Al-Ahram Weekly Online   22 - 28 October 2009
Issue No. 969
Published in Cairo by AL-AHRAM established in 1875

Conversion of domestic solid waste into Ethanol

This process is the appropriate way to permanently solve the present domestic solid waste problems in Egypt writes, Essam Mitwally*

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This process is the appropriate way to permanently solve the present domestic solid waste problems in Egypt writes, Essam Mitwally

The world is facing a pandemic caused by the spread of the H1N1 virus, a.k.a. Swine Flu, and the WHO had classified it at the highest of its six-level system for classifying the global risk from disease. While the world is struggling to deal with this situation by providing effective vaccines, in quality and quantity, and prescribing routine cleanliness and healthy hygiene precautions, a new dimension suddenly erupted in Egypt that was not foreseen when the decision was made to slaughter all the pigs, a step that was described by health authorities as a misguided attempt to combat the swine flu. The problem became so severe that it was brought to the attention of the President and the governors of big cities like Cairo, Giza and Alexandria.

To shed some light on the origin of this problem, it should be noted that the domestic solid waste in Egypt, a.k.a. garbage, is rich in organic composition due mainly to leftover food waste. It is estimated that solid waste in Egypt's large cities is produced at the rate of 1 kg per person per day. In other words, Greater Cairo, with 17 million people, will produce daily 17,000 metric tons of solid waste, including street sweepings and construction debris. The average composition of this solid waste in Cairo is as follows: Food wastes 63.5%; Paper 14.0%; Metal 1.9%; Glass 2.0%; Plastics 2.9%; and Other 15.7%.

Garbage collection in Egypt was practiced by an army of garbage collectors, a.k.a. the Zabaleen. This practice has proven very profitable and well organized over the years. In addition to selling recycled items like metals, glass and paper, the food contents were sold to pig farms for pigs to feed on. The proceeds from this trade provided the bulk of the incentive to sustain this profession. The patrons of this organized profession became wealthy and powerful in their own domains.

Unfortunately, with the demise of Cairo's pig population, the source of this arrangement is gone and so is the incentive to collect the garbage from each and every household.

Extent of the problem

The result has been that rotting food piles up on the streets of middle-class neighborhoods like Heliopolis, Maadi and Zamalek, as well as in the streets of poorer communities like Imbaba and Dar Es Salam. The Governor of Giza supported by an army of young citizens made attempts to set an example for public participation in keeping the streets clean. The garbage was collected, but was transported to other areas such as Nahia and Saft-el-Laban, where it piled up, as many newspapers have reported.

Even if the Zabbaleen went back to work as before, their practice, though claimed by some to be the most thorough recycling method in the world, relies on primitive methods which do not correspond to the quantities of garbage produced daily in Egypt's large cities. This old way may have been sufficient for Cairo, for example, of the past 20-30 years, but it cannot, with its ancient methods and limited manpower, cater for the city's present needs.

The Appropriate sustainable solution

Even if garbage could be collected, it cannot be disposed of completely without considerable effort, let alone cost. The old advice of Reduce, Reuse and Recycle has proven ineffective and the practice of disposing waste in landfills, even if it could be done, is not sanitary because it does not follow environmental good practice of lining the landfills. Composting, on the other hand, produces carbon dioxide and is against good environmental practice in light of the global environmental problems of global warming and climate change.

The ONLY available solution that is both sustainable and profitable, while at the same time having other positive side- effects like keeping streets clean (thus reducing the health hazards facing the public especially children as well as improving the image of Egypt) is to convert these solid wastes which are rich in organic matters (cellulosic and hemi- cellulosic) into Ethyl Alcohol, a.k.a. Ethanol.

Ethanol production has been going on for years in countries like Brazil where it is produced from soy beans, mixed with gasoline and sold under the name Gasohol. In Canada, ethanol is produced using woodchips, and in the United States, it is produced using corn. Very recently the United States began experimenting using agricultural waste to produce ethanol and the first two bio-refineries in California are expected to begin operation later this year. A few months back, Sudan, with Brazilian support, commissioned an ethanol production bio-refinery using sugar cane molasses as the primary feedstock.

A Proposal for Egypt

The proposed project suggests converting the bulk of the collected refuse into ethanol. The process proposed is called "The Biomass Process" as laid out in the accompanying line diagram. This process is a unique hydrolysis technology designed to operate with distinct competitive advantages in an arena where there are few competing technologies. Hydrolysis is a chemical reaction in which a substance reacts with water and is changed into one or more basic substances. Chemically speaking, cellulose, hemi-cellulose, starch and sugars hydrolyze (i.e. break down) primarily into glucose, a simple sugar, and lignin. The sugars can then be processed to produce any of the 400,000 products produced in the plastic and petrochemical industries.

At this time, the most profitable product appears to be ethanol. The process involves continuous hydrolysis and fermentation using chemicals and biological catalysts, and is protected by patents and trade secrets. The simple sugars are fermented into ethanol, which is the primary economic product. One ton of raw unsorted solid waste, with 75% organic composition, will yield around 50 gallons of ethanol.

The lignin, along with any un-reacted celluloid material, is sent for pyrolysis. Pyrolysis is a chemical reaction in which a substance is decomposed by heat, in the absence of oxygen, into basic products such as methane and other gaseous fuels, diesel fuel, bunker fuel, carbon black, charcoal and other products. For example, plastics will typically pyrolyze about 85% by weight into diesel fuel.

Properties of Ethanol

Ethanol is a non-polluting oxygenated fuel that can be used as an additive to gasoline to increase its octane composition and to lower pollution from vehicles. Using the Biomass Process, ethanol will be refined quickly and easily from solid waste materials anywhere and can be stored for indefinite periods of time without deterioration. Ethanol has been referred to, by some, as "Nature's Perfect Fuel." When added to gasoline, ethanol:

— Extends motor fuel supplies;

— Replaces lead as an octane enhancer and suppressor of engine knock;

— Causes a major reduction in hydrocarbons, carbon monoxide and other pollutants emitted from vehicle exhaust; and

— May help avert a future motor fuel shortage.

Other advantages

The Biomass Process can permit ethanol production at a significantly lower price than do other comparable processes, and is thus competitive in the motor fuel market. This could signal one of the great technological and economic shifts of the modern age - a massive movement towards the use of renewable resources and recyclable products. In summary, this would result in some of the following benefits:

— Major reduction in airborne and in groundwater pollutants;

— Revolution in the disposal of municipal garbage and other solid waste materials;

— Employment of thousands in rural and urban centers;

— Slowing of the "Greenhouse Effect";

— Produce viable byproducts that meet or exceed all EPA requirements in Egypt; and

—Provide incalculable social benefits eliminating waste's harmful effects on the population, particularly small children.

Financial requirements

The present project proposes the establishment in Greater Cairo of a 500 ton/day solid waste conversion facility using the Biomass Process (Greater Cairo would ultimately need more than 30 such facilities). This would be the first phase of the overall process, and would serve as a pilot project, and its experience could lead to establishing additional centers, each of which could handle up to 1500 ton/day. The largest conventional recycling facility in the world currently handles 2100 ton/day in Southern California.

The cost of the license transfer, the equipment, the site and infrastructure, and training of operators, in addition to the needed collection and tipping trucks, constitutes the bulk of the required funding. A pre-feasibility study for a 500 ton per day facility shows that if a loan is requested for $60 million at 10% interest over five years, the annual bank payment plus salaries will be just over $16 million. This means that every year for five years, the refinery would break even. After that, it will net over $16 million annually. By World Bank standards, this is a very technically and economically feasible and profitable project. Using these proceeds, the next facility could then be built, and so on until the entire country is covered by facilities to transform the city's solid waste.

The Last Word

Such a proposal would bring a host of financial and administrative benefits to the government, the private sector, and individual communities, while at the same time providing sustainable and environmentally friendly solutions to Egypt's solid waste challenges.

* The writer is UN Senior Adviser (Retired)

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