Council provides these activities to support the health and wellbeing of the community and the environment. Currently Council provides for the continuous collection and transportation of the wastewater from residential and commercial properties of the township of Westport, Little Wanganui and Reefton through underground piping infrastructure and treatment facilities. The rest of the district is serviced by on site disposal system that property owners are responsible for the maintenance of. Council is investigating areas where septic tank systems can be upgraded, whether by including these into the reticulated system or assisting with subsidy applications for communities to upgrade areas of concern to mitigate potential environmental risks.
Why do we do it
Council intends to retain ownership of the sewer systems for the following reasons:
Public Benefi t: The service is deemed to provide a public benefi t. Core Business: The provision of wastewater services is considered to
be a core function.
Exclusivity: The ability to exclude or disconnect properties from the sewer reticulation had economic and public health implications. Public ownership can prevent the sewer system from being controlled in an exclusive manner. Monopoly Supply: The majority of properties have limited disposal
options.
Community Opinion: Generally the public do not favour the privatisation of wastewater services.
For these reasons the objective of retaining ownership of the wastewater system is to use that control wisely and in the best interests of the affected communities.
How we contribute to strategic
goals and community outcomes
This activity supports the following community outcomes.
Community Outcomes How the Council contributes
Safety By providing a sanitary wastewater collection and treatment service
Environment By protecting the environment through the wastewater treatment
Health: By providing a sanitary wastewater collection and treatment service
Education By providing water conservation programmes Economy By meeting commercial wastewater needs and
meeting community needs at affordable costs
How the council performed
Monitoring and reporting of the wastewater treatment plants has been undertaken in accordance with the resource consents.
The composting of biosolids from the wastewater treatment plant at Westport and green waste has continued with preliminary testing of the compost meeting health requirements.
Stormwater that is disposed of in combination with wastewater has resulted in some areas of Westport’s wastewater system not working effi ciently because of overload. This has resulted in residents being unable to use toilet facilities for periods when the system is overloaded. Council has requested modelling of the wastewater system to programme separation and also to provide solutions.
Confi rmation of the modelling is still in progress by the Consultant and capital expenditure is to be carried forward to 2011/2012.
Key performance indicators
What we did What we measured Target Actual
Public Safety:
Provide safe facilities for both the community and the operators
No accidents, injuries or public contact with
SEWAGE Supplying reticulated sewer systems that support public health and operator safety. No accidents recorded (2010: one injury at waste water treatment plant. Number of public health issues attributed to
the wastewater system Maintain zero reports No reports (2010: nil)
No intrusions or injuries Maintain zero reports No intrusions and no injuries arising from intrusions (2010: nil)
System Capacity:
Provide adequate capacity Maintain capacity of existing combined systems
Design all new systems to nationally acceptable standards.
No more than ten overflows throughout the district.
11 of the 16 sewerage overflows occurred on the Carters Beach rising main between Carters Beach and Westport (2010: 9 overflows). These are unavoidable due to inferior pipe being installed in 1995.
As the number of these vary year to year, it is a better option to repair a section of pipe, rather than replace 4km of rising main. No new systems constructed.
System Reliability:
Provide a reliable sewer system To accept sewage from properties virtually
all of the time No more than one blockage per kilometre of pipeline Council has 54 km of sewerage mains and for the 2010/2011 year we had 21 blockages which equals 0.39 blockages per kilometer of pipe. This is less than the target level indicated (2010: 13 blockages, per 0.17km of pipeline). All blockages cleared within four hours Blockages were cleared in accordance with
response times recorded on service requests. No more than 40 blockages in laterals Within the Westport/Carters Beach, Reefton
and Little Wanganui Subdivision sewerage schemes there are over 3,000 property connections (laterals). Over all three sewerage schemes there were a total of 39 lateral blockages that required clearing. This is one less than the targeted level. (2010: 29 lateral blockages)
What we did What we measured Target Actual
Environmental Impact: Provide sewer
collection and disposal with the minimum environmental impact
To comply with resource consent conditions
100%
compliance Reefton Waste Water Treatment Plant (WWTP):
Reefton WWTP consent requires scheduled monitoring 9 times per annum for a variety of analytes at various locations.
The Ponds are monitored for Dissolved Oxygen levels, odours, and a variety of potential visual anomalies. The effluent in the ponds discharge channel is monitored for various analytes including Biological Oxygen demand, Faecal Coliforms, Ecoli, and Total Suspended Solids.
Receiving water quality is also undertaken downstream at the confluence of Cemetery Creek and the Inangahua River. Analytes include Visual clarity of the water, Biological Oxygen demand, Suspended Solids, Unionised Ammonia, Dissolved Oxygen, pH, Water Temperature, Faecal Coliforms, and Ecoli.
Additionally annual monitoring of the sediments in the discharge channel is required on an annual basis. Analytes for this include Arsenic, Cadmium, Chromium, Copper, Mercury, Nickel, Lead, Zinc, and Poly Aromatic Hydrocarbons
Analytes that were in breach of the consent conditions were:
• This happened last year as well, and appears to have no effect on the efficiency of the process. The
cloudiness spontaneously corrected itself.
• While not part of the consent effluent discharges were tested for the same heavy metals. This is in
conjunction with the presence of metals detected in sediments upstream of the plant discharge tends to indicate that the source of the contaminants is not the waste water plant but is from another source located upstream of the plant.
• One Ecoli and Faecal Coliform result at the Inangahua River confluence with cemetery creek breached
the terms of the consent. The effluent quality leaving the treatment plant was tested at the same time as the Inangahua river tests. The excellent results of this discharge testing tended to indicate that additional contamination could be being added to the Cemetery Creek watercourse, by another source other than the treatment plant, at some point along the 600m length between the treatment plant and the Inangahua river
Conveyance Pump Stations:
Large parts of Westports sewer network also double as its stormwater network. This leads to large quantities of rainwater entering the sewer system. Prior to the 2006 upgarde of Westports sewerage system this was not an issue. However the sewerage treatment upgrade required the construction of sewerage pumping stations at the sewer / stormwater outfalls, in order to transport the sewerage to the Alma road treatment plant. It was deemed to be uneconomic and impractical to size the pump stations and the treatment plant to treat this huge volume of additional stormwater. This was recognised in the Westport Waste Water Treatment Plant consent which allows for storm water induced overflows to occur at the 3 outfall sewer pump stations located at Pakington, Rintoul and Roebuck St outfalls.
Stormwater induced overflows are monitored by testing the receiving water quality downstream of the pump station concerned, and recording the dates times and durations of these events. As well as monitoring water quality at two recreational (Marr’s and Shingle) beach locations downstream
Breaches of this condition were noted as:
• Pakington Street - 3 rain overflow transgressions for Ecoli / FC / Enterro • Roebuck Street - 6 rain overflow transgressions for Ecoli / FC / Enterro
• Rintoul Street - 3 rain overflow transgressions for Ecoli / FC
It is noted that as the pump stations are located prior to the treatment plant, that council can only monitor the upstream and downstream contaminant levels, and cannot alter the concentration or dilution or duration
What we did What we measured Target Actual
Environmental Impact: Provide sewer
collection and disposal with the minimum environmental impact
To comply with resource consent conditions
100%
compliance Westport Waste Water Treatment Plant (WWTP):
The Westport Waste Water Treatment Plant consent requires monitoring of receiving waters in the Buller river 9 times per annum. Analytes include Visual clarity of the water, Biological Oxygen demand, Suspended Solids, Unionised Ammonia, Dissolved Oxygen, pH, Water Temperature, Faecal Coliforms, and Ecoli. As well as observing whether any scums, discoloration or odours are present.
The consent also requires monitoring of the effluent quality at the point where it leaves the treatment plant, 9 times per annum. Analytes for this include Biologival oxygen demand, Faecal coliforms, E.coli, Suspended solids, conductivity, effluent volume,
Once per year the sediments in the Buller river are tested for levels of various contaminants, These analytes include Aluminium, Arsenic, Cadmium, Chromium, Copper, Mercury, Nickel, Lead, Zinc, Cyanide Phenol, and Total Hydrocarbons.
Breaches of the consent were recorded as follows:
• One smell complaint was received. This complaint was investigated but could not be substantiated.
• Six discharge transgressions for Ecoli/Faecal Coliforms. Three of these transgressions were associated with an issue with a high sludge blanket in the clarifier, which spilled through to the UV. The sludge blanket incident resulted in a West Coast Regional Council written warning. All of the breaches were reported at the time to the West Coast Regional Council.
No complaints regarding
objectionable odour from the treatment plants
Zero One unsubstantiated smell complaint received (2010: no complaints received)