The heart and soul of the Composite Sampler is the computer control pad and the pump housing. The control pad allows for a variety of sampling options based on flow or time. The controller in turn tells the pump when to take a sample. When the pump is activated, it first runs backwards to purge the sample line of any remaining sample. Then the pump will take a sample and deposit it into one of the bottle configuration shown below. After the sample is taken, the pump again runs backwards to purge the line again. The sample is pulled through the sample tubing and strainer shown sitting in front of the sampler. The strainer is the narrow silver object at the bottom of the picture. The strainer is used to hold the tubing in place on the bottom of the pipe and has holes drill around it to allow the sample to pass through.
In the case of flow proportional sampling, a sample is taken every X number of gallons of flow. The amount of flow between samples can be changed for each location. Some form of flow metering device is needed for this operation.
The other set up is for time based samples. Here the sampler is programmed to take a sample every X minutes. The interval between samples can range from 1 to 9999 minutes.
Here the base of the sampler has a dedicated 10 liter (2.5gal) container that is used to collect the samples that are taken over the period of sampling. This set up is called a sequential composite sample and it used for most of all routine composite samples for flow or timed based. Each sample location within the City has its own sample bottle to eliminate any possible cross contamination from other sample points. All bottles, tubing and samplers are cleaned at the office in accordance with FDEP Standard Operation Procedures for Cleaning and Decontamination. Periodic samples are collected through the cleaned equipment and sent to the Wastewater Laboratory to ensure that no contamination is present.
In this set up, 24-1 liter bottles are used. This set up is used for tracking different discharges characteristics over a sampling period. Usually the controller is programmed to take a sample every 15 minutes and put 4 samples into a single bottle before advancing to the next bottle. When the sampling is completed, you have a sample for every hour of the sampling period so that trends can be detected. This set up is used for mainly for investigative work or for assisting an industrial customer with discharge patterns.