K2.1 General waste
K2.1.1 Primary composition of general waste
The primary composition of the general waste is presented in Table K2.1 and Figure K2.1. The secondary composition, which includes all 22 categories, is given in Appendix K2.
Table K2.1: Primary composition of general waste, 17–23 September 2007
|Primary category||% of total |
(±95% confidence level)
|Nappies and sanitary||6.2||(±2.7)||0.7|
Figure K2.1: Primary composition of general waste, 17–23 September 2007
Putrescible material was the largest single component of the general waste, comprising 25 per cent of the total. Over half of the putrescible material was food waste, from both households and businesses. Plastics, rubble and timber comprised similar proportions of the total, from 12 to 13 per cent.
K2.1.2 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 207 loads of general waste. This included waste from construction and demolition (C&D), industrial/commercial/institutional (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 11.5 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 K2.2 shows the percentage of loads originating from each activity, the percentage of total weight, and the tonnes per week.
Table K2.2: Activity source of general waste, 17–23 September 2007
|Activity source||No. of loads surveyed||% of loads||% of total weight||Tonnes/ week|
|Construction and demolition||15||7.2||22.3||2.6|
|Landscaping and earthworks||11||5.3||6.9||0.8|
Residential activity was the source of nearly two-thirds of all loads of waste, but these loads only accounted for slightly over one-third 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. About a quarter of all loads were generated by ICI activity, and these loads accounted for 34 per cent of the total weight. C&D loads, while representing only 7 per cent of all general waste loads, accounted for over 22 per cent of the total weight. Waste from landscaping activity generated 5 per cent of loads and 7 per cent of the total weight.
K2.1.3 Primary composition of general waste, by activity source
The primary composition of the four activity sources of general waste is shown in Table K2.3. The secondary composition and margins of error are given in Appendix K3.
Table K2.3: Primary composition of general waste, by activity source, 17–23 September 2007
|Primary category||C&D |
|Nappies and sanitary||0.2||9.3||0.3||8.1|
Timber and rubble together comprised most of the C&D waste (78 per cent). ICI waste was more heterogeneous, with no single material comprising more than 23 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 (77 per cent), with rubble (mainly soil) comprising about 17 per cent. The largest component of residential waste was putrescible material (29 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.
K2.1.4 General waste, by vehicle type
For each vehicle load of waste disposed of on the tipping floor, the vehicle type was recorded. Table K2.4 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 K2.4: General waste, by vehicle type, 17–23 September 2007
|Vehicle type||No. of loads||% of loads||% of weight||Tonnes/week|
No front-loader trucks, gantry trucks1 or huka trucks disposed of waste during the survey period. A single compactor truck used the facility, but because it was carrying kerbside collections it is not included in this analysis of general waste. Over half of the loads disposed of on the tipping floor were carried by cars, but car loads accounted for only 22 per cent of the total weight. Many of these car loads comprised a small number of domestic rubbish bags. Trailers represented 32 per cent of all vehicle loads, but these loads accounted for over half of the total weight.
K2.1.5 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 K2.5. The secondary composition is shown in Appendix K4.
Table K2.5: Primary composition of general waste, by vehicle type, 17–23 September 2007
|Primary category||Car |
|Other truck |
|Nappies and sanitary||9.4||9.5||3.2|
K2.2 Overall waste to landfill
K2.2.1 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 these vehicles. The amount of glass disposed of to landfill was based on the survey records because most of the glass entering the facility was stockpiled.
Table K2.6: Waste types to landfill, 17–23 September 2007
|Waste type||% of weight||Tonnes/week|
A total of 15 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 15 tonnes disposed of during the week, nearly 80 per cent was general waste. The general waste included the drop-off of domestic refuse by many residents.
K2.2.2 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 composition of the three different waste types has been determined as follows:
general waste – as determined from survey results and shown in Section K2.1.1
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 K2.7 and Figure K2.2. The secondary composition is given in Appendix K5.
Table K2.7: Primary composition of overall waste, 17–23 September 2007
|Primary category||% of total||Tonnes/week|
|Nappies and sanitary||6.3||0.9|
Figure K2.2: Primary composition of overall waste, 17–23 September 2007
Putrescible material comprised the largest primary classification of the overall waste stream, with over a quarter of the total. A large proportion of the putrescible material was kitchen/food waste in kerbside refuse and ICI refuse. Paper, plastics, glass, timber and rubble all comprised similar proportions of the overall waste, from 9.3 to 11.4 per cent.
K2.3 Discussion and analysis
K2.3.1 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, contain 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 K2.8.
Table K2.8: C&D waste, 17–23 September 2007
|Total C&D waste in general waste||2.6 tonnes (from Table K2.2)|
|Overall waste to landfill||14.6 tonnes (from Table K2.6)|
|C&D waste as proportion of overall waste to landfill||17.8%|
Table K2.8 shows that C&D waste comprised 17.8 per cent, by weight, of the overall waste to landfill.
K2.3.2 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 relevant to the waste disposed of during the 17–23 September 2007 survey period are discussed below.
K184.108.40.206 Weather before and during the survey period
The September audit took place at the end of a relatively dry winter. The NIWA National Climate Summary for August 2007 states: “Rainfall was less than 50 percent (half) of normal in many eastern regions from southern Wairarapa to Otago, as well as Nelson”. This could have affected waste generation related to gardening and agricultural activity, given that vegetative growth would have been slowed by the conditions, resulting in less green waste being generated. The abnormally dry weather conditions could also have resulted in increased construction activity.
K220.127.116.11 Economic conditions
There are no economic activity reports available specifically for the Kaikoura region. However, in the June 2007 quarter both Nelson–Marlborough and Canterbury recorded small drops in economic activity and house sales.2 Trends for commercial and residential building consents were reversed in Nelson–Marlborough compared to Canterbury, so no assumptions can be made regarding construction activity in Kaikoura.
K18.104.22.168 Tourism activity
Tourism is a major contributor to the Kaikoura economy and the tourism sector can be expected to be a major waste generator. However, September is a period of relatively low tourism activity, so it can be expected that waste volumes in September will be smaller than at other times of the year.
K22.214.171.124 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. For example, the ICI component of the general waste stream had an unusually high proportion of textiles – nearly 12 per cent (Table K2.3). Almost half of the textiles were carpet and underlay contained in a single trailer load of waste. 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.
1 Gantry bins are commonly used for the removal of waste from construction sites, industrial sites or residential properties. Gantry bins are left at the site until removed by a purpose-built vehicle. The most common gantry bins have a capacity of 9 cubic metres, but smaller and larger bins are available.