Sampling

Groundwater Sampling

By: Tim Young - Waukesha WWTP

Our pretreatment department found it cost effective to perform the City of Waukesha's required groundwater monitoring themselves. The photos to the left and below show their setup. Nothing super fancy as sampling is only performed two times per year.

On the cart is the sampling pump and test equipment. Two five-gallon pails are calibrated so well purge volumes can be determined. Each well has a sample bottle caddy with the bottles already labeled for the respective well.

The photo below shows the generator that runs the sample pump.

Each well is first measured for groundwater depth. The pump is inserted into the well and the required water volume is purged. Then a valve is opened to the flow through sample cell where probes for dissolved oxygen, redox, and pH are located. A conductivity meter is also used, but it is not in the cell.

• All sample lines are Teflon lined polyethylene hose.
• Well sample water is filtered through a1.0 micron glass prefilter, then a 0.45 micron filter placed back-to-back in the filter holder.
• The pump hose that is inserted into the well is marked off in feet so it is easy to find the proper depth to place the pump within the well.
• To find flow through samplers, input "flow through sample cell" in your favorite search engine. The one pictured is from Solinst.

Manhole Holder for a Portable Sampler

By: Ron Altmann

The manhole sampler holders sold in catalogs are very expensive. This holder was made from stainless steel left over from our recent plant construction. Even the flat stock was cut from a damaged electrical cabinet. The only cost was the threaded rod and nuts.

It was constructed by welding the "cross" section from pipe. To make the holder adjustable, nuts were welded to the four ends and five inches of threaded rod was welded to the flat stock which was bent to fit the manhole lip. To hold the flat stock in place, jam nuts are used to lock them in position. The jam nuts also have a larger diameter pipe welded to them to more easily turn them by hand.

Permanent Manhole Cover Lifter

By: Ron Altmann

This device eliminates the need to locate a lifting tool for a manhole cover and is particularly useful for a cover that's frequently opened. I used a plasma torch to cut a hole through the cover and gouged a recess to allow the lifter to lay flat on the surface. A piece of flat stock is welded to a rod for the handle. The rod is placed through the hole and another piece of flat stock is welded to the other end securing it into place.

Note how this manhole is on grass. I would be cautious of using this over an area that's snow plowed. If the device did stick up and wouldn't go back into position, damage to the plow or manhole could result.

Pictured is Matt Kube (deer hunter extraordinaire) using the device.

Pretreatment Sampling

By: Tim Young - Waukesha WWTP

The pretreatment van is parked just ahead of the sampling manhole. Flashers are turned on and cones are placed for traffic control. In the middle right side of the photo you see the manhole cover cracked open on the downwind side for air quality sampling.

A long handled brush is used from the surface to clean debris from the flume. Brush and pole are from Grainger.

The brush is removed from the pole and a staff gauge is attached. It is used to stick the water depth. A cork backing shows the water level. Cork-backed rulers can also be velcroed to front of gauge for taking multiple readings. Staff gauge is from USA Bluebook.

The airline was previously fitted with a quick disconnect. The lower insert photo shows a stainless pin taped to the airline that weighs it down in the flume. Quick disconnects are from McMaster.

The flow meter is lowered into the manhole suspended from a rope. The rope is attached to the top rung of the manhole ladder.

The airline is taped off in a loop. The loop is placed over a masonry nail at the top of the manhole to keep tubing from being washed down the channel.

The pole is used to position the air line and sampler strainer.

The sampler is lowered into the manhole with an old outdated confined space fall protection tripod. It is then suspended from a manhole crossbar sampler hanger.

The sampler hanger can be made (see on this site) or purchased through ISCO.

The manhole cover hook is fabricated at the plant and made spark proof by covering the hook with brazing rod.

The next three photos show the pretreatment sampling van. Some equipment was made or modified by the plant maintenance staff. Other materials were purchased through American Van.

Equipment is tied down with straps to perforated metal. Long poles are secured to the ceiling with broom clips and PVC pipe.

Sampler Modification for Process Control Samples

By: Waukesha Staff

Our in-plant process samples are taken locally with manhole samplers placed in hutches. Because the samples are for process control only, the samplers are not iced. A light bulb provides heat in the winter to prevent freezing.

It is cumbersome to change the sample bottles in the manhole samplers, so we modified the sampler unit. The sampler head was taken off and mounted on a shelf that can be pulled out like a drawer for easy access. The sample container is mounted below on a suspended shelf.

Changing samplers is now much easier. Pulling out the shelf exposed the sampler head for adjustments or resetting. The sampler container has easier access for nightly changing.

Throttling Valve Reduces Sample Line Splashing

By: Sheboygan Treatment Staff

We've had a problem with opening sample valves and then getting splashed. The problem was especially bad with primary sludge sampling...where the sludge line does have some line-pressure. We found that partially closing a valve upstream of the sample collection valve prevents the sudden...fast flow of sludge that causes the splash. Adding a water flush line at the sample valve allows the whole sample line to be back-flushed...which also reduces problems too.

Using Peristaltic Pumps for "Messy" Samples

By: Sheboygan Treatment Staff

The low-cost "unofficial sampler":
We bought the sampling head of a well known commercially available sampler....then coupled it with a relatively low-cost "dorm refrigerator." The refrigerator may not maintain perfect 4C temps...but it is a low-cost option for "process samples."

RAS/WAS sampling from the RAS pump bleed valve or discharge lines. We added a sample tube adapter to the bleed valve for the RAS pump. Discharge pressures are low, but we do have a hose-clamp to assure a reliable connection. If that's not workable, it would probably work to connect a very short tube to the RAS line itself. We keep life simple with a time-proportional control scheme. ML Sampling was accomplished by running an insulated sample line from our blower building into the aeration basin. We do have a heat-trace on most of the line....but kept it away from the liquid level. Efforts were made to keep the line as short as possible. Again, samples were taken with a time-proportional control scheme.

The units have proven effective to get a consistent sample. Samples are "always taken" even when times are hectic e.g. during a storm and we've reduced the operating staff from handling filthy cups, & rubber gloves.