| |
Contents
of December 1998
EDITORIAL
LETTERS
NEWS
INSPIRATION
'Anthro'
architecture - Kim Sacks Gallery
INSULT
Lantana
camara - One of the world's ten worst weeds
INFORMATION TECHNOLOGY
TREE OF THE ISSUE
FEATURES
Millennium Public Spaces Competition
Catering for disabled people
Building with demolition waste
Alternative sewage solutions
Saldanha Steel - an industrial
sculpture
-----
EDITORIAL
The end of
another year and The Urban Green File continues to do well, largely thanks to the support
of our advertisers but also thanks to our readers who phone in with comments and questions
- and make use of the products and services that we advertise. I wish that more of you
would, however, put your comments on paper so that we can carry them in Opinion Pole. Many
people have made mention of Henning Rasmuss’ excellent, thought-provoking commentary
on the Ponte controversy, in the Sep/Oct issue, but have not put their thoughts down on
paper. The Urban Green File strives to be an interactive journal and, although we succeed
to a certain extent, it would be nice to have even more critical input from our readers.
Hans Wilreker encouraged us, also in the Sep/Oct issue, to be more interactive while the
project is at concept stage. Criticism after the event has much less value than when there
is still a possibility that a valid idea could actually be included in a project. Ponte is
at concept stage and it is, questionably, a project about urban renewal - an important
issue in our journal. What is your opinion about the suggested ‘recycling’ of
Johannesburg’s well known landmark?
The end of
the year means that we have, sadly, to bid farewell to our Editorial Advisory Committee
and to thank them for their time, suggestions and their interest in the journal. We will
certainly be keeping contact with them in the future - and hope to be able to draw, for
example, on Henning’s writing skills and Chris Brooker’s expertise in the field
of environmental engineering, in the near future.
This is our
‘waste and recycling’ issue in which we look at the use of construction waste in
low cost housing and alternative sewage disposal systems There are also a number of
advertorials in our Products & Services section touching on different waste ‘issues’
which are being solved with new technology. Saldanha Steel was the centre of one of South
Africa’s largest environmental controversies and we would like to encourage
architects and environmental planners, alike, to comment on the building in its West Coast
surrounds.
We are
losing the services of Brand Smit who has been with us for the last six months and thank
him for the difference he has made to the smooth functioning of our office environment. We
wish all our advertisers and readers a prosperous New Year!
-----
LETTERS
Ponte Justice
Centre proposal - catalyst for inner city renewal
DDV
Landscape Design Group responds to the critique by Henning Rasmuss in the Sep/Oct issue of
The Urban Green File. Willem Punt and Neil Eitzen of DDV, landscape architects for the
Ponte Justice Centre proposal, gave Gerald Garner their views on the value of the project.
"The
conversion of Ponte into a justice facility will be a catalyst for inner-city
revitalisation," say Punt and Eitzen. They argue that Rasmuss is only concerned with
the building as an isolated object, as opposed to Ponte as a place within a highly complex
urban organism. "The developer has made a commitment to the people of Hillbrow and
Yeoville to upgrade the adjacent public spaces for the community’s benefit as part of
the conversion. The facility will also include a number of law courts and other public
amenities, making it a truly public place, with the prison itself higher up in the
building," explains Punt.
The
government has asked private businesses to come up with various models for prisons and
Ponte is designed as a privately owned inner-city court and prison which eliminates the
need to transport prisoners to and from a court which is further afield, with the
associated risk of escape. The government will rent space for each prisoner from the
developer. At this stage, the whole idea is conceptual as government has not yet released
the official tender documents.
The proposed
conversion has been planned as an important node, integrated into an urban renewal
framework. Ponte is not a prison but a justice facility, which should act as a catalyst to
improve public transport, amenities and spaces. Currently, the area surrounding Ponte is
severely dilapidated with the adjacent on-ramp to Siemert / Sivewright avenues known as
one of the ‘rape spots’ of Johannesburg. The developer has promised to take care
of the public land outside the property boundaries - Donald MacKay Park, the municipal
reservoirs, Primrose Street to the intersection with Tudhope, and Lily Street to the
intersection with Abel Road - on behalf of the council. This will include the installation
of multi-purpose sports surfaces, a public park and square and a maintenance programme for
the precinct.
The
landscape architects view Ponte as an important node, linking the open space system along
Mervyn King ridge as well as pedestrian movement from Hillbrow to the taxi rank, Technikon
and Ellis Park precinct on the other side of the building. At present, the building acts
as a barrier and, according to the landscape architects, by developing proper public
spaces around Ponte, the place will become the important node that it should be in the
city context. "This will also improve the value of nearby residential properties and,
as opposed to Rasmuss’ belief that no one would want to live next to a prison, it may
be quite an attractive address," says Punt. "It will be a positive investment in
the city, improving the environment and adding public amenities, which the municipality
cannot afford to develop or maintain on its own."
As for the
symbolic impact such a visible prison will have on the city, Punt says: "Ponte will
be a visual ‘symbol of social justice’ in South Africa."
It has been
established that an EIA is not required because the area is already zoned as high density
residential. However, the urban design framework, which has been developed as part of the
proposal, addresses the impacts of the development on the urban context.
The Urban
Green File reported on the source of the Jukskei River (and therefore the Limpopo river),
which is situated in a small pump room on the municipal reservoir site adjacent to Ponte,
in the July / August 1997 issue. We express the hope that the symbolic and natural value
of the river will not be ignored in this development.
Overloading is
the problem
Response to
Bonza Chalets article, page 23, Sep/Oct issue of The Urban Green File
Earthworm
toilets are a good idea but one should be careful not to overload natural systems. There
are many vermiloos in use in America and even Alaska. They do work well.
There are
many variations on the vermiloo. All systems are for use by families and not groups.
"Overloading" is the conclusion that I come to when reading Sara Sparks’ A
learning experience with earthworm toilets. As a researcher doing my Ph D on composting
toilets, I would like to comment on the earthworm itself. The worm that I assume has been
used in this case is able to multiply very rapidly. The mean cocoon production per worm is
0, 35 per day and the mean number of hatchlings per cocoon is 2, 7 with a mean incubation
period of 23 days. Maturity is between 40-60 days in a system like a toilet - but can be
much earlier. Earthworms are not predators and will not eat anything that is alive -
neither plants nor animals. There has never been anything recorded about dominant worms
consuming other worms and there are many research papers to support this. Earthworms do,
however, live in peace with many micro-organisms in their digestive systems.
Where did
the people of Lime Acres Wildlife Club get their information? Surely, no supplier would
have supplied this information? We must start to take care of our environment and I think
that worm toilets are but one way of handling our human waste safely. I am also looking
into toilet systems making use of worms but am not yet satisfied that I have a system that
can cope with our climate or the numbers of people at public facilities.
In this
case, I think the blame has been placed on the wrong person or persons. I do, however,
think that the number of worms supplied to start up with was not sufficient.
Ina Meyer - MSc Zoology (Earthworms)
Sara Sparks’
reply to Ina Meyer
I was most
grateful to Ina Meyer for her response to my article and I do apologise for any misleading
information that I may have included about the earthworm.
My source of
information, which may imply that earthworms eat live food, is Senior Biology -
Standard 9.
This book is by Du Toit, Van Rensburg, Du Toit, Botha, Volschenk, Van der Westhuizen, De
Koch, Niebuhr. NASOU. National Book Printers. Nov 1986, page 100: "Usually one or two
of the egg cells in the cocoon develop into new earthworms - the others are used as
food."
Unknown pollution
source contaminates dam
The entrance
dam at the Kyalami Grand Prix Circuit in Gauteng was recently upgraded at significant cost
by rebuilding the dam wall to shallower angles and enlarging the capacity of the spillway
to ensure compliance with safety criteria. The dam acts as a flood and silt attenuation
measure for the runoff generated by the upstream high density commercial developments.
Care was
taken to enhance the visual characteristics of the dam by expanding the environmental
attraction. During construction, the fish in the dam were housed in a temporary pool,
protected by shade cloth, to ensure their survival, while after completion of the wall and
spillway, the surrounds were grassed and landscaped and a central island equipped for use
by duck and bird life.
The
completed construction was put to the first real test during a cloud burst which occurred
over the area on 5 November 1998. The dam stood up well, the spillway capacity was not
exceeded and no erosion occurred due to the energy breakers installed at the outlet.
However,
this idyllic setting was transformed over the weekend of 7/8 November 1998, when an
unidentified upstream user deposited an unknown quantity of waste into the river system.
The fish in the dam were killed and the water and surrounding area were stained black by
the pollution. Subsequent analysis has not revealed the pollutant which caused the death
of the fish but leads are being followed.
Alan Parrock- ARQ Specialist Engineers
-----
NEWS
Landscape and Art
A
report on the IFLA Conference - Athens 1998 by Gwen Breedlove
The
Panhellenic Association of Landscape Architects hosted the 1998 International Federation
of Landscape Architects’ (IFLA) Conference. George L Anagnostopoulos, President of
the Association, recalled the IFLA Conference in South Africa (Cape Town, September 1993)
and sent his best wishes to all the SA landscape architects.
South
African landscape architects, Ann Sutton - the grande dame of landscape architecture in
SA, and Gwen Breedlove, attended the Conference and the latter, who is in private practice
and a senior lecturer in the Department of Architecture and Landscape Architecture at the
University of Pretoria, delivered a paper entitled: Landscape Aesthetics - an
understanding of the biophysical environment.
The
Conference invited designers, artists and writers interested in landscape to participate
and the programme included over 80 distinguished speakers from all parts of the world. It
provided a forum for examining landscape art within the framework of art in general and
presented an opportunity for multi-disciplinary discussions on the role that landscape, as
an aesthetic object, plays in landscape design, architecture, painting, sculpture and
literature. The majority of the papers explored the landscape in its role as a source of
pleasure to humans - whether as a symbol, as an image, as a food source or as inspiration
for creativity. Although not always recognised by the speakers, human intervention into
the landscape was generally presented as being justified to meet these anthropocentric
intentions.
It was
evident from most of the papers, that the balance between cultural expression and the
intrinsic authenticity of natural systems, remains unexplored by most landscape
architects. If we are to be effective, the challenge for landscape architects, worldwide,
is to explore, understand and implement an equilibrium between human compulsions and a
functioning biophysical environment.
Lost City opens
as a botanical garden
When the
Lost City was conceived in 1989, one of the first major projects was the establishment of
a nursery to provide plants for the hundreds of hectares of landscaping on the site. Today
the garden contains around 3 000 different plant species and a specialist collection of
more than 400 different types of palms. In a planting programme that started in 1991, more
than 6000 mature trees were transplanted.
Patrick
Watson, who was responsible for the landscaping of the gardens, had a very unorthodox way
of placing plants and according to Gordon Kershaw, senior horticulturist for the Top Turf
Group, ‘throwing sticks’ was his way of planting, so as to emulate seed
dispersal in nature, as opposed to a meticulous pre-conceived plan. The result is an
organised, though ‘wild’ garden.
The garden
is divided into 22 different forests and 80% of the plants are indigenous. The trees are
marked with national tree numbers and a catalogue of trees will be made available to
tourists in order for them to log the various species. The catalogue will give tree
numbers, botanical and common names, country of origin and medicinal and other uses for
the plants. Says Philip Georgas, Director of Operations, Sun City Resort: "The
planting at Sun City is scientifically important and our aim is to have it recognised as
the largest National Botanical Garden in the southern hemisphere." Hundreds of
species of birds and other fauna have been attracted by the planting and the specialised
feeding programme.
Walking
tours have been inaugurated at the gardens. ‘The Boabab Tour’ passes through dry
areas of indigenous planting to the boabab forest of transplanted mature trees. The ‘Beach
Tour’ includes tropical and coastal plants from various regions, including the Wild
Coast. ‘The Spider Web Trail’ runs through exotic and indigenous cycad
plantations and tropical rain forest. Flamingoes and other waterfowl are among the birds
to be seen on this route. ‘The Lost City Crock Pit Tour’ features desert theme
plants represented by Euphorbia and Aloe species, and ‘The Cascades Gardens to Water
World Tour’ takes tourists through a mature forest of bamboo, figs, Shefflera and
Chorisa speciosa, amongst many others.
Educational
birding facility - Johannesburg Zoo
The Sasol
Wing, a new educational birding facility, was recently opened at the Johannesburg Zoo. The
addition of the thatched roof facility, which can be used for lectures or exhibitions,
enlarges the Zoo’s educational role and revitalises the walk-through aviary. Sasol
through its sponsorship of the new wing aims to enhance environmental responsibility and
concern for birds amongst members of the public.
New signage
on the aviary provides information on and illustrations of the birds in the aviary which
makes the experience of bird identification fun for children and adults alike. The
director of the Zoo, Pat Condy, said that it was important to stimulate these good
feelings as they were part of the educational process. Prominent ornithologist Geoff
Lockwood commented on the value of the walk-through aviary saying that a lot of people,
who did not have the opportunity to get close enough to birds to really appreciate them,
were given the opportunity in this walk-through situation.
The Bryandale
Wetland primary school / community project
The story of
this exemplary project started with Bryandale primary school entering the Jukskei River
Eco-monitoring Competition and being allocated the Cumberland Dam in Bryanston to monitor.
The children went to Cottesmore Road Park in Bryanston and found what they incorrectly
assumed to be the Cumberland Dam. It was a badly degraded area of open space with bluegum
infestation and there was no water in the dam - which had, in fact, been the Douglasdale
Dam and had burst sometime in the ‘80s. Deputy head Rosemary Fowkes then conceived
the remarkably bold idea of rebuilding the dam and her tenacity and drive, with a lot of
hard work from the children and help from the community, saw this project through to the
official opening of the so called ‘Bryandale Wetland’ on 17 October this year.
The main
sponsors of the project were Brian and Liz Matthews of Douglasdale Dairy, the Tony and
Lizette Lewis Foundation, Rand Water, PPC, engineering consultants Leech Price Associates
in the person of Chris Brooker who provided the design and monitored the building of the
project and Jonathan Fergusson of the Top Turf Group who provided the landscaping design
and managed the whole project. Erroll Nuper of ‘Worth It’ was the contractor who
provided equipment and services at a discounted rate and landscape consultant Patrick
Watson helped with the choice of trees. Many other smaller sponsorships were collected by
the children from businesses and private individuals in the community.
Chris
Brooker said that their initial plan was to re-instate the previous dam to its full height
but the DWAF suggested that a series of wetlands running down the valley would be more
acceptable. The main ‘pool’ was designed as an homogenous earth-filled dam with
the base of the wall being designed so that it could be raised to the full height of the
old dam, if this was required in the future. The material from the old wall was tested by
geotechnical engineers Schwartz Tromp & Associates, who also gave their services free
of charge, and found to be adequate for use in the rebuilding. The foundations were
located on bedrock and the wall was made wide enough to be resistant to erosion. The
improvement in water quality is already in evidence with the reeds starting to spread
across the dam and trapping the silt. Brooker said that with on-going fund raising, they
were hoping to keep a stretch of water open in the lower pool to attract waterfowl.
"The
dam doesn’t have enough volume for significant flood attenuation but the spillway is
designed to contain the 5-year flood and the vegetation below the second pool will pass
the flood without significant damage. The badly degraded wetland upstream is already
rehabilitating naturally because we stopped the headcut erosion which was occurring, by
refilling the donga that was acting as a drain and drying out the wetland," commented
Brooker. Brooker also said that the Wastewater Department of the Eastern Metropolitan
Local Council needed to be commended for their very rapid response to sewer problems that
were experienced in the valley.
At the
official opening of the wetland, Fowkes complimented Fergusson, Brooker and Nuper on their
excellent commitment to the project. "We will be monitoring the project as a school,
removing invasives and litter, and hope to install a fence some time next year," said
Fowkes. The school children are already doing projects about the fauna and flora of
wetlands and the area will be an invaluable outdoor classroom for present and future
generations of school children, as well as a valuable piece of open space in the rapidly
urbanising area.
1998 Concrete
Manufacturers Association Awards for Excellence
The winners
of the CMA Premier Awards for Excellence received their trophies at a gala banquet in
Johannesburg in September. The awards which are held every two years recognise excellent
use of precast concrete products and the competition attracted 146 entries this year. The
Premier Award for concrete masonry was won by Daspoort Station in Pretoria - entered by
Watson Tile & Concrete. The Premier Award for concrete roof tiles was won by Bryanston
Wedge in Johannesburg - entered by Marley Roofing. The International Conference Centre in
Durban - entered by Corobrik, won the Premier Award for paving, while Sur le Monde
residential development in Bishopscourt, Cape Town - entered by Terraforce, won the
Premier Award for retaining blocks.
1998 Eduplant
Competition winner
Over the
past four years, the sponsor, Eskom Community Development, has invested R 1,4 million in
Eduplant, to the benefit of over 900 schools, 1520 teachers and trainers, a conservative
estimate of 450, 000 students and countless community members. This year, the winning
school was Nansindlela Primary, a culturally diverse school in Kwazulu-Natal. The school’s
efforts at growing organic vegetables and fruit, harvesting and conserving water,
irrigating with a bicycle pedal powered pump, recycling waste, improving the soil and
recognising permaculture as an ideal tool for outcomes based education, ensured that it
won the first prize of R 4000. They are also to donate their surplus organic produce to a
nearby hospital caring for Aids patients. The annual Eduplant competition is organised by
Trees for Africa.
1998 Survey of
Environmental Reporting in SA
KPMG, one of
the world’s leading business and advisory firms, in conjunction with the Department
of Accounting at Pretoria University, have conducted a survey into environmental reporting
in South Africa as it appears in the annual reports of 514 (97% of) JSE listed companies
and 10 public entities. The survey demonstrates a steady improvement in the quantity and
quality of environmental reporting in South Africa. The Gold Award was won by Trans Natal
Coal/ Ingwe Coal, the Silver by Western Deep Levels and the Bronze by Samancor.
The vast
majority of companies that are on the Top 50 list, ranked according to environmental
reporting performance, are in the mining sector and this is due to the more stringent
requirements in this high impact sector - to implement Environmental Management Programmes
and set aside environmental rehabilitation funds. Amongst the significant findings to
emerge from the study is a strengthening of environmental governance structures within
companies. A higher percentage of companies have assigned environmental responsibilities
to executive and senior management. Wayne Visser, manager of the environmental unit at
KPMG, says, although this survey only covers annual reports, there are plans to extend the
survey to cover separate environmental reports, next year.
Toyota Prius
Energy conservation and
recyclability
The Toyota Prius is the world’s first internal combustion/electric hybrid
passenger car to enter volume production. By focussing on energy conservation and the
reduction of CO2 emissions, the Prius achieves nearly twice the fuel efficiency of
conventional gasoline engine cars and cuts HC, CO and NOx emissions to about one tenth of
the amounts set by current Japanese pollution regulations. Toyota has designed the Prius
in order to achieve 90% recyclability by weight by the year 2000 and has taken assertive
steps to reduce environmentally harmful substances such as lead.
-----
INSPIRATION
‘Anthro’
architecture - Kim Sacks Gallery
The Kim
Sacks Gallery in Rosebank, Johannesburg, is the culmination of the documentation of clay
architecture over the last 20 years by pottery artist Kim Sacks. Sacks designed the
gallery as an ‘anthro-building’ - a ‘human’ building where visitors
feel welcome, warm and sheltered, as well as a space to exhibit objects. The building is
built with cement and bricks and plastered to give a textured finish.
The front
door is approximately 150 years old and was imported from Zanzibar.
-----
INSULT
Lantana camara - One of
the world’s ten worst weeds
The common
Lantana is an exotic invader species in South Africa and it is a declared noxious weed. It
forms dense thickets replacing other exotics in gardens and indigenous plants in the wild,
increasing erosion and interfering with farming and forestry activities. It is a prolific
seeder and its small black berries are highly favoured by birds which spread it far and
wide. Gardeners, and many municipalities - it seems, are totally unaware of its harmful
characteristics and treat it as a precious addition to the urban garden to be nutured and
groomed, as in the adjacent picture.
The Urban
Green File spoke to Hildegard Klein of the Plant Protection Research Institute (PPRI)
about the latest developments in biological control methods for Lantana. She said that a
particular bug, a leaf-sucking insect, was awaiting approval from the Department of
Environmental Affairs and Tourism (DEAT), having previously been passed by the Department
of Agriculture, and was, at present, at Working for Water’s mass rearing station in
Mpumalanga, awaiting release. "The release of any organism outside its natural area
of distribution that is to be used for biological pest control" is one of the listed
activities that now requires a compulsory environmental report (with the possible
inclusion of an Environmental Impact Assessment) under the Environment Conservation Act -
and so the approval of the DEAT is required.
Lantana is
very difficult to eradicate and when it is hacked back by hand (a time-consuming and
difficult job), the stumps need to be painted with an environmentally safe herbicide -
which is often not effective, and re-infestation results. Klein says that there is no hope
that any one insect will be able to control Lantana and that is why the PPRI is
researching a number of possibilities: "The most we can hope for is that each
biological measure will contribute to weakening the plant, so that it reaches the stage
where it won’t coppice and can then be controlled by other, environmentally safe,
means."
-----
TREE OF THE ISSUE
Acacia xanthophloea
Commonly
known as the fever tree
Louis
Meintjes of Bergsig Nursery has chosen the Fever Tree, with its amazing yellow-green bark,
as The Tree of the Issue. He calls it a majestic tree - the tree that you notice first in
a parkland situation because of the colour of its bark. He says that for a tree which is
associated with wet areas in the wild, it is remarkably drought tolerant and is only frost
tender when it is young. He warns that it might not do well out in the open in the colder
areas of Gauteng - if, however, there is a fair amount of vegetation around the tree, it
should cope. It provides a wonderful environment for birds and the Yellow Weavers favour
it for nesting purposes. "There are always birds in the tree," comments
Meintjes.
Meintjes has
seen Acacia xanthophloea do very well as a parking lot tree at the Kollonade shopping
centre in the north of Pretoria, while the specimens on the open lawns of the parkland on
the northern side of the Pretoria Botanical Gardens are his favourites in urban surrounds.
He advocates that the tree be used in ‘woodland’ groupings in landscaping - with
the trees 5 - 10 m apart from one another, or next to water because of the beautiful
reflections of the yellow trunks and branches. He says because the branches start high up,
and it is a relatively narrow tree, it is a good tree for the townhouse garden. It casts a
dappled shade, so plants do well underneath it.
It is a fast
growing tree and does particularly well with regular watering and fertilising - Meintjes
suggests 515 which releases slowly. He says that, ideally, the tree should only be planted
out into the landscape once it is 3 - 3,5 m high - or in nurseryman’s language, in a
50 l bag.
-----
INFORMATION TECHNOLOGY
Computer aided visual impact assessment
Computer
generated sketches enabled the architects of a Cape Town building to limit the visual
impact of the building.
Cape Town
has a rich history and numerous cultural influences reflected in its curious blend of
architectural styles. The city has carefully preserved its historical buildings in
conjunction with the building of modern high-rise office blocks. Examples of Edwardian,
Victorian and Cape Dutch buildings can be seen within the boundaries of the city, as well
as traditional, cobblestone streets and Islamic flavoured architecture, which adds to the
city’s atmosphere. Honouring this heritage is an ever-growing challenge for
architects working to create new structures in the city.
Conservation
efforts such as the Cape Town City Council’s Urban Conservation Unit ensure that
historically significant buildings are preserved, and new buildings do not interfere with
the ambience of the city. Such is the case with the Seapoint Conservation Area, which lies
near Cape Town’s popular Waterfront. It contains an array of architectural styles,
and has been undisturbed by new developments for a number of years.
However,
construction of a new luxury apartment complex, designed by Leon Smith Architects, began
in 1998. According to the Urban Conservation Unit’s guidelines, the 13-unit executive
apartment complex set within the historic area and on a sloping site overlooking the sea,
had to blend with the surrounding structures. The architects faced strict height
restrictions to prevent the new building from blocking the ocean view of other residents
in the neighbourhood. It was also subject to very tight boundary and building lines due to
the narrow streets and close confines of the community. Above all, the new structure had
to enhance the ‘eclectic’ aesthetics of the Sea Point Conservation Area.
To determine
the visual impact of the building, the architects prepared visualisation sketches,
utilising a combination of MicroStation, MicroStation TriForma and MicroStation
PowerDrafte. With their design fully modelled in 3D using MicroStation TriForma, the
architects scanned photographs of the site. The model was then simply superimposed on the
photographic image. The rendered result was photo-quality images of the completed project,
instantly communicating the contextual affect of the new building to people who were not
accustomed to mentally visualising architectural drawings. The architects could present
finished, easily understandable pictures of the new building, and how it would affect the
neighbourhood, to the client and the various councils that had to approve the
construction. Using this method, the model could easily be adjusted, in the case of
approval boards asking for alterations to the design.
-----
FEATURES
Millennium Public Spaces Competition
Finalists
in the squares and streets category
Finalists in
the ‘squares and streets/malls’ category of our public spaces competition,
sponsored by Enviro Elements/Townscape, are the Lower Marine Parade - Durban Beachfront,
and St Georges Mall and the Victoria & Alfred Waterfront in Cape Town. Subscribers who
wish to vote for the winner of the squares and streets category should fill in and fax the
ballot form, included with this issue, to The Urban Green File: (011) 482-3407.
Lower Marine Parade,
Durban Beachfront
This public space was entered into the competition by the City Engineer’s
Service Unit of the Durban North Central Local Council. In the late ‘80s, the Lower
Marine Parade was subject to a massive remodelling exercise, converting the road into a
decoratively paved and landscaped promenade from the Aquarium in the south to the Snake
Park in the north. The work included an integrated street furniture design and beachfront
signage system. The planning of the project was done by Revel Fox and Partners; the design
by the Urban Design Division of the City Engineers Department; the street furniture design
by Oberholzer & Van Papendorp; and the signage design by Monica Gobel.
The area
hosts a number of recreational activities including jogging, walking, cycling and
rollerblading, coupled with beach related activities. The majority of events held along
the Lower Marine Parade tend to be of a sporting nature and space is leased out by the
Recreation Department for special functions. Public events have included the Ocean Action
festival which promotes Durban’s image as an active recreational city. On New Years
Day, crowds of up to 33 000 have been estimated at the central beachfront.
Cycle stands
have been installed at the key commercial nodes situated along the main beaches. The area
is closed to private vehicles but parking pockets are located near all the activity nodes
and bus and taxi passengers can be off-loaded within easy walking distance. The public
space is linear and its primary relationship is to the beach, while there are strong
visual and movement linkages back to the central city. Recently, pedestrian routes to the
International Conference Centre have been enhanced through streetscape improvements and
signage.
When the
change of the road into a promenade was first mooted, surveys were conducted to reveal the
attitude of the community to such.a radical change while, at present, working groups
comprising councillors, municipal officials and representatives of the business community
discuss new developments in the area and aspects of management. The overall maintenance
responsibility lies with the Recreation Department. The area is patrolled regularly by the
City Police Department and closed circuit surveillance cameras have been installed to
allow for quick response in emergencies. Planting is maintained so that visibility is not
impeded.
St Georges Mall
The Design Services Branch of the City of Cape Town entered St Georges Mall
into the Open Spaces Competition. St Georges Street has existed as a public street, under
different names, since the earliest period of the original Dutch settlement. Its
conversion to a pedestrian mall began in the mid '80s and it now extends through the heart
of Cape Town for a distance of 700 m or ten city blocks. More than a hundred plane trees
have been planted along the Mall in avenue formation. Kiosks, seating and a water feature
have been provided at key points along the Mall. Thibault Square at its northern end has
been radically reconfigured and is an integral part of the Mall, which is the city’s
premier pedestrian realm, lying as it does in the heart of the retail shopping zone and
connecting the financial and office concentrations at its two ends. It also links museums
and places of interest in Government Avenue and the Gardens to the Foreshore and the
emerging tourist node of the former Power Station site.
The City
Council initiated the project and led the team of consultants and contractors, during the
design and construction phases. Revel Fox and Partners were responsible for the design and
consultant co-ordination, while Ian Ford and Associates did the landscape design in
conjunction with the City Council and the street furniture design was the responsibility
of Oberholzer and Van Papendorp. From the outset, every effort made to ensure that the
ultimate concept would fit into the existing urban context and a series of studies was
undertaken, surveying pedestrian and traffic movement, employment densities and
distribution of retail and other business functions in relation to St Georges Street,
while built form and sunlight studies culminated in development controls and design
guidelines for buildings lining the Mall. It has been declared a ‘Special Area’
within the City’s zoning scheme, to give better protection to buildings of value and
to influence the form of new development.
The Mall is
a multi-use area for commercial activity (both formal and informal shopping)
entertainment, strolling, drinking coffee, having a meal at a café under the trees or
just sitting on a bench. As a channel which facilitates pedestrian movement, it encourages
even businessmen to walk to meetings. The main mall is probably visited by at least 10 000
people during a lunch hour in good weather, with in excess of a million lunch hour visits
during a year. Police reservists patrol the Mall, particularly in the evenings. A task
team of municipal and business representatives are involved in programmes to combat crime
and grime.
The Victoria &
Alfred Waterfront
The V&A Waterfront has re-established the link between the City and the sea
and revitalised Cape Town’s historic working harbour into one of the country’s
most successful leisure and retail complexes, also comprising hotels, the UCT Business
School and future residential components. At concept stage, in the late ‘80s, a wide
spectrum of Cape Town’s organisations and interest groups were presented with the
V&A Waterfront Company’s development intentions. Now that the project is
established, the procedure for gaining public feedback on further
development
proposals is formally constituted in the form of the Waterfront Liaison Committee,
comprising members of public, private, professional and non-governmental organisations.
Working
harbour features that have been retained are the harbour tugs, the pilot and fishing boats
and the traffic to the synchrolift and dry dock. The V&A’s Public Space Network
has contributed to its success having embraced Cape Town’s ‘Greening of the City’
policy with its linear parks, tree-lined boulevards, and a landscape ‘web’ at a
local scale which includes squares, corridors, promenades and arcades. Treatment of these
spaces was influenced by historic harbour references, the harsh marine environment and
user need. Trees are used to celebrate gateways or building entrances, to frame views and
define axial routes, along with different paving textures and lighting. Street furniture,
particularly bollards, railings and lamp standards, also define spaces, directing traffic
movement and providing safety barriers. The Waterfront caters for all means of access - by
road, rail and air (helicopter pad). Roads cater for both the cyclist and pedestrian and
interlink to parking pockets, squares and water-edge promenades. Public transportation by
taxi and a dedicated bus service connects with the City’s transport networks.
In 1996,
there were 17,9 million visits to the Waterfront with over 80% of the annual visits made
by Capetonians. The V&A caters for mixed activities with its open space network
encouraging strolling, sitting, viewing, formal and informal entertainment, exhibitions,
sporting events and boating. It hosts a variety of entertainments such as large scale,
orchestral, jazz, ballet and choral singing events, while the walkways and squares are
frequented by buskers who are first auditioned to establish their ability to perform.
Organised sporting events have included the International Dragon Boat Regatta, the Mini
Rugby World Cup, Beach Volleyball championships, the Cricket Marathon, Basketball Day and
the Sports Climbing event. The Waterfront is also a primary educational destination.
The V&A
is managed as an estate and the manager and his team are responsible for all aspects -
including cleaning, security and maintenance of buildings and landscaping.
-----
Catering for disabled people
Access
to the natural environment - designing to include disabled people
"In our
rush to accommodate the needs of disabled people, we must not perpetuate the process of
social segregation. We should design all facilities for all people. With the extra
attention paid to designing for the use of all the senses, the facilities will be more
satisfying to all visitors and will result in more effective interpretation. In addition,
if we remove the barriers that are presently keeping disabled people from using our
facilities, we will have gone a long way towards reducing the handicaps these people
bear."
J Beechel -
a researcher who wrote his master’s thesis on access to American parks.
Carol Knoll
attended an Eco-Access workshop entitled ‘Environmental facilities, programmes and
resources that include disabled people’ at the Witwatersrand Botanical Gardens, spoke
to Rob and Julie Filmer of Eco-Access about their objectives and attended the launches of
two projects catering for varying disabilities - the Sasol Sensory Trail at Delta Park
(finalist in our Public Spaces Competition) and the Sasol bird hide and walkway at
Nylsvley. The ‘Reach for the Wild’ project at De Wildt Cheetah and Wildlife
Centre, which is at concept stage, will be designed as a fully inclusive facility.
"Eco-Access
is a holistic environmental organisation promoting access to nature and sustainable living
for all, through focussing on the inclusion of people with disabilities." These words
form the basis of the Eco-Access mission statement and the organisation’s philosophy
emphasises the importance of an environment that caters for the greatest cross-section of
people - young, old, frail, sickly, pregnant, mothers pushing prams, temporarily disabled,
as well as those with mobility and sensory problems and the mentally challenged.
Eco-Access promotes a balance between maintaining wilderness and creating access.
Rob Filmer
says: "The basic premise is to include access at the feasibility stage of the
project. Access for all will influence the positioning of the trail or facility and if the
correct position is chosen at concept stage, the costs can be kept down. Accessibility
should not be imposed on the design, as an afterthought, but should be a routine factor
considered during initial development activities. Universal design or the concept of
including everybody is not something that the nearest disabled person can give advice on,
as he will merely be designing for his own disability - there are disability specialists
who are trained to take a wide spectrum of needs into account."
According to
Rob, developers are loth to take the needs of disabled people into account because they
see the costs as being prohibitive. This, he says, stems from ignorance. The White Paper
on an Integrated Disability Strategy states that the increase in costs will be minimal,
between 0,2 - 0,5% of the project costs, if access is considered from the outset. Rob
points out that ramping is usually less expensive than steps and that the provision of
accessible parking bays, which are a non-negotiable, does not mean that the whole parking
lot needs to be paved or turfed (particularly where a natural ambience is important) but
merely the 3,5m widths of the designated parking bays and the access route to the
facility.
Talking
about the design of trails, Rob says that hand rails, as self-guiding mechanisms, are a
controversial issue for a number of reasons but that a tapping rail, a raised area along
the edge of a pathway, can be a useful self-guiding mechanism for a blind person with a
white cane and, depending on the gradient, the wheelchair user can brake his chair against
it. He says that hand rails can detract from the experience of sighted people,
particularly those in wheelchairs because their eyes are at the same height as the rail,
in a wilderness environment. "We work on maintaining a balance between wilderness and
access - and there are more sighted people than blind people," says Rob, while Julie
Filmer points out that a facility designed solely for disabled people is almost bound to
be a white elephant.
Another
problem with hand (guide) rails is the fact that they need maintenance as they are often
damaged by vandals, and metal rails rust with time. Children are inclined to swing on rope
rails and manilla rope sags when it is wet, making it uncomfortably low for use. "We
have looked into the different ropes that are available to find one that is soft on the
hands and yet thick enough. Plastic cabling cracks in the sun and steel piping is
sometimes too hot to hold in mid-summer. One also has to take into account the number of
people using the rail in relation to the costs. So far, we haven’t recommended hand
rails," comments Rob.
Signage
should be of the correct height for wheelchair users and this will also benefit children,
while the availability of audio (taped) information will benefit both the blind and the
illiterate. Aluminium plates of braille lettering attached to signs provide a marvellous
opportunity for vandals and the only solution here, according to Filmer, is to make the
facility as secure as possible - a well-used facility provides the on-going surveillance
that is needed to guard against vandalism. The front panel of a bird hide needs to be
adapted with a ‘knees projection’, so that a disabled birdwatcher can get closer
to the viewing panel, while the base of the viewing slot should be 980 mm from the floor.
"If you
can only afford one toilet at a facility, make sure that toilet is accessible - and it
needs to be a unisex toilet, so that the partner of the wheelchair bound person can
accompany him or her. The toilet can then also be used by a mother and her small son. The
National Building Regulations stipulate measurements for an accessible toilet and although
they are full of loopholes and difficult to read, they are likely to help designers rather
than hinder them. They are under revision at present and will, hopefully, be more
comprehensive," continues Rob. Howard Blenkenstein of the ‘Green Buildings for
Africa’ programme at the CSIR is working out an ‘environmentally friendly rating
system’ which includes accessibility.
The on-going
series of Eco-Access workshops is aimed at getting developers and designers, concerned
with the natural environment, to think about access through interacting with disabled
people, both wheelchair bound, visually impaired and deaf people, so as to learn their
needs. The workshops are held at the Witwatersrand Botanical Gardens in Roodepoort and the
reason for this, Julie says, is: ‘"When we have a function, this is one of the
few places we can come to without losing our integrity."
The Gardens
have regular tours which are based on sensory experience and, as part of the workshop that
I attended, environmental education officer Suzelle van der Westhuizen took us on one of
these. The requirement was that we were either blindfolded or in a wheelchair. We had the
opportunity of feeling the structure and texture of certain unusual, succulent plants such
as bottle plants, stone plants (Lithops), etc - and the sense of touch is heightened when
one is blindfolded. We went through the herb garden with regular guide, George Thupe, and
were encouraged to smell plants such as the Brown Salvia (Salvia africana lutea) and the
Wild Garlic (Tulbaghia violaceae), while he told us about their medicinal and other uses.
Regular
guided tours of school children and others, says van der Westhuizen, are encouraged to
feel things, to smell things, to listen attentively for sounds and even to taste certain
plants. We learnt that one of our party, Andre Manders, who has been blind from birth and
is in the South African blind cricket team, can tell from the taste of a grass stem what
kind of grass it is. Rob also encouraged us to put our ears against the trunk of a large
White Stinkwood to listen to the sap moving. (We were not certain whether this was tongue
in cheek?) The tree is over 100 years old and has wrinkles like an old man’s elbow.
He suggested that these sensory experiences were more important than learning the tree’s
scientific name but added that a little braille tag giving the name Celtis africana would
have been a nice addition.
The Filmers
pointed out aspects along the route, such as the wide pathways, explaining that these
allowed wheelchair users freedom of manoeuvreability while, at the same time, the
able-bodied could walk side-by-side along the paths, benefiting from being able to hold a
conversation as they walked. The occasional sleeper bridge was difficult for the
wheelchair users to cross. They commented that the shelf in the bird hide was at the wrong
height. The wooden benches and tables in the restaurant proved to be a weak point as their
design made them inaccessible to wheelchair users. They spoke of the newly built
accessible toilet, adjacent to the restaurant, saying that it was one of the best they had
seen because it was big enough for the wheelchair user to be able to close the door with
ease and even though the seat was not high enough to allow the user a comfortable transfer
from his wheelchair, this could be corrected with the use of a seat riser. "The fact
that wheelchairs are available for those not fit enough to walk through the Gardens is an
excellent aspect of this facility and there is a pamphlet in braille available at
reception," concluded Julie.
Eco-Access
gave input into the design of the Sasol Sensory Trail (See Sep/Oct 1998 issue of The Urban
Green File / e-urbangreen) at Delta Park in Johannesburg which was designed by architect
Michael Thomas. The Filmers mentioned aspects which had worked well and criticised others,
commenting very favourably on the hexagonal, smooth concrete, turning circles, while
expressing disappointment that the rails of the raised wooden deck were in the line of
sight of wheelchair users, but saying that there seemed to be no way around this in terms
of safety regulations. They praised the signage, done by John Roff, saying that it was
basic enough and very interactive with each sign related to a different sense, while his
guide booklet Awaken your senses gave just enough additional information. They pointed out
that the braille boards were at the wrong angle, making it awkward for braille readers to
reach their arms over them to read them (see photograph).
The ‘Reach
for the Wild’ project at De Wildt near Hartebeespoort Dam is on a relatively flat
site and is being designed in conjunction with a number of disability and wildlife
organisations. Its objective is to provide close contact with the wild through enclosures
of tame wild animals, birds and reptiles, tactile displays of eggs, nests and samples of
skin, sounds of the wild, impression of spoor, indigenous gardening demonstrations,
smelling of herbs and learning about their medicinal uses, and through information boards
in both braille and print. Julie says that the facility, for which the SA Veterinary
Association has raised the initial finance, will have no steps, the exhibits will be at
the right height for wheelchairs, the trail through the bush will be ramped and led by a
knowledgeable guide, the toilets in the Centre will be correctly designed and the counters
of the kiosks will be at the correct height. She says that there has been a lot of debate
about what comprises an accessible vehicle so that more ground can be covered at De Wildt
and some of the outer enclosures used for breeding programmes of endangered species and
rehabilitation of injured animals can be visited by all.
The Filmers
emphasise the need for marketing and advertising of facilities that cater for disabled
people. "We need to make sure that disabled people know that the facilities are there
so that they will be fully utilised ," concludes Rob.
-----
Building with demolition waste
The
use of construction demolition waste in the low cost housing environment
The low cost
housing environment is facing a number of challenges and with a backlog of roughly 3
million units, every possible avenue must be explored to increase the number of units
built and reduce the costs. This article refers, particularly, to the situation in the low
income housing developments in the Cato Manor / Chesterville area of Durban.
The reuse of
construction waste, principally concrete and brick material, offers a number of
advantages. Some of the factors motivating its use are the following:
•
The large quantities
of illegally dumped usable material. In Chesterville it is estimated that there is 20-30
000 tonnes of usable material. It is ironic that the community’s present environment
already contains the material to build it’s future.
•
The pressure on
land-fill sites. The primary dump site for this material in Durban is Bisasar Road, and
the 1995 prediction of a 30 year lifespan for this site has been recently revised to 14
years. It is predicted that waste will increase by 6% per annum, and a number of dump
sites are being forced to close because of health reasons. This is increasing the pressure
on existing sites, as well as encouraging illegal dumping.
•
The need for low-cost
building material of an acceptable standard. The single biggest inhibiting factor is
affordability. The bulk of the government subsidy is used on the site with very little
left over for the structure.
•
Conventional
technologies seldom promote the use of community based labour. In the main, current
materials are produced off-site and delivered with little or no community involvement.
From an
international perspective, South Africa is lagging behind industrialised nations in the
use of construction waste - very little building material is re-utilised. In Copenhagen,
± 80% of infrastructure materials are recycled and in Holland, ± 60%. In Australia and
America, there is extensive crushing and reuse of demolition material. In SA, asphalt
planings (from roads, etc) are largely reused locally but in the Chesterville area, the
largest percentage of dumped waste is, in fact, asphalt based road materials.
The most
basic form of reuse in SA is in the construction of informal settlement shacks, either
using brick and concrete waste mortared together or as a filling in the traditional wattle
and daub construction. Whilst this is the most economical method, it has little structural
integrity and design/production potential.
However, the
material can be easily sorted and crushed, and reused as an aggregate with a much higher
structural integrity and unlimited design/production potential.
The sorting
and crushing process is fairly straightforward. Kevin Gallagher of Concrete and Brick
Recyclers, in Durban, runs a successful operation. Material is delivered to Gallagher’s
site by contractors and dumped for a small charge. The material receives rudimentary
primary sorting by hand or payloader and is then passed through a crushing system. Small
material is passed through a power screen to remove the material that is too small for
crushing and the remainder is added to the larger material, which is initially crushed by
the primary jaw crusher. This is then fed through a secondary rotary impact crusher and
then onto a triple deck screen for sorting into the various aggregate sizes.
Crushing at
a centralised location has the advantages of a static plant but limits the source of
material, as demolition contractors will not travel far to dump the material. It also
means badly sorted material, as sorting is invariably not done on the construction site,
and often contains a lot of deleterious material which could affect the quality if not
effectively controlled.
Gallagher
has recently set up another plant at a dump site to maximise source material but the plant
costs are extremely high so this limits the number of sites that he can cover.
Crushing at
source with a mobile plant offers the best option but this requires the support of the
professional construction team. The building should be demolished in a planned manner that
suits the reuse options. Material can be crushed in an orderly sequence, thereby limiting
contamination, and preferably stored on the site for future use or transported directly to
a stockpile/user.
Some
variations on the use of the material include the following:
•
Road sub-base or final
surface. Durban Metro Roads Department laboratory has approved recycled aggregate for use
as a crusher run base with the proviso that it is monitored for consistency - possibly
with the addition of foamed bitumen as the binder for road construction where local soils
are not suitable for gravel roads.
•
Foundation and surface
bed aggregate. PCI (now the Cement and Concrete Institute - CCI) tests indicate that it is
an acceptable aggregate for most concrete strength requirements. A contractor has been
using the material successfully in the Chesterville area for the past two years.
•
Block manufacture. PCI
tests again indicate acceptability with certain conditions, namely pre-wetting and tests
for soluble salt content as this could affect the concrete. A number of local block yards
are using the material successfully and are producing blocks of adequate strengths with
minimal additional cement requirements. These blocks are being used in some of the housing
developments in the Chesterville area.
Community
involvement is also enhanced with the use of demolition waste. Gallagher allows the local
community to remove the scrap steel reinforcing for sale to scrap dealers and this
provides valuable income for out of work people. Primary hand sorting of deleterious
material, such as wood from window frames and plastic from roof underlay, can be done by
community members at the crushing plant or dump site. The material can be delivered to the
development site and the local community can produce the blocks for construction. The use
of suspect local soils in block manufacture can lead to under-strength blocks or the
excessive use of cement to obtain suitable strengths.
The primary
advantage of using recycled aggregate is cost savings. At the present limited scale of
production and use, the material is ± 25 % cheaper than conventional aggregates and it
could logically be even more cost effective if the use increases.
There are,
however, a number of factors inhibiting the effective growth in the use of the material -
such as the following:
•
Lack of awareness. Key
players (authorities, developers, contractors, communities) are not aware of these
recycled materials or their potential benefits.
•
Reluctance to specify.
Members of the professional team are reluctant to specify recycled materials because they
are afraid of trying something new and are not concerned about reducing costs.
•
Refusal to accept
moral responsibility. There is a tendency to pass the responsibility of the disposal of
material on to the demolition contractor whose primary motivation is lowest cost. This
leads directly to illegal dumping.
•
Questionable
competitive practice. Some primary materials suppliers are offering discounts to stop
contractors using recycled material. Recycling is in the interests of all. It deserves
some sort of support or protection.
Further
research is needed in the use, for example, of alternative binders such as foamed bitumen
and alternative technologies to suit these alternative binders which will promote
community involvement in production and construction.
In
conclusion, for the use of construction demolition waste to be successful, we need the
following:
•
Framework legislation
with clear minimum requirements for the use of secondary materials.
•
Community education
and community inclusion in the process to ensure acceptance and support.
•
A constructive,
progressive attitude on the part of all concerned parties.
-----
Alternative sewage solutions
As opposed
to the traditional ‘high’ and ‘low’ technology approach to sanitation
systems, more affordable alternative systems of an acceptable standard are becoming
available in South Africa.
According to
the Department of Water Affairs and Forestry (DWAF), existing approaches to sanitation are
not viable or affordable for the vast majority of people. In South Africa, it is estimated
that 12 million people do not have access to clean drinking water and 21 million people do
not have adequate sanitation. The ‘conventional’ water-borne ‘flush and
discharge’ system is being challenged by the concept of sustainability, in the search
for solutions. Could existing water-borne systems be made more sustainable? What is the
current view of sanitation experts about affordable technology options and what other
alternatives are there?
"Most
cities in the Third World cannot afford the necessary resources in terms of water, money
and institutional capacity, to provide a ‘flush-and-discharge’ system. The
conventional alternative is a ‘drop-and store device’, usually a pit toilet,
based on containment and indefinite storage of human excreta. Drop-and-store is often
regarded as an inferior, temporary solution compared with flush-and discharge,"
comments the Swedish International Development Cooperation Agency (SIDA).
The National
Sanitation Policy of 1996 states that "the basic level of service for a household is
a Ventilated Improved Pit (VIP) toilet, or its equivalent, as long as it meets the minimum
requirements of sturdiness, health benefits and environmental impact". However, VIP’s
(which are dry toilets) can be problematic if they are not properly positioned or
installed because of a lack of space for digging deep pits and difficult soil and
groundwater conditions. They are not always odour free and can be expensive to empty.
"The
sanitation sector in SA suffers from a number of peculiar problems in terms of
technology," states the National Sanitation Programme of 1998. "Firstly, a
‘missing middle’. Sanitation facilities, if they exist at all, are generally
either at the basic level of a pit latrine, ventilated or otherwise, or a fully
reticulated water-borne sewage system. Intermediate solutions - in terms of the country’s
stage of development - are seldom implemented. This missing middle is largely a result of
a prevailing reluctance by politicians, officials, consultants and sometimes households to
consider service levels below conventional water-borne sewage. This reluctance is fuelled
by examples of failed intermediate solutions, even if they have failed for reasons other
than the technology itself."
Water saving
technology addresses the problem of water consumption in toilet systems through the use of
water saving devices and the recycling of grey water. Eco-sanitation systems consider
human excreta to be a valuable resource for recycling. Different options exist in dealing
with liquids and sanitising solids. Examples to be explored are anaerobic, composting and
urine diversion. Most of these technologies have been used in other countries and are
being tested under South African conditions.
Eco-sanitation systems
One of the basic questions when designing an ‘eco-san’ system is
whether to divert the urine or to receive combined urine and faeces in a single
receptacle. If the latter approach is used, effective processing will, with few
exceptions, require later separation. The options are urine diversion, liquid separation
and combined processing. Ecological sanitation is concerned with the various ways of
destroying pathogens.
"Human
faeces, not urine, are responsible for most diseases (pathogens) spread by human excreta.
Methods like decomposition and dehydration are needed to sanitise faeces. When faeces
decompose, the different living things die and are broken down into smaller parts
rendering them harmless. Dehydration, or drying, of faeces is easier if they are not mixed
with urine and water. It is only then that the faeces can be safely recovered and
recycled." explains SIDA.
The time it
takes for all the organisms of the same type to die is referred to as the ‘die-off
rate’ and this varies for each pathogen. Temperature, moisture, nutrients, other
organisms, sunlight and pH affect the rate. Climate changes can affect the die-off rate or
artificial means such as solar heater fans can be utilised to speed up the die-off rate.
If detergents and chemicals are added to the natural eco-sanitation systems, they stop the
natural processes and cause bad smells which attract flies. If a system which is designed
for limited family usage is overburdened, the system will become dysfunctional.
Anaerobic systems
Anaerobic systems convert raw sewage by natural microbiological means into
carbon dioxide and methane gas, killing pathogens and leaving an inert sludge. The Deico
Mac Anaerobic Digestion Toilet System, marketed in South Africa, has a fifty eight day
retention period in which pathogens are killed and it operates either as a non-flush
system or as a mini-flush system. The airtight digestor equipped with a paddle agitator,
is initially filled with water when installed. Each time the toilet is utilised, the fresh
influent enters the digestor and displaces an equal amount of digested, neutral effluent
which is passed into to a soak-away. A ‘gas relief pipe’ relieves any gas
build-up.
This system
can be used in a variety of applications. For example, a High School in the Durban area,
with a three-storey building, installed the toilets on all the levels, suspending the
digestors on the higher levels. The odourless effluent is discharged down a pipe into a
‘small bore sewer’. Grey water then combines in this outlet and this is led,
into effluent drains under the playing fields providing a sustainable cheap fertiliser.
In 1993, O’Connell
Manthe & Partners investigated household effluent being pretreated in an anaerobic
system and thereafter discharged to small bore sewers together with household grey water.
This report found that the chance of blocked sewers was negligible and this would reduce
the required number of manholes for maintenance. Less material would be deposited into the
grit channel at the treatment works reducing the retention time, and less activated sludge
would be returned. The effective capacity of conventional treatment works would be
improved and these would be more economical to operate.
Composting toilets
Aerobic dry systems provide the right environment for the composting of human
waste - a similar process to the natural recycling of garden refuse into compost. The
system must provide evaporation capacity. Oxygen, moisture, heat and organic material are
required to enable the aerobic bacteria and microbes to recycle human waste.
The Enviro
Loo, non-flush dry sanitation system, operates by means of a combined processing system in
the receptacle as the solids dry. The liquid portion drains to the bottom of the
receptacle (a ‘water trap’) and is then evaporated and vented into the
atmosphere. Fresh ‘moist’ waste falls on top of a grid, a scoop system then
‘bulldozes’ the old drying waste down the grid separating the waste and
preventing contamination. Once the system is up and running, the dried matter is removed -
after a two to three year period - by this stage the pathogens should have died off.
The Enviro
Loo composting system needs to be installed in a position of maximum sunlight. The black
manhole cover is designed to achieve maximum heat absorption. Mark Letrobe of Enviro
Options says: "In South Africa’s hot climatic conditions, heat can be seen as a
resource to be utilised, whereas with the cold weather conditions overseas, composting
toilets have to use electricity to initiate the process."
This system
has varied applications from rural to urban. Etienne Bruwer of Greenhaus Architects in
Cape Town was concerned about water shortages and decided to install an Enviro Loo in his
urban residence because of the water conserving benefits of this system. He said that he
had problems installing the system as his north-facing house’s services were grouped
together on the southern side of house. The toilet needed to be installed on the north
side to receive sun. A solution was to use an extractor fan to facilitate the drying of
the faeces, which wasn’t ideal from an energy point of view. Bruwer added that this
problem also posed interesting architectural and aesthetic questions. Most eco-sanitation
options need heat to dry the faeces in the receptacle and in SA need to be installed on
the north side of houses. Ventilation pipes would have to be incorporated into the house
design so that they are aesthetically acceptable.
High activity microbe
powder
High activity aerobic microbes in a powder form, offer a convenient method of
decomposing sewage efficiently, removing odour problems and health risks due to fly
infestations. Crystal Clear Bio-Cleaner, has been used successfully in low technology
sewage systems in Southern Africa, such as composting toilets, for the past four years.
This microbe powder accelerates the breakdown of the organic material in the sewage,
converting the material to compost.
This microbe
technology is an affordable option for pit toilets, bucket systems, septic tanks and
conventional sewage plants.
Milton
Buchalter of Crystal Clear says that: "Due to financial limitations in many township
areas, improving sewage systems remains a serious problem. "In these areas residents
use expensive disinfectants that do not solve the sewage odour and fly problems. Use of
microbe powder in pit toilets has proved very successful at schools and remote army bases,
reducing solids and eliminating odours.
Earthworm toilets
Earthworms can be used for the break down of human waste in composting toilets.
They play a role in mixing, aerating, tearing apart and breaking down the contents of the
pile in the toilets processing vault. If the environment is favourable for them, they will
multiply, eating the malodorous organic matter, reducing bulk by approximately two thirds
and converting it into ‘vermicompost’. Earthworms have the ability to remove
pathogens.
It is
important to remember that earthworms are living organisms and need a balanced diet. Moist
conditions are favourable for the multiplying of earthworms - if their environment is too
dry, problems will occur.
Urine diversion
technology
Urine diversion means that the urine is diverted at source by a specially
designed toilet pedestal and is not mixed with the faeces. Urinals are complementary to
this system. A pit is not required and the entire structure may be constructed above
ground. The high temperature reached in the faeces receptacle ensures the desiccation of
the contents with rapid pathogenic die-off rate. The technology is based on the concept
that the human body produces faeces and urine separately and that they should be disposed
of separately and problems arise when the two are mixed.
Human
excreta is a resource: "The desiccated faecal matter, which is usually bulked up by
the addition of material like sawdust, wood shavings, dry sand or ash, makes a good soil
conditioner, and the diverted urine, when diluted in water, is a source of plant
fertiliser," says Aussie Austin of the CSIR Division of Building Technology. The
technology can also be applied to a flushing system, where the urine is separated and the
faeces conventionally treated in a water-borne system. This means a saving in treatment
costs.
The faeces
receptacle is solar heated by means of a metallic, black-painted cover flap. After human
defecation, a bulking agent is sprinkled on the faeces to help absorb moisture and prevent
odours. Water must not, under any circumstances, be used in this system. Paper and other
material used for cleansing should be stored in a separate container and disposed of by
burning.
-----
Saldanha Steel - an industrial sculpture
An
industrial sculpture - Saldanha Steel
Inspired by
the natural hues of the West Coast landscape and the massive Gothic architecture of the
Middle Ages, the Saldanha Steel plant is a work of industrial sculpture, built with care
for the environment.
During 1995,
the proposed development of a steel plant for Saldanha Steel, close to the internationally
important Saldanha Langebaan aquatic system and wetlands and the West Coast National Park,
was met with a public outcry. The idea of an unsightly industrial monstrosity, with the
associated air and water pollution, was considered, by many, to be repulsive (and some
still see it that way).
After
intensive consultation with concerned parties and the developer, the Western Cape
Government agreed to allow Saldanha Steel to establish the proposed steel plant if certain
conditions were adhered to, some of which were:
•
that the proposed
plant be re-located to a site within the application area, but 2 km further away from the
bay;
•
that an Environmental
Monitoring Committee (EMC) be established and empowered to intervene if the conditions of
approval were not adhered to;
•
that the visual impact
of the structure be softened by design, as suggested by Saldanha Steel;
•
that no hazardous
waste materials, containing high concentrates of heavy metal (H:H) elements, be stored or
disposed of on the site but that these be dumped inland at an appropriate and licensed
site;
•
that a draft
Environmental Management Plan be drawn up by Saldanha Steel and submitted to the EMC.
Architecture
A Visual Impact Assessment, prepared by Cave Klapwijk & Associates during
1995, before the implementation of the project, highlighted the ‘low visual
absorbtion capacity of the landscape’ - it is flat and almost featureless, and
therefore architectural aspects such as the colour of the building had to be complementary
to the landscape. As the plant was so huge in scale - 1,2 km long and 106 m at its highest
point, the fear was that it would dominate the entire west coast landscape, an unsightly
scar in an otherwise tranquil and ecologically sensitive setting. However, it was this
scale and desolate landscape that inspired Meiring to design buildings reminiscent of a
Gothic cathedral surrounded by a medieval village.
The
functional layout of the factory was predetermined by Saldanha Steel and the architect’s
role was to improve the visual appearance of the building. Meiring reduced the ‘massiveness’
of the building to a more human scale by ‘breaking up’ the buildings into square
towers topped with pyramids. The dynamic play of light on the building, especially at
sunrise and sunset, creates dramatic and ever-changing shadow patterns. Some of the
segments are purely visual with only 90% of the floor space actually being used. Saldanha
Steel will, however, utilise the extra space for other purposes in the future. The entire
plant is covered in a cladding material and roofed with pitched roofs (pyramid shaped).
The roofs of all the turrets are pitched at 450 angles, except for the Corex tower which
has a pitch of 600. Meiring originally planned the turrets for ventilation purposes but
the plant, in the end, did not need extra ventilation and these were built, largely, for
aesthetic effect.
In a paper
delivered at the Industrial Development Engineering Association (IDEA) symposium on 28
October 1998, Meiring explained his design approach:
"Why
should industry be hidden? I asked myself when the controversy over the mooted steel plant
broke. Of course there was the real fear of pollution. This is a fragile environment, a
wetland, beautiful and precious with its tremendous birdlife and a real tourist attraction
with its incomparable wildflower show in late winter and early spring. But, there was no
way in which such a plant could be hidden from view as the terrain is flat and gentle with
low rolling hills.
The terrain,
the light and the somewhat desolate landscape reminded me of how the European landscape
might have looked in the tenth, eleventh and twelfth centuries when the great cathedrals
were built. They became landmarks that actually attracted people to come closer to look
and marvel at these structures. I was inspired by the thought that a large plant could
actually become such a landmark.
The
colouring is a soft beige / white that changes colour in the ever-changing light of the
West Coast. The awareness of protecting and even celebrating the environment was very
contagious. Workers started taking photographs of the developing plant in the mist, in the
early morning and even in the rain, which at times would sweep across the landscape.
Some of the
areas surrounding the steel plant are earmarked for more industrial development, and I do
believe that a standard has been set and indeed the local authority is adamant that both
the ecology as well as the architecture will play significant roles in future
development."
Environmental
Management Model (EMM) and Plan (EMP)
The government, developer and concerned parties decided during 1995 that the
requirements of the proposed development and those of environmental protection could best
be accommodated by introducing an Environmental Monitoring System which comprised an
Environmental Monitoring Committee (EMC), representing local interest groups, an
Environmental Working Committee (EWC), advised by appropriately selected environmental
specialists, an Environmental Management Plan (EMP) and an Environmental Management
Schedule (EMS).
The
Environmental Management Plan (EMP), prepared by Prof Willem van Riet and Allan Heydorn,
deals with aspects such as pollution control and rehabilitation during and after
construction. A second EMP compiled by Africa Enviromental Solutions deals with the
factory in its operational phase. Contractors are committed to the EMP and have to follow
the instructions carefully so as not to disturb the environment while building. For
example, some of the criteria contractors have to adhere to relating to hazardous
substances and solid waste are:
•
the Environmental
Control Co-ordinator must be informed of all activities that involve the use of hazardous
substances to allow for prompt response in the event of a spill or release;
•
the contractor must
provide details of his spill response plan in the event of any spills of fuel, oils,
solvents, paints or other hazardous materials;
•
the contractor must
ensure the protection of workers against spray exposure;
•
any spill water must
be contained immediately using appropriate containment equipment;
•
sumps receiving oil or
oily water must not be allowed to overflow;
•
vehicles or machines
are to be refuelled only at designated refuelling locations and the same applies to any
oil or lubricant changes.
Landscape
rehabilitation
The value of the West Cape Floristic Region required the landscape to be
rehabilitated during and after construction. The Environmental Management Plan (EMP)
stated that the destruction of the West Cape Floristic Region biome should be prevented
within the Saldanha Steel property boundaries and an indigenous landscape recreated. The
EMP identified vegetation loss, dust amelioration and visual intrusion as major concerns.
Vegetation loss was addressed by transplant-ing and seeding a mix of plants native to the
area, while dust was prevented by establishing temporary vegetation in areas that were to
be continuously disturbed, and in other areas by seeding or planting a mix of permanent
plants.
The
landscape architects and flora specialist divided the site into 19 separate landscape
areas based on physical boundaries, as well as their functioning during the construction
and operation phases. They further identified six landscape types, which represented
different levels of rehabilitation during the construction phase. These landscape types
are: protected, temporary, functional, ecological, wetland and aesthetic. For example the
‘temporary’ landscape type required the sowing of soil stabilising pioneer
species while the ‘wetland’ landscape type required the eradication of exotics,
spreading of topsoil, sowing of soil stabilising indigenous pioneer species, sowing of
additional perennial species, planting of bulbs and planting of additional aquatic plants.
These actions were then monitored to determine the status of the vegetation establishment
and to recommend remedial action in areas which did not meet the requirements of the
monitoring programme.
Waste disposal and
water conservation
An area of about 220 ha is used for the disposal of waste materials. All the
slag disposal sites are lined and fitted with leak detection systems. Saldanha Steel
processes all the Corex slag for use in the cement industry. Corex and Midrex sludges and
Conarc dust are granulated and either recycled into the process or sold off to the cement
industry.
A monitoring
station north of the Saldanha Steel site ensures continuous air quality by monitoring SO2
(sulphur dioxide) levels and PM10 dust (particles smaller than 10 micron). Groundwater
samples are taken every three months at 28 boreholes, which were drilled on and adjacent
to the site. The boreholes cover strategic areas such as the slag disposal sites, the
solid waste disposal site, the evaporation ponds, the raw materials storage area and the
stormwater collection pond.
The plant
operates on a ‘zero discharge water system’ and a closed-circuit air-cooling
system reduces water consumption by 30% and enables the plant not to exceed its usage of
12 000m3 per day.
The
stormwater system comprises three ponds. The first concrete-lined pond captures the first
4 mm down-flush of stormwater containing most of the dust deposited on roofs, roads and
other paved areas. Water by-passing the concrete-lined pond is collected in a plastic
(HDPE-lined) pond and recovered for use in the process. An unlined pond further downstream
takes care of any excess water which cannot be accommodated in the other two.
Some of the
facts
•
The building is 1,2 km
long and 106 m at its highest point.
•
1 500 bulbs were
rescued from the site prior to construction and stored in nurseries on site and in
Stellenbosch, and replanted as part of the revegetation programme.
•
Two tonnes of seed
were harvested from the immediate area and used in the revegetation process.
•
The R7 billion project
is one of the largest private capital
•
projects ever
undertaken in South Africa and will generate some R1,8 billion of foreign exchange per
annum.
•
400 of the current 600
permanent employees have been recruited from the West Coast and put on a two-year training
course locally and abroad.
•
Saldanha Steel aims to
create at least 20 000 jobs through
•
outsourcing and new
business creation over the next ten years.
•
More than 9000 people
were involved during the construction phase of the programme.
Environmental
Consultants
Developer: Saldanha Steel Pty (Ltd)
Environmental Management Co-ordinator: Barend Smit, VKE Engineers
Environmental Manager: Siggi Spanig, Saldanha Steel
Environmental Impact Assessment: Keith Wiseman, CSIR
Public Participation: Crowther Campbell and Associates
Environmental Monitoring Committee (Chairman): Prof Jan Giliomee, University of
Stellenbosch
Architect: Hannes Meiring Architects
Environmental Working Committee: Dr Allan Heydorn, WWF and Prof Willem van Riet
Compilation of Environmental Management Model and Environmental Management Plan: Van Riet
& Louw Landscape Architects
Landscape architect: Willem van Riet Landscape Architects
Re-vegetation and landscape contractors: Top Turf Cape
External Environmental Auditor: Dr John Raimondo, African Environmental Solutions
Other environmental
specialists
Visual impact assessment: Cave Klapwijk & Associates
Groundwater: John Weaver, CSIR WaterTech
Geology: Dr John Rodgers, Department of Geology, UCT
Noise: Vincent Robertson & Francois Le Roux, SABS
Air pollution: Dr Nico Boegman
Waste classification and permit application: Dr Ockie Fourie, Fia Swart and
Corrie van Rensburg, ISCOR mining
Flora: Dr C Boucher, Department of Botany, University of Stellenbosch
Archaeology: Jonathan Kaplan, Agency for Cultural Resource Management
Traffic impact: VKE Engineers
Due to space constraints, only those involved with the environmental aspects of
the project are listed here. |
