Recent content by sewerfix

ch81pc Thanks for your observations. We plan to have an elevated silo for direct loading into trucks in order to mitigate the amount of conveying. Inclined belt conveyors to get the product up to the silos.

We're looking at biosolids storage silos for 23% aerobically digested WAS. If anyone has practical experience with sliding frame (push floor) silos can they comment on their effectiveness, does the product deteriorate through the mechanical workings of the outloading system etc. Thanks Andrew

Does anyone have practicall, working knowledge of struvite control strategies. I know of ferric being used to lower ph, reducing precipitation potential to bind with phosphate and remove it from solution before struvite can form. I've heard that aluminium salts are more effective then iron. I'm...

I'm looking for a flow switch to be mounted downstream of existing gas compressors to confirm operation / detect failure. I'm reluctant to use a thermal flow switch because of possibility of grease build up etc. The pipe is 2" steel Can anyone suggest a reliable instrument?

What are the pros and cons in using knife gate valves with polyurethane seats for municipal sludge applications. Obviously the suppliers talk about abrasion resistance, however I'm just curious if there are any negative aspects such as not being able to achieve a positive seal where foriegn...

Berko, The biggest headache with the Vaughan system is the floor piping (and capital cost). Any internal tank piping is going to be an obstruction to the mixing application, especially if it is compounded by heavy sludges. To optimise the mixing efficiency we installed piping just above the...

Hi Berko, From my research I have come to this general conclusion - submersible mixers are only reliable with sludges of up to 5% solids. Submersible mixer suppliers are very reluctant to provide a process / mixing guarantee beyond this characterisitc. Top entry agitator suppliers I find size...

Does anyone have experience with pigging of municipal sludge pipelines? in particular the use of welded bars in tee braches to stop pigs catching etc. I'm concerned about the buildup of sludge / rags on such bars being a source of high maintenance. Are there other tricks to ensure a foam pig...

I'm looking for a tank mixing tank system suitable for a solids content of between 4- 7% w/w solids content. We have two sludge stream coming into a blend tank and the mixing system should blend and keep the solids in suspension before being processed through our new sludge thickening facility...

Can anyone recommend a reflux (non-return) valve suitable for municipal sludge applications approx 5% solids? We have had very limited success with full bore swing check valves having resilient seats. I didn't know if the slurry pumping industry used something unique for solids laden fluid...

We had problems of hypo gassing in the pipelines at a small installation causing the diapham pump to not pump liquid until the gas lock was pasted. The issue is well known to pump suppliers and hence we had to replace the pump head with one that included an automatic de-gassing head. A bleed...

I'm looking for a non-contact density meter to monitor solids content of a 3 - 8% municipal sludge application. We have nuclear density meters onsite and the problem is that they require constant cleaning, making the instrument unreliable. The thickened primary sludge periodically creates a...

We have a centrifugal pump that is powered by a 675kW DC motor (two speed) which we want to replace with AC motor and AC-VSD control. Is it as simple as requiring a 675kW AC motor ? Are there other factors , derating factors to consider in relation to the starting characteristics of AC versus DC...

From my background in waste water treatment plants, we always used shaftless spiral conveyors for inlet works screenings, grit transfer and dewatered sludges. In specifications I only ever see shaftless conveyors. I'm doing a subject at Uni - Materials Handling and the lecturer is from the...

General Question What would the selection criteria for using shaft versus shaftless screw conveyors? Are there any major advantages of one over the other?