January 10, 2008

FGD Wastewater Hot Topic Hour Had New Insights and More than 70 Participants

January 10th there was a really informative discussion on FGD wastewater treatment.  There were 60 phones connected and probably close to 80 participants representing every segment, but with a sizable group of utilities represented. Here was the agenda.

     Agenda

  9:00     Introductions

  9:10     Brian Heimbigner, Siemens

  9:40     Tim Pickett, GE

 10:10    Anant Upadhyaya, Aquatech

 10:30    Phillip Elliot, Evonik

 10:50    Questions

Brian Heimbigner (Siemens) explained that they furnish both physical/chemical systems as well as biological. The addition of the biological adds another 70 to 100 percent to the cost. So it could cost twice as much if you need to remove selenium and mercury.

Here are typical effluent requirements.

Typical FGD Wastewater Treatment Requirements

Siemens has more than 15 systems in design or operation in the U.S. Wastewater treatment is not required for all systems. If there is a large waterway to which the effluent is discharged then final treatment may not be required.

Tim Pickett (GE) discussed the biological system and was barraged with questions. He assured the participants that the bugs could handle large amounts of chlorides and other contaminants. The main concern is to cool the wastewater down to 100°F to protect the micro-organisms. GE is a sub-contractor to Siemens. Brian testified as to the advantages of the GE biological approach.

Anant Upadhyaya (Aquatech) cited the advantages of the zero discharge system. The company has a 26 year history and is executing turnkey projects up to $120 million. The use of a crystallizer and spray dryer for the final steps results in only dry products for disposal and the potential for recovery of high purity water for recycle. There is also the potential to recover calcium or magnesium chloride for road use. There is a project at KCPL in the U.S. and a number of systems at Enel in Italy including two which are now operating.

Questioners wanted to know what happens to the mercury in the spray dryer. Anant indicated that a mist eliminator was effective on the mercury but did also state that the pre-treatment steps to reduce the mercury were also relevant.

Phil Elliot (Evonik) explained the basics of the two step wastewater treatment that Evonik (formerly Steag) uses. Activated carbon ties up the mercury which is then separated from the wastewater before the final dewatering step. Ninety-seven percent of the sludge is then recycled back to the coal pile. It is mostly calcium, silicon and other non- toxics. There is no rise in emissions from the recycling. There are big savings in landfill costs when only three percent of the sludge needs to be transported.

At the Herne plant the activated carbon is being further treated to separate the mercury for sale. This development project is underway and we will look forward to hearing about the results in the future.

We then opened the floor for questions. Pete Kutzora of We Energies described the following problem. An FGD wastewater system in operation for about one year has experienced scaling and fouling in the continuous backwash filters downstream of a pair of alkali-sulfide clarifiers. Have others experienced this problem and how was it resolved?

One suggested answer was to switch from hydrated lime to magnesium as the reagent. Pete is looking for answers. We would encourage our readers to respond with suggestions and we will post them in the Alert.

Paul Chu of EPRI asked about the experience and concern with mercury in the chemicals which are being purchased by the utilities. EPRI is just starting to investigate the problem. Pete Kutzora volunteered that their source of hydrochloric acid was quite pure but that there was up to 100 ppb of mercury in the sulfuric acid.

Bob McIlvaine posed another question. Using a water pre-scrubber and recirculating the solution, a power plant can make contaminated hydrochloric acid. Then with waste treatment the mercury can be isolated and the acid sold. Why not consider this alternative and generate a new revenue stream plus make coal greener? Chlor-alkali plants are big electricity consumers and mercury emitters. This question did not generate any responses. However there is a whole section in the FGD Decision Tree with details on this potential.

You can go directly to the power points in the FGD Decision Tree through the following links.

Brian Heimbigner – U.S. Filter/Siemens

Continuing Decision Process For: Products

FGD Wastewater Treatment, presented by Brian Heimbigner, Siemens, Hot Topic Hour January 10, 2008.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Siemens - Brian Heimbigner Hot Topic Jan. 10.htm
 

Tim Pickett – GE/Zenon

Continuing Decision Process For: Products

ABMet Advanced Metals Removal for FGD Wastewater Treatment, presented by Tim Pickett, GE Hot Topic Hour January 10, 2008.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/GE_Hot_Topic_Hour_1_10_08.pdf
 

Philip Elliott – Evonik Energy

Continuing Decision Process For: Products

FGD Wastewater Treatment Hot Topic Hour January 10, 2008. Presented by Philip Elliott

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Evonik Energy Services 01-08.pdf
 

Anant K. Upadhyaya – Aquatech

Continuing Decision Process For: Products

FGD Wastewater Treatment, Hot Topic Hour January 10, 2008, presented by Anant K. Upadhyaya

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/AIC-AKU-Presentation-011008.pdf

NO_x Reagents is the “Hot Topic” for January 17 at 9:00 a.m. CST

The “Hot Topic Hour” last year on NO_x Reagents was so hot that the scheduled 90 minute session stretched to more than two hours. But we encourage unstructured discussions and that is why we don’t set arbitrary time limits. To register for the January 17 Webinar session or to view the complete “Hot Topic Hour” schedule, click on:  http://www.mcilvainecompany.com/brochures/FGDnetoppbroch/Default1.htm .