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Cleaner Production Demonstration Project at Bonlac Foods, Stanhope

In 1994, Bonlac Foods participated in the Cleaner Production Demonstration Project, an initiative of the Environment Australia - Environment Protection Group (EPG). The Executive Summary of the demonstration project report is provided below. The full report can be accessed through the hyperlinks in the Table of Contents (also below). A further casestudy based on an initiative originally identified in the original casestudy, Anhydrous Milk Fat Serum Fat Recovery, is also documented comprehensively.

Background

Bonlac Foods is one of Australia's leading dairy companies and currently processes approximately 40 per cent of Victoria's milk supply. The company produces over 70 different manufactured products, which are exported globally to over 50 countries.

The company has 14 manufacturing facilities, 9 of which are located in Victoria.

Bonlac Foods has achieved a number of significant environmental outcomes in recent years, including:

Executive Summary

The Cleaner Production Demonstration Project (the Project) was an initiative of Environment Australia -The Environment Protection Group (EPG). The aim of the Project was to raise the awareness of Australian industry and actively promote cleaner production issues. This was to be achieved by conducting ten successful cleaner production demonstration projects in industry around Australia, documenting the benefits and experiences of the project, and publicising the results to wider industry. Dames & Moore, assisted by Energetics, were engaged as technical consultants on the project. The project commenced in June 1994, and ran for 27 months.

Bonlac Foods' Stanhope facility in Victoria was selected as one of the ten companies to participate in the project. This case study represents a record of progress of the Bonlac project, and any problems or lessons which may have been encountered. The case study demonstrates the application of Cleaner Production to the dairy foods processing industry.

Bonlac Foods, Australia's largest manufacturer of dairy products, is committed to producing high quality dairy products with minimal impacts to the environment. When producing cheese and milk powder, Bonlac is faced with the problem of preventing small particles of cheese entering its waste water drainage system. These particles represent a loss of product and add an unnecessary load onto the waste water treatment facility.

In addition, Bonlac must ensure that all process equipment, pipes and tanks are kept clean and free of unwanted micro-organisms. This is achieved with a periodic chemical flushing process called, Cleaning In Place (CIP), and involves the use of both alkaline solutions and acid detergents. These chemicals ultimately discharge to the waste water treatment facility and increase the load on the system.

The cleaner production demonstration projects that were initially identified were as follows:

Alternative CIP Cleaning Process/Solution

The use of Stabilon ® was expected to reduce the use of an acid cleaning solution in the dairy CIP process. It was also expected to reduce the total volume of waste water and phosphorous levels in the effluent being discharged to the waste water treatment facility. Change over to Stabilon®; detergent was found to reduce the cycle time of the CIP process, providing more time to produce cheese. This resulted in an income net benefit of about $310.00 per day.

Diversion of Waste water to Land Filtration

Some of the less contaminated waste water streams were to be diverted to a farm for spray irrigation thus reducing the biological and hydraulic load on the effluent treatment facility. The diversion to farm is limited to the drier months. Soil which is too wet cannot effectively handle the additional waste water.

Results of a ten day trial indicated a 30% reduction in the waste water volume discharged to the waste water treatment facility. The diversion will recommence on a regular basis in the next cheese production season.

Solids Screening, Cheese Room Waste water

Appreciable quantities of cheese solids are lost to the drain in the cheese room operations during normal production, daily wash down and the CIP process.

Bonlac aims to capture these solids and reduce the organic load on the waste water treatment facility. Two methods were proposed to deal with this issue. The first involves installing screens at the points where the large losses occur. The second method involves installing two large settling tanks in the whey room to capture cheese fines in the process rinse water. The impact of the project was to be assessed by monitoring the total suspended solids levels in waste water discharge from the cheese room.

Overall levels of suspended solids in the water was immediately noted as a results of the project implementation. The reduction was not as significant as expected but this is largely attributed to only one settling tank being commissioned. In addition, insufficient time was available to properly tune the tank to operate at optimum design conditions. This is believed to have reduced the effectiveness of the settling tank in removing the solids from in the waste water discharge. However, Bonlac will have both tanks operational and fully tuned for the next cheese production season. It is expected that the TSS level in the waste water discharge will show a significant reduction.

The total cost for the works to capture the cheese fine was about $30,500 The budget recovery of the fines was monitored by Bonlac Stanhope on a monthly basis. The recovery is expected to translate as $100,968 Therefore, the payback period for this project is less than 4 months.

Alternative Disposal of Soap Stock

Soap stock is a by-product of anhydrous milk fat production. It is basically a mixture of caustic soda and free fatty acids, and is approximately 5 % solids. It is normally disposed to landfill at a property owned by Bonlac. An opportunity was identified to sell the product to commercial soap manufacturers, however the natural composition of the soap stock was found to vary beyond the specifications imposed by the soap manufacturer and the project was postponed indefinitely.

A key lesson from this Cleaner Production demonstration project is that the process of compiling the environmental and process data in itself plays an important role in the identification of Cleaner Production initiatives. Other important lessons which emanated from demonstration project include the importance of commitment from management, ideas are encouraged in teams commissioned to assess specific parts of the operation, and that opportunities do not have to involve large capital costs.

Cleaner Production initiatives have been implemented at Bonlac Foods (Stanhope) with significant improvements. This has provided Bonlac with incentive for other Cleaner Production opportunities to be investigated and implemented.

1.0 Review of Bonlac Operations

Table of Contents

Executive Summary

1.0 Review of Bonlac Operations

2.0 Planning and Organisation of the Bonlac Foods Cleaner Production Project
2.1 Cleaner Production Approach used at Bonlac Foods
2.2 Cleaner Production Opportunities
2.2. 1 CIP Chemicals Change Over
2.2.2 Diversion of Waste Water to Farmland
2.2.3 Solids Screening from Cheese Room Waste Water
2.2.4 Alternative Disposal of Soap Stock

Product processing
3.0 Cleaner Production Initiatives
3.1 CIP Chemicals Changeover
3.1.1 Project Evaluation and Implementation
3.1.2 Results
3.2 Diversion of Waste Water to Farm Irrigation
3.2.1 Project Evaluation
3.2.2 Project Implementation
3.2.3 Results
3.3 Solids Screening from Cheese Room Waste Water
3.3.1 Project Evaluation
3.3.2 Project Implementation
3.3.3 Results
3.4 Alternative Disposal of Soap Stock
3.4.1 Project Evaluation
3.4.2 Project Implementation
3.4.3 Results

4.0 Review of Project

5.0 Concluding Remarks

6.0 Bonlac Foods Perspective

List of Tables

Table 1 Daily marginal costs associated with changes over to Stabilon®

List of Figures

Figure 1 Volume of waste water discharge to the waste water treatment facility per tonne of cheese produced for both the 1995/1996 season and the 1994/1995 season (kL of waste water/tonne of cheese)
Figure 2 Tonne of cheese produced per kilolitre of milk intake for both the 1995/1996 season and the 1994/1995 season (tonne of cheese/kL of milk intake).
Figure 3 Volume of effluent discharged to the waste water treatment facility before, during and after the diversion of low ionic waste streams to farmland for irrigation.
Figure 4 Volume of effluent discharged to the waste water treatment facility per tonne of cheese produced, before, during and after the diversion of low ionic waste streams to farmland for irrigation.
Figure 5 Total suspended solids in the waste water discharge stream per tonne of cheese produced for the 1995/1996 cheese production season.
Figure 6 TSS in waste water per tonne of cheese produced 1995/1996 season (screens installed November 1995)

Further Developments - Anhydrous Milk Fat: Serum Fat Recovery

It was identified in the original demonstration project that serum fat could be advantageously recovered from AMF soap stock effluent at Bonlac's Stanhope plant. In 1998, this project was implemented with the following benefits achieved: product waste reduced by 4%, recovery of a saleable by-product, significant reduction in waste management costs, plant rationalisation and improved effluent quality.

The Process

One of the products manufactured by Bonlac Foods is Anhydrous Milk Fat (AMF). Historically AMF was manufactured at the Stanhope (from cream) and Cobden (from cream and butter) plants.

AMF is a product that consists of pure milk fat of at least 99.9% purity. The basic process for production of AMF from cream is shown in Figure 1.

Figure 1: AMF Flow Sheet
Production of Anhydrous Milk Fat flow sheet

Refining of the AMF is required to reduce the level of free fatty acids in the final product. High levels of free fatty acids reduce product quality and increase the risk of product spoilage through oxidation (rancidity).

Caustic soda solution (8-10% caustic) is applied to the serum, which then washes or reacts with the free fatty acid chain to release and separate the free fatty acid into the soap stock stream. The basis of this process is shown in Figure 2.

The concentration of the caustic solution depends on the free fatty acid content of the raw material.

Figure 2: Free Fatty Acid Neutralisation

Free Fatty Acid Neutralisation flow sheet

A significant disadvantage with this process is that it produces an effluent stream (soap stock) that has a high organic load and hence high chemical oxygen demand (COD).

For example, the Stanhope plant produced approximately 17,000 litres per day of soap stock with a COD load varying from 1.5 - 4.0 tonnes per day. As the on-site treatment plant was designed for a loading of 8 tonnes COD per day, the discharge of the soap stock effluent represented a significant proportion of the total COD load, even though it was only a very minor flow in volume terms (approximately 0.5%). Significant overloading of the treatment system resulted, with out-of-specification effluent and off-site odours being a common occurrence. In order to overcome this problem, Bonlac Foods developed a land disposal technique for the soap stock solution. While this represented an acceptable waste management solution it also had a high cost associated with it ($160,000 - $170,000 per annum).

Bonlac Foods Cobden plant also experienced problems with the soap stock effluent which contributed 1.6-3.2 tonnes per day of COD to the site effluent, which was discharged to sewer after on-site treatment in an Induced Air Flotation cell.

Cleaner Production Initiative

The cleaner production initiative implemented by Bonlac Foods comprised of two elements;

The process for recovery of fat from the soap stock effluent involved cracking of the emulsion using nitric acid and then recovery of fat in a centrifugal separator. The recovered fat is sold to a stock feed manufacturer while the water phase from the separator is clean enough to be discharged to the site effluent treatment system (refer to Figure 3).

The soap stock effluent is now directed to a holding tank and regularly (twice per day) processed through the separator. The recovered fat is stored in a modified milk tanker, pending pickup by the stock feed manufacturer.

A key part of the project was the rationalisation of AMF production to Stanhope. This has avoided the cost of duplicating the recovery equipment at Cobden and reduced treatment costs.

Cream and butter effluent from Cobden is now transported to Stanhope. The fact that Cobden now has to pay transport costs for its butter effluent has provided a direct incentive to reduce wastage in Cobden's butter room (there was no incentive before because all butter waste could be used as feed stock for Cobden's own AMF plant). Excess cream from other plants is also sent to Stanhope for processing.

Advantages of the Process

The project has a direct economic benefit as the recovered fat is sold as a by-product. In addition, the cost and management problems with land disposal have been substantially reduced. While the cost of rationalising AMF production to Stanhope was significant, it has been offset by reduced effluent costs and improved effluent quality at Cobden. Product waste has been reduced from 6% to between 1-2%. A summary of the costs and savings is presented in Table 1 below:

Table 1

Project Costs and Savings Summary

Initiative Cost Savings, p.a.
AMF Fat Recovery - Stanhope $28,325  
Rationalisation - Cobden $245,000  
Acid costs unknown  
Transportation $6,500  
Sale of recovered fat   $21,000
Reduced land disposal costs - Stanhope   $170,000
Reduced Effluent costs - Cobden   $70,000
Improved Butter Room efficiency - Cobden   $60,000
Frozen Butter vs Butter Oil for production   $200,000
TOTAL $279,825 $521,000
PAYBACK   0.5 yrs

Cleaner Production Incentive

The cleaner production principle is inherent to corporate culture at Bonlac Foods, as the company recognises the market benefits of "beyond compliance" initiatives. The high costs associated with managing the soap stock effluent provided an additional incentive for this project.

Bonlac received a grant under the Victorian EPA's Cleaner Production Partnerships Program to assist with the implementation of the AMF Serum Fat Recovery Project.

Barriers

The main barriers to implementing this project included:

The separator that is used to recover the fat from soap stock is shared with the whey processing facility. This shared arrangement requires that good production scheduling between the AMF and whey production units is essential in order to ensure the equipment is available for each demand when required. This potential operational problem has been overcome by a strong corporate culture that values and recognises the importance of involving all levels of the company's employees.

Contact

Jim Steel
Group Environmental Coordinator
Bonlac Foods Limited
PO Box 21
Stanhope Vic 3623
Ph: (03) 5857 2505
Fax: (03) 5857 2301
Email: jim.steel@bonlac.com.au 

Implementation: 1996
Further initiatives: 1998
Original casestudy initially prepared: 1996 by Dames and Moore and Energetics for Environment Australia as part of the Cleaner Production Demonstration Project
Anhydrous Milk Fat casestudy initially prepared: 1999 by the Australian Centre for Cleaner Production

ACCP

Last modified: June 2001