Condition does not seem to be improving

THE LATEST STATEMENT: It appears that the water in Lake Rabon is getting worse. Lab results indicated that the level of geosmin in the lake has increased significantly from 33 ng/L (nanograms/liter) on July 8 to 434 ng/L on July 24. The level at which humans can taste and smell geosmin is 7-10 ng/L. We have been working with consultants and suppliers to identify the most effective treatment process to deal with the geosmin. As a result, we hope to start introducing a product called Earth Tech. We asked S.C. Department of Health and Environmental Control last Wednesday for a temporary permit on this process and we hope to hear from them this week. In addition to this, we have been testing various types and quantities of carbon. One variety called Hydrodarco, manufactured by the Cabot Corporation, seemed to work best at removing geosmin. It reduced the level from 432 ng/L to 35.6 ng/L. While that is still in the detectable range for humans (7-10 ng/L), we think a combination of this and the Earth Tech will finally solve the problem. We are in the process of ordering the carbon and engineering the delivery system. All of which will need an additional permit from SCDHEC. Again, we apologize for the length of time this process has taken. Please be assured that all available resources are being devoted to solving this problem. We ask for continued patience while we work through this event. - Laurens CPW

LCWSC Board hears about the science behind bad water.

 

 

 

Dealing with bad water can be a lot like an Advanced Chemistry lesson.

This is the culprit:

“Geosmin is an organic compound with a distinct earthy flavor and aroma produced by certain bacteria, and is responsible for the earthy taste of beetroots and a contributor to the strong scent (petrichor) that occurs in the air when rain falls after a dry spell of weather or when soil is disturbed.

“In chemical terms, it is a bicyclic alcohol with formula C12H22), a derivative of decalin. Its name is derived from the Greek γεω- "earth" and ὀσμή "smell".

“Geosmin is produced by the gram-positive bacteria Streptomyces and various cyanobacteria, and released when these microorganisms die. Communities whose water supplies depend on surface water can periodically experience episodes of unpleasant-tasting water when a sharp drop in the population of these bacteria releases geosmin into the local water supply. Under acidic conditions, geosmin decomposes into odorless substances.

“In 2006, the biosynthesis of geosmin by a bifunctional Streptomyces coelicolor enzyme was unveiled. A single enzyme, geosime synthase, converts farnesyl diphosphate to geosmin in a two-step reaction. Streptomyces coelicolor is the model representative of a group of soil-dwelling bacteria with a complex lifecycle involving mycelial growth and spore formation. Besides the production of volatile geosmin, it also produces many other complex molecules of pharmacological interest; its genome sequence is available at the Sanger Institute.

“Effects: The human nose is extremely sensitive to geosmin and is able to detect it at concentrations as low as 5 parts per trillion.

“Geosmin is responsible for the muddy smell in many commercially important freshwater fish such as carp and catfish. Geosmin combines with 2-methylisoborneol, which concentrates in the fatty skin and dark muscle tissues. Geosmin breaks down in acid conditions; hence, vinegar and other acidic ingredients are used in fish recipes to reduce the muddy flavor. Taste and odor compounds including geosmin lead to an unpleasant taste of drinking water which is perceived by consumers as an indication of poor water quality.” (Source: Wikipedia)

As Laurens CPW continues to battle the taste and odor problem in the drinking water, CPW General Manager John Young issued this statement: “Again, we apologize for the length of time this process has taken. Please be assured that all available resources are being devoted to solving this problem. We ask for continued patience while we work through this event.”

It has been a summer of complaint for the Laurens CPW and its water customer, the Laurens County Water and Sewer Commission, as ill-tasting and ill-smelling water has been reported – the source being Lake Rabon.

In the past 3 years and 2020 to date (1 month of the fiscal year), LCWSC has fielded 1,204 customer complaints – almost all happening in the summer. It’s the natural life-cycle of a standing body of water – algae grows and dies, chemicals are released, treatment options are weighed. Then, it all seems to sort itself out.

That’s what’s happening in Laurens (LCWSC also buys water from Clinton and Greenville). “CPW is staying in contact with us,” LCWSC Executive Director Jeff Field told the agency’s board last Tuesday. “They are bringing in carbon.”

A “carbon sponge” is a known treatment for geosmin, Field said, but the “silver bullet” is ozone. That’s why LCWSC is asking the US Department of Agriculture to loan it more money to build its proposed Lake Greenwood Water Treatment Plant – the additional expense will be for an ozone treatment system.

Right now, LCWSC does not generate its own treated water – it relies on Laurens, Clinton and Greenville to produce a product free of contaminants, odor and bad taste. Field said, “We have these problems, then there’s a lull, then it goes by.”

A lake producing geosmin is a perfectly natural chemical occurrence, and the water is safe to drink, it’s just “aggravating,” the board was told.

Spartanburg and Anderson had geosmin problems in the recent past. The human nose is sensitive to geosmin at 5 parts per trillion – the board was told in Anderson’s case, it was measured at more than 100 parts per trillion, from Lake Hartwell. It was one of the highest measurements ever, the board was told.

Geosmin is a chemical that the algae produces. Another chemical, MIB, can come in the fall, and it is much harder to deal with, the board was told.

Most geosmin problems that become widely know are at just over 20 parts per trillion, the board was told. Most of the complaints fielded by LCWSC personal are “dirty water complaints,” the board was told, and most come in August.

My Clinton News

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