Greenhouse Solar Dryer has ventured into a new material that requires drying: wastewater sludge. Solar dryer is commonly used to dry agricultural products such as vegetables, fruits and herbs. However, it is not limited to only drying products for human consumption as the dryer is also able to dry post-human consumption products such as sludge.
On an annual basis, 100,000 tonnes of wastewater sludge is generated from a population as big as Malaysia. This by-product from sewage treatment plants is often disposed to landfill or in some cases, applied at agricultural crop farm as a soil conditioner.
Both the management of sludge – landfill or application at agricultural land – are challenged by high operational cost, partly contributed by the transportation cost.
The thick, greyish colour mud-like sludge contains about 70% of water. If water content is removed, transporting a truck-load of dried sludge is estimated to be equivalent to transporting three truck-load of wet sludge. In addition to that, removal of sludge’s water content also opens up opportunity to turn dried sludge into another resource – biofuel.
Benefit of Dried Sludge
In Spain, a cement factory uses dried sewage sludge as a replacement of the non-renewable coal that has been used as a fuel in cement kilns. In essence, every one ton of sewage sludge used as fuel, can avoid 0.48 tons of carbon dioxide emissions from fossil fuels.
In Malaysia, the national sewage treatment company called Indah Water Konsortium has worked with Rubber Research Institute of Malaysia to experiment on the use of the bio-rich sludge as fertilizer.
“It was found that the rubber trees grew at a faster rate and larger in size after applying the sludge. Quality of latex produced was also maintained after the application”, said the sewage company’s chief executive director.
However, all these are not viable if the sewage sludge remains wet. Sludge drying has become a crucial step in order for sludge to be recirculated back into the economy as resources. However, the current drying process which uses directing heating is a problem as it requires lots of fuel and contributes to carbon emissions.
This is why solar dryer has become the up and coming sustainable solution.
The Sun is our Option
Drying and handling of wastewater sludge have been ever challenging for most companies or national consortiums due to some of the challenges below:
- Bad odour
- Hygiene for people to handle sludge
- High electricity cost for drying
- Poor dried sludge quality
The enclosed greenhouse structure has made drying efficient and cost-effective for many owners. The high efficiency of the dryer is achieved through the use of double-glazed glass as the greenhouse’s facade.
With argon gas filled in between the two-layered glass, the double-glazed glass has the ability to capture or insulate heat energy within the glass greenhouse for long hours. Hence, drying of sludge can continue at night or cloudy days.
In addition to that, the greenhouse can be retrofitted with mechanical system that helps to spread the sludge and perform continuous turning to ensure sludge is thoroughly dried. The system can be controlled remotely so that no workers are required to enter the piping hot greenhouse.
The greenhouse can also be custom-made according to the size and capacity required depending on the ultimate drying purpose. With the optimum system in the glass greenhouse, you do not have to worry if the sludge will be completely burnout.
In a Nutshell
The installation of solar dryer is part of Greenhouse Solar Dryer’s sustainability approach, with which the company aims to provide a practical solution that can alleviate the use of electricity for drying and at the same time, help companies to overcome drying challenges at the lowest operational cost possible. Electricity is probably used only to operate the mechanised system; the rest of the drying will be done by the Sun.
If we are the one that you have been looking for, please contact us and we would be happy to provide free consultation to you. All at our cost 🙂