Dream Farms

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9 Jun 2005 18:12:58 -0000

 

Dream Farms

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ISIS Press Release 09/06/05

 

Dream Farms ********

 

Abundantly productive farms with zero input and zero

emission powered by waste-gobbling bugs and human ingenuity

Sustainable development is possible Dr. Mae-Wan Ho

 

A fully referenced version of this paper is posted on ISIS

members' website.

http://www.i-sis.org.uk/full/DreamFarmFull.php

Details here

http://www.i-sis.org.uk/membership.php

 

Environmental engineer meets Chinese peasant farmers

 

Doesn't it sound like a dream to be able to produce a super-

abundance of food with no fertilizers or pesticides and with

little or no greenhouse gas emission? Not if you treat your

farm wastes properly to mine the rich nutrients that can

support the production of fish, crops livestock and more,

get biogas energy as by-product, and perhaps most

importantly, conserve and release pure potable water back to

the aquifers.

 

That is what Professor George Chan has spent years

perfecting; and he refers to it as the Integrated Food and

Waste Management System (IFWMS).

 

Chan was born in Mauritius and educated at Imperial College,

London University in the United Kingdom, specializing in

environmental engineering. He was appointed director of two

important US federal programmes of the US Environmental

Protection Agency and the US Department of Energy in the US

Commonweath of the Northern Mariana Islands of the North

Pacific. On his retirement, Chan spent 5 years in China

among the Chinese peasants, and confessed he learned just as

much there as he did in University.

 

What he learned was a system of farming and living that

inspired him and many others including Gunter Pauli, the

founder and director of the Zero Emissions Research

Initiative (ZERI) (www.zeri.org).

 

Chan left China in 1989, and continued to work with Gunter

and others in ZERI through consultancy services. This work

has taken him to nearly 80 countries and territories, and

contributed to evolving IFWMS into a compelling alternative

to conventional farming.

 

The integrated farm typically consists of crops, livestock

and fishponds. But the nutrients from farm wastes often

spill over into supporting extra production of algae,

chickens, earthworms, silkworms, mushrooms, and other

valuables that bring additional income and benefits for the

farmers and the local communities.

 

Treating wastes with respect

 

The secret is in treating wastes to minimize the loss of

valuable nutrients that are used as feed to generate further

nutrients from algae, fish, etc., that feed a variety of

crops and livestock. At the same time, greenhouse gases

emitted during the first phase of waste treatment are

harvested for use as fuel, while the oxygen required in the

second phase of waste treatment - which gets rid of toxins

and pollutants - is generated by photosynthetic algae, so

fish stocks are not suffocated through lack of dissolved

oxygen in the nutrient-rich water entering the ponds.

 

Livestock wastes are first digested anaerobically (in the

absence of air) to produce biogas (mainly methane). The

partially digested wastes are then treated aerobically (in

the presence of air) in shallow basins that support the

growth of green algae. By means of photosynthesis, the algae

produce all the oxygen needed to oxidise the wastes to make

them safe for fish. This increases the fertilizer and feed

value in the fishponds without robbing the fish of dissolved

oxygen. All the extra nutrients, therefore, go to improve

productivity. Biogas is used as a clean energy source for

cooking, and also enables farmers to process their produce

for preservation and added value, reducing spoilage and

increasing the overall benefits.

 

IFWMS has revolutionized conventional farming of livestock,

aquaculture, horticulture, agro-industry and allied

activities in some countries, especially in non-arid

tropical and subtropical regions. It has solved most of the

existing economic and ecological problems and provided the

means of production such as fuel, fertilizer and feed,

increasing productivity many-fold.

 

" It can turn all those existing disastrous farming systems,

especially in the poorest countries into economically viable

and ecologically balanced systems that not only alleviate

but eradicate poverty. " Chan says.

 

Increasing the recycling of nutrients for greater

productivity

 

The ancient practice of combining livestock and crop had

helped farmers almost all over the world. Livestock manure

is used as fertilizer, and crop residues are fed back to the

livestock.

 

Chan points out, however, that most of the manure, when

exposed to the atmosphere, lost up to half its nitrogen as

ammonia and nitrogen oxides, before they can be turned into

stable nitrate that plants use as fertilizer (see Box 1).

The more recent integration of fish with livestock and crop

has helped to reduce this loss.

 

The important addition of a second production cycle of

nutrients from fish wastes has enhanced the integration

process, and improved the livelihoods of many small farmers

considerably. But too much untreated wastes dumped directly

into the fishpond can rob the fish of oxygen, and end up

killing the fish.

 

Box 1 How volatile nitrogen is turned into nutrient for

plants Livestock manure contains large amounts of ammonia

gas that must be turned back into stable nitrate before it

can be absorbed as nutrient by plants. Nitrification is the

process in which soil bacteria oxidize ammonia (NH3)

sequentially into nitrite (NO2) and then nitrate (NO3).

Ammonia is oxidized into nitrite by bacteria belonging

mainly to the genus Nitrosomonas, but also Nitrosococcus,

Nitrosospira, Nitrosolobus and Nitrosovibrio. Nitrite is

then further oxidized into nitrate by bacteria belonging

mainly to the genus Nitrobacter, but also by bacteria in

other genera such as Nitrospina, Nitrococcus and Nitrospira.

 

 

In IFWMS, the anaerobically digested wastes from livestock

are treated aerobically before the nutrients are delivered

into the fishponds to fertilize the natural plankton that

feed the fish without depleting oxygen, thereby increasing

fish yield 3- to 4-fold, especially with the polyculture of

many kinds of compatible fish feeding at different levels as

practiced in China, Thailand, Vietnam, India and Bangladesh.

The fish produce their own wastes that are converted

naturally into nutrients for crops growing both on the water

surface and on dykes surrounding the ponds.

 

The most significant innovation of IFWMS is thus the two-

stage method of treating wastes; the anaerobic digester

followed by the shallow aerobic basins containing green

algae. Livestock waste contains very unstable organic matter

that decomposes fast, consuming a lot of oxygen. So for any

pond, the quantity of livestock wastes that can be added is

limited, as any excess will deplete the oxygen and affect

the fish population adversely, even killing them.

 

Chan is critical of " erratic proposals " of experts, both

local and foreign, to spread livestock wastes on land to let

them rot away and hope that the small amount of residual

nutrients left after tremendous losses that damage the

environment have taken place.

 

According to the US Environment Protection Agency, up to 70%

of nitrous oxide, N2O, a powerful greenhouse gas with a

global warming potential of 280 (i.e., 280 times that of

carbon dioxide) comes from conventional agriculture. Nitrous

oxide is formed as an intermediate in denitrification, a

process in which soil bacteria reduce nitrate ultimately

back to nitrogen gas. Denitrifying bacteria belong to two

main genera, Pseudomonas and Bacillus. Animal manure could

be responsible for nearly half of the N2O emission in

agriculture in Europe, according to some estimates; the

remainder coming from inorganic nitrate fertilizer. Thus,

anaerobic digestion not only prevents the loss of nutrients,

it could also substantially reduce greenhouse gas emissions

from agriculture.

 

Chan further dismisses the practice of composting nutrient-

rich livestock wastes, for this ends up with a low-quality

fertilizer that has lost ammonia and nitrite. Instead of

mixing livestock wastes with household garbage in the

compost, Chan recommends produce high-protein feeds such as

earthworms from the garbage, and using worm castings and

garbage residues as better soil conditioners. He is also

critical of the outmoded practice of putting manure in

septic tanks for not much financial or other benefits while

the badly treated effluent is just as dangerous as the waste

itself.

 

Instead, the livestock waste digested anaerobically followed

by oxidation in open shallow basins with natural algae

before letting the treated waste effluent flow into the fish

pond, can convert almost 100% of the organic nutrients into

inorganic nutrients that will not consume any oxygen to

deprive the fish. So, theoretically, the quantity of waste

input into the pond can increase 10-fold without the risk of

pollution. But, Chan cautions, the nutrients in the waste

must be totally used by both fish and crop culture, or the

nutrients can create problems of eutrophication – over-

enrichment of plankton - that uses up all the oxygen in the

pond, thereby lowering productivity.

 

To close the circle, livestock should be fed with crops and

processing residues, not wastes from restaurants and

abattoirs. Earthworms, silkworms, fungi, insects and other

organisms are also encouraged, as some of them produce high

value goods such as silk and mushrooms.

 

The digester can be as simple as a couple of concentric

plastic bags of 5m3 capacity or 200-litre drums for a small

farm, or a complex reinforced concrete steel structure with

an anaerobic sludge blanket to collect the biogas for a big

farm or industrial enterprise.

 

As the fresh wastes enter the digester, the waste-eating

bacteria transform the unstable ammonia (NH3) and nitrite

(NO2) into stable nitrate (NO3), which is ready for use as

fertilizer. As more wastes are added, the digester also

produces an abundant and inexhaustible supply of biogas -

2/3 methane (CH4) and 1/3 carbon dioxide (CO2) - a

convenient source of free and renewable energy for domestic,

farming and industrial uses (see Box 2). Big farms, meat and

fish-packing plants, distilleries, and various agro-

industries are now self-sufficient in energy, besides having

big volumes of nutrient-rich effluent for fertilizing

fishponds, and `fertigation' (fertilization and irrigation)

of many kinds of crops.

 

Box 2 Formation of biogas [9] Certain bacteria naturally

present in manure produce a combustible gas (biogas) when

they digest organic matter anaerobically (in the absence of

oxygen). Biogas typically contains between 60 and 70 percent

methane. Anaerobic digestion involves two groups of

bacteria. The first group of ordinary bacteria produces

organic acids such as acetic acid by fermentation. The

second group of bacteria, the methanogens (methane makers),

is special, it breaks down the organic acids and produces

methane as a by-product. Methanogens cannot tolerate oxygen

and are killed when exposed to oxygen. Instead, they can use

the dead end products of fermentation, carbon dioxide or

organic acids such as acetic acid, to generate methane: (see

http://www.isis.org.uk/DreamFarm.php for formulas)

 

Methanogens are found wherever oxygen is depleted, such as

wetland soils, aquatic sediments and in the digestive tracts

of animals. Methane formation is the final step in the decay

of organic matter when carbon dioxide and hydrogen

accumulate, and all oxygen and other electron acceptors are

used up.

 

 

Proliferating lifecycles for greater productivity

 

The aerobic treatment in the shallow basins depends on

oxygen produced by the green alga Chlorella. Chlorella is

very prolific and can be harvested as a high-protein feed

for chickens, ducks and geese.

 

When the effluent from the Chlorella basins reaches the

fishpond, little or no organic matter from the livestock

waste will remain, and any residual organic matter will be

instantly oxidized by some of the dissolved oxygen. The

nutrients are now readily available for enhancing the

prolific growth of different kinds of natural plankton that

feed the polyculture of 5 to 6 species of compatible fish.

No artificial feed is necessary, except locally grown grass

for any herbivorous fish.

 

The fish waste, naturally treated in the big pond, gives

nutrients that are used by crops growing in the pond water

and on the dykes.

 

Fermented rice or other grain, used for producing alcoholic

beverages, or silkworms and their wastes, can also be added

to the ponds as further nutrients, resulting in higher fish

and crop productivity, provided the water quality is not

affected.

 

Trials are taking place with special diffusion pipes

carrying compressed air from biogas-operated pumps to aerate

the bottom part of the pond, to increase plankton and fish

yields.

 

Apart from growing vine-type crops on the edges of the pond

and letting them climb on trellises over the dykes and over

the water, some countries grow aquatic vegetables floating

on the water surfaces in lakes and rivers. Others grow

grains, fruits and flowers on bamboo or long-lasting

polyurethane floats over nearly half the surface of the

fishpond water without interfering with the polyculture in

the pond itself. Such aquaponic cultures have increased the

crop yields by using half of the millions of hectares of

fishponds and lakes in China. All this is possible because

of the excess nutrients from the integrated farming systems.

 

Planting patterns have also improved. For example, rice is

now transplanted into modules of 12 identical floats, one

every week, and just left to grow in the pond without having

to irrigate of fertilize separately, or to do any weeding,

while it takes 12 weeks to mature. On the 13th week, the

rice is harvested and the seedlings transplanted again to

start a new cycle. It is possible to have 4 rice crops

yearly in the warmer parts of the country, with almost total

elimination of the back breaking work previously required.

 

Another example is hydroponic cultures of fruits and

vegetables in a series of pipes. The final effluent from the

hydroponic cultures is polished in earthen drains where

plants such as Lemna, Azolla, Pistia and water hyacinth

remove all traces of nutrients such as nitrate, phosphate

and potassium before the purified water is released back

into the aquifer.

 

Processing for added value and nutrient release

 

One big problem with agricultural produce is the drop in

prices when farmers harvest the same crops at the same time.

This is solved by the abundant supply of biogas energy,

which enable simple processing to be done such as smoking,

drying, salting, sugaring, and pickling.

 

Finally, the sludge from the anaerobic digester, the algae,

macrophytes, crop and processing residues are put into

plastic bags, sterilized in steam produced by biogas energy,

and then injected with spores for high-priced mushroom

culture.

 

The mushroom enzymes break down the ligno-cellulose to

release the nutrients and enrich the residues, making them

more digestible and more palatable for livestock. The

remaining fibrous residues can still be used for culturing

earthworms, which provide special protein feed for chickens.

The final residues, including the worm casting, are

composted and used for soil conditioning and aeration.

 

Sustainable development is possible

 

There has been a widespread misconception that the only

alternative to the dominant model of infinite, unsustainable

growth is to have no growth at all. I have heard some

critics refer to sustainable development as a contradiction

in terms. IFWMS, however, is a marvellous demonstration that

sustainable development is possible.

 

The key is a balanced development and growth that's achieved

by closing the overall production cycle, then using the

surplus nutrients and energy to support as many different

cycles of activities as possible while maintaining internal

balance, rather like a developing organism. The `waste' from

one production activity is resource for another, so

productivity is maximised with the minimum of input and

little or no waste is exported into the environment. It is

possible to have sustainable development after all; the

alternative to the dominant model of unlimited,

unsustainable growth is balanced growth.

 

Support our Sustainable World Global Initiative and sign up

for the First International Conference now

http://www.i-sis.org.uk/SWCFA.php

 

 

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