Mar 30, 2012
Anaerobic digestion in wastewater treatmentBack
AD|Talbot|Talbot Laboratories|Africa|South Africa|Anaerobic Digestion Technology|Chemical Oxygen|Digester Treatment Systems|Large-scale Pond Systems|Upstream Effluent Management|Anaerobic Digestion Technology|Biofilter Technology|Process Control|Reverse Osmosis Technology|UASB Technology
© Reuse this
Water and wastewater management company Talbot & Talbot continue to successfully build and operate Upflow Anaerobic Sludge Blanket (UASB) digester treatment systems for companies throughout South Africa and Africa, across a range of industrial sectors.
“It is widely accepted that while anaerobic digestion is a proven, effective and highly efficient treatment system, upsets in performance remain common. A correctly run digester will efficiently convert up to 95% of organic material into a low-odour stabilised slurry and produce a renewable resource in the form of biogas that can be flared or used on site.
“This eliminates the need for additional solid handling and large-scale pond systems and limits reliance on nonrenewable fuels. Digester disturbances, however, continue to represent a significant risk limiting the widespread adoption of this technology,” the company highlights.
Under the Department of Water Affairs’ (DWA’s) water use licence conditions, the discharge of untreated effluent into water bodies, following reactor failure, can attract noncompliance penalties of millions of rands and, under special limit conditions, the forceful shutdown of operations for lengthy reseed periods of the digester.
Consequently, new applications are often over-engineered, under-loaded and relatively expensive.
“Despite decades of research into anaerobic digestion technology, a fundamental understanding of upstream effluent management, system sensitivity and basic process control continue to be highlighted as ongoing concerns, severely limiting the reputation and diversification of this technology,” notes Talbot & Talbot.
Digesters vary in capacity from 1 Ml/d to 5 Ml/d, treating between 1 t and 25 t of chemical oxygen demand a day, under general limit and special limit licence conditions.
The company believes that a high-performance anaerobic digester (AD) treatment system is attributed to a fully integrated approach, which begins with a systematic site water management plan and process optimisation within a client’s core business.
“Upstream focus is essential in preventing discrepancies in effluent data, which results in incorrectly designed, overloaded and poorly performing digesters; in segregating and correctly disposing of solid waste streams; and in ensuring potentially harmful contaminants are identified and isolated from the effluent system,” it states.
Plant design and construction is offered on a full turnkey basis, in addition to a full aftercare service through Talbot Operations, a business division of Talbot & Talbot.
This includes operator training, performance review and compliance monitoring on a support basis, as well as a dedicated team of competent operations and maintenance personnel on a fully outsourced basis.
“In addition, effluent sampling schedules are implemented through Talbot Laboratories to rapidly identify changes in effluent quality and monitor final discharge compliance. This guarantees the long-term treatment potential of UASB technology and a full commitment to the industry, which cannot be achieved on a build-only basis,” the company says.
A well-managed, high-performance AD system provides clients with the opportunity to recover water and energy resources from their effluent.
Secondary treatment systems in the form of activated sludge, sequential batch reactor and biofilter technology provide good-quality effluent treatment options, while water reclamation can be incorporated by ultrafiltration and reverse osmosis technology.
More recently, Talbot & Talbot have successfully designed and commissioned biogas recovery systems that capture the by-product of digestion, methane, as a renewable, carbon dioxide-energy source.
A 25 t digester with a biogas production of 6 500 Nm³/d can typically produce 52 t/d of steam, which supplements nonrenewable energy use by up to 15%.
“The realised value of a biogas recovery project (BRP) can be directly comparable to the cost of the fuel it replaces, the logistical cost of supplying fuel to remote locations and the availability of electricity throughout Africa.
Despite these benefits, Talbot & Talbot state that the real value of BRPs is the renewed interest in AD technology, a deeper understanding of good effluent handling practises and an ongoing commitment to ensuring anaerobic digesters reach their full treatment potential.
Edited by: Chanel de Bruyn© Reuse this Comment Guidelines
Other Environment News
Article contains comments
Recent Research Reports
Steel 2014: A review of South Africa's steel sector (PDF Report)
Creamer Media’s Steel 2014 report provides an overview of the global steel industry and particularly of South Africa’s steel sector over the past year, including details of production and consumption, as well as the country's primary carbon steel and stainless...
Projects in Progress 2014 - First Edition (PDF Report)
This publication contains insight into progress at the delayed Medupi and Kusile coal-fired projects, in Mpumalanga and Limpopo respectively, as well as at the Ingula pumped-storage scheme, which is under construction on the border between the Free State and...
Automotive 2014: A review of South Africa's automotive sector (PDF Report)
The report provides insight into the business environment, the key participants in the sector, local construction demand, geographic diversification, competition within the sector, corporate activity, skills, safety, environmental considerations and the challenges...
Construction 2014: A review of South Africa's construction sector (PDF Report)
Construction data released during 2013 hints at a halt to the decline in the industry during the last few years, with some commentators averring that the industry could be poised for recovery. However, others have urged caution, noting that the prospects for a...
Electricity 2014: A Review of South Africa's Electricity Sector (PDF Report)
This report provides an overview of the state of electricity generation and transmission in South Africa and examines electricity planning, investment in generation capacity, electricity tariffs, the role of independent power producers and demand-focused initiatives,...
Defence 2013: A review of South Africa's defence industry (PDF Report)
Creamer Media’s 2013 Defence Report examines South Africa’s defence industry, with particular focus on the key players in the sector, the innovations that have come out of the defence sector, local and export demand, South Africa’s controversial...
This Week's Magazine
The Electronic Systems Laboratory (ESL) of the Department of Electrical and Electronic Engineering at Stellenbosch University is strongly reaffirming its position as one of South Africa’s leading centres for satellite technology and expertise. It is currently...
The world’s lowest-cost diesel-electric locomotive is not made in China, but in Pretoria, at RRL Grindrod Locomotives’ newly upgraded 30 000 m2 plant. The company’s locomotive pricing is “more competitive than any other original-equipment manufacturer (OEM)...
The South African Defence Review 2012, released to the public at the end of last month (despite the year given in its title) recommends the creation of the post of Chief Defence Scientist. This official would be responsible for the management of defence technology...
AltX-listed engineering technology company Ansys has been awarded an R188-million contract by Transnet to supply integrated dashboard display systems to the freight rail utility’s locomotives. Black-owned and controlled Ansys developed the bespoke integrated system...
South Africa’s sole nuclear power station Koeberg, which is located in the Western Cape, breached a major operations milestone on April 4, which marked the thirtieth anniversary of Unit 1 having been connected to the grid. Eskom, which operates the two-unit plant,...