Innisfail Sewage Treatment Plant and associated pump stations
The facility is located on the western bank of Ninds Creek about 4.5 km east of the centre of Innisfail, and about 2.7 km upstream of the junction of Ninds Creek with the Johnstone River.
Events of Non-Compliance in the year 2000 included:
• 41 recorded pump station overflows in the first half of the year, 29 of which were infiltration overflows and the remaining 12 other types of overflows.
• Exceedance of the short term limit from Biological Oxygen Demand
• A spill at the plant caused by the top of a non return valve failing
Site Improvements for Environmental Compliance identified in 2000 included:
• Construction of a new sludge storage area for control of the leachate.
• Adjustment of the hypo chloride storage and pumping facility
• Cleaning of the contact tank to control the influence on BOD, DO and Faecal Coliform readings.
• Trade waste septage receival point completed and operational
Nutrient Outputs from the Innisfail STP
A report compiled by Heather Hunter of DNR suggests that the STP is one source of nitrogen (N) and phosphorus (P) discharged to the Johnstone River Estuary from Ninds Creek. Rough estimates were calculated using per capita loadings in sewage effluent of 12 g/day of N and 2.5g/day of P and annual STP discharges from a population of 9000 were estimated as 39 tonnes of N and 8 tonnes of P. These loads are equivalent to <2.5% of the estimated loads of N and P discharged annually from the catchment, and are thus relatively minor at a catchment scale, compared with non-point sources of N and P. Nevertheless, the STP discharge is likely to be a more significant nutrient source during dry weather conditions, when stream flows are relatively low.
JSC Motor Vehicle Workshop
Council's Motor Vehicle Workshop is operated by Council for the purposes of maintenance and repairs to Council vehicles and mechanical equipment. The workshop is located in Clare St Innisfail, in a predominantly light commercial / residential area. It is situated on the northern bank of Bamboo Creek, and within 200 m of the South Johnstone River.
Site improvements for Environmental Compliance identified during 2000 included:
• Installation of a control system for handling waste.
• Filling of internal stormwater drains to prevent contamination to external stormwater.
• Completion of monthly inspection checklists.
Issues during 2000 included;
• A spill at the washdown bay resulting in kerosene and bitumen being spilt onto the ground beside the facility.
• Training of staff on maintaining oil separators.
• New oil storage and distribution system installed.
Innisfail Water Treatment Plant
The water treatment plant is located on the Palmerston Highway about 5 km west of Innisfail. The predominant land-use in the area surrounding the WTP is sugar cane, cattle and residential.
Exceedances of licence limits in the year 2000 included aluminium levels in effluent. The source of the aluminium was from the plant processes and it is anticipated that when the full settling process is carried out, toxicity levels will be reduced.
Mission Beach Sewerage
Consultants were engaged in May 1999 to investigate sewerage options for the Mission Beach area. Based on the outcomes of environmental and engineering studies, and feedback from the community consultation program, future options for sewage treatment and disposal are:
'Do-nothing' - This option involves the continued use of existing on-site effluent treatment systems. The 'do-nothing' option is not recommended.
• Bacteria and nutrient limits currently exceed the environmental and health criteria in some areas.
• On-site disposal is not suitable for many sites due to their limited area, and water logging of soils.
• Septics do not remove nutrients or bacteria. As a result approximately 22,800 kg/year nitrogen, 4,600 kg/year phosphorus and substantial bacterial loads are being released to the environment.
• Modelling predicts that, as population grows, ammonia and bacteria levels will exceed guidelines
• The amounts of nutrients being released to the environment should not be significant enough to impact on the Great Barrier Reef, however impacts on the local environment may be considerable.
• The high rainfall and high water table hinders the efficient operation of septic systems.
Upgrade existing on-site systems - This option involves the upgrading of existing on-site systems to include nutrient and bacteria removal mechanisms.
• There are several treatment systems capable of removing nutrients from sewage. Nitrogen release would be reduced to approximately 9,000 kg/year and phosphorus to 2,700 kg/year.
• This option removes most bacteria from sewage effluent and reduces potential risks to human health.
• This option is not suitable for sites that have a high water table or where there is a limited disposal area.
• This option is outside of the normal SCAP funding range.
• The set-up and operational costs for this option are higher than for other options.
Centralised sewerage system - This option involves the construction and operation of two sewage treatment plants and a sewage collection network.
• The cost for the least expensive central sewerage system was $15.2 million ($13 million without house drains) and $300,000 per year to operate.
• If SCAP funding of $10.8 million is provided, the annual rates per dwelling would be $400.
• If SCAP funding of only $8.6 million is provided the annual rates per dwelling would be $400 and the initial cost of installation (household connection) to owners would be approximately $2,000.
• This option would result in a very high removal of nutrients. Nitrogen in sewage effluent would be approximately 1,000 kg/year and phosphorus 230 kg per year. This option would eliminate almost all bacteria from sewerage effluent.
• Disposal of effluent using the irrigation and groundwater injection methods need further investigation.
The current preferred option for Mission Beach Sewage is piping the effluent to Tully for treatment in a purpose built plant or a plant that will treat both Tully and the Mission Beach effluent.
