Global Processing

Moisture analyzer streamlines wastewater processing for Lynden plant

September 3, 2003
Water quality is an important issue for every person on the planet. Polluted water and inadequate sanitation kill two children every minute worldwide. In the United States we sometimes take for granted how fortunate we are to have a network of wastewater facilities providing us with a safe environment and recycling of the precious commodity of fresh water. Wastewater treatment plants scrutinize incoming wastewater and check for compliance under federal and state compliance as well as its compatibility with plant operations. Once in the plant, the sewage undergoes a series of physical, chemical and biological processes to treat the wastewater to remove harmful dissolved and suspended solids. Once removed some of the biosolids (commonly known as sludge) is further treated and recycled as fertilizer. The treated water is then disinfected and released.

    Wastewater treatment plants across the country must comply with stringent federal discharge permit levels. To meet these levels a wastewater operator must evaluate water quality and make the necessary adjustments in the plant. Solids testing is one such requirement. In order to maintain a healthy plant an operator must monitor the Total Suspended Solids levels of the Mixed Liquor, Return Activated Sludge (RAS) and Waste Activated Sludge (WAS) throughout the day. Standard laboratory testing for Total Suspended Solids requires that a sample be weighed and then dried in a lab oven for one hour. The sample is then re-weighed and compared to the initial weight to determine the % of solids.

    It is also essential to monitor the solids handling process; solids levels are monitored in a different procedure called "Total Solids" testing. This method takes 24 hours drying time in the oven. While these lengthy procedures are required for incoming and outgoing waste because of plant certifications, it costs valuable time and it is not required during daily process control.

    Tami Adams is Chief Operator for the City of Lynden Wastewater Treatment Plant, which is located in northwest Washington and treats an average of one million gallons per day. Tami was looking for a more efficient way to run the treatment plant. She knew from previous experience that reducing the time for analysis would save time and money.

    There were a number of opportunities at various process stages to shorten time spent on analysis.The thickening and dewatering of biosolids was one such area. If cake solids (dried sludge) contain too much water, disposal is more expensive.If thickened sludge during drum thickener processing reaches a 5% level, expensive polymer dosing can be reduced, saving thousands annually at this facility.

    Knowing that a moisture analyzer would help, Adams went to her trusted laboratory supplier and asked what they could recommend. She needed equipment that was fast, easy-to-use, extremely accurate but fit easily into a budget. While the supplier carried several brands, the reply was conclusively the A&D MF-50 Analyzer.

    The MF-50 offers the highest repeatability among all moisture analyzers in its class: 0.01% standard deviation.Three different operation modes give the unit powerful flexibility: standard, quick, and temperature step. The MF model displays moisture content to 0.1%, and memory function allows users to program up to 20 different sample testing parameters including temperature, time, or % delta of moisture change.The automatic mode stops the testing based on a selected drying rate. The new Optimum Temperature Setting (OTS) function takes the initial guesswork out of deciding what settings to use for different samples by making its recommendations after one test run.

    Laboratory testing that once took an hour in a lab oven can now be accomplished in two to three minutes for process control. Total Solids testing that once took 24 hours can now be done in approximately ten minutes.

    "The A&D MF-50 Moisture Analyzer has not only been a timesaver but it has dramatically increased our plant effectiveness," stated Ms. Adams. "We receive process data in minutes not hours, allowing us to rapidly fine tune our operations and save money."

    Each week the Lynden Treatment Plant compares the A&D analyzer results with the time consuming conventional standard methods, and the results always correlate very positively.

    "Along with all the different operators at the plant, I like that it so simple to use," affirmed Tami. "The automatic stop function means that we just load a sample, push a button and take a reading in a few minutes once it''s complete. But most importantly, it''s accurate. The citizens of Lynden depend on us, so it has to be."

    The City of Lynden, Washington has a population of around 10,000 and states as part of its vision: "Being good stewards of the environment and the economy are essential to preserving the city''s sense of community, security and its unique identity". A&D Weighing is pleased that Lynden has chosen A&D Weighing''s superior technology to w ork towards that vision.