United States Department of Agriculture 634-CPS-1

NRCS, NHCP

July 2021

NRCS reviews and periodically updates conservation practice standards. To obtain the current 

version of this standard, contact your Natural Resources Conservation Service State office or 

visit the Field Office Technical Guide online by going to the NRCS website at 

https://www.nrcs.usda.gov/ and type FOTG in the search field. 

USDA is an equal opportunity provider, employer, and lender.

Natural Resources Conservation Service 

CONSERVATION PRACTICE STANDARD 

WASTE TRANSFER 

CODE 634 

(no)

DEFINITION 

A system using structures, pipes, or other conduits installed to convey wastes or waste byproducts from

an agricultural source to a storage facility, treatment facility, or land application site. 

PURPOSE 

This practice is used to accomplish one or more of the following purposes: 

• Prevent nutrient transport to surface or ground water 

• Prevent transport of pathogens to surface or ground water 

CONDITIONS WHERE PRACTICE APPLIES 

The waste transfer system is included as a component of the agricultural production area, storage facility,

treatment facility, and land application areas of the agricultural operation. 

The practice applies where it is necessary to transfer waste material generated by livestock production or

agricultural product processing between the generation site, storage facility, treatment facility, handling

area, loading area, or land for agronomic application. 

This practice does not apply to hauling waste material with equipment or vehicles. 

CRITERIA 

General Criteria Applicable to All Purposes 

Laws and regulations 

Notify landowner and/or contractor of responsibility to locate all buried utilities in the project area, including

drainage tile and other structural measures. The landowner is required to obtain all necessary permits for

project installation prior to construction. Plan, design, and construct the waste transfer system to meet all

Federal, State, Tribal, and local laws and regulations. 

Safety 

Include appropriate safety features to minimize the hazards of the facility. Provide warning signs, fences,

ladders, ropes, bars, rails, and other devices, as appropriate, to ensure the safety of humans and

livestock. Ensure that proper ventilation and adequate warning signage is provided for waste transfer

structures in an enclosed facility or confined area, as necessary, to prevent explosion, poisoning, or

asphyxiation. 

Include a water-sealed trap and vent or similar devices where necessary to control gases from a pipeline

entering an enclosed building or reception pit. 
Prevent tractors and other equipment from slipping into waste collection, storage, or treatment facilities by

placing barriers on push-off ramps. 

Provide covers or barriers, such as gates, fences, grates, etc., at openings to waste transfer components

and manure storage structures. Secure to prevent accidental entry by humans and livestock. 

Protect pipes at risk of being damaged by equipment or livestock by placing fences or markers along the

pipe. 

Provide a secure cover or otherwise restrict access to any manually operated in-line valves of a discharge

pipe from a waste storage structure to prevent unauthorized release of effluent. 

Structural design 

Design structures with reinforced concrete, steel, wood, or masonry materials in accordance with NRCS

National Engineering Manual (NEM) (Title 210), Part 536, “Structural Engineering.” Account for all items

that will influence the performance of the structure, including load assumptions, durability, serviceability,

material properties, and construction quality. Ensure that the material used for a fabricated structure is

compatible with the waste product being transferred. 

Structures 

Structures, including concrete reception pits, tanks, hoppers, manholes, and channels used for waste

transfer, prefabricated or cast-in-place, must meet the criteria in NRCS Conservation Practice Standard

(CPS) Waste Storage Facility (Code 313) for liquid tightness and structural strength, regardless of

materials used for construction. 

Design all structures, including those that provide a work area around pumps or other equipment to

withstand the design static and dynamic loading. Design structures to withstand earth and hydrostatic

loading as specified for comparable structural criteria in NRCS CPS Waste Storage Facility (Code 313). 

In locating structures, utilize existing topography to the greatest extent possible to generate head on

effluent flow and reduce pumping requirements. 

Investigate the subsurface conditions (e.g., depth to bedrock, soil classification, water table, etc.) when

locating and designing structures. 

Use NRCS CPS Roofs and Covers (Code 367) to design roofs or covers where needed for structures. 

Reception pits — Specifics 

Size reception pits to contain a minimum volume of one full day’s waste production. Provide additional

capacity for reception pits receiving stormwater runoff to contain the volume of precipitation and runoff

from the 25-year, 24-hour storm plus any required freeboard and emergency capacity. Design the

reception pit to be protected from inundation or damage from a 25-year flood event when located in the

100-year floodpain. Reducing a reception pit design volume by flood routing the design storm runoff

volume may be used only when there is dependable backup power supply for pumps and where no

impact to surface water can occur should the reception pit pump fail. 

Design floor openings with structures that receive manure from scrape alley collection to ensure

unrestricted access for the material being scraped. In the absence of evidence to support an alternate

design, provide the floor opening with a minimum area of 9 square feet, having one dimension of that

opening 4 feet or larger. Equip floor grate with openings wide enough to pass the waste and engineered to

support the anticipated live loads. Provide safety features to prevent accidental entry to the waste

reception pit. 

Design curbs, intended to convey waste, to be of sufficient height to ensure all waste flows into the

transfer structure. Design curbs to be anchored to withstand working loads. 

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Pipelines and conduits — General 

Design pipes and other conduits considering the waste material properties, management operations, pipe

exposure, static and dynamic loads on the pipe, working pressure, transfer system pressure rating,

required capacity and all applicable design factors. Pipe pressure rating required may need adjustment

based on effluent temperatures and consistency. 

Use watertight or sewer grade pipes and connection devices for waste transfer pipes. The type of liquid

waste material and the total solids content will determine the pipe designs needed to convey the required

flow without plugging. 

Provide cleanout access for all pipes transferring waste material to allow for removal of settled solids or

obstructions. Space pipe cleanouts at a maximum interval of 150 feet along the pipe length, or a

maximum interval of 300 feet along the pipe length if bidirectional cleanouts are used. A pipeline

intervention device, such as a foam cleanout ball, is an acceptable method of cleaning out pipes instead

of a cleanout access. Incorporate pipe cleanout methods into the design and describe the methods in the

operation and maintenance plan. 

Design the pipe or conduit from the collection facility to have a minimum flow rate equal to the maximum

anticipated design flow. Design flow should be a 25-year, 24-hour event to prevent discharge from the

system, otherwise, use a design flow that is required for system operation. 

Design the pipe to empty the storage or treatment facility in accordance with the planned application rates

outlined in the comprehensive nutrient management plan. 

Protect pipes exposed to sunlight from ultraviolet (UV) deterioration by selecting UV-resistant pipe

materials or by painting the pipe exterior to withstand UV damage throughout the intended life of the pipe. 

Install pipe properly at all locations to accommodate any traffic crossing, farming operations, frost depth,

subsurface saturation, or bedrock elevations. Protect pipe from uplift if subjected to hydrostatic forces.

Separate pipe installed near bedrock with at least 6 inches of bedding material. Excavation and removal of

bedrock is acceptable to provide bedding depth. 

Design transfer pipe to be insulated, heated, buried below anticipated frost depth, constructed of freezeresistant material, or installed such that it can be drained after each use by gravity or compressed air

when cold weather operaton is planned. 

Taking into account the designed outflow flow rate, size a transfer or lift station to accommodate the peak

flow where a station along a pipe is needed for transition of direction or change in elevation and no

additional flow will be added to the pipe at that station. Design the station using the reception pit criteria

for a station receiving gravity flow and pumping the outflow. 

Install pipes with appropriate backflow prevention devices, when applicable. 

Install air vents and vacuum relief valves where necessary to eliminate air locks, as well as to protect the

pipe against negative pressures. 

Pipelines — Pressure 

Select pipeline and appurtenance material that meet the design working pressure criteria of the system.

Include in the analysis any air and water pressures used to clear the pipeline. 

The pipeline working pressure must not exceed 72 percent of the pipe rating. 

Provide thrust control designed in accordance with NRCS National Engineering Handbook (NEH) (Title

210), Part 636, Chapter 52, “Structural Design of Flexible Conduits,” for all buried pressure pipelines 4

inches and larger in diameter and for fittings and valves. Mechanical joint restraint may be used and must

be certified by the manufacturer as adequate to withstand the unbalanced thrust forces in the system, as

computed in 210-NEH-636-52. 

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Maintain the integrity of a wall or liner at pipe penetrations of waste storage structures, reception tanks,

and channels. Protect the pipeline where it penetrates the liner of a waste storage facility by providing a

cast-in-place concrete restraint or other support, as necessary. Provide pipe restraint where pipeline

movement may damage the integrity of the pipe, wall, or liner system. 

For a pumped system, design so that the velocity in the pipeline, when operating at system capacity, will

be between 3 and 8 feet per second unless surge protection that is adequate to prevent damage from

sudden blockages or water hammer is provided. Limit the velocity in the pipeline to 5 feet per second or

less if the transfer pipe is not buried or securely fastened down. Velocity in the pipeline may exceed 5 feet

per second without a surge analysis if the pipeline is buried or otherwised secured, installed without gates

or valves, and discharges freely to a tank or pond. 

The 3 feet per second lower limit for velocity in the pipeline does not apply to a system that is powered by

a pump such as a ram plunger or piston type pump that operates by pushing semisolid waste material in a

periodic stroke cycle. 

Install a check valve near the outlet of each pump except where backflow is incorporated into the design. 

Provide a pressure relief valve after the check valve, near the pump(s) to protect the pipeline against any

pump shutoff head due to a blockage (unless the pump shutoff head is less than the working pressure of

the transfer system). 

Provide a pressure relief valve or properly sized water hammer arrestor on the pressure side of shutoff

valves to protect against water hammer due to the sudden closing of a valve. 

Size pressure relief valves to be no smaller than one-fourth inch for each inch of the pipe diameter. Set

pressure relief valves to open at a pressure no greater than 5 pounds per square inch above the transfer

system working pressure. 

Pipelines — Gravity 

In a gravity flow pipe system, a minimum head is required depending upon the consistency of the material.

See table 1. 

Table 1: Minimum Required Hydraulic Head and Consistency 

For manure gravity pipes over 100 feet in length, increase minimum feet of head by an additional 1

percent of the pipe length exceeding 100 feet. Design for a minimum velocity of 3 feet per second. 

Minimum diameter of gravity pipe is 24 inches for heavily bedded manure, including sand-laden manure. 

Convey waste into and through the pipe to minimize ponding in the production area. Design the gravity

pipe to follow as direct a route as possible. Horizontal curves or bends in the pipe joints of a gravity pipe

require special design considerations except for minor deflections of less than 10 degrees. 

Account for the process of sand settling out of the waste stream in a gravity flow design that transfers

sand-laden manure. The minimum gravity pipe flow velocity for sand-laden manure is 5 feet per second.

Design transfer systems to handle potential loss of pipe integrity due to internal erosion by the materials

being transported for a flow velocity exceeding 6 feet per second. 

For a flume system with slurry manure, limit the design depth of flow in the pipe to 50 percent of the pipe

depth to maintain the scouring effect of the flow. 

Minimum Feet of Hydraulic Head Consistency

4 feet heavily bedded undiluted manure

2 feet slurry or semi-liquid manure

<1 foot liquids and 1:1 dilute liquid manure

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Install a minimum of two manually operated in-line valves, with one located as close to the storage facility

as practical, for a pipeline designed to gravity discharge liquid waste from a waste storage or treatment

facility. If an automatic valve is used for gravity loading or transfer, the automatic valve will be in addition to

the two manually operated in-line valves. 

Other conduits 

The minimum design velocity for waste transfer in open ditches and channels is 1.5 feet per second. 

A minimum concrete thickness of 5 inches is required for a reinforced cast-in-place concrete-lined ditch or

channel for waste transfer. 

Pumps 

Use NRCS CPS Pumping Plant (Code 533) for a waste transfer pump where needed. 

Select the pump to transfer the waste material at the system pressure head and rate required. Determine

the type of pump by the consistency of the material and the type of solids. Use pump manufacturer’s

recommendations for the installation requirements. 

Correct the total dynamic head for viscosity and specific gravity of the liquid waste used in pump selection.

Reference 210-NEH, Part 651, Chapter 11, “Waste Utilization,” for increased friction losses caused by

higher fluid viscosity, and 210-NEH-651, Chapter 12, “Waste Management Equipment,” for pump selection

guidance. 

Agitators 

Include agitators, as needed, to facilitate pumping of liquid or slurry waste for transfer. Size the agitation

equipment to provide adequate agitation of the volume of storage. Select equipment compatible with the

type and consistency of the waste material. Base requirements for agitator sizing, installation, and

operation on manufacturer’s recommendations. 

Solid/liquid waste separation 

Use NRCS CPS Waste Separation Facility (Code 632) to separate a portion of the solids from the manure

or liquid waste stream, as needed. 

CONSIDERATIONS 

General Considerations 

Consider economics (including design life), overall nutrient management system plans, and health and

safety factors. 

Time and locate agitation and transfer activities to minimize odor formation and the breeding of insects

within the material. 

Cover and/or minimize the disturbance of material to reduce the likelihood of air emissions, hydrogen

sulfide formation, and release of particulate matter, volatile organic compounds, methane, and ammonia. 

Consider abandonment, relocation, or additional floodproofing for existing reception structures located in

flood-prone areas. For additional information on floodproofing structures, see “Floodproofing NonResidential Buildings” (FEMA P-936, 2013). 

Transfer operations 

Install permanent aboveground or buried pipes to replace hoses and temporary pipes that are used on a

regular basis to transfer waste. 

Protect storage structure liners from hydrostatic soil pressures that may be caused by preferential flow

paths along the outside of the installed pipe. 

Consider a positive displacement pump for liquid waste with total solids exceeding 8 percent. 

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Increase the total dynamic head up to 30 percent for pumping manure slurries with 3 to 8 percent total

solids (wet basis). 

Use a wet sump and agitation pump to reduce solids separation within the gravity reception structure. 

Select a pump with a low speed for manure slurries which contain abrasives such as sand. 

Use a semi-open impeller pump to handle manure slurry with straw, twine, hair, and sludge. Pumps with

cutting knives and recirculation agitation capacity also reduce plugging. 

Install a cleanout or vent riser within 10 feet of the reception structure and other grade change locations

on gravity transfer systems to reduce the risk of an air lock in the pipe. 

Use premanufactured manholes as risers at stations to change direction for needed transitions. 

Consider the operating space requirements of loading and unloading of equipment in the vicinity of the

transfer components. 

When applicable and compatible, consider the dual use of waste transfer pipelines for irrigation water

delivery. 

Install a locator wire in the trench with transfer pipelines. 

Consider corrosion resistance and water tightness in the selection of pipe material and joints due to the

nature of the waste material. 

Consider the potential for struvite phosphate (magnesium ammonium phosphate) mineral deposition in

smaller diameter pipes and places where there is high turbulence such as pipe connections and valves.

Preventative measures may be needed, such as acid washing the pipe to prevent the buildup of deposits. 

Consider the need for additional check valves, cleanouts, vent risers, knife valves, anti-siphon protection,

and vacuum relief valves and open-air breaks, as appropriate, on all pipe systems. 

Use leak detection methods and equipment for monitoring and periodic pressure testing of waste transfer

systems installed in sensitive areas having large daily flow volumes, long flow lengths, or high flow

pressures. 

Post a warning sign on all risers indicating the pipe pressure rating. 

When exporting solid waste material off-farm, consider NRCS CPS Waste Recycling (Code 633). 

PLANS AND SPECIFICATIONS 

Prepare plans and specifications for constructing a waste transfer system that describe the requirements

for applying this practice to achieve its intended use. 

• Construction plans and specifications must include a location map, plan view, profiles, cross

sections, details and specifications of all structures, etc., to ensure that the project can be properly

constructed. 

• NRCS acceptance may require pressure testing of a pressure pipe system prior to waste transfer

service. If required, include the test protocol and results in the as-built documentation. 

OPERATION AND MAINTENANCE 

Prepare an operation and maintenance (O&M) plan for review with the landowner or operator responsible

for the application of this practice. Provide specific instructions in the O&M plan for proper operation and

maintenance of each component of this practice and any detail needed for the level of repairs to maintain

the effectiveness over the useful life of the practice. Include— 

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• Evaluating the overall functionality of the waste transfer system for possible malfunctions that could

lead to a spill or release of waste material. Address the identified potential failures in the inspection

procedures of the O&M plan. Prepare an emergency response plan to be implemented in the event

of such a failure. 

• Agitating liquid or slurry waste material adequately prior to transfer. 

• Flushing pipes used for transferring waste material with clean water after use and to reduce the risk

of gas buildup and pipeline explosion. 

• Periodically removing solids from conveyance conduits such as concrete-lined ditches, grates, etc. 

• During outbreaks of disease, handling waste products according to the State veterinarian guidance

on biosecurity for animal waste material. 

• Sanitizing equipment leaving the farm, as appropriate, to prevent the spread of disease during an

outbreak. 

• Documenting use of confined space entry points and signage requirements and their review prior to

entering areas with possible gas buildup or asphyxiation concerns. 

REFERENCES 

Federal Emergency Management Agency. 2013. FEMA P-936, Floodproofing Non-Residential Buildings.

Washington, D.C. 

USDA NRCS. 2009. National Engineering Handbook (Title 210), Part 651, Chapter 10, Agricultural Waste

Management Systems Component Design. Washington, D.C. https://directives.sc.egov.usda.gov/. 

USDA NRCS. 2013. National Engineering Handbook (Title 210), Part 651, Chapter 11, Waste Utilization.

Washington, D.C. https://directives.sc.egov.usda.gov/

USDA NRCS. 2011. National Engineering Handbook (Title 210), Part 651, Chapter 12, Waste

Management Equipment. Washington, D.C. https://directives.sc.egov.usda.gov/

USDA NRCS. National Engineering Handbook (Title 210), Part 642, Chapter 2, National Construction

Specifications. Washington, D.C. https://directives.sc.egov.usda.gov/

USDA NRCS. National Engineering Handbook (Title 210), Part 642, Chapter 3, National Standard Material

Specifications. Washington, D.C. https://directives.sc.egov.usda.gov/

USDA NRCS. 2005. National Engineering Handbook (Title 210), Part 636, Chapter 52, Structural Design

of Flexible Conduits. Washington, D.C. https://directives.sc.egov.usda.gov/

USDA NRCS. 2017. National Engineering Manual (Title 210), Part 536, Section 536.20, Design Criteria for

Reinforced Concrete Structures. Washington, D.C. https://directives.sc.egov.usda.gov/

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