Goen Ho

The Woodman Point WWTP experiences excessive hydrogen sulfide (H2S) levels in biogas from anaerobic digesters. It currently employs an iron-based chemical oxidant gas scrubber to remove H2S from the biogas. The use of this scrubbing is expensive as well as labour intensive. Direct dosing of the anaerobic digesters with ferric chloride (FeCh) can control H2S emissions. However, chemical is expensive. This study aims to investigate the feasibility of using pickle liquor as an economic form of iron salt to control H2S emissions at Woodman Point WWTP...

Perth, Western Australia’s largest city is under increasing pressure to implement a more sustainable means of water supply and use. The coastal city is expanding rapidly in both population and geographical size (EPA, 2005), while annual rainfall is variable and gradually decreasing (WC, 2005). On top of the supply issues Perth is continuing to implement a centralised approach to wastewater sanitation, which combines many wastewater streams before treatment and disposal to ocean outfall (EPA, 2005). This creates an open cycle system that has many sustainability issues including inefficient use of potable water supplies, loss of freshwater resources and nutrients, pollution of the receiving water bodies, as well as the need for high energy infrastructure (Ho and Anda, 2004). In response to Perth’s water supply concerns the Western Australian Government implemented a State Water Strategy in February 2003. Part of this strategy was to create a Premiers Water Foundation to support research and development projects that investigate water conservation and reuse. A project titled “Demonstration of Decentralised Wastewater Recycling in Urban Villages” was funded by the foundation and aims to achieve a number of demonstration projects and research studies. This technical report is the second of three reports within Premiers Water Foundation project and is focused on technical requirements associated with decentralised wastewater recycling. The aim of the research study is to investigate the technical requirements and technologies (technical elements) associated with the successful implementation of an urban village wastewater recycling system within the PMR, for which a model can be formulated to create reliable management systems and improved protection of public health and the environment.

Wastewater is often considered to be a source of public health problem and to be disposed of rather than considered as a resource. The choice of treatment system is usually governed by disposal strategy rather than reuse options. Domestic sewage generally consists of wastewater produced from the toilet, kitchen sink, bath, shower, washbasin and laundry. Toilet waste, which makes up 25 to 30 percent of the flow, is referred to as black water, while the rest of the wastewater is referred to as greywater. The blackwater contains the major portion of biochemical oxygen demand, suspended solids, bacteria and nutrients. So if the black water is treated separately then the treatment of greywater alone becomes easier and less complicated. Greywater reuse is widely supported by the community in Australia and promoted by researchers. However regulatory authorities have not given permission for greywater reuse. This paper illustrates a few case studies of greywater reuse trials following treatment of the greywater. The reasons for greywater reuse to be permitted by the regulatory authorities are articulated. In the future greywater reuse should be encouraged, and excess payment may be imposed if the greywater is to be treated by a municipality. This paper discusses the different treatment processes being developed to treat greywater successfully. Development of these methods and successful completion of the trials are necessary to develop public confidence to encourage greywater reuse. Present status of the methods and practices with direction for possible future developments are discussed in the paper.

Biosolids originating from wastewater treatment plants contain human pathogens, including Salmonella, which may present a health hazard to the general public. Composting is commonly used as an effective means of stabilising wastewater Biosolids and reducing pathogens to very low levels. However, it has been shown that under certain conditions Salmonella can regrow in previously composted Biosolids. The main aim of the research was to access the importance of indigenous microorganisms in the suppression of Salmonella regrowth in composted Biosolids. In addition, the effect of compost maturity on the pathogen regrowth potential was evaluated.

The purpose of this project was to develop a compact, solar powered desalination unit that would not only provide fresh drinking water for remote communities, but do so with little attention or maintenance. It follows from Project E202 in which a pre-production prototype unit was constructed. The Project team recognised that although Reverse Osmosis is the leading technology in the World for brackish water desalination, it is prone to fouling and failures of the technology are common. The development methodology has been driven by the need to reduce the risks of fouling. Accordingly, low recovery ratios are used at reasonably low pressures. The energy recovery system not only makes the low recovery ratio regime economic in terms of energy use, but also facilitates fully automatic start-up and shut-down as well as self-regulation during fluctuating insolation levels. The production units that have been produced differ from the preproduction unit of Project E202, in that a single cylinder system has been adopted and the valving has been incorporated into the piston head and so is completely internal. While the single cylinder arrangement reduces the efficiency of the unit, it dramatically simplifies construction and reduces cost, while the internal valving has all but eliminated the valving slip that plagued Project E202. Three units were produced with recovery ratios 25%. The preferred model, the 16% recovery produces 620mL per minute of fresh water from sunny winter conditions in Perth.