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K4 Results: 21–27 February 2008

K4.1 General waste

K4.1.1 Primary composition of general waste

The primary composition of the general waste is presented in Table K4.1 and Figure K4.1. The secondary composition, which includes all 22 categories, is given in Appendix K10.

Table K4.1: Primary composition of general waste, 21–27 February 2008

Primary category % of total
(±95% confidence level)
Tonnes/week
Paper 10.9 (±1.7) 2.2
Plastics 12.0 (±2.1) 2.5
Putrescibles 31.9 (±8.0) 6.5
Ferrous metals 5.3 (±1.3) 1.1
Non-ferrous metals 1.1 (±0.4) 0.2
Glass 6.6 (±1.5) 1.3
Textiles 5.6 (±1.3) 1.2
Nappies and sanitary 8.5 (±1.6) 1.7
Rubble 4.8 (±3.5) 1.0
Timber 10.9 (±6.0) 2.2
Rubber 1.0 (±0.6) 0.2
Potentially hazardous 1.3 (±0.3) 0.3
Total 100   20.5

Figure K4.1: Primary composition of general waste, 21–27 February 2008

Putrescible material was the largest single component of the general waste, comprising 32 per cent of the total. Half of the putrescible material was food waste from both households and businesses. Plastics was the second largest component, with 12 per cent of the total.

K4.1.2 General waste, by activity source

The general waste being disposed of at Kaikoura Landfill comprises all waste other than kerbside collections and loads of glass collected by Innovative Waste Kaikoura and disposed of to landfill. During the survey period data was gathered on 299 loads of general waste. This included waste from C&D, ICI, landscaping and earthworks, and residential activity. As each load of general waste was disposed of, it was assessed as to which of these activities had resulted in its generation.

From the weighbridge records for the survey week, it was estimated that 20.5 tonnes of general waste were disposed of at the facility. Determining the actual weight to landfill was problematic, because some vehicles disposed of recoverable materials at the separate drop-off points after the vehicle had been weighed and before disposing of the residual waste at the tipping floor. In these instances the surveyor’s estimate of the load weight was used and the weighbridge records adjusted accordingly. A further complication was that some vehicles classified as ‘green waste’ at the weighbridge also disposed of residual waste at the tipping floor. Vehicles classified at the weighbridge as ‘green waste’ were not included in the total for general waste.

Table K4.2 shows the percentage of loads originating from each activity, the percentage of total weight, and the tonnes per week.

Table K4.2: Activity source of general waste, 21–27 February 2008

Activity source No. of loads surveyed % of loads % of total weight Tonnes/week
Construction and demolition 5 1.7 6.4 1.3
Industrial/commercial/institutional 107 35.8 57.0 11.7
Landscaping and earthworks 15 5.0 11.4 2.3
Residential 172 57.5 25.2 5.2
Total 299 100 100 20.5

Residential activity was the source of 58 per cent of all loads of waste, but these loads accounted for only one-quarter of the total weight of general waste. This is due to a large number of residential waste loads being relatively small, such as when bags of domestic refuse are dropped off. Just over a third of all loads were generated by ICI activity, and these loads accounted for 57 per cent of the total weight. C&D loads, while representing less than 2 per cent of all general waste loads, accounted for over 6 per cent of the total weight. Waste from landscaping activity generated 5 per cent of loads and 11 per cent of the total weight.

K4.1.3 Primary composition of general waste, by activity source

The primary composition of the four activity sources of general waste is shown in Table K4.3. The secondary composition is given in Appendix K11.

Table K4.3: Primary composition of general waste, by activity source, 21–27 February 2008

Primary category C&D
%
ICI
%
Landscaping
%
Residential
%
Paper 0.6 13.6 0.0 12.2
Plastics 1.0 14.2 2.8 14.1
Putrescibles 0.7 28.4 85.4 23.5
Ferrous metals 0.8 5.5 2.9 7.0
Non-ferrous metals 0.4 1.1 0.0 1.7
Glass 0.2 9.2 0.0 5.2
Textiles 3.4 5.1 0.0 9.9
Nappies and sanitary 0.1 11.0 0.0 9.0
Rubble 37.8 1.8 4.6 3.6
Timber 53.7 7.1 4.2 11.6
Rubber 1.0 1.3 0.0 1.0
Potentially hazardous 0.4 1.7 0.1 1.2

Timber and rubble together comprised most of the C&D waste (91 per cent). ICI waste was more heterogeneous, with no single material comprising more than 29 per cent of the total. Food waste was the largest single component of ICI waste, reflecting the relative size of the hospitality industry in the region. Landscaping waste was primarily green waste (85 per cent), with rubble (mainly soil) and timber each comprising about 4 per cent. The largest component of residential waste was putrescible material (24 per cent), which included both food waste from domestic bag drop-offs and landscaping waste. Many residential loads carry waste from several activities, so small quantities of landscaping and C&D waste may be present in a load that was classified as being generated by residential activity.

K4.1.4 General waste, by vehicle type

For each vehicle load of waste disposed of on the tipping floor, the vehicle type was recorded. Table K4.4 shows the percentage of loads transported by each of the vehicle types, the percentage of total weight carried by each vehicle type, and the tonnes per week.

Table K4.4: General waste, by vehicle type, 21–27 February 2008

Vehicle type No. of loads % of loads % of weight Tonnes/week
Cars 134 45 12 2.4
Compactors 0 0 0 0.0
Front-loader trucks 0 0 0 0.0
Gantry trucks 0 0 0 0.0
Huka trucks 0 0 0 0.0
Other trucks 41 14 29 5.9
Trailers 124 41 59 12.2
Total 299 100 100 20.5

No compactors, front-loader trucks, gantry trucks or huka trucks disposed of general waste during the survey period. Almost half of the loads disposed of on the tipping floor were carried by cars, but car loads accounted for only 12 per cent of the total weight. Many of these car loads comprised a small number of domestic rubbish bags. Trailers represented 41 per cent of all vehicle loads, but these loads accounted for 59 per cent of the total weight.

K4.1.5 Primary composition of general waste, by vehicle type

The primary composition of loads carried by the three main types of vehicles that disposed of waste is shown in Table K4.5. The secondary composition is shown in Appendix K12.

Table K4.5: Primary composition of general waste, by vehicle type, 21–27 February 2008

Primary category Car
%
Other truck
%
Trailer
%
Paper 14.0 12.9 9.2
Plastics 14.5 13.8 10.7
Putrescibles 34.2 28.4 33.2
Ferrous metals 4.8 5.7 5.2
Non-ferrous metals 1.0 1.0 1.1
Glass 4.9 10.3 5.1
Textiles 6.0 5.0 5.8
Nappies and sanitary 11.8 10.5 7.0
Rubble 2.1 2.3 6.6
Timber 4.7 6.6 14.2
Rubber 0.8 1.7 0.8
Potentially hazardous 1.3 1.6 1.2

K4.2 Overall waste to landfill

K4.2.1 Source of overall waste to landfill

The overall waste stream being disposed of at Kaikoura Landfill comprised the general waste stream, the private kerbside collection, and glass disposed of by Innovative Waste Kaikoura for landfill stabilisation (special waste). The composition of the overall waste stream has been determined by combining information from the weighbridge records for the survey week with the results of the visual survey.

From the survey it was determined that kerbside refuse collections were being disposed of by a single private waste operator. Weighbridge records were used to calculate the weekly tonnage from this operator. The weekly tonnage of general waste was also calculated from the weighbridge records. Because many small vehicle loads were not weighed by the weighbridge, it was necessary to assign average load weight figures for those vehicles. The amount of glass disposed of to landfill was based on the surveyor’s records because most of the glass entering the facility was stockpiled.

Table K4.6: Waste types to landfill, 21–27 February 2008

Waste type % of weight Tonnes/week
General 76 20.5
Kerbside collections 15 4.2
Special 9 2.4
Transfer station 0 0
Total 100 27.1

A total of 27 tonnes of refuse was disposed of during the survey period. This figure does not include loads of green waste, glass or steel that were disposed of at the separate drop-off points. Of the 27 tonnes disposed of during the week, over three-quarters was general waste. The general waste included the drop-off of domestic refuse by many residents.

K4.2.2 Primary composition of overall waste to landfill

The primary composition of the overall waste to landfill is calculated by combining the compositions of the three different waste types in the proportions shown in the previous section. The compositions of the three different waste types have been determined as follows:

  • general waste – as determined from survey results and shown in Section K4.1.1

  • kerbside collection – assumed to be the composition given in Appendix K1, which is based on the results of the previous audits of domestic kerbside refuse undertaken by Waste Not Consulting

  • special – the special waste is all recyclable glass.

The primary composition of the overall waste stream is given in Table K4.7 and Figure K4.2. The secondary composition is given in Appendix K13.

Table K4.7: Primary composition of overall waste, 21–27 February 2008

Primary category % of total Tonnes/week
Paper 10.4 2.8
Plastics 11.3 3.1
Putrescibles 31.5 8.5
Ferrous metals 4.4 1.2
Non-ferrous metals 0.9 0.2
Glass 14.9 4.0
Textiles 4.6 1.2
Nappies and sanitary 7.8 2.1
Rubble 4.0 1.1
Timber 8.3 2.3
Rubber 0.8 0.2
Potentially hazardous 1.1 0.3
Total 100 27.1

Figure K4.2: Primary composition of overall waste, 21–27 February 2008

Putrescible material comprised the largest primary classification of the overall waste stream, with over 30 per cent of the total. Over half of the putrescible material was kitchen/food waste in kerbside refuse and ICI refuse. Much of the green waste was disposed of to landfill because it was unsuitable for the composting process. Glass was the second largest category, with 15 per cent of the total.

K4.3 Discussion and analysis

K4.3.1 C&D waste

Loads of waste generated by C&D activity (see Section 2.6 for the taxonomy of C&D waste) were identified during the visual survey of the general waste stream. Kerbside refuse, the other waste stream besides general waste disposed of at the facility, contains negligible quantities of C&D waste. Special waste contains no C&D waste. The quantity of C&D waste in the overall waste stream is calculated in Table K4.8.

Table K4.8: C&D waste, 21–27 February 2008

Total C&D waste in general waste 1.3 tonnes (from Table K4.2)
Overall waste to landfill 27.1 tonnes (from Table K4.6)
C&D waste as proportion of overall waste to landfill 4.8%

Table K4.8 shows that C&D waste comprised 4.8 per cent, by weight, of the overall waste to landfill.

K4.3.2 Factors affecting waste generation and disposal during survey period

A range of factors affect the quantity and composition of waste disposed of at any individual disposal facility. Some of the factors thought to be relevant to the waste disposed of during the 21–27 February 2008 survey period are discussed below.

K4.3.2.1 Weather before and during the survey period

The February audit took place during a very dry summer. The NIWA National Climate Summary for January 20083 states: “January 2008 rainfall was less than 25 percent (quarter) of normal in ... coastal Marlborough and north Canterbury”. This could have affected waste generation related to gardening and agricultural activity, given that vegetative growth would have been slowed by the conditions.

K4.3.2.2 Tourism and construction activity

Tourism is a major contributor to the Kaikoura economy, and the tourism sector is likely to be a major waste generator. February is the peak of the season so it was expected that waste volumes in February would be greater than in the September and November audits. Construction activity is generally higher in summer than in winter, but the February audit showed less C&D waste than the previous audits in September and November. Construction in Kaikoura might be scheduled to occur during the winter months to avoid disruption during the tourist season. The sample size, however, is very small, with five C&D loads being included in the February audit compared to 11 loads in the November audit, so the results should be considered to be indicative only.

K4.3.2.3 Individual waste generators

The quantity of waste disposed of at Kaikoura Landfill is sufficiently small for the composition to be changed significantly by the waste disposal behaviour of a single waste generator. The size of the residual waste stream at Kaikoura Landfill means that the composition may vary considerably from week to week, unlike at larger facilities.