2016-07-12 - Item 14 - Att 1 - Effluent Disposal Planning Study

          6 plants had insufficient chlorine levels, and
          7 mechanical faults were found. ( broken air blowers, pumps and alarm systems)

For land application areas 16 were defective. The issues were overgrown vegetation and
inappropriate ground coverage, signs not being in place and faulty sprinklers. There was no record
of failures to subsurface irrigation although anecdotal instance and past complaints suggest that
failures are common over the life of the system (15 years).

There was one treatment plant which had a sand filter that had completely failed and needed
replacement.

Audit Conclusions
The audit reveals there are extensive faults with on-site waste water treatment plants and their
land disposal systems. The issues vary in seriousness and most faults can be prevented or fixed if
the correct servicing procedures are adhered to and proper maintenance of systems is carried out.
Some owners and renters of properties do not maintain their treatment plants properly. During
trials to obtain a Chief Executive approval the influent into treatment plants is meant to be within
certain parameters to ensure the system is working at its optimal level. The influent from private
households is not always within the correct parameters. Products such as bleach, dishwashing
liquid, hair dyes and certain medications can have a negative impact on bacterial growth within the
plant. Overloading from high water usage or over population of dwellings can also have a
detrimental effect on the systems.

Faults regarding surface irrigation are usually minor and can be rectified at minimal cost but if there
are faults with subsurface irrigation it can be costly and hard to fix. High total suspended solid
levels are a major cause of the failure. (It is rare to find a system that disposes of treated effluent
from treatment plants into trench systems.)

Faults regarding the treatment plants can be costly and hard to fix depending on the system.
Pumps and blowers (blowers are in aerated treatment plants) have a lifespan and will eventually
fail. Overworking of pumps from blocked land application areas or high work rates due to high
flows into the treatment facility are some common reasons for failure. Sand filter systems can get
blocked and are very costly to repair. High suspended solid levels is the main reason for failure
and this can occur when systems are not pumped out when the sludge levels are high or an
overloading of the system occurs (eg. too many people residing in the residence, greater than 10
equivalent people)

Causes
          Residents and owners of properties are not aware of the maintenance requirements for
           treatment plants,
          Owners of properties are under financial pressure and are not able to fix problems with
           treatment plants,
          Service agents are not servicing the treatment plants properly or are under pressure
           from owners due to owners not having enough money to fix problems, and
          Some systems are not favourable for certain areas and require a different approach to
           future systems in such areas.

Solutions
        Acknowledge new plumbing legislation is likely in 2016 and prepare to respond as
          necessary,
        Consult with industry to discuss requirements and possible solutions to issues,
        Continue with on-going audit program to monitor treatment plants and use the
          opportunity to inform owners of the risks and their obligations,
        Provide information to the Queensland government on the performance of treatment
          plants to assist in policy development,
        Implement local policies to try to improve the situation and reduce current risks, and


On-Site Effluent Disposal in Noosa Shire 2016                                                  Page 20