24-hour period. The specific capacity values at the completion of the test were two times greater than the original specific capacity and three times greater than .the pre-redevelopment specific capacity. The long term recommended pumping rate of well 9 is 225 gpm.
Case
Study 2
In April of 1997 well # 8 was redeveloped using the Aqua Freed® process followed by mechanical development (surging and pumping). Well 8 was televised prior to redevelopment. The video inspection revealed a significant amount of encrustation along the surface of the well casing and screen. Most of the slot openings in the screen were completely clogged with buildup. The annulus between the inner and outer well casing was grouted prior to redevelopment. The results of the pre and post redevelopment data are as follows:
Well 8 was pumped at a rate of 335 gpm for a 24-hour period. The specific capacity value for well 8 is greater than the initial specific capacity of 9.5gpm/ft at 275 gpm. The post treatment video survey revealed a considerable improvement in the condition of the screen.
Case
Study 3
The original specific capacity of well # 4 was 22.2 gpm/ft with a pumping rate of 1000 gpm. By 1985 the specific capacity had declined to 8 gpm/ft with a pumping rate of 200 gpm. Since 1985 well # 4 had been rehabilitated 5 times. Each rehabilitation attempt was successful in re-gaining some of the lost capacity; however there has been a declining trend in specific capacity since installation. Well #4 has historically exhibited high levels of iron and manganese. In 1996 the well was modified to isolate the lower 20 ft. of well screen to prevent the upward migration of water from the lower portion of the well. Rehabilitation methods consisted of chemical treatments combined with surging. In April 1999 well #4 was rehabilitated using the Aqua Freed® process combined with Sonar Jet and mechanical surging. The pre-treatment video inspection revealed that the well screen was completely clogged with mineral and biological deposits. The results of the pre and post pumping tests are as follows:
Note:
A specific capacity of 27.6 at 210 gpm was recorded at the completion
of mechanical development. This reading was taken with the intake
of the pump assembly at 107 ft bg. This data indicates that
well # 4 has a higher specific capacity in the lower portion
of the well and is a potential candidate for a suction flow
control device. It should also be noted that the post treatment
video inspection indicated the well screen was clean and the
build up was completely removed. Case Study 4
During the month of April 1996 the Goffle Well was rehabilitated using the Aqua Freed® process followed by mechanical surging. Prior to rehabilitation the well was televised to identify fractures. Major fractures were noted at 49, 91, 118, 141, 195 ft bg. After completion of the video survey the open-hole was wire-brushed followed by the Aqua Freed® process. Carbon dioxide was directed into each fracture with the exception of the upper most fracture at 49 ft bg. A cable-tool machine was used to mechanically surge and develop the well following the Aqua Freed® process. All pumping test were conducted by LBG. Although there were no pre-treatment step rate pumping tests available for this well immediately preceeding redevelopment, results were available from 3 years prior. It is naturally assumed that the condition of the well had deteriorated below that which is represented in the data from the prior 3 years.
In May 1996 a second post-treatment pumping test was conducted, a design pumping rate of 300 gpm was recommended with a maximum pumping level of 48 ft bg.
Well 9A had experienced a significant loss of capacity since construction in 1987. The loss of capacity was attributed to iron related bacteria. This well had been redeveloped several times since installation with traditional chemical treatments (acid, HTH, etc.) combined with swabbing. Typical redevelopment would take approximately 2-3 weeks to complete. The chemical treatments were successful in re-gaining the loss capacity, however, longevity was a problem. The conventional chemical redevelopment process would last approximately 1 year, before the specific capacity values declined to a point the well was shut off due to energy cost. In May of 1995 well 9A was rehabilitated using the Aqua Freed® process combined with single/air-lift. Prior to rehabilitation the well was televised, the video survey revealed a significant amount of plugging throughout the entire well screen. Carbon dioxide was injected over a two-day period and directed to two injection points in the well screen. Mechanical development was completed in 32 hours. The entire project was completed in 8 days. The results of the rehabilitation process are as follows:
The
post rehabilitation video showed the plugging on the well screen
had been removed. The well maintained its post rehabilitation
specific capacity for a period of approximately two years before
it began to decline, illustrating the superior longevity of
Aqua Freed® compared to conventional cleaning methods. City
of Sioux Falls, South Dakota
United
Water of New York
Wishard
Hospital of Indiana Super
Fund Site in Northeast |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||