(a) Christchurch City Council
The Christchurch City Council has undertaken one kerbside kitchen waste collection trial and is in the process of beginning another.
Kitchen organics collection trial (May-July 2002) [See Christchurch City Council, http://www.ccc.govt.nz/Waste/Composting/KitchenOrganicsTrial.asp (accessed 14 February 2005).]
The first kitchen organics collection trial was undertaken in 2002. It involved 475 households in two suburbs – one affluent suburb and the other less affluent. Each household was provided with a four-litre bucket with a twist top for their kitchen and a 20-litre kerbside bucket with a suction seal lid. The four-litre bucket had labels attached that indicated to participants what materials could and could not be diverted.
Half of the households were given biodegradable corn-starch bags with which to line their kitchen buckets. The remaining participants were provided with bags of EM Bokashi [EM Bokashi is a commercially available dry granular product containing beneficial micro-organisms that can help to reduce odour.] and instructions on how to use it to control odour.
The kitchen waste was collected weekly in a sealed (watertight) refuse collection truck. The 20-litre kerbside buckets were simply tipped into the back of the truck and banged to knock out any material sticking to the inside of the bucket.
Participation was very high, with nearly all households using the service on a regular basis. The organic waste collected was "relatively dry and free of contaminants". The Christchurch City Council surveyed the trial participants and found that "those involved were overwhelmingly supportive and were not only willing to continue to use it ... but were also willing to pay for the service in the rates".
There was no difference in participation rates between the two suburbs taking part in the trial. This indicated that socioeconomic factors may not influence participation in a household organics kerbside collection scheme.
Key recommendations from the trial were as follows.
- Lining the buckets would be crucial for the collection service to be acceptable to the public.
- The kitchen bucket needs a detachable flip-top lid for ease of use.
- The kerbside container should also have a flip-top lid.
- Provision of kerbside organics collections for businesses should be considered.
- Support should be given to maximising commercial green-waste collection services instead of instigating mixed organic refuse collections.
- Supermarkets and retail outlets should be encouraged to move towards biodegradable carry bags to feed into an organics collection system.
According to research undertaken by Polargruppen, use of the company's biodegradable, corn-starch "BioBag" has the following benefits when used in combination with aerated bins: [See Polargruppen at http://www.polargruppen.com/biobag.htm (accessed 14 March 2005).]
- 100% biodegradability and compostability
- completely biodegraded after 10 to 45 days depending on the composting method
- moisture reduction of up to 25% by weight in five days
- odour minimisation
- bags can be pigmented with biodegradable material
- bags can have information printed on them.
Kitchen organics collection trial (February-December 2005)
The current Christchurch City Council trial builds on the 2002 trial. The eight-litre kitchen "BioBin" has a flip-top lid and the kerbside container is now a 48-litre or 80-litre flip-top MGB. Collection is again on a weekly basis, involves two suburbs and 500 households, and is for kitchen waste and green waste.
The kitchen bin is not lined and participants are required to empty and wash the bin on a regular basis. Participants are also asked to:
- line the MGB with dry twigs or leaves to reduce material sticking to the inside
- wrap their food scraps from the kitchen bin in newspaper prior to placing in the MGB
- rinse the MGB on a regular basis to avoid odour.
The trial will:
- assess the overall level of participation over time, including those who compost at home, those who use insinkerators and those who do not separate organics from their general household rubbish
- assess public acceptance, opinion and feedback on the organics collection service
- assess the amount of organics collected per household for each bin size over the four seasons, which will enable the Council to assess composting plant options
- test the "cheapest and worst-case" collection option for wrapping food scraps in paper and then compare this with a biodegradable bag liner. Some households will be given Bio-Bags midway through the trial to compare with the paper option. The additional cost and level of service (benefit) can then be assessed. [Personal communication, Tony Moore (Senior Planner - Solid Waste, Christchurch City Council), 15 February 2005.]
The organics collected from this trial are being composted in outdoor windrows. A fully enclosed composting system would be used if the Council decided to introduce the service citywide.
(b) Mackenzie District Council [Personal communication, John McGartland (Solid Waste Manager, Mackenzie District Council), 31 January 2005. See also Mackenzie District Council http://www.mackenzie.govt.nz/solidwaste/.]
Mackenzie District Council implemented an organic waste kerbside collection scheme in May 2002 in response to landfill closures in the area and the high cost of waste transport to alternative destinations. Residential waste from 1500 households in Twizel, Fairlie and Tekapo is placed in colour-coded, pre-paid bags for kerbside collection. Organics go into a green bag, commingled recyclables into a clear bag and residual waste in a black bag. Residents may include "light" green waste in the organics bag.
The prices for the bags are:
- black rubbish bags $1.00 each
- green bags for compostables $0.50 each
- clear bags for recyclables $0.25 each.
The organics bags are not biodegradable and need to be split open manually to feed the contents into the district's vertical composting unit. This method was assessed as the best practicable option for the district at the time. The Council is investigating the use of 300-litre bins that could contain all of the three types of bags by having them hang on hooks inside the bin. This move is to make household waste management less cumbersome for residents.
The experience of the Council is that animal strike is not an issue so long as residents put their bags out the night before or on the morning of collection. The introduction of bins will further reduce the potential for animal strikes.
Restaurants in the area are also collecting kitchen waste using 20-litre buckets. These buckets are delivered to the transfer station by the restaurant workers or by a private contractor.
Mackenzie District Council reported that there was some initial resistance to the scheme, but persistent education over 12 months has resulted in 75–80% diversion of organics. The level of contamination in the organic waste is around 5%.
There are a substantial number of holiday homes in the Mackenzie District, and communication with these part-time residents regarding collection services can be difficult. Mackenzie District Council initially provided these residents with a booklet outlining the Council's waste services and residents' own waste management responsibilities but found it to be ineffective. The Council is considering the distribution of a fridge magnet to cover these matters and anticipates that this will be a successful way of communicating with holiday home owners.
(c) Ministry for the Environment
The Ministry for the Environment trialled small-scale food-waste separation from two floors at its head office for a year. A staff member took the food waste to a home-composting system. This pilot trial was expanded to a full-scale operation covering all 13 floors in 2003 under the Govt 3 programme. [Ministry for the Environment, http://www.mfe.govt.nz/issues/sustainable-industry/govt3/about-govt3.html (accessed 21 February 2005).] Organics are collected in an open paper bag placed in an aerated bin, a method founded on the Smedlund "open system" of managing organic waste.
The Ministry's regional offices have source-diverted food wastes since 2001 via buckets to home compost systems. EM Bokashi is used in Christchurch and ordinary sealed buckets are used in Auckland.
The Smedlund system is based around the use of paper bags and the larger paper sacks to provide maximum air flow (ventilation) around the organic waste. The benefits of this approach, according to research undertaken by Smedlund, are: [Smedlund Miljosystem, 1995. See also Smedlund, http://www.smedlund.se (accessed 21 February 2005).]
- less odour due to greater exposure to air (oxygen)
- reduced collection frequencies due to reduced susceptibility of waste to odour
- greater weight reduction of organic waste due to greater evaporation
- paper bags can be fed into any waste treatment facility
- no need to rinse bins.
At the Ministry's head office the bags are collected nightly by the cleaners, folded, closed and placed in a 240-litre MGB for weekly transfer to an in-vessel composting plant. The paper bags compost down in the process with no visible residues. There have been no observed contaminants from staff. Contamination found when the cleaners were learning the new system was removed by the collector.
For household kerbside organic waste collections, Smedlund offer a special holder for the paper bag for use in the kitchen. This bag is then placed in a large paper sack for kerbside collection along with green waste, if need be. The sack can be held in a wire trolley, shaped like an MGB, with a flip-top lid. This design allows ventilation of the sack before collection.
(d) North Shore City Council [North Shore City Council, 2003.]
An eight-week organic waste collection trial was undertaken by the North Shore City Council in mid-2003 as part of a wider trial looking at the viability of various recycling options for the city. The purpose of the organic waste collection trial was to evaluate the effectiveness of collecting kitchen waste by itself and in combination with garden waste.
All participants in the trial were provided with a seven-litre kitchen bin (unlined) and either a 45-litre MGB for kitchen scraps only or a 120-litre MGB for combined kitchen waste and green waste.
Four hundred households took part in the trial, which had a participation rate of 71%. The average contamination rate of the organic waste was very low at 0.9%. Most residents (68%) were supportive of having a permanent organic waste-collection service for combined kitchen and green wastes.
(e) Timaru District Council [Personal communication, Brian Gallagher (Solid Waste Manager, Timaru District Council), 16 February 2005; see also: Council moving to kerbside recycling soon, Timaru Herald 9 February 2005: 1.]
Timaru District Council ran a three-bin kerbside recycling trial for 100 households in December 2004 and January 2005. Commingled recyclables and organic waste (kitchen and garden waste) were collected in two 240-litre bins, and a 120-litre bin was used for residual household waste. The 240-litre bins were emptied weekly, with a fortnightly collection for the 120-litre bins.
Final results from the trial were unavailable at the time this report was written, but over 85% of participants supported the trial and 48% gave strong approval. Significantly, 75% of participants were happy to pay an additional $1.35 per week for the service.
Due to the success of this trial the Timaru District Council are tendering for a collection system, a processing option and market development for the recycled products. The three-bin system is the preferred option at this stage, although the tender process may bring to light an alternative. It is anticipated that the chosen recycling system will be operative by July 2006.