Regional Sewerage Networks

Chinchilla

Dalby Urban

Jandowae

Miles

Tara

Meandarra

Wandoan

 

 

Chinchilla

The Chinchilla collection network comprises some 4.3 km of rising mains, 43.3 km of gravity sewer mains, 690 manholes and 7 wet well pumping stations:

  • Pump Station A in Boyd Street;
  • Pump Station B in Zeller Street;
  • Pump Station C in Rodger Street;
  • Pump Station D in Cooper Street;
  • Pump Station E in Riverdell Park Estate;
  • Pump Station F in Gaske Lane;
  • Pump Station G in Keating Street.

Sewage from the seven catchment areas is gravity fed to the individual pumping stations from whence it is pumped to a common collection point at Pump Station A before being pumped via a 300mm diameter rising main to the Treatment Plant off Waterworks Road.

The Treatment Plant comprises an Inlet Works with screens and grit removal, primary sedimentation, biological trickling filtration and secondary sedimentation, sludge digestion and sludge drying facilities and lagoons.

Generally the sewage treatment consists of:

  1. Raw sewage flows through an inlet works where screenings and grit is removed before discharge to the primary sedimentation tanks
  2. Effluent from these tanks flows to the biological trickling filter and then to the secondary sedimentation tanks before it is piped to oxidation ponds
  3. Sludge is drawn off from both the primary and secondary sedimentation tanks at regular intervals for transport to the sludge digester
  4. Digested sludge is then air dried in sludge drying beds and disposed off on site
  5. Effluent from the treatment plant is pumped to a neighbouring farm where it is mixed with other water and used for irrigation purposes.

The present scheme will cater for a population of 6,000 EP.

 

Dalby Urban

The Dalby sewerage scheme is a conventional gravity sewerage system.

The Town is served by eight sewerage catchments each of which drains into a submersible sewage pump station.

  • Pump Stations 7 and 8 pump into Pump Station 4.
  • Pump Station 4 pumps into Pump Station 2 whilst Pump Stations 3, 5 & 6 pump into Pump Station 1.
  • Only Pump Stations 1 and 2 pump directly to the treatment plant.

The treatment process consists of:

  • An inlet works comprising bar screens and grit removal channels
  • Two sequential batch reactors which involves aeration, settling and surface skimming (decanting) and disinfection

Sewage treatment is to a secondary standard with biological nutrient removal.

The plant is also able to operate as a conventional flow plant utilizing some of the infrastructure from the old activated sludge plant.

Sludge from the treatment process is digested in an aerobic digester and dewatered by a belt press.

Approximately 30% of the effluent from the sewage treatment plant is used for irrigation of the Dalby Golf Course, Dalby Race Course, and Dalby South State School sports fields.

 

Jandowae

Jandowae Sewerage scheme was commissioned in 1974 and services approximately 95% of the developed town area.

The sewerage reticulation network comprises of sewers 150, 225, and 300mm diameter pipeline. These sewers gravitate to four pump stations, with number 4 pump station being the central collection point before pumping to the treatment plant.

The treatment plant scheme has two wetlands which are alternately discharged upon.

 

Miles

The Miles sewerage scheme was installed in 1964/65.

It has two main catchment areas and two minor catchments around the Industrial Estate and Water Treatment Plant areas.

The existing sewerage infrastructure includes 150mm, 225mm and 300mm diameter reticulation mains. At the lowest point of each of these catchment areas a pump station transfers the sewage.

Pump stations:

  • 2 (Daisy Street)
  • 3 (Industrial Estate);
  • 4 (Water Treatment Plant)

Each pump station is equipped with submersible pumps, transfer sewage into the main reticulation system, from where Pump Station 1 collects all the town sewage and pumps it to the sewage treatment plant.

At the Treatment Plant the sewage flows through a screening chamber and grit channel before flowing into two (2) Imhoff Tanks where a proportion of the sewage sludge (solids) settles out to the bottom of the tanks.

Anaerobic digestion of the sludge occurs over time, after which the sludge is transferred to the sludge drying beds.

The liquid from the Imhoff Tanks, which still contains a certain amount of suspended solids, is transferred to the aerobic lagoons, which further purify the effluent.

There are three lagoons in place and liquid flows from the first pond to the second and then to the third, after which the final effluent is transferred to adjacent property for reuse.

The Miles Sewerage Scheme has a provision, under a license regulated by the Environmental Protection Authority (EPA), to discharge effluent to adjacent land for evaporation and reuse on a tree lot. The site is extensively bounded by a levy bank and there is no discharge from the sewage treatment plant site.

 

Tara

The Tara Sewerage Scheme comprises some 24.78 km of sewer mains, 155 manholes and one wet well pumping station with two pumps each with a capacity of 35 L/s.

Sewage from each catchment area is gravity fed to the pumping station where it is pumped via a 225mm diameter rising main to a treatment plant.

Each treatment plant comprises an Imhoff tank, sludge drying beds, oxidation lagoons and evaporation pans.

Generally the sewage treatment consists of pumping raw sewage through a screen prior to entering the Imhoff tank, allowing solids to settle, and transferring the resulting supernatant liquor into a series of oxidation ponds for further treatment.

Each Imhoff Tank comprises two chambers:

  • The upper chamber provides the necessary sedimentation facility with the settled solids accumulating in the bottom of the tank (lower chamber);
  • The lower chamber promotes biological digestion of the settled solids (known as sludge), which is drawn off as digested sludge to the drying beds and subsequent disposal.

Effluent drawn from the top of the tank is discharged into the first of a series of oxidation lagoons for secondary treatment.

Detention time in the lagoons reduces the biochemical oxygen demand (BOD5), micro-organism concentrations and suspended solids to acceptable levels for further use. The effluent then passes into evaporation pans or ponds for disposal via evaporation.

Effluent from the treatment plant is pumped to the Tara Golf Course, adjacent to the treatment plant, where it is used for irrigation. Unfortunately, due to the high sodium content of the effluent, minimal effluent is actually used for irrigation purposes. Most effluent is disposed of via evaporation.

Sludge is manually drawn from the digestion chamber of the Imhoff tank at regular intervals (typically every three months) for air-drying and disposal on site.

The present scheme is capable of catering for a population of about 1,500 people.

Meandarra

The Meandarra Sewerage Scheme comprises some 10.44 km of sewer mains, 54 manholes and one wet well pumping station with two pumps each with a capacity of 10 L/s.

The Tara and Meandarra sewerage schemes are very similar in nature.

Sewage from the catchment area is gravity fed to the pumping station, in Osler Street, then pumped to the Treatment Plant.

Raw sewerage exiting the rising main is discharged to an Imhoff tank, providing primary treatment. Effluent from the Imhoff tank is piped to oxidation ponds for secondary treatment. From the oxidation ponds, the treated effluent gravitates to a system of four evaporation pans for disposal. All effluent is disposed of via evaporation.

Sludge is manually drawn from the digestion chamber of the Imhoff tank at regular intervals (typically every three months) for air-drying and disposal on site.

The present scheme is capable of catering for a population of about 400 people.

Wandoan

Sewage from each of three catchment areas is gravity fed to the relevant pump stations:

  • Pump station 1 (North Street)
  • Pump station 2 (West Street)
  • Pump station 3 (Lower Hamlyn Street)

each of which is equipped with duty/standby submersible pumps.

From each pump station, the raw sewage is pumped via a rising main to the gravity system which in turn discharges to the sewage treatment plant.

The sewage treatment process consists of screening prior to entering the Imhoff tank, allowing solids to settle, and transferring the resulting supernatant liquor to the next part of the process.

Each Imhoff tank comprises two chambers:

  • The upper chamber provides the necessary sedimentation facility with the settled solids accumulating in the bottom of the tank (lower chamber)
  • The lower chamber promotes biological digestion of the settled solids (known as sludge), which is drawn off as digested sludge to the drying beds and subsequent disposal.

Effluent drawn from the top of the Imhoff tank is discharged to the first of a series of three aerobic lagoons for secondary treatment.

Detention time in the lagoons reduces the biochemical oxygen demand (BOD), micro-organisms concentrations and suspended solids to acceptable levels for further use.

The effluent then passes into a collection pond at the treatment plant. All available effluent is used to irrigate the showgrounds and the golf course.