Who's that knocking at my door and offering to fix all my waste problem?

July 10, 2024 | 08:56 pm PT
Paul A. Olivier
Suppose you run a restaurant and are tired of wasting money on bottled gas. Suppose you cringe every time you see your food waste being hauled away in a garbage truck and dumped in a stinky landfill.

Suppose someone comes knocking at your office door and tells you that she will give you, free-of-charge, all of the fuel that you need for cooking, so that you no longer have to pay over VND25 million or US$1,000 per month for bottled gas. (Some restaurants in Vietnam pay twice this amount.) She then tells you that she will haul away all of your food waste without charging you a penny. Would you refuse such an offer? I doubt it.

Think about it. The restaurant would not have to burn fossil fuels to cook, boil, bake or roast. Instead, it would use combined heat and biochar gasifiers, gasifiers that easily meet all the emission standards of the World Health Organization. Updraft and downdraft gasifiers, running on pellets, can produce a steady stream of high-grade heat for as long as needed.

When one ton of rice hull pellets is gasified, about 400 kg of rice hull biochar are produced. One ton of high-quality rice hull biochar sells in Vietnam for about VND25 million. Therefore, the 400 kg of biochar produced has a value of VND10 million. The cost to make one ton of rice hull pellets is about VND1 million or US$40 (including the cost of the biomass).

So, the gasification of one ton of rice hulls involves a 10-fold increase in value. Yes, the restaurant has free fuel, but the lady supplying pellets in exchange for biochar also makes a lot of money.

Note well that the pellets needed to fuel gasifiers can be derived from agricultural by-products, forestry debris or woody biomass from invasive plants. Hundreds of millions of tons of such low-grade biomass are available each year in Vietnam.

Vietnam, for example, produces about 9 million tons of rice hulls and about 97 million tons of rice straw each year, all of which can be pelleted and used as gasifier fuel. Most of this precious biomass, however, gets uselessly dumped or burned. This gives rise to horrendous environmental damage.

The lady knocking at the restaurant door also supplies stainless steel fermentation buckets equipped with butterfly valves. Note well that fermentation, for the most part, takes place in the restaurant. Fermentation buckets filled with food waste can be left in the restaurant for several weeks without spoilage or the need for refrigeration. Fermented food waste easily replaces commercial feed such as corn and soybean meal.

A bit of biochar produced by the restaurant is added to the fermenting food waste to provide a lot of space for fermentation microbes to do their job. A highly quality biochar can have a surface area ranging from 250 to 660 square meters per gram. This enormous space greatly enhances and accelerates the fermentation process.

The lady knocking at the restaurant belongs to a social enterprise run by three ladies with a sturdy background in marketing. These three ladies also work with small farmers who belong to the same social enterprise. The ladies educate, train and equip these small farmers. They also arrange the transport of food waste to the farmers and give this precious waste resource to them free-of-charge.

The farmers then transform food waste into feed and fertilizer, and the meat and vegetables that they produce get delivered back to the restaurants. It's quite simple: food waste from restaurants to farmers, and food from farmers back to restaurants. Trucks do not travel empty, and all aspects of food production and consumption are localized.

I suggest that these three ladies should earn 20% on the sale of food to restaurants, and farmers should earn 80%. Some farmers near Da Lat make no more on average than about US$175 each year, and many are bogged down in loan shark debt and make nothing at all from year to year.

If there are 100 farmers in the social enterprise, and if each farmer produces about VND1 billion of food each year, these three ladies can earn VND20 billion per year.

It is easy to imagine that farmers, with about an hectare of inter-cropped farmland, could produce twice this amount of food and hence make twice the amount of money mentioned above. These farmers never have to buy chemical fertilizers, pesticides, herbicides, fungicides, antibiotics or growth hormones in the raising of plants and animals. On these farms, multiple plants systems support multiple animal systems and vice versa. Poultry and animals are raised indoors on odorless, fly-free and disease-free bedding where all of their comfort, behavioral and nutritional needs are met.

The fresh manure of a pig that eats fermented food waste can be collected each day off bedding. It can then be fermented in the same way as food waste and fed to chickens or ducks. The manure of the chicken or duck can be fed to fish, and the wastewater of the fish can be routed to plants (aquaponics). The waste of the pig, chicken, duck or fish can generate far more value over its lifetime than when that creature is sold.

The urine of the pig gets mesophically immobilized in bedding, and a good portion of the bedding gets transformed into microbial biomass of a high crude protein content. The farmer uses spent bedding to fertilize plants grown in soil.

In conclusion, restaurants have safe food at reasonable prices. The cost of landfilling food waste is eliminated. Parasitic middlemen involved in selling feed, fertilizer, fuel and biochar to farmers are also eliminated, as well as middlemen who buy food from farmers at ridiculously low prices. Markets, supermarkets and even farmers markets are out of the picture.

Bottled gas becomes a thing of the past and so do stinky landfills that pump out 16% of the world’s total methane. The useless burning of agricultural waste and forestry debris is eliminated. Fossil fuels are no longer needed for cooking and can be left in the ground where they belong.

What I have outlined above is not a charity but a big business firmly grounded in transforming waste at the highest possible levels - a big business firmly grounded in infinitely self-renewing food cascades and loops. Here we have a simple strategy in which the market value of food is not allowed to override broader issues relating to food safety, food security, food justice, food sovereignty, income inequality, the health of the environment and the biodiversity of our planet.

Marvelous things happen when people do not waste waste and when they live in harmony with the natural world. For more information on how all of this works, please see Waste Transformation Closed Loop Farming.

*Dr. Paul Olivier is a U.S. expat and environmentalist who lives in Da Lat.

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