Comprehensive Study Guide on Closed Systems, Custom Blends, and Container Management in Utility Arboriculture

Specifications and Standards of Returnable, Reusable (R/R) Supply Containers

• Material Composition: Returnable, reusable (R/R) containers are manufactured from recyclable, translucent, and chemically resistant plastic designed for repeated field use.

• Service Life: R/R supply containers have an expected operational service life of approximately $5\,\text{years}$ or $30\text{ return cycles}$.

• Regulatory Compliance: Containers meet United Nations (UN) and Department of Transportation (DOT) standards, along with Class II container and hazardous waste requirements in the United States.

• Mandatory Standards (Effective August 2011): Regulations dictate that every returnable container must feature a unique identification number and a tamper-evident seal attached directly to the closed connection valves.

• Required Container Information (Goodfellow and Holt 2011):

  • Official EPA labels for every herbicide product contained within, including EPA registration numbers.

  • Exact concentrations of all formulation ingredients, encompassing active ingredients, diluents, and adjuvants.

  • Specific lot or batch numbers for quality control and tracking.

  • Mixing and dilution instructions tailored to the specific spray tank size in which the mixture will be utilized (expressed either as graduated units on the supply container or as a numerical ratio).

  • Clear identifiers for both the utility (the owner) and the applicator (the owner's agent in utility vegetation management).

• Volumetric Graduations: Supply containers feature external graduated markings in both English and metric scales, allowing operators to determine liquid volumes directly through the translucent plastic walls.

Closed Delivery Systems and Transfer Point Connections

• Closed Interlocking Valves: Each returnable, reusable supply container must be equipped with a mechanical, leak-proof, closed interlocking valve or connection to minimize applicator exposure and eliminate spills.

• Transfer Point Requirements: A closed connection must be maintained at every transfer point where herbicide is moved between containers or from a container into a spray tank. All closed connections require routine visual inspection.

• Comprehensive Chain of Closed Connections (Goodfellow and Holt 2011):

  • Between the supply container and the spray tank associated with application equipment.

  • Between supply containers and any mix tank functioning as an intermediate step to application equipment spray tanks.

  • Between an intermediate mix tank (when utilized) and the application equipment spray tank.

  • Ideally, between the mix tank (or supply container) and portable spray equipment (such as backpack sprayers) receiving an application-ready formulation.

• Service Container Transfers: Service containers feature a closed connection fitting or valve for filling. However, transfer from service containers into application equipment may be performed via open pouring, as service containers generally lack closed-connection emptying mechanisms.

• Pumping Systems: Pumps operated electrically or manually may be utilized during liquid transfers, provided they are built with chemically resistant seals.

Custom Blend Formulations and Application Preferences

• Standardization vs. Flexibility: R/R supply container efficiency is maximized when a limited set of core custom mixes is standardized across utility programs. Adjustments to application-ready mixtures may be made to adapt to changing weather or site conditions.

• Application Delivery Preferences:

  • Ready-to-Use / Ready-to-Apply Custom Blends: Highly preferred for low-volume basal and cut surface herbicide applications.

  • Whole Dilute Concentrates: Highly preferred for low-volume foliar, high-volume foliar, and aerial herbicide applications.

• Paraffin Oil-Based Carriers: Formulations utilizing paraffin oil-based foliar mix carriers (such as Thinvert) serve dual roles as surfactants and drift control agents. These formulations require supplemental field agitation to maintain a uniform suspension of carrier and active ingredients.

• Stability and Shelf Life:

  • Dilute concentrate formulations supplied by blenders must demonstrate stability by presenting a uniform color without visible separation or layering.

  • Dilute concentrates must not be held in inventory longer than a single spray season, although they generally retain physical stability for up to $2\,\text{years}$.

  • Certain dry or granular herbicide formulations are physically or chemically unstable in liquid mixtures and cannot be processed into custom blends.

Field Mixing Protocols and Procedures

• On-Site Mixing Requirements:

  • Concentrates and dilute concentrates must be added to spray tanks directly on the right-of-way job site.

  • Spray equipment must be filled from supply containers directly at the job site.

  • Herbicide mixing is strictly prohibited at any location where diluent water is collected.

  • Mixing must never occur near natural water bodies; a minimum buffer distance of $100\,\text{feet}$ ($30\,\text{m}$) must be maintained from any body of water or wetland.

• Supplemental Additions:

  • Herbicide formulations that form suspensions rather than true solutions (such as dry flowables) must be added to the spray tank immediately prior to application.

  • Supplemental active ingredients introduced through an open connection must be added off the right-of-way job site (Goodfellow and Holt 2011).

• Step-by-Step Tank Mixing Sequence:

  1. Fill the spray tank half-full with the required diluent (water or oil).

  2. Add the specified concentrate or diluted concentrate to the spray tank.

  3. Add any supplemental adjuvants (e.g., surfactants, drift control agents, or other tank additives).

  4. Add the remaining volume of diluent to achieve the final target fill volume.

Service Containers vs. Disposable Packaging

• Service Container Specifications:

  • Capacity: Smaller-capacity receptacles designed to hold between $2.5$ and $5\,\text{gallons}$ (approximately $10$ to $20\,\text{liters}$).

  • Refilling Rules: Refilled directly by applicators using primary supply containers. They are restricted strictly to intra-company transport within the applicator's own operations and cannot be transferred to third parties.

  • Design Purpose: Constructed with durable materials for repeated use, service containers are sized to match application equipment capacities, eliminating the need for precise field measuring by spray crews.

• Disposable Packaging Regulations:

  • One-way disposable containers are legally marked with "do not reuse" labels.

  • It is illegal to refill or adapt single-use disposable containers for service container functions.

  • Disposable containers must be triple-rinsed immediately following single use and discarded in accordance with disposal regulations (Goodfellow and Holt 2011).

Measuring Quantities and Closed System Volume Determination

• Field Measuring Scenarios: While custom blends minimize field measurement, volumetric measuring remains necessary under two specific conditions:

  1. When a supply container holds more mixture than required for a single spray equipment fill.

  2. When the required mixture volume is less than the total capacity of the spray tank.

• Volumetric Calculations: Applicators must accurately calculate existing spray mixture volumes, accounting for both active ingredients and added diluents (water or oil).

• Measurement Protocols:

  • When supply containers exceed a $1:1$ volume ratio with the target spray tank, application-ready mixtures must be measured in full units using the supply container's graduated markings.

  • When a supply container holds less than a full standard load, the exact required volume must be measured and transferred into the spray tank.

• Spill-Reduction Measurement Equipment:

  • Cone Tanks: Intermediate fixed-volume, calibrated transfer containers that allow applicators to isolate exact mixture quantities.

  • Flow Transfer Pumps: Calibrated pumps integrated with flow meters for precise liquid metering.

  • Translucent Graduated Containers: Clear side walls on supply containers and mix/spray tanks that enable visual monitoring of liquid levels during transfer.

Inventory Management and Handling Guidelines

• Just-in-Time (JIT) Inventory Approach:

  • Balances short-term operational herbicide needs against the risks and financial costs of storing excess chemical surplus.

  • Prevents chemical waste caused by the long-term degradation of stored custom blends.

• Supply Thresholds (Goodfellow and Holt 2011):

  • Applicators should maintain no more than a $3\,\text{week}$ chemical supply on hand.

  • Programs should store no more than half ($50\%$) of the total material required for an entire program at any given time, unless the excess chemical will be fully applied within a few days.

  • Inventory must align with seasonal application goals (e.g., ordering foliar mixes during dormant seasons or holding large basal mix stocks when no basal work is scheduled is counterproductive).

• Storage and Security Protocols:

  • Herbicides must be locked inside secured storage areas inaccessible to the general public at all times, including permanent storage facilities, transit vehicles, and job sites.

  • The accumulation of partially filled supply containers must be kept to an absolute minimum.

• Care and Handling of Empty Containers:

  • Containers must strictly be returned to the original custom blender for refilling and reuse.

  • Closure integrity must be maintained; containers must not be punctured, interlocking valves must not be removed, and tamper-proof seals must remain uncompromised.

  • Turnaround Schedule: Empty containers should ideally be returned on a $30\text{-day}$ turnaround schedule, and must never exceed $60\,\text{days}$.

  • Applicators are prohibited from stockpiling empty containers to accumulate full pallet shipments before returning them (Goodfellow and Holt 2011).

Custom Blender Refilling, Testing, and Lifecycle Protocols

• Blender Responsibilities: Custom blenders hold exclusive legal responsibility for inspecting, cleaning, and refilling R/R supply containers.

• Regulatory Restrictions: Custom blenders are legally prohibited from producing dilute concentrates unless specifically ordered by a registered container owner for an explicit application purpose.

• Pressure Testing: Before refilling, custom blenders must pressure test supply containers to verify compliance with UN and DOT Class II standards.

• Container Rinsing and Cleaning Protocols:

  • Containers do not require triple-rinsing if they are refilled with the identical herbicide formulation previously contained.

  • Tanks, valves, and internal transfer hardware must undergo thorough cleaning prior to refilling with a different herbicide blend.

• Re-labeling Requirements: Every newly filled container must have its previous label completely removed and a new content-specific label applied, regardless of whether the formulation changed or stayed the same.

• Decommissioning: Upon reaching the end of its design life ($5\,\text{years}$ or $30\text{ return cycles}$), the container is thoroughly cleaned, removed from service, and recycled.

Tracking, Recordkeeping, and Digital Data Collection

• Mandatory Herbicide Application Records: Applicators are legally required to record the following data for every application:

  • Applicator identity and registration details.

  • Herbicide trade name, active ingredient(s), and official US EPA registration number.

  • Total volume/amount of herbicide applied.

  • Precise geographic location of the treatment.

  • Weather conditions present during application.

  • Total area (acres) or unit count (number of trees) treated.

• Chain of Custody Tracking: R/R supply containers are tracked through a closed chain of custody using unique identification numbers. System logs document container status as full, partial, or empty.

• Digital Field Data Capture:

  • Computerized application equipment integrates GIS mapping, GPS location tracking, timestamps, and volumetric sensors to log herbicide placement directly into databases.

  • Barcode scanners and cloud-based electronic databases automatically cross-reference container barcodes with real-time field data to generate automated application reports.

  • Field technologies continuously track environmental metrics during application, including temperature, relative humidity, wind velocity, wind direction, and precipitation.