Biofilm Biofilter media replacement in Canterbury

Biofiltration System and Bark Biofilter Maintenance

Recently, many South Island councils, including Nelson City Council, have conducted testing of their biofiltration systems, used to reduce odours from sites such as sewage treatment plants. These tests have shown a wide range of performance by biofilters, with the primary cause of poor performance being a lack of regular maintenance.

 

Under the Resource Management Act, the primary responsibility for managing air quality lies with regional councils and unitary authorities. They must mitigate any adverse effects of activities on the environment, including the production of offensive odours. Many councils use biofiltration to reduce odours, such as hydrogen sulphide, that are emitted from sewage treatment.

 

Biofiltration is where organic contaminants in a gas stream pass through a bed of material and adsorb to the surface, where they are broken down by the micro-organisms present. Volatile compounds break down to carbon dioxide, water, mineral salts, and other harmless products. The bed material may be shell, bark, compost or any mixture of these components.

 

Unfortunately, biofiltration systems are not always operated at suitable conditions to achieve the desired odour control. If biofilters are overloaded, sorption sites are filled faster than they are regenerated by bio-oxidation, resulting in odorous compounds passing through the biofilter into the atmosphere.

 

Selection of the appropriate biofiltration medium is critical. The medium should have a large active particle surface area to absorb gases, attach microorganisms, and effect good water holding. It must be sufficiently porous to maintain alow pressure drop and provide good drainage. It should have chemical characteristics that help to support and sustain the growth of micro-organisms.

 

The moisture content, drainage, pH, temperature, nutrient availability of the medium and the pressure drop across the medium must be monitored and controlled within suitable limits to maximise biofilter performance.

 

Depending upon the medium used, the recommended optimal moisture content normally ranges between 20% and 60% on a weight basis. Options for moisture control include humidification of the biofilter influent gas and irrigation of the biofilter surface.

 

Biofiltration medium pH is recommended to be in the range of 6 to 8 and should be checked regularly and measured at several depths. Crushed limestone or shell can be added to raise a low pH and extend the life of the biofilter.

 

Temperature affects not only microbial activity but also the solubility of odorous compounds in water and the sorption capacity of the biofilter medium. Studies have shown that an operating temperature between 20 and 40°C provides optimum results. As temperature affects not only the activity but also the composition of microbial populations, sharp temperature fluctuations in the biofilter should be avoided.

 

 

Bells Island waste water treatment plant renewal project
Pictured: A refreshed and serviced biofilter located in the Tasman region.

 

The microorganisms in biofilters require nutrients for growth. It is generally thought that most biofilter media and influent gases contain enough nutrients so that none need to be added. However some biofilters designed to operate at high loading rates and over long periods of time, may require the addition of nitrogen.

 

Another key factor in the design and maintenance of biofiltration systems is the pressure drop across the biofilter medium, which is a function of the gas loading rate and is influenced by the type, depth and moisture content of the biofilter medium. Monitoring will detect compaction and indicate when loosening or replacement of the medium is required.

 

When properly designed, operated and maintained, biofilters have proved to be an effective odour control technology. The biofilter medium chosen must be able to support and sustain a diverse microbial population.

 

BioFilm, manufactured by Wholesale Landscapes for more than 10 years, is a specialist, branded technical media used in biofiltration systems all over the South Island by local government and private organisations. When working efficiently, BioFilm removes more than 90% of air pollutants, including those that some agencies class as hazardous, such as hydrogen sulphide. BioFilm is a contaminant-free, all-natural product, manufactured from recycled, carbon-neutral materials.

 

Wholesale Landscapes can provide expert consultants to advise on your specific project. Common services undertaken by Wholesale Landscapes include testing of current conditions, reporting findings and creating recipes and products suitable for your site.

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Our Retailers

This product isn’t distributed directly by Wholesale Landscapes. We can only guarantee stock at our Lifestyles Yard located at 55, Saxton Road, Stoke, Nelson. 

If this doesn’t suit you or you require a smaller volume under 1.5m3, please see the list of retailers for the same or similar alternative products.

Nelson
  • Wholesale Landscapes – Stoke Lifestyles Yard

  • Stoke Garden & Landscapes

Richmond
  • Bay Landscape & Garden Centre

  • Goldpine Richmond

Mapua
  • Mapua Landscapes

Motueka
  • Stonescape Landscape Supplies (Concrete & Metals)

North Canterbury
  • Woodend Landscape Supplies

Christchurch
  • Garden Box – Middleton

  • Urban Paving – Harewood

  • Pearsons Landscape Supplies – Bromley

  • Styx Mill Landscape & Nursery  – Styx               

  • Mitre 10 Ferrymead 

South Canterbury
  • Fulton Hogan Timaru

  • Ashburton Construction Ltd (ACL)

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Our Retailers

We’re working on providing you with all the information you need in just a couple of clicks.  Below is a list of our major retailers. Please contact them for stock and supply.

 

PLEASE NOTE: Not all of our products are supplied to all retailers. We can only guarantee product quality of products we manufacture.

Nelson
  • Wholesale Landscapes – Stoke Lifestyles Yard

  • Stoke Garden & Landscapes

Richmond
  • Bay Landscape & Garden Centre

  • Goldpine Richmond

Mapua
  • Mapua Landscapes

Motueka
  • Stonescape Landscape Supplies (Concrete & Metals)

North Canterbury
  • Woodend Landscape Supplies

Christchurch
  • Garden Box – Middleton

  • Urban Paving – Harewood

  • Pearsons Landscape Supplies – Bromley

  • Styx Mill Landscape & Nursery  – Styx               

  • Mitre 10 Ferrymead 

South Canterbury
  • Fulton Hogan Timaru

  • Ashburton Construction Ltd (ACL)

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Organise Your Pick-Up

We welcome pick-up of product by the public for volumes 1m3 and over. If your trailer is unable to hold the weight of our minimum pick up volume, please book a delivery. Please check your estimated trailer weight rating below.

single-axle-trailer-landscape-supplies-bulk
Standard trailer
(750kg limit)
  • Bark / Mulches
  • Shell
  • Compost
  • Soil
  • Stones / Aggregates
tandem-trailer-landscape-supplies-bulk
Tandem trailer
(1,500kg limit)
  • Bark / Mulches
  • Shell
  • Compost
  • Soil
  • Stones / Aggregates
tip-truck-landscape-supplies-bulk
Tip truck
(2,000kg limit)
  • Bark / Mulches
  • Shell
  • Compost
  • Soil
  • Stones / Aggregates

Product Volume Calculator

Product Volume Required: 0.1 m3


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*we will quote to the nearest cubic meter

Recommended depths

Typically you need a finishing layer of screened soil of 100mm when working with an uneven surface. 100mm of soil will allow to even out any hollows and give enough depth to create a flat surface

A general rule for compost is to allow for the depth of the current root structure of your plants with an additional 30-50% to mix in with the base. If you’re planting into holes or filling up a vege garden  you will need to accommodate for this prior to filling up

We recommend 100mm (10cm) deep for new bark gardens and planting into bare areas. For existing gardens with some cover, we recommend 75mm-100mm (7.5cm-10cm)

Note: Barked areas for playground impact protection need to meet NZS5828:2015 standards and is calculated on the fall areas and the height of the playground. Please contact us to discuss your barked playground areas

For paths and driveways which are often exposed to car and foot traffic, we recommend 100mm-125mm (10cm-12.5cm) on newly prepared areas due to settling of product.

This excludes preparation, compaction or drainage gravel underneath. For existing areas 75mm thickness is recommended for areas needing a small top-up. 

Our Truck Volumes

3T Truck

Full truckload volumes
  • 6m3 Bark
  • 1.5m3 Stone
  • 3m3 Soil
  • 3m3 Supersoil
  • 4m3 Compost
  • 3m3 Shell

7.5T Truck

Full truckload volumes
  • 15m3 Bark
  • 4m3 Stone
  • 8m3 Soil
  • 8m3 Supersoil
  • 10m3 Compost
  • 8m3 Shell

11T Truck

Full truckload volumes
  • 25m3 Bark
  • 7m3 Stone
  • 10m3 Soil
  • 11m3 Supersoil
  • 15m3 Compost
  • 11m3 Shell
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