Natural Resources Conservation Service s57

USDA NATURAL RESOURCES CONSERVATION SERVICE CONSERVATION PRACTICE STANDARD ARIZONA

WASTEWATER TREATMENT STRIP (acre) CODE 635

DEFINITION CONDITIONS WHERE PRACTICE A treatment component of an agricultural APPLIES waste management system consisting of a This practice applies: strip or area of herbaceous vegetation.  Where a treatment strip is a component of PURPOSE a planned agricultural waste management system The purpose of this practice is to improve water quality by reducing loading of nutrients,  Where a treatment strip can be organics, pathogens, and other contaminants constructed, operated and maintained associated with animal manure and other without polluting air or water resources wastes, and wastewater by treating agricultural  To the treatment of contaminated runoff wastewater and runoff from livestock holding from such areas as feedlots, barnyards, areas with: and other livestock holding areas  Rapid infiltration  To the treatment of dilute wastewater such  Overland flow as milk house effluent and diluted silage leachate  The slow rate process

NRCS Field Office Technical Guide, Section IV NRCS-AZ Conservation practice standards are reviewed periodically, and updated if needed. To obtain May, 2002 the current version of this standard, contact the Natural Resources Conservation Service. 635 - 2

CRITERIA method is not appropriate for treatment of wastewater containing high concentrations of The installation and operation of the nutrients. wastewater treatment strip shall comply with all federal, state, and local laws, rules, and Contaminated runoff shall be pretreated by regulations. solid/liquid separation utilizing a facility such as a settling basin prior to discharge of liquid to Inflow to wastewater treatment strips shall be the treatment strip. pretreated as appropriate. The treatment strip shall be a uniformly graded Discharge to and through treatment strips shall strip or wide bottomed trapezoidal channel. be as sheet flow. Some means, such as a ditch, curb, or gated pipe, shall be provided to The treatment strip design shall be based on disperse concentrated flow and ensure sheet the runoff volume from the 25-year, 24-hour flow across the width (dimension perpendicular storm event from the livestock holding facility. to flow length) of the treatment strip. Land It may be designed to infiltrate a portion or the grading and structural components necessary entire volume of the design storm. This to maintain sheet flow throughout the length determination will be based on management (dimension parallel to the flow) of the treatment objectives. The portion of the design volume strip shall be provided as necessary. not infiltrated shall be transferred to a storage facility unless discharge is permitted by Permanent herbaceous vegetation consisting applicable regulations. of a single species or a mixture of grasses, legumes and/or other forbs adapted to the soil The treatment strip’s area requirements shall and climate shall be established in the be based on the soil’s capacity to infiltrate and treatment strip. Vegetation shall be able to retain runoff within the root zone and the withstand anticipated wetting and/or vegetation’s capability to utilize the nutrient submerged conditions. loading. The soil’s ability to infiltrate and retain runoff shall be based on its water holding Clean water shall be diverted from the capacity in the root zone, infiltration rate, treatment strip to the fullest extent possible permeability, and hydraulic conductivity. This unless needed to promote vegetation growth in determination shall be based on the most the treatment strip. restrictive soil layer within the root zone Treatment strips should be located outside of regardless of its thickness. The anticipated floodplains. However, if site restrictions nutrient loading shall not exceed the require location within a floodplain, they shall vegetation’s agronomic nutrient requirement. be protected from inundation or damage from a The infiltration strip design shall be such that 25-year flood event, or larger if required by the upper soil profile remains unsaturated law. except during storm events and returns to an Designs shall be based on the latest edition of unsaturated condition within two days following the Environmental Protection Agency storm events. The water table shall be either Technology Transfer Process Design Manual naturally deep enough or artificially lowered so for Land Treatment of Municipal Wastewater or that the infiltrated runoff does not mingle with other technically acceptable reference. the native ground water. Infiltration strips shall not be planned where soil features such as Additional Criteria For Rapid Infiltration cracking will result in preferential flow paths Treatment that transport untreated runoff from the surface to below the root zone. Rapid infiltration treatment refers to a specific remediation technique that utilizes the filtering Additional Criteria For Overland Flow capabilities of moderately and highly Treatment permeable soils. Treatment for this purpose shall consist of directing wastewater or Overland flow treatment refers to a specific contaminated runoff from a livestock holding microbial remediation technique that has area into a uniformly graded strip or area of minimal infiltration of wastewater. Treatment herbaceous vegetation and allowing it to flow by overland flow shall consist of the application over and infiltrate the treatment strip. This of wastewater along the upper portion of a

Conservation practice standards are reviewed periodically, and updated if needed. To obtain NRCS, NHCP the current version of this standard, contact the Natural Resources Conservation Service. October 2001 635 - 3 uniformly sloped strip of herbaceous- The design hydraulic loading shall be based on vegetation, allowing it to flow over the the more restrictive of two limiting conditions – vegetated surface for aerobic treatment to a the capacity of the soil profile to transmit water collection ditch. (soil permeability) or in the nitrogen concentration in the water percolating below The design hydraulic loading rate and the root zone. The percolate nitrate-nitrogen application rate shall be selected based on concentration leaving the root zone shall not consideration of the anticipated levels of exceed 10 mg/L. The anticipated nutrient pretreatment, quality of effluent, temperature, loading shall not exceed the vegetation’s and other climatic conditions. A maximum agronomic nutrient requirement. hydraulic loading rate of 2.0 inches per day and an application rate of eight gallons per Storage shall be provided when the amount of hour per foot of slope width shall be used available wastewater exceeds the design unless higher rates can be justified by on-site hydraulic loading rate or for strip non-operating studies. periods. The application period shall not exceed 12 Wastewater shall be applied to the treatment hours per day and the application frequency strip utilizing a method that will result in an not exceed 5 days per week unless longer even application of the entire strip and a rate application periods and frequencies can be that does not exceed the infiltration rate of the justified based on local conditions. soil.

The nutrients anticipated to infiltrate the Cultural Resources treatment strip shall not exceed the vegetation’s agronomic nutrient requirement. If this practice involves soil disturbance, the area of potential effect for each undertaking Overland flow treatment shall be constructed must be investigated for cultural resources on soils with low permeability. The design under section 106 of the National Historical shall be based on the most restrictive soil layer Preservation Act of 1966, as amended, before within the root zone. The maximum allowable soil disturbance occurs. See the NRCS permeability shall be 0.2 inches per hour Arizona Handbook of Cultural Resources unless a natural or constructed barrier within Procedures - Applicability and Exceptions the soil profile mitigates the potential of ground Section - for identification of practices that are water contamination. exempt from, or that require cultural resources The minimum slope length for the applied surveys. wastewater shall be 100 feet. Endangered Species The sloped areas to receive wastewater shall be uniformly graded to eliminate wastewater Determine if installation of this practice with ponding and short-circuiting for the length of any others proposed practice will affect any the flow. Slopes shall be equal to or greater federal, tribal, or state listed Threatened or than 2.0% but shall not exceed 8.0%. Endangered species or their habitat. NRCS's objective is to benefit these species or at least Wastewater discharged from the treatment not have any adverse effect on a listed strip shall be transferred to a waste storage species. If the Environmental Evaluation facility, a waste treatment lagoon, or other indicates the action may adversely affect a facility for further treatment and/or utilization listed species or result in adverse modification unless discharge is permitted by regulations. of habitat of listed species which has been Additional Criteria For Treating Wastewater determined to be critical habitat, NRCS will With The Slow Rate Process advise the land user of the requirements of the Endangered Species Act and recommend The slow rate process refers to a specific alternative conservation treatments that avoid remediation technique involving the application the adverse effects. of wastewater to a vegetated surface for Further assistance will be provided only if the treatment as it flows down through the plant- landowner selects one of the alternative soil matrix. conservation treatments for installation; or at the request of the landowners, NRCS may

Conservation practice standards are reviewed periodically, and updated if needed. To obtain NRCS, NHCP the current version of this standard, contact the Natural Resources Conservation Service. October 2001 635 - 4 initiate consultation with the U.S. Fish and  Statement that only viable, certified weed Wildlife Service. If the Environmental free, high quality, and regionally adapted Evaluation indicates the action will not affect a seed will be used listed species or result in adverse modification of critical habitat, consultation generally will not  Site preparation sufficient to establish and apply and usually would not be initiated. grow selected species Document any special considerations for endangered species in the Practice OPERATION AND MAINTENANCE Requirements Worksheet. An operation and maintenance plan shall be developed that is consistent with the purposes CONSIDERATIONS of the practice, its intended life, safety  More than one overland flow treatment requirements, and the criteria for its design. strip should be considered to allow for The plan shall include the following as resting, harvesting vegetation, appropriate: maintenance, and to minimize the potential  Harvest treatment strip vegetation as for overloading. appropriate to encourage dense growth,  Consider pretreating overland flow influent maintain an upright growth habit, and with solid/liquid separation to reduce remove nutrients and other contaminants organic loading, odor generation, and that are contained in the plant tissue maintenance requirements  Control undesired weed species,  Consider suspension of application to especially state-listed noxious weeds treatment strips when weather conditions  Inspect and repair treatment strips after are not favorable for aerobic activity or storm events to fill in gullies, remove flow when soil temperatures are lower than 390 disrupting sediment accumulation, re-seed F. When soil temperatures are between disturbed areas, and take other measures 390 F and 500 F reduction of application to prevent concentrated flow rate and increased application period while maintaining the hydraulic loading rate  Apply supplemental nutrients as needed to constant should also be considered. maintain the desired species composition and stand density of herbaceous PLANS AND SPECIFICATIONS vegetation Plans and specifications shall be prepared in  Maintain or restore the treatment strip as accordance with the criteria of this standard necessary by periodically grading when and shall describe the requirements for deposition jeopardizes its function, and applying the practice to achieve its intended then reestablishing to herbaceous use. Plans should include information about vegetation the location, construction sequence, and  Routinely de-thatch and/or aerate vegetation establishment. treatment strips used for treating runoff Specifications will include: from livestock holding areas in order to promote infiltration  Length, width, and slope of the treatment strips to accomplish the planned purpose  Conduct maintenance activities only when (length refers to flow length down the slope the treatment strip is dry and moisture of the treatment strip) content in the surface soil layer will not allow compaction  Herbaceous species and seed selection, and seeding rates to accomplish the  Prevent grazing in treatment strips planned purpose Treatment strips in arid or semiarid regions  Planting dates, care, and handling of the that potentially could be affected by high seed to ensure that planted materials have salinity and/or sodicity (sodium content) should an acceptable rate of survival be monitored for excessive salt and sodium buildup. If found to be excessive, an appropriate corrective action shall be taken.

Conservation practice standards are reviewed periodically, and updated if needed. To obtain NRCS, NHCP the current version of this standard, contact the Natural Resources Conservation Service. October 2001 635 - 5

Conservation practice standards are reviewed periodically, and updated if needed. To obtain NRCS, NHCP the current version of this standard, contact the Natural Resources Conservation Service. October 2001