The Dairy Processing Industry In Mauritius Environmental Sciences Essay

Nowadays, the dairy industry is categorized into two distinct production areas. The primary production of milk is principally on farms, whereby cows and other animals, such as goats, sheep, and among others, are bred for the production of milk for human consumption. The processing of milk has for main objective of extending its saleable life and keeping quality. This can be achieved by a number of food transformation and preservation techniques. Milk can be heat treated, can be prepared variously in a dehydrated form like butter and milk powder, thirdly by freezing, for instance, ice cream and other frozen desserts and finally by fermentation like yoghurt, cheese, ghee, kefir and among others.

1.1.1 Profile of the dairy processing industry in Mauritius

Mauritius has one of the strongest economies in Africa, with a per capita GDP close to U$3,900. Its economy has been heightened greatly over the past 15 years and the main sectors, which have driven the performance, were the textile, tourism and sugar industry. However, studies prepared by the Imani Development Consultants (2004), for the Regional Agricultural Trade Expansion Support Program, have demonstrated that the local dairy is a very small sector with only about 5000 dairy cows, producing about 4 million litres of milk, which represent only 5% of the total requirements. Hence, Mauritius does not have the resources and capacity to produce milk efficiently. About 1 million litres of the milk produced, through reconstitution from powder milk, is marketed as pasteurised milk by the Agricultural Marketing Board and other dairy industries.

Likewise the Imani Development Consultants (2004) added that the consumption trend of most dairy products has considerably increased over the past 5 years from 12,800 tons in 1995 to 22,000 tons in the year 2002. This trend is expected to continue with the rising standard of living of the Mauritian population. There is now a growing market for UHT milk despite the fact that milk powder is widely preferred by the population. Australia and New Zealand remain the principal suppliers of dairy products to Mauritius. There are various renowned dairy products brands in most supermarkets and retail shops.

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Although Mauritius is not a milk producing country, it has three main dairy products manufacturers, namely Maurilait Ltd., INNODIS Ltd., and Laiterie de Curepipe, which are producing mainly yoghurt, ice cream, sterilised milk and flavoured milk, using imported raw materials.

1.1.1.1 INNODIS Limited

INNODIS Limited is one of the main food and grocery distributors and producers in Mauritius. It is a large company engaged in different sectors, ranging from poultry, rice milling, consumer goods, frozen foods, dairy production and among others. The company has invested profusely to bring over a high performance in quality and reliability of its products and this has nowadays led to an annual turnover of Rs 2.5 billion (Anon2, 2010).

The dairy Plant of INNODIS Ltd was set up since 1952, with an Ice Cream business activity, manufacturing Nestle products under the brand name Dairymaid. It has nowadays developed close partnerships with South African licenses and has integrated other production lines of yoghurt, nectars, and sterilized milks under the brand name of DairyVale, Ceres, Twin Cows and Ole respectively. Ice Cream production includes 45% of the total production, followed by 30% of yoghurt production and a remaining of 25% for nectars and sterilized milk (pers. comm., 2010).

The dairy plant of INNODIS Ltd has adopted a food safety management system, for instance, the HACCP Codex Alimentarius Standards and adheres to the Nestle and Ceres Standards in order to keep up consistency in quality of products and work within the factory. The installed capacity of the dairy processing plant is 2million Litres of milk per year and is presently being used at 90% of its capacity milk (pers. comm., 2010).

1.2 Dairy Processing Waste

1.2.1 Water consumption

Water is the principal raw material and cleaning constituent in the food processing sector. In the dairy processing industry, substantial volumes of water is used for cleaning equipment and work areas to maintain the hygienic conditions, in cooling departments like in cooling towers and in energy production for example in boilers. Water also accounts for a large proportion as raw material in the reconstitution of milk powders for the production of liquid milk, yoghurt, ice cream, butter, cheese and among others.

Rates of water consumption can vary significantly based on the scale and capacity of the plant and type of processing, whether batch or continuous processes. The type of mix being generated, the methods and cleaning equipments being in use as well as considering the human factor with inference to the practices of the operatives on the production departments can also affect drastically the consumption of water in the dairy processing.

A typical range for water consumption in reasonably efficient plants is 1.3-2.5 Litres water/Kg of milk intake (UNEP, 2000). In most parts of the world, fresh water is becoming scarcer with the evolution of climatic phenomenon like droughts and ‘el lino’ and as such, the cost of water is rising and the true environmental costs of its supply are being taken into consideration. Water has thus become an increasingly valuable commodity and its efficient use is being now emphasized on drastically.

There can be effective water management strategies for reducing water consumption and this can involve technological solutions or equipment upgrading. Moreover, a dairy plant waste load can be curbed down considerably by monitoring the amount of water used and reducing the amount of product lost into the effluent. This control will all depends upon the machine set-up and the operator’s practices. Stopping wastage at its source will therefore be less costly and more practical than end-of-pipe waste treatment. By doing so, the water expenditure can be declined up to 0.8-1.0 Litres water/kg of milk intake (UNEP, 2000). Techniques described in the publication made by the UNEP in 2000 are well defined accordingly:

Continuous rather than batch processing is better to be introduced as it prevents frequent cleaning.

Automated cleaning-in-place (CIP) systems allow less dismantling of equipments and therefore less use of water.

Flow meters are placed at different spots of the processing line to control and monitor the flow of water for manual cleaning procedures.

High pressure rather than high volume is preferred for cleaning surfaces. Compressed air can be used also.

Re-circulating or re-using clean water which may have been used for rinsing to other activities which is not a commodity for cleaning and processing.

1.2.2 Waste water discharge

Water discharges are produced mainly in the dairy industry by processing operations but also by clean water which are released from cooling water and steam and evaporator condensates. This discharge ultimately becomes the effluent, which contains predominantly milk and milk constituents which have been lost from the process. According to studies made by the UNEP (2004), milk loss can be as high as 3-4% with the main source of loss being residues which remain on the internal surfaces of vessels and pipes, draining of mix from machines before filling, spills during emptying tanks and overflowing of vats or hoppers. Likewise, the organic load of the effluent varies greatly with the type of cleaning practices being applied. Batch processes will normally require a greater and frequent cleaning. Thus, the COD level can reach up to about 8 Kg/m3 milk intake.

1.2.2.1 Characteristics of waste water and their impacts on the environment

The characteristics of the waste water generally vary from different types of dairy products owing to their different constituents and ways of processing.

Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD)

Organic components which is within the dairy waste water consists of mainly proteins like whey and caseins, lactose and fat and these can affect the ecosystem depending on their solubility and biodegradability to lead further to an organic pollution of the environment. These can be determined on a laboratory scale by using the BOD and COD factor. Microorganisms, specifically bacteria, require and degrade organic nutrients for their survival and simultaneously they consume oxygen. The oxygen used can be measures and the BOD and COD.

BOD is measured as the amount of oxygen that is consumed by bacteria while decomposing waste over an incubation period of 5 days at a temperature of 20 °C. The COD can be enumerated as the oxygen equivalent for the decomposition of organic matter and oxidation of inorganic chemical such as ammonia and nitrite. One litre of whole milk is equivalent to approximately 110 Kg BOD5 or 210 Kg COD (UNEP, 2000). Moreover, mandatory regulations from the Environment Protection Act 2002 (EPA) have shown that there should be a minimum of 120 mg/ L of COD and 40mg/ L of BOD (Appendix 1). Hence, it is a must to abide by the legislation as prescribed.

Whey loss

One major contributing element to a dairy plant’s effluent load is the cumulative presence of high concentration of milk, which contains a large proportion of the salty whey. Whey is also added as an inclusion the mix composition of ice cream. Hence, with these losses occurring during pipe work is uncoupled during tank transfers or equipment is being rinse, there can be greater release of the whey concentrates and other isolates like lactose and caseins to the effluent system. The main concern with whey loss is that it increases the BOD level of the effluent system. Hence, it is a must that green manufacturing practices are taken so that milk or any other dairy products and intermediates are not drained out into the effluent system.

Other measures currently being used now is that whey, being used as an additive in certain dairy products, can be re-processed from the dairy industry waste. An investigation carried out in 11 dairy plants by Ostojic and others (2005) have demonstrated that 78.5% of whey, in the form of milk, has been discharged into the waste water contributing to the organic pollution of the environment. This contamination can therefore be prevented by transforming the whey into food, animal feed and pharmaceuticals. Process of vacuum concentration and filtration needs to be performed to obtain the whey proteins.

Table of waste water characterisitics -still compiling normative data

1.2.2.2 Waste Water Treatment Options

Absorption Ponds

Absorption ponds are popular for dairy wastewater disposal but as with the ridge and furrow systems they are not constructed as much today because of concern about compliance with environmental laws. Typically absorption ponds were used by the smaller dairies where there is small wastewater volume. As these small dairy plants have closed, many of these absorption ponds have been taken out of service. Absorption ponds can still be used; however, it requires internal treatment of the waste water. Activated enzymes can be added to degrade the organic waste. Then, the waste water is collected by waste water carries to be further treated by the public or municipal treatment plant.

Biological Tower

This could be considered a modern filter where wastewater is pumped down over a support covered with a media which allows microbiological growth. The microorganisms or bacteria consumes the organic waste of the wastewater as food and eventually sloughs off for collection into a clarifier. The biological tower is typically used as an initial treatment unit before sending the effluent for full treatment by the public authority.

Activated Sludge

Activated sludge is a conventional process for treating dairy industrie’s waste water using air and a biological mixture composed of bacteria and protozoan. Air or oxygen is introduced in a primary treated effluent combined with the organisms used to develop the biological floc. In this way, organic matters like biological constituents of milk, ammonia, nitrates and phosphates are removed and converted into carbon dioxide and nitrogen eventually. The effluent is the clarified and is collected for disposal. The sludge or waste mud produced can be also treated. A typical activated sludge system can be shown in the figure below:

Figure 1 – An Activated Sludge Process

(Beychok, M., 2007)

Aerated Lagoons

Aerated lagoons have been a common method of wastewater treatment for dairy plants that directly discharge to surface water like rivers and sea. Generally these systems are several large ponds connected in series with floating surface aerators or submerged air diffusers.

1.2.2.3 Treatment of waste water in Mauritius

The effluent from the dairy plants should normally be treated at some extent on the site or sent to the local treatment systems. For instance, in Mauritius, the ‘St Martin’ waste water treatment plant treats the wastewater from the Upper Plaines Wilhems as well as the regions of Lower Plaines Wilhems. The plant has a designed capacity of 69,000 m3 per day. The treatments consists of a primary step whereby there is screening of the effluent. Then, the secondary treatment constitutes of disintegration and removal of grit (Institute for Environment and Legal Studies, 2010). The final treatment phase is disinfection using ultra violet technology. Currently, the St Martin treatment plant has a capacity of approximately 25,000-30,000 m3 per day and this treated water is used mostly for irrigation purposes (Anon, 2007).

1.2.3 Energy consumption

According to research carried out by the United Nations Environmental Program (2000), about 80% of a dairy plant’s energy is catered by the combustion of fossil fuels (coal, natural oil or gas) in a boiler system to generate steam and hot water for evaporative and heating processes. The remaining 20% is met by the public electricity for running electric motors, refrigeration and lighting.

The age and capacity of a plant, the level of technology and automation and the number of products being manufactured, largely affect the energy consumption of a dairy industry. Processes, which involve intensive heating, concentration and drying, for instance spray-dried of milk powder, entail much energy. Nevertheless, milk, which needs partial heat treatment and packaging, requires less energy. A typical range for energy consumption in plants processing milk is 0.5-1.2 MJ/kg of milk intake (UNEP, 2000).

A good energy management program will identify uses of energy for a dairy factory and can highlight areas for improvement. Substantial savings of energy can be easily made with no investment of capital, via simple housekeeping and green productivity practices. Energy savings of up to 25% are possible through switch-off programs and the fine tuning of existing processes, and an additional 20% can be saved through the use of more energy-efficient equipment and heat recovery systems. By doing so, energy consumption for the processing of milk can be reduced to as low as 0.3 MJ/kg of milk intake (UNEP, 2000).

Some energy-saving initiatives are listed below, and these can represent a best practice for the dairy industry.

An energy management circle can be set-up within the dairy plant to identify issues and monitor them.

Energy-efficient lightning can be installed.

Efficient refrigeration compressors can also be set-up.

There should be regular tagging and measurement of energy consumption of each machine and this can easily help to indentify bottle-necks within the system.

Steam and air leaks and other pipelines should be repaired as soon detected.

1.2.3.1 Greenhouses Gases (GHGs)

With the profuse combustion of fossil fuels (coal, kerosene, fuel oil, diesel oil, etc.) nowadays to make power to run industrial machines, heat water and operate distribution vehicles, a potential amount of GHGs is being evolved in the atmosphere. leading to the so-called drastic environmental effect, Global Warming. According to the IPPC (1997), water vapour is the most important GHG, contributing 36-70% to global warming; carbon dioxide (CO2) and methane add to 9-26% and 4-9% respectively, while ozone contributes 3-7%. As related to fossil fuel combustion, CO2, methane and nitrous oxide are the most important GHGs.

The problem with GHGs is that over the last few years the concentration of GHGs in the atmosphere, especially CO2, has greatly increased. Greenhouse gases are like a blanket around the earth, making the atmosphere warmer. They absorb the heat from the earth, and re-radiate it to space, and the other half goes right back to the earth’s surface. Thus, with the slight increase in temperature in the atmosphere, the circulation patterns of the ocean and wind currents are altered causing climatic changes.

1.2.4 Solid wastes and packaging

Dairy products such as milk and yoghurt are typically packed in plastic-lined paperboard cartons known also as tetrapak, High density polyethene (HDPE) cups, plastic pouches or reusable glass bottles. Moreover, ice cream is known to be filled in HDPE tubs and cups as well as paper-lined cones. Other products, such as butter and cheese, are wrapped in foil, plastic film or small plastic containers. Milk powders are commonly packaged in multi-layer kraft paper sacs or tinned steel cans, and some other products, such as condensed milks, are commonly packed in cans. Breakages and packaging mistakes cannot be totally avoided. Improperly packaged dairy product can often be returned for reprocessing or recycling. However, the packaging material is generally discarded. At INNODIS Dairy Plant, it is known that bottles used for sterilized milk can be recycled, yet HDPE cups and tubs remain unprocessed and disposed at ‘Mare Chicose’ Land Fill (Pers. Comm., 2010).

1.3 Life Cycle Assessment (LCA)

Life cycle thinking is an essential element to sustainable development. It is about going beyond the traditional focus on production site and manufacturing processes so to include the environmental, social, and economic impact of a product or a process over its entire life cycle [United Nations Environment Program (UNEP), 2007]. The producer has therefore for responsibility for their products from cradle to grave and should aim at developing products, which have enhanced performance in all stages of the product life cycle. The life cycle management tools expand from Cleaner Production Assessment (CPA), Cumulative Energy Requirements Analysis (CEPA), and Life Cycle Costing (LCC) to Life Cycle Assessment (LCA). All these techniques helps in the implementation of the green concept, namely the “6 Re Philosophy”, which are defined by UNEP (2007) furthermore below.

Figure 2 – “6 Re Philosophy” throughout the product lifecycle

(UNEP, 2007)

1.3.1 Definition of LCA

Life Cycle Assessment is a methodological technique that applies life cycle thinking in quantitative way on the environmental analysis of activities associated to products, processes or services. A holistic focus will be placed on products/ services by assessing the upstream to downstream activities of their process flow. Therefore, LCA determines the potential environmental sequentiae of products, processes or services, throughout its life cycle, i.e., from raw material acquirement to production, usage, and finally disposal. This is the so-called cradle to grave approach (Environment, Health and Safety Committee, 2005).

The Society for Environmental Toxicology and Chemistry (SETAC) (Boudouropoulos et al., 1999), has well defined the Life Cycle Assessment as an important “environmental management tool used to evaluate environmental burdens associated with a product, process or an activity, by identifying and quantifying energy and materials used and wastes released to the environment, to assess the impact of those energy and materials uses and releases on the environment, and evaluate and implement opportunities to affect environmental improvements. The assessment includes the entire life cycle of the product, processes, or activity, encompassing extraction and processing of raw materials, manufacturing, transportation and distribution, use/re-use/maintenance, recycling and final disposal”.

Hence, in all activities implicated during the life cycle of a product or service, resources are consumed from the environment and wastes are generated back into the environment. This can be illustrated in the schematic diagram below.

Figure 3 – The life cycle of a product with the input of resources and output of waste

(Chen, 2008)

LCA has its roots in the 1960s, when the scientists who became concerned about the rapid depletion of fossil fuels, established it as a move towards understanding the consequences of energy consumption. The concept of environmental LCA was further developed from the idea of comprehensive environmental assessments of products, which was conceived in Europe and in the USA in the late 1960’s and early 1970’s (Hunt, 1998). It is a relatively new and cutting-edge environmental decision support tool and young discipline, as it provides quantitative environmental and energy data on products and processes (Mwangome, 2009). Although still under development, LCA has been standardised by the International Standardisation Organisation (ISO) as an element in the ISO 14000 series. The principles and guidelines of the LCA are found within the standards of the ISO 14040; the ISO 14041 to ISO 14043 describes the methodology of the LCA process.

1.3.2 Principles of the LCA

Generally, an inventory of relevant inputs of resources, like water, raw materials including packages, energy and fuels, and outputs of detrimental wastes such as carbon dioxide, nitrogen dioxide, solid wastes, nitrates and phosphates, released to the environment, are identified, quantified and compiled. Their potential burdens on the environment and ecosystem are determined and evaluated, and immediate measures and practices for improvements specific to the objectives of the assessment are found and assessed for use. Through such a systematic overview and perspective, the shifting of a potential environmental burden between life cycle stages or individual processes can be detected and possibly avoided.

To be able to carry out the methodology of the LCA, a functional unit of the product should be taken and it is defined by the reference unit of the product being in study, for instance 1L of bottled water can be evaluated from cradle to grave. The sum of each impact at each specific step or stage of the process flow help to provide an assessment score to determine the hotspots of the entire life cycle of the process. Therefore, measures to mitigate environmental impact have to be prioritized and emphasized on the hotspots.

1.3.3 Life Cycle Assessment Methodology

The life cycle assessment occurs in four main phases which fully explains the different steps and order for it to be carried out.

Phase 1 – Goal and Scope Definition

The first stage is specifically the planning which implies defining and describing the product, activity, and process to be analyzed. The aims of the assessment are established and the life cycle steps and impact categories like energy or water use are identified and reviewed.

Phase 2 – Life cycle inventory analysis

This stage involves identifying and quantifying inputs like energy, water, materials and land usage and the outputs releases to the environment like air emissions, solid waste, water discharge, energy lost during the entire lifecycle.

Phase 3 – Life cycle impact assessment

At this phase, the consequences of the material consumption and environment releases to human health and the eco-system, like acidification, global warming and ozone depletion are evaluated.

Table : Description of some lifecycle impact categories (Narayanaswamy et al., 2002)

Lifecycle Impact Categories

Description

Global Warming

The release of carbon dioxide and other greenhouse gases (GHGs) have a warming effect on the atmosphere is known as global warming.

Acidification

Acid gases such as sulphur dioxide and nitrogen dioxide have the ability to produce acid rains when condensed and this therefore increases the acidity of the land and soil and cause even damages of buildings and other infrastructures.

Eutrophication

Releases of phosphates and nitrates in the underground water or in rivers can cause algae to bloom out, endangering the freshwater ecosystem.

Human toxicity

Some pollutants such as dioxine or dichlorobenzene can be absorbed in food stuffs and cause the death or disability of humans.

Dryland salinity

Clearing of native lands can cause the increase of seawater logging catchments areas rising the salinity of the land.

Phase 4 – Life cycle Interpretation

The findings from the inventory analysis and impact assessment are combined together so as to reach conclusions and recommendations which are consistent with the goal and scope of the assessment. The most significant impact and hotspot in the life cycle of the product, process or activity are simultaneously identified.

1.3.4 Applications of Life Cycle Analysis

Life cycle assessment has had a wide application in the dairy industry and has started from farm to fork. In dairy farming, LCA has been used specifically in the quantification of greenhouse gases (GHGs), particularly in countries like New Zealand, Australia, Canada and Netherlands. Moreover, pertaining to milk processing activities like butter, yoghurt, sterilized and pasteurized milk, spray-dried milk, ice cream and among others, studies have not been done at a scientific level but also by reputated international industries, such as Unilever and Nestlé. The aim of these multi-national corporations is to mitigate their misuse of resources and pollution problems and have noticed several positive economic and environmental outcomes (Narayanasawmy et al., 2002).

It has been utilized in different formats. Many companies have used LCA as for establishing an eco-labelling scheme and therefore communicating about the environmental aspects about a particular product or service to consumers and stakeholders. Likewise, it is a useful tool to develop business strategies and policies and amplify the market shares. When combined with strategic decision models, LCA can be applied as an important supporting tool for business managers. Moreover, Life Cycle Assessment can be applied as a product and process improvement and design and thus allowing companies to comply with their local environmental regulations and laws.

1.3.4.1 International Studies based on LCA

A life cycle assessment was applied to the dairy industry in Mainland Portugal in 2005. The objective of the research was to evaluate the milk production and agriculture practices using the LCA. The goal of the LCA also consisted of identifying the relative contribution of each one of the different cow milk products, for instance, milk, yoghurt and curd cheese (Castanheira et al., 2005). The functional unit was 1L of raw milk. The boundary of the lifecycle flow was at raw milk processing, whereby packing and delivery to consumer were not considered. In the inventory analysis stage, the impact categories considered were mainly global warming, followed by photochemical oxidation, eutrophication and acidification.

Results have shown that the production of milk for consumption has the greatest consequences on the environment due to 49% global warming, 51% acidification and 57% eutrophication with 60% release of ammonia (NH3) and methane (CH4). In the milk production process meant for consumption, there was also a great impact from COD and nitrates, which has been seen as the main source of contamination of underground rivers. As from the curd cheese production, there was high emission of carbon dioxide, which is normally the principal contributing factor of GHGs in Portugal. This is owing to the high consumption of different forms of energy during the milk transformation to cheese (Castanheira et al., 2005). Yoghurt production had the least burden on the environmental in the Mainland Portugal with only 6% contribution of COD to waterlines. In addition, it was seen that most burdens are found at the raw milk production in the lifecycles of all milk for consumption, cheese and yoghurt flows.

Another study was performed in Italy by the ENEA (Italian Agency for new Technology, Energy and the Environment) and ERVET (Regional Agency for the Development of Emilia-Romagna), whereby the whole lifecycle of butter production was investigated (Masoni et al., 1998). The main objective of the study was to stress on the difficulties underwent by the Small and Medium Enterprises (SMEs) and try to establish a simpler methodology for LCA. Optimization or resources like water, energy and reducing wastes in terms of solid wastes, emissions of GHGs, and contamination of water were also focused. The functional taken was 5Kg butter delivered in 250g lot, under two alternative primary packaging, one by polyethene coupled with paper and secondly, aluminum foil integrated with a waxed greaseproof paper. The steps evaluated were from cream production to post-consumer waste management, using the Simapro software.

The sensitivity analysis conducted by Masoni and others (1998) for polyethene packaged butter revealed less accurate data can be used for most ancillary material processes, without impairing the overall inventory results. For instance, it was found that about 80% of water and 55% of energy were wasted at the raw material stage, with a total emission of approximately 55% CO2 and 50% NO2, and released of 53% of solid waste and heavy metals in waters. The emissions and heavy metal contamination were greater at the butter production compared to raw material processing, distribution and waste management. The solid wastes disposal was however drastic during the raw material processing. Moreover, the LCA study has not been completed for the cheese in aluminium packaging. It has been finally observed that a shortage of resources like capital, technological levels and awareness to environmental management can be limitations for an approach towards LCA as a decision-making tool for SMEs.

Whilst investigating the environmental impacts of the LCA in the Kenya, Mwangome (2009) has restricted her study to the energy consumption only. The importance of the research was upon aiming the operation efficiency based on the size of the studied dairy companies against the transportation process in the chain. The functional unit was allocated to 1Kg of processed milk. The LCA methodology was utilized to investigate the energy balances between inputs and outputs and from data obtained the environmental consequences were processed as carbon dioxide. The farming stage was observed to be the hot spot with the most consumed energy compared to the steps in the life cycle. It was therefore seen that Diesel was the main element contributing to the high emission of CO2, though wood and electricity were also a commodity for energy provision to dairy plants. Hence, this observation has helped to find measures to curb down the use of fuels and therefore bringing up eco-efficiency within food supply chains.

Likewise, Netherlands is known to be a principal producer of milk for ready use. Observations have been made that the emissions of greenhouse gases and c