Using chemical process simulation to design industrial ecosystems

Chemical process simulation (CPS) software has been widely used by chemical (process) engineers to design, test, optimise, and integrate process plants. It is expected that industrial ecologists to bring these same problem-solving benefits to the design and operation of industrial ecosystems can use CPS. This paper provides industrial ecology researchers and practitioners with an introduction to CPS and an overview of chemical engineering design principles. The paper highlights recent research showing that CPS can be used to model industrial ecosystems, and discusses the benefits of using CPS to address some of the technical challenges facing companies participating in an industrial ecosystem. CPS can be used to (i) quantitatively evaluate and compare the potential environmental and financial benefits of material and energy linkages; (ii) solve general design, retrofit, or operational problems; (iii) help to identify complex and often counter-intuitive solutions; and (iv) evaluate what-if scenarios. CPS should be a useful addition to the industrial ecology toolbox.     

Detection of fetal HLA-DQα sequences in maternal blood: A gender-independent technique of fetal cell identification

The objective of this study was to detect fetal HLA-DQα gene sequences in maternal blood. HLA-DQα genotypes of 70 pregnant women and their partners were determined for type A1. We specifically sought couples where the father, but not the mother, had genotype A1. In 12 women, maternal blood samples were flow-sorted. Candidate fetal cells were isolated and amplified by using PCR primers specific for a paternal HLA-DQα A1 allele. Fetal HLA-DQα A1 genotype was predicted from sorted cells; amniocytes or cheek swabs were used for confirmation. Six of twelve sorted samples had amplification products indicating the presence of the HLA-DQα A1 allele; 6/12 did not. Prediction of the fetal genotype was 100 per cent correct, as determined by subsequent amplification of amniocytes or cheek swabs. We conclude that paternally inherited uniquely fetal HLA-DQα gene sequences can be identified in maternal blood. This system permits the identification of fetal cells independent of fetal gender, and has the potential for non-invasive prenatal diagnosis of paternally inherited conditions.     

The Ethical Contract as a Tool in Organic Animal Husbandry

This article explores what an ethicfor organic animal husbandry might look like,departing from the assumption that organicfarming is substantially based in ecocentricethics. We argue that farm animals arenecessary functional partners in sustainableagroecosystems. This opens up additional waysto argue for their moral standing. We suggestan ethical contract to be used as acomplementary to the ecocentric framework. Weexpound the content of the contract and end bysuggesting how to apply this contract inpractice. The contract enjoins us to share thewealth created in the agroecosystem (by ourjoint contributions) by enjoining us to carefor the welfare and needs of the individualanimal, and to protect them from exploitation(just as human co-workers should not beexploited). The contract makes promoting goodanimal welfare a necessary condition forbenefiting farm animals. Animals for their partare guaranteed coverage under the contract solong as they continue to contribute to thesystem with products and services.     

The first commercial supercritical water oxidation sludge processing plant

Final disposal of sludge continues to be one of the more pressing problems for the wastewater treatment industry. Present regulations for municipal sludge have favored beneficial use, primarily in land application. However, several agencies and entities have warned of potential health risks associated with these methods. Hydrothermal oxidation provides an alternative method that addresses the health concerns associated with sludge disposal by completely converting all organic matter in the sludge to carbon dioxide, water, and other innocuous materials. A hydrothermal oxidation system using HydroProcessing, L.L.C.'s HydroSolids process has been installed at Harlingen, Texas to process up to 9.8 dry tons per day of sludge. Based on a literature review, this system is the largest hydrothermal oxidation system in the world, and the only one built specifically to process a sludge. Start up of Unit 1 of two units of the HTO system began in April 2001. Early results have indicated COD conversion rates in excess of 99.9%. Harlingen Waterworks System estimates that the HydroSolids system will cost less than other alternatives such as autothermal thermophilic aerobic digestion and more traditional forms of digestion that still require dewatering and final disposal. The Waterworks intends to generate income from the sale of energy in the form of hot water and the use of carbon dioxide from the HydroSolids process for neutralization of high pH industrial effluent. The Waterworks also expects to generate income from the treatment of septage and grease trap wastes.     

Synthesis of zinc-carboxylate metal-organic frameworks for the removal of emerging drug contaminant (amodiaquine) from aqueous solution

We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2(fum)2(bpy)] and [Zn4 O(bdc)3](fum = fumaric acid; bpy =4,4-bipyridine; bdc = benzene-1,4-dicarboxylate) metal–organic frameworks(MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared(FT-IR) spectroscopy, and powder X-ray diffraction(PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R~2 values of 0.973 and0.993 obtained for [Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62 mg/g on the[Zn_2(fum)_2(bpy)] and [Zn_4 O(bdc)_3] MOFs respectively, and were obtained at p H of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.     

Colonial breeding and nest defence in Montagu's harrier (Circus pygargus)

We assessed whether colonial breeding allows individuals to decrease their investment in predator defence, by presenting decoys of owls, foxes and crows to Montagu's harrier, Circus pygargus. Decoy detection increased with colony size, as did the number of individuals mobbing the decoy. The number of mobbers was greater for predators potentially risky for the adults (owl or fox) than for non-dangerous predators (crow). Recruits (breeding neighbours, fledglings and non-breeders) were present a lower percentage of the time, and attacked and alarm called less frequently than tested individuals. Nevertheless, the overall attack rate on the predator increased with the number of mobbers. When the size of the mobbing group increased, individuals were more likely to attack predators that represented a risk for adults, but did so less intensively and with a lower frequency of close dives. Thus, coloniality decreased the individual costs of defence in terms of risk taken, whilst enhancing defence efficacy. Birds alarm called more intensively when presented with dangerous predators than with the crow. The number of recruits significantly increased with increasing alarm rate of the tested individuals, even when taking colony size into account. Furthermore, the alarm rate of the tested birds also had a significant effect on the proportion of recruits that engaged in attacks against dangerous predators but not against the crow. The higher recruitment and attack rates for dangerous predators were thus apparently modulated through alarm calling. We discuss whether tested birds may manipulate recruits' behaviour to lessen their own risk.     

Degradation of Starch–Calcium Carbonate Disposable Packaging in a Solid Waste Composting Facility

The compostability of starch–CaCO₃ disposable packaging was examined in a source-separated municipal solid waste (MSW) composting facility located in East Hampton, NY. Source-separated MSW:starch–CaCO₃ container mixtures of 0 (control), 5, and 20% (by volume) were prepared as feedstock for composting. Compost samples were collected weekly or biweekly during the composting process and examined for fragments of the starch–CaCO₃ containers. Changes in compost quality due to the presence of starch–CaCO₃ containers were assessed by measuring the nutrient and metal content of the three resultant MSW:starch–CaCO₃ composts. Finally, plant growth studies were conducted to examine the composts for possible plant growth inhibition due to the deterioration of the starch–CaCO₃ containers. Results showed that portions of the starch–CaCO₃ containers were not identified in any of the 5 and 20% sieved and characterized compost fractions > 1.3 cm following 1–3 weeks of composting. Mechanical agitation of the waste along with optimum composting conditions were sufficient to initiate the rapid degradation of the starch–CaCO₃ composites. Degradation of starch–CaCO₃ containers did not affect compost nutrient and trace element content. Grass biomass measurements were performed once weekly over 28 days for grass grown in control (0%), 5%, and 20% starch–CaCO₃-containing compost:soil mixtures. Significant differences in grass biomass for these compost:soil mixtures were measured only for the 0 and 20% starch–CaCO₃-containing compost:soil mixtures at 28 days (9.07 vs 11.05 g, respectively; P = 0.046).     

Behaviour of Dioxins,Furans and Metals Associated with Stabilized Msw Combustor Ash in Sea Water

This report presents the results of a research programme designed to examine the engineering and environmental acceptability of stabilizing municipal solid waste (MSW) combustor ash for artificial reef construction. Municipal solid waste combustor ash was combined with Portland cement to form solid blocks using conventional construction block making technology. the resultant stabilized combustor ash (SCA) blocks were used to construct an artificial habitat in Conscience Bay, Long Island Sound, New York and compared to identical concrete blocks, fabricated using natural aggregates. Over a 4.5 year period divers periodically returned to the site to monitor the interaction of SCA blocks with the marine environment and compare the performance of these blocks with the concrete control blocks. Results show that the SCA blocks retain their strength after prolonged sea water exposure. Contaminants of environmental concern, including metals, dioxins and furans, were retained within the cementitious matrix of the SCA blocks after prolonged sea water submersion. in addition, organisms growing on the surfaces of the SCA blocks did not accumulate contaminants from the blocks.     

Nutrient transfer in a marine mutualism: patterns of ammonia excretion by anemonefish and uptake by giant sea anemones

Many symbioses involve multiple partners in complex, multi-level associations, yet little is known concerning patterns of nutrient transfer in multi-level marine mutualisms. We used the anemonefish symbiosis as a model system to create a balance sheet for nitrogen production and transfer within a three-way symbiotic system. We quantified diel patterns in excretion of ammonia by anemonefish and subsequent absorption by host sea anemones and zooxanthellae under laboratory conditions. Rates of ammonia excretion by the anemonefish Amphiprion bicinctus varied from a high of 1.84 μmole g⁻¹ h⁻¹ at 2 h after feeding, to a basal rate of 0.50 μmole g⁻¹ h⁻¹ at 24–36 h since the last meal. Conversely, host sea anemones Entacmaea quadricolor absorbed ammonia at a rate of 0.10 μmole g⁻¹ h⁻¹ during the daytime in ammonia-enriched seawater, but during the night reduced their absorption rate to near zero, indicating that ammonia uptake was driven by zooxanthella photosynthesis. When incubated together, net ammonia excretion was virturally zero, indicating that host anemones absorbed most of the ammonia produced by resident fish. Adult anemonefish weighed about 11 g under laboratory conditions, but on the coral reef may reach up to 64 g, resulting in a maximal potential ammonia load of >200 μmole h⁻¹ produced by two adult fish during daylight hours. In contrast, host sea anemones weighed about 47 g in the laboratory, but under field conditions, large individuals may reach 680 g, so their maximal ammonia clearance rates may reach about 70 μmole h⁻¹ during the daytime. As such, the ammonia load produced by adult anemonefish far exceeds the clearance rate of host anemones and zooxanthellae. Ammonia transfer likely occurs mainly during the daytime, when anemonefish consume zooplankton and excrete rapidly, and in turn the zooxanthellae are photosynthetically active and drive rapid ammonia uptake. We conclude that zooplanktivorous fishes that form mutualisms with coral reef cnidarians may serve as an important link between open water and benthic ecosystems, through the transfer of large quantities of nutrients to zooxanthellate hosts, thus enhancing coral reef productivity.