Dr Andrew McLeod
@biosolids-andy.bsky.social
Consultant in Bioresources http://linkedin.com/in/andrewmcleodphd
I see no evidence that the cited report was suppressed. Either way, the UK water sector’s Chemical Investigation Programme (CIP) gives transparent, open-source analysis of all these substances in #biosolids. It is an infinitely more reliable and representative resource ukwir.org/sign-up-and-...
March 22, 2025 at 1:40 PM
I see no evidence that the cited report was suppressed. Either way, the UK water sector’s Chemical Investigation Programme (CIP) gives transparent, open-source analysis of all these substances in #biosolids. It is an infinitely more reliable and representative resource ukwir.org/sign-up-and-...
This study is based on frozen samples of soils & liquid #SewageSludge from trial plots in the mid-90’s. App rates & #biosolids incorportation depth are not representative of modern 🇬🇧 #biosolids use. The #Sludge itself was intentionally modified to exceed regulated contaminant levels…
March 22, 2025 at 12:56 PM
This study is based on frozen samples of soils & liquid #SewageSludge from trial plots in the mid-90’s. App rates & #biosolids incorportation depth are not representative of modern 🇬🇧 #biosolids use. The #Sludge itself was intentionally modified to exceed regulated contaminant levels…
Its true that this study says this. However, its likely that the parameters of the risk assessment are unreflective of the #biosolids application rates used in 🇬🇧 #agriculture & likely to substantially overstate the level of risk. In fairness, this requires a level of expertise to unpick…
March 22, 2025 at 12:56 PM
Its true that this study says this. However, its likely that the parameters of the risk assessment are unreflective of the #biosolids application rates used in 🇬🇧 #agriculture & likely to substantially overstate the level of risk. In fairness, this requires a level of expertise to unpick…
I don’t know who ‘we’ refers to but the idea that this is some kind of dodgy secret is misleading. The treatment of trade effluent arriving by sewer is regulated under the Water Industry Act. The treatment of commercial waste arriving by tanker is a fully permitted activity…
March 22, 2025 at 12:56 PM
I don’t know who ‘we’ refers to but the idea that this is some kind of dodgy secret is misleading. The treatment of trade effluent arriving by sewer is regulated under the Water Industry Act. The treatment of commercial waste arriving by tanker is a fully permitted activity…
This is claim is baseless. The transfer of commercial tankered waste and statutory requirements on all involved is covered under Duty of Care regulations and is a fully permitted activity…
March 22, 2025 at 12:56 PM
This is claim is baseless. The transfer of commercial tankered waste and statutory requirements on all involved is covered under Duty of Care regulations and is a fully permitted activity…
This claim isn’t evidenced but is almost certainly untrue. Official gov stats show that, on average, just 1.6% of British farmland recieves #biosolids each year www.gov.uk/government/s... …
March 22, 2025 at 12:56 PM
This claim isn’t evidenced but is almost certainly untrue. Official gov stats show that, on average, just 1.6% of British farmland recieves #biosolids each year www.gov.uk/government/s... …
This almost certainly isn’t a photo of #SewageSludge or #biosolids. #Biosolids in 🇬🇧 are almost exclusively applied as a solid known as ‘cake’ (tasty), not fired over fences using a rain gun…
March 22, 2025 at 12:56 PM
This almost certainly isn’t a photo of #SewageSludge or #biosolids. #Biosolids in 🇬🇧 are almost exclusively applied as a solid known as ‘cake’ (tasty), not fired over fences using a rain gun…
If we couple this fact to our knowledge that about only 1.6% of 🇬🇧 farmland recieves #biosolids per year, the alarmism begins to feel quite unjustified and frankly undermines the legitimate concerns over the possible risks of #biosolids use in #agriculture
March 21, 2025 at 11:57 AM
If we couple this fact to our knowledge that about only 1.6% of 🇬🇧 farmland recieves #biosolids per year, the alarmism begins to feel quite unjustified and frankly undermines the legitimate concerns over the possible risks of #biosolids use in #agriculture
The main issue is the assumed application rate. The ‘Smart form’ assumes app rates based on the regulated limits for metals in the #biosolids. But this isn’t what actually sets the legal app rate limit in practice. This is instead set by the Nitrogen (N) content of #biosolids…
March 21, 2025 at 11:57 AM
The main issue is the assumed application rate. The ‘Smart form’ assumes app rates based on the regulated limits for metals in the #biosolids. But this isn’t what actually sets the legal app rate limit in practice. This is instead set by the Nitrogen (N) content of #biosolids…
First, here is the section indicating that soil samples only need to be tested for metals every 20 years (true) and that, on this basis, annual applications over 20 years could impact the soil’s ability to support crop growth…
March 21, 2025 at 11:57 AM
First, here is the section indicating that soil samples only need to be tested for metals every 20 years (true) and that, on this basis, annual applications over 20 years could impact the soil’s ability to support crop growth…
The government research cited here indeed suggests possible issues with the support of crop growth resulting from ‘pollutants’ in #biosolids. However, the research outcomes in this instance are basically nonsense and here’s why…
March 21, 2025 at 11:57 AM
The government research cited here indeed suggests possible issues with the support of crop growth resulting from ‘pollutants’ in #biosolids. However, the research outcomes in this instance are basically nonsense and here’s why…
For #biosolids use in #agriculture, this is the key table. Its a bit complicated as first glance, & read-across to the 🇬🇧 context is tricky. However, only ‘restricted use’ would likely apply in 🇬🇧 as we have restricted application rates.
March 6, 2025 at 1:18 PM
For #biosolids use in #agriculture, this is the key table. Its a bit complicated as first glance, & read-across to the 🇬🇧 context is tricky. However, only ‘restricted use’ would likely apply in 🇬🇧 as we have restricted application rates.
Unsure how this story has developed as its behind a paywall. But from the data I’ve seen, the profile of #PFAS chemicals found in the water & soil isn’t well aligned to the #biosolids in question peer.org/wp-content/u...
February 15, 2025 at 10:08 AM
Unsure how this story has developed as its behind a paywall. But from the data I’ve seen, the profile of #PFAS chemicals found in the water & soil isn’t well aligned to the #biosolids in question peer.org/wp-content/u...
Self correction - in fact just 1.1% of 🇬🇧 farmland sown in 2023 recieved #biosolids. Hardly vast swathes.
January 17, 2025 at 11:36 AM
Self correction - in fact just 1.1% of 🇬🇧 farmland sown in 2023 recieved #biosolids. Hardly vast swathes.
Official 🇬🇧 stats show that #biosolids make up just 3% of all organic materials spread on farmland. The vast majority is slurry and Farmyard Manure from cattle.
January 17, 2025 at 11:36 AM
Official 🇬🇧 stats show that #biosolids make up just 3% of all organic materials spread on farmland. The vast majority is slurry and Farmyard Manure from cattle.
“the agency does not know where the sludge is spread. “It’s completely invisible to us,” said the insider.”
This is false. Water co’s stockpile #biosolids on fields to be spread by registering an S3 exemption. This includes grid refs for each and every stockpile.
www.gov.uk/guidance/reg...
This is false. Water co’s stockpile #biosolids on fields to be spread by registering an S3 exemption. This includes grid refs for each and every stockpile.
www.gov.uk/guidance/reg...
January 16, 2025 at 6:49 PM
“the agency does not know where the sludge is spread. “It’s completely invisible to us,” said the insider.”
This is false. Water co’s stockpile #biosolids on fields to be spread by registering an S3 exemption. This includes grid refs for each and every stockpile.
www.gov.uk/guidance/reg...
This is false. Water co’s stockpile #biosolids on fields to be spread by registering an S3 exemption. This includes grid refs for each and every stockpile.
www.gov.uk/guidance/reg...
The problem is #PFAS is ubiquitous. So high concentrations entering sewers can arise from landfill leachate & other industrial effluents but research shows #PFAS also arises from domestic sources ukwir.org/the-national...
January 16, 2025 at 5:57 PM
The problem is #PFAS is ubiquitous. So high concentrations entering sewers can arise from landfill leachate & other industrial effluents but research shows #PFAS also arises from domestic sources ukwir.org/the-national...
IMHO the issue with crossing this acceptability threshold is that it appears to be binary, at least at a glance. This makes it a challenge to understand, contextualise or communicate the releative risks.
January 14, 2025 at 8:53 PM
IMHO the issue with crossing this acceptability threshold is that it appears to be binary, at least at a glance. This makes it a challenge to understand, contextualise or communicate the releative risks.
Language is crucial here. Peer review resulted in swapping the term “significant human risk” with “exceeds acceptable risk level”. This is critical in the context of the EPA’s maximum acceptable risk level for #PFOA in drinking water, 4 ppt…
January 14, 2025 at 8:46 PM
Language is crucial here. Peer review resulted in swapping the term “significant human risk” with “exceeds acceptable risk level”. This is critical in the context of the EPA’s maximum acceptable risk level for #PFOA in drinking water, 4 ppt…
For reference, based on the limited #PFAS data currently available for 🇬🇧 #biosolids from CIP3, most would fall within tiers 1 and 2
December 27, 2024 at 5:02 PM
For reference, based on the limited #PFAS data currently available for 🇬🇧 #biosolids from CIP3, most would fall within tiers 1 and 2
December 17, 2024 at 6:58 AM
December 15, 2024 at 8:08 AM
Goodies picked up at this year’s #Biosolids & #Bioresources conference. Dried #SewageSludge (left) is fed to #Pyrolysis treatment to make #Biochar (right). Just one possible future avenue for 🇬🇧 #Biosolids
November 29, 2024 at 7:30 PM
Goodies picked up at this year’s #Biosolids & #Bioresources conference. Dried #SewageSludge (left) is fed to #Pyrolysis treatment to make #Biochar (right). Just one possible future avenue for 🇬🇧 #Biosolids
Empty #biosolids cake pad, Feb 2018. 3 conveyers that deposit dewatered #biosolids cake from the centrifuges can be seen at the back of the pad. The Thermal Hydrolysis Process #THP that facilitates Advanced Anaerobic Digestion #AAD #Sludge treatment can be seen behind the pad.
November 28, 2024 at 2:37 PM
Empty #biosolids cake pad, Feb 2018. 3 conveyers that deposit dewatered #biosolids cake from the centrifuges can be seen at the back of the pad. The Thermal Hydrolysis Process #THP that facilitates Advanced Anaerobic Digestion #AAD #Sludge treatment can be seen behind the pad.