AD Plant Smell

[Wastexprt]

No one disputes your comments regarding the environment between anaerobic and aerobic, however this thread was started regarding the odour around a plant and what regulations are in place to prevent this.

AD permit condition

3.3 Odour
3.3.1 Emissions from the activities shall be free from odour at levels likely to cause pollution outside the site, as perceived by an authorised officer of the Environment Agency, unless the operator has used appropriate measures, including, but not limited to, those specified in any approved odour management plan, to prevent or where that is not practicable, to minimise, the odour.
3.3.2 The operator shall: (a) maintain and implement an odour management plan; (b) if notified by the Environment Agency that the activities are giving rise to pollution outside the site due to odour, submit to the Environment Agency for approval within the specified period, a revised odour management plan; (c) implement any approved revised odour management plan from the date of approval, unless otherwise agreed in writing by the Environment Agency.

 

[thesilentone]

My original comment: If you are handling anything that is ' waste ' there is smell, AD Plant or not, please accept we cannot live in a smell-free world.

The odour management plan allows for this, controlled by the number of odour units, if your unhappy, they may call in the ' sniffers '

 

[Wastexprt]

My original comment: If you are handling anything that is ' waste ' there is smell, AD Plant or not, please accept we cannot live in a smell-free world.

The odour management plan allows for this, controlled by the number of odour units, if your unhappy, they may call in the ' sniffers '

Indeed, it does state minimise as opposed to eradicate although odour units aren't stated in permits, yet

 

[thesilentone]

units aren't stated in permits, yet

they are stated in the Odour management plan....

 

[Wastexprt]

they are stated in the Odour management plan....

Oh. The ones I've done haven't included odour units as the permit doesn't refer to a level, just the perception of odour nuisance by an EA officer.

Best keep an eye out for one of these

 

[thesilentone]

look up Airshed...........

 

[Wastexprt]

look up Airshed...........

Aha, odour units for Odour Impact Assessments, yes. I've not been asked by the EA to put odour units in an OMP though.

 

[thesilentone]

A typical summary OIA (Odour Impact Assessment) below. This will have an influence on planning and the EA (should have) and should form the basis of the Odour Management Plan.

There are a few potential problems.
1) The nearest met office centre for data (wind speed/direction etc) could be miles away.
2) The sniffer is a human being
3) The advice in this report may not suit the planners. (eg the hight of the dispersal flu)

All in all, putting these aside, this is a very comprehensive way of ensuring we don't end up with smelly plants around a high density population.

1) Odour Impact assessment
2) Practical solutions (biofilters, buildings under negative pressure, dispersal flue's etc)
3) Odour management plan.

The public do not want to tolerate smell, however, we cannot be completely odour free.

We create waste (in huge volumes) then expect it to disappear.

xxxxxxxxxxxxxx Ltd proposed to build and operate an organic waste treatment process at xxxxxxxxxxxxx processimg 35,000 tonnes of municipal solid waste (MSW) per annum. The MSW would be collected within the xxxxxxxxxxx area. The process would treat mixed garden and kitchen MSW by dry anaerobic digestion (AD) followed by in-vessel composting (IVC). All operations would be conducted within enclosed buildings held under negative pressure. The proposed AD process was based on dry fermentation which allows the collection of biogas, which can then be used to generate electricity. The waste residues from the AD process would then be treated in a series of IVC tunnels to meet the requirements of the Animal By-Products Regulations. Odour from the building would be captured and treated using a bio-filter. Following public consultation with the local community, xxxxxxxxxxxxxxxxLtd appointed The xxxxx to conduct an odour impact assessment for the proposed scheme and to advise on what further mitigation measures might be required to protect local amenity. The main public concern was the nearest dwellings were already affected by odour from the adjacent wastewater treatment works (WwTW) operated by xxxxxxxxxxxxxxxxxxxxxxx were about to initiate statutory nuisance proceedings against xxxxxxxxxxx The existing environment therefore had very limited capacity to receive additional odour without causing further loss of amenity. Rather than seeking to quantify baseline odour from the WwTW, the approach adopted by xxxxx was to conduct dispersion modlling for the proposed AD process and to use the results to help specify the level of abatement necessary to ensure that the AD/IVC process odours would be insignificant at all residential receptors. The design for odour abatement plant was based on the aim of ensuring that odour from the AD/ IVC process would not exceed 1.0 OUE/m3 1 hour 98%ile at the nearest residential area. Odour impacts were assessed in accordance with Environment Agency draft Guidance (H4). Emission dispersion was predicted using a dispersion model (ADMS 4.2) and five years of hourly sequential meteorological data from xxxxxxxxxx, the nearest Met. Office site with suitable observations. A model sensitivity analysis was conducted for release conditions, surface roughness, building effects and meteorological variability. The dispersion model results indicated that a high level of odour abatement would be required if the emissions were to be released from the surface of the bio-filter. However, covering the bio-filter and releasing from a stack would increase the efflux velocity and the initial release height, improving dispersion. This approach would ensure that odour was unlikely to exceed 1.0 OUE/m3 1 hour 98%ile at the nearest residential area, without requiring a very high level of odour abatement within the plant. Additional mitigation measures included improved containment of the waste reception hall to reduce the rate of odour emission, and a door management system within the building to provide an effective airlock. The assessment also considered the potential impacts of NOx from the gas engines.

 

[Wastexprt]

I'm not disagreeing with you at all. Only saying that in the OMPs I've done for permit holders as part of EA permits, I've never been asked for an Odour Unit level to be included. All the other measures, absolutely, but not odour units.

When I was an EA officer I had my nose 'tested' and have a an 'average' sense of smell, which is what they required to assess odour nuisance.

 

[Fowler VF]

If anyone needs to buy an air scrubber unit I have several large (from 10 to 30,000 cfm) ones available secondhand. Designed to be operated in pairs, one with an acid solution to remove things like amines and one on alkali with an oxidising agent (we used chlorine dioxide) to remove acidic smells like mercaptans. Exhaust air from scrubbers can go to atmosphere or be ducted to a biofilter for further treatment.

Biofilter design and operation is a tricky black art. The biofilter medium is designed to be of a type that encourages bacteria to grow on it that will "eat" the smelly molecules. Common mistakes made are, biofilter too small and not enough residence time (needs up to a minute), biofilter medium uneven, biofilter medium degrades and creates its own smell, biofilter medium too wet or too dry, inconsistent feed of smelly air to the biofilter (the bugs need a steady constant feed of the same smell molecules in order to stay alive and do their job), biofilter too hot or too cold for the right bugs, chemicals in the exhust gas kill or inhibit the bugs.

 

[Funny Farmer]

We had digestate spread on our fields for free but we'll not have it again the stench was awful and the tanker was so huge I still feel the wheelings 2 years later despite sub soiling them twice. I think they use such big tankers to cut down transport costs as all the closest farms to the plant won't or can't take any more .

 

[thesilentone]

We had digestate spread on our fields for free but we'll not have it again the stench was awful and the tanker was so huge I still feel the wheelings 2 years later despite sub soiling them twice. I think they use such big tankers to cut down transport costs as all the closest farms to the plant won't or can't take any more .

Generally the ground pressure per square inch is less with a bigger tanker due to the running gear.

As a farmer, surely the Nutrient, and long-term benefit to your land is more important than short term odour ?

See page 16:

http://www.zunhammer.de/sites/default/files/zunhammer_final_print.pdf

 

[Funny Farmer]

Generally the ground pressure per square inch is less with a bigger tanker due to the running gear.

As a farmer, surely the Nutrient, and long-term benefit to your land is more important than short term odour ?

See page 16:

http://www.zunhammer.de/sites/default/files/zunhammer_final_print.pdf

We had a sample analysed and the benifit in our case would not have paid for the transport and spreading never mind the cost of subsioiling.

 

[thesilentone]

We had a sample analysed and the benifit in our case would not have paid for the transport and spreading never mind the cost of subsioiling.

One of the great things about Digestate is that it is a known value. NPK volumes are either documented, or the sample is analysed to be exact.

Did you know what you were spreading on your land ?

 

[Courier]

Neighbour has just got planning through for Biogas plant to feed gas direct into town gas supply - good luck to him.

 

[Lazy Sod]

The trouble is that the Warminster biogester was built right at the entrance to the town, hardly a welcoming sight for visitors. The nearest house is downwind and only about 250 yards away, not counting the former farmhouse that belongs to the site and is either occupied by a plant operative or maybe rented out.

Somebody has a letter in the local paper this week, complaining about the smell. The writer thinks that it's a sewage plant.

 

[Funny Farmer]

The time for complaining is before they build it! , they wanted to put one up round here and a very well organised group helped ensure it got rejected but it was surprising to the the group the sheer apathy of people when they knocked on doors to talk to them about opposing the plant .

 

[thesilentone]

The time for complaining is before they build it! , they wanted to put one up round here and a very well organised group helped ensure it got rejected but it was surprising to the the group the sheer apathy of people when they knocked on doors to talk to them about opposing the plant .

Because people did not want to object, or maybe even supported green energy being produced in their area, you label them as ' apathetic '

Do you class your self as a NIMBY, or just very bad mannered ?

 

[kill]

We had digestate spread on our fields for free but we'll not have it again the stench was awful and the tanker was so huge I still feel the wheelings 2 years later despite sub soiling them twice. I think they use such big tankers to cut down transport costs as all the closest farms to the plant won't or can't take any more .

It's not just the stench as one AD plants sludge pond has people living near that are all being affected by blistering in and around their mouths and are blaming gas released by the sludge.

 

[thesilentone]

It's not just the stench as one AD plants sludge pond has people living near that are all being affected by blistering in and around their mouths and are blaming gas released by the sludge.

Interesting, could you please give more details, plant location etc?