http://www.engineeringnews.co.za
  SEARCH
Login
R/€ = 13.89Change: 0.04
R/$ = 12.69Change: -0.03
Au 1086.80 $/ozChange: -8.38
Pt 962.00 $/ozChange: -20.00
 
 
Note: Search is limited to the most recent 250 articles. Set date range to access earlier articles.
Where? With... When?








Start
 
End
 
 
And must exclude these words...
Close Main Search
Close Main Login
My Profile News Alerts Newsletters Logout Close Main Profile
 
Agriculture   Automotive   Chemicals   Competition Policy   Construction   Defence   Economy   Electricity   Energy   Environment   ICT   Metals   Mining   Science and Technology   Services   Trade   Transport & Logistics   Water  
What's On Press Office Tenders Suppliers Directory Research Jobs Announcements Letters Contact Us
 
 
 
RSS Feed
Article   Comments   Other News   Research   Magazine  
 
 
Jul 08, 2011

Environmental projects at Vanderbijlpark works well under way

Back
ArcelorMittal South Africa environmental GM Siegfried Spanig discusses the company's plans to spend more than R2-billion over the coming four years to ensure that all its operations are compliant with the country's increasingly stringent environmental legislation.
 
 
 
Chute|Construction|Africa|Chute|Components|Dewatering|Environment|Hydrocarbons|PROJECT|Projects|Storage|System|Testing|Waste|Water|Africa|Chute|Manufacturing|Steel|Environmental|Waste|Water|Chute
Chute|Construction|Africa|Chute|Components|Dewatering|Environment|Hydrocarbons|PROJECT|Projects|Storage|System|Testing|Waste|Water|Africa|Chute|Manufacturing|Steel|Environmental|Waste|Water|Chute
chute-anniversary|construction|africa-company|chute|components|dewatering|environment|hydrocarbons|project|projects|storage|system|testing|waste-company|water-company|africa|chute-industry-term|manufacturing|steel|environmental|waste|water|chute-product
© Reuse this



Steel producer ArcelorMittal South Africa’s rehabilitation projects at its Vanderbijlpark waste disposal facilities are well under way.

The steel giant is currently undertaking remediation projects at the former waste- water disposal dam (Dam 10), the central effluent treatment plant (CETP) sludge dams, the maturation ponds and the old steel manufacturing waste disposal site at its Vanderbijlpark works.

Mittal expects the R48-million bio- remediation of Dam 10 to be completed by October this year.

The project forms part of the company’s R2-billion drive to further improve the environmental impact of its plants across the country in the coming years.

The 75 ha dam was commissioned in 1960 as part of a number of wastewater storage and evaporation dams. Two of the dams were used for organically contaminated wastewater, while the remaining dams were used for inorganic wastewater.

Organic effluent from coke ovens at the site’s coke plant was historically pumped into Dam 10 and contaminated the underlying clay sediment.

Coke oven effluent contains significant amounts of polycyclic aromatic hydrocarbons (PAHs) along with more soluble components such as cyanide, phenols and ammonia.

Mittal environmental manager Karien Zantow explains that the insoluble PAH-containing tars settled out and built up at the bottom of the dam. Little biodegra- dation took place in the bottom sludge and the organics accumulated over the years. Thus, after extensive dewatering of the dam, tar pools appeared in some areas.

Changes in environmental policy and concern over accumulated priority pollutants resulted in the effluent-handling process being changed and the dam being decommissioned.

“Disposal of the settled sludge and contaminated soil became a priority and various methods were investigated. “Eventually 150 000 m3 of sludge and soil was identified for cleanup and on-site bioremediation was the most cost effective option,” she adds.

Use of the dam stopped in 2000 and it is currently undergoing rehabilitation using archaea microorganisms that are added to the contaminated soil to break down waste compounds.

Each species of archaea serves a specific purpose and functions optimally at varying levels of pH and temperature.

Zantow explains that the addition of high concentrations of a diverse range of archaea to a treatment system permits some species to select to the environment encountered. As the environment changes, the continuous addition of the biosystem ensures that the microorganisms continue to populate the treatment system and perform effective breakdown.

Methodology
The archaea are grown in an on-site reactor and mixed with the soil using custom-built windrowers.

Between six and seven months are required for the soil to achieve a 97% rehabilitated status.

Between 2002 and 2004, the dam was dried out, followed by remediation of 98% of the area between 2008 and 2010. The process involved excavation of the 800-mm-thick layer of tar sludge and contaminated soil that was stacked into windrows within the existing footprint and surface of the dam.

Hay and organic compost are added to the top of the piles by 20% of volume and are mixed using the self-propelled windrow machines. Simultaneously, 25 ℓ of archaea, which consists of 8% solution with 0.05% surfactant, was sprayed for each cubic metre of soil.

The application is strictly controlled by Mittal technologist Johan Hattingh.

Zantow says testing indicated that organic breakdown had been successful in the completed section and the required soil cleanup targets for all organic pol- lutants achieved.

“Testing on the windrows showed that between 88% and 99% of all pollutants were broken down,” she notes.

Chemical composition of the prepared windrows was determined by taking core samples from each side along the length of the windrows. The cores were blended and samples submitted for analysis of PAH, which is regarded as a priority pollutant by the Environmental Protec- tion Agency and known to be present in coke oven effluent.

The rehabilitation process further entails that the windrows be turned at least every two weeks. The revitalised soil is then reworked into the lower clay layer to serve as the topsoil, after which five indigenous grass species are planted. The end result is a completely self-sustaining open field.

Similar remediation of the remaining 2% of the area is currently under way with final vegetation to be completed by October this year.

“The main objective of the project was to limit possible contamination of sur- face water and ensure clean stormwater runoff from the site after remediation,” Zantow says.

Other benefits of the rehabilitation project will be the lowering of the risk of contamination seepage into the ground and reducing dust to a large extent by planting grass. The grass also serves to transform the former dam into an aesthetically pleasing area.

Zantow adds that, when rehabilitation is complete, the space will be reserved as a storage area; however, until it is needed for that purpose, it will remain an unused vegetated field.

“This flagship project will reduce the impact of a legacy facility that has been in operation for the last 50 years,” she states.

CETP Dams
The site’s old CETP sludge dams will undergo the same bioremedation procedure once Dam 10’s bioremediation has reached completion.

The remediation of the CETP sludge dams comprises different phases, with the first phase, which involved the safe disposal of inorganic sludge, having been completed at a cost of R12-million last year.

“The company excavated 650 000 m3 of inorganic sludge from these dams in August last year. The remaining material is currently being windrowed for bioremediation,” says Zantow.

Further, Mittal budgeted R11-million for the second phase, during which about 45 000 m3 of sludge will undergo organic remediation. The second phase is expected to start in October and be completed by July next year.

The third phase will entail sloping and shaping of the area and the implementation of a stormwater control system. The phase is set to start in June next year and reach completion by June 2013.

Soil stabilisation and revegetation will be done during the fourth and final phase that will run from July next year to March 2014.

Maturation Ponds
Mittal is also currently undertaking reme- diation projects at its Vanderbijlpark maturation ponds that were initially used to moderate the effluent toxicity to vegetation to enable use of the water for turf irrigation in the Kiewiets area.

The maturation ponds, which comprise three dams (Dam 1, Dam 2 and Dam 3), were decommissioned in 2008.

Remediation of the dams entails soil pH stabilisation. The process at Dam 3 started in 2009 and was completed last year.

The same soil stabilisation method, which has been determined and implemented by remediation specialist Viljoen & Associates at Dam 3, will also be implemented at Dams 1 and 2.

Viljoen & Associates owner Chris Viljoen explains that the soil is characterised and polygons of contamination are drawn on areas with similar contamination levels. Specific and differential application and treatment rates are then determined for each polygon area.

This means that the entire surface is not treated or stabilised as one homo- genous soil body, but that targeted and specific treatment is applied depending on the soil quality.

“The success of the soil remediation strategy in conjunction with pH stabilisation is embedded in the increase in buffer capacity through an increase in the percentage of amorphous carbon per mass and/or volume soil content. “Owing to the adsorptive characteristics of carbon, a significant dilution effect is created in the double layer solution around the colloidal soil particles. “Sufficient gypsum, lime and carbon are also added in specific ratios to ensure the sodium adsorption ratio is corrected,” Viljoen says.

At Dam 2, windrows have been packed and remediation is expected to start in October this year and be completed in December next year.

Dam 1 is currently undergoing on-site water and sludge remediation, which will be completed in 2012.

The total remediation process of the maturation ponds is expected to be complete by the end of 2015. To date, R6.5-million of the R30-million allocated for the project has been spent.

Waste Disposal Site
Further, remediation of the Vanderbijlpark works’ old 170 ha waste disposal site is in progress.

Zantow says about 40-million cubic metres of waste, which consists mainly of steelmaking slag, dust and filter cake, has been disposed of at the site since its inception in the early 1960s.

Disposal on the old waste site was terminated in December 2010 as dictated by water use licence requirements that prohibit disposal beyond the site reaching 40 m in height.

Remediation of the site is done in three phases, during which the area is divided into three sections that will each undergo subsequent remediation through sloping, shaping and soil capping.

Stormwater drainage canals will also be constructed to divert clean runoff into the main stormwater chute that joins the clean stormwater system.

During capping, the area surface is covered with a 1.5 mm flexible high- density polyethylene liner and then covered by a 500-mm-thick layer of clean com- pacted soil, followed by a 200-mm-thick clean topsoil layer.

The side slopes are also covered with three 150-mm-thick compacted layers of clean clay.

Fertilisers are then added to the topsoil and hydroseeding is done for the establishment of indigenous vegetation.
Phase one cost R30-million and ran from September 2009 to October 2010.

Sloping and shaping of the soil for the similar, but much larger, second phase began in January this year, with capping to start in July. The total environmental provision budget for phase two is R47-million.

Zantow says that packing of the liners for the second phase of the project started in June.

“According to our project programme, the second phase is to be completed in September next year,” she adds.

The third and final phase will begin in 2013 and will be completed by 2015 at the latest.

The total budget for the waste site remediation project amounts to about R100-million.

New Waste Disposal Site
Construction of Mittal’s new waste disposal facility started in January last year.

Further, construction of the leachate dam, which is designed to store toxic liquids, started in April last year. The R23-million project was completed in December last year, with operation starting in January this year.

Edited by: Chanel de Bruyn
Creamer Media Senior Deputy Editor Online
© Reuse this Comment Guidelines (150 word limit)
 
 
 
 
 
 
 
 
Other Environment News
Article contains comments
More than 10% of South Africans “live in extreme poverty” on less than R16 a day‚ according to an Oxfam report to be released on Friday. “South Africa faces the triple challenge of poverty‚ inequality and unemployment‚” the Oxfam report said.
ETERNITY PROJECT The Eternity Project is the world’s first cogeneration power plant that uses an organic rankine cycle
The R175-million Eternity Project, an initiative that uses waste heat from mining processes, has reached full commissioning at platinum group metals miner Anglo American Platinum’s (Amplats’) Rustenburg-based Waterval smelter.
SANITATION PRODUCTS GreenWorx sells its biological sanitation products for use in urban systems
Bacteria of the Bacillus subtilis species secrete four enzymes that break down organic material to enable the bacteria to digest it, and microbiological cleaning company Green Worx Cleaning Solutions uses their natural functions to clean organic waste in sanitation...
Article contains comments
More
 
 
Latest News
Updated 5 hours ago The Department of Labour (DoL) will on Tuesday start hosting a series of national public hearings to review the farming and forestry sectors’ minimum wages and conditions of employment as prescribed in Sectoral Determination (SD) 13. The department explained in a...
Updated 6 hours ago The Independent Communications Authority of South Africa (Icasa) on Monday announced that it was “eager” to “reinitiate” the licensing process for the assignment of the high-demand spectrum. Icasa, which was responsible for the allocation of spectrum to broadcasting...
Updated 6 hours ago Lien Visage, a community development worker at Donkerbos, near Rietfontein, has won the Witzenberg regional of the 2015 Farmworker of the Year competition, an initiative celebrating excellence in the Western Cape’s agricultural sector. “South Africa has earned a...
More
 
 
Recent Research Reports
Real Economy Year Book 2015 (PDF Report)
There are very few beacons of hope on South Africa’s economic horizon. Economic growth is weak, unemployment is rising, electricity supply is insufficient to meet demand and/or spur growth, with poor prospects for many of the commodities mined and exported. However,...
Real Economy Insight: Automotive 2015 (PDF Report)
Creamer Media’s Real Economy Year Book comprises separate reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, gold, iron-ore and platinum sectors.
Real Economy Insight: Water 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Construction 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Electricity 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Road and Rail 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
 
 
 
 
 
This Week's Magazine
Daimler truck test engineer Dirk Stranz pushes one button, and then retracts his hands from the steering wheel of the Mercedes-Benz Future Truck 2025. “And now the truck is driving itself.”
The statutory body responsible for skills development and support in the banking sector, BANKSETA, was investing R68-million in the capacity building project of the University of Venda (UniVen), announced Bankseta company secretary Caroline King at a media event in...
LIONEL MOYAL Cloud services providers must compete against other cloud services providers for business by providing up-to-date systems and services
Legacy information technology (IT) systems are becoming increasingly obsolete because of the maturity, efficiencies and cost effectiveness of cloud-based IT services, says information and communication technology major T-Systems subsidiary Intervate head Lionel...
ARMANDÉ KRUGER Balancing the collection and processing of data must be aligned to strategy
Many complementary services enable companies to derive broad value from data inside and outside them. The complexity of data management means that companies’ strategies determine the various data systems and functions they will use, says PBT Group regional sales...
The South African Civil Aviation Authority (SACAA) has announced that it had awarded the country’s first remotely piloted aircraft systems (RPAS) pilot’s licence. It was issued on Friday, July 10, to SACAA employee and qualified commercial pilot Nicole Swart,...
 
 
 
 
 
 
 
 
 
Alert Close
Embed Code Close
content
Research Reports Close
Research Reports are a product of the
Research Channel Africa. Reports can be bought individually or you can gain full access to all reports as part of a Research Channel Africa subscription.
Find Out More Buy Report
 
 
Close
Engineering News
Completely Re-Engineered
Experience it now. Click here
*website to launch in a few weeks
Subscribe Now for $96 Close
Subscribe Now for $96