Flyash Ponds and Wastewater Treatment was the Hot Topic Yesterday

A high energy discussion resulted from presentations by four experts with complementary experience. We learned that measuring metal emissions in water is challenging. Many utilities are over reporting their emissions. This is not a good time to be over reporting, since it is the “Perfect Storm.” The speakers pointed out that we have new proposed byproduct regulations, wastewater regulations, MACT standards and a very prominent dam collapse. There are physical and biological ways to remove the pollutants, but the issue is cost.

One problem is that historic emissions will not be future emissions. If the new FGD system wastewater is added to the sluiced flyash, you have more contaminants which previously were emitted to the air and dispersed over a long distance. With potential mercury capture with carbon and this product mixed with the flyash, you could have mercury levels 10 times higher than at present.

McIlvaine challenged the group to think outside the box. Maybe inhibited oxidation with chemical fixation of the sludge, an old technology, should be reincarnated. What about using an HCl pre-scrubber and capturing all the heavy metals in the purification of the 30 percent acid?  In fact, why not add all the flyash to the hydrochloric acid scrubbing loop and leach out the metals?

Naomi Levy’s, Infilco Degremont presentation included treatment options for both the flyash and flyash pond leachate. She discussed Infilco’s DensaDeg Clarifier. According to Naomi, the DensaDeg clarifier has the following advantages:

§  Superior quality of the effluent.

§  The rise rate is very high, resulting in a smaller footprint. A space savings of 1:10 can be expected relative to a conventional clarifier.

§  The bottom sludge is dense, resulting in significant savings on sludge handling and dewatering cost.

§  Separate sludge thickener is not required.

§  Can tolerate upsets and contaminant fluctuation.

§  Lower chemical consumption.

§  Hundreds of long term successful installations worldwide.

Scott Murphy of Arcadis discussed flyash ponds and wastewater treatment issues. Metal contaminants vary by type and quantity. Scott displayed the following:

                                            Metals Treatment Alternatives Matrix

IX = Ion Exchange

Bill Shaw of Veolia discussed the following:

Advantages of CoLD™ Vapor Compression Process are:

• No chemicals, less sludge,
• Lower energy requirement,
• Simple system, less operator attention,
• Robust system, and
• Lower capital cost.

CeraMem™ Ceramic Membranes for MF and UF applications provide:

• Long life – Proven life > 3 years in industrial applications.
• High temperature – Up to 200° both continuous and for cleaning.
• Chemical cleanability – can take pH 2 – 13 cleaning solutions.
• Mechanically robust – can take high operating and backpulse pressures. Backpulsing reduces the need for chemical cleaning and has been proven to produce higher fluxes.
• Absolute TSS barrier. Typically needs less polymer dosing into clarifiers before the membrane plant.

Packaged Actiflo^® Clarifier has the following features and benefits:

• Turbidity removal >90 percent,
• Reacts quickly to changing raw water quality,
• Compact design, much smaller than conventional clarifiers,
• Pre-engineered, minimal civil engineering, short lead times, fast commissioning, and
• Over 400 Actiflo™ installations worldwide.

William Kennedy of Orion Engineering and Ivan Cooper, Terracon Consultants offered the following:

• Bench scale and pilot scale testing is critical.
• Chemicals and coal variability impact treatment.
• There are many ways to achieve effluent concentration reduction and detailed cost evaluations are needed.
• There is need to understand process chemistry.
• Analytical labs may be challenged, by matrices interference and low discharge limits v. detection limits.

The bios, abstracts and photos can be viewed as follows:

BIOS, PHOTOS, ABSTRACTS - JANUARY 21, 2010.htm

The individual slides are located in our FGD Decision Tree as follows:

Naomi Levy – Infilco Degremont

Scott Murphy – Arcadis

Bill Shaw – Veola

William Kennedy, Orion Engineering and Ivan Cooper, Terracon Consultants

FGD Continuing Decision Process For: Solutions

Fly Ash Ponds and Wastewater Treatment Issues, presented by Naomi Levy - Infilco Degremont. Hot Topic Hour January 21, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Naomi Levy Infilco - 01-21-10.pdf
 

Fly Ash Ponds and Wastewater Treatment Issues, presented by Scott Murphy, Arcadis. Hot Topic Hour January 21, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/Scott Murphy - Arcadis 01-21-2010.pdf
 

Zero Liquid Discharge Systems for Power Plants, presented by Bill Shaw, Veolia. Hot Topic Hour January 21, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/William Shaw - Veolia Water - 01-21-10.pdf
 

Ash Ponds and FGD Wastewater Treatment, presented by William Kennedy, Orion Engineering and Ivan Cooper, Terracon Consultants. Hot Topic Hour January 21, 2010.

http://www.mcilvainecompany.com/FGD_Decision_Tree/subscriber/Tree/DescriptionTextLinks/William Kennedy - Orion Engineering - 01-21-10.pdf