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Influent and Effluent Sampling at Wastewater Facilities  

Note: These sampling procedures are provided assuming that extractable organics, and/or volatile organic compound samples will not be collected. See DEP - SOP-001/01 FS 2400  for specific requirements for organic samples.

• Obtain the sampling kit containing the bottles, chain of custody forms and additional preservatives from the laboratory.
  

• Gather sampling equipment. The equipment can be made of plastic, glass, teflon, or stainless steel.
  

• Before sample collection clean all sampling equipment with a brush using hot water and Liquinox soap. Rinse thoroughly with tap water three to four times. Rinse with a 10-15% reagent grade hydrochloric acid. Do not use a nitric acid rinse if analyzing for nitrate or nitrogen compounds. Stainless steel equipment should not be rinsed in acid. Use analyte free water for the final rinse [most commonly used is de-ionized (DI) water]. An alcohol rinse is not necessary. DO NOT USE BLEACH FOR CLEANING PURPOSES.
  

• Disposable unpowdered gloves are recommended for sample collection to protect personnel who collect the samples and to assure the integrity of the samples. Disposable gloves should be changed at each sampling location.
  

• Determine the correct location for sample collection. This is usually described in the permit for the facility. If there are questions about a representative sampling location, please contact the wastewater compliance section at the local Department of Environmental Protection office.
  

• Grab samples should be collected directly into the sample bottles whenever possible, particularly for fecal coliform. NOTE: Bottles with preservatives are the exception (see below).  Collect the sample directly into the unpreserved container by submerging the container, top first, into the effluent. Point top of the bottle into the flow. After filling, pour out a few milliliters of sample to allow for air space for expansion, sample preservation, and mixing.
  

• If access to the sampling location is restricted, secure the bottle to a pole using a clip or other device and collect the sample directly into the bottle.
  

• Fecal coliform sample collection requires extra care. Make sure that sodium thiosulfate pill is not lost during sample collection.
  

• If collection directly into the bottle is not possible, an intermediate container may be used. The container must be thoroughly cleaned using the same procedures as for other sampling equipment. The container must be rinsed several times in the sample water. If the container is used for more than one sampling location and no metals and/or organics are being sampled, the container should be rinsed with tap water between sampling points. At the next sampling location rinse the container several times in the sample water.
  

• Bottles with preservatives should be filled from an intermediate container so none of the preservative will be lost.
  

• Preservatives should be checked with narrow range pH paper to confirm that the samples are correctly preserved. Shake bottle thoroughly before performing the pH check. Do not dip the pH paper directly into the sampling container. Sample water may be poured directly onto the pH paper or a small amount of the sample can be poured into another container to check the pH. The small amount of the sample should be discarded after checking the pH.
  

• Keep the samples packed on ice for delivery to the laboratory.

  AUTOMATIC SAMPLERS

• Obtain the sampling kit containing the bottles, chain of custody forms and additional preservatives from the laboratory.
  

• The exterior and accessible interior portions of the automatic sampler should be washed with Liquinox soap and rinsed with tap water.
  

• All tubing should be visually checked. Tubing that has become discolored or has lost its elasticity should be changed. New pump tubing should be installed.
  

• Disposable unpowdered gloves are recommended for assembly of the unit at the sampling location and for dis-assembly to protect personnel who collect the samples and to assure the integrity of the samples. Disposable gloves should be changed at each sampling location.
  

• Check the permit for the facility to determine if samples are to be collected according to time or flow proportioned composite samples.
  

• A minimum of 100 milliliters should be collected each time the unit activates.
  

• Pack ice inside and around the sampler or set refrigerated units to 4 degrees Celsius.
  

• Collection line tubing should not be resting on the bottom or against the walls of the tank. Place the tubing in the turbulent zone. For influent samples, return sludge or other influences should not affect the sample.
  

• Check the timing and delivery of the automatic sampler by setting the unit for start up a few minutes later and use a graduated cylinder to measure the amount collected.
  

• For both influent and effluent samples, the automatic sampler purges the line each time samples are collected. Make sure the line does not contain any low areas where residuals would be retained in the line between sample collections.

For additional information please see DEP 's  Standard Operating Procedures 001/01 or visit web site: 
  http://www.dep.state.fl.us/labs/qa/sops.htm

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Central District

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