时间：2022-06-13 05:47:37
Philip Charles Glatz1 and Belinda Kay Rodda2
1. Pig and Poultry Production Institute, Roseworthy Campus, Roseworthy 5371, South Australia
2. Pig and Poultry Production Institute, Nutrition Laboratory, Roseworthy Campus, Roseworthy 5371, South Australia
Received: August 15, 2011 / Accepted: September 13, 2011 / Published: February 20, 2012.
Abstract: A survey of major chicken meat hatcheries in Australia was undertaken in 2008 to identify how hatchery waste is currently managed. A weekly average of 10.4 tonnes of waste is produced by chicken meat hatcheries. The cost of disposal (average$127/tonne) and availability of disposal sites is an emerging issue. The majority of hatchery waste is sent to land fill or for composting, with some rendered for use as pet food. Hatchery wastewater is mostly used for irrigation or disposed directly into the sewer. Most of the hatcheries have no environmental issues with hatchery waste on site but some report odour problems. Some hatcheries would like to treat the waste on site so that it could be sold as a commodity or to use methods to separate liquid from solid waste and recycle water.
Key words: Hatchery waste, survey, poultry, environment, waste management.
1. Introduction??
Large quantities of hatchery waste needs to be disposed every day in Australia from chicken meat hatcheries. Generally this waste is sent to land fill or composted. This requires storing the waste on site and then transporting to land fill areas or to compost sites. The poultry industry produces large amounts of hatchery waste which includes solid waste and wastewater. The solid hatchery waste comprises empty shells, infertile eggs, dead embryos, late hatchings and dead chickens and a viscous liquid from eggs and decaying tissue. The wastewater comes from water used to wash down incubators, hatchers and chick handling areas [1].
Traditional disposal methods for solid hatchery waste include land fill, composting, rendering, and incineration. Most of the hatchery waste is sent to land fill or composting, which costs the chicken meat industry millions of dollars each year in disposal costs [1].
The costs of disposing hatchery waste to land fill or for composting are increasing. In addition dwindling waste disposal sites and environmental issues at hatcheries and at land fill sites has necessitated the need to examine alternative methods of handling and treating hatchery waste at hatcheries.
This paper reports on a survey of major hatcheries in Australia to identify how hatchery waste is managed.
2. Methods
Hatchery Survey
A questionnaire was developed in collaboration with the chicken meat industry to identify how hatchery waste is managed, the nature of the waste, current difficulties being faced, new methods of stabilising the waste, and staff perceptions and attitudes to treating hatchery waste. The questionnaire was sent to 17 major chicken meat hatcheries in Australia; 15 replies were received. The questions in the survey were as follows.
Question:
What is the size of the hatchery?
How many eggs are set per week?
(1) Solid waste
What tonnage of waste is produced weekly?
Describe the major components of the solid waste.
Is there any separation of the solid waste before disposal?
(2) How is the solid waste handled on site?
How is the solid waste handled in the hatchery?
What is the time involved in removing the waste from the hatchery to the waste bin?
Is there any disinfection or treatment of waste before disposal?
What are the major problems associated with handling of the waste?
(3) How is solid waste disposed?
Where is the waste sent? Specify the location.
What is the cost of waste disposal ($/tonne)?
How frequently is waste removed from the hatchery?
What are the current treatments now available for hatchery waste?
If treated, how are the products used?
How is wastewater disposed?
Is there recycling of wastewater?
(4) Are any processing techniques used?
Is there any processing of waste on site?
Do you know any new techniques in Australia to manage waste on site?
If yes, what is the cost for treatment of the waste?
How is the treated waste used?
What investment would the company be prepared to make on processing the waste?
(5) Wastewater
What volume of water (kL/week) is used to clean the hatchery weekly?
How is the wastewater treated?
Is treated wastewater recycled?
How is the wastewater disposed?
(6) Environmental issues
Are there any issues (odour, contamination etc.) of having waste on site?
How often is waste removed from the hatchery?
Are there any complaints from staff or neighbours?
Does land fill cause a problem for nearby farms?
Does the site have or need an Environmental Management Plan that incorporates waste disposal?
(7) Attitudes to waste management
Is hatchery waste smelly and not easy to manage at the hatchery? (tick one of the boxes)
Strongly agree Agree
Disagree
Strongly disagree Is training of staff required to manage the waste on site? (tick one of the boxes)
Strongly agree Agree
Disagree
Strongly disagree It is not worth developing alternative methods to manage the hatchery waste on site? (tick one of the boxes)
Strongly agree Agree
Disagree
Strongly disagree
Would you be interested in investing in a system that treats the waste on site and stabilises the waste?
Do you have any further opinions on how hatchery waste can be managed or treated?
3. Results
3.1 Hatchery Solid Waste
3.1.1 Tonnes of Waste Produced Weekly
An average of 10.4 tonnes of waste/week is produced with a range of 3-22.5 tonnes/week produced by the surveyed hatcheries (Table 1).
3.1.2 Describe the Major Components of the Waste
When asked to describe the major components of the hatchery solid waste 33% of the respondents reported the waste to be empty shells, infertile eggs, dead embryos, late hatchings and dead chickens; 20% indicated the waste was mainly egg shell and dead embryos while 13.4% reported the waste was mainly egg shell. Other descriptions of the main components of the waste were: (1) egg shell and egg yolk; (2) egg shell and dead chickens; (3) empty shells, infertile eggs, dead chickens (culls); (4) fluid and egg shell and (5) egg shells, fluff, unhatched embryos and culls (Table 1).
3.1.3 Separation of Solid Waste
33.3% of surveyed hatcheries separated the waste before disposal. Methods reported were:
Non fertile eggs at 18 day stage of incubation
were placed in a separate container;
Shells and fluid separated;
Excess liquid pumped into a separate bin(Table 1).
3.2 Handling of Solid Waste on Site
3.2.1 How Is Solid Waste Handled in Hatchery?
When asked about the method used to dispose solid waste 26.7% of the surveyed hatcheries place the waste manually into a waste bin or silo. The majority of hatcheries use a vacuum extraction system to transfer the waste into bins. Other specific handling methods were: (1) hatchery waste is stored in a cool room and then placed in a Bio-Bin; (2) waste is crushed before use of a vacuum or auger system to transfer the waste into a bin or (3) culled chicks are macerated and added to the waste bin (Table 2).
3.2.2 Time and Labour Involved in Handling Waste
Over half of the hatcheries indicated there is a time and labour cost involved in removing the waste; 33.3% of the hatcheries used an automated system while one hatchery manager indicated 2 or more people were needed to handle the waste. Staff time required to remove the waste from the surveyed hatcheries ranged from 0.5-15 h/week (Table 2).
3.2.3 Disinfection and Treatment of Waste before Disposal
Most of the hatcheries (86.7%) did not disinfect or treat the waste before disposal. One hatchery held the waste in a cool room while another hatchery did disinfect the waste. One hatchery crushed the waste to allow the maximum amount of waste to be placed into the waste bin (Table 2).
Table 1 Hatchery size, eggs set/week, waste produced and major components of waste.
3.2.4 Major Problems Associated with Handling Waste
20% of the surveyed hatcheries believe there is no major problem in handling the hatchery waste, particularly with use of the automated system. The remainder of the hatcheries have different problems including cost of disposal, finding disposal sites, odour, high percentage of liquid, high water use needed to facilitate separation, vacuum system blockages, spillage (at hatchery and during transport), staff health issues, flies, noise and abrasiveness of the egg shell (Table 2).
Table 2 Time, labour and problems involved with handling of solid waste.
3.3 How Is Solid Waste Disposed?
3.3.1 Where Is Waste Sent?
Four of the hatcheries reported they know where the waste is sent but do not know what it is used for. Other hatcheries send waste for composting, land fill, processing and rendering (Table 3).
3.3.2 Cost of Waste Disposal
The average cost for waste disposal is $127.3/tonne, with a range from $55-$317/tonne for the surveyed hatcheries.
3.3.3 Frequency of Waste Removal
The waste is removed on average 4 times/week(range of 2-7 times/week) across all surveyed hatcheries.
3.3.4 Current Treatment Methods for Hatchery Waste
Current disposal methods are land fill (28.6%), both composting and land fill (14.3%), both rendering and composting (14.3%), through a crusher (7.1%), processing (7.1%) and incineration and recycling(7.1%). Two hatchery respondents did not know what happened to the waste and one hatchery manager did not give a response (Table 3).
3.3.5 How Are Waste Products Used?
When the hatchery managers were asked about how the products are used after treatment, 50% of surveyed hatcheries said the question did not apply to their waste while one hatchery said the waste was used for composting and fertiliser. One hatchery manager said it was used to produce poultry meal while another manager said the waste was used for pet feed (Table 3).
Table 3 Waste disposal cost, frequency of removal, current treatments, products and wastewater management.
3.3.6 How Is Waste Water Disposed?
Hatchery wastewater is used for irrigation by 38.5% of surveyed hatcheries, and 15.4% of the hatcheries dispose wastewater directly into the sewer. One hatchery used a wastewater treatment system; one hatchery used a sewage/treatment system, and another hatchery disposed wastewater into a waste lagoon. The rest of the hatcheries sent wastewater to land fill, disposing it in a similar manner as the solid waste(Table 3).
3.3.7 Recycling of Wastewater
Most of the hatcheries (85.7%) do not recycle water. One hatchery recycled the hatching tray washer water, while another used the wastewater to irrigate paddocks (Table 3).
3.4 Techniques for Processing Waste
3.4.1 Is There Processing of Waste on Site?
80% of surveyed hatcheries did not process waste on site, others kept the waste in the cool room or a Bio-Bin (Table 4).
3.4.2 Any New Techniques Known to Manage Waste on Site
92.8% of surveyed hatchery managers do not know any techniques to manage waste on site; only one manager suggested waste could be composted on site(Table 4).
3.4.3 Cost of Treating Waste on Site
None of the respondents knew how much it would cost for a waste treatment system (Table 4).
3.4.4 If Waste is Treated on Site, How Is It Used? No responses were received for this question(Table 4).
3.4.5 What Investment Would the Company Make for Processing Waste?
66.7% of surveyed managers said they do not know what investment the company would be prepared to make on processing waste. However, 16.7% thought that reducing cost of waste disposal to land fill would be a good investment; others would like an investment on better separating systems and recycling (Table 4). 3.5 Wastewater
3.5.1 Volume of Wastewater Used
The average volume of water used in hatcheries is 238.4 kL/week, ranging from 50-324 kL/week for the surveyed hatcheries (Table 5).
3.5.2 How Is the Wastewater Treated?
40% of the hatcheries do not treat the wastewater. Other hatcheries treat the wastewater using: (1) aerated ponds and then use the water for irrigation; (2) enviroflow water recycling system and (3) solids separated before irrigation on paddocks (Table 5).
3.5.3 Is Treated Wastewater Recycled?
Most of the hatcheries (85.7%) do not recycle water. One hatchery recycled the hatching tray washer water, while another used the wastewater for irrigating paddocks (Table 5).
Table 4 Processing of waste, techniques, costs of treatment, use of treatment waste and potential investments.
Table 5 Wastewater treatment, recycling and disposal.
3.5.4 How Is Wastewater Disposed?
Hatchery managers report that wastewater is disposed by irrigation (30% of hatcheries), through an enviroflow unit (10%), via the sewage system (30%), through a septic system (10%) and via an evaporation area (Table 5).
3.6 Environmental Issues
3.6.1 Are There Any Issues Having Waste on Site?
36.4% of the hatchery managers said there are no environmental issues from having the waste on site. A further 18.2% said they have no major problems, but do have an issue with odour. However, 27.3% of the managers said odour is the major issue; 18.2% said the combination of odour, contamination and vermin are major problems (Table 6).
3.6.2 How Often Is Waste Removed from Hatchery?
The waste is removed an average of 4 times/week(range of 2-7 times/week) across all surveyed hatcheries (Table 6).
3.6.3 Any Complaints from Staff or Neighbours?
Most of the managers said there were no complaints from staff or neighbours. One hatchery reported that neighbours do complain about odour when it is pick up day for their waste bin. This hatchery was located 6 km from the CBD of a major city (Table 6).
3.6.4 Does Land Fill Cause a Problem for Nearby Farms?
When hatchery managers responded to the question does land fill cause a problem for nearby farms, 50% said no, 40% did not answer and 10% said they do not send waste to land fill (Table 6).
3.6.5 Does the Site Have or Need an Environmental Management Plan for Waste Disposal?
57.1% of the managers think there is a need for EMP and 35.7% think there is no need. One manager reported that waste disposal is regulated by the local council (Table 6).
3.7 Attitudes to Waste
(a) Hatch Waste Is Smelly and Not Easy to Manage
When asked if the hatchery waste is smelly and is not easy to manage 35.7% of surveyed managers strongly agreed; 14.3% agreed while 50% disagreed(Table 7).
(b) Training of Staff Required to Manage Waste
All managers agreed or strongly agreed that staff need to be trained to manage the waste on site (Table 7).
(c) Developing Alternative Methods to Manage Waste on Site Is Worth the Effort
76.9% of managers agreed or strongly agreed that developing alternative methods to manage the hatchery waste is worth the effort (Table 7).
Table 6 Environmental issues associated with hatchery waste.
Table 7 Attitudes to waste management by hatchery staff.
3.7.2 Would There Be Interest in Investing in a System That Treats the Waste?
When managers were asked if the hatchery would be interested in investing in a system that treats the waste on site and stabilises it, the answers varied, 33.3% said yes to further investment; 20% said no; 13.3% said it would be worth consideration; 13.3% said only if it was practical and affordable. One manager indicated they would be interested provided it did not require extra labour while 2 respondents indicated it was not their decision (Table 7).
3.7.3 Further Opinions on How Hatchery Waste Can Be Managed
Hatchery managers were asked for further opinions on how hatchery waste could be treated. Most of the managers provided no further comment; some managers had the following suggestions:
treat the waste (e.g. composting) so it could be sold as a commodity;
develop a method to separate liquid from shell to produce value added products;
recycle water;
have a silo to store waste until it is trucked away(Table 7).
4. Discussion
The average volume of water used in hatcheries is 238.4 kL/week. The majority of hatcheries use a vacuum extraction system to transfer the waste into bins; others place the waste manually into a bin or silo. Some of the hatcheries separate the waste before disposal. About 20% of the surveyed hatcheries believe there is no major problem in handling the hatchery waste, particularly when using automated systems. Other hatcheries have different problems including cost of disposal (average of $127.3/tonne), finding disposal sites, odour, high percentage of liquid, high water use needed to facilitate separation, vacuum system blockages, spillage (at hatchery and during transport), staff health issues, flies, noise and abrasiveness of the egg shell. Current disposal methods are land fill, composting, rendering and incineration. Hatchery wastewater is used for irrigation at 38.5% of surveyed hatcheries, and 15.4% of the hatcheries dispose waste water directly into the sewer. One hatchery used a waste water treatment system, one hatchery used a sewage/treatment system, and another hatchery disposed waste water into a lagoon. Most of the hatchery managers agreed that developing alternative methods to manage the hatchery waste is worth the effort. The average disposal cost is $1324/week for a hatchery producing 10.4 tonnes of hatchery waste/week at a disposal cost of $127.3/tonne. An emerging issue for hatcheries is the availability of sites where the hatchery waste can be disposed. There is also a need to minimise methane emissions to the environment from land fill sites. Therefore, cost efficient and environmentally friendly methods are required to treat hatchery waste to produce valuable products and reduce environmental concerns. Disposing hatchery waste to land fill will cause environmental problems such as releasing methane in the air and the possible spread of microbial contamination. Off the shelf digestion systems for purchase by hatcheries are not available and need to be built and designed by engineers specifically to the requirements of each hatchery. Separating hatchery waste into different components such as liquid, solid and shell waste to treat them separately is the most efficient method [1]. Separation methods include centrifuging, inclined screens, the use of a belt or filter press, flexible multi-layer filters and the use of a conveyor with upper and lower conveyor rollers to separate liquid and solid. The most effective method for treating organic waste including hatchery waste on site is to establish an anaerobic digester system. It is by far the most popular process used to treat organic wastes in all other organic waste industries. It has the advantage of being a high efficiency process and produces biogas which can be used for heating or generating power. The biosolids remain after the digester process which can be used a high quality fertiliser. Composting is another way to treat waste effectively, although it is less efficient than anaerobic digestion [1].
Anaerobic digestion is a complex biochemical process in which organic compounds are mineralized to biogas, primarily consisting of methane and carbon dioxide, through a series of reactions mediated by several groups of micro organisms in the absence of oxygen [2].
Anaerobic digestion techniques can help reduce the emission of greenhouse gasses by replacement of fossil fuels. Improvement in anaerobic digestion can be accomplished by multiple ways, some of which are optimisation of the process conditions, pretreatment of input effluent and increase of process temperature.
Wastewater (effluent) is not a pollutant necessarily but a nutrient resource which can be recycled using integrated farming practices.
A current major concern is environmental pollution from solid wastes and wastewaters from intensive animal farms and tertiary industries. The “waste”which provides income through producing a valuable product, in effect, becomes a “resource”. Nitrogen and phosphorus are resources and their bioavailability can be optimised through aerobic or anaerobic digestion processes. The process simply allows recycling the nutrient and water, prevents pollution and produces valuable end products [3].
There are different processes used for wastewater treatment e.g. conventional activated sludge and trickling filter methods, oxidation/waste stabilisation ponds, aerated lagoons and variation in anaerobic treatment systems [4]. However, while most of these are energy-based treatment processes, only a few of them lead to any resource recovery. In recent years a more developed process called the Up Flow Anaerobic Sludge Blanket (UASB) has been developed [5-7].
Wastewater treatment usually involves additional costs (e.g. energy usage). If the treatment itself produces income, prevents pollution and complies with the environmental standards, it increases the profitability and the sustainability of the industry [8]. While treating the organic waste in the sewage, aquaculture products (fish), aquatic plants and agricultural products can be produced. The introduction of aquaculture into the wastewater treatment industry to remove nutrients and release clean effluent has proved to be successful in many countries [9].
5. Conclusion
The most effective method for treating hatchery waste on site is to establish an anaerobic digester system. It is by far the most popular process used to treat organic wastes in all other organic waste industries. It has the advantage of being an efficient process and produces biogas which can be used for heating or generating power. The biosolids remain after the digester process, which can be used a high quality fertiliser.
Off the shelf digester systems for purchase by hatcheries are not available and need to be designed by engineers and built specifically to the requirements of each hatchery. Hatcheries disposing wastewater into lagoons could adopt the integrated biosystem approach to produce water suitable for irrigation and other potential products such as ornamental fish, a multi-billion industry worldwide. The ideal system in a hatchery would incorporate separation and handling equipment to separate waste into its various components for further treatment. This would save disposal costs, produce biogas to reduce power costs at plants and produce a range of value added products.
Acknowledgments
The authors are grateful for the funding provided by the Chicken Meat Program of the Rural Industries Research and Development Corporation of Australia to conduct the survey. We would also like to thank the hatchery managers in Australia for their participation in the survey.
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