AUTHOR: J. B. Phillips, M. A. Hindawi, A. Phillips and R. V. Bailey
TITLE: Multimedia--Managing Effluent from the Food Processing Industry
SOURCE: Pollution Engineering 32 no10 O 2000
Wastes generated by the food processing industry, like chemical plant wastes, generally are composed of complex mixtures of organic and inorganic compounds. Moreover, as in the case of chemical processors, the food industry usually relies on the ability of publicly owned
treatment works (POTWs) to accept its wastewater.
But because of the acidic or basic nature of many food processing wastes, POTWs enforce limits on biochemical oxygen demand (BOD) and pH levels. This column examines wastewater effluent from an orange juice processing operation, and compares two approaches to treating such
effluent.
O.J. WASTE CHARACTERISTICS
Waste from an orange juice manufacturing operation generally contains significant quantities of citric acid, as one might expect.
Citric acid is important biochemically for the conversion of nearly all foodstuffs to energy. [1] Biochemists refer to the citric acid cycle, the Krebs cycle or the tricarboxylic acid cycle -- these are one and the same. They all refer to the catabolism of two-carbon units of carbohydrates, fats and proteins in a process mediated by citric acid.[2] Orange juice consists of an aqueous solution of citric acid at a pH of approximately 2.0. Chemically speaking, part of citric acid's interesting behavior is because of its three acid moieties, and the
relative ease with which each can be removed and added back into the remainder of the molecule. These are the principal reactions -- along with standard acid-base reactions, oxidation-reduction reactions and hydration/dehydration reactions -- that are characteristic of the Krebs cycle.
TRADITIONAL TREATMENT
It is commonplace for wastewater containing citric acid to be "treated" simply through the addition of a basic substance, such as ammonia. This has two major, unpleasant effects: * Although the ammonia neutralizes the citrate ion, this is nothing more than an acid-base reaction. All of the citrate remains chemically unchanged.
* If ammonia is added to an acidic stream, there will be an
exothermic reaction due in part to the acid-base reactions.[3] vaporizing some of the ammonia. This ammonia must be treated prior to atmospheric release.[4]Unfortunately, this approach became routine because local POTWs could deal with the excess citric acid, and there was a lack of awareness about the potential hazards associated with ammonia releases.
Another factor was the easy availability of ammonia, which was present at low cost and on-site at many facilities. When much of this technology was implemented in the 1950s, environmental concerns were of relatively low importance. Even when stricter environmental regulations took effect
in the 1990s, the old technology was, by and large, grandfathered in.
A MULTIMEDIA APPROACH
More recently, it was proposed that citrate could be separated out of the wastewater and sold or used for another purpose. Because the citric acid already is in the acidified state (as opposed to sodium citrate, or some other basic salt of citrate), liquid-liquid extraction
would be a logical approach.[5] A non-polar solvent, such as diethyl ether or methylene chloride, would readily dissolve the citric acid, and permit easy recovery of the citric acid following separation from the aqueous phase. For example, addition of a strong base -- such as sodium
hydroxide, commonly known as "caustic soda" -- would cause the citric acid to form sodium citrate, which is much less soluble in non-polar solvents. A separate operation, such as filtering or distillation, then would allow recovery of the citrate (for reuse) and the solvent (for recycling).
Depending on the requirements of the local POTW, some or much of the citric acid in the wastewater might require biotreatment prior to discharge from an industrial food processing facility. Effluent from ammonia neutralization would be expected to be characterized primarily by significantly higher citric acid concentrations. It therefore would need a greater amount of predischarge treatment, using either biotreatment or another technology to reduce BOD levels, than would liquid-liquid extraction. Moreover, the old method generates a waste gas stream that contains a noteworthy level of ammonia. By contrast, the
citric acid is contained entirely in a liquid phase in the liquid-liquid process.
The recovery of nearly pure citric acid, which can be reused or sold, is attractive not only from a multimedia perspective, but also from a materials management point of view. Clearly, keeping all of the wastes in a liquid medium is consistent with principles of multimedia pollution engineering. Moreover, recovery of wastes in a recyclable form is preferable to waste treatment or disposal, and is consistent with the U.S. Environmental Protection Agency's (EPA) hierarchy of pollution prevention methodologies.[6]
SOLVENT RECOVERY METHODS
To recover and recycle the solvent used for extraction, it might be possible to simply add a base such as caustic soda to the stream following extraction, thereby converting the citric acid to a citrate salt. Naturally, addition of two equivalents of sodium hydroxide would result in the ionization of two carboxylic acid groups on each citric
acid molecule, and the formation of disodium citrate. In any case, the sodium salt (or disodium or trisodium salt) would be expected to be significantly less soluble in a non-polar organic solvent such as the aforementioned methylene chloride or diethyl ether, and likely would precipitate out of solution.
An alternative method distills the solvent out of the solvent/citric acid mixture at the upper end of a distillation column, with the citric acid/citrate salt remaining in the bottoms. If a highly volatile solvent
such as diethyl ether or methylene chloride were used in the extraction, then the energy requirements for distillation would be minimal, because both solvents boil at slightly higher than room temperature. However,
the explosiveness of diethyl ether would need to be considered.
CONCLUSION
Multimedia pollution engineering principles can be applied to the handling of wastes from food processing operations. Liquid-liquid extraction can be an effective means to separate one component from a complex mixture. A properly designed process allows recycling of both
the extracting solvent and the extracted solute. Distillation and solute precipitation are two promising options that can allow solvent to be recovered in a purity sufficient for reuse.
ADDED MATERIAL
Dr. J.B. Phillips can be reached at drjbond@usa.net.
REFERENCES
1. Allinger, N.L., M.P. Cava, D.C. DeJongh, C.R. Johnson, N.A. Lebel and C.L. Stevens. Organic Chemistry, 2nd Ed. (Worth; N.Y.: 1976).
2. Zubay, G. Biochemistry (Addison-Wesley; Reading, Mass.; 1983).
3. March, J. Advanced Organic Chemistry, 2nd Ed. (McGraw-Hill; N.Y.; 1977).
4. Burton, D.J. and K. Ravishankar. Treatment of Hazardous
Petrochemical and Petroleum Wastes (Noyes; Park Ridge, N.J.; 1989).
5. Treybal, R. E. Mass Transfer Operations, 3rd Ed. (McGraw-Hill; N.Y.; 1980).
6. EPA. 1992 Toxics Release Inventory (National Center for
Environmental Publications and Information; Cincinnati; 1994).
01Mar2001 INDIA: Role of biofertilizers in vegetable production.
PROGRESSIVE USE of biofertilizers offers the best alternative to intensive chemical fertilizers. Moreover, the biofertilizers are an economically viable.
Biofertilizers are living cells of different types of microorganisms (bacterial, algae, fungi), which have an ability to mobilise nutritionally important elements from non usable to usable form.
These microorganisms require organic matter for their growth and activity in soil and provide valuable nutrients to the plants in the soil. Biofertilizers are grouped broadly into three categories. Biological nitrogen fixers, phosphate solubilizers, mycorrahizae.
Biological nitrogen fixers
The process of biological nitrogen fixation is carried out by forming nodules on the roots of the plants. Rhizobium and Bradyrhizobiium form root nodules in leguminous plants like peas and beans, legumes are also known to leave behind some residual nitrogen in soil besides increasing the crop yield.
Similarly Azotobacter and Azospirillum play a key role in nitrogen nutrition of vegetables, cereals etc.
Phosphate solubilizers
When water soluable phosphate fertilizers are applied to soil, they are converted to unavailable forms due chemical fixation in soil. This problem is otherwise referred to as phosphorous fixation.
In such situations, a set of microorganisms viz. Bacillus megaerium Bacillus polymyxa, Pseudomonas striata, Aspergillus awamori, Pencillium can produce several organic acid (butyric acid, citric acid, fumaric acid etc.) and covnert unavailable phosphorus to available phosphorus which is called as phosphorus solubilization. Use of phosphorus solubilizers certainly enhances phosphorus availability and crop yield.
Mycorrhizae
Mycorrhizae denote symbiotic association between certain fungi and roots of plants. This is one of the recent biofertilizer which is known to help in uptake of several nutrients (P, Zn, Cu, Mn, Fe etc). It produces growth promoting substances, help in drought tolerance and impedes soil borne root pathogens.
Biofertilizers are applied to seed, seedling, seed material or soil. For seed treatment; 200g of biofertilizer is dissolved in 500 ml. of 10 per cent gur solution. Rub the mixture thoroughly on seeds and treated seeds are dried in shade for 30 minutes and then sown with in 24 hours.
For seedling treatments, 40 g of biofertilizer is dissolved in 15 litres of water and then root portion or seed material is dipped in the suspension for 10 minutes before planting.
For soil application, 800 g of biofertilizer is mixed with 10-20 kg of well powdered compost manure and then broadcast in an acre of crop.
R. K. Dhall
Department of Vegetable Crops
Punjab Agricultural University,
Ludhiana.
01Mar2001 INDIA: Protection of plant varieties.
The link between agriculture and the fulfilment of basic food needs should acquire primacy while introducing intellectual property rights on plant varieties. The most immediate consequence of the relevance of fundamental rights and basic needs is the need to circumscribe commercial activity so that it does not impact on food security at the individual level.
The present Bill does not consider the impact of the strengthening of patent rights on the realisation of fundamental rights such as the right to food and health, despite their close links.
This is the second part of a four part series on biodiversity, patents and plant variety bills that reflect India's obligations under the TRIPS and Biodiversity Convention.
THE PROTECTION of Plant Varieties and Farmers' Rights Bill constitutes the Government's response to its obligations under TRIPS concerning plant varieties. It is specifically required by a provision which forces all states to introduce intellectual property rights over plant varieties but allows them to choose the form of protection. The Bill was introduced in December 1999 and referred to a parliamentary committee which submitted its report in August last together with a substantially revised version of the Bill. This Bill should have been adopted by January 1, 2000 according to TRIPS deadlines and is to be considered in priority in the current session.
The Government has chosen not to impose patents over plant varieties but rather to devise its own system of intellectual property rights. Further, it was agreed that the UPOV Convention should not be ratified but that a law suited to the specific conditions of the country should rather be drafted. In its present form, the Bill focuses on the establishment of plant breeders' and farmers' rights. It is striking that the proposed regime for plant breeders' rights largely follows the model provided by the International Convention for the Protection of New Varieties of Plants (UPOV). It introduces rights which are meant to provide incentives for the development of the commercial seed industry. The criteria for registration are thus the same as those found in UPOV, namely novelty, distinctiveness, uniformity and stability. The Bill not only incorporates elements from the 1978 version of UPOV but also includes some from the much more stringent 1991 version, such as the possibility to register essentially derived varieties.
The second main aim of the Bill is to introduce farmers' rights. It is here that the Joint Committee has substantially changed the proposed law. Indeed, the first version only contained a short provision on farmers' rights which did not do justice to the complexity of the issue and was definitely not sufficient to justify the title of the Bill. After a series of hearings, the committee came to the conclusion that the Bill was unbalanced and decided to add a whole chapter on farmers' rights.
In the new version, the Bill seeks to put farmers' rights on a par with breeders' rights. It provides, for instance, that farmers can, like commercial breeders, apply to have a variety registered. Generally, the Bill envisions that farmers should be treated like commercial breeders and should receive the same kind of protection for the varieties they develop. The new provisions are significant in theory because they try to establish farmers' and breeders' rights as equal rights but they are unlikely to have a major impact in practice. This is due to the fact that the Bill accepts the registration criteria of the UPOV convention. These criteria have been developed exclusively with commercial breeders in mind and can generally not be applied for the registration of farmers' varieties since these are unlikely to fulfil all the conditions.
Benefit-sharing
In its 1999 version, the bill tried to compensate the lack of substantive farmers' rights with the introduction of two schemes for channelling to them some financial compensation. The idea behind `benefit-sharing' is that actors who have contributed to the development of a protected variety but cannot claim property rights are awarded monetary compensation instead.
The first scheme allows individuals or organisations to submit claims concerning the contribution they have made to the development of a protected variety. The final decision is taken by the authority established under the Act which determines the amount taking into account the importance of the contribution in the overall development of the variety and its commercial potential. The second benefit-sharing avenue allows an individual or organisation to file a claim on behalf of a village or local community. The claim relates to the contribution that the village or community has made to the evolution of a variety.Benefit-sharing in the plant variety Bill is problematic in several regards. First, it formalises the fact that some actors involved in plant variety management, such as farmers, cannot easily obtain property rights even though the possibility is now open to them in principle. Second, the Bill only conceives benefit-sharing as financial compensation even though other sharing schemes exist. Third, benefit-sharing focuses mainly on the genetic material that has been used in the development of a protected variety. Possible intellectual contributions to the development of a variety are not taken into account.
The Bill in context
It is important to keep in mind that the Bill has only been drafted in response to TRIPS obligations. It is therefore surprising to see that some of the core provisions of the Bill derive directly from an international treaty devised for countries with fundamentally different ground realities. Nothing in TRIPS forces states to adopt or even refer to UPOV.
After the revisions proposed by the committee, the Bill has acquired a much more balanced approach. However, the fact that the criteria for registration of plant varieties are those devised for commercial breeders may not allow farmers to benefit much from the provisions of the Bill. In its current form, it is clearly visible that the chapter on farmers' rights was added as an afterthought to a regime meant to benefit mostly commercial breeders. There is a need to recognise that the variety of actors engaged in agricultural management have rights to their resources or knowledge.
More fundamentally, the link between agriculture and the fulfilment of basic food needs should acquire primacy while introducing intellectual property rights on plant varieties. The most immediate consequence of the relevance of fundamental rights and basic needs is the need to circumscribe commercial activity so that it does not impact on food security at the individual level.
Patents Amendment Bill
The Patents Act of 1970 deals with patents in general and is not specifically related to biological resources. However, it addresses a number of issues that are of relevance in the present context. It rejects, for instance, the patentability of all methods of agriculture and is generally much more restrictive than similar laws in western countries. TRIPS now forces significant alterations to this Act. Thus, where only a product patent could be obtained for no more than seven years for food or medicine related inventions, TRIPS now requires the availability of product and process patents for 20 years.
The Patents (Second Amendment) Bill of 1999 generally seeks to modify the Act to allow compliance with TRIPS. There is not much scope to diverge from the rather precise TRIPS obligations if Parliament wants to avoid further confrontation with the World Trade Organisation (WTO). However, the exceptions contained in TRIPS have not necessarily been used to their full extent. Further, the present Bill does not consider at all the impact of the strengthening of patent rights on the realisation of fundamental rights such as the right to food and health, despite their close links.
With regard to environmental protection, the Bill includes some of the TRIPS exceptions related to environment and health. It also addresses the question of biopiracy by imposing the disclosure of the source and geographical origin of biological material used in a patented invention. Further, non-disclosure of the geographical origin or the anticipation of the invention in local or indigenous knowledge constitute grounds for opposing or revoking a patent.
Philippe Cullet
(The author is with the International Environmental Law Research Centre, Geneva. E-mail: pccullet@vsnl.net)
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