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From: Oz <>
Subject: Re: IFST condemns UK Government's reported rejection of E.coli safety 
Date: Tue, 25 Mar 1997 09:12:39 +0000

In article <>, William R Hite
<> writes

>We do not need to go to Africa to use human sewage for agricultural
>purposes - the UK uses quite enough. I have no objection to its use as
>such - merely the slurry^H^H on parts foreign :-)
>Of course sewage sludge is not the same as raw human sewage, but clearly, from
>restrictions on its use it cannot be entirely free of nasty things. Further, the
>regulations do also state that untreated raw human sewage may be used.
>How well is all this policed?

Hmmm, well I use about 2,000,000 gallons a year.

>Sewage Sludge
>        These regulations say, inter alia, and as best as I could note
>        them from a conversation with an EA official:
>            -there are limits on heavy metal concentrations in the
>            soil

Correct, although this is not a problem these days as contaminated
sewage costs (the producer) so much they decontaminate before discharge
to the sewer. In fact given the low trace element status of my farm, I
wish the levels in sludge were higher. Particularly copper and zinc,
although I could do without the lead, chromium and cadmium. Regular soil
tests ensure the maximum levels are not exceeded. Currently I am good
for the next few hundred years unless sludge levels change.

>            -no livestock to graze on such land for 3 weeks after
>             application

Correct. This is exceeded, usually by several weeks.

>            -no fruit or vegetables normally eaten raw or grown in
>             direct contact with the soil shall be harvested within 10
>             months of application

The somewhat variable quality would (except for 'organic' produce) make
it far from ideal for vegetable growers to use. The crop losses alone
due to it's variable fertiliser content would be horrendously expensive
in a conventional system.

>         They further state that:
>            -untreated sludge, i.e. raw human waste, can only be used
>             if injected into the soil or, if spread on the surface,
>             must be worked into the soil as soon as practicable
>            -once worked in the same limits as for treated
>             sludge, above, apply

Dunno, never use untreated, never will, wouldn't want to.
It's not available locally anyway.

Agronomically the use of sewage sludge is very difficult. The product is
highly variable (even from load to load) and the traffic that is
required causes damage (sometimes severe) to the soil, although
irrigation is possible it's use is not popular with the operatives. (!)

The variability means that it's use is significantly restricted since
the level of nitrogen used on crops, and the timing, is typically highly
critical. For organic produce that rarely has anywhere near the optimum
nitrogen applied it could presumably be used all year. Winter
(irrigated) and summer use on grassland is ideal since grass has a
nitrogen response that typically is straight line up to close to
1000kgN/Ha but applications rarely exceed 500kgN/Ha and so the nitrogen
is useful, and the phosphate (from phosphatic water softeners) is
appreciated. The most effective use is on grass for conservation where
the 3 week grazing restriction is easily significantly exceeded. For
cropping the only really useful crop is oilseed rape, that does not
respond as badly as most crops to exceeding the optimal N rate and where
the timing of the N is rather uncritical. A reduced (say half) rate
application in summer which is then ploughed in is quite useful for
winter rape. Spring oilseed rape is a minority crop (the yields are very
low) but the window for application is very wide, probably from
September to March, and the low yield means that missapplication has
limited effect (you lose money either way).

The water board I use (Thames) get highly agitated at the merest hint of
a thought that the regulations are not explicitly followed and
preferably exceeded and one has to sign an agreement stating that you
will obey the regulations. They do check up and will refuse to supply in
future if they are not followed, indeed I wouldn't be surprised if they

Note that treated waste is the sludge formed by standing the treated
waste in large tanks. The supernatant liquid is returned to the
watercourse and complies with the very strict regulations that this
requires. I doubt that the sludge is a hazard even when it is fresh and
before it has had a week standing in the works and three+ weeks exposed
to the sunlight.

I don't think you can compare a well regulated and monitored plant in
the first world where spares and expertise are permanently on line with
a third world 'plant' in a country where (probably not through any fault
of theirs) repairs and many spares take quite a while to deal with.

Also note that (see promed) pathogens in UNtreated sewage are in fact
very low. The figures that were given there were a few pathogenic
bacteria per liter, indeed so low as to be difficult to measure. I find
this surprising, but still. Whether this is also the case in the third
world I do not know.

'Oz     "Is it better to seem ignorant and learn,
         - or seem wise and stay ignorant?"

From: Oz <>
Newsgroups: misc.survivalism,misc.rural,sci.agriculture
Subject: Re: Pesticide Problems
Date: Wed, 18 Mar 1998 07:05:51 +0000

In article <>, Tracy Aquilla
>In Article <>, John March
>>Tracy Aquilla wrote:
>>>But this has not made the headlines because the activists are
>>> so busy chasing red herrings like sludge and food irradiation.
>>I'm not sure that sludge is such a red herring.
>Well, we can recycle it back to the land, or just keep on putting it in the
>water. I happen to think the former is more sustainable.

Like everything there's sludge and sludge. In the UK, and I guess
elsewhere, sewage sludge is a byproduct of activated sludge sewage
digestion plants. This is a bacterial fermentation and as such is rather
easily poisoned by heavy metals. As a consequence it cannot be used for
significantly contaminated sewages.

In the UK such sewages were dumped at sea but with very high charges for
discharging heavy metals to sewage plants in recent decades the amount
of seriously HM contaminated sewages has dropped precipitously and now
constitutes a very low level (it may even be effectively zero).

The main contaminants of concern are cadmium, mercury and lead (chromium
seems to be less of a problem these days) but even so the levels are so
low as to allow decades of use except on soils that are already
naturally very high. Zinc and copper are also present but since most
soils are deficient these might well be considered as fertiliser and a

As far as sustainability is concerned it is essential that sewage sludge
is returned to the soil. Most of the phosphorus that leaves farms as
food for human consumption is trapped in the sludge and recycling it is
absolutely essential for any even half serious effort at sustainability.
It also contains significant amounts of nitrogen, but the digestion
process is designed to reduce most of that to free nitrogen and thus
lose it from a sustainability viewpoint. Most of the potassium is lost
in the sewage outfall water, I would guess that much less than 10%
(probably only a few %) of K is recycleable.

The bacterial problem is really not a problem. Applied to the land for
ploughing in, or to grassland three weeks (IIRC) before grazing or grass
conservation the already utterly minute pathogenic loading is
deactivated by soil (ploughing) and/or sunlight (surface treatment).
Compared to animals dunging on the pasture, or liberal applications of
slurry or manure, both of which have gone on for centuries, the
bacterial loading in utterly unimportant.

I worked on a farm that used 12,000,000 gallons/year (a mostly vegetable
farm), and we generally use 2,000,000 gals. The product is typically 2%


From: Oz <>
Newsgroups: misc.survivalism,misc.rural,sci.agriculture
Subject: Re: Pesticide Problems
Date: Wed, 18 Mar 1998 08:13:18 +0000

In article <>, John March <ati-> writes

>While it can be argued that pre-application analysis can prevent sludge
>of sub-standard quality from being used,

Sludges from any individual plant are drawn from a fixed area and do not
vary very significantly from load to load other than in solids content.

>this analysis, if done for the
>wide range of contaminants that make it down people's toilets, can be
>altogether cost prohibative.

Simply untrue. Even the sludge from the relatively small works that I
draw from has every tank analysed and the amounts of nutrients and heavy
metals applied are sent to me. On top of that soil analyses for major
nutrients and heavy metals are (by law) taken periodically (every two or
three years) to ensure that nothing adverse has occurred. I am sent
these as well.

>Given the level of uncertainty that
>can be associated with waste water treatment,

These are not significant at all.

>it seems unlikely that
>sludge application should be considered a "best practice" option for
>long term farm management.

Why? It provides a public service, it is ecologically highly beneficial,
it is an excellent means of improving sustainability and it is entirely
the natural place for treated human excreta to be placed for recycling.

The alternative means of disposal are expensive, ecologically highly
damaging and go completely against the current wish for recycling and
sustainability. I can see nothing but severe disadvantages and I am
quite astonished that anyone should suggest alternative disposal


From: Oz <>
Newsgroups: misc.survivalism,misc.rural,sci.agriculture
Subject: Re: Pesticide Problems
Date: Wed, 18 Mar 1998 19:13:04 +0000

In article <>, John March <ati-> writes

>Are there analysis performed for VOC's? Industrial solvents?

Not so far as I know. I can check. Which did you have in mind in

>Not as far as you've seen, but are there any documented instances
>of high sodium levels in sludge damaging crops?

I am not aware of any. Actually sodium is quoted, but I wish ours had a
LOT more, it improves the palatability of grass. I would only expect
this to be a problem in coastal areas during storms. I am very inland.

>Relax, Oz.  I stand corrected.  Clearly sewage sludge application
>represents a good option for your situation.  But that doesn't give
>it a green light all the time.  In the area I work I send, on occassion,
>up to 250,000 gallons of waste water to the treatment plant
>(batch load) laden with high concentrations of TCE, MEK, Toluene and
>some other pretty significant organic chemicals.

Well, you ought to be paying (on the UK system) truly HUGE disposal
costs. In fact I am pretty sure that heavily polluted waste water gives
the sewage companies the *right* to refuse to accept your connection and
force you to treat it all as toxic waste. A right, from what I have
heard, that they are delighted to exercise at every opportunity (see
below), hence the very significant clean up of our sewage system in
industrial areas.

>The load is called in
>before sending so the plant can prepare itself.  On the week I send that
>load, the resultant sludge _may_ not be suitable for farming with.
>In this case, it would be unwise for a farmer to be dependant on sludge
>from the receiving plant that week.  Sludge from here would be better
>considered an occassional additive rather than a regular amendment.
>I'm sure there are other instances such as this elsewhere.

Seems to me that the US allows it's industry rather more latitude than
other countries. Your description sounds more like a third world
situation. Bearing in mind that sludge is only about 2% of the total
received, and the rest goes into the river (purified) under very
exacting cleanliness criteria, I would think the National River
Authority would have come down on your sewage works like a ton of
bricks. Nothing like removing permission to discharge treated water into
a river to give a sewage works very severe constipation indeed.


From: Oz <>
Newsgroups: misc.survivalism,misc.rural,sci.agriculture
Subject: Re: Pesticide Problems
Date: Wed, 18 Mar 1998 19:59:50 +0000

In article <6ep76p$924$>, Adriana C. Bruggeman
<> writes

>Then what's happening to those HM contaminated sludges, which were
>previously discharged to the sewage plants (and subsequently dumped
>at sea at high cost for the discharger - if I understood you right)?

You haven't quite got it right. Due to the high charges it paid firms
that previously discharged their waste to keep it separate. Some then
paid for it to be treated as toxic waste but this too is horrendously
expensive. Most found that heavy metal waste was in fact quite valuable
and then sold it to processors for turning back into copper, lead,
chromium etc.

For example wettable copper oxychloride is made by blowing air through
the waste solution from printed circuitboard manufacture. I am not sure
if there are any pre-processing stages, but probably not.

Of course the demise of much heavy industry helped.

The net result was a huge reduction in toxic materials discharged to
sewers. OK, probably not yet perfect, I expect there are still some
sludges that have to be put in landfill, but certainly very much better
than it was.


From: Oz <>
Newsgroups: misc.survivalism,misc.rural,sci.agriculture
Subject: Re: Pesticide Problems
Date: Fri, 20 Mar 1998 06:37:27 +0000

In article <>, March <> writes

>The load is landfill leachate.  It is rarely the same thing twice,
>but concentrations of organics can be in the 200 to 1200 ppb range,
>depending on a variety of factors such as waste age, placement,
>and of course, waste stream concentrations and precipitation.

Not disagreeing. What is allowed in a landfill site depends on the site
in the UK. Some are porous, and tipping type is restricted, others are
not and are much less restricted. Not something I know much about.

>I imagine the concentrations of the more accesible molecules
>(from an energy standpoint) are greatly reduced by the waste
>water treatment process, but my concern with sludge application
>is for the more persistent organics, such as TCE.

What is TCE?

>Have there
>been studies done on the effects of these on crops?  Would corn,
>for example, translocate TCE from the sludge to the shoots (if
>corn could tolerate TCE at all)?

I have had a chat with the water board who supplies my sludge. What I
said was correct vis:

1) All industrial sites are inspected. The frequency of inspection
varies considerably. For those that, on inspection, have a couple of
toilets and washbasin and have no toxic products on site it may be once
every few years. For those with toxic products it could be every month
or even weekly. Samples of outflow are taken at random times without
appointment for anlaysis, particularly if they have surcharges for high
BOD or traces of toxic products in their outflow. Sewage plant inflow,
sludge and outflow are tested weekly.

2) There is a level of HM that permits the water board to refuse to
accept the outflow. My contact is getting details, but he considers the
levels quite small and they refuse to accept the outflow if it is ever
breached. The digestors are very sensitive to HM.

3) Samples of sludge and outflow water from the sewage plant are sampled
very regulary by the water boards. They are, on a plant with no record
of failure, sampled randomly by the Environment Agency (an independent
govt authority) about 12 times a year. My contact is finding the tests
performed, but he is very confident that the analysis is very thorough.

Personally I suspect it's along the gas chromatograph lines. The water
board may not test for toxic organics, but I will know sometime next
week. We both think it is vanishingly unlikely that the Environment
Agency do not test for organics of all sorts, however. Since the
'allowable levels' of organics in outfall water are likely to be very
tiny indeed (the water is drunk several times along the length of the
river) it's hard to see why the sludge should be at anywhere near levels
that should give concern.

I will report back midlle of next week when I have had a chance to speak
to their tech people.


From: Oz <>
Newsgroups: sci.agriculture
Subject: Re: we are not alone
Date: Tue, 24 Mar 1998 09:32:26 +0000

In article <>, John March <ati-> writes
>Oz wrote:
>> It's
>> completely pointless spending much money reducing 3%
>Can you give a reference for 3%?

Craig Severson said (up the thread a bit)

I believe this report was put out by either a Senator
or a Representative from Iowa. The important thing to
remember about this report was that it dealt with
pollution from private sources and not public sources.

If we are talking about the same report it specifically
mentioned that during some torrential rainfalls during
1995 or 1996 in North Carolina 23 lagoons on large
confinement hog operations failed. These lagoon failures
led to pollution of streams and some fish kills. These
lagoons represented about 3% of the waste from hogs in
the state at that time. Also when planning lagoons the
planners typically figure 1 and 1/2 gallons of waste per
day plus there are many more people than pigs in N. Carolina.

What was failed to be mentioned was that during that
same period of time 206 municipal waste lagoons failed
also polluting streams and groundwater. These lagoons
represent 94% of N. Carolinas municipal waste systems
plus to put it into perspective municipal planners normally
calculate 140-160 gallons per person per day. In an EPA
report released in 1997 the EPA specifically mentioned that
pollution from city waste treatment plants indeed caused
pollution hundreds of times greater than did those of the
hog farms.

End Craig Severson

I misinterpreted exactly what he said. On re-reading it would appear
that the sewage pollution was in fact very much greater than 97% in this

>> of the pollution by
>> 50%, you only go from 100% to 98.5%. OTOH reducing 97% of the pollution
>> by 50% takes you from 100% down to 53%. This is not a reason NOT to
>> encourage a reduction in all pollution, but placing the blame on the 3%
>> whilst ignoring
>Why would you chose to _ignore_ the other 97%?

Because you are busy blaming it on farmers. This is *actually* what
happend in the UK for many decades. It was only when the WaterBoards
were privatised, and the National Rivers Authority (now the Environment
Agency) became independent (although still a govt body) that the full
extent of sewage pollution started to be appreciated.

I have an actual example not 1/2 mile from me that happened four years
ago. Due to a collapse of pitch-fibre sewer pipe untreated sewage rose
out of the road and flowed into a local ditch. This continued for two
*months*. Assorted pumps and pipes to bridge the break failed literally
on a daily basis. Now, had a farmer put a fraction of that amount of
untreated animal waste into the same ditch he would have been sued, the
EA would have entered his land and pumped the ditch dry and charged him
ALL the costs, plus a daily fine plus whatever the courts added for
breaking the law. Action only occurred when an official complaint from
the local council was sent direct to head office of the EA in London. I
have seen NO press reports as to any fines being levied.

>> >Now if we're talking about global
>> >pollution, in the abstract, wast water treatment plants play a leading
>> >role in the discussion, and are as much agriculture's concern as anyone
>> >else's.  But when a city dweller raises concern over events like those
>> >in NC, agriculture should realize that their worries are real and
>> >justified.  Rather than jump to a defensive position, farmers _and_
>> >researchers should try, and I know its not easy, to explain what went
>> >wrong in detail, and whats being done to prevent it from happening
>> >again.
>> Exactly what I would say but exchanging 'human-generated' pollution for
>> 'agricultural'. With rather more validity too in this case.
>...with agriculture falling under 'nonhuman-generated'?  C'mon Oz,
>how much of the 'human-generated' pollution do you think can be
>subdivided into industries much smaller than agriculture,

Sewage works.
Heavy metal contaimination of all kinds (none agricultural).
Solvents and other waste hydrocarbons.

>all of whom
>would say 'everyone else but me'.  If each of those industries looked
>to themselves first, the 50% of 97% number you're looking for might
>be possible.

Yes. My point exactly. However the anti-ag eco activists seem to be
easily induced to attack farming leaving all the other sources
untouched. I bet those industries cannot believe their luck. There is,
of course, rather an easy way to seriously reduce all these sources.

1) Set sensible safe levels for HM and other non-biodegradeable
contaminants for sewage sludge applied to the land as fertiliser.

2) Prohibit dumping of sewage sludge (ie all sewage) at sea. Charge full
landfill charges for sludge dumped in landfill and ensure proper
emission controls for sludge incinerators.

3) Pass laws allowing the Waste Treatment Providers (WTP's) to enter
properties connected to their sewage plants without warning to take
samples and inspect. Also allow WTP the right to refuse to accept
effluent above certain reasonable (for producing agriculturally safe
treated sludge) levels.

4) WTP's can charge a premium for contaminants between the levels above.

5) I assume that the US already has laws prohibiting the random dumping
of toxic waste, which is what the items in (3) above really are.

Judging from the UK experience the very high charges (or refusal) that
WTP's make for contaminated waste results in segregation and recycling
of most toxic wastes. The sludge is useable for agriculture, thus
completing the ecological cycle. The amount of toxic waste in landfill
is significantly reduced, as is the need for disposal of contaminated
sewage sludges and usually the recycling element for firms that produce
toxic waste results in a net increase in profit. HM's and solvents have
a value, often quite a high value.

Note that it is in everyone's interest to reduce the amount of
contamination, both upstream from them and downstream, which is why it

>But if what you say above is true, agriculture is not even a remotely
>obvious source.  You make it sound as if agriculture has _all_ its waste
>under control, and anything that states otherwise is simply unfair and
>probably fabricated.

No, of course not. However most (all?) of the waste from agricultural
systems is biodegradeable and has been for several decades. This means
that in general pollution incidents are not permanent, indeed are often
very short lived indeed. There seems to be a problem with very low
levels of pesticides in water, IPU and atrazine for example, which
although IMHO not a health risk need attention where the contamination
is still continuing. The 'problem' with nitrates seems to become less
and less of a health risk with every new trial, largely confirming the
epidemiological work done decades ago.

None of this compares in severity with HM, solvents and other long lived
industrial chemical pollution which is often at very high levels, very
toxic and produces contamination that is essentially permanent.


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