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When selecting an AFD for a small motor (30 hp), would the AFDs selection depend on the make of motor or as long as the AFD is manufactured in North America (NA)it would be generally compatible with any NA manufactured pump motor? Thanks in advance

Under what conditions should flexible joints(Eg. Bellow type) be provided on suction and discharge piping? I have a low lift 30 hp sewage pump application and I am curious to find out whether these are really required as I hardly see these on most of the pump applications I come across. Thanks...

We have a old Smith and Loveless below grade "can" type duplex raw sewage pump station (20 hp each). The existing pumps are so old and therefore needs replacement. My first thought was to use dry pit close coupled submersible (By Sulzer, Xylem) but can we also consider dry pit sewage pumps...

Good day, Is there a recommended max speed limit for positive displacement pumps used in primary sludge application. If so what is the value? We have to frequently replace the seals of our constant speed primary sludge pumps running at 350 rpm. We have experimented with different seal material...

Good day all, I am having trouble in trying to calculate the Aluminum (Al) wt. in the liquid alum that is dose at one of our treatment plants. The alum (Al2(SO4)3.18H2O ((48%) - Molecular wt. 666.132) daily dosing wt is 101.63 kg/d. If so would the Al (MW =27) daily dosing wt. be =...

I am trying figure out the NPV of a AFD used with a 100 hp motor. Generally what is the lifespan of a VFD? Thanks in advance.

I am trying figure out the NPV of a AFD used with a 100 hp motor. Generally what is the lifespan of a VFD? Thanks in advance.

We have a lightly loaded (BOD5 -100 mg/L) municipal extended sludge plant (1500 m3/d) that sees almost zero flows during the off peak times. (3- 5 hrs/day ). As a practice we run the RAS pumps continuously throughout the day. In order to save energy is it okay to shut off the pumps when there...

What impact would it have if the tested UC of sand is 12% less than requested in the specifications. Effective size matched the specifications. The sand is used for a wastewater polishing bed. Thanks

I find that the preferred method for process control in conventional activated sludge, extended aeration, oxidation ditch systems in the MLSS control as the analysis is simple and straightforward. I am interested in hearing about the forums members experience on this topic. Are there plants that...

This could be a silly question. Could there be a substitute for a Pressure Reducing valve (PRV). We have to installed a PRV between two pressure zones in our distribution system. To maintain a redundancy in case of the PRV malfunctioning we want to install two PRV units side by side. I am...

What could be the impact of receiving industrial wastewater from a food processing factory that has high COD ~ 5000 mg/l and BOD5 = 2500 mg/l to a municipal wastewater treatment plant that treats domestic wastewater with BOD=200 mg/l?. The factory discharge is about 5% of the total plant flow...

I want to have two (2) 1/2" tap connections for directly (without any saddles) connecting pressure gauges (via isolation valve) on the Ductile Iron C110/A2.10 pump suction and discharge pipes (16" and 10' respectively). The plan is to use nipple and ball type shut off valves at the tap to...

Could a dry pit submersible pump operate under negative suction provided that NPSH and min. submergence of the suction bell conditions are met at the design flows? I have a situation where I am trying to replace an existing dry pit with a new dry pit submersible. The minimum water level in the...

What is the best way to allow a 1.5 inch movement (Axial only) due the temperature difference for a 36 inch 316L stainless steel pipe (convey hot air) through a vertical wall of building. The pipe is anchored inside the building but I am trying to permit a 1.5 inch free axial movement for the...

Would a type 316 valve welded to a type 304 stainless steel pipe lead to the corrosion of the 304 pipe? Application is clean water. If so what is the best way to protect the pipe without changing the pipe material. Thanks is advance.

Does anyone in this forum have experience using butterfly valves (BFV) for flow throttling services? How successful has that been? I have a need to control the flow through a activated sludge returned sludge line using a valve. I typically use plug valves (PV) for this application but at some...

There is situation where pump discharge (located close to the upstream end) drops vertically into a long horizontal channel. The channel is relatively flat. The channel discharge is controlled by a downstream weir. What is the best way to determine the water surface elevation at a location where...

Has anyone used stainless steel (Type 316) buried pipes for process air services? I have to design a 1000 mm SS pipe buried 1.5 m below grade for air services. The total length of the pipe is about 150 m. The temperature can vary between 0 ~ 100 C. If so what is the best way to provide...

Could someone let me know the equations that can be used to calculate, the temperature rise in a high-speed turbo blower if; 1. Inlet pressure and temperature 2. Outlet pressure are known. the power requirement for a high-speed turbo blower if; 1. air mass flow rate 2. inlet and...