9/12/2023 0 Comments Drawdown testIt turns out that neither was the culprit. Is this reduced flow and increased head due to a blockage in the discharge pipe, or was the original design point incorrect? Based on the performance curve, the pump is operating at 55 feet instead of the design point of 48 feet. Suppose we perform several draw down tests and compute an average flow of 350 gpm. When possible, we like to use one foot because little change in flow occurs for most pumps over such a small elevation change. Dividing the volume by the time in minutes provides us the flow rate in gallons per minute. In a standard draw down test, the wet well volume per foot is calculated and the time required to lower the water level one foot is recorded. In this example, any friction in the discharge piping will be ignored. The red, horizontal line is the system head at the pump-start level in the wet well. Pump curve for a duplex lift stationįigure 1 shows the pump curve for a duplex lift station that was designed to pump 400 gallons per minute (gpm) into a gravity main against a static head of 48 feet. Pressure must also be measured to assess the true performance of the station.įigure 1. However, flow rate alone may not provide all the needed information. Often, a draw down test is used to measure pump flow rate, and then flow rate is used to determine where the pump is running on the H/Q curve. This testing method can be reliable as long as the data collected is accurate and the test is repeated several times to ensure reliability. In the Northwest, the vast majority of these stations use draw down as the standard pump test technique. Although it accommodates several different pump designs, wastewater pumps were a major focus.įlow meters are becoming more popular in many wastewater applications, but justifying their cost in smaller lift stations and those that are not connected to a SCADA network is often difficult. In February 2011, I wrote an article on my Field Test Calculator. In 2010, this column discussed unbalanced radial thrust and how the wide vane impellers used in wastewater pumps are extremely vulnerable to the damage it can cause. Last month, I revisited suction recirculation and its potential effects on wastewater pumps due to the rather large eye diameter to impeller diameter ratio. The results of water sample analyses show water quality is excellent and acceptable for drinking purposes, according to the Jordanian water standard 2008, and EU drinking water standard 1998.Based on several of my previous Pumps & Systems articles, you probably know that I have major concerns about the off best efficiency point (BEP) operation of wastewater pumps. The obtained results were found to be corresponded to the unconfined nature of in the encountered aquifers in A1, A2, A3, A4, A5, A6, A7, A8, and B1, B2, B3, B4 wells, and this is clearly indicated in the storage coefficient (specific yield) of this aquifer in these wells. The large transmissivity of the Disi aquifer is indicated between 541 to 656 m 2 /day of yielding wells and the storage coefficient in the range 0.0199 to 0.0260, the specific capacity in range 5.9 to 7.11 l /s /m. The most important feature of the Rum aquifer is its homogeneity in the grain size ranges between 0.25mm to 0.51mm sand, the uniformity coefficient ranges between 1.36 to 2.19 at different formations depth between 330m to 520m, medium to fine and medium to coarse uniformly graded sand of different formations. The Rum aquifer system represents an unconfined aquifer system in the area in which no deposition of Khreim group where Khreim group overlies the Rum sandstone deposits. The groundwater flows from the Saudi Arabia in the South towards North East Jordan in central Jordan. ![]() The Disi aquifer, which is the main source of water for Mudawara Region, is one of the most permeable and productive Sandstone aquifers in the Jordan. The rock formations constituting the Rum group compose the Rum aquifer system, which dominates the fresh water aquifer system in southern Jordan which the aquifer system in southern Jordan which the rock formations constituting the Khreim group represent the confining layer where Sahl Suwaan formation occur. These formations are Saleb, Burj, Umm Ishrin, Disi, and Umm Sahm formations. The aquifer is composed of rock units overlaying the basement complex of the Precambrian ERA are subdivided into two groups: the upper group is called Khreim group, and the lower group is the Rum group.
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