Press Technology



Agri-Clean™ Patent Pending: 60/347,425 The purpose of the Agri-Clean™ System is to remove solids and nutrients from animal manure wastewater. The system consists of an Internal Drum Thickener (IDT), an Agri-Press® Screw Press, a Dissolved Air Floatation (DAF) Clarifier, a twin polymer make-down system, a chemical feed system, a PLC control, a data collection system and a telephone modem. The IDT prethickens the low consistency raw manure slurry to 10-12% solids. The thickened slurry flows into the Agri-Press® and is dewatered to 35-40% solids. The liquid filtrate from the IDT and Agri-Press® is pumped to a DAF clarifier. Chemistry is added to the liquid filtrate before being injected into the DAF. The chemicals are a coagulant and a flocculent. The coagulant is used to remove soluble phosphorus and ammonia while reducing the pH and neutralizing the negatively charged suspended solids. Solids from the DAF are returned to the IDT and Agri-Press®.
In the past, livestock farms had small herds and sufficient farmland to apply manure. The rich nutrients, nitrogen, phosphorus and potassium provided valuable organic material for crops and pasture. Today the explosion of herd sizes on Concentrated Animal Feeding Operations (CAFO’s) equates to a greater concentration of residuals being applied on surrounding cropland. Without appropriate manure management a CAFO’s residuals can overload the soil with nutrients. The residuals that once added natural fertility to the soil have now become detrimental. Phosphorus, a major nutrient in manure, plays an important role in capturing and converting the sun’s energy into useful plant compounds when it is applied in moderation. When overloaded in the soil it can run off into surrounding lakes and streams depleting oxygen to aquatic life. Phosphorus also remains in the soil longer than other nutrients such as nitrogen, which crops absorb in greater quantities. The impact of phosphorus overloading is one of the major problems facing CAFO’s today. Another problem having serious consequences for CAFO’s is odor. As urban sprawl continues to penetrate deeper into rural areas, CAFO’s must be good neighbors and address odor control. The main cause of odor is anaerobic digestion in manure caused by bacteria that digest complex organics in static holding tanks or lagoons. Anaerobic digestion releases by-products that release odor into the surrounding atmosphere. The four major ingredients of odors in anaerobic digested manure are hydrogen sulfide, methane, ammonia and volatile organic acids. Some CAFO’s are installing methane digesters with generators to harness the gas to produce electricity. These systems are very expensive and tend to have a long return on investment (ROI). Even though methane digesters help reduce odors they do not separate solids or reduce nutrient levels. Press Technology & Mfg., Inc. has spent several years researching and developing equipment for mechanical separation and nutrient removal of residual waste on CAFO’s. The result of our labor is the Agri-Clean™ System. The Agri-Clean™ system is manufactured using the latest technology of mechanical dewatering combined with Dissolved Air Floatation (DAF) clarification and polymer chemistry to control odors and nutrients, while producing dry solids and clean water. The first part of our system uses an Internal Drum Thickener (IDT) to increase the raw manure slurry to 10 - 15 % solids. The rugged and durable Agri-Press® then dewaters the pre-thickened solids to 35 - 45% dry matter. The IDT and the Agri-Press® are designed to have a high capture rate to reduce the accumulation of fines in the filtrate. The remaining suspended solids from the IDT and the Agri-Press® filtrate are treated with polymer chemistry. The polymer aids separation within a DAF clarifier and binds phosphates within the solid mass. The separated solids from the DAF clarifier are sent to the IDT thickener. The Agri-Clean™ system discharge solids will be 35% or greater. The system will remove an estimated 80% of the TKN, 95% of the soluble phosphorus, 80% of the ammonia and 99% plus of the suspended solids (TSS), based on the conditions at the time of testing. The Agri-Clean™ will reduce levels of BOD and COD, but is not designed to meet specific values. The system will not remove dissolved solids, which limits the number of times the clarified water can be reused in a flush system. The benefit of the Agri-Clean™ is its ability to reduce the level of the three major problems that are restricting CAFO - growth, odor, nutrient overload and residual volume. The reduction of odors allows CAFO’s to become good neighbors and cohabitate with the urbanization of rural areas. The reduction of nutrients from the filtrate permits the application to surrounding cropland without the build-up of phosphorus and nitrate levels and the threat of runoff into local lakes, stream and reservoirs. The ability of the Agri-Clean™ to produce dry solids from animal waste slurries allows farms to store solids for alternate uses, for example bedding, soil conditioner, compost and fertilizer. The Agri-Clean™ advantage allows for a cost-effective approach to manure management. Click for Agri-Clean™ Test Results Click to return to the main Agri-Clean™ page
Definitions and Machines INTERNAL DRUM THICKENER (IDT) The thickener consists of a horizontal drum with ľ" perforated holes. The drum is externally wrapped with 40-mesh screen. A 125-psi showerhead on the outside of the drum is used to keep the screen clean. Internally the drum has helical flights and horizontal ribs to control the flow of material through the thickener. AGRI-PRESS® The Agri-Press® is a screw press designed for manure separation. A decreasing volume screw shaft is surrounded by wedge wire screen with 0.008-inch longitudinal slots. The thickened manure conveys down the shaft under gradually increasing pressure. An air operated backpressure device is used to control dryness of the discharge solids. DISSOLVED AIR FLOATATION (DAF) CLARIFIER The injection of micro bubbles and chemicals allow the incoming solids to float to the top of the rectangular DAF tank. A continuous scraping system removes the floatable solids. Heavy solids settle at the bottom of the DAF tank and are periodically discharged. Clarified water is discharged to a holding pond. TWIN POLYMER MAKE-DOWN SYSTEM The polymer used with the DAF is an emulsion based polymer that needs to be diluted with water and aged before using. The twin polymer make-down system will permit the use of one tank while the other is being prepared. The PLC controller operates the make-down system. CHEMICAL FEED SYSTEM The chemical feed system injects a measured amount of chemical into the water entering the DAF. The amount of chemical being fed depends on the type of chemical, polymer charge, gpm, pH and conductivity of the water. The chemical feed system is controlled by the PLC. PLC CONTROLLER AND MODEM The PLC controller will provide controls for pumps, IDT, Agri-Press®, DAF, twin polymer make-down system and chemical feed system. The PLC will monitor the gpm, percent solid sensor, pH sensor, conductivity and turbidity. A modular is added to the PLC that contains a modem and a dial-up system. The dial-up system will call up to five phone numbers if a problem is detected. A touch screen panel is used for inputs and display system status. The touch screen panel contains a data collection system that can be monitored through the panel or modem for a historic record of system performance. CHEMISTRY The chemistry used with the Agri-Clean™ System is a coagulant and a flocculent. These chemicals have been selected for their little or no impact on the environment and the dairy herd. Click for Agri-Clean™ Test Results Click to return to the main Agri-Clean™ page Click for Agri-Clean™ photos
Press Technology & Mfg., Inc. 1315 Lagonda Avenue Springfield, OH 45503 Phone: 937-327-0755 Fax: 937-327-0756

Agri-Clean™

Definitions and Machines