Director of the IAST, Professor Dr. Suresh Narine, sought to shed some light on some of the recycling procedures and activities being undertaken by the institute, during a tour of the facility with Clean and Green Guyana/ Guyenterprise.
He noted that the rice and food commodities industries generate a significant amount of currently unused by-products, which the IAST has found useful in the manufacturing of value added food and feed products. Such materials are being used to make various noodles, cereals and risotto- which is made from broken rice. These will be produced on a commercial scale, while other local materials are being combined to make nutritionally targeted aquaculture feed.
Since 2006, the institute has been processing waste frying oils into bio-diesel. Dr. Narine explained that, “Prior to our process, waste oil would end up in the drains, leading to clogging due to precipitation and foaming and also leading to increased biological oxygen demand, which occurs when materials are present that bacteria can consume in the drains: the bacteria proliferates and when they do that, the bacteria also consume increased amounts of oxygen, which decreases the amount of oxygen available to other aquatic organisms – the results are that the other organisms die and the drains begin to smell”.
He noted that the waste material that would normally end up in the drains now goes through a process of filtration, then it is heated and chemically processed into fuel that meets and exceeds American and German standard requirements for biodiesel. This recycling process allows the institute to save up to GYD$35M in diesel annually. However, this commodity is not being produced on a commercial scale, due to the limited amount of the waste that is produced in Guyana. The institute did however construct a commercial biodiesel plant in Wauna, Region One, to process palm oil into Biodiesel.
Guyana is the first Caribbean country to commercially produce biodiesel, as a result of the institute’s capacity.
Glycerol, a byproduct of the biodiesel process, is also recycled when it is combined with sawdust and used to fuel the boiler used in the process, instead of wood. The purified glycerol is also used in another of the institute’s projects, to produce liquid soaps and hand sanitizers.
High-density polyethylene, low-density polyethylene and polypropylene (specific types of plastic) are also recycled and transformed into roof tiles by combination with up to 50 percent waste from the sawmilling (sawdust), sugarcane (bagasse), and rice milling (rice husks) industries. The tiles are a high-value product which is significantly cheaper to manufacture than asphalt shingles and other high-value roof construction materials. The institute is currently seeking to commercialize the process, which includes extrusion and injecting molding.
“We don’t utilize PET (Polyethylene terephthalate) because its melting temperature is very high and it’s hygroscopic, meaning that it absorbs water so when you heat it up in an injection molder, because its melting temperature is higher than the temperature at which water boils into steam, the absorbed water becomes steam…which can be really problematic and unsafe”, Dr. Narine pointed out.
While this process can also generate other artifacts, roof tiles were chosen to satisfy the current boom in Guyana’s construction industry.
The IAST is also undertaking a project to combine animal waste with antelope grass (which clogs our waterways) to produce biogas to provide power for street lamps. The institute already has an operational bio-reactor which currently powers biogas-fuelled lamps in its own compound.
However, it is currently in discussion with the University of Guyana (UG) to construct a large biogas reactor, to power all of the campus’ street lights, “because they spend about GYD$1M a month to power all their street lights and our solution would also allow them to effectively deal with their waste issues”, the Director noted.
A rubber recycling plant is also operated at the institution, which produces rubberized asphalt cement. “Tyres are debeaded, shredded and then granulated…the metals and nylons are separated and the rubber components are granulated into crumb rubber – 0.4 mm or less in particle size”.
Dr. Narine added, “We then use a chemical process to react the crumb rubbers at a high temperature with bitumen, which creates a product called rubberized asphalt cement”.
This material from tyres is used to coat the Demerara Harbour Bridge and other steel bridges. This year, the institute has arranged to acquire a mobile asphalt plant to allow the rubberized asphalt cement material to be applied to the bridges at location, since before the plates from the bridge had to be brought to the institute to be coated.
He noted that this material is adhesive and elastic, therefore it lasts longer and in addition provides more friction and therefore is safer compared to the materials used currently.
The institute also produces biomas briquettes from rice husk, sawdust and bagasse, which was commercially tested at the Enmore Sugar Factory. Dr. Narine said “The findings were amazing – equivalent weights of briquettes made from waste produced significantly more energy than the firewood that is currently being utilized by the factory”. The institute is on the verge of commercializing this project, as it has secured an industrial partner.
The IAST’s quiet efforts in recycling have not been well publicized, but the organization has been playing an integral and innovative role in this area. The institute also hosts the only such laboratory of its kind and capacity in the Guyana and the greater Caribbean region.