June 2003,
Environment Australia
13 Advanced Biological Treatment of Septic Sludge from Residential Properties
Many rural and regional communities in Queensland as well as a high proportion of residential blocks in the urban fringe are unsewered. Septic tanks, in combination with underground effluent trenches, are commonly used in such cases for on-site wastewater treatment and disposal. However, sludge that accumulates in the septic tank has to be removed regularly to ensure continued proper functioning of the septic wastewater treatment system.
Sludge that is collected from residential septic tanks is typically disposed of in soil trenches or at landfill sites. This practice however can have serious negative environmental effects, particularly ground water pollution. This problem became evident over the last few years in the Eastern Downs region. The disposal of septic waste at the Crows Nest landfill had to be stopped when it became evident that leachate from the landfill threatened Toowoomba's water supply and Clifton Shire Council observed a marked improvement in groundwater quality after disposal of septic waste was stopped at its landfill site. Septic waste from both shires is now delivered to Toowoomba's wastewater treatment plant. This disposal option resulted in a considerable increase in service charges residents have to pay to have their septic tank emptied, and resulted in some disquiet in the community.
These events, which caused significant problems for Crows Nest Shire coincided with the development phase of the on-farm composting project. Council had asked whether this aspect of rural/regional waste management could be included in the project. This was agreed to and the sub-project 'Advanced Biological Treatment of Septic Sludge Collected from Rural Residential Properties' was incorporated into the overall project plan. The industrial partner was Town & Country Septic Services whose owner was very interested to find an alternative to disposing of residential septic waste at Toowoomba's wastewater treatment plant, which would allow him to reduce service charges to his clients.
However, with hindsight it seems that this sub-project was not 'under a good star'. It was plagued by unfortunate, even tragic incidences and situations and unfortunately relatively little progress was made during the entire project period. Occurrence and outcome of such events were beyond the control of the project manager. A brief chronological overview of developments within this sub-project is provided below.
- After the Expression of Interest for the project had been lodged, the owner of Town & Country Septic Services and his son died in a tragic accident in February 2001. This was before co-operational agreement regarding Town & Country's involvement in the project was reached. Talks and negotiations with the widow regarding support for the project were difficult and lengthy, even though in the end support was granted for the proposed activities.
- The widowed owner of Town & Country Septic Services was not in a position to continue with the business. In November 2001 she sold Town & Country Septic Services Pty Ltd. After briefings and discussions, the new owners agreed to honour their predecessor's commitment to the project and to cooperate.
- The new owners of now Town & Country Industries Pty Ltd had also local business interests in earthmoving and land development. While this appeared beneficial for the project from various aspects, it proved a heavy burden. Unfortunately, the working relationship between Town & Country Industries and Crows Nest Shire Council was very difficult due to disputes over land development and various other issues, including environmental matters.
- In March 2002, with only ten months left in the project it became clear that it would be difficult to conduct a meaningful research and development project within the framework of the existing project. Consequently, a funding application to the Advanced Wastewater Treatment Technologies Scheme [AWWT] (administered by the Queensland Department of Local Government and Planning) was considered.
- After considering various potential treatment and re-use sites on land owned by the proprietors of Town & Country Industries, a suitable site was found. Site planning and talks with council had already begun when the landowner took the opportunity to sell the land in May 2002.
- Despite all odds, Crows Nest Shire Council was approached to consider a joint venture in which council would provide appropriate land and Town & Country would build the pilot treatment facility. However, due to its experience in the past, council was unwilling to enter into such an agreement with Town & Country Industries.
- In the meantime a 'quasi' draft proposal for a 2½ year R & D project under the AWWT scheme was developed. In October 2002, Cambooya Shire Council, located on the southern outskirts of Toowoomba, was approached to see whether they were interested in being involved in the proposed project. The response was positive.
- A change of staff at Cambooya Shire Council in February 2003 revealed that council had no records of the proposal and of previous contacts regarding this matter. New staff had to be briefed and introduced to the proposed project. In May 2003 council decided not to support the proposed development project, even though it acknowledged that it had merit.
The project proposal and a project summary for Cambooya Shire Council that addressed mainly licensing issues, risk management aspects and proposed financial and contractual arrangements are provided in Appendix V.
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