Download milking water

Inlet and outlet structures,
piping and control valves
for 19000m3 biogas
reactor at Hilmar Cheese.
John Campbell, who
designed the reactor is
in the foreground.
Photo: John Campbell.
MILKING WATER
Writer John Spavin
In California’s Central Valley, where scorching summers
last nearly eight months, a New Zealander who learnt his
environmental engineering skills in Southland’s cool climate
has found his calling. His American employers backed his
innovative ideas to recycle and reclaim water and 11 years
later, they are still developing and inventing together.
November/December 2013
22
Below: Floating
membrane cover to
capture biogas from
the 19000m3 anaerobic
reactor. Photo: John
Campbell.
John Campbell’s skills and work range
from biological engineering, to waste
water treatment engineering to food
process engineering at the world’s largest
cheese factory where there is no rainfall:
not one drop, from March to November
and temperatures hover around 3540 degrees Celsius. Mr Campbell’s an
expert at reclaiming water and recycling
it after removing its pollutants to turn
them into biogas to power factories. His
process includes a series of biological and
physicochemical treatments followed by
ultra-filtration to remove tiny particulates
and bacteria.
The Hilmar Cheese company is
around a two-hour drive southeast of
San Francisco. It produces cheddar and
American cheeses for both retail and
wholesale markets at home and abroad.
Formed in the 1980s when some local
dairy farmers combined to maximise their
return on the rich milk yielded by their
Jersey herds, they set out to use science
and size to win markets.
More than 230 dairy farms supply six
million litres of milk daily to the factory.
It all emerges as cheese or whey protein
and lactose products. Producing its 1.1
million pounds (500,000 kilogrammes)
of cheese each day promotes Hilmar
to the largest dedicated cheese factory
anywhere.
It seems unusual that a water recycling
engineer could learn anything relevant
in Southland’s temperate climate that
might fit in an arid American valley but Mr
Campbell says it’s not where he learned
his skill that counts; it’s the combination of
his skills – and the fact that New Zealand
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“IF WE PULL 1.6 MILLION
GALLONS OF WATER
A DAY FROM WHEY,
THAT’S 1.6 MILLION
GALLONS OF WATER
THAT WE DON’T
NEED TO DRAW
FROM THE GROUND.”
engineers’ skills are honed by the need to
invent and innovate while working within
comparatively tiny budgets.
In the 1970s to early 1980s, Mr Campbell worked at Invermay’s MAFtech on a
project he says was unusual, and at the
Alliance Group in Southland. He bred
cultures of bacteria to generate biogas
from what would otherwise have been
pollutants that would have required large
amounts of energy to dispose of properly.
The pay-back doubled, in that sense – the
wastewater treatment produced energy,
and saved the energy that would otherwise have been required to clean it up.
Two politicians changed his life: Roger
Douglas and, eight years later, Simon
Upton. The reorganisations wrought by
both after MAFTech was dismembered
left Mr Campbell as Managing Director
in a management buyout of his unit at
Invermay. He spent up to six months
a year overseas chasing work of the
required scale. Eventually he saw
“overseas was where the opportunities
lay” and left.
Eleven years ago, he had the chance
to combine his skills to apply his water
recycling and energy production knowledge at Hilmar Cheese – and he hasn’t
looked back.
Water science is vital to the application
of successful food production on California’s dry soil. Irrigation water evaporates
quickly, leaving behind dissolved salts.
There is insufficient rainfall to flush the
salts from the soil and the resulting salinity
inhibits plant growth and kills crops if left
unchecked.
That’s a completely different set of
circumstance to ours in New Zealand,
even Canterbury in a dry year. Mr
Campbell works in a team reclaiming
every drop of water from Hilmar’s
production, waste and by-products.
Milk’s water content is around 87 per
cent. As Hilmar doesn’t bottle milk, the
team grabs back as much of the water
as it can. When cheese is produced, the
leftover whey yields proteins and sugars
that make food supplements and edible
lactose products.
The remaining liquid – in effect, diluted
milk – undergoes straining, equalization,
and dissolved air flotation. It sits in
anaerobic digestion reactors before
undergoing more filtration processes,
reverse-osmosis, evaporation and finally
deep well injection and storage of reuse
water for internal and agronomic reuse.
When all food processes have extracted
their bounty, reverse osmosis reclaims
most of the remaining liquid and recycles
up to 1.6 million gallons of usable water
Engineering Insight » Volume 14/6
Photo: John Campbell.
(4.56 million litres) daily to surrounding
farms. What remains is not waste, but
fuel – and Mr Campbell cooks up bacteria
in bio-reactor tanks. They eat the organic
solids and produce biogas to supply up
to eight per cent of the company’s natural
gas needs.
When Mr Campbell started out on
water reclamation in New Zealand, much
of the excess whey was used in nutrients
for farming. That practice had long gone
from Hilmar, even before he arrived
(although the whey was valuable as a
fertiliser substitute).
Dairy plants must be clean to avoid
contaminating the product. Caustics,
acids and detergents flushed through
tanks and pipes and then expelled with
wastewater can vary the pH from two
to 13 in seconds. The chemical oxygen
demand (COD), a measurement of the
amount of the oxygen required to oxidize
mainly organics in water, can swing
from 2,000 parts per million (ppm) to
200,000ppm in a few minutes. Somehow,
the recycler needs to smooth these peaks
to treat the water but the returns are
worth the effort.
“If we pull 1.6 million gallons of water
a day from whey, that’s 1.6 million gallons
of water that we don’t need to draw from
the ground,” Mr Campbell says. “It also
means that we haven’t got 1.6 million
gallons of reclaimed water to irrigate.”
Processing reclamation plant feedwater
organics to produce biogas operates on
the same principle as at Southland’s Alliance Freezing Works. The difference is the
Hilmar plant at 19,000 cubic metres (m3) is
four times larger.
“If the conventional activated sludge
technology was used, a hyper-massive
amount of electricity would be required
and the renewable biogas would not be
produced.”
Mr Campbell is culturing a fourth
19,000m3 biogas reactor in which he
brews his bacteria colonies. This is the
highlight of his work to date. He says it’s
“huge” and designed to handle the high
fat, high suspended solids in the likes
of dairy, wool scours, meat processing
and other food processing wastewaters.
This reactor is one that Mr Campbell has
developed under his own company’s
aegis rather than Hilmar’s.
Cultivating bacteria is slow and
methodical work that starts with
individual, free-swimming bacteria,
aggregating eventually into groups
www.cadconcepts.co.nz
November/December 2013
that measure up to three millimetres in
diameter. They may have reached 100,000
kilogrammes dry weight by the time
they’re ready to feast on the diluted milkfeed water. Three of his previous, similar
size reactors have run flawlessly for seven
years at a Hilmar site in Texas.
“Working with the company has just
been a blessing.” he says. “There are not
many companies around the world large
enough to try this out.”
After 11 years in California Mr Campbell
still misses friends and family back here
in New Zealand. “It’s really, really hard to
get a continuity of engineering research
in New Zealand. There’s no R&D [research
and development] breaks and no real tax
incentives.”
He meets each Thursday for “coffee”
with a bunch of Kiwi “ex-pats”. The
consensus of the reasons they left New
Zealand to pursue their careers haven’t
changed. “The US is swimming with
good engineers but Americans have a
fond regard for New Zealand scientists,
technologists and engineers.”
Mr Campbell wonders if, as Invermay,
his old research institute faces closure, the
next generation might soon be thinking of
packing their bags to follow his trail.
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Individual bacterial cells less than a
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The granules have very high settling
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of the other contaminants to renewable
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