Daan Francois Toerien

Daan Francois Toerien
University of the Free State | ufs · Centre for Environmental Management

D.Sc. (Agric)

About

162
Publications
24,172
Reads
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1,846
Citations
Introduction
Presently exploring the interface between ecology and economic geography and how ecological approaches can contribute to a better understanding of enterprise dynamics in rural towns in South Africa and elsewhere. Prompted by Beinhocker's ideas about the similarities between biological life and business enterprises. Building upon my experiences in aquatic ecology and as an executive manager of scientific establishments and of businesses to explore this interface. It is a most stimulating field.
Additional affiliations
January 2009 - present
University of the Free State
Position
  • Research Associate
Description
  • Research on the interface between ecology and economic geography
October 1990 - March 1996
Council for Scientific and Industrial Research, South Africa
Position
  • Vice-President: Operations
Description
  • One of two Executive Vice-Presidents: Operations
October 1987 - September 1990
Council for Scientific and Industrial Research, South Africa
Position
  • Managing Director
Description
  • After restructuring of the CSIR appointed as Director of the Division of Water Technology
Education
February 1967 - September 1969
University of Pretoria
Field of study
  • Microbiology
February 1963 - October 1966
University of Pretoria
Field of study
  • Microbiology
February 1958 - November 1961
University of Pretoria
Field of study
  • Microbiology

Publications

Publications (162)
Article
Proportionality phenomena have earlier been observed in the enterprise structures of South African towns. A question remained whether small towns also exhibit such hidden order. Twelve towns of the Eastern Cape Karoo served as a case study to examine this. Towns' enterprises were identified, enumerated and classified into different business sectors...
Article
Full-text available
We investigated proportionalities in the enterprise structures of 125 South African towns through examining four hypotheses, (1) the magnitude of enterprise development in a town is a function of the population size of the town; (2) the size of an enterprise assemblage of a town is a function of the town's age; (3) there are statistically significa...
Technical Report
Full-text available
The importance of George as a national economic and development role-player in South Africa has been evident since the 1980s. Recognized as a secondary city, George had been variously identified as part of the development of a decentralization program, as a growth point, and as part of a strategy towards policy formulation for national urbanization...
Technical Report
Full-text available
In 2012/13 the Free State province of South Africa had 77 towns and villages apart from the city of Bloemfontein. There were 10567 formal enterprises in these towns (not including Bloemfontein). Their size distribution followed Zipf’s law. Two-thirds of FS towns have fewer than 130 enterprises, which in total amount to 2325 or 22% of all enterprise...
Article
Full-text available
Towards the end of the 20th century there were almost 500 small towns of fewer than 50 000 persons in South Africa, accommodating about one tenth of the country’s population. Little was known or said in national debates about the future of these places. A decade later this situation had changed and many studies have been or are being undertaken on...
Article
Full-text available
More than 3000 U.S. counties are used to examine a hypothesis that the enterprise dependency index (population numbers/enterprise numbers, EDI) can serve as a measure of community prosperity/poverty. The theoretical derivation of EDI is presented. Then, a slightly nonlinear relationship between the total and poor populations of the counties is reco...
Article
Four different South African groups are principally involved with research about entrepreneurship, namely groups focused on: (i) entrepreneurship, (ii) small towns, (iii) local economic development, and (iv) microeconomics of towns. There is limited cooperation between these groups, which if overcome could contribute to the reduction of community p...
Article
Full-text available
Exploring the interface between the manufacturing and tourism sectors in micropolitan statistical areas
Article
Full-text available
Micropolitan statistical areas (micropolitans) are important elements in understanding the small-town economic forces operating in the United States. This study focuses on the tourism enterprise dynamics of micropolitans. These dynamics are an oft-neglected element in tourism analyses and reports. Power law (log-log) regression analyses are central...
Chapter
Observations of the demographic-socioeconomic-entrepreneurial nexus of more than 3000 U.S. counties through eleven different lenses reveal an exceeding orderliness. Each lens consists of a set of ten power laws linking a specific property with ten other properties. In other words, 110 statistically significant power laws, some with super-linear, so...
Article
Full-text available
The importance of population-based scaling of the socioeconomic characteristics of cities has been regularly demonstrated over the past decade. Disproportionate population-based agglomeration of socioeconomic properties relative to one another are, therefore, common characteristics of cities. In other words, socioeconomic characteristic increase or...
Article
Full-text available
Debates about the value of pro-poor tourism indicated a need to revisit the links between the dynamics of tourism and hospitality enterprises and community poverty in rural South African towns. The numbers of tourism and hospitality enterprises in these towns are related to population numbers by a power law with a sub-linear exponent. The residents...
Chapter
Full-text available
Two decades of disappointing South African local economic development (LED) outcomes are possibly due to inattention to quantitative research of entrepreneurial dynamics. Brief reviews of the evolution of LED policies and practices and of quantitative entrepreneurial research are followed by a case study to reflect the value of such analyses. It re...
Chapter
Biosphere reserves face the challenge of sustainable development. They have to foster economic development that is ecologically and culturally sustainable. Paradoxically, the demographic-economic-entrepreneurial nexus of biosphere reserves has not been researched, an omission addressed here by studying the towns of the Gouritz Cluster Biosphere Res...
Article
Full-text available
Stagnant exports per capita and growing poverty in South Africa necessitated an examination of the links between the levels of productive knowledge (measured as enterprise richness), poverty (measured as Enterprise Dependency Indices) and entrepreneurial development (measured as the number of enterprises) in 188 South African towns. Two statistical...
Article
Full-text available
Statistically significant Pareto-like log-log rank-size distributions were recorded for population and enterprise agglomeration in the towns of three different regions of South Africa, and are indicative of skewed distributions of population and enterprise numbers in regional towns. There were no distinct differences between groups of towns of regi...
Article
Some small towns regress whilst others grow, i.e. a 'Small Town Paradox' (STP). Differential accumulation of productive knowledge could possibly be its cause. Suggestions that small towns in the Eastern Cape (EC) Karoo, South Africa survive only as a result of a state welfare system suggest that the STP does not occur in this semi-arid region. Prod...
Book
Full-text available
The potential economic and energy security opportunities of a medium to large shale gas resource could be substantial for South Africa; as are both the potential social and environmental risks associated with a domestic gas industry in the Central Karoo. The development of shale gas using vertical and horizontal drilling and hydraulic fracturing or...
Article
Full-text available
Enterprise richness (measured by the number of enterprise types) showed a statistically significant log-log relationship (or power law) with the total number of enterprises in (1) towns in different regions of South Africa and (2) towns in the same region but seven decades apart. Entrepreneurial space in towns develops or disappears in a regular wa...
Technical Report
Full-text available
This study has for the first time in South Africa provided a quantitative picture of enterprise development and dynamics in a biosphere, i.e. the Gouritz Cluster Biosphere Reserve (GCBR). The distribution of town populations, total enterprises, the enterprise numbers in many business sectors and the distribution of enterprise types follow power law...
Article
Full-text available
A strong underlying structure in the economic, demographic, and entrepreneurial domains of local authorities (municipalities) in the Free State, South Africa was detected through cluster and other analyses. The structure is indicative of a system in which economic value addition, population size, employment creation, and entrepreneurial domains are...
Article
Full-text available
330 ʼn Eeu van orde in sakeondernemings in dorpe van die Oos-Kaapse Karoo Daan Toerien D.F. Toerien, Navorsingsgenoot: Sentrum vir Omgewingsbestuur en Sentrum vir Ontwikkelingsteun, Universiteit van die Vrystaat Opsomming Vroeëre waarnemings van ʼn reglynige verband (direkte eweredigheid) tussen bevolkingsyfers en die getal sakeondernemings in Suid-A...
Article
Full-text available
We investigated proportionalities in the enterprise structures of 125 South African towns through examining four hypotheses, (1) the magnitude of enterprise development in a town is a function of the population size of the town; (2) the size of an enterprise assemblage of a town is a function of the town's age; (3) there are statistically significa...
Article
Full-text available
South Africa's imperatives for rural development and job creation raise the question whether water abundance in a region results in improved enterprise development in rural towns. The enterprise assemblages of 2 groups of towns, a river group from water-abundant areas and a Great Karoo group from the arid heartland of South Africa, were examined us...
Article
Full-text available
Two concepts, (1) companies are 'living' entities and (2) 'company ecology', stimulated our hypothesis that towns are 'enterprise ecosystems'. This hypothesis cannot be tested directly. However, if it is correct, application of clustering and ordination techniques used frequently in studies of natural ecosystems, should reveal clusters of towns tha...
Article
Full-text available
Two concepts, (1) companies are 'living' entities and (2) 'company ecology', stimulated our hypothesis that towns are 'enterprise ecosystems'. This hypothesis cannot be tested directly. However, if it is correct, application of clustering and ordination techniques used frequently in studies of natural ecosystems, should reveal clusters of towns tha...
Article
Integrated development planning (IDP) is a required process for local authorities in South Africa. It is, however, not required that historical analyses should form part of IDPs. This paper examines the consequences of this omission by comparing the historical development of the southwestern Cape, South Africa with the recent history and developmen...
Book
Full-text available
The planning of the economic future of local authorities, even of the country as a whole, rarely if ever addresses the role of technology in economic success or failure. I have come to the conclusion that we do so at our peril. The book, therefore, makes the case for the above conclusion and introduces new ways of thinking about the role of technol...
Article
It has been shown that attractive, viable and cost effective limestone stabilisation technologies exist for small and medium sized users. Use of correctly designed limestone contact systems eliminates most of the complications found in conventional stabilisation plants, and supervision and maintenance is minimal. Furthermore, a novel sidestream sta...
Article
Four small-scale sewage ponds were linked in series and fed settled sewage for 21 months. Inorganic nutrient (NH3-N) and (PO4-P) removal was primarily by biological uptake and export as algal material. NH3-N was reduced by 82% in the pond system, half of this removal according to chlorophyll α and total suspended solids data occurring in pond 1. Up...
Article
Eutrophication is a worldwide water pollution problem which results in the overabundant growth of algae and/or macrophytes (Wetzel, 1983). Control of the access of phosphates (P) to the aquatic environment is widely used as a eutrophication control strategy (e.g., Lee et al., 1978), thus requiring its removal from effluents by chemical and/or biolo...
Article
Four 10 m3 pilot scale, oxidation ponds linked in series were stocked with Clarias gariepinus (first three ponds) and on various occasions, combinations of Oreochromis mossambicus; Hypopthamichthys molitrix, Cyprinus carpio and Labeo umbratus were stocked in the fourth and last pond. During summer, O. mossambicus and C. carpio had average relative...
Article
Recirculation in a small scale waste stabilization pond system operated over a period of 12 months. Effluent from the third pond in a series of four ponds was added to the primary pond at a ratio of 1:1 (recirculated effluent:settled sewage effluent). Recirculation was stopped during winter for 35 days and during summer for 21 days to ascertain the...
Article
Heterotrophic bacterial activities in the soils from five habitats on sub-Antarctic Marion Island (46°54'S, 37°45'E) were estimated by a kinetic method for glucose mineralization and by a dehydrogenase assay. The dehydrogenase assay yielded more reproducible activity estimates than did the glucose mineralization method. However, the two methods res...
Article
The feasibility of using two fertilizers (urea plus superphosphate) in tap water as a medium for the mass culture of green algae (Scenedesmus and Ankistrodesmus) in outdoor plastic-enclosed minipond systems was investigated. Experiments in which the basic fertilizer-tap water medium was enriched with micro- and/or macronutrients revealed no nutrien...
Article
Full-text available
Anaerobic processes that can be used for the prevention of salination, eutrophication, and organic pollution of water, are reviewed in this paper. Sulfate which contributes to the salination of surface water, can be converted under anaerobic conditions to H//2S, from which sulfur can be recovered. The removal of phosphates and nitrates is essential...
Article
Full-text available
Sediment effects water quality in many ways. Visually, the most obvious effect is that of increasing turbidity. In the lower Vaal River this effect is being countered by the increasing salinity. A greater light penetration results in extensive blooms of rooted underwater macrophytes in sections of the lower Vaal River, but could also increase the l...
Article
A naturally developed Chlorella species was cultured on a fertilizer-tap water medium in outdoor plastic-enclosed units. Algal material, harvested from an actively growing culture, was analysed for crude protein, lipids, carbohydrates, ash and amino acid composition. The composition compared favourably with figures previously reported in the litera...
Article
Full-text available
Water word in die landbou vir besproeiing en as drinkwater vir mens en dier aangewend. Die besoedeling van water met soute, plantvoedingstowwe, organiese verbindings, patogene en parasiete, asook toksiese verbindings, verlaag die waarde van die water vir landboudoeleindes. Die sneile ontwikkeling van en die bevolkingstoename in Suid-Afrika sal wate...
Article
A pilot integrated aquaculture system for the treatment of effluent (COD = 3000–4000 mglitre−1) from a sorghum beer brewery was monitored for water quality and fish production over a period of 10 months. The system consisted of cultures of photosynthetic bacteria, algae (Closterium), fish (Oreochromis mossambicus) and macrophytes (Aponogeton distac...
Article
This communication presents the results of a laboratory study to evaluate the suitability of a fertilizer combination (industrial urea and superphosphate) in tap water as a medium for the mass culture of high quality algal material. the objectives were to investigate the chemical composition, solubility, and availability of the fertilizer nitrogen...
Article
A shallow turbid man-made impoundment was studied intensively for five years. The carbon (C) budget indicated a well balanced system, where phytoplankton productivity and respiratory losses accounted for the major inputs and outputs. The carbon content was dominated by dissolved organic carbon, followed by detritus > fish > phytoplankton > bacteria...
Article
The aqueous effluent generated by the Fischer--Tropsch process, containing a total of 13 g/L C(2)-C(5) monocarboxylic acids, was investigated as a potential substrate for the production of single-cell protein (SCP). A bacterial isolate, Acinetobacter calcoaceticus, could utilize all the acids in the effluent simultaneously in chemostat cultures, an...
Article
The heterotrophic activities of suspended microbes (bacterioplankton), of ‘aufwuchs’ (epiphytic microbes), of microbes in the surface of sludge (solids settled out of the waste-water) and sediment (soil) layers and of microbes at the air-water interface of a macrophyte bed receiving piggery effluent, were compared. Comparisons were based on 14C-glu...
Article
A cattle feedlot waste system consisting of a high-rate algal pond and a fish pond was regularly sampled for bacteriological analyses. High numbers of aerobic and anaerobic bacteria and potential pathogens (e.g. Salmonela spp.) were present in the waste water. The waste treatment system reduced all bacterial groups by more than 99·6%. The skin, gil...
Article
One hundred bacterial isolates from cattle feedlot effluents were isolated on MacConkey Agar and phenotypically characterized (with the API 20E microtube system). Identities were assigned according to a Profile Index or following numerical classification. Escherichia coli (24), Citrobacter freundii (14), Enterobacter spp. (7), Salmonella spp. (3) a...
Article
Qualitative and quantitative laboratory investigations of bacterial-algal interrelationships were carried out using Gram-negative rod-shaped bacteria and an alga (Scenedesmus quadricauda) isolated a pond system treating cattle feedlot effluent. The results suggested that most bacterial groups, including Flavobacterium, Citrobacter, Salmonella, Aero...
Article
The effect of the growth rate on the macromolecular cell composition of the bacterium Acinetobacter calcoaceticus was investigated in carbon-limited chemostat culture. Only a minor change in the DNA and protein content was observed. Because of the improved cell yield at the higher growth rates due to the maintenance energy requirement of the cells,...
Article
The oxygen dynamics and heterotrophic activities of a waste treatment system, consisting of a storage pond, a high rate algal pond (HRAP) and a fish pond, which handles the effluent from a cattle feedlot are presented. Long-term and short-term observations suggest that BOD loading rates of 9·5 to 35 gm−2 day−1 can be used in the HRAP, depending on...
Article
Growth models have been developed using data from recent greenhouse studies on the effects of nitrogen, phosphorus and temperature on growth rates of Salvinia molesta Mitchell. Linear transformations were used for estimating Michaelis-Menten kinetic constants and a significant fit of the data was obtained. This has been confirmed by a comparison wi...
Article
Full-text available
The V(max) and turnover rates (TR) of [U-C]glucose uptake and mineralization of Lake Kinneret (Israel) sediment are temperature dependent. The following activation energies were determined: glucose uptake, approximately 15,000 cal (62,760 J); TR of glucose uptake, approximately 10,000 cal (41,840 J); glucose mineralization, 7,500 to 15,000 cal (31,...
Article
The temperature-growth rate responses of bacterial isolates from Wuras Darn, a silt-laden, highly turbid impoundment were described well by Arrhenius equations. Activation energies varied from 10, 15 to 29, 59 kcal moles, indicating a varied response to temperature changes. Since Q10 (15 to 25°C) values of more than 3, 0 were generally encountered,...
Article
The API 20E system was applied and evaluated for the identification of 60 bacterial contaminants, isolated from South African lager beer breweries and tentatively identified as Enterobacteriaceae. The results were compared with the groupings obtained by polyacrylamide gel electrophoresis of soluble proteins and by gas chromatography of volatile met...
Article
The growth parameters of Acinetobacter calcoaceticus, relevant to its mass cultivation on acetate and ethanol, were determined in batch and continuous culture experiments. Acetic acid exhibited a more powerful inhibitory effect on the growth rate than ethanol. In batch culture, the acetate component of an acetate-ethanol substrate pair was preferen...
Article
Phenotypic properties, metabolic end products and gel electrophoretic protein patterns of indole‐negative and indole‐positive Klebsiella pneumoniae strains isolated from beer breweries are reported. Results obtained clearly indicate that the indole positive K. pneumoniae strains represent a distinct group of klebsielleae and that they should be pla...