Cleaning and product performance report on The Ecosol RSF 100 At-Source Solid Pollutant Filters for Tauranga City Council Prepared by Ecosol (NZ) Wastewater Filtration Systems Ltd Nicholas Watson June 2005
Tauranga is a seaside city located in the Bay of Plenty region on the east coast of New Zealand.
Tauranga City Council (TCC) is one of the smallest districts in terms of land area, with only 12,742 hectares. However, Tauranga City has a population of over 100,000 people, making it the sixth most densely populated city in New Zealand. This figure is set to increase over the next 5 years as demonstrated by the 2001 census, which showed a 19.3% growth in the number of new dwellings in Tauranga.
The area is known for its beautiful weather, having about 2,200 hours of sunshine per year. The average rainfall for the city is 1,349mm and the average temperature is 14.2 degrees. The city swells with holidaymakers in summertime, many make the 206km journey from Auckland every year to enjoy the aquatic lifestyle, beaches, and many marinas.
With this activity comes added strain on services, one being Tauranga’s stormwater drainage network. TCC currently manages approximately 6,000 cesspits and is required by the Regional Council to lower discharges from the CBD area into the harbour. One of TCC’s initiatives is the installation of stormwater filters at selected locations to reduce the level of pollutants entering the drainage network.
In June 2002 TCC engaged Ecosol (NZ) to install three RSF 100 units as part of a trial. After two years of monitoring, TCC decided to install further units as part of ongoing redevelopment works. Ecosol, after the success of the trial, won the tender to install a further 22 units baskets in the CBD area and also at a major suburban intersection. These units were installed in December 2004.
All of the RSF 100 units were fitted with 200 micron mesh.
This report summarises the results of the first clean of all 25 installed units.
Ecosol, in conjunction with TCC, randomly selected four of the 25 RSF 100 units to be independently tested by SGS Food Environment Laboratories. The units selected for testing were:
||CNR Cameron Road and State Highway 2
||Elizabeth Street CBD
||Spring Street Mall CBD
||Cnr The Strand and Commercial Road CBD
As Ecosol’s RSF 100 units can be cleaned either manually or by eductor truck, the four test units were cleaned manually while the remainder was cleaned using an eductor truck supplied by Tankman Waste Disposal Services, for City Care, TCC’s maintenance contractors. The total time taken for the clean, including travelling time and disposal, four hours.
Tankman’s group operation manager, with assistance from Ecosol’s representative, conducted the sampling. The samples taken consisted of the complete contents of each basket, which was then weighed using City Care’s electronic scales. The four samples were then transported to SGS Food and Environment Laboratories in Penrose, Auckland and tested for pollutant content, including heavy metals and hydrocarbons. SGS also carried out a sieve analysis to determine the capture efficiency of the RSF 100 mesh.