Jun, 12 2009
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(Rialto, California) — Fifty miles east of Los Angeles, a small and inconspicuous facility is using something most of us would rather not think about — household sewage — to create a resource we can’t live without — fuel.
EnerTech Environmental, an Atlanta startup, on Thursday unveiled the United States’ first commercial biosolids-to-energy facility in California’s Inland Empire. “Biosolids” is the nice term for processed sewage sludge.
The sludge is 80 percent water when it arrives at EnerTech’s plant, where it is turned into fuel simply by removing most of that liquid.
The product customers buy is 95 percent solid and interchangeable with coal, according to Chief Executive Kevin Bolin, whose grandfather invented the company’s patented “SlurryCarb” technology.
Enertech’s “E-fuel” is already being used as a replacement for coal at two Southern California cement kilns, though it currently accounts for only about 10 percent of their needs.
“With respect to the cement industry, we can’t make enough,” Bolin said at the plant’s ceremonial opening.
Biosolids are a renewable resource and do not add any net carbon dioxide to the atmosphere, Bolin said.
“The CO2 is already in the cycle,” he said. The pungent smell that permeates the area comes from a nearby wastewater treatment plant, Bolin said.
EnerTech’s plant started production earlier this year and is operating at about 60 percent capacity. At full capacity, it will be able to take in 700 tons of biosolids to produce 170 tons of fuel a day.
That puts the facility on par with a roughly 7-megawatt power plant, Bolin said.
Cement kilns are ideal customers for EnerTech’s product because not only does it provide a renewable replacement for coal, the non-combustible portion of E-fuel is mixed into the cement itself, Bolin said.
EnerTech receives sewage sludge from five Southern California municipalities, including Orange County, Los Angeles and San Bernardino. Because it provides a recycling service, EnerTech is paid by the cities and sanitation districts for managing their sewage sludge.
As a result, EnerTech’s final product is cheaper to its customers than buying coal, Bolin said.
“It’s able to be cheaper than coal because the primary focus is the management of biosolids,” Bolin said.
EnerTech, which counts Citigroup private equity unit Metalmark Capital and the Masdar Clean Tech Fund among its investors, expects to turn a profit next year, Bolin said.
It is expanding. The company has partnered with Mitsubishi Kakoki Kaisha Ltd on a demonstration plant in Japan, and EnerTech is looking at other opportunities in the United States and the UK, Bolin said.
EnerTech plans to expand the Rialto plant to make fuel for Rentech Inc, a Los Angeles-based synthetic fuels maker that plans to use the biosolids to make transportation fuels. It is also hopes to develop a plant in the New York City area.
EnerTech’s SlurryCarb process isn’t limited to human sewage. It can also treat animal manure, lumber and paper wastes and agricultural wastes.
By: Nichola Groom
Even though the global economy is showing no signs of a revival, the global green building materials market expects a boom in the next few years.
The market for green building materials is expected to grow to $571 billion by 2013, a staggering climb of $116 billion increase from the market’s value in 2008.
A 48 page report by NextGen provides statistics regarding the growth in the market. The report envisages that the market will grow at a five percent compound annual growth rate. The report is targeted to provide information to manufacturers, developers, contractors, green building and building product standards organizations, home improvement retailers and venture capital firms.
The report looks into products such as cement, engineered wood, and insulation products.
The report analyses the benefits of green building materials as opposed to standard building materials. Green building materials have a favorable impact on energy consumption, water use, waste disposal and carbon footprint. The report also provides an insight into government and legislative developments, sustainable development and how the comparative development of green building materials market as compared to the overall building materials market.
The report also provides detailed information on standards for green building and which organizations certify green building and green building products.
NextGen’s research director, Larry Fisher, commented that the construction industry has a noteworthy impact on the environment, and therefore the importance of green building materials.
He added that the construction industry has a significant bearing on United State’s energy consumption and on a considerable portion of the country’s carbon dioxide emissions.
The report prophesizes that commercial office buildings will emerge as the largest non-residential target sector for green building products over the next few years. The report also predicts that new residential building and home improvement sectors are emerging markets for green building products manufacturers.
‘New’ CONCRETE Hi-Fi Loudspeaker System
“My first experience of concrete as a loudspeaker material was in the late sixties when a relative used a large diameter soil pipe to house a base driver unit – I was hooked!”
(WEST YORKSHIRE, UK) — The purpose of a Hi-Fi loudspeaker system is to present the sound from the individual drive units with optimum performance. This can only be achieved if there is sufficient stiffness in the cabinet to cut out any coloration (distortion in sound). The conventional solution has been to use wood-based composite or more recently, the introduction of plastic (polymer) composites. Many designs look good but do not deliver high quality sound.
My speaker cabinet is “inert”. Its distortion level is almost zero even at high volumes. Therefore, you only hear the recorded sound in your room.
So why concrete?
• Concrete has a very high mass / density which contributes to its high damping qualities;
• It is much stiffer than conventional loudspeaker construction materials;
• Its density stabilises the speaker system allowing the drive units to function at their maximum specification;
• It is moulded using an homogenous construction design ensuring a thoroughly rigid cabinet – (conventional construction methods have an inherent weakness in the joints);
• The strength of concrete increases over time, giving you a product that improves with age;
• My latest designs have a white ‘marble-like’ finish.
Gavin Alexander on his inspiration behind Concrete Speakers
After studying material technology at London University, I built my first set of concrete speaker cabinets using KEF drive units. I was impressed with the purity and depth of sound. I then furthered my knowledge and understanding of concrete as a material at the Cement and Concrete Association in Slough.
In 1982, I built the concrete speakers I use to this day. Though many of my other hi-fi components have been upgraded, my speakers remain constant and the source of many hours of listening pleasure.
My latest design has been evolving for 3 years. I have carefully matched individual drive and crossover units will be used to compliment the qualities of the cabinet material. Ingredients for the concrete mix have been carefully chosen to enhance the visual as well sound quality.
“The finished product has the appearance of white marble”.
These exclusive speakers will be made to order.
For further information please visit http://www.concretespeakers.co.uk
The first batch of bricks have rolled off the production line at Hanson UK’s new £50 million brick factory at Measham in Leicestershire.
The plant is the largest ‘soft-mud’ brick plant in Europe, and uses locally sourced recycled raw materials and the latest low energy, low waste technology to make bricks with the lowest embodied CO2 available.
The factory can produce 30,000 bricks an hour and uses just 28 staff to do so.
Hanson Building Products managing director David Szymanski and Travis Perkins chief operating officer, John Carter saw the first load of Atherstone Red off the production line and onto the delivery vehicles.
Carter said: “I have always appreciated the country’s affection for bricks and it is great to see that this tradition can continue in the 21st century with Measham producing bricks for low carbon construction.”
(UK) — BLACKPOOL International Airport is benefiting from significant cost, waste and energy savings after having its main runway resurfaced using the Colas Repave recycling process.
Colas were awarded the contract after submitting a more cost-effective and sustainable alternative to the resurfacing designs originally proposed, which had been based on conventional plane-out and replacement of Marshall asphalt to a depth of 50mm.
‘Repave reduced the requirement for new material by 38% and, therefore, brought costs down significantly,’ explained Colas’ airfields business manager, Carl Ferguson. ‘It eliminated over 600 tonnes of waste and reduced energy consumption by 29%. Use of Repave also eliminated about 100 lorry movements and cut the quantity of CO2 generated by the works by 28%.’
Colas’ alternative design involved planing off the top 30mm of Marshall asphalt across the runway’s 16m wide central strip and then applying the Repave machine to reheat and rejuvenate the exposed asphalt down to a depth of 25mm.
A new 30mm layer of Marshall asphalt was then laid on to the hot material to create a homogenous asphaltic bond between the recycled and new asphalt.
Work at night was restricted to keep the total ungrooved runway length to a maximum of 99m, while associated work on ground lighting and adjacent taxiways was carried out on alternate nights to suit the need for a 48h period between resurfacing and surface grooving operations.
Repave is particularly suitable for the rehabilitation of airfield pavements and is said to provide significant whole-life-cost benefits. The hot weld results in a monolithic asphalt layer, allowing a thinner layer of new material to be laid, and is also superior to a tack coat in terms of long-term performance.
Repave is also said to aid re-profiling, as it takes out irregularities in the surface and saves time by eliminating the need for the pre-patching of cracked areas.
Tel: (0121) 561 5561
Fax: (0121) 561 4364
SouthLake Texas) — As the economic stimulus packages begin to roll out, especially those related to infrastructure spending, many concrete product producers will begin looking for ways to tap into these projects and gain a substantial high-ground advantage in the procurement of these funds.
Two key trends are emerging that will separate the innovators from the followers and establish a new level of leadership within the industry: the green building products movement, and the use of recycled materials in the production of building materials.
The ever increasing adoption of LEED and other nationally recognized programs geared toward the use of innovative design and construction materials is gaining significant momentum within the A&E design community. Both public and private sector construction projects, and the design teams attached to them; are now seeking to take better care of our environment and limit the negative effects of future development.
For manufacturers of all kinds, this will provide an opportunity to find markets that were heretofore inaccessible or at the very least, difficult to penetrate. For producers of concrete products the opportunities are considerable given the current focus on the rebuilding of our roads and bridges, if they can properly position themselves.
Key product solutions like storm water management, control and limitation of solid surface pavement, and the incorporation of recycled materials in the manufacture of all concrete products have shown extensive traction and acceptance. The use of permeable paver systems with the ability to contain large volumes of storm water on-site and within the system are being researched and specified in an ever expanding array of project types.
In addition, some concrete product manufacturers are now replacing up to 20% of some natural aggregates with processed post consumer recycled materials. This trend will generate benefits on several levels from the extension of natural resources, a reduction in waste build-up, and the increased development of alternative products that can be incorporated into these applications.
A number of concrete producers are already incorporating crushed waste concrete and cement replacements like fly ash and slag cement into their mixes to differentiate themselves as providing a green product. While these actions are admirable and cost effective, the true potential will be realized with the incorporation of post consumer waste products and the continued development of new and innovative products.
Mark J Muratore, President
Concrete Results, Inc.
During the last century, the Earth’s average surface temperature rose by around 0.6°C. Evidence is getting stronger that most of the global warming that has occurred over the last 50 years is attributable to human activities, especially the rapid consumption of the fossil fuels. The levels of greenhouse gases including carbon dioxide have reached unmatched levels. This has lead to the governments and industries thinking seriously about alternative sources of energy. This need was further affirmed by the 1973 oil embargo and the ever increasing oil prices since then. These issues along with declining availability of the fossil fuels has led to the fast development of renewable energy resources like solar energy, wind energy, etc.
Renewable energy is defined as the energy derived from resources that are regenerative or for all practical purposes can not be depleted. Renewable energy offers tremendous benefits for meeting global energy needs. Building on a foundation of hydropower, biomass combustion, and geothermal power pioneered during the industrial revolution, new forms of renewable energy began to be developed and commercialized, including solar, wind, and several forms of advanced bioenergy. Today, the global renewable power capacity has almost reached 200 GW and by 2030, the overall demand for energy resources is expected to almost double the current levels. And it is almost certain that renewables will play a major role in fulfilling most of that demand. These technologies are the fastest growing energy technologies – particularly wind and solar – and are cost competitive in a variety of grid, off-grid, and remote applications worldwide. They utilize locally available resources, off setting the need for costly fuel imports, are environmentally beneficial, without the harmful emissions of conventional energies, provide diversification to a country’s energy mix and create local job and income opportunities.
Nonetheless despite their advantages, the bulk of renewable energy development to date has occurred in industrialized countries, with the limited exception of a few emerging economies like China and India. The countries most in need of the positive attributes of these technologies are not yet beneficiaries. This is due in large part to a number of barriers that hinder renewable energy advancement. Most notably, renewable energy continues to be comparatively expensive for a variety of developing country needs. Further, many of these countries have not yet put in place the policy and regulatory frameworks needed to induce investment in renewable energy, or eliminated subsidies for conventional fuels that make it difficult for the technologies to compete. Moreover, many developing countries have imperfect capital markets and insufficient access to affordable financing for developers and consumers, as well as inadequate institutional capacity to support the technologies.
Global Renewable Energy Market reports focuses on the current developments in the sector and its potential worldwide. History, current status and future for each of the renewable source – hydropower, solar, wind, biomass and geothermal – is discussed. Further, assessment of the major markets has been done along with policies around the world and profiles of key companies in the industry. Also, report presents a detailed cost analysis of various renewable resources.
The Colorado Department of Transportation (CDOT) has used Reclaimed Asphalt Pavement (RAP) as a base on many projects as a reconstruction strategy. CDOT’s specifications allow RAP to be substituted for unbound aggregate base course (ABC).
The laboratory tested properties of reclaimed asphalt pavement are similar to CDOT’s aggregate base course specifications.
* RAP has pavement design properties similar to aggregate base course;
* A suggested gradation specification band is presented for RAP;
* RAP requirements for PI and LL may be the same as ABC Class 6, PI not to exceed six and LL not greater than 30;
* The stiffness strength properties obtained from laboratory testing shows that RAP has stiffness strength above an unbound ABC Class 6;
* The permeability of RAP showed a slight increase over an unbound ABC Class 6.
Greystone Inc.) — When fine material screws fail to remove enough moisture from their material, many sand operations decide to introduce a dewatering screen into their material flow.
The producers who own them already know that dewatering screens typically require little maintenance. While some dewatering screens resemble traditional sizing screens that use eccentric shafts to induce their shaking motion, the majority of dewatering screens use high-frequency vibrators and have few moving parts. The screens are designed for an operator to simply flip a switch and run them, day in and day out. However, even low-maintenance machines still require some care and the minimal maintenance needed is essential to their successful operation. In addition, operator error can affect both capacity and drying capability on these simple screens.
Opportunity For Error
With either dewatering screen type, the theory behind water removal is the same; as the wet sand feed creates a deep material bed on the screen deck, the combined material weight and motion of the screen’s throw work to squeeze water through tiny apertures in the screen media. At the same time, the throw moves the material down the screen’s length. The desired result is that sand coming off the end of the screen should have a moisture content of 10 percent or less.
Dewatered sand coming off the end of the screen should have a moisture content of 10 percent or less.
Ideally, the dewatering screen’s feed should create a deep material bed on the screen deck.
The combined material weight and motion of the screen’s throw work to squeeze water through
tiny apertures in the screen media.
The most common complaints noted among dewatering screen operators—those of wet material and decreased capacity—are usually the result of not feeding enough material. If the screen cannot form a deep bed of sand, it will not be able to retain the product on the screen to remove the moisture and will also have trouble effectively moving the sand down the length of the screen. It is the vertical/diagonal vibrating motion of the screen, along with the inertia of the sand, that work to squeeze the water through openings in the screen media. The thinner the bed depth, the lower the inertia, resulting in lost and wet material—ultimately defeating the purpose of a dewatering screen.
If the feed does not create a proper bed depth, the result will be wet material and decreased capacity.
The thinner the bed depth, the lower the inertia, resulting in lost and wet material—ultimately defeating
the purpose of a dewatering screen.
Another common mistake among producers who are not familiar with dewatering screens is purchasing a unit based on desired plant capacity, rather than current production capability. In order for the screen to handle the feed correctly and create the ideal bed depth, the producer must look realistically at the plant’s current production numbers. A high-capacity dewatering screen that is too large for the feed will not effectively dewater or move the material.
Most dewatering screens allow for adjustment of the throw and the screen’s angle of incline—from horizontal to about 5 degrees uphill or downhill. Both adjustments can affect the capacity of the screen and its drying capability. If an operator adjusts the screen for a steeper uphill angle with less throw, it will require that less tonnage be introduced to the screen. The opposite is also true, with a horizontal screen or downhill angle with a harder throw allowing higher feed tonnage. Producers should initially work with the manufacturer to adjust the screen for the best angle and throw to meet their desired results. Later, if material properties change or production increases or decreases, the manufacturer and/or the equipment dealer can help determine the best settings and recalibrate the unit to operate under new parameters.
With sizing screens, the purpose of the screen media is for the material to go through the openings. With a dewatering screen, the goal is to retain the material on the deck, allowing only the water to filter through. Dewatering screen media does not wear as fast as media used on sizing screens, but when it does wear, it should be replaced immediately. Although dewatering urethane typically tends to wear at the surface of the screen, instead of the openings, any wear that does appear at the openings will allow salable material to fall through the screen along with the water. In addition, because the openings are very fine, they can punch through or tear easily if stepped on or if tools are dropped on the screen panels. In order to ensure retained product, the media should be examined regularly for signs of wear or holes, and worn or torn panels should be replaced.
Vibrating Motors: For dewatering screens that use high-frequency vibrating motors, operators need to know that these motors run fast, from 900 rpm to 1,800 rpm, depending on the screen and motor. Additionally, their linear throw can equal up to 6 g (six times the force of gravity, which means that one ton of sand is equal to six tons—or 12,000 lbs—of force), so they generate a lot of force driving up and down. If these motors and their mounting apparatus are not kept properly maintained, they can destroy themselves rapidly and create safety hazards.
Because of their great speed and linear throw, vibrating motors generate a lot of force driving up and down.
These motors and their mounting apparatus must be kept properly maintained,
or they can destroy themselves rapidly and create safety hazards.
As a standard step in safety and operating the machine efficiently, producers need to maintain the bearings on the motors, following manufacturer-recommended intervals. The motor’s manufacturer provides greasing schedules for the bearings, as well as startup procedures, which should be included in the screen manufacturer’s operation and maintenance manual.
Ensure that bolts are tightened to the correct specifications. If the bolts or the frame are cracked, repair them immediately. Most manufacturers will recommend checking the torque on the bolts prior to initial startup when the unit is first installed, followed by regular inspections at least twice a year. Inspect the motor mount regularly; if cracks are found, repair them immediately.
Eccentric Drives: For eccentric shaft dewatering screens, the maintenance of the motors and bearings is similar to that of traditional sizing screens. Manufacturers should provide schedules for maintenance, but most recommend checking the belt torque on the wheel case approximately four times a year. It is a good idea to check the drive belt and sheaves daily, as well as for leakage from the drive shaft seal. The pillow block bearings should be greased every couple of weeks or according to recommended intervals. Producers should also check the wheel case oil for contamination after 250 hours of operation and change it according to manufacturer specifications.
While dewatering screens are not that maintenance intensive, understanding how they perform and what maintenance is important will guarantee long-term success.
GreyStone Dewatering Screens
GreyStone, Inc. offers three models of Dewatering Screens—the DS-488 (4-ft x 8-ft), DS-6010 (5-ft x 10-ft) and DS-7212 (6-ft x 12-ft)—to handle a variety of capacities and efficiently dewater up to 350 tons per hour. Many concrete and masonry sands typically retain from 18 to 24 percent moisture, which requires drying time in the pile. At process end, the GreyStone Dewatering Screen cuts that moisture down to as low as 10 percent or less—providing salable material in less than a day.
By: John Bennington
Vice President & General Manager
Web site: http://www.greystoneinc.com
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