COPY
______________________________________________________________________________________

SESD Operating Procedure Page 2 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

Revision History 

 

The top row of this table shows the most recent changes to this controlled document. For 

previous revision history information, archived versions of this document are maintained 

by the SESD Document Control Coordinator on the SESD local area network (LAN). 

History Effective Date

SESDPROC-306-R3, Wastewater Sampling, replaces 

SESDPROC-306-R2

General: Corrected any typographical, grammatical and/or editorial 

errors.

Title Page: Changed author from Liza Montalvo to Bill Simpson. 

Changed Enforcement and Investigations Branch Chief from Archie Lee 

to Danny France. Changed Field Quality Manager from Liza Montalvo to 

Bobby Lewis. 

Revision History: Changes were made to reflect the current practice of 

only including the most recent changes in the revision history. 

Section 1.2: Added the following statement: Mention of trade names or 

commercial products does not constitute endorsement or recommendation 

for use.

Section 2.2: Item 5 was revised to reflect practice of using individual 

single-use preservative vials instead of preservatives prepared by ASB.

February 28, 2013

SESDPROC-306-R2, Wastewater Sampling, replaces 

SESDPROC-306-R1

February 19, 2010

SESDPROC-306-R1, Wastewater Sampling, replaces 

SESDPROC-306-R0

November 1, 2007

SESDPROC-306-R0, Wastewater Sampling, Original Issue February 05, 2007

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 3 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

TABLE OF CONTENTS

1 General Information........................................................................................................................... 5

1.1 Purpose ............................................................................................................................................ 5

1.2 Scope/Application............................................................................................................................ 5

1.3 Documentation/Verification ........................................................................................................... 5

1.4 References ....................................................................................................................................... 5

1.5 General Precautions........................................................................................................................ 7

1.5.1 Safety .......................................................................................................................................... 7

1.5.2 Procedural Precautions ............................................................................................................. 7

2 Special Sampling Considerations....................................................................................................... 9

2.1 Special Precautions for Wastewater Sampling............................................................................... 9

2.2 Sample Handling and Preservation Requirements........................................................................ 9

2.3 Quality Control...............................................................................................................................10

2.4 Records ...........................................................................................................................................10

3 General Considerations.....................................................................................................................11

3.1 Wastewater Sampling Design....................................................................................................11

3.2 Sampling Techniques and Equipment...........................................................................................11

3.3 Site Selection for Wastewater Sampling........................................................................................12

3.3.1 Influent................................................................................................................................12

3.3.2 Effluent .................................................................................................................................13

3.3.3 Pond and Lagoon Sampling .................................................................................................13

4 Sample Types......................................................................................................................................14

4.1 General ...........................................................................................................................................14

4.2 Grab Samples .................................................................................................................................14

4.3 Composite Samples.........................................................................................................................14

5 Automatic Samplers...........................................................................................................................16

5.1 General ...........................................................................................................................................16

5.1.1 Conventional Sampling (Inorganic Parameters).....................................................................17

5.1.2 Metals ........................................................................................................................................17

5.1.3 Extractable Organic Compounds, Pesticides and PCBs..........................................................18

5.2 Automatic Sampler Security ..........................................................................................................18

5.3 Automatic Sampler Maintenance, Calibration and Quality Control............................................18

6 Manual Sampling ...............................................................................................................................20

7 Special Sample Collection Procedures.............................................................................................21

7.1 Organic Compounds and Metals...................................................................................................21

7.2 Bacteriological................................................................................................................................21

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 4 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

7.3 Immiscible Liquids/Oil and Grease ...............................................................................................21

7.4 Volatile Organic Compounds.........................................................................................................22

8 Special Process Control Samples and Tests.....................................................................................23

9 Supplementary Data Collection........................................................................................................24

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 5 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

1 General Information

1.1 Purpose

The purpose of this procedure is to document both general and specific procedures, 

methods and considerations to be used and observed when collecting wastewater samples 

for field screening or laboratory analysis.

1.2 Scope/Application

This document describes both general and specific methods to be used by field personnel 

when collecting and handling wastewater samples in the field. On the occasion that 

SESD field personnel determine that any of the procedures described in this section are 

inappropriate, inadequate or impractical and that another procedure must be used to 

obtain a wastewater sample, the variant procedure will be documented in the field log 

book, along with a description of the circumstances requiring its use. Mention of trade 

names or commercial products does not constitute endorsement or recommendation for 

use.

1.3 Documentation/Verification 

This procedure was prepared by persons deemed technically competent by SESD 

management, based on their knowledge, skills and abilities. The procedure has been 

tested in practice and reviewed in print by a subject matter expert. The official copy of 

this procedure resides on the SESD Local Area Network (LAN). The Document Control 

Coordinator is responsible for ensuring the most recent version of the procedure is placed 

on the SESD LAN and for maintaining records of review conducted prior to its issuance. 

1.4 References

California State University – Sacramento. Operation of Wastewater Treatment Plants - 

Volumes I, II, III. Sacramento, California. 

International Air Transport Authority (IATA). Dangerous Goods Regulations, Most 

Recent Version

Metcalf and Eddy, Inc. 2003. Wastewater Engineering: Treatment, Disposal, and Reuse. 

4th Edition, McGraw-Hill Book Co., New York, NY 

SESD Operating Procedure for Control of Records, SESDPROC-002, Most Recent 

Version

SESD Operating Procedure for Equipment Inventory and Management (SESDPROC104, Most Recent Version)

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 6 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

SESD Operating Procedure for Field Equipment Cleaning and Decontamination, 

SESDPROC-205, Most Recent Version 

SESD Operating Procedure for Field Equipment Cleaning and Decontamination at the 

FEC, SESDPROC-206, Most Recent Version 

SESD Operating Procedure for Field pH Measurement, SESDPROC-100, Most Recent 

Version

SESD Operating Procedure for Field Sampling Quality Control, SESDPROC-011, Most 

Recent Version

SESD Operating Procedure for Field Specific Conductance Measurement, SESDPROC101, Most Recent Version 

SESD Operating Procedure for Field Temperature Measurement, SESDPROC-102, Most 

Recent Version

SESD Operating Procedure for Logbooks, SESDPROC-010, Most Recent Version 

SESD Operating Procedure for Packaging, Marking, Labeling and Shipping of 

Environmental and Waste Samples, SESDPROC-209, Most Recent Version 

SESD Operating Procedure for Sample and Evidence Management, SESDPROC-005, 

Most Recent Version

SESD Operating Procedure for Surface Water Sampling (SESDPROC-201), Most Recent 

Version

SESD Operating Procedure for Wastewater Flow Measurement, SESDPROC-109, Most

Recent Version

Title 40 Code of Federal Regulations (CFR), Part 136.3, Table II, Most Recent Version 

US EPA. 1977. Process Control Manual: Aerobic Biological Treatment Facilities MD-14. 

EPA 430/09-77-006, Office of Water, Washington, D.C. 

US EPA. 2000. Activated Sludge Process Control Testing. ESD, Water Compliance Unit, 

Athens, GA 

US EPA. 2001. Environmental Investigations Standard Operating Procedures and Quality 

Assurance Manual. Region 4 Science and Ecosystem Support Division (SESD), Athens, 

GA

US EPA. 2004. National Pollutant Discharge Elimination System (NPDES) Compliance 

Inspection Manual 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 7 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

US EPA. Analytical Support Branch Laboratory Operations and Quality Assurance 

Manual. Region 4 SESD, Athens, GA, Most Recent Version 

US EPA. April 13, 1981. Final Regulation Package for Compliance with DOT 

Regulations in the Shipment of Environmental Laboratory Samples. Memo from David 

Weitzman, Work Group Chairman, Office of Occupational Health and Safety (PM-273) 

US EPA. Safety, Health and Environmental Management Program Procedures and Policy 

Manual. Region 4 SESD, Athens, GA, Most Recent Version 

Water Environment Federation and ASCE. 1998. Design of Municipal Wastewater 

Treatment Plants. Manual of Practice No. 8, Fourth Edition. 

Water Environment Federation. 1996. Operation of Municipal Wastewater Treatment 

Plants. Manual of Practice No.11, Fifth Edition 

1.5 General Precautions

1.5.1 Safety

Proper safety precautions must be observed when collecting wastewater samples. 

Refer to the SESD Safety, Health and Environmental Management Program 

Procedures and Policy Manual and any pertinent site-specific Health and Safety 

Plans (HASP) for guidelines on safety precautions. These guidelines, however, 

should only be used to complement the judgment of an experienced professional. 

Address chemicals that pose specific toxicity or safety concerns and follow any 

other relevant requirements, as appropriate.

1.5.2 Procedural Precautions

The following precautions should be considered when collecting wastewater

samples.

• Special care must be taken not to contaminate samples. This includes storing 

samples in a secure location to preclude conditions which could alter the 

properties of the sample. Samples shall be custody sealed during long-term 

storage or shipment. 

• Collected samples are in the custody of the sampler or sample custodian until 

the samples are relinquished to another party. 

• If samples are transported by the sampler, they will remain under his/her 

custody or be secured until they are relinquished. 

• Shipped samples shall conform to all U.S. Department of Transportation 

(DOT) and/or International Air Transportation Association (IATA) hazardous 

materials shipping requirements.

• Documentation of field sampling is done in a bound logbook. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 8 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

• Chain-of-custody documents shall be filled out and remain with the samples 

until custody is relinquished. 

• All shipping documents, such as air bills, bills of lading, etc., shall be retained 

by the project leader and stored in a secure place.

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 9 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

2 Special Sampling Considerations

2.1 Special Precautions for Wastewater Sampling

• A clean pair of new, non-powdered, disposable gloves will be worn each time a 

different location is sampled and the gloves should be donned immediately prior 

to sampling. The gloves should not come in contact with the media being 

sampled and should be changed any time during sample collection when their 

cleanliness is compromised.

• Sample containers for samples suspected of containing high concentrations of 

contaminants shall be stored separately.

• Sample collection activities shall proceed progressively from the least suspected 

contaminated area to the most suspected contaminated area. Samples of waste or 

highly contaminated media must not be placed in the same ice chest as 

environmental (i.e., containing low contaminant levels) or background/control 

samples.

• If possible, one member of the field sampling team should take all the notes and 

photographs, fill out tags, etc., while the other members collect the samples.

• Field investigators must use new, verified certified-clean disposable or nondisposable equipment cleaned according to procedures contained in SESD 

Operating Procedure for Field Equipment Cleaning and Decontamination 

(SESDPROC-205) for collection of samples for trace metals or organic compound

analyses. 

2.2 Sample Handling and Preservation Requirements

1. All sample collection and preservation procedures will comply with the 

requirements outlined in 40 CFR, Part 136.3 (e), Table II, and Figure 3-1 of the 

US EPA Region 4 Analytical Support Branch Laboratory Operations and Quality 

Assurance Manual (ASBLOQAM), Most Recent Version.

2. Wastewater samples will typically be collected either by directly filling the 

sample container or by using an automatic sampler or other device. 

3. During sample collection, if transferring the sample from a collection device, 

make sure that the device does not come in contact with the sample containers. 

4. Place the sample into appropriate, labeled containers. Samples collected for VOC 

analysis must not have any headspace (see Section 7.4, Volatile Organic 

Compounds). All other sample containers must be filled with an allowance for 

ullage.

5. All samples requiring preservation must be preserved as soon as practically 

possible, ideally immediately at the time of sample collection. If preserved VOC 

vials are used, these will be preserved with concentrated hydrochloric acid by 

Analytical Support Branch (ASB) personnel prior to departure for the field 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 10 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

investigation. For all other chemical preservatives, SESD will use the appropriate 

chemical preservative generally stored in an individual single-use vial as 

described in the SESD Operating Procedure for Field Sampling Quality Control 

(SESDPROC-011). The adequacy of sample preservation will be checked after 

the addition of the preservative for all samples, except for the samples collected 

for VOC analysis. If it is determined that a sample is not adequately preserved, 

additional preservative should be added to achieve adequate preservation. 

6. All samples preserved using a pH adjustment (except VOCs) must be checked, 

using pH strips, to ensure that they were adequately preserved. This is done by 

pouring a small volume of sample over the strip. Do not place the strip in the 

sample. Samples requiring reduced temperature storage should be placed on ice 

immediately.

 

2.3 Quality Control 

Equipment blanks should be collected if equipment is field cleaned and re-used on-site or 

if necessary to document that low-level contaminants were not introduced by the 

sampling equipment. 

2.4 Records

Information generated or obtained by SESD personnel will be organized and accounted 

for in accordance with SESD records management procedures found in the SESD 

Operating Procedure for Control of Records (SESDPROC-002). Field notes, recorded in 

a bound field logbook, will be generated, as well as chain-of-custody documentation 

according to the procedures found in SESD Operating Procedure for Logbooks 

(SESDPROC-010) and SESD Operating Procedure for Sample and Evidence 

Management (SESDPROC-005). 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 11 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

3 General Considerations 

3.1 Wastewater Sampling Design 

Wastewater sampling studies focus primarily on collecting wastewater samples of the 

influent or effluent at domestic and non-domestic facilities. Sampling activities are 

usually conducted for National Pollutant Discharge Elimination System (NPDES) 

compliance, compliance assistance, civil and criminal investigations, and water quality 

studies. Collection of wastewater samples is necessary in order to obtain reliable data that 

can support compliance or enforcement activities. 

The main considerations in developing a wastewater sampling strategy are:

• Type of study (Compliance Sampling Inspection, Diagnostic Evaluation, etc.). 

• Regulated or target pollutants in the wastewater stream to be sampled.

• Selection of the projected sampling locations to satisfy the study objectives. 

• Quality control criteria of the parameters to be sampled (oil and grease samples 

need to be collected as grab samples, trip blanks are taken into the field for the 

collection of samples for volatile organic compound analyses, etc.). 

Complexity of the sampling program will vary with a number of factors. Some primary 

factors are:

• The number of sampling stations to be monitored. This will be dependent on 

NPDES permit requirements and the type of study (typically Toxic CSIs and DEs 

require a greater amount of sampling stations than a routine CSI).

• Special handling requirements of the target pollutants (sampling equipment for 

trace organic compounds require special cleaning procedures, etc.). 

• Laboratory conducting the analyses (use of a contract laboratory may require 

shipping from the field, etc.). 

• Accessibility to sampling stations.

• Process and operation criteria of the source generator (e.g., batch operation versus 

continuous discharge).

• Coordination of participating organizations in the study (e.g., state assistance with 

the sample collection). 

• The length of time for sampling activities will dictate logistical considerations 

(e.g., shipment of samples, additional supplies, etc.). 

3.2 Sampling Techniques and Equipment

The wastewater sampling techniques and equipment described in Sections 4 through 9 of 

this document are designed to minimize effects on the chemical and physical integrity of 

the sample. If the procedures in these sections are followed, a representative sample of 

the wastewater should be obtained. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 12 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

The variety of conditions at different sampling locations requires that considerable 

judgment be exercised regarding the methodologies and procedures for the collection of 

representative samples of wastewater. Each sampling location warrants attention 

commensurate with its complexity. There are, however, basic rules and precautions 

generally applicable to sample collection. Acceptable procedures are generally those 

outlined in the NPDES Compliance Inspection Manual. Some important considerations 

for obtaining a representative wastewater sample include:

• The sample should be collected where the wastewater is well mixed. Therefore, 

the sample should be collected near the center of the flow channel, at 

approximately 40 to 60 percent of the water depth, where the turbulence is at a 

maximum and the possibility of solids settling is minimized. Skimming the water 

surface or dragging the channel bottom should be avoided. However, allowances 

should be made for fluctuations in water depth due to flow variations. 

• In sampling from wide conduits, cross-sectional sampling should be 

considered. Rhodamine WT dye may be used as an aid in determining the most 

representative sampling locations.

• If manual compositing is employed, the individual sample portions must be 

thoroughly mixed before pouring the individual aliquots into the composite 

container. For manual composite sampling, the individual sample aliquots should 

be preserved at the time of sample collection. 

3.3 Site Selection for Wastewater Sampling 

Where applicable, wastewater samples should be collected at the location specified in the 

NPDES permit (if the source has a permit). In some instances the sampling location 

specified in the permit, or the location chosen by the permittee, may not be adequate for 

the collection of a representative wastewater sample. In such instances, the investigator 

is not limited by permit specifications and may collect a sample at a more representative 

location. When a conflict exists between the permittee and the regulatory agency

regarding the most representative sampling location, both sites should be sampled, and 

the reason for the conflict should be noted in the field notes and the inspection or study 

report. Recommendations and reasons for a change in sampling locations should be 

given to the appropriate permitting authority. 

3.3.1 Influent

Influent wastewaters are preferably sampled at locations of highly turbulent flow 

in order to ensure good mixing; however, in many instances the most desirable 

location is not accessible. Preferable influent wastewater sampling locations 

include: 1) the upflow siphon following a comminutor (in absence of grit 

chamber); 2) the upflow distribution box following pumping from main plant wet 

well; 3) aerated grit chamber; 4) flume throat; 5) pump wet well when the pump is 

operating; or 6) downstream of preliminary screening. When possible, influent 

samples should be collected upstream from sidestream returns. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 13 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

3.3.2 Effluent

Effluent samples should be collected at the site specified in the permit, or if no 

site is specified in the permit, at the most representative site downstream from all 

entering wastewater streams prior to discharge into the receiving waters. If a 

conflict exists between the permittee and inspector regarding the source being 

sampled or the location of the most representative site, follow the procedures 

previously described in Section 3.3, Site Selection for Wastewater Sampling. 

 3.3.3 Pond and Lagoon Sampling 

Generally, composite effluent wastewater samples should be collected from ponds 

and lagoons. Even if the ponds or lagoons have long retention times, composite 

sampling is necessary because of the tendency of ponds and lagoons to have flow 

paths that short circuit which changes the design detention time.

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 14 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

4 Sample Types

4.1 General

For NPDES sampling, two types of sampling techniques are used: grab and composite. 

For these procedures, the NPDES permit specifies the appropriate sample type. A 

complete description of all NPDES sampling procedures and techniques is presented in 

the NPDES Compliance Inspection Manual. 

4.2 Grab Samples

Grab samples consist of either a single discrete sample or individual samples collected 

over a period of time not to exceed 15 minutes. The grab sample should be 

representative of the wastewater conditions at the time of sample collection. The sample 

volume depends on the type and number of analyses to be performed. 

4.3 Composite Samples 

Composite samples are collected over time, either by continuous sampling or by mixing 

discrete samples. A composite sample represents the average wastewater characteristics 

during the compositing period. Various methods for compositing are available and are 

based on either time or flow proportioning. The choice of a flow proportional or time 

composite sampling scheme depends on the permit requirements, variability of the 

wastewater flow or concentration of pollutants, equipment availability and sampling 

location. The investigator must know each of these criteria before a sampling program 

can be initiated. Generally, a time composite is acceptable. However, in enforcement 

cases where strict adherence to permit requirements are necessary, a flow proportional 

sample is preferable, if possible. 

A time composite sample consists of equal volume discrete sample aliquots collected at 

constant time intervals into one container. A time composite sample can be collected 

either manually or with an automatic sampler. 

A flow proportional composite sample can be collected using one of two methods. One 

method consists of collecting a constant sample volume at varying time intervals 

proportional to the wastewater flow. For the other method, the sample is collected by 

varying the volume of each individual aliquot proportional to the flow, while maintaining 

a constant time interval between the aliquots. 

Flow proportional samples can be collected directly with an automatic sampler that is 

connected to a compatible flow measuring device. An automatic sampler can also be used 

to collect discrete samples. At the end of the compositing period, the discrete samples 

are composited by volume versus flow chart readings. Field personnel can use the 

facility’s primary flow device and flow measurement system when their accuracy can be 

verified. Prior to collecting flow proportional samples, the facility’s flow measuring 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 15 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

system should be examined for proper installation and accuracy according to SESD 

Operating Procedure for Wastewater Flow Measurement (SESDPROC-109). If the 

facility’s primary flow measuring device does not meet standard conditions specified in 

SESDPROC-109 (Most Recent Version), or is in an unsafe or inaccessible location, then 

the investigator may choose to collect time composite samples or install a portable 

primary flow device. If the flow measurement system is acceptable, samples should be 

collected using the appropriate flow proportioning methods. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 16 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

5 Automatic Samplers

5.1 General

Automatic samplers may be used to collect composite or grab samples when several 

aliquots are to be collected at frequent intervals or when a continuous sample is required. 

For composite sampling applications, the automatic samplers may be used to collect time 

composite or flow proportional samples. In the flow proportional mode, the samplers are 

activated and paced by a compatible flow meter. Flow proportional samples can also be 

collected using an automatic sampler equipped with multiple containers and manually 

compositing the individual sample portions proportional to the flow. 

Automatic samplers must meet the following requirements: 

• Sampling equipment must be properly cleaned to avoid cross-contamination which 

could result from prior use per the SESD Operating Procedure for Field Equipment 

Cleaning and Decontamination (SESDPROC-205).

• No plastic or metal parts of the sampler shall come in contact with the water or 

wastewater stream when parameters to be analyzed could be impacted by these 

materials.

• The automatic sampler must be capable of providing adequate refrigeration during the 

sampling period. This can be accomplished in the field by using ice. 

• The automatic sampler must be able to collect a large enough sample for all 

parameter analyses. 

• The individual sample aliquot must be at least 100 ml if the sampler uses a peristaltic 

pump. 

• The automatic sampler should be capable of providing a lift of at least 20 feet and the 

sample volume should be adjustable since the volume is a function of the pumping 

head.

• The pumping velocity must be at least 2 ft/sec to transport solids and not allow solids 

to settle.

• The intake line leading to the pump must be purged before each sample is collected. 

• The minimum inside diameter of the intake line should be 1/4 inch. 

• An adequate power source should be available to operate the sampler for the time 

required to complete the project. Facility electrical outlets may be used if available. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 17 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

• Facility automatic samplers should only be used if 1) field conditions do not allow for 

the installation of EPA sampling equipment, and 2) the facility sampling equipment 

meets all of the requirements detailed above.

 

Specific operating instructions, capabilities, capacities, and other pertinent information 

for automatic samplers are included in the respective operating manuals. 

5.1.1 Conventional Sampling (Inorganic Parameters)

Conventional sampling includes all inorganic parameters (e.g., BOD5, TSS, COD, 

nutrients) that can be collected using an automatic sampler. 

New tubing (Silastic7, or equal, in the pump and either Teflon7 or Tygon7, or 

equal, in the sample train) will be used for each sampler installation. 

Installation procedures include cutting the proper length of tubing, positioning it 

in the wastewater stream, and sampler programming. Protective gloves should be 

worn to reduce exposure and to maintain the integrity of the sample. 

For a time composite sample, the sampler should be programmed to collect 

sufficiently sized aliquots (at least 100-milliliter if using a peristaltic pump) at a 

frequency that provides a representative sample and enough sample volume to 

conduct all required analyses. 

For a flow proportional sample, the sampler should be programmed to collect a 

minimum of 100 milliliters for each sample aliquot with the interval 

predetermined based on the flow of the monitored stream. 

At the end of the compositing period, the sample collected should be properly 

mixed and transferred into the respective containers, followed by immediate 

preservation, if required. For routine inspections, the permittee should be offered 

a split sample. 

5.1.2 Metals

When an automatic sampler is used for collecting samples for metals analyses, the 

entire sample collection system should be rinsed with organic-free water and an 

equipment blank should be collected. Approximately one-half gallon of rinse 

water should be pumped through the sample tubing into the composite container 

and discarded. Nitric acid must be added to the metals blank container for proper 

preservation. The sampler may then be positioned in the appropriate location and 

the sampler program initiated.

If the automatic sampler tubing is attached to a metal conduit pipe, the intake 

tubing should be carefully installed upstream and away from the conduit to 

prevent metals contamination. This can be accomplished by clamping the tubing 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 18 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

upstream of the conduit using laboratory clamps and wrapping the submerged 

portion of conduit pipe with a protective barrier (e.g., duct tape). 

5.1.3 Extractable Organic Compounds, Pesticides and PCBs

When an automatic sampler is used for collecting samples for the analyses of 

extractable organic compounds, pesticides and/or PCBs, the installation 

procedures include cutting the proper length of new Teflon7 tubing, rinsing of the 

entire sampler collection system with organic-free water and collection of 

appropriate equipment blanks for organic compounds analysis. For the organicfree water rinse, approximately one-half gallons is initially pumped into the 

composite sample container and discarded. An additional one and one-half 

gallons (approximate) are then pumped into the composite sample container for 

distribution into the appropriate blank container. Finally, the collection tubing 

should be positioned in the wastewater stream and the sampler programmed and 

initiated.

5.2 Automatic Sampler Security

Field investigators should take whatever steps are necessary to prevent tampering with 

EPA equipment. A lock or custody seal may be placed on the sampler to detect 

tampering. However, this does not prevent tampering with the sample collection tubing. 

If necessary, seals may be placed on the sampling pole and tubing line to further reduce 

tampering possibilities.

5.3 Automatic Sampler Maintenance, Calibration and Quality Control

To ensure proper operation of automatic samplers, and thus the collection of representative samples, the following maintenance and calibration procedures should be 

used and any deviations should be documented in the field logbook. 

Prior to being used, the sampler operation should be checked by the field investigator or 

Field Equipment Center personnel to ensure proper operation. This includes operation 

(forward, reverse, and automatic) of at least one purge-pump-purge cycle; checking 

desiccant and replacing if necessary; checking the 12-volt batteries to be used with the 

sampler; and repairing any item if necessary.

During each field trip, prior to initiating the automatic sampler, the rinse and purgepump-purge cycle shall be checked at least once. The pumping volume should be 

checked at least twice using a graduated cylinder or other calibrated container prior to 

initiating the sampler. For flow proportional sampling, the flow meter that activates the 

sampler should be checked to ensure that it operates properly. 

Upon returning from a field trip, the structural integrity of the sampler should be 

examined and repaired, if necessary. The desiccant will be checked and replaced if 

appropriate. The operation (forward, reverse, automatic, etc.) will be checked and 

required repairs will be made and documented. The sampler will then be cleaned as 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 19 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

outlined in SESD Operating Procedures for Field Equipment Cleaning and 

Decontamination (SESDPROC-205). 

The automatic sampler should be checked against the manufacturer's specifications and 

documented whenever one or more of the sampler functions appear to be operating 

improperly. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 20 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

6 Manual Sampling

Manual sampling is normally used for collecting grab samples and/or for immediate insitu field analyses. However, it can also be used in lieu of automatic equipment over 

extended periods of time for composite sampling, especially when it is necessary to 

evaluate unusual waste stream conditions. 

The best method to manually collect a sample is to use the actual sample container which 

will be used to transport the sample to the laboratory. This eliminates the possibility of 

contaminating the sample with intermediate collection containers. If the water or 

wastewater stream cannot be physically reached by the sampling personnel or it is not 

safe to reach for the sample, an intermediate collection container may be used, from 

which the sample can be redistributed to other containers. If this is done, however, the 

container used to collect the sample must be properly cleaned according to the SESD 

Operating Procedure for Field Equipment Cleaning and Decontamination (SESDPROC205) and must be made of a material that meets the requirements of the parameter(s) 

being investigated. Samples for oil and grease, bacteria, and most volatile compounds 

(both organic and inorganic; see Section 7.4 for specific requirements) must always be 

collected directly into the sample container.

In some cases it may be best to use a pump, either power or hand operated, to withdraw a 

sample from the water or wastewater stream. If a pump is used, it is imperative that all 

components of the pump that come in contact with the sample are properly cleaned 

according to the SESD Operating Procedure for Field Equipment Cleaning and 

Decontamination (SESDPROC-205) to ensure the integrity of the sample. 

In general, samples are manually collected by first selecting a location in the wastestream

that is well mixed then dipping the container in the water or wastewater stream so the 

mouth of the container faces upstream. The container should not be overfilled if 

preservatives are present in the container.

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 21 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

7 Special Sample Collection Procedures 

7.1 Organic Compounds and Metals

Trace organic compounds and metals detection limits are usually in the parts per billion 

or parts per trillion ranges, so extreme care must be exercised to ensure sample integrity.

All containers, composite bottles, tubing, etc, used for sample collection for trace organic 

compounds and metals analyses should be prepared as described in the SESD Standard 

Operating Procedure for Field Equipment Cleaning and Decontamination at the FEC 

(SESDPROC-206). 

When possible, the sample should be collected directly into the appropriate sample 

container. If the material to be sampled cannot be physically reached, an intermediate 

collection device may be used. This should be a Teflon7, glass or stainless steel (for nonmetals only) vessel on a pole or rope, or Teflon7 tubing via a peristaltic type pump and a 

Teflon7 vacuum container attachment which converts a sample container into a vacuum 

container. The device which is used should be cleaned as described in the SESD 

Operating Procedure for Field Equipment Cleaning and Decontamination (SESDPROC205). 

Sample collection for trace-level mercury analysis will be conducted in accordance with 

the SESD Operating Procedure for Surface Water Sampling (SESDPROC-201). This 

procedure is based on EPA Method 1669. 

7.2 Bacteriological 

Samples for bacteriological analyses must always be collected directly into the prepared 

glass or plastic sample container. The sample container should be kept unopened until it 

is to be filled. When the cap is removed, care should be taken not to contaminate the cap 

or the inside of the bottle. The bottle should be held near the base and filled to within 

about one inch of the top without rinsing and recapped immediately. During sample 

collection, the sample container should be plunged with the neck partially below the 

surface and slightly upward. The mouth should be directed against the current. 

Preservation procedures and holding times are found in the ASBLOQAM. 

When the sample container must be lowered into the waste stream, either because of 

safety or impracticality (manhole, slippery effluent area, etc.), care must be taken to 

avoid contamination. 

7.3 Immiscible Liquids/Oil and Grease

Oil and grease may be present in wastewater as a surface film, an emulsion, a solution or 

as a combination of these forms. Since it is very difficult to collect a representative 

sample for oil and grease analysis, the inspector must carefully evaluate the location of 

the sampling location. The most desirable sampling location is the area of greatest 

mixing. Quiescent areas should be avoided. The sample container should be plunged 

into the wastewater using a swooping motion with the mouth facing upstream. Care 

should be taken to ensure that the bottle does not over fill during sample collection. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 22 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

Because losses of oil and grease will occur on sampling equipment, an automatic sampler 

should not be used to collect samples for oil and grease analysis. Individual portions 

collected at prescribed time intervals must be analyzed separately to obtain the average 

concentrations over an extended period. 

7.4 Volatile Organic Compounds 

Samples to be analyzed for volatile organic compounds (VOCs) should be collected in 

40-ml septum vials with screw caps with a Teflon7-lined silicone disk (septum) in the cap 

to prevent contamination of the sample by the cap. Samples for VOC analysis must be 

collected using either stainless steel or Teflon® equipment.

When sampling for VOCs, triplicate samples should always be collected from each 

location. The investigator should determine if the water to be sampled contains chlorine. 

If the water contains no chlorine, three pre-preserved 40-ml vials should be filled with the 

sample. The samples may be held for up to 14 days before analysis. When preservation 

is not feasible, samples can be held up to 7 days before analysis. In the great majority of 

cases, the preserved vials are used to take advantage of the extended holding time. In 

some situations, however, it may be necessary to use the unpreserved vials. For example, 

if the wastewater sample contains a high concentration of dissolved calcium carbonate, 

there may be an effervescent reaction between the hydrochloric acid and the water, 

producing large numbers of fine bubbles. This will render the sample unacceptable. In 

this case, unpreserved vials should be used and arrangements must be confirmed with the 

laboratory to ensure that they can accept the unpreserved vials and meet the shorter 

sample holding times.

If the water contains chlorine, collect the sample in an 8-ounce sampling container with 2 

drops of a 25% ascorbic acid solution (the jar with acid should be obtained from the 

SESD laboratory prior to sample collection). Cap and mix thoroughly but gently by 

swirling to eliminate residual chlorine. Transfer the sample to three pre-preserved 40-ml 

vials. The ascorbic acid and preservative must be added in this order and in two separate 

steps. 

The 40-ml vials should be completely filled to prevent volatilization, and extreme caution 

should be exercised when filling each vial to prevent any turbulence which could also 

produce volatilization. The sample should be carefully poured down the side of the vial 

to minimize turbulence. As a rule, it is best to gently pour the last few drops into the vial 

so that surface tension holds the water in a "convex meniscus." The cap is then applied 

and some overflow is lost, but air space in the bottle is eliminated. After capping, turn 

the bottle over and tap it to check for bubbles. If a bubble or bubbles are present, the vial 

should be topped off using a minimal amount of sample to re-establish the meniscus. 

Care should be taken not to flush any preservative out of the vial during topping off. If, 

after topping off and capping the vial, bubbles are still present, a new vial should be 

obtained and the sample re-collected.

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 23 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

8 Special Process Control Samples and Tests

During diagnostic evaluations, process control tests may be conducted to evaluate and 

troubleshoot the performance of the biological treatment processes of a municipal or 

industrial wastewater treatment facility. The EPA Activated Sludge Process Control 

Manual is the standard reference used by EPA inspectors for activated sludge process 

control testing. The manual includes a complete description of the step-by-step 

procedures for each test and the interpretation of the results. The six basic activated 

sludge process control tests are:

• Sludge settleability (settlometer)

• Centrifuge spins 

• Aeration basin Dissolved Oxygen (DO) profiles

• Oxygen uptake rate (OUR) measurements

• Mixed liquor microscopic examinations 

• Sludge blanket depth (SBD) measurements

Additional references are available that provide a more comprehensive evaluation of the 

methods used to conduct a diagnostic evaluation. 

COPY
______________________________________________________________________________________

SESD Operating Procedure Page 24 of 24 SESDPROC-306-R3 

Wastewater Sampling Wastewater Sampling(306)_AF.R3 

 

Effective Date: February 28, 2013 

9 Supplementary Data Collection

While conducting wastewater sampling, the following information will also be obtained 

(if applicable):

• Field measurements -- pH, dissolved oxygen, total residual chlorine, conductivity 

and temperature 

• Flows associated with the samples collected -- continuous flows with composite 

samples and instantaneous flows with grab samples 

• Diagrams and/or written descriptions of the wastewater treatment systems (if 

available).

• Photographs of pertinent wastewater associated equipment, such as flow 

measuring devices, treatment units, etc. (keep photolog as specified in the SESD 

Operating Procedure for Logbooks (SESDPROC-010)). 

• Process control information on the wastewater treatment process (if applicable). 

• Completion of applicable forms required during specific investigations. 

All observations, measurements, diagrams, etc., will be entered in bound field logbooks 

or as specified in the SESD Operating Procedure for Logbooks (SESDPROC-010). 

COPY