Reductions in nutrient discharge from aquaculture through recycling of water utilising floating media and activated carbon filtration

Nutrient discharge into coastal areas, such as the Great Barrier Reef can result in the degradation of coastal ecosystems. For example, excess nitrogen and phosphorus can damage corals through inducing algal bloom and subsequent shading. Excessive phosphorus can further weaken coral skeletons making them susceptible to damage. Land based industries such as aquaculture can contribute to such problems. This study set out to develop a system whereby water from aquaculture can be constantly reused resulting in minimized waste discharge. A three-stage filtration system utilizing floating media and activated carbon was designed to harness bacterial processes that could reduce both particulate and dissolved compounds to the extent whereby approximately 100% reuse of the wastewater became possible. This involved efficient and effective particulate and biological removal mechanisms in both aerobic and anaerobic zones of the filtration system. This design reduced dissolved nitrogen levels by up to 70% and maintained low phosphorus levels, which allowed the reuse of water for the successful culture of barramundi with a survival rate of 97% over 25 days. This pilot scale study demonstrated the potential of reusing aquaculture wastewater from the viewpoint of reducing nutrient input into coastal environments. Future research will refine these processes and assess the performance of the system at several commercial scale applications.

Evaluating the potential for zero discharge from reverse osmosis desalination using integrated processes : a review

Desalination processes used worldwide produce a large amount of waste concentrate, the disposal of which can have significant environmental impacts. As such, there has been research carried out into the development of zero liquid discharge technologies which recognise that the waste concentrate streams contain valuable salts, minerals and water. These technologies include the proprietary SALPROC systems, as well as other integrated systems that use a variety of different technologies for the extraction of salts and minerals from waste concentrates. Research has also been conducted on using forward osmosis as a means of treating the waste concentrate in order to produce additional product water and thus reduce the volume of waste concentrate. This article provides a review of these technologies and evaluates the potential for achieving zero liquid discharge by combining these technologies with conventional desalination technologies into integrated processes.

A cloud of smug over outdoor education : South Park, hybrid cars and environmental morality

In an episode of South Park titled ‘Hey, People, You’ve Gotta Drive Hybrids Already’, Stan convinces townsfolk to buy hybrid cars. This reduces the rate of smog but creates a toxic cloud of ‘smug’. In this paper, I use this parody of eco-correctness to interrogate some of Outdoor Education’s environmental aims. Michel Foucault’s later work on the self, morality and governmentality is used to analyse the production of the [neo- iberal] ‘environmentally responsible citizen’. The possibilities and problems of contemporary citizenship discourse are explored in relation to findings from a longitudinal study of students undertaking a tertiary outdoor and environmental education course.

Contribution of fungi to primary biogenic aerosols in the atmosphere : active discharge of spores, carbohydrates, and inorganic ions by Asco- and Basidiomycota

Spores and related chemical compounds from actively spore-discharging Ascomycota (AAM) and actively spore-discharging Basidiomycota (ABM) are primary biogenic components of air particulate matter (characteristic size range 1–10 μm). Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the forcible discharge of fungal spores may account for a large proportion of coarse air particulate matter in tropical rainforest regions during the wet season. For the particle diameter range of 1–10 μm, the estimated proportions are ~25% during day-time, ~45% at night, and ~35% on average. For the sugar alcohol, mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively discharged basidiospores (ABS), and that the literature-derived emission ratio of about 5 pg per ABS may be taken as a representative average. ABM emissions may account for most of the atmospheric abundance of mannitol, and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter, but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season, and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforest aerosols are consistent with measurements performed at other locations.

Based on the average abundance of mannitol in particulate matter, which is consistent with the above emission ratio and the observed abundance of ABS, we have also calculated a value of ~17 Tg yr−1 as a first estimate for the global average emission rate of ABS over land surfaces. Comparisons with estimated rates of emission and formation of other major types of organic aerosol (~47 Tg yr−1 of anthropogenic primary organic aerosol; 12–70 Tg yr−1 of secondary organic aerosol) indicate that emissions from actively spore-discharging fungi should be taken into account as a significant source of organic aerosol. Their effects might be particularly important in tropical regions, where both physicochemical processes in the atmosphere and biological activity at the Earth's surface are particularly intense, and where the abundance of fungal spores and related chemical compounds are typically higher than in extratropical regions.

Toward higher level abstractions for cloud computing

The general idea of cloud computing is offering computational resources as scalable, on demand services accessible over the internet. However, this new realisation of on demand computing is hindered by the amount of user involvement. Currently, high level abstractions in cloud computing only exist in the form of services. In particular, there is no effective means to publish, discover and finally use required services in clouds. In response, we propose a user level abstraction on top of already available cloud abstraction layers, present its concept using the resources via web services (RVWS) framework and demonstrate its feasibility by simplifying the exposure and use of clusters, a commonly used resource in cloud computing.

Coastal responses to estuarine discharge from intermittently open systems

This thesis is the first study to examine the interaction between estuarine discharge and coastal environments, for intermittent estuaries in Victoria. The study examined water quality, bacteria and seaweed communities and the diet of mussels, concluding that estuarine discharge is an important driver for the productivity of nearshore marine environments.

Establishing trust in hybrid cloud computing environments

Establishing trust for resource sharing and collaboration has become an important issue in distributed computing environment. In this paper, we investigate the problem of establishing trust in hybrid cloud computing environments. As the scope of federated cloud computing enlarges to ubiquitous and pervasive computing, there will be a need to assess and maintain the trustworthiness of the cloud computing entities. We present a fully distributed framework that enable trust-based cloud customer and cloud service provider interactions. The framework aids a service consumer in assigning an appropriate weight to the feedback of different raters regarding a prospective service provider. Based on the framework, we developed a mechanism for controlling falsified feedback ratings from iteratively exerting trust level contamination due to falsified feedback ratings. The experimental analysis shows that the proposed framework successfully dilutes the effects of falsified feedback ratings, thereby facilitating accurate and fair assessment of the service reputations.

Prevention of information harvesting in a cloud services environment

We consider a cloud data storage involving three entities, the cloud customer, the cloud business centre which provides services, and the cloud data storage centre. Data stored in the data storage centre comes from a variety of customers and some of these customers may compete with each other in the market place or may own data which comprises confidential information about their own clients. Cloud staff have access to data in the data storage centre which could be used to steal identities or to compromise cloud customers. In this paper, we provide an efficient method of data storage which prevents staff from accessing data which can be abused as described above. We also suggest a method of securing access to data which requires more than one staff member to access it at any given time. This ensures that, in case of a dispute, a staff member always has a witness to the fact that she accessed data.

Trust ticket deployment : a notion of a data owner's trust in cloud computing

While cloud computing (CC) is a scalable model of shared infrastructure and on-demand computing, it lacks a transparent trust and security mechanism. A data owner (DO) loses control over the data outsourced to a machine in the cloud controlled and operated by a cloud service provider (CSP). This machine is at a location unknown to a data owner. This loss of control over data is further intensified with the lack of managing users' access to the data from practical cloud computing perspectives. In this paper, we introduce a new mechanism of ensuring trust and security in Software as a Service (SaaS) CC. Trust Ticket, with the supporting protocols, is our mechanism that helps a data owner in establishing a link between a CSP and a registered user. In our mechanism, a user first gets registered with a DO before receiving a Trust Ticket and a secret key from that DO. Each Trust Ticket is unique and encrypted. On completing the registration of each user, the DO apprises the CSP of the Trust Ticket. Trust Ticket and secret key are respectively for the registered user's getting accepted to the CSP and having a view of the data owner's data upon a successful verification by the CSP. We have done our experiment in Java network programming by creating an emulated cloud computing framework under the VMware ESXi 4.1 hyper visor based platform. Using the framework, we have evaluated our algorithmic protocol for Trust Ticket. We have also compared our work with prior work. Overall performance of our work is better. We argue that our proposed algorithmic protocol for Trust Ticket deployment establishes a data owner's trust. This trust is established through a data owner's control over data and a registered user, because a registered user is linked with a CSP by a data owner through Trust Ticket.