Composting with hot box method (Howard-Higgins system)


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  • richard higgins
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Re: HH -2

Dear Christoph

I have found another entry you made with questions:

as you concluded your trials in Uganda, could you post the results? I would be especially interested in systematic data about the helminth eggs removal, do you have before - after combined with temperature?
Thanks in advance.


There were no results posted from the Uganda trials unfortunately.

(note by editor (EvM): see also related discussion about these trials in Kampala where the hot-box composting method was investigated: )

Normal pathogen testing is done from a sample taken to a micro biological laboratory as I have done all my previous pathogen testing.
There was no such print out from the Uganda trials from the laboratory at Makerere University.

All I was emailed was that there were no pathogens found according to the the standards I have enclosed before.

This is completely acceptable in the United Kingdom. If it is not acceptable in your country? Please tell what the standards are there.

We are working with a top agricultural college here in the |UK to do further trials for PhD reviewed articles.
This we have not done yet, so if this is your interest, please bear with us.

best regards

Richard Higgins.
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  • richard higgins
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Re: pathogen testing

We have always tested for pathogens according to the ABP regs/2011 of the European Commission
If there are other lists, for instance Uganda, please let me know where these can be found.

We did not specifically test for Ascaris eggs, but from this table you will see that these are destroyed at the temperatures described.

In our next test we will include other organisms that you can tell us about that are considered harmful pathogens to humans.

(note by editor (EvM): the embedded table was messed up, so I have converted it to a pdf file:)

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{Jenkins cites as his source: Feachem, et al. (1980) *Appropriate Technology for Water Supply and Sanitation*, The World Bank, Director of Information and Public Affairs, 1818 H St., Washington D.C. 20433. His chapter "Worms and Disease" also cites a number of other recent scientific studies on pathogen survival listing other bacteria, etc.}

How we have conducted these pathogen tests before is like this:

You take a cross section sample from 5 points in the sample and send it to the nearest lab for pathogen testing. They test for harmful pathogens for human health. These are the ones that are all included in the previous tables I have posted on the forum.

It is not that you ask the laboratory to test for this one or that one. This would probably be far more expensive.

That is why I have asked anyone if there is a different list that may apply to Uganda. If there is we will test at the micro biological laboratory there for the list of pathogens that applies to that country.

I hope this makes things clear.



P.S. If they want peer reviewed articles approving my system they are going to have to wait. I am trying to get an institution to carry this out.
I did ask Arno once, if all answers on this forum have to be scientifically proven.
there was no answer to this question.

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  • joeturner
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Re: Fw: re composting

richard higgins wrote:
As far as we know so far, the World health Organisation take their guidance (or some of it) from the European Directive on destruction of harmful pathogens contained in the Animal by Products Regulations 142/2011, in regard to destruction of human pathogens contained in human effluent. This was conveyed to me by the research establishment in Swindon WRC in the UK that holds and compiles such relevant information.

If the level of pathogen destruction is acceptable by the UK and the USA why would it not be acceptable in Uganda? Are there any other standards for pathogen control in Uganda?

Utter rubbish. The WHO calculated their standard from a Monte Carlo Quantative Microbial Risk Assessment proceedure.

It is obvious that an acceptable pathogen reduction standard in the UK/Europe is irrelevant in other places where the pathogen load is much higher.

The WHO guideline standard for exreta use in agriculture is <1 helminth ova per g, <1000 E.coli per g - WHO 2006 Table 4.2 page 63 .

>and where a 3log10 reduction may not reduce >pathogens to safe levels as defined by >the WHO standard.

Please send me the document this definition comes from. I would love to see it.

See above. And please explain why you are not aware of this.

Also why would the pathogen loading be much higher outside the EU?
Human waste is human waste and for instance in the book by Joe Jenkins (Humanure) The world acclaimed accepted system for human waste disposal (by many) he makes no such distinctions.

Really? You are seriously asking why pathogen loadings are higher in places where there is more infection?

The levels of maintained temperatures of the destruction of Ascaris eggs is met easily by the Howard-Higgins System. That is why I say Ascaris eggs - no problem - More is the problem, I understand, that in South Africa, perticularly Durban, they have stored human effluent for 40 years and Ascaris eggs are apparently found breeding again at different times. Well my answer to that is treat it properly, through controlled temperature treatment and don't store it! Use it!
The temperature requirements acceptable for the WHO I believe is, in the destruction of pathogens, 50 degrees C for one week.

Here is a table on destruction of ascaris eggs:
Roundworm (Ascaris) eggs applied directly to soil Several years
unheated anaerobic digestion Many months
composting toilets Survive well
thermophilic composting Killed in 2 hrs at 55 degrees C or 20 hrs at 50 degrees C or 200 hrs at 45 degrees C

This is taken from European Commission:
see table 2.1 below

European Commission DG Environment
WRc Ref: CO 5026/1 / 12787-0
September 2001

Table 2.1 Pathogenic micro-organisms that may be found in sludge derived from
faecal material
Bacteria Protozoa
Salmonella spp. Entamoeba histolytica
Shigella spp. Giardia lambia
Escherichia coli (enteropathogenic strains) Toxoplasma gondii
Pseudomonas aeruginosa Sarcocystis
Yersinia enterolitica
Clostridium perfringens
Clostridium botulinum Helminths
Bacillus anthracis Taenia saginata
Listeria monocytogenes Taenia solium
Vibrio cholera Diphyllobothrium latum
Mycobacterium spp. Echinococcus gramulosus
Leptospira spp. Ascaris lumbricoides
Campylobacter spp. Ancylostoma duodenale
Staphylococcus Toxocara canis
Streptococcus Toxocara cati
Trichuris trichura
Poliovirus Yeast
Coxsackievirus Candida albicans
Echovirus Candida krusi
‘New’ enterovirus Candida tropicalis
Adenovirus Candida guillermondii
Reovirus Cryptococcus neoformans
Hepatitis A-virus Trichosporon
Astrovirus Fungi
Calicivirus Aspergillus spp.
Coronavirus Aspergillus fumigatus
Norwalk-like calicivirus Phialophora richardsii
Small round viruses Geotrichum candidum
Parvovirus Trichophton spp.
Adenoassociated viruses
Influenza virus
Epidermophyton spp.

3.1 Heat
3.1.1 Thermophilic temperatures
Pathogens are inactivated during exposure to heat, which to be effective and relatively rapid
must be above their optimum growth temperature. The period of exposure is dependent on
the temperature and on the species of the organism. Feacham et al. (1983) determined the
thermal death curve of a number of enteric pathogens. These have been collated into a single
graph by Strauch (1991 and 1998), which indicates a ‘safety zone’ where, if the operating
parameters were above the minimum requirements, the resultant sludge would be virtually
pathogen-free (Figure 3.1).
These data suggest that the operating parameters should be in excess of 7 minutes at 70°C;
30 minutes at 65°C; 2 hours at 60°C; 15 hours at 55°C or 3 days at 50°C.
A recent review for UK government departments of reported practical studies, much of which
were carried out as part of the COST 681 programme in the 1980’s, concluded that 70°C for
30 minutes or 55°C for 4 hours would produce a sludge that is virtually pathogen-free
(Carrington et al., 1998).
The differences in the suggested exposure times arise from differences in the design of the
two studies. The data of Strauch was based studies using pure cultures of the microorganisms, whereas the studies reported by Carrington allowed sufficient time to ensure the
efficient warming of the sludge and also took into account the movement of the sludge through
a continuous flow system. The UK workers thought that 30 minutes was the minimum
residence time that would ensure that all sludge had been exposed to lethal time-temperature

Hard to know where to start here, given I was working on some of these original trials. None of them involved believing that the whole windrow was sanitised in 30 mins/4 hours because we understood that the majority of the heap would never get to that temperature. Hence the need for turning. The truth is that you are misapplying a European standard, which is of no relevance anyway to a developing country.

Professor Reed, of WEDC Water Engineering and Development Centre happens to be a world authority on such things. WEDC advise NGO's of appropriate technology.

Of course we would like our HH tecnology included in their books and papers, But it in lieu of funding at this present moment to publish a PhD peer reviewed paper in a medical journal, we have to continue as we are. But all temperatures shown in any papers I have found say that these harmful organisms are all destroyed at much lower temperatures than the HH -2 thermophilic system employs.

Yeah. And that for this discussion is irrelevant, given that Professor Reed is not able to tell the pathogen loading of your compost by eyesight. I am very happy to have a conversation with him, but having had conversations with many academics and workers in sludge composting over the years, I'm confident that nobody anywhere would make the outrageous claim that their compost was fully sanitised within 14 days.

Yes we believe we have, although at the turning out stage 14 days contents will be pathogen free. We analyze at 30 days due to the second heat increase in the system.

Cholera, the destruction for this organism is listed in the Humanure Handbook by Joe Jenkins.

I rest my case. You've not actually measured any pathogens at all have you?
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  • joeturner
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Re: Composting with hot box method (Howard-Higgins system)

richard higgins wrote:
P.S. If they want peer reviewed articles approving my system they are going to have to wait. I am trying to get an institution to carry this out.
I did ask Arno once, if all answers on this forum have to be scientifically proven.
there was no answer to this question.

If you are making extreme claims, you need some pretty good evidence. Some of us actually care about the truth.
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  • MGuenard
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Re: Fw: re composting

Dear all
Just entering your discusssion.

I have read this scientific study on Thermophilic composting - a hygienization method of source-separated faecal toilet waste

This may help!
Biotechnologies for household sanitation
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