1983-10-26 Workshop Meeting - Laserfiche WebLink

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.,...- e e ~=- -11Jo .- - -'-- ....-.- -"---"--, . . TurnerC911ie0Braden Inc. July 29, 1983 Mr. Jerry L. Hodge City of La Porte .,. Page Three The probable rate of flow in this pipeline is not high enough to prevent settling of solids in this pipe, even during wasting periods. Most of the time the rate of flow will be zero, which will allow further deposition of solids and will increase the potential for the pipe to clog. .The reia:a~elY ;'ic;~~1::;li;~~~.-~~~~~p: ,~;;,4;g~~~~r'::~a 'thickener',""and the. smalI.d1fferenceffi..water surface elevations'l between~'tnese'l~st;ruct.iires'~''<''woula'~'nott be a' ;'~ecOnlli\~ded -iarraii9emen€~?UnlesB'>waste;' 'sludge"pmnps, 'were' ;''1:>rovided.',f Our cOnclusion'is that the' arrangement of the structures and the piping system is very likely to con- triQute to the pipe clogging and may be totally responsible for the problem. This problem could have been minimized or eliminated by locating the structures closer together, increasing the difference in water surface elevations, 'providing a waste.. sludge. pump... station ;or by a. combination 'of these methods.,.~~t.~~..this;.:'tiriie?'~the '~only positive solution would be to' provide'-.~~waste _ sludge ~pumps ~t '" -'." . .; ..:,,:~. ~ ,t,.-,' ;;.:.._;,.:..~..,.tk::;.~..~~.d;.i.:.,t:"i'f.-...tit'~::,'.:~t>:-;.. . '~'.." .;J Ou~'recommendations for operational procedures to minimize th~~ problem are as follows. a. Thoroughly clean the piping system. b. Maintain the water surface elevation in the thickener below the overflow weir, at or slightly above the point of discharge in the center feed pipe. This will require the operators to pump out or siphon the supernatant, or else will require modifications to the overflow trough and piping. c. Maintain the water surface elevation in the digester at the maximum practical elevation (approximately elevation 23.19). d. Minimize the wasting period so' as to maximize the ~waste sludge flow rate and velocity. Do not attempt to waste continuously or for extended periods of time. Flush the sludge piping with process water after each wasting period. -- C .:..- - -' "