From experience the issue with repeated application of wood ash is the accumulation of cadmium which is different as opposed to the lead and arsenic from coal.
The PAH generated will be dependent as much on the efficiency of the design of the fire as will the material you are burning (coal or wood). The PAH by-products are formed during the thermal decomposition of the coal or wood in the fire, if the fire is not well designed, much of the PAH and associated by-products are lost to the atmosphere to be deposited on someone else property.
Wood is more complex than coal, as coal has undertaking the process of coalification which takes it from Lignite through to anthracite.
Woods vary in their internal structure and some are hopeless for burning, so you would get different relative efficiencies of combustion for different wood types. You also need to take into account the moisture content which will affect the generation of tars. It is covered a little in the attached link http://www.forestry.gov.uk/pdf/eng-woodfuel-woodasfuelguide.pdf/$FILE/eng-woodfuel-woodasfuelguide.pdf
Smokeless fuels such as coke, should leave behind little PAH, as it is mainly carbon (and entrained inorganic substances) and has a spongy residue allowing improved air diffusion.
With efficient complete combustion you should get little PAH generated, so you may need advice from Bear Grylls for this!
Best Regards
Russell
Dr Russell Thomas
Technical Director
Kings Orchard,
1 Queen St, Bristol,
BS2 0HQ
Direct tel: +44(0) 1179 306374
Switchboard: +44(0) 1179 306200
Mob: +44(0)7879 602509
www.wspgroup.co.uk
www.pbworld.com
Check out our Linkedin page
Follow us on Twitter
Brownfield Briefing Awards 2014 for ‘Best Conceptual Design’ winner (Parsons Brinckerhoff)
Confidential
This message, including any document or file attached, is intended only for the addressee and may contain privileged and/or confidential information. Any other person is strictly prohibited from reading, using, disclosing or copying this message. If you have received this message in error, please notify the sender and delete the message. Thank you.
Parsons Brinckerhoff Ltd, Registered Office: Amber Court, William Armstrong Drive Newcastle upon Tyne NE4 7YQ. Registration number 2554514 England and Wales.
If possible, please consider saving paper by not printing your e-mail.
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Taylor, Christopher
Sent: 21 April 2015 09:17
To: [log in to unmask]
Subject: Re: Wood ash vs coal ash
I think it's the potassium they are after. I know the main source of potash these days is from mined marine deposits. I just have concerns regarding the PAHs, and the accumulation of PAHs from constant burning and spreading ash over the years.
Regards
Christopher Taylor
Enforcement Officer
Regulatory Services
Brent Council
Tel: 020 8937 5159
www.brent.gov.uk
-----Original Message-----
From: Contaminated Land Management Discussion List [mailto:[log in to unmask]] On Behalf Of Clive Williams
Sent: 21 April 2015 09:01
To: [log in to unmask]
Subject: Re: Wood ash vs coal ash
I would imagine the conc of PAH would be much higher in coal ash given the massive concentration factor in a 1m seam of coal coming from up to 30m of plant stuff depending on the type of coal.
What is the benefit of wood ash spreading, is it the phosphorous? that you can extract from wood ash by soaking it.
Cheers
Clive
--
The use of Brent Council's e-mail system may be monitored and communications read in order to secure effective operation of the system and other lawful purposes.
______________________________________________________________________
NOTICE: This communication and any attachments ("this message") may contain confidential information for the sole use of the intended recipient(s). Any unauthorized use, disclosure, viewing, copying, alteration, dissemination or distribution of, or reliance on this message is strictly prohibited. If you have received this message in error, or you are not an authorized recipient, please notify the sender immediately by replying to this message, delete this message and all copies from your e-mail system and destroy any printed copies.
|