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martes, 18 de abril de 2017

Profile: DADTCO – Small-scale processing for the cassava revolution in Africa





Introduction

The Blog has recently launched a new section about small-scale biorefining, a platform to promote small-sized biorefinery concepts and highlight their importance for the bioeconomy (it is complemented by a LinkedIn Group to share information and experiences). One of the resources available in the section is a list with references of companies and projects related to this field. This list will include a short overview and a link to a monographic post (profile) featuring in detail the company or the project. This post about Dutch Agricultural Development & Trading Company BV (DADTCO) is the first of the series.

The company
Web page: www.dadco.nl.
Twitter: @dadtconl.
Facebook: Dadtco.

DADTCO is a social enterprise pursuing poverty alleviation with entrepreneurial zeal, business methods and innovative courage. It was established in The Netherlands in 2002. It has its support office in that country and local offices in Nigeria, Mozambique and Ghana. Their stockholders believe that robust economic development in Sub Saharan Africa (SSA) should come from the establishment of private businesses that deliver sustainable and profitable high value end products, whilst directly and tangibly improving the health, living and income standards of the population.

Cassava is the major starchy food crop in SSA. Africa is the world’s number 1 cassava producer but has not developed any cassava processing industry because the very perishable cassava roots need to be treated within 24 hour of harvesting. DADTCO has implemented an innovative small-scale biorefining technology that has changed dramatically the way cassava is perceived, grown and processed in Africa. Together with its partners covers the whole cassava value chain: agricultural production with smallholder farmers, input supplies, processing and the marketing of the final product in local and international markets. Let us know more about its process concept and technologies.

Concept of small-scale and mobile processing

DADTCO invented a mobile cassava processing factory able to transform at village level cassava roots from smallholder farmers into food grade cassava cake or cassava starch flour. This breakthrough technology bridges the gap between farmers and large food companies. The company’s mobile cassava starch factories process fresh cassava on-farm or nearby, instead of attempting to transport the watery perishable crop over long distances to a central factory.

The mobile small-size concept overcomes four main obstacles to the commercialization of cassava across Africa: the high water content of the roots (65%-75%); the rapid perishability of the roots once harvested (must be used within 48 hours, preferably 24); its bulky and irregular shape; the wide scattering of smallholder farmers.

This technology consists of several mobile processing components that will be descripted in the next section. DADTCO has developed two scenarios in which to use the different units.
 - Scenario 1: A split processing solution.
The cassava roots are processed in situ in the cassava growing areas within 24 hours into a stable and easily transportable intermediate product with a long shelf-life. This intermediate product is called Cassava Starch Cake (CSC). The CSC is then transported either to DADTCO’s central flash dryer or an existing cassava starch plant for further refining.
- Scenario 2: A fully mobile solution.
The cassava roots are processed in situ in the cassava growing areas within 24 hours into a final product, Cassava Starch Flour (CSF). In this case, DADTCO adds a mobile drying unit to produce food grade cassava starch flour on site. The mobile plant will move three times per year to different cassava growing areas.

Figure 1. Two scenarios in the concept of small-scale and mobile processing of DADTCO (extracted from DADTCO web page)

Technologies

DADTCO’s mobile process consist of three parts: AMPU, MRU and dryer.

AMPU (Autonomous Mobile Processing Unit)
The AMPU processes fresh cassava roots into cassava cake. The whole mobile process is centered on a high speed rasper. This rasper is the smallest size technically possible machine while still being capable of releasing 98% of the starch granules in the roots. The rasper mechanically rips open the cell walls to release the starch. The lower the percentage of released starch, the higher the starch losses and subsequently financial losses.

Figure 2. AMPU sketch (extracted from DADTCO web page)

MRU (Mobile Refinery Unit)
The cassava cake coming from the AMPU is refined in the MRU to produce CSC. This unit, which fits in a 20 ft container which is based on its own dedicated chassis trailer, allows the extraction of cassava fibres from the cassava cake. The MRU and the AMPU have been designed to re-use water as much as possible from within its own process.

Figure 3. MRU sketch (extracted from DADTCO web page)

Processing capacity per hour
4 - 5 metric tons of cassava roots
Processing capacity per year (depends on daily operating hours and shift configurations)
30,000 metric tons of cassava roots
Production capacity per year (depends on daily operating hours and shift configurations)
15,000 metric tons of CSC

Flash Dryer (Scenario 1)
Its principle is simple. Very hot air (180°C) is sucked and mixed with the CSC inside a very long pipe up to 40 meters high and 1 meter in diameter. The CSC is passed through the pipe very quickly and is dried to CSF with about 11% moisture. The CSF and remaining air are separated from each other in a very large cyclone. The CSF is cooled down to ambient outside temperature and, subsequently, sieved off to mill down to less than 200 micron. The fraction consists of relatively large cassava fibres can be used in the production of chicken feed, soil improvers or even mosquito coils.

Production capacity per year
30,000 metric tons of CSF

Mobile Dryer (Scenario 2)
It is built in two 40 ft containers and the drying takes place in a fluid bed system. The bed of CSC is supported by a cushion of hot air jets. The method achieves intimate mixing without mechanical damage.

Processing capacity per day (two shifts per day basis)
48 metric tons of CSC
Production capacity per day (two shifts per day basis)
24 metric tons of CSF
Production capacity per year
7,200 metric tons of CSF

Products

CSC is a semi wet cassava paste that contains: 50% water, 49% released starch (98% on dry matter basis) and 1% fibres (1.5-2% on dry matter basis). It is packed in 20 kg plastic bags and has a shelf life of one year. The CSC can be transported to a central plant for further processing into an array of high value end products:
- CSF. It is a very white flour that contains only 1.5-2% fibres and 98% starch.
- Cassava starch.
- Cassava based syrups (maltose, dextrose and fructose).
- Modified starches (used in food preparation).
- Sorbitol (component in toothpaste, sweetener and humectant in cosmetics).
- Bioethanol.
- Beer, snacks and other foodstuffs.


Projects

Mozambique and Ghana

DADTCO’s business model has already proven successfully with SABMiller (currently, it is owned by AB Inbev), replacing imported malted barley with cassava starch in Impala beer in Mozambique and Eagle beer in Ghana. The farmers have experienced significant improvements in their livelihoods as a result of participating in the beer supply chain. Key to this success was DADTCO’s system of employing field mobilizers. The mobilizers coordinate harvesting times with smallholders to ensure farmers harvest only when there is sufficient demand from SABMiller for their crop. The company runs 2 AMPUs in Mozambique and 1 AMPU in Ghana.

Nigeria

In Nigeria, DADTCO transforms the cake into high quality cassava flour. This can replace up to 10% of wheat flour in bread and can be used as a substitute for wheat flour in biscuits. And the direct benefit is reducing the dependence on wheat importations. The government has mandated that flour must contain at least ten percent of cassava flour, opening a new market for DADTCO. The company runs 9 AMPUs in the country (3 in Taraba State, 3 in Osun State, 3 in Rivers State).

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REFERENCES
1 www.dadtco.nl (accessed on 1st April 2017).
2 The Rockefeller Foundation: “Reducing Post-Harvest Loss through a Market-led Approach”. May 2015.
3 “Mobile processing units unlock cassava markets in Africa”. Appropiate Technology, Vol. 42, No 1.
4 “Creating the Cassava Revolution”. DADTCO presentation.

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