EnVessel Pasteurization™

EnVessel Pasteurization™RDP Technologies, Inc.EnVessel Pasteurization™ reduces biological, municipal wastewater-sludge pathogens and vector attraction properties. This patented process pasteurizes sludge and produces sludge that is pathogen free.• Pasteurized sludge is ideal for land and agricultural application.• Pasteurized sludge may be applied to lands without need for site-specific permits,according to federal regulations and, thus may be marketed, distributed, and sold as fertilizer.EnVessel Pasteurization™ uses time, temperature, and high pH to destroy harmful pathogens.• Specialized equipment heats sludge solids and lime increases pH.• Extended processing ... windrowing, aerating, or drying ... are not required.From start to finish, the process needs only 30 minutes and EnVessel Pasteurization™ can be operated under $10 per wet ton.RDP manufacturers and designs the patented EnVessel Pasteurization™ equipment and controls.• Equipment purchasers receive a license to use the patented EnVessel Pasteurization™process without ongoing royalty payments.• Licensees are free to purchase process alkaline materials from any source.A typical flow sheet consists of the following steps:The ThermoBlender™receives and preheats sludge.Lime from a lime storagebin is added to theThermoBlender™ at a proportion-al rate to the sludge feed.The ThermoBlender™ mixessludge with lime and heats thecontents to approximately 700C.(1570F). The heated sludge/limemixture discharges to thePasteurization Vessel.The Pasteurization Vesselstores the entire mass of mate-rial, for approximately 30 min-utes, in an enclosed, insulatedenvironment, maintaining theproper temperature over time todestroyharmful pathogens. The vessel isheated to temperatures that over-come any possible heat losses inits contents. Vessel sensors pro-vide for temperature records thatdemonstrate compliance withregulations.EnVessel Pasteurization™12345Pasteurization has been used foryears to remove or kill harmfulpathogenic organisms.Pasteurization temperatures killpathogenic organisms while limeprevents regrowth of organisms.The result is an end product thatcan be stored for extended periodsof time. The process is so complete,RDP unconditionally guaranteesthat the end product will meetU.S.E.P.A. criteria for Class Apathogen reduction and vectorattraction reduction levels. ( 40 C.F.R. Part 503.32 and 503.33)From the lime storage silo to theconveyor used to load trucks withpasteurized sludge, RDP bringsover 15 years experience to everysystem component. RDP is the onlysupplier with experience inmanufacturingand designingall componentsand equipmentnecessary toprovide a complete system.Mixing sludge and lime is the mostimportant sludge-stabilizing step.RDP is the largest U.S. manufac-turer of sludge/lime mixing equip-ment. RDP knows the variables necessary to ensure uniform andcomplete mixing of sludge andlime.RDP’s patented mixing technologyproduces a unique spiral action thatprovides for optimum lime-sludgesurface contact and a highly mar-ketable granular end product.By combining heating and mixingin a single apparatus, EnVesselPasteurization™ reduces the num-ber of processing steps and capitalcost. RDP’s ThermoBlenders™ andThermoFeeders™ utilize the samepatented technology as our stan-dard sludge/lime mixers with specialized heating equipment.ThermoBlenders™ and ThermoFeeders™ use heated mixingrotors and a heated, insulated mix-ing enclosure to efficiently transferheat in a compact design. Materialis simultaneously and uniformlymixed and heated by combiningRDP’s patented mixing technologywith heated mixing rotors.Because the rotating and heatedrotors are submerged in the materi-al, the efficiency is extremely high. Because all heat from the rotorsmust radiate out and into thematerial, RDP developed a specialized method of heatingrotors. Inside the rotors, RDP putheat tubes.The heattubes areelectricallyheated to produce temperatures upto 1,0000F. The internal heat tube isa self contained unit which can beremoved and replaced easily.Mixing rotors are built to special-ized standards and tolerances tohouse the heat tubes and to allowfor expansion during the heatingand cooling cycles. Special end connections allow for easy removaland replacement of internal heattube assemblies.RDP’S patented mixing action provides a granularend product.Internal heat tubeassembly shown par-tially removed fromthe mixing rotor.Overall view of a 1.5 dry ton per hoursystem utilizing aThermoFeeder™,ThermoBlender™and PasteurizationVessel.EquipmentFeatures/DescriptionThe Pasteurization Vessel providesapproximately 30 minutes of reten-tion time at the elevated tempera-ture. The vessel is encased with aminimum of 2” of insulation andprotective steel cover. Speciallydesigned insulation protects thevessel contents from cooling.The vessel design also providessupplemental heat. The combina-tion of supplemental heat and insu-lation ensures the entire mass ofmaterial maintains the proper tem-perature, including the very outsideedges. No extra lime or heat arerequired to overcome any heat loss. The materialwill not dropin temperaturewithin the Pasteurization Vessel.The Pasteurization Vessel is fur-nished with multiple temperaturesensors. The sensors are used toverify that the material is maintain-ing the proper temperature duringthe heat pulse step. Temperaturesensors can be connected to com-puterized controls to provide documentation of compliance withall regulations. E.P.A. regulations require munici-palities to certify, under penalty oflaw, that the treated sludge com-plies with all regulations. RDP’sEnVessel Pasteurization™ providesthe documentation and confidenceto sign the EPA certificationsrequired under 40 C.F.R. Part503.17.250 cubic footPasteurization Vesseldesigned to provide30 minutes of retention time.Pasteurization vessel with coversremoved showinginsulation and temperature sensors.Theory of EnVessel Pasteurization ™Lime pasteurization relies on a high pH sludge maintaining a 70o C (158o F)temperature for 30 minutes to destroy pathogenic organisms. The heat generat-ed from the exothermic reaction of lime and water in the sludge raises the sludgetemperature.RDP’s EnVessel Pasteurization™ process uses supplemental heat to reduce theneed for a high lime dosage and, thus, costs.Calculations show that EnVessel Pasteurization™ saves lime and predicts thequantity of lime required to pasteurize one ton of sludge cake containing 18 %dry solids.Determine liquid and solid fraction in one-ton of sludge:2,000 lbs Solids 2,000 lbs x 18% = 360 lbs. dry solidsLiquid 2,000 lbs x 82% = 1,640 lbs. waterCalculate heat required to elevate the sludge temperature from 68o F to158o F. using the following formula:Weight(lbs). x Spec. Heat (Btu/lb/oF) x Temp. Rise (oF) = Btu’s RequiredSolids: 360 lbs x 0.30 x 90o = 9,720Water: 1,640 lbs x 1.0 x 90o = 147,600——————-Total 157,320Calculate lime required based on 490 Btu’s/lb., CaO’s heat of reactionwith water:157,320 Btu’s ÷ 490 = 320 Lbs. of CaO or344 Lbs of Lime @ 93 % CaOCosts for Lime Pasteurization based on $75.00/ ton for lime:344 Lbs of lime x $75 per ton = $ 12.90/ton cakeBy using supplemental heat, EnVessel Pasteurization™ reduces the amount oflime required and the cost for operating pasteurization. The savings by usingsupplemental heat can be calculated by modifying the previous calculations asshown below:Reduce lime addition to 30% by a dry weight basis:360 lbs. sludge dry solids x 30% = 108 Lbs. of limeCalculate the exothermic heat available from the lime:108 lbs. lime x 93% CaO x 491 Btu’s/Lb. CaO = 49,316 Btu’sCalculate supplemental heat required:( From step #2) 157,320 Btu’s Required - 49,316 Available From Lime addition––––––––––108,003 Btu’s Required from supplemental heatCosts per ton of cake using supplemental heat:108 Lbs. of Lime x $75.00 per ton = $ 4.05108,003 Btu’s x $.075 per Kw-Hr. = 2.37————-$ 6.42 per ton of cakeEnVessel Pasteurization™ reduces lime consumption by 164 lbs./ ton of cakeand reduces cost from $12.90 to $6.42 / ton.Step 1Step 3Step 4Step 5Step 6Step 7Step 8Step 2Lime Dosage Sludge 34% 112%(Dry weight basis) FeedTotal Nitrogen 6.3% 5.2% 1.5%Calcium Carbonate N/A 27% 72%EquivalentLime Dosage Sludge 34% 112%(Dry weight basis) FeedSupplemental heat reduces theoperating costs by reducing theamount of lime needed to obtainpasteurization temperatures. Thereduced lime increases the value of the end product. The ratio ofnitrogen to lime more closelymatches the agronomic demand forproper crop production as seen byactual data from field test. In comparison tohigh-lime sludgeproducts, a low-limesludge product maybe applied at higherrates per acre, requir-ing less land and,therefore havinggreater marketability.EnVesselPasteurization™offers the followingadvantagesGuaranteed Class A Low operating costsLow capital costsSingle source responsibility forpathogen-reduction;equipment andprocess guaranteeHigh value agricul-tural end productThe equipment and process described are protected by one or more US or foreign Patents 5,013,458; 5,186,840; 5,229,011; 5,401,402; 5,346,616; 5,405,536; 5,433,844;5,618,442; 5,554,279 and additional US and foreign patents pending. ThermoBlender™, ThermoFeeder™, and EnVessel Pasteurization™ are trademarks of RDP Technologies, Inc.12345RDP Technologies, Inc. Practical Technologies... that Simply Perform2495 Boulevard of the Generals Norristown, PA 19403www.rdptech.com Phone: (610) 650-9900 Fax: (610) 650-9070