Sustainable Waste Management by Vermiculture: Design and Management Procedure

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Vermicomposting and vermifiltration are natural waste management processes relying on the use of worms to convert organic wastes to stable soil enriching compounds. Both activities of on-site wastewater management and domestic organic waste management can be accommodated through these processes in a sustainable manner. Sustainability can be achieved through the accelerated cycling of nutrients though a closed cycle whereby waste products are put to productive end use. This paper provides an overview of the system characteristics of management systems utilising vermiculture, the associated methods necessary to manage wastewater and the regulatory framework surrounding such activities. This paper provides the background to the management of domestic liquid and solid organic waste in mainstream society, the regulations that need to be observed in the planning and design of waste management systems, the characteristics of vermiculture, and then 3 case studies of on-site waste management systems that utilise vermiculture: vermicomposting toilets, vermifiltration, and sludge stabilisation. This paper will a) describe vermiculture as a means of on-site sewage treatment; b) review regulatory developments; c) describe case studies of vermicomposting and vermifiltration; d) and explain the broader design approach that needs to be applied with greywater reuse. The paradigm governing wastewater management has focussed on the pollutants in the wastewater and disposal as the solution. It relied on centralised water supply, sewerage and drainage systems with up to 85% of costs incurred in piping and pumping. This paradigm was developed on the Thames River in the last century and its appropriateness for the vast dry continent of Australia has been questioned (Newman & Mouritz, 1996) as has the transfer of these expensive centralised systems to developing countries (Niemczynowicz, 1993) and Australian remote indigenous communities (Race Discrimination Commissioner, 1994). Indeed, the arguments for abandonment of this paradigm in favour of one which cycles nutrients and resources for sustainability are perhaps now as evenly matched against the status quo as they were in the last century when the 'water carriage' lobby narrowly defeated the 'dry conservancy' lobby (Beder, 1993). The latter lobby then also sought separation at source with reuse of dry and liquid products for agriculture albeit with much less scientific basis than that available today. Goodland and Rockefeller (1996) proposed three general principles to enable the passage of the new sustainable paradigm: a) cease expansion of sewers and commence decommissioning them; b) promote on-site recycling systems that avoid pollution of water resources; and c) charge the true value of water. In Australia today there is little evidence that (a) is underway in urban centres; however (b) is well underway; and there is certainly discussion of (c) in the prevailing climate of economic rationalism. The focus of this paper is on-site recycling systems. In assessing the ecological sustainability of nutrient and hydraulic loading rates with on-site effluent treatment systems, Gardner et al (1996) explained that for septic tank systems allotment sizes of up to 1 hectare may be required for a single household. However, for transpiration and aerobic treatment systems the area could be considerably less with up to 4,000 square metres being required. Currently, septic tank systems are in use on lot sizes as small as 600 square metres. Reuse of wastewater occurs most effectively with on-site (localised) or small-scale treatment systems. A major study of Perth's wastewater management (WAWA, 1994) made it clear that it was not possible to reuse all the effluent from centralised treatment plants in the sewered suburban sprawl of Perth - there simply was not enough land for nearby broadacre application. Thus to achieve the goal of total reuse the involvement of a local community in the urban situation would have to be enabled and reuse options in the local context agreed upon. In sewered areas greywater reuse can still be implemented on-site. Greywater or sullage is effluent from the bathroom, washbasin and laundry, and for primary systems should exclude kitchen sink wastewater as it carries oils and high BOD. The more concentrated blackwater (from the toilet) can still go to the sewer along with kitchen effluent. In unsewered areas the blackwater can be treated separately or dry vault composting toilet systems can be utilised. Greywater reuse can result in cost savings (to both the consumer and water utility), reduced sewage flows in sewered areas, and potable water savings of more than 40% when combined with sensible garden design. This paper will a) describe vermiculture as a means of on-site sewage treatment; b) review regulatory developments; c) describe case studies of vermicomposting and vermifiltration; d) and explain the broader design approach that needs to be applied with greywater reuse.

Keywords: Waste Management, Vermiculture, Sanitation, Vermifiltration
Stream: Environmental Sustainability
Presentation Type: Paper Presentation in English
Paper: A paper has not yet been submitted.

Dr. Kuruvilla Mathew

Honourary Research Fellow, Murdoch University, Department of Environmental Science
Division of Science and Engineering, Murdoch University

Perth, Western Australia, Australia

Dr Mathew has his first degree in Physics and Engineering. He has completed a Masters course in Public Health Engineering in India, and a Masters program in Environmental Engineering in Netherlands. He completed his PhD at Murdoch University, Western Australia, on 'Recharge of Secondary Sewerage'. He worked as Academic Staff at Murdoch University for 25 years, and retired as Director of Environmental Technology Centre. At present he is working as Honourary Research Fellow at Murdoch University.

Dr. Martin Anda

Senior Lecturer, Department of Environmental Science
Division of Science and Engineering, Murdoch University

Perth, WA, Australia

Dr. Jaya Nair

Deputy Director, Envioronmental Technology Centre, Division of Science and Engineering, Murdoch University
Perth, WA, Australia

Robert Hughes

PhD student, Department of Environmental Science
Division of Science and Engineering, Murdoch University

Perth, WA, Australia

Ref: S08P0191