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By Fabio Nunes, poultry processing consultant, Curitiba, PR, Brazil
On April 12, 1961, from the small spaceship Vostok-1 which gravitated at an altitude of 302 km around the globe, Russian Yuri Gagarin, the first human astronaut, exclaimed “The earth is blue!”. The blue colour that enchanted the young astronaut was the colossal mass of water that covers some 70% of the earth’s surface and accounts for a net volume of approximately 1.5 billion of cubic kilometers. This huge amount of water on the surface of the planet is fixed, with the form and location varying over space and time: saltwater in oceans, freshwater in glaciers, water in the atmosphere, etc. However, just 2.5% of this huge volume is suitable for human consumption and for use in agricultural production (Figure 1).Humans have little or no control over most of this water. Most investment concentrates on water in rivers and lakes, but soil moisture and groundwater, together, account for 98% of the world’s available freshwater. Many people worry about how much drinking water is available, not realising that agriculture dominates human water use. According to UNESCO, presently 67-68% of all water withdrawn for human use, on a global basis, is soaked up by agriculture, mostly in the form of irrigation. Industry accounts for 23% and domestic use as drinking water and for sanitation accounts for about 8% of the total consumption. Each day, a person drinks 2 to 4 litres of water, but eats food that requires 2,000 to 5,000 l of water in its production. These averages mask considerable variation.
Broiler least demanding
These global averages vary a great deal across regions and continents. In Africa the agricultural use of water sucks away 88% of all water withdrawn for human use, domestic and industry accounts, respectively, for 7% and 5% only, and in the EU 54% of the water available is used in industry, while agriculture and domestic use account for 33% and 13% of the total use, respectively.
These global averages vary a great deal across regions and continents. In Africa the agricultural use of water sucks away 88% of all water withdrawn for human use, domestic and industry accounts, respectively, for 7% and 5% only, and in the EU 54% of the water available is used in industry, while agriculture and domestic use account for 33% and 13% of the total use, respectively.
Among the protein animal production chains, broiler production is the least-water user, demanding 3,900 litres to produce 1 kilogram of meat, while beef demands 15,500 l/kg and pork 4,900 l/kg. Water is a key-player throughout the entire poultry production chain, being of vital importance from farm to plant. In the plant the importance of the water is significant, as it is used to cool birds down while on the holding shed, to secure the high-level standard of hygiene demanded by the products, installations, work clothing, personnel and utensils; to carry over the process’ by-products and debris; to improve the processing yield and, last but not least, to quench the workers thirst!
Three step operation
The source of water used in poultry processing plants varies among countries. It can be either supplied by the municipality, or outsourced from underground by means of artesian wells, the commonest and cheaper source throughout Latin America as a whole, Brazil included.
The source of water used in poultry processing plants varies among countries. It can be either supplied by the municipality, or outsourced from underground by means of artesian wells, the commonest and cheaper source throughout Latin America as a whole, Brazil included.
The sanitary requirement to wash and disinfect trucks and crates prior to travelling back to the farms, which is mandatory in some countries, while just customary in some others, makes this three-step operation - immersion in water for solid material loosening, high-pressure foaming/washing and high-pressure rinsing, the heaviest water user in the area. In opposition to the water single-usage cycle of the old washers, the modern ones have been designed to move crates and water in counter-flow, making use of the water in a saving multi-usage cycle. However, as older generations of equipment still predominate, water consumption in this area of the plant will be high for a longer period of time.
Replenishing stunning tubs
The majority of broilers are still stunned electrically, which hardly depend on water to work. Although relatively small, the demand by the stunner is continuous as the tub level must be continuously replenished to replace the water broilers carry over while travelling through.
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| Yet relatively small, the water demand by the stunner is continuous as the tub level must be continuously replenished to replace the water (photo Marel Stork). |
To keep the live reception clean, companies should think of alternative solutions to the common “water broom”, which is often negligently and wastefully used. Dirt from crates can be accumulated underneath the transportation belt, either contained on the floor by bumps built along side the transportation belt or onto a suspended tray. Any other minor solid debris can be swept away by using rakes. Never clean, but recycled water instead - from the chilling line, the lungs vacuum pumps, rain accumulation tanks and others – is the suggestion to wash the area down when necessary.
Large scalding tanks
The commercial failure of hot-air scalding dismisses, apparently forever, the dream to scald birds using just 50 ml of water per carcass, among some other great benefits the system claimed to offer. So, the industry continues to be dependent on the heavy-weight water users of conventional scalding tanks. The massive water consumption of this process derives from the old, mammoth sized tanks still largely present in the plants, from the need to comply with the sanitary regulations in force in some countries which requires the tank to be fully drained and refilled a number of times a day and the tank water replenished throughout the working hours, and from the wasteful management of the process in some others, as well.
The commercial failure of hot-air scalding dismisses, apparently forever, the dream to scald birds using just 50 ml of water per carcass, among some other great benefits the system claimed to offer. So, the industry continues to be dependent on the heavy-weight water users of conventional scalding tanks. The massive water consumption of this process derives from the old, mammoth sized tanks still largely present in the plants, from the need to comply with the sanitary regulations in force in some countries which requires the tank to be fully drained and refilled a number of times a day and the tank water replenished throughout the working hours, and from the wasteful management of the process in some others, as well.
Scalding tanks of 50,000 litres volume are still very common industry wide. So, in a plant scalding 10,000 bph for 16h/day, for 25 days/month and 12 months/year in a tank like that and required to drain down and refill the tank just once a day, the consumption of water to accomplish this requirement reaches 30 million litres annually. Furthermore, to comply with the additional fresh make-up water requirement of 0.5 litre/carcass/h, an extra 24 million litres of water are consumed annually, totalling, in the tank only, 54 million litres of water annually.
The subsequent three pluckers defeathering line demanding some 0.5 l of water per bird, accounts for an extra consumption of 24 million litres of water annually. In total, the scalding and plucking department only, accounts for a consumption of 78 million litres of water annually. Giving a person needs 104 litre of water a day, as per the WHO recommendations, that consumption equates to a city of 750,000 inhabitants.
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Source: World Poultry, Vol. 27, No. 10, 2011
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