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Applied Environmental Health ~ Wastewater Management |
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Wastewater Management Seminar 2003 |
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The WWMS (DHS) recently held the 2003 On-site Wastewater Seminar at the Murray Bridge Local Government Centre. We received registrations from 70 participants from Local Government, State Government, Industry and Flinders University Environmental Health students. Dr Rod Givney, the Director of the Communicable Diseases Branch of the DH opened the seminar and this was followed by a number of interesting and informative presentations. An outline of and direct links to the presentations (where available) follow:
Title: INSTALLATION OF ONSITE SYSTEMS
An overview of the current on-site WW code was presented.
Title: ONSITE WASTEWATER REVIEW UPDATE A code review is currently being undertaken by the WWMS DH in consultation with key stakeholders. The Code was last reviewed in 1995. As Councils have gained more experience and expertise in the area of on-site wastewater systems and most states and territories are moving toward the adoption of Australian & New Zealand Standards a necessity to review the current code was recognised and implemented. The Code review workgroup has completed an initial comprehensive consultation and will seek to gain Ministerial support to proceed, comments from the P&EH Council and then prepare first drafts of the Product and Installation Codes for wider consultation. Link: (1) PPT
Title: POTENTIAL HEALTH RISKS FROM GREYWATER This presentation outlined the health issues associated with greywater reuse. David discussed a definition of greywater, the associated risks by type of grey water (bathroom, laundry and kitchen); application methods and end use. David also discussed the typical microbiological loading of greywater by type. He concluded that for on-site systems the concentration and range of hazards would depend on household management. Restricting methods of application and types of use can reduce risk but for on-site systems this will rely on household management. Systems need to be robust and designed to involve a minimum of maintenance. Centralised management systems are best. Link: (2) PPT
Title: GREYWATER SYSTEMS & TREATMENT OPTIONS This presentation included an introduction to the design, operation and maintenance of greywater systems. These systems are expected to increase in popularity. A description of reed bed systems and also greywater (bath and laundry) diversion devices was given. The issues relating to required plumbing changes for fitting the devices into a dwelling and sub surface disposal of the resultant effluent provide scope for plenty of discussion. A number of slides showing installed devices were shown. The knowledge and expertise of SA Water was also of great assistance during this session. This also stimulated further discussion over the remaining days on the proposal by DH to enable councils to approve greywater diversion system installations in their respective areas.
Title: OPERATION OF AEROBIC WASTEWATER SYSTEMS Tony presented aerobic wastewater systems and discussed how they work, including primary and secondary treatment, microbial action, clarification, disinfection and pump-out. Link: (5) PPT
Title: WASTEWATER PLANNING MANAGEMENT ISSUES Neville Pash & Gerald Thompson talked about planning issues from their respective departments perspectives. Neville spoke about a number of issues including development of PARS, planning considerations using the examples of Mount Crawford and Crozier Hill and also discussed the definition of a watercourse. Neville also gave some interesting examples of unusual scenarios within planning including the changing of the alignment of a watercourse and discussed assessment principles. Gerald Thompson then discussed planning from an EPA perspective. He presented a number of issues that EPA face including: up to 44% failure rates of existing systems and their environmental impacts; planning rules for new lots and EPA requirements; development potential for Water Protection Areas and solutions to the problems encountered.
Title: SITE AND SOIL ASSESSMENT FOR ON-SITE DOMESTIC WASTEWATER MANAGEMENT Day 2 began with an interesting and extremely informative presentation from Richard Atkinson titled “Site and Soil Assessment for On-site Domestic Wastewater Management” with reference to AS/NZS 1547:2000. Richard presented information about the problems associated with the management and disposal of on-site wastewater and also the solutions to address them. He then discussed assessment methods, who should do assessments, site inspections, detailed site and soil evaluation and the properties of soil. Richard also spoke about the role of Local Government, what happened to the percolation test and South Australian soils. He stated that recommending a suitable domestic wastewater management system is an important task and that AS/NZS 1547 provides detailed procedures for undertaking site and soil assessments. Richard’s presentation was followed by a field trip to various sites around Murray Bridge including two on-site system installations, a nutrient reduction system, Murray Bridge WWTP sludge lagoons where Tony Catalano explained the use of the innovative sludge socks, and the Monarto Zoo. Richard gave some practical examples of soil assessment in the field and answered questions on-site and in transit.
Title: WASTE CONTROL SYSTEMS THE CITY OF ONKAPARINGA’S APPROACH Tim presented installations from a Council perspective. Tim’s insight from the position of EHO and former plumber was invaluable. He discussed the application process, assessment and gave examples of applications that had failed to meet certain criteria such as setback distances not being met; poor drain design; and proposed soakage under a driveway. Tim also covered common issues encountered at Local Government associated with installations. He finished his presentation with a proposal to have underfloor plumbing self-certified, the introduction of a $500 bond to owners that would be refunded as soon as the work had been completed, inspected and approved, and greater use of innovative designs. Link: (9) PPT Link: (9a) PDF download (262k)
Title: IRRIGATION REQUIREMENTS FOR TREATED WASTEWATER
Tony Farror discussed irrigation. This presentation centred on shallow sub surface irrigation of treated wastewater and featured the requirements of AS 1547 2000 " On Site Domestic Wastewater Management" which includes a section on systems such as these.
Link: (10) PPT
Title: NEW TRENDS IN WASTEWATER MANAGEMENT Mehlika Kayaalp discussed new trends in wastewater management including septic tank filter, vacuum systems, and presented overseas trend including the separation of wastewater, black water, yellow water, excreta treatment, and reuse. It seems that, especially in Western Europe, very high level of treatment is required for reuse of wastewater. Link: (11) PPT
Title: IS IT IMPORTANT OR ARE WE JUST BEING PEDANTIC BY COMPLYING WITH THE STANDARDS? Heather gave an interesting talk with respect to percolation of effluent into the soils surrounding the soakage trench. Heather also discussed the various characteristics that the test soils exhibited in relation to effluent flows. OPEN FORUM PANEL DISCUSSION
The question and answer session after lunch was an opportunity for delegates to ask questions and discuss issues raised during the course of the seminar with panel members consisting of Mehlika Kayaalp Tony Farror, Neville Pash and Kathy Thomas
(DH WWMS), Heather Treloar (City of Murray Bridge), and Tim Woods (Onkaparinga Council).
While a definitive answer could not be found for all these points there were some very useful and interesting discussions on all of these issues.
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