Revenue Development in Dry Scrubber Media Replacement
When a client came to GCES with a zero waste initiative we had to find a solution for their spent dry scrubber media. We provided them a solution that not only met their zero waste initiative but also allowed opportunity for financial recovery of media replacement costs.
Dry scrubber media, also known as iron sponge sulfide, is composed of iron oxide, elemental sulfur, wood fiber, water, soda ash and limestone.
There are many options for the disposal of spent iron sponge with the most common being simply by spreading the spent media onto an area of land and burying it with a light earth cover. In urban areas the material is generally accepted with EPA approval at a sanitary landfill. In recent years revenue streams and partnerships have been developed between the disposers of the spent media and the agricultural community. In these scenarios agricultural uses for iron sponge include in the farming of tomatoes and coniferous trees such as Christmas trees.
These relationships developed as the demand for alternative disposal methods grew. Spent media contains elemental sulfur (sulfur) and iron oxide (iron) which are both used as primary ingredients in fertilizers to fix depleted soil and repair unbalance pH levels resulting in improved and often ideal growing conditions. Spent iron sponge can now be provided for agricultural uses either for free or through the development of an additional revenue stream through resale.
Sulfur Deficiencies in Tomato Production
Crops that are grown in peat substrates, areas with little fertilizer usage or in fields without regular crop rotation face ground depletion. Tomato plants grown in soil lacking in sulfur are shorter in height, have stiff leaves, stems and veins and are often various colors of yellow and purple in appearance. Sulfur is key in the formation of several compounds that provide tomatoes with their flavor. Sulfur is a main organic component for protein synthesis and is part of the formation of the amino acids methionine, cysteine and cystine. Often resembling nitrogen deficiency, sulfur deficiency greatly reduces crop output as seen in the chart to the right.
Iron Interaction in Tomato Nutrition
While sulfur deficiencies alone cause a decrease in production it must also be mentioned that the correlation between sulfur and iron has a similar effect as a result of the resulting soil health issues. Soils that are becoming depleted in sulfur face insolubility in the soil matrix as iron is unable to be properly absorbed without the availability of sulfur. This deficiency seems to prevent the development of typical responses in tomatoes. In studies overall growth of tomato seedlings was severely reduced in environments with iron and sulfur deficiencies. Given that both are essential elements this is not surprising and further proves that plants thrive in environments with complete, nutrient rich soil solutions.
Soil PH Management in Christmas Tree Production
One of the effects of sulfur on soil is that it acts as an agent in managing pH levels. When sulfur is added to soil it lowers pH and begins to repair depleted soil. The production of coniferous trees, including Christmas trees, requires soils with low pH values. Most common Christmas tree varieties are native to areas with naturally acidic (or low pH) soils traditionally in higher elevations. To improve crop yield Christmas tree farmers must utilize additives to configure soil pH. One of the most common agents for lowering pH is sulfur. Sites that have been overused or land that has been converted from other crop types is particularly limited in their ability to continue production levels without first lowering pH.
Note: With the recent decreases in acid rains additional demands for sulfur have occurred in many agricultural production facilities to maintain ideal growing conditions. This has increased the demand for materials and fertilizers containing sulfur.
Dry scrubber media disposal options
Additional options for the disposal of dry scrubber media include spreading onto existing land for natural decompensation or landfill disposal. The EPA states that landfill disposal is an acceptable method of disposal of dry scrubber media.