Industrial Ecology – Converted Waste to Fertilizer
In natural systems there is no waste that cannot be transformed within the circulating system. High volume material waste is not only an environmental problem, but an economic loss. The key to reclaiming waste from industrial production is to mimic the natural conversion process by creating products.
Natural rubber harvesting and processing produces raw materials used for the manufacture of rubber products. The raw material used for natural rubber processing is latex, tapped from rubber trees (Hevea brasiliensis). As global demand of rubber products is increasing, converting waste from this industrial system becomes essential.
Natural rubber processing consumes large volumes of water and energy and discharges enormous amounts of waste. The main effluent from a raw rubber-producing factory is rubber serum diluted with water. It is a clear, slightly yellowish liquid that contains formic acid used during the coagulation step. Rubber serum contains proteins, amino acids, carbohydrates and plant growth substances such as calcium, magnesium, sodium, potassium and phosphorus. Historically wastewater from processing plants is diverted through a canal, to farmers fields.
The wastewater contains nutrients (N, P, K) in available forms resulting in high potential to add value for fertilizer production. By drying the concentrated latex residue, a high phosphorus resource is captured as fertilizer. Utilization of latex rubber powder offers a solution to farms seeking an affordable phosphorus source while solving an industrial environmental problem.
Phosphorus is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (due to runoff or wastewater discharges), Phosphorus is also a primary contributor of eutrophication. To resolve the simultaneous shortage and concentrated waste streams producing excessive concentrations of Phosphorus, conversion is essential to prevent its release into the environment. While no single solution can replace consumption of phosphate rock, sustainable conversion of waste into value added products does close the loop.