Modelling solute transport in structured soils: performance evaluation of the ADR and TRM models

The movement of chemicals through the soil to the groundwater or discharged to surface waters represents a degradation of these resources. In many cases, serious human and stock health implications are associated with this form of pollution. The chemicals of interest include nutrients, pesticides, salts, and industrial wastes. Recent studies have shown that current models and methods do not adequately describe the leaching of nutrients through soil, often underestimating the risk of groundwater contamination by surface-applied chemicals and overestimating the concentration of resident solutes. This inaccuracy results primarily from ignoring soil structure and nonequilibrium between soil constituents, water, and solutes. A multiple sample percolation system (MSPS), consisting of 25 individual collection wells, was constructed to study the effects of localized soil heterogeneities on the transport of nutrients (NO−3, Cl−, PO3−4) in the vadose zone of an agricultural soil predominantly dominated by clay. Very significant variations in drainage patterns across a small spatial scale were observed (one-way ANOVA, p < 0.001 indicating considerable heterogeneity in water flow patterns and nutrient leaching. Using data collected from the multiple sample percolation experiments, this paper compares the performance of two mathematical models for predicting solute transport, the advective-dispersion model with a reaction term (ADR), and a two-region preferential flow model (TRM) suitable for modelling nonequilibrium transport. These results have implications for modelling solute transport and predicting nutrient loading on a larger scale.

Anaerobic treatment of juice and fruit-processing effluents

Effluents from the juice and fruit processing industries have high organic matter content. Discharge of these effluents without appropriate treatment would therefore have a negative impact on the environment. High organic contents and low contamination levels make such effluents suitable for biological treatment, especially anaerobic digestion. In the latter process, significant amounts of digester gas can be produced, turning a waste stream into a source of renewable energy that can be used for electricity and heat production, leading to financial benefits.This paper investigates the feasibility of anaerobic digestion and the gas generation potential of five different effluents from the carrot-juice, orange-juice and sultana processing industries. Benefits are assessed in terms of digester gas production and organic matter reduction. The results show that the specific gas production ranges between 665 and 860 m3 per tonne of effluent treated (as organic dry matter). Furthermore, nearly 100% of the organic matter is converted into gas in the case of the carrot- and orange-juice processing residues, while a 84.5% reduction of the organic matter was found to be achievable in the case of the sultana wastes. While these results are promising, further testing will be required to validate them in a larger scale.

A framework for material management in the building demolition industry

Conventional mechanical building demolition produces numerous solid wastes, most of which are sent to landfill directly and severely degrade the living environment. Just-in-time building demolition has been developed recently with a management strategy to facilitate waste reuse. Procurement management plays a significant role in just-in-time building demolition. In particular, the demolition tendering selection needs to consider contractors' environmental performance in addition to project costs. Moreover, the flow of building materials in a demolition project may be regarded as a supply chain involving the building owner, demolition contractor and material demanders. This paper develops a framework for salvaged materials management in the emerging demolition industry. The research is to promote the recycling and reuse of building demolition materials in order to achieve better environmental and financial performance for building demolition projects.

The environment always matters

Superficially, the high human populations of prosperous, well-fed city-states such as Singapore and Hong Kong might appear to support the view that high concentrations of human dynamism and enterprise can alone transcend environmental constraints. Indeed, extrapolations from such densely populated regions to the whole world form the historical basis for the most optimistic estimates of how many people the Earth might support. In fact, these affluent, densely populated regions require goods and services that are produced by areas far larger than the residential area of the state. For the foreseeable future, the whole world cannot live as densely and as well as Singapore. For example, some of the fish eaten in Hong Kong is captured in Pacific Island fisheries. Beef from the Northern Territory is exported to Japan. More generally, the supply of environmentally dependent goods - including sinks for wastes - is always limited, as are inputs such as fertile soil, clean fresh water and a benign climate.

'Green' treatment of acid mine drainage - a step towards sustainability

Sustainability is becoming increasingly important in the mining and mineral processing industries and must incorporate the associated waste products. Acid mine drainage (AMD) is one such by-product and is one of the most serious environmental problems facing the minerals industry today. The oxidation of sulphidic mine wastes often continues for a substantial period of time after mine closure, resulting in difficult and costly remediation and rehabilitation works. Mining companies are often reluctant to spend increasing amounts of money on waste treatment when the mine life is limited or even finished. Hence a simple, low maintenance and low-cost method of treating AMD is required. Whilst this paper does not address the issue of AMD, it does propose methods for removal of individual species from AMD with potential benefits, including raising AMD pH.

A novel concept of using biosolids as a biological adsorbent, or ‘biosorbent’, of metals from AMD is being investigated at a laboratory/pilot scale level. Biosolids are a by-product resulting from the biological treatment of wastewater, and have been previously shown to adsorb metals from aqueous solutions. This could lead to an environmentally sustainable or ‘green’ method for treating both AMD discharges and disposing/reusing the biosolids.

The result of a laboratory-scale study of the biosorption of Zn(II) is presented in this paper. Physical parameters including reaction kinetics, mixing speed and solution pH were investigated. Solution pH also rose an average of 2 pH units over the 24 hour equilibrium time – a valuable side effect when treating acid mine drainage. The outcome of the study highlights the usefulness of biosolids as a biosorbent for the removal/recovery of metal ions from acid mine drainage. A simple, low-cost treatment technology requiring low maintenance would be beneficial to the mining industry to address some issues relating to AMD and would help integrate environmental and economic considerations into sustainable environmental management.

Using geopolymer to minimise metals leaching from brown coal fly ash

Fly ash is generated from combustion of brown coal in power stations. The majority of fly ash is removed by electrostatic precipitators (ESP) and finally disposed into the landfill as prescribed wastes. A method was studied to add clay materials to the brown coal fly ash in order to form the so-called geopolymer network, which is effective at stopping the metal contents from leaching, and have minimum impact to the environment. The experiments were conducted parallel on leached fly ash and dry precipitator fly ash. The ratios of fly ash and added clay materials were varied to determine the effects of different compositions on leaching rates. Both X-ray diffraction analysis and scanning electron microscopy images showed that as the percentage of fly ash was increased, the formation of geopolymer is reduced. Eighteen metals and heavy metals were targeted during the leaching tests and the leachate samples were analysed using ICP-AES and ICP-MS. It was found that the reduction of metal leaching was achieved by adding up to 60% of fly ash to form the geopolymer like structure. Significant reductions were observed for calcium, strontium and barium. Leached fly ash achieved better stabilisation than dry precipitator fly ash for major elements. It's hard to quantify its effects on trace metals leaching due to their ultra low concentration in the fly ash. The samples spiked with trace metals of lead, zinc, mercury and barium showed remarkable reduction in leaching.

Visualisation development for building demolition planning

Demolition has recently been more concerned with the potential damage to the environment by its generated wastes. Waste exchange is apparently the main means by which the problem is currently dealt with. There is little or no consideration on wastes during the planning or designing stage. By utilising a knowledge system and visualisation technologies, a waste management plan can be integrated into the 4D model so as to effectively promote the interactions between demolition waste demanders and the demolition designer. As a result, the 4D visualisation provides not only the graphical schedule for the demolition process, but also the waste handling plan and waste production schedule. This research aims to analysis the integration technology of a waste management plan and the 4D visualisation model for a demolition project and to discuss the related technical and management issues. The integrated demolition visualisation enables to facilitate waste handling during the demolition processes thus to achieve environmentally friendly demolition.

Salvage material logistics management for building demolition project

Building demolition imposes substantial environmental impacts. In particular, large amount of demolition wastes are disposed to landfills. A solution to ease the situation is to maximally reuse and recycle waste building material. Management philosophies such as Just-in-time are applied into demolition project management in order to promote reuse and recycling of demolition wastes. Transportation logistics, widely applied in the manufacturing industry, is ideal to be adopted into demolition projects to optimise waste material production, inventorying, and transportation. In particular, it enables right types and amounts of dismantled building materials to be transferred to right location, and at right time, as required by material demanders. Consequently, waste reuse and recycling can be facilitated. Furthermore, logistics management helps the demolition project team to reduce cost, shorten project duration, and satisfy material demanders. Transportation planning concerns thorough preparation technically and managerially on the demolition site for transportation activities. Information exchange is playing a significant role in delivering and sharing information among project participants, including building owner, demolition project team, potential material demanders, and transporters. This research paper aims to identify the role of transportation logistics in a building demolition project and to analyse inventory control, transportation, and various technical aspects of logistic management for demolition wastes.

Determination of astaxanthin steroisomers and colour attributes in flesh of rainbow trout (Oncorhynchus mykiss) as a tool to distinguish the dietary pigmentation source

The presence of carotenoids in animal tissue reflects their sources along the food chain. Astaxanthin, the main carotenoid used for salmonid pigmentation, is usually included in the feed as a synthetic product. However, other dietary sources of astaxanthin such as shrimp or krill wastes, algae meal or yeasts are also available on the market. Astaxanthin possesses two identical asymmetric atoms at C-3 and C-3' making possible three optical isomers with all-trans configuration of the chain: 3S,3'S, 3R,3'S, and 3R,3'R. The distribution of the isomers in natural astaxanthin differs from that of the synthetic product. This latter is a racemic mixture, with a typical ratio of 1:2:1 (3S,3'S:3R,3'S:3R,3'R), while astaxanthin from natural sources has a variable distribution of the isomers deriving from the different biological organism that synthesized it. The high-performance liquid chromatographic (HPLC) analysis of all-trans isomers of astaxanthin was performed in different pigment sources, such as red yeast Phaffia rhodozyma, alga meal Haematococcus pluvialis, krill meal and oil, and shrimp meal. With the aim to investigate astaxanthin isomer ratios in flesh of fish fed different carotenoid sources, three groups of rainbow trout were fed for 60 days diets containing astaxanthin from synthetic source, H. pluvialis algae meal and P. rhodozyma red yeast. Moreover, the distribution of optical isomers of astaxanthin in trout purchased on the Italian market was investigated. A characteristic distribution of astaxanthin stereoisomers was detected for each pigment sources and such distribution was reproduced in the flesh of trout fed with that source. Colour values measured in different sites of fillet of rainbow trout fed with different pigment sources showed no significant differences. Similarly, different sources of pigment (natural or synthetic) produced colour values of fresh fillet with no relevant or significant differences. The coefficient of distance computed amongst the feed ingredient and the trout fillet astaxanthin stereoisomers was a useful tool to identify the origin of the pigment used on farm.

Drop-out from parenting training programmes : a retrospective study

Objective: Parent training programmes are a well-established treatment approach for children and adolescents with disruptive behaviour disorders. However, dropout from treatment is a common problem that confounds research on the efficacy of this approach, and wastes important mental health resources. This study sought to further our understanding of the reasons why parents drop out of parent training programmes.

Method: Nine parents of children with disruptive behaviour disorders who had dropped out of a parent training programme were interviewed to investigate why they discontinued the programme.

Results: Parents who dropped out of treatment believed that their children were more difficult than other children with the same disorder and may have been better suited to a child-focused intervention. The parents themselves had very stressful lives, with the majority being single mothers with little support. Dropout parents also had difficulty with the group context and putting strategies into place. Practical concerns included parking, timing of session and the length and number of sessions.

Conclusions: The findings are discussed in terms of what modifications can be made to these programmes to increase retention.

Folding history back onto itself

The history of artists working with the moving image constitutes a substantial dialogue with technology. The ability to construct a complex visual narrative from disparate visual material is a developed skill that is the product of such an evolving dialogue with technique. The use of found and stolen images and their re-processing within such an ‘experimental’ practice can be experienced as transforming the originating material and emphasizing aspects previously hidden. Such ‘shock tactics’ performed on historic material will be examined in the film work of Peter Tscherkassky (Dreamwork Austria 10 minutes 2001) and Martin Arnold (Alone: Life Wastes Andy Hardy Austria 15 minutes 1998). The traumatic effect of these films will be examined in relation to Maya Deren’s ideas of ‘vertical’ and ‘horizontal’ editing and Chris Brewin’s neurological research into traumatic remembering which proposes the interaction between two types of memory systems: SAM (Situational Accessible Memory) and VAM (Verbally Accessible Memory).

Experimental study of abattoir wastewater treatment from an economic perspective

The most cost effective treatment scheme for effluent from Midfield Meats, an abattoir in Warrnambool, Australia, was evaluated via a series of laboratory and commercial scale experiments. Effectiveness was measured in terms of suspended solids (SS) and biological oxygen demand (BOD) reduction. Economic assessment was based on predicted reduction in trade waste charges versus infrastructure and running costs. From the range of potential treatment technologies, those deemed most appropriate for trialling included pre-screening, sedimentation, coagulation and flocculation treatment and dissolved air floatation (DAF). Prior to evaluation of treatment types, flow, loads and contaminant characterisation of the waste streams was conducted to aid in selection of treatment type and capacity. Prescreening was found to be the most cost effective, followed by sedimentation, coagulation and flocculation treatment and finally DAF. The most economical treatment scheme that satisfied the requirements of Midfield Meats included a combination of prescreening and sedimentation. DAF and coagulation and flocculation treatment satisfactorily treated the wastewater, however were not cost effective under the current trade waste agreement.

Clinical waste management in Victorian hospitals

This project for the Doctor of Technology provides a significant contribution to the understanding of healthcare waste management in Victoria and worldwide. The thesis describes approaches to enable healthcare facilities to identify factors that contribute to waste generation and resulting impacts on the environment in order to reduce them.