EFFECTS OF EXPOSING SLIMES ON ROTATING DISCS
TO ATMOSPHERES ENRICHED WITH OXYGEN
*W. Torpey, H Heukelekian, A J Kaplovsky and L. Epstein
*Project Director, Department of Environmental Sciences, Rutger's University,
New Brunswick, N.J.08903, U.S.A.
INTRODUCTION
The authors published results of the operation of a rather sophisticated pilot plant
utilizing rotating disks to treat effluent from the primary tanks of the Jamaica Water
Pollution Control Plant in New York City, for the period July to November, 1969
(Torpey et al, 1971). It was operated with partially submerged disks, alternately
immersed in the waste-water and exposed to normal atmosphere in all stages of
treatment.
In this paper the results are given of subsequent pilot plant studies wherein one or
more stages of treatment were enclosed with a hood so that the slimes were exposed to
atmospheres enriched with oxygen, Accordingly, for comparison purposes, the results
obtained during the base period when all stages were operating under normal atmosphere
are included.
EQUIPMENT
The pilot plant comprised three main component parts: (a) Ten stages of rotating disks
for the removal of org^nics and for oxidation of ammonia to nitrate, (b) six stages of
illuminated rotating disks for the removal of nitrogen and phosphorus from the effluent
of the preceding system by synthesis into attached algal cells, and (c) six packed beds of
granular activated carbon columns for the adsorption of residual organics from the
preceding algal system. Sedimentation of 1.5 hours was interposed between the effluent
from the ten stage unit and the algal unit. A mixed media filter preceded adsorption in
carbon columns for removing the particulates, which were mainly algal cells generated on
the illuminated disks.
The flow through the ten stages was 28.39 1/min. ±10%, whereas the algal unit rate
was 11.35 1/min. Flow to the pressure downflow carbon columns was at a surface loading
of203.6 1/min./m
2 .
Each of the ten stages consisted of a horizontal shaft with 48, .91m diameter, .16 cm
thick aluminum disks which were spaced on 1.27 cm centers. Effective area was sacrificed
to the extent of 11% by the use of 0.3m diameter spacers between the disks. These
aluminum spacers were used to provide rigidity and proper alignment to the thin
aluminum disks. Each shaft was driven by a hydraulic motor at rotational velocities of 6
to 10 R.P.M. The disk assembly was placed in a half-formed cylindrical tank so that 45%
of the disks were submerged. Flow was perpendicular to the shaft. There was no
intermixing between stages. Disk rotation was opposite to the direction of flow through
the stages. The theoretical detention time was six minutes in each stage, measured when
the disks were devoid of slime. The actual time was somewhat less, depending on the
degree of displacement of fluid volume by the slimes. The primary tank feed originated
from a 600,000 population wastewater plant.
405
TO ATMOSPHERES ENRICHED WITH OXYGEN
*W. Torpey, H Heukelekian, A J Kaplovsky and L. Epstein
*Project Director, Department of Environmental Sciences, Rutger's University,
New Brunswick, N.J.08903, U.S.A.
INTRODUCTION
The authors published results of the operation of a rather sophisticated pilot plant
utilizing rotating disks to treat effluent from the primary tanks of the Jamaica Water
Pollution Control Plant in New York City, for the period July to November, 1969
(Torpey et al, 1971). It was operated with partially submerged disks, alternately
immersed in the waste-water and exposed to normal atmosphere in all stages of
treatment.
In this paper the results are given of subsequent pilot plant studies wherein one or
more stages of treatment were enclosed with a hood so that the slimes were exposed to
atmospheres enriched with oxygen, Accordingly, for comparison purposes, the results
obtained during the base period when all stages were operating under normal atmosphere
are included.
EQUIPMENT
The pilot plant comprised three main component parts: (a) Ten stages of rotating disks
for the removal of org^nics and for oxidation of ammonia to nitrate, (b) six stages of
illuminated rotating disks for the removal of nitrogen and phosphorus from the effluent
of the preceding system by synthesis into attached algal cells, and (c) six packed beds of
granular activated carbon columns for the adsorption of residual organics from the
preceding algal system. Sedimentation of 1.5 hours was interposed between the effluent
from the ten stage unit and the algal unit. A mixed media filter preceded adsorption in
carbon columns for removing the particulates, which were mainly algal cells generated on
the illuminated disks.
The flow through the ten stages was 28.39 1/min. ±10%, whereas the algal unit rate
was 11.35 1/min. Flow to the pressure downflow carbon columns was at a surface loading
of203.6 1/min./m
2 .
Each of the ten stages consisted of a horizontal shaft with 48, .91m diameter, .16 cm
thick aluminum disks which were spaced on 1.27 cm centers. Effective area was sacrificed
to the extent of 11% by the use of 0.3m diameter spacers between the disks. These
aluminum spacers were used to provide rigidity and proper alignment to the thin
aluminum disks. Each shaft was driven by a hydraulic motor at rotational velocities of 6
to 10 R.P.M. The disk assembly was placed in a half-formed cylindrical tank so that 45%
of the disks were submerged. Flow was perpendicular to the shaft. There was no
intermixing between stages. Disk rotation was opposite to the direction of flow through
the stages. The theoretical detention time was six minutes in each stage, measured when
the disks were devoid of slime. The actual time was somewhat less, depending on the
degree of displacement of fluid volume by the slimes. The primary tank feed originated
from a 600,000 population wastewater plant.
405