Tag Archives: cellulose

Date Palm Wastes as a Biomass Resource

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Date palm is one of the principal agricultural products in the arid and semi-arid region of the world, especially Middle East and North Africa (MENA) region. There are more than 120 million date palm trees worldwide yielding several million tons of dates per year, apart from secondary products including palm midribs, leaves, stems, fronds and coir. The Arab world has more than 84 million date palm trees with the majority in Egypt, Iraq, Saudi Arabia, Iran, Algeria, Morocco, Tunisia and United Arab Emirates.

date-wastes

Date palm biomass is found in large quantities across the Middle East

Egypt is the world’s largest date producer with annual production of 1.47 million tons of dates in 2012 which accounted for almost one-fifth of global production. Saudi Arabia has more than 23 millions date palm trees, which produce about 1 million tons of dates per year.

Biomass Potential of Date Palm Wastes

Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits. Some studies have reported that Saudi Arabia alone generates more than 200,000 tons of date palm biomass each year.

Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in dates-producing nations. In countries like Iraq and Egypt, a small portion of palm biomass in used in making animal feed.

The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date biomass an excellent waste-to-energy resource in the MENA region.

Technology Options for Date Palm Biomass Utilization

A wide range of thermal and biochemical technologies exists to tap the energy stored in date palm biomass to useful forms of energy. The low moisture content in date palm wastes makes it well-suited to thermochemical conversion technologies like combustion, gasification and pyrolysis which may yield steam, syngas, bio oil etc.

On the other hand, the high volatile solids content in date palm biomass indicates its potential towards biogas production in anaerobic digestion plants, possibly by codigestion with sewage sludge, animal wastes and/and food wastes. The cellulosic content in date palm wastes can be transformed into biofuel (bioethanol) by making use of the fermentation process.

The highly organic nature of date palm waste makes it highly suitable for compost production which can be used to replace chemical fertilizers in date palm plantations. Thus, abundance of date palm trees in the MENA and the Mediterranean region, can catalyze the development of biomass and biofuels sector in the region.

Zero Waste Trends to Watch

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Most people have heard about concepts such as single-stream recycling, but there’s another approach known as zero waste. People who support the concept of zero waste agree that, in a broader sense, it means reducing dependence on landfills and increasing reliance on material recovery facilities. But, after that, the definition varies primarily based on industries, manufacturers and even entire countries.

Even so, there are inspiring trends that show how people and companies are working hard to reduce the amount of waste produced, thereby getting ever closer to that desirable zero benchmark. Below are some of the major trends taking place across the world in the field of zero waste:

Circular-Economy

More Reusable Packaging

We live in a world where it’s possible to order almost anything online and have it quickly arrive on a doorstep — sometimes the same day a person placed the order. And, society loves the convenience, but the dependence on delivered products causes an increase in packaging materials.

It is often astounding how many packing peanuts, layers of bubble wrap and cardboard cartons come with the things we buy. And, the manufacturers and shipping companies consistently bring up how boxes get dropped or otherwise mishandled during transit, making the extraordinary amounts of protective packaging products necessary.

packaging-LCA

Packaging that adorns your product can have serious environmental impact.

On a positive note, a company called Limeloop makes a shipping envelope designed from recycled billboard wrapping people can reuse thousands of times. Another company called Returnity communicates with distributors to urge them to use the establishment’s boxes and envelopes, both of which people can rely on dozens of times instead of throwing them away after single uses.

If you are a business looking to adopt eco-friendly practices, you should read this article on green packaging methods.

Ceramic Mugs in British Coffee Shops

In some regions of the world, customers who visit coffee shops don’t get asked whether they’ll be drinking their coffee on site or taking it with them to go. However, many leading coffee shops in the United Kingdom find out that detail from customers who order drinks, then serve the beverages in non-disposable mugs to people who’ll enjoy their purchases on the spot.

Also, all 950 Starbucks locations in Great Britain recently began charging customers five cents for getting their drinks in disposable cups. Conversely, it rewards them by taking 25 cents off the costs of their orders when they bring reusable cups into the stores.

Creative Ways to Cut Down on Farm Waste

Manure (or fertilizer) is a reality on farms around the world. And, the commercially bought versions of it contribute to excessive waste and inflated costs. Some even harm future growth when farmers apply manure too heavily and negatively affect the soil’s balance.

But, besides avoiding commercially-sold manure and not applying it excessively if used, what else can people in the agriculture sector do to make farm waste more manageable? They can look for unique outlets that may want to buy it.

Agriculture_Waste_Biogas

One startup uses a detailed manure-refining process to extract the cellulose from cow dung. Business representatives then use the cellulose — a byproduct from the grass and corn cows eat — for a new kind of fabric.

What about using animal waste for energy? A forward-thinking farmer did that with his manure lagoons, making them produce biogas that powers homes.

These unusual solutions highlight unconventional use cases for animal droppings, such as poultry litter, that support zero-waste goals, provided farmers want to explore them.

An Uptick in Reusable Food Containers

People often pack their lunches in plastic containers before heading off to work, but when they get food delivered or pick it up from a provider to eat at home later, the associated containers usually fill up garbage cans after people chow down.

Some facilities are trying to change that. At The University of California Merced campus, a pilot program occurred where students who stopped by dining halls for meals to take away brought reusable containers with them. After people ate the food from them, they could return them to get washed and ready for future meals.

Moreover, a pizza restaurant in Wales provides an aluminum box for people to use again and again when taking their pies home. One of the problems with cardboard pizza containers is they can’t be recycled when contaminated with grease. However, people can buy the metal ones for a small, one-time fee.

Opt for reusable containers for food and beverages

Then, by using them, they get 50-cent discounts on their pizza. The restaurant also backs the boxes with a lifetime guarantee and will replace them for no charge if necessary due to breakage or damage. Also, because metal conducts heat, the material helps pizza stay hotter for longer than it would in cardboard boxes.

Innovations to Complement Commitment

Adhering to a zero waste lifestyle undoubtedly requires dedication and a willingness to look beyond old habits. However, for people who show those characteristics, numerous inventions and improvements make it easier to do away with the throw-away culture.

Biochemical Method for Ethanol Production

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Ethanol from lignocellulosic biomass is produced mainly via biochemical route. The three major steps involved in the biochemical method for ethanol production are pretreatment, enzymatic hydrolysis, and fermentation. Biomass is pretreated to improve the accessibility of enzymes. After pretreatment, biomass undergoes enzymatic hydrolysis for conversion of polysaccharides into monomer sugars, such as glucose and xylose. Subsequently, sugars are fermented to ethanol by the use of different microorganisms.

Bioethanol-production-process

Pretreated biomass can directly be converted to ethanol by using the process called simultaneous saccharification and cofermentation (SSCF). Pretreatment is a critical step which enhances the enzymatic hydrolysis of biomass.

Basically, it alters the physical and chemical properties of biomass and improves the enzyme access and effectiveness which may also lead to a change in crystallinity and degree of polymerization of cellulose. The internal surface area and pore volume of pretreated biomass are increased which facilitates substantial improvement in accessibility of enzymes. The process also helps in enhancing the rate and yield of monomeric sugars during enzymatic hydrolysis steps.

Pretreatment methods can be broadly classified into four groups – physical, chemical, physio-chemical and biological. Physical pretreatment processes employ the mechanical comminution or irradiation processes to change only the physical characteristics of biomass. The physio-chemical process utilizes steam or steam and gases, like SO2 and CO2. The chemical processes employs acids (H2SO4, HCl, organic acids etc) or alkalis (NaOH, Na2CO3, Ca(OH)2, NH3 etc).

The acid treatment typically shows the selectivity towards hydrolyzing the hemicelluloses components, whereas alkalis have better selectivity for the lignin. The fractionation of biomass components after such processes help in improving the enzymes accessibility which is also important to the efficient utilization of enzymes.

The pretreated biomass is subjected to enzymatic hydrolysis using cellulase enzymes to convert the cellulose to fermentable sugars. Cellulase refers to a class of enzymes produced chiefly by fungi and bacteria which catalyzes the hydrolysis of cellulose by attacking the glycosidic linkages. Cellulase is mixture of mainly three different functional protein groups: exo-glucanase (Exo-G), endo-glucanase(Endo-G) and ?-glucosidase (?-G).

The functional proteins work synergistically in hydrolyzing the cellulose into the glucose. These sugars are further fermented using microorganism and are converted to ethanol. The microorganisms are selected based on their efficiency for ethanol productivity and higher product and inhibitors tolerance. Yeast Saccharomyces cerevisiae is used commercially to produce the ethanol from starch and sucrose.

Escherichia coli strain has also been developed recently for ethanol production by the first successful application of metabolic engineering. E. coli can consume variety of sugars and does not require the complex growth media but has very narrow operable range of pH. E. coli has higher optimal temperature than other known strains of bacteria.

Lower GHG emissions and empowerment of rural economy are major benefits associated with bioethanol

The major cost components in bioethanol production from lignocellulosic biomass are the pretreatment and the enzymatic hydrolysis steps. In fact, these two process are someway interrelated too where an efficient pretreatment strategy can save substantial enzyme consumption.

Pretreatment step can also affect the cost of other operations such as size reduction prior to pretreatment. Therefore, optimization of these two important steps, which collectively contributes about 70% of the total processing cost, are the major challenges in the commercialization of bioethanol from 2nd generation feedstock.

Enzyme cost is the prime concern in full scale commercialization. The trend in enzyme cost is encouraging because of enormous research focus in this area and the cost is expected to go downward in future, which will make bioethanol an attractive option considering the benefits derived its lower greenhouse gas emissions and the empowerment of rural economy.