The N-Viro Process is a patented technology process for the treatment and recycling of bio-organic wastes, utilizing certain alkaline by-products produced by the cement, lime, electric utilities and other industries. To date, the N-Viro Process has been commercially utilized for the recycling of wastewater sludges from municipal wastewater treatment facilities. N-Viro Soil produced according to the N-Viro Process specifications is an “exceptional quality” sludge product under the Part 503 Regulations.
The N-Viro Process involves mixing the wastewater sludge with an alkaline admixture and then subjecting the mixture to a controlled period of storage, mechanical turning and accelerated drying in which a blending of the sludge and the alkaline admixture occurs. The N-Viro Process stabilizes and pasteurizes the wastewater sludge, reduces odors to acceptable levels, neutralizes or immobilizes various toxic components and generates N-Viro Soil™, a product which has a granular appearance similar to soil and has multiple commercial uses. These uses include agricultural lime, soil enrichment, top soil blend, landfill cover and filter, and land reclamation.
The alkaline admixture used in the N-Viro Process consists of by-product dusts from cement or lime kilns, certain fly ashes and other products of coal, coke or petroleum combustion and by-product dusts from sulfuric acid “scrubbers” used in acid rain remediation systems and from fluidized bed coal-fired systems used in electric power generation. The particular admixture that is used usually depends upon cost and availability in local markets. In certain cases, commercial lime may also be added to the admixture. We are a distributor of alkaline admixture and are responsible for quality control of the admixture.
N-Viro Soil is sold for agricultural use as a bio-organic and mineral fertilizer with agricultural liming and nutrient values, as landfill cover material, as a topsoil blending ingredient and for land reclamation projects. We estimate that approximately twenty percent of the N-Viro Soil produced is utilized at landfills for cover material, small amounts are sold for land reclamation and similar projects, and a substantial portion of the remainder is sold for agricultural use or as a topsoil blend. Although the use of N-Viro Soil is not subject to any federal regulations or restrictions, each N-Viro facility is typically required to obtain a state and/or local permit for the sale of N-Viro Soil. In addition, many states and/or local governments require site-specific permits for the use of sludge products in bulk amounts.
Below is a narrative of the N-Viro process.
A. Biosolids Dewatering and/or Receiving
The single most critical cost component to every beneficial use option is the ability to get as much water out of the biosolids as possible in the dewatering process. An investment into state-of-the-art dewatering equipment is always worth the analysis. The N-Viro process can receive biosolids as low as 12% solids, however, the higher the solids the better. Dependent upon facility design biosolids can be received directly from dewatering into the processor, tipped onto a receiving floor, or delivered into a receiving bin. A key aspect regarding receiving is the process allows for a wide spot in the line which allows operators to run the equipment automatically which enables more time to focus on the efficiencies of dewatering.
The dewatered sludge is mixed with N-Viro’s alkaline admixture. The mixing equipment is designed to accurately proportion and blend the biosolids with any combination of alkaline materials at output rates of 5 to 100 tons per hour of total mixed materials. This blended material is then conveyed to heat pulse cells or a mechanical drying system. The admixture’s are delivered via pneumatic truck and stored in silos. The alkaline material is then fed typically by auger to the mixing unit.
C. Heat Pulse Bunker
A chemical reaction, or “heat pulse”, occurs between the biosolids and the alkaline admixture raising the temperature to between 52-62° C and the pH level > 12. This reaction, combined with other stresses, kills disease-causing bacteria, pathogens and eliminates noxious odors. Strict temperature control ensures the survival of valuable and useful normal soil micro flora. (When utilizing the mechanical drying option, the heat pulse phase will follow the drying phase.) Expensive additional enclosed vessel systems are not required for the N-Viro process. The Process is regulated under 40 CFR Part 503 rules as Alternative 2 and as Alternative 6. Alternative 2 is a generic description of the N-Viro Process (temperature > 52° C for 12 hours, pH > 12 for 72 hours, and solids > 50 %), while Alternative 6 includes processes that have been approved by EPA’s Pathogen Equivalency Committee as equivalent to Processes to Further Reduce Pathogens (PFRP). Equivalency was granted to N-Viro in 1988.
D. Accelerated Drying Techniques
Windrow Drying: When utilizing windrow drying, a windrowing device such as a Scarab, Cobey Composter, Athey, or Brown Bear is used. The material is further dried and granulated through the windrowing action. A 2% per day increase in solids can be achieved using this method. The majority of N-Viro facilities operate some form of windrow drying.
Accelerated Drying by Bulking: A third alternative is to dry the product by adding significant quantities of a bulking material to achieve the minimum solids requirements. Bulking can be utilized to simply reach the minimum standards of 50% solids or additional bulking can be utilized to meet other product requirements. Bulking can be utilized to eliminate the need for windrowing or mechanical drying, however N-Viro cautions that additional mixing should also take place to ensure the adequate mixing of biosolids and sludge for odor control and product stability.
The ability to store product is critical to the success of any distribution program for large volumes of organic materials. Because of its stability, N-Viro Soil can be safely stored for extended periods of time, in the open or under a roof, making it ideal for seasonal use. (When utilizing N-Viro Alternative #1, product must be stored for 30 days and reach 65% solids.)
N-Viro Soil is normally shipped by the truckload to the customer. Its physical characteristics are tailored to its utilization in standard materials handling equipment. Existing markets include agricultural limestone substitute/low analysis fertilizer, land reclamation, soil amendment/urban soils, soil blend ingredient, and landfill cover material.http://nviro.com
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