Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Integrated treatment of tapioca processing industrial wastewater based on environmental bio-technology
    Huynh Ngoc Phuong Mai, - \ 2006
    Wageningen University. Promotor(en): Gatze Lettinga, co-promotor(en): N.T. Viet. - [S.l. ] : S.n. - ISBN 9789085044413 - 180
    afvalwaterbehandeling - tapioca - voedselverwerking - anaërobe behandeling - rioolslib - vietnam - fabrieksafvalwater - waste water treatment - tapioca - food processing - anaerobic treatment - sewage sludge - vietnam - factory effluents
    Tapioca processing wastewater containing high COD (9,630-13,760 mg/L), BOD (7,280-11,510 mg/L), SS (450-1,850 mg/L), total nitrogen (291-355 mg/L) total phosphorus (39-73 mg/L) and low pH (3.4-4.6) are one of the major causes of severe pollution to receiving source in South Vietnam. Based on the characteristics of tapioca processing wastewater, biological treatment processes are selected for study. In which the UAF, UASB, aeration tank and pond system are in series. For this treatment technology, the UAF reactor is used as pre-treatment for reducing of SS. The SS removal efficiencies ranged from 67-82%, equivalent to influent SS decreased from 450-1,850 mg/L to 148-290 mg/L. The core of treatment system is the UASB-reactor, which is responsible for the removal of organic matter. The OLR of UASB-reactor can achievedto 42 kgCOD/m 3 .d with HRT8.3-8.4 hours. The influent COD decreased from 10,498-14,330 mg/L to 1,082-2,178 mg/L, equivalent with treatment efficiencies ranged from 82.5-90.7%. The aeration tank and pond system are used as post-treatment. They take responsibility for the remainder of organic matter, nitrogen and phosphorus removal. With the HRT around 6-8 hours for aeration tank and 6-7 days for pond system, the effluent COD, total nitrogen and total phosphorus ranged from 78-94 mg/L, 4.5-5.7 mg/L, 7.3-7.9 mg/L, respectively. In the UASB-reactor, the granular sludge was observed after 20 days of operating at OLRof 6 kgCOD/m 3 .d. The study also showed that nutrients and trace elements are necessary for tapioca wastewater treatment using UASB-reactor, but only for start-up period, when OLR lowerthan 20 kgCOD/m 3 .d. The UASB-reactor was able to stand a shock load as the COD concentration three times higher than normal, in 24 hrs stretches, without any damage and the completed recovery took 2-3 days.The investigateon cyanide toxicity showed that cyanide exerts a distinct toxicity, in particular on the hydrolysis process of tapioca starch particles. Hence, hydrolysis of these particles was completed within 2 days in the control experiment (using 2g starch particles and 2 gVSS/L in the experiment conducted at 30 o C), while at a high cyanide concentration of 120 mgCN - /L it took up to 6 days. But compared to the hydrolysis process, the acidification process is much less affected by cyanide; acidification always proceeded immediately after hydrolysis of the starch particles. The experiments of reduction the cyanide toxicity showed that sulphide ions do not reduce the toxicity of cyanide through the formation of thiocyanate, but instead reinforce the toxicity of cyanide. And the addition of Fe 2+ significantly reduces the toxicity of cyanide on the hydrolysis and methanogenesis through the formation of the ferro-cyanide complex, but it does not stimulate the degradation of cyanide.The conclusions of the research showed that the solution comprising the implementation of the AnWT-technology combined with aerobic post-treatment, clearly demonstrates the big benefit of the energy cost savings and resource conservation together with its feasibility to meet really extremely severe discharge standards. It also shows how strong returns can be generated for investors using CDM. The estimate shows that the required treatment system with a capacity of 2,000 m 3 /d will produce 4,200 - 6,200 m 3 biogas per day (>60 % methane gas), which is equivalent to 2,600 - 3,800 liters of FO per day. And energy cost savings to the plant are estimated at 850 - 1,260 US$ per day.
    Analysing and governing environmental flows: the case of Tra Co tapioca village, Vietnam
    Mol, A.P.J. ; Tran Thi My Dieu, - \ 2006
    NJAS Wageningen Journal of Life Sciences 53 (2006)3-4. - ISSN 1573-5214 - p. 301 - 317.
    landbouwindustrie - duurzaamheid (sustainability) - milieueffect - tapioca - cassave - technologie - gesloten systemen - vietnam - agribusiness - sustainability - environmental impact - tapioca - cassava - technology - closed systems - vietnam
    Environmental flows are of crucial importance for questions of sustainability. But analysing only the material side of environmental flows brings us half way understanding questions of sustainability. This article reports on the development of a more integrative approach in studying environmental impacts of agro-industrial systems in Asia, taking tapioca (cassava starch) processing in Vietnam as an example. The analysis of material flows and technological options to close material cycles is combined with an actor-network analysis from three angles: a policy, an economic and a social perspective, respectively. The paper finally assesses the additional value of the developed methodology and points out ways for further investigation and development of a more integrative approach to industrial transformations
    Greening Food Processing Industry in Vietnam: Putting Industrial Ecology to Work
    Tran Thi My Dieu, - \ 2003
    Wageningen University. Promotor(en): Arthur Mol; Wim Rulkens. - [S.l.] : S.n. - ISBN 9789058088253 - 290
    industrieel afval - chemische ecologie - voedselindustrie - verontreinigingsbeheersing - ecosystemen - tapioca - suikerindustrie - zoetwarenindustrie - cacao- en chocolade-industrie - zuivelindustrie - vietnam - industrial wastes - chemical ecology - food industry - pollution control - ecosystems - tapioca - sugar industry - confectionery industry - cocoa industry - dairy industry - vietnam

    The significant contribution to Vietnam's gross domestic product over the years give evidence of the important role of food processing industry in the economic and industrial development of the country. This is even more relevant from now onwards, as it is Vietnam's development strategy to become one of the top agricultural countries in the world by the year 2010. However, it is not difficult to recognize that the rapid growth of food processing industry in Vietnam goes together with environmental deterioration and puts stress on natural resources. So far, most efforts in environmental management of (food processing) industry in Vietnam have mainly been focussing on dealing with wastes and emissions after they have been generated. While to some extent, this end-of-pipe approach helps to reduce or eliminate adverse environmental impacts from the generated wastes and emissions, in most cases, the isolated implementation of this approach shows several disadvantages, shortcomings and inefficiencies. Thus, it should not surprise us that environmental quality in Vietnam is still poor, although the end-of-pipe approach has been implemented from the early 1990s onwards.

    In order to reduce present and future threats to human health and the environment, industrialized countries have developed and introduced alternative approaches, which can overcome some of the weaknesses of end-of-pipe treatment solutions and are more (economic and environmentally) effective and efficient in reducing the generation of wastes. From existing literature and the experiences of industrialized countries we can clearly envision various advantages of environmental protection strategies that are based on cleaner production, waste exchange (offsite reuse and recycling) or industrial ecology approach instead of end-of-pipe treatment solely. Certainly, each of these approaches can only be applied successfully in some circumstances and is limited in others. Therefore the combination and integration of some or all these approaches is often seen as the best or only strategy to overcome the continuing environmental deterioration. This potential is investigated in this study. The core objective of this research is to analyze and assess the possibilities and the potency for greening food processing industries in Vietnam, based on the combination and integration of existing pollution treatment and prevention approaches. More specifically, this study seeks to fulfil the questions on: how to apply and adapt the existing experiences of industrial ecosystem from highly industrialized Western countries to develop an (agro)-food processing industrial ecosystem with the existing institutions, technological and socio-economic conditions of Vietnam? Whether it is possible to apply these ideas for large stand-alone firms as well as small (household) and medium sized (agro)- food processing companies? What would be core features of a zero waste industrial ecosystem model of food processing industry in Vietnam? Which actors, institutions and relations are crucial or potentially crucial to introduce the proposed model in practice?

    Dealing with these questions, a methodology to analyze and design pollution prevention models for (agro-food processing) industries, integrating the physical-technological and socio-institutional models is developed. Using various theoretical ideas of cleaner production/waste minimization, waste exchange and industrial ecology, a methodology towards physical-technological models of a zero waste industrial ecosystem is established having four basic steps. The methodology starts with analyzing the material and energy flows that run through the industrial systems and partly end up in wastes, followed by analyzing various possibilities to prevent the generation of wastes in the second step. The third step concentrates on identifying, analyzing and designing potential offsite recovery and reuse options. The last step entails the identification of remaining wastes that need to be treated properly before discharging into the environment. Together, these four steps form a systematic methodology that leads us towards (close to) a physical-technological model for a zero waste industrial ecosystems. In addition, taking into account complex political, economic and social relations between the industrial system and actors outside, the triad-network model developed by Mol (1995) is applied to complement the physical-technological model with an actor and institutional analysis. The roles of actors and the interrelations between them and industrial systems are investigated in three networks: economic, policy and societal network.

    The applicability of the developed methodology is assessed by applying it on different cases of the Vietnamese food industrial sector. Three case studies (at tapioca producing households in Tra Co Village, a large-scale tapioca processing plant of Tan Chau-Singapore Company, and food processing companies in Bien Hoa 1 IZ) represent differences between: (1) small/household-scale enterprises and large-scale companies; (2) one enterprise and a group of enterprises; (3) a group of enterprises from one industrial sector and a group of enterprises from different industrial sectors (but still within the broad category of agro-food industries); (4) enterprises located within and outside industrial zones, as industrial zones have specific advantages in industrial ecology design.

    In general, these case studies illustrate that excessive generation of non-products (including reusable/valuable materials, wastes and air pollutant emission) arises due to: inefficient technology, inadequate processing, inadequate onsite and offsite reuse and recycling, cheap natural resources, financial limitations, no strict enforcement and lack of incentives on pollution prevention.

    Experiences from the three case studies have made clear that failures in current environmental management due to improper performance of the existing actors and institutions can be indicated in the following five points. First, state environmental management authorities, especially provincial DOSTEs, face difficulties of high workload, lack of expertise, and scare resources for monitoring and enforcement. Second, specific regulations and incentives for producers to make their production processes more ecologically sound and to reuse and recycle wastes are completely lacking at the moment. Third, influences from economic agencies do not seem to encourage producers to improve their production efficiencies and environmental performances. Fourth, there is hardly any enduring relation between research institutes and the producers in neither production nor environmental protection. Finally, civil society is not actively involved in environmental issues.

    Seeking possibilities to overcome the causes of excessive generation of non-products, these case studies have revealed that cleaner production, waste exchanges and ideas of industrial ecology are valuable in greening food processing industry, though the feasible technical options and organizational schemes are different in the different cases. The diversity of industrial system situations in Vietnam in terms of scale, size, industrial sector and location causes a number of dissimilarities in the proposed options and implementations to approach a zero waste (food processing) industrial ecosystems. Therefore, this study concludes that any general or national approach to green food processing industry is doomed to fail in practice if in its operationalization these differences are not taken into account. Though several constraints (in terms of technical dimensions, environmental policy, economic aspects and public participation) hampering the implementation of the proposed physical technological models of zero waste industrial ecosystems were found from the case studies, there also appear several opportunities to overcome these constraints.

    The possibilities and approaches for greening food processing industry in Vietnam learned by experiences from these case studies can be generalized in a physical-technological model, in which (food processing) industry and agriculture cooperate. This model consists of food processing enterprises and all or some of the following components: other enterprises, which use products from food processing enterprises as raw materials, livestock feed production enterprise, fish culture households, livestock breeding households, composting plant, biogas production plant, agricultural fields and wastewater treatment plant. Though operationalization of this physical-technological model will vary due to the diversity of (food processing) industrial systems, this generalized model is the foundation for governmental authorities, planers, policy makers and environmentalists in reforming existing industrial systems and establishing new industrial systems as well.

    Though several similarities and dissimilarities arose from the three case studies, it is possible to draw two general conclusions on the proposed methodology. First, the methodology to design a physical-technological model of a zero waste industrial ecosystem following four basic steps proved feasible to apply to any industrial system. Second, the case studies show that without an analysis of actor and institutions, any physical-technological model remains a theoretical possibility at best. An analysis of actors and institutions following a triad-network model proved useful in all studied industrial systems.

    At last, this study specifies five crucial points, which reflect the very Western ideas of Industrial Ecology Concept when applied in Vietnam. First, the industrial ecology concept has been applied especially in Europe and USA market economics with advanced technological systems, while Vietnam is a less technological development country. Therefore, with the same kind of industrial sector, the application of industrial ecology in Vietnam will differ from European and American ones. Second, in Vietnam, the organizational and institutional structures around industry and industrial systems are in general simpler than what we see in Western countries. This means that an operationalisation of industrial ecology can rely less on all kinds of advanced organizational models. Third, a number of socio-institutional conditions that are crucial for advancing and implementing industrial ecology models in practice as present in advanced industrialized societies are absent or less developed in Vietnam. Thus, developing feasible options that have a high chance to be implemented and succeed in Vietnam will be different from those developed in advanced industrialized countries. Fourth, Vietnam still has a large number of reuse and recycling practices that are not so much motivated by environmental considerations but rather by economic ones. With further development of the economy in Vietnam, these existing recycling and reuse practice might come under pressures and need to be 'protected': that is an active industrial ecology policy needs to be developed to continue these practices. Finally, the large agricultural sector together with the large proportion of the land used for agricultural production opens favorable conditions for agro-industrial ecology models and practices in Vietnam.

    Fabricage van tapioca - zetmeel
    Anonymous, - \ 1976
    Wageningen : Pudoc (Literatuurlijst / Centrum voor landbouwpublikaties en landbouwdocumentatie no. 3966)
    bibliografieën - cassave - manihot esculenta - tapioca - bibliographies - cassava - manihot esculenta - tapioca
    Cassava
    Anonymous, - \ 1976
    Wageningen : Centrum voor Landbouwpublikaties en Landbouwdocumentatie (Literatuurlijst / Centrum voor landbouwpublikaties en landbouwdocumentatie no. 3981)
    bibliografieën - cassave - manihot esculenta - tapioca - bibliographies - cassava - manihot esculenta - tapioca
    Tapioca
    Anonymous, - \ 1967
    Wageningen : [s.n.] (Litearatuurlijst. Centrum voor landbouwpublikaties en landbouwdocumentatie no. 2815)
    bibliografieën - cassave - manihot esculenta - tapioca - bibliographies - cassava - manihot esculenta - tapioca
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