Landfill 2011 Seminar, 18 - 20 October, Durban, KwaZulu-Natal

180 Pages·2011·11.52 MB·English

by  Document Transformation Technologies

Keynote Address: Towards Appropriate Contaminant Containment Standards
K Legge ............................................................................................................................................. Not available
Composition of Waste Landfilled at Metropolitan Landfills and the Impact of the New Draft Waste Regulations
C C Wise, R C Emery and J A Coetzee ............................................................................................................... 1
An Overview of ENER-G Systems Experience with Landfill Gas Utilisation Projects in South Africa
D Cornish ............................................................................................................................................................. 11
Climatic Influences on Landfill Gas Extraction, with a Unique Comparison of Typical Performance
between Landfills Located in the Highveld and KZN Coastal Regions
B J Barratt, B L Jewaskiewitz and B L Mills ........................................................................................................ 16
Buffer Zones: The Long Term Interface
L Moodley, R Winn and J Parkin ........................................................................................................................ 24
Asphalt Liners in Landfill Construction
T Egloffstein and G Burkhardt ............................................................................................................................ 34
Landfill Gas Extraction Schemes - A Contractor's Viewpoint
J Butt ................................................................................................................................................................... 43
Drainage Sand Bulk Sampling a New Lined Residue Disposal Facility
I Nyirenda and C van Renssen .......................................................................................................................... 55
Geosynthetic Clay Liners (GCLs) – The Effects of Peel Strength on Performance
C MacKenzie and N du Toit ................................................................................................................................ 64
Addressing an Integrated Approach to the use of Alternative Technologies as an Economically Viable
Alternative to Landfill
C Whyte .............................................................................................................................................................. 73
Denitrification of Treated Landfill Leachate using MBT Waste as a Carbon Source: The Bisasar Rd
Test Cells
Z Hussain, N Sawyerr and C Trois .................................................................................................... Not available
Why Spend Money on Independent CQA Services during the Installation of Geosynthetic Lining Systems?
B L Mills and B L Jewaskiewitz ........................................................................................................................... 83
Economic Comparison of Landfilling with and without Anaerobic Pre-Treatment
G Burkhardt and T Egloffstein ............................................................................................................................ 94
Landfill Leachate Treatability
L J Strachan, H D Robinson and L R Gravelet-Blondin ................................................................................... 104
Behaviour of Baling-Wrapping MSW Landfill Application in Spain
J M Baldasano ................................................................................................................................................... 114
GCLs: The Buffelsdraai Landfill Experience
G J Payne .......................................................................................................................................... Not available
Design and Construction of a Deep Upstream Groundwater Cut-off Trench
J Shamrock, J Glendinning, J Mzisa and H Janse van Rensburg .................................................... Abstract only
eThekwini Municipality: Electron Road Waste Management Facility Presentation
C Wise ............................................................................................................................................... Not available
Mechanical Biological Treatment (MBT) Presentation
R Lombard ......................................................................................................................................... Not available
Slope Stability of Liners and Covers Workshop
R Thiel ................................................................................................................................................ Presentation
A Sustainable Mineral Barrier Option
M Naismith, E Timmermans and H Mulleneers ............................................................................................... 170

Proceedings of the LANDFILL 2011 Seminar, “Waste Management Facilities – The New Order” 18 – 20 October 2011
Proceedings ISBN Number: 978-1-920017-52-1 Durban, South Africa
Produced by: Document Transformation Technologies cc
DAY 3 : Thursday DAY 2 : Wednesday DAY 1 : Tuesday
20 October 2011 19 October 2011 18 October 2011
Denitrification of treated landfill leachate using MBT
waste as a carbon source: The Bisasar Rd Test Cells Registration
(Z Hussain, N Sawyerr and Dr C Trois)
Tea
Why Spend Money on Independent CQA Services
Keynote Address: Towards
During the Installation of Geosynthetic Lining Systems?
(BL Mills and BL Jewaskiewitz) Appropriate Contaminant
Containment Standards
Kelvin Legge
Composition of Waste Landfilled at
Economic Comparison of Landfilling with and without Metropolitan Landfills and the Impact o
Anaerobic Pre-Treatment the New Draft Waste Regulations
(G Burkhardt and Dr T Egloffstein) (CC Wise, RC Emery and
JA Coetzee)
An Overview of ENER-G Systems
Experience with Landfill Gas Utilisation
Tea Tea
Projects in South Africa
(D Cornish)
Climatic Influences on Landfill Gas
Extraction, with a Unique Comparison
Landfill Leachate Treatability of Typical Performance Between
(LJ Strachan, HD Robinson and LR Gravelet- Landfills Located in the Highveld and
Blondin) KZN Coastal Regions
(BJ Barratt, BL Jewaskiewitz and
BL Mills)
Behaviour of Baling-Wrapping MSW Landfill Application
Buffer Zones: The Long Term Interface
in Spain
(L Moodley, R Winn and J Parkin)
(Dr José M Baldasano)
GCLs: The Buffelsdraai Landfill Experience Lunch
(GJ Payne)
Sponsored By Wilson & Pass
Lunch
Sponsored By Lunch Asphalt Liners in Landfill Construction
(Dr T Egloffstein and G Burkhardt)
Bosch Stemele Sponsored By Aquatan
(Pty) Ltd
Design and Construction of a Deep Upstream
Landfill Gas Extraction Schemes - A
Groundwater Cutoff Trench
Contractor's Viewpoint
(J Shamrock, J Glendinning, J Mzisa and
(J Butt)
H Janse van Rensburg)
eThekwini Municipality: Electron Road Waste Drainage Sand Bulk Sampling a New
Management Facility Presentation Lined Residue Disposal Facility
(C Wise) (I Nyirenda and C van Renssen)
Mechanical Biological Treatment (MBT) Presentation
Tea
(R Lombard)
Geosynthetic Clay Liners (GCLs) – The
Effects of Peel Strength on
Performance
(C MacKenzie and N du Toit)
Addressing an Integrated Approach to
the use of Alternative Technologies as
an Economically Viable Alternative to
Landfill
(C Whyte)
Cocktails
Drinks Sponsored By Barloworld
Landfill Interest Group Seminar
18 to 20 October 2011
Final Programme
Session 1 Session 2 Session 3
08:00 09:00 Session Chairman: John Parkin 12:50 Session Chairman: Logan Moodley 15:50 Session Chairman: Geoff Purnell
18:00 +
09:00 09:30 13:50 16:10
09:30 10:30 11:05 11:40 12:15 13:50 14:30 15:10 16:10 16:50
10:30 11:05 11:40 12:15 12:50 14:30 15:10 15:50 16:50 17:30
Session 4 Session 5 Session 6
Session Chairman: 10:10 Session Chairman: Colin Redman 12:30 Session Chairman:
16:00
10:30 13:30
08:10 08:50 09:30 10:30 11:10 11:50 13:30 14:10 14:50
08:50 09:30 10:10 11:10 11:50 12:30 14:10 14:50 15:30
Session 7 Session 8
Session Chairman: Peter Davies 10:10 Session Chairman: Peter Davies 12:30
10:30 13:30
08:15 10:30
2011-09-13: Final
10:10 12:30
Slope Stability of Liners and Slope Stability of Liners and
Covers Workshop Covers Workshop
Rick Thiel Rick Thiel
COMPOSITION OF WASTE LANDFILLED
AT METROPOLITAN LANDFILLS AND
THE IMPACT OF THE NEW DRAFT
WASTE REGULATIONS

Wise C C*, Emery R C* and Coetzee J A*

* Jeffares & Green (Pty) Ltd. P.O.Box 38561, Pinelands, 7430, Tel: [phone];
E-mail:
2 EXISTING WASTE CHARACTERISATION STUDIES

A number of waste characterisation studies have been undertaken within metropolitan areas in
the last 10 to 15 years. Most of these have been focused on establishing the amount of
recyclables available in waste streams from various income groups in order to determine the
viability of initiating recycling programmes. As such these studies take representative samples
from various areas (generally domestic waste with some commercial waste) and divide it into its
various waste fractions. These include Ingerop (1999), KV3 et al. (2004), Gibb (2008), Ball
(2003), Ball (2004), Haultec (1998) and GreenEng (2010). Each of these studies have been
useful for their intended purpose, but are generator- based and are thus focused on the
breakdown within the waste streams and not the actual quantity that’s is landfilled. There are
fewer waste characterisations that attempt to analyse the composition of the waste actually
landfilled. This is understandable given the complexity and difficulty of such a task.

However, four studies have been identified that are specifically landfill-based characterisation.
These are:
1. Ball (2001): Landfill Salvager Survey. Report for the Greater Johannesburg Metropolitan
Council.
2. PNDA et. al. (2007): Strategic Road Map Phase 2 for Pikitup.
3. Akhile Consortium (2010): Section 78(3) Analysis for the Solid Waste Department, City
of Cape Town, Status Quo Report.
4. GreenEng / Jeffares & Green (2010): Analysis of the Bisasar Road Landfill weighbridge
data for the sizing of Electron Road Transfer Station.

Of these four, the three most recent studies PNDA et al (2007), Akhile (2010) and GreenEng
(2010) were analysed in more detail as they were considered more recent.

A summary of the purpose, assumptions and limitations of each of these studies follows.

2.1 Pikitup Strategic Road Map, Phase 2 (2007)
This study was focused primarily on an analysis of the waste currently going to landfill with the
aim of identifying and quantifying specific streams for diversion. It was a comprehensive study
that included a summary of the composition of waste landfilled to Municipal landfills in
Johannesburg. The characterisation of the household waste was based on KV3 et al. (2004),
while the remaining quantities were derived from weighbridge data. Some assumptions were
made with regard to the composition of non-domestic streams (such as illegal dumping and
street cleaning), but these quantities are relatively small and the assumptions would not
significantly affect the general conclusions drawn. The data used was for the 2005/2006
financial year.

2.2 Section 78(3) review for the City of Cape Town, Status Quo report
This study was also focused on the waste being landfilled at Municipal sites in an attempt to
quantify the waste fraction that could be diverted for beneficiation. The characterisation of the
household waste was based on Gibb (2008), while the other fractions were derived from
weighbridge data. It should be noted that the definition of recyclables in the household waste
characterisation study included all plastic and paper even if it was contaminated. This study also
looked at hazardous waste, which was quantified based on an analysis of the weighbridge data
(for commercial and industrial hazardous waste) and Gibb (2008) for household hazardous
waste. The quantities were determined for the 2008/2009 financial year.

2.3 Bisasar Road Landfill Waste Characterisation, Durban Solid Waste
This study was undertaken by GreenEng for Jeffares & Green (Pty) Ltd in order to accurately
determine the size of the new Electron Road Transfer station. It looked at weighbridge data
from 2006 until 2010 and established an average for each of the major waste streams. It was
2
however not the intention of the study to break down the household waste stream further (i.e
into recyclables, garden etc.).

3 SUMMARY OF RESULTS FROM EXISTING LANDFILL-BASED
CHARACTERISATION STUDIES

The results from the three different landfill-based waste characterisations are summarised and
presented here.

3.1 Pikitup Strategic Road Map, Phase 2 (2007)
The Strategic Road Map study categorised the waste in the landfill, based on the collection
mechanism. The following categories were thus used; Collection Vehicles, Street Cleaning,
Illegal Dumping, Drop offs, Informal Settlements, Bulk, Builders Rubble and Greens. However,
each of these categories was divided into various fractions such as recyclables, garden refuse,
putrescibles etc. This data was thus collated to provide an estimated waste characterisation of
the waste landfilled for the 2005/2006 financial year, as shown in Table 1. The report at the time
allowed for 15% greens in the household waste. However, since then greens are not allowed to
be disposed of in wheelie bins. The data was thus adjusted to only allow for 2% greens in
household waste, assuming some residents will “hide” greens in their wheelie bins.

Table 1: Estimated waste characterisation (by mass) for waste landfilled in Municipal landfill
sites in Johannesburg for the 2005/2006 financial year (adapted from PDNA et al. 2007)

Annual Mass
Landfilled
(t/yr x 1000)
Recyclables 206.1 13.4%
Putrecibles 126.1 8.2%
Greens and Garden 166.0 10.8%
Fines/residue 25.3 14.7%
Misc. & other 351.3 22.9%
Compacted bulk 37.2 2.4%
Builders' rubble 420.8 27.5%
Total 153.0

This data was compared with the Pikitup IWMP which showed a greens percentage for
2009/2010 as 9% of the total waste landfilled, which compares well with the data in Table 1 as it
allows for some greens diversion that has been taking place.

3.2 City of Cape Town Section 78(3) Review (2010)
This study characterised the waste landfilled on Municipal Landfill sites according to the new
Waste Act classification system. There was therefore a defined split between hazardous, inert
and general waste. General waste was further split between domestic and
commercial/industrial. A summary of the estimated waste characterisation as reported in that
study for the 2008/2009 financial year is provided in Table 2. It must be noted that this study
indicated that this data should be used with caution as the basic underlying assumptions were
applicable for the purposes of that study and may not apply for other purposes.

3
Table 2: Estimated waste characterisation (by mass) for waste landfilled in Municipal landfill
sites in Cape Town for the 2008/2009 financial year (Akhile et al. 2010)

Annual Mass
Landfilled
(t/yr x 1000)
General 1,4 92%
Household (incl. informal settlements) 571 36%
Recyclables 39 2%
Fod 84 5%
Other 148 9%
Street and area cleaning (excl. Builders rubble) 94 6%
Trade (commercial & industrial, excl hazardous) 301 19%
Inert Waste 479 30%
Builders rubble 349 22%
Greens directly to landfill as free waste 31 2%
Household greens (incl. informal) 99 6%
Hazardous 132 8%
Household 41 3%
Industrial 6 4%
Business & Commercial 25 2%
Total 1,57

3.3 Bisasar Road Landfill Waste Characterisation (2010)

This study was based only on the weighbridge data and was therefore a course estimate than
the previous two studies. Nonetheless, some of the comparisons are useful for further analysis.
The categories that were used in the characterisation were based on the classification at the
weighbridge, e.g. Durban Solid Waste vehicles, builders’ rubble, mixed loads etc. The average
for the 4 years, 2007 until 2010 are presented in Table 3.

Table 3: Average waste characterisation (by mass) for waste landfilled in Bisasar landfill site in
Durban for the period from 2007 until 2010 (GreenEng et al. 2010)

Annual Mass
Landfilled
  (t/yr x 1000)  
DSW Loads 417.8 38.0%
General Solid Waste 69.7 6.3%
Garden Refuse 36.6 3.3%
Builder's Rubble 107.6 9.8%
Mixed Loads 13.4 1.2%
Sand & Cover Mat. 418.8 38.1%
Tyres 1.0 0.1%
Light Refuse 0.2 0.0%
Other 3.7 3.1%
Total 1098.8

4
4 COMPARISON

As can be noted, the categories used for the waste characterisation were different in each of the
studies, which made a direct comparison difficult. In particular, the general waste fraction for the
Durban data was not further categorised into recyclables and putrescibles. Thus, only the
Johannesburg and Cape Town data could be compared by grouping the various waste fractions
into 5 broad categories, namely; recyclables, non-green organics (putrescibles, food and other
organics excluding greens), builders rubble (which included sand), greens (garden refuse and
other greens from parks etc.) and other. This was considered sufficient for the purposes of this
study as they represent the major waste fractions that would be diverted from landfill. The
comparison of the waste categorisation for Johannesburg and Cape Town are presented in
Table 4.

Table 4: Average waste characterisation (by mass) for waste landfilled in Johannesburg
and Cape Town

Cape Town Johannesburg
  (2008/2009) (2005/2006)
Annual Mass Annual Mass
Landfilled Landfilled
(t/yr x 1000) (t/yr x 1000)
Recyclables 39.2 21.5% 206.1 13.4%
Non-green organics 152.3 9.7% 126.1 8.2%
Greens and Garden 129.9 8.2% 166.0 10.8%
Builders' rubble 348.8 22.1% 420.8 27.5%
Other 606.5 38.5% 613.9 40.0%
TOTAL 1576.7 1532.9

The differences between the data for each of the waste fractions is discussed briefly.

4.1 Recyclables
Although it may appear that Cape Town generates more recyclables, the reason for the higher
apparent figure is that the methodology used in the household waste characterisation study
(Gibb 2008) included portions of the fines, which appeared to be paper or plastic, in the paper
and plastic categories. As such the amount of recyclables tended to be over-estimated.

4.2 Non- green Organics
The percentage of non-green organics are relatively similar with Cape Town at 9.7% and
Johannesburg at 8.2%. It must however be noted that the Cape Town figure excludes organic
(non-hazardous) special wastes (approx. 37, 000 tons/year) that is landfilled at the Vissershok
H:h site. That same waste fraction in Johannesburg would be landfilled at one of the private
sites and was thus taken out of the analysis for comparison. It should be noted that this fraction
however has a high diversion and beneficiation value.

4.3 Greens and Garden Waste
It would appear that Johannesburg (10.8%) landfills slightly more green waste than Cape Town
(8.2%). This could however be attributed to the Johannesburg data being slightly older
(2005/2006) and thus does not make allowance for the diversion measures that Pikitup have
subsequently initiated. For example, Cape Town’s 2008/2009 figures show that they are
diverting approximately 67,000 tons/year of green waste by means of a chipping contract,
representing a diversion of 35% of the estimate mass of green generated.
5
4.4 Builders Rubble
The mass of builders rubble tends to vary quite significantly from year to year as the building
industry fluctuates. Thus a comparison over different financial years is not ideal. However, the
difference between mass of builders rubble landfilled in Cape Town (22.1%) and Johannesburg
(27.5%) is considered to be relatively close given that the figures were recorded two years
apart.

5 AIRSPACE CONSUMED BY WASTE CATEGORIES

Although most waste characterisation is normally undertaken by means of mass, the volume
that the waste consumes in the landfill is more relevant when it comes to determining the life of
the landfill. The waste characterisations, as shown in Table 4 were converted to estimated
landfill volumes by means of the average landfill densities shown in Table 5, obtained from de
Wit (2009).

Table 5: Average landfill compaction densities for various waste fractions (de Wit, 2009)

Density
3
kg/m
Glas 830
Plastic 326
Builders Rubble 1502
Paper 606
Cans 20
Grens 20
Wet waste (food etc.) 900

3
The landfilled density of all other wastes was assumed to be 800 kg/m .

Using the household recyclables breakdown from Gibb (2008) and KV3 (2004), the weighted
3
average density of recyclables on landfill was calculated as 512 kg/m for Cape Town and
3
540 kg/m for Johannesburg. The percentage of each waste fraction landfilled by volume could
thus be calculated and is shown along with the percentage by mass for Cape Town and
Johannesburg in Figures 1 and 2.

Figure 1: Estimated waste characterisation (by mass and volume) for waste landfilled in
Municipal landfill sites in Cape Town for the 2008/2009 financial year

6
Figure 2: Estimated waste characterisation (by mass and volume) for waste landfilled in
Municipal landfill sites in Johannesburg for the 2005/2006 financial year

5.1 Greens
The most striking result is that greens and garden refuse, although relatively small with regards
to mass, make up a significant portion by volume. As such it is evident that, even though the
figures for Johannesburg be an over estimate for the current situation (due to the data
preceding some waste diversion initiatives), there is no doubt that the diversion of greens would
not make a significant impact with respect to mass, but would make a far-reaching impact on
extending the lifespan of a landfill.

5.2 Builders Rubble
Builders’ rubble, although making up a large portion with respect to mass, has less on an impact
on the landfill airspace consumed. Certainly there is significant merit in diverting builders’ rubble
from landfill sites, but that will not have as significant an impact on the life of the landfill as
would greens.

5.3 Recyclables
Recyclables are generally considered a prized waste stream for diversion, primarily because of
the value attached to that waste. This data also shows that recyclables can contribute to a
relatively large portion of the annual landfill airspace consumed.

5.4 Tyres (supplementary analysis to graphs in Figure 1 and 2)
Waste tyres has for many years been considered a significant problem on landfill sites. The
Bisasar Road data (see Table 3) recorded the mass of waste tyre separately and was thus used
to determine the percentage of the annual airspace that is consumed by tyres.
3
The bulk density of waste tyres has been previously reported to be between 350 kg/m and
3
500 kg/m (Wallingford, 2005). For the purposes of this study it was assumed the no waste
3
collects between the tyres on a landfill and thus a conservative landfill density of 350 kg/m was
used.

In 2007, 1,777 tons of tyres were disposed of on the Bisasar Road landfill. Using the landfill
densities in Table 5, the percentage by volume of the total airspace consumed by tyres was
0.4%.
Furthermore, the South African Tyre Recycling Process Company (SATRP) reports that the
larger Cape Town area produces about 12,000 tons of waste tyres per year, of which 3,000 tons
per year are recycled. Assuming the remaining 9,000 tons are landfilled, this figure would
constitute 1.0% of the City’s landfill airspace.

Thus, the data appears to indicate that waste tyres do not consume as much landfill airspace as
is commonly thought.
7
6 NEW DRAFT WASTE REGULATIONS AND STANDARDS

6.1 Greens
The Draft National Standard for Disposal of Waste to Landfill (Clause 5(1)) has set targets for
the diversion of a number of particular waste streams. The majority of these are hazardous
waste, with the exception of tyres and greens. The effect of these targets on future landfill
airspace was calculated based on the results of this estimated waste characterisation.

A proposed target has been set to divert 25% (from baseline) of garden waste in 5 years and
50% in 10 years. Using the data presented in Figures 1 and 2, the impact that this would have
on landfill airspace for Cape Town and Johannesburg is shown in Table 6.

Table 6: Estimated landfill airspace savings (by volume) if Draft National Standard for Disposal
of Waste to Landfill targets are achieved for diversion of Green waste
Landfill Airspace Savings
Greens Diversion Rate Cape Town Johannesburg
25% (5 year target) 6.6% 8.6%
50% (10 year target) 13.1% 17.3%

It can thus be estimated that if the 10 year target for greens is achieved (50% diversion) then
landfill lifespans could potentially be extended by between 13% and 17%.

6.2 Recyclables
The Domestic Waste Collection Standard (DEA, 2011) states (Clause 4.1) that “All domestic
waste must be sorted at source (i.e. the -households) in all Metropolitan and secondary cities”.
There is thus strong pressure for Metropolitan municipalities to initiate a system to divert
recyclables from landfill. Although many studies calculate the financial viability of at-source
separation and recycling initiatives based on the income from sales of recyclables, a very
important consideration is the financial benefit of landfill airspace savings.

The landfill airspace savings for Johannesburg and Cape Town were estimated assuming that
either 25% or 50% of the recyclables are diverted from landfill. This is shown in Table 7.

Table 7: Estimated landfill airspace savings (by volume) for 25% and 50% recyclables diversion
Landfill Airspace Savings
Recyclables
Diversion Rate Cape Town Johannesburg
25% 6.7% 4.0%
50% 13.4% 7.0%

It can thus be estimated that a diversion of 50% of the recyclables (which is relatively difficult to
achieve) would result in extending landfill lifespans by between 7% and 13%.

6.3 Summary
Based on the estimates presented here, a 50% diversion of green waste has almost twice as
much impact on extending the life of a landfill than if 50% of recyclables can be diverted. One
has to also consider how easy it would be to divert greens as opposed to recyclables. The
breakdown of the green waste sources for Cape Town and Johannesburg is given in Table 8.
8