New potential source of fertilizer


A recently published study focuses on a new process for converting human waste from household septic tanks into phosphorus-rich fertilizers.

Professor of Biomedicine and Chemical Engineering and Sciences Toufiq RezaPublished a new treatise with former Florida Institute of Technology researchers Nepu Saha, Kyle McGaughy and Sarah Davis of Ohio University. “Assessment of Hydrothermal Carbonization as a Sustainable Management of Domestic Wastewater in Rural Counties: A Case Study from Appalachia, Ohio” Posted in August Journal Comprehensive environmental sciences..

The main conclusion of this article is that hydrothermal treatment of septic tank waste (called septic sludge) is economically feasible and this treatment can reduce the cost of pumping septic sludge by up to 25 percent. .. Converting waste into usable fertilizer can also significantly reduce the demand for fertilizer in the study area. In this investigation, it was in the district of Athens, Ohio, a county in the Appalachian region of the state’s southeast. This work can also have a significant impact on developing countries. Benefits that underpin some of Reza’s previous studies.

In this study, the waste is converted into fertilizer by a high temperature, high pressure process called hydrothermal carbonization (HTC). HTC is a thermochemical conversion technology that can convert wet biomass into energy and chemicals without pre-drying. So far, this process has provided material that has the potential to promote the growth of inedible crops, but Reza has still tested to see if fertilizers can be used for food growth. Said you must do.

“The idea is that human wastewater contains pathogens that must be killed and sterilized,” Reza said. “High temperature and high pressure break down many of these drugs into waste products, such as antibiotics and the active ingredients in contraceptives. “

This renewable approach has the potential to financially support homeowners in addition to providing potential agricultural benefits. Almost 22 million American homes (about 25 percent of the total) use septic tanks. In Ohio, more than one million homes depend on their own treatment facilities, and the proportion of homes with septic systems is even higher in rural Appalachia. More than 25% of Ohio’s septic tanks do not perform well or fail due to lack of understanding of the need for maintenance and costly cleaning, according to Athens Municipal Health Service study . Make. To provide cleaning services, sludge haulers may charge homeowners around $ 200 to $ 500, depending on the size and complexity of the tank. This is a huge cost for rural homeowners, whose median and average household incomes are $ 24,326 and $ 48,628, respectively.

“The idea was whether we could turn their charges into something of local value and utility on behalf of homeowners who might find it difficult to afford Septage’s pumps. Someone came and turned it into fertilizer and sold it to the local community, which took the septic tank pump fee away, ”Reza said. “It was the motivation. Can we take this responsibility from the owner and make it a profitable business? “

This approach can also be good news for inland waterways. Sludge is considered dangerous because it can infect disease, is rich in nitrogen, phosphorus and potassium, and can interfere with nutrient removal. Excessive amounts of nutrients in rivers and other bodies of water can cause outbreaks of harmful algae and disrupt the reproductive endocrinology of fish.

In addition to testing fertilizers for food crop use, the researchers also plan to examine how septic tank waste disposal systems will be implemented. Reza said the ideal situation would be to have a hydrothermal treatment plant near the drainage facility, but this is not always possible in rural areas. One of the ideas they have is a mobile unit that can pick up trash, convert it into fertilizer, and move it to the next house.

Reza and the researchers are also leading a related project in Ohio, funded by the Sugarbush Foundation, with a focus on “reducing vector gravity.” Find out if wastewater treatment can reduce the number of flies and other insects. The next step is to design the pilot system and then seek approval from the United States Environmental Protection Agency.

Reza hopes that the project’s focus on rural areas will lead to better renewable resource initiatives as a whole.

“If we develop individual counties and use their own resources, it will make their counties sustainable and create a sustainable state,” he said. “Instead of developing a city, we can probably sustainably develop a rural county, which will have a significant impact on the sustainability of the United States. “


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