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M3 Results: 20–26 November 2007

M3.1 General waste

M3.1.1 Primary composition of general waste

The primary composition of the general waste is presented in Table M3.1 and Figure M3.1. The secondary composition, which includes all 22 categories, is given in Appendix M6.

Table M3.1: Primary composition of general waste, 20–26 November 2007

Primary category % of total
(± 95% confidence level)
Tonnes/week
Paper 6.2% (±1.8%) 2.8
Plastics 9.5% (±4.3%) 4.3
Putrescibles 5.5% (±2.5%) 2.5
Ferrous metals 10.1% (±4.3%) 4.6
Non-ferrous metals 0.7% (±0.3%) 0.3
Glass 3.7% (±1.7%) 1.6
Textiles 5.4% (±2.9%) 2.4
Nappies and sanitary 0.7% (±0.1%) 0.3
Rubble 29.0% (±18.3%) 13.1
Timber 28.4% (±10.8%) 12.8
Rubber 0.4% (±0.3%) 0.2
Potentially hazardous 0.4% (±0.3%) 0.2
Total 100%   45.1

Figure M3.1: Primary composition of general waste, 20–26 November 2007

Timber and rubble were the largest components of the general waste, at 28 per cent and 29 per cent, respectively. Timber and rubble are the major components of C&D waste, which was the largest activity source of general waste. Plastics and ferrous metals were the third and fourth largest components, with both comprising about 10 per cent of the total.

M3.1.2 General waste, by activity source

For the purpose of this report, general waste represents the waste discharged at the Matamata Transfer Station that has not come from kerbside collections. Using the activity source categories (as listed in Section 2.4), general waste therefore comprises waste from C&D, ICI, landscaping and earthworks, and residential activities. During the survey period data was gathered on 181 loads of general waste. 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 45.1 tonnes of general waste were disposed of at the facility. Table M3.2 shows the percentage of loads originating from each activity, the percentage of total weight, and the tonnes per week.

Table M3.2: Activity source of general waste, 20–26 November 2007

Activity source No. of loads surveyed % of loads % of total weight Tonnes/week
Construction and demolition 28 13% 66% 29.9
Industrial/commercial/institutional 20 10% 10% 4.6
Landscaping and earthworks 6 3% 2% 0.9
Residential 154 74% 22% 9.7
Total 208 100% 100% 45.1

Residential activity was the source of nearly three-quarters of all loads of waste, but these loads only accounted for less than 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. C&D loads, while representing only 13 per cent of all general waste loads, accounted for two-thirds of the total weight. Waste from landscaping activity generated 3 per cent of loads and 2 per cent of the total weight.

M3.1.3 Primary composition of general waste, by activity source

The primary composition of the four activity sources of general waste are shown in Table M3.3. The secondary composition is given in Appendix M7.

Table M3.3: Primary composition of general waste, by activity source, 20–26 November 2007

Primary category C&D ICI Landscaping Residential
Paper 3.9% 14.8% 3.3% 9.3%
Plastics 4.6% 34.3% 2.7% 13.6%
Putrescibles 3.4% 6.0% 21.3% 10.2%
Ferrous metals 10.1% 4.4% 0.3% 13.7%
Non-ferrous metals 0.6% 0.9% 0.0% 0.8%
Glass 3.1% 6.9% 2.6% 3.8%
Textiles 5.0% 3.1% 0.3% 8.3%
Nappies and sanitary 0.0% 0.9% 0.6% 2.7%
Rubble 39.4% 3.0% 67.6% 5.7%
Timber 29.2% 25.0% 1.3% 30.1%
Rubber 0.3% 0.5% 0.0% 0.9%
Potentially hazardous 0.3% 0.3% 0.0% 1.0%

C&D waste was primarily composed (69 per cent) of timber and rubble. The largest component of ICI waste was plastics (34 per cent), but over half of the plastic was contained in a single load of waste from an explosives manufacturer in Tauranga. Landscaping waste was primarily rubble (mainly soil), at 68 per cent, with green waste comprising about 20 per cent. The largest component of residential waste was timber, which comprised 30 per cent of the total. Over half of the timber arrived in two loads of waste.

M3.1.4 General waste, by vehicle type

For each vehicle load of waste disposed of on the tipping floor, the vehicle type was recorded. Table M3.4 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 M3.4: General waste, by vehicle type, 20–26 November 2007

Vehicle type No. of loads % of loads % of weight Tonnes/week
Cars 122 59% 9% 4.0
Compactors 0 0% 0% 0.0
Front-loader trucks 0 0% 0% 0.0
Gantry trucks 15 7% 57% 25.8
Huka trucks 0 0% 0% 0.0
Other trucks 12 6% 7% 3.1
Trailers 59 28% 27% 12.2
Total 208 100% 100% 45.1

No front-loader trucks or huka trucks disposed of waste during the survey period. All compactor trucks using the facility were transporting kerbside collections, which are not classified as general waste. Nearly 60 per cent of the loads disposed of at the transfer shed were carried by cars, but car loads accounted for only 9 per cent of the total weight. Many of these car loads comprised a small number of domestic rubbish bags. Although gantry trucks accounted for only 7 per cent of vehicle loads, these loads represented 57 per cent of the total weight. Most of the gantry loads were C&D waste. Trailers represented 28 per cent of all vehicle loads and accounted for 27 per cent of the total weight.

M3.2 Primary composition of general waste, by vehicle type

The primary composition of loads carried by the four main types of vehicles that disposed of waste are shown in Table M3.5. The secondary composition is shown in Appendix M8.

Table M3.5: Primary composition of general waste, by vehicle type, 20–26 November 2007

Primary category Car Gantry truck Other truck Trailer
Paper 15.0% 3.7% 5.2% 8.8%
Plastics 16.5% 4.6% 34.7% 11.3%
Putrescibles 20.2% 3.6% 1.9% 5.5%
Ferrous metals 7.1% 11.1% 8.6% 9.4%
Non-ferrous metals 1.4% 0.5% 0.3% 0.9%
Glass 6.6% 2.4% 5.2% 4.9%
Textiles 8.5% 5.8% 6.9% 3.3%
Nappies and sanitary 5.9% 0.0% 0.1% 0.6%
Rubble 7.6% 36.5% 8.5% 25.4%
Timber 10.6% 31.3% 28.1% 28.3%
Rubber 0.2% 0.4% 0.3% 0.7%
Potentially hazardous 0.4% 0.3% 0.3% 0.8%

M3.2 Overall residual waste

M3.2.1 Source of overall residual waste

Because there was no special waste, or waste from other transfer stations, being disposed of at Matamata Transfer Station, the overall residual waste stream comprised only the general waste stream and kerbside collections. The composition of the overall residual waste stream has been determined by combining information from the weighbridge records for the survey week with the results of the visual survey.

The survey found that kerbside collections were transported to the Matamata Transfer Station by two private waste operators as well as the council contractor. Using the weighbridge records, the tonnages of kerbside collection waste and general waste were calculated, and these are shown in Table M3.6. Because small vehicle loads such as trailers and cars were recorded by the weighbridge but not weighed, it was necessary to use average load weight figures for these vehicles.

Table M3.6: Overall residual waste types, 20–26 November 2007

Waste type % of weight Tonnes/week
General 46.8% 45.1
Kerbside collections 53.2% 51.3
Special 0% 0
Transfer station 0% 0
Total 100% 96.3

A total of 96 tonnes of refuse were disposed of during the survey period. This figure does not include loads of green waste or steel that were disposed of at the separate drop-off points. Of the 96 tonnes disposed of during the week, slightly over half was from kerbside collections and slightly under half was general waste.

M3.2.2 Primary composition of overall residual waste

The primary composition of the overall residual waste stream is calculated by combining the compositions of the two waste types in the proportions shown in the previous section. The compositions of the two waste types have been determined as follows:

  • general waste – as determined from survey results and shown in Section M3.1.1

  • kerbside collection – the assumed composition (see Appendix M1) for the kerbside collection was that determined by the sort-and-weigh audits undertaken at the Matamata Transfer Station in 2003/04 for the Ministry for the Environment SWAP Baseline Data Programme.

The primary composition of the overall residual waste stream is given in Table M3.7 and Figure M3.2. The secondary composition is given in Appendix M9.

Table M3.7: Primary composition of overall residual waste, 20–26 November 2007

Primary category % of total Tonnes/week
Paper 12.2% 11.7
Plastics 12.4% 12.0
Putrescibles 21.6% 20.8
Ferrous metals 7.5% 7.3
Non-ferrous metals 0.7% 0.7
Glass 5.0% 4.8
Textiles 5.4% 5.2
Nappies and sanitary 6.2% 6.0
Rubble 14.1% 13.6
Timber 13.9% 13.4
Rubber 0.3% 0.3
Potentially hazardous 0.6% 0.6
Total 100% 96.3

Figure M3.2: Primary composition of overall residual waste, 20–26 November 2007

Putrescible material comprised the largest primary classification of the overall residual waste stream, with 22 per cent of the total. A large proportion of the putrescible material was kitchen waste in kerbside collections. Rubble and timber were the second largest components, with 14 per cent of the total.

M3.3 Discussion and analysis

M3.3.1 C&D waste

Loads of waste generated by C&D activities (see Section 2.6 for the taxonomy of C&D waste ) were identified during the visual survey of the general waste stream. Kerbside collections, the waste stream other than general waste disposed of at the facility, contain negligible quantities of C&D waste. The quantity of C&D waste in the overall residual waste stream is calculated in Table M3.8.

Table M3.8: C&D waste, 20–26 November 2007

Total C&D waste in general waste 29.9 tonnes (from Table M3.2)
Overall residual waste 96.3 tonnes (from Table M3.6)
C&D waste as proportion of overall residual waste 31%

Table M3.8 shows that C&D waste comprised 31 per cent, by weight, of the overall residual waste.

M3.3.2 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 considered to be most relevant to the waste disposed of at the transfer station during the 20–26 November 2007 survey period are discussed below.

M3.3.2.1 Weather before and during the survey period

The November audit took place in early summer during a period of warm, sunny weather. Vegetative growth and gardening and agricultural activity would have been at a peak at this time. Construction activity would also have been at a peak, having been slowed by a very wet winter. This may have resulted in increased green waste and C&D waste being generated.

During the previous August audit the green waste drop-off area at the transfer station was often flooded, resulting in substantial quantities of green waste being disposed of in the tipping shed instead of at the drop-off area. During the November audit the green waste drop-off area was functioning normally. No loads were diverted to the tipping shed and therefore it would be expected that less green waste was disposed of during this survey period compared with the previous survey in August 2007. This appears to be the case, given that the percentage of green waste in the overall residual waste (3.2 per cent, see Appendix M9) is less than that recorded in the August 2007 audit (5.4 per cent, see Appendix M5).

M3.3.2.2 Economic conditions

Economic conditions in Waikato for the September 2007 quarter were generally subdued. The following comes from the National Bank regional trends report.7

Economic prospects for Waikato households slowed in September. The region recorded the second largest fall in house sales in the quarter, dropping 23 percent from June. Retail sales eased 1.5 percent, contrasting a small rise nationally. In addition, new car registrations dropped 1.1 percent and the number of residential dwelling approvals eased 4.7 percent. Employment in the region retraced 1.7 percent, coinciding with a 7.6 percent drop in job advertising. On the flip-side, Waikato recorded a 4.3 percent rise in the number of commercial construction consents issued (–4.7 percent nationally) and a 1.5 percent rise in accommodation guest nights. Rural real estate sales outstripped the nation-wide benchmarks, for both lifestyle blocks and large farm sales.

The combined result of these factors on waste generation and disposal during the survey period can not be estimated.

M3.3.2.3 Individual waste generators

The quantity of waste disposed of at the Matamata Transfer Station is sufficiently small for the composition to be changed significantly by the waste disposal behaviour of a single waste generator. This was shown in the November audit by a single load of manufacturing waste from a Tauranga explosives manufacturer containing over half of all the plastics in ICI loads, significantly increasing the proportion of plastics in ICI waste.