I N D U S T R I A L W A S T E W A T E R P R O B L E M S
PROBLEMS IN THE OPERATION
OF PLANTS TREATING MIXED
INDUSTRIAL WASTES
PETER FARKAS
Senior Research Biologist, Research Institute for Water Resources Development,
VIII Rakoczi ut 41, Budapest, Hungary
Operation of plants treating wastes from many sources, industrial as well as municipal
ones, introduces technical as well as legal problems. As the influent waste flow and
concentration are subject to sudden changes, spills and slugs, then overloading or
poisoning may occur, with subsequent effluent quality deterioration. What we need
would be a theoretical basis for the elaboration of directions for operators and
dischargers, that would ensure trouble-free plant operation.
In the present study, we will discuss the following questions:
— The conditions of stable biological plant operation
— A model describing the effect of mixed wastes on biological oxidation
— The prediction of effluent quality changes on the connection of new dischargers to
existing plants.
The conditions of trouble-free plant operation:
The following conditions have to be assured:
— Effluent quality (BOD 5 or COD) should not exceed the limiting value prescribed,
— No great fluctuations in waste load should be tolerated, because they cause sludge
bulking, septic conditions, or sludge wash-out,
— Poisoning should also be avoided, because it may make a new start-up necessary.
Characterization of biological treatability of industrial wastes
It is evident that only wastes having no adverse effect on the biological process can be
discharged to biological treatment plants. Biological treatability of wastes, however, can
be characterized by the substrate concentration function of removal rate.
Biological reaction rates are a sum of substrate and endogenous metabolism processes:
r = r s + r e
(1)
where r denotes the overall reaction rate, characterized by some non-specific reaction
(e.g. respiration), r s is the substrate oxidation rate, described as below:
»-£--'* (-£-)
e>
and r e is the endogenous respiration. In Equs. (1-2), S denotes substrate concentration
and k^ its oxygen equivalent. In the present rationale, all the pollutants contained in
discharge are regarded as substrate, irrespective of whether they are poisonous or
biologically removable.
In the development of a function for the description of biological properties, we start
from the dimensionless form of Equ. 1 (1), obtained after dividing it by the basic
respiration, r 0 . This latter can be measured after aeration of the sludge for some time in
order to have all dissolved substrate removed. So we can introduce the R dimensionless
549
PROBLEMS IN THE OPERATION
OF PLANTS TREATING MIXED
INDUSTRIAL WASTES
PETER FARKAS
Senior Research Biologist, Research Institute for Water Resources Development,
VIII Rakoczi ut 41, Budapest, Hungary
Operation of plants treating wastes from many sources, industrial as well as municipal
ones, introduces technical as well as legal problems. As the influent waste flow and
concentration are subject to sudden changes, spills and slugs, then overloading or
poisoning may occur, with subsequent effluent quality deterioration. What we need
would be a theoretical basis for the elaboration of directions for operators and
dischargers, that would ensure trouble-free plant operation.
In the present study, we will discuss the following questions:
— The conditions of stable biological plant operation
— A model describing the effect of mixed wastes on biological oxidation
— The prediction of effluent quality changes on the connection of new dischargers to
existing plants.
The conditions of trouble-free plant operation:
The following conditions have to be assured:
— Effluent quality (BOD 5 or COD) should not exceed the limiting value prescribed,
— No great fluctuations in waste load should be tolerated, because they cause sludge
bulking, septic conditions, or sludge wash-out,
— Poisoning should also be avoided, because it may make a new start-up necessary.
Characterization of biological treatability of industrial wastes
It is evident that only wastes having no adverse effect on the biological process can be
discharged to biological treatment plants. Biological treatability of wastes, however, can
be characterized by the substrate concentration function of removal rate.
Biological reaction rates are a sum of substrate and endogenous metabolism processes:
r = r s + r e
(1)
where r denotes the overall reaction rate, characterized by some non-specific reaction
(e.g. respiration), r s is the substrate oxidation rate, described as below:
»-£--'* (-£-)
e>
and r e is the endogenous respiration. In Equs. (1-2), S denotes substrate concentration
and k^ its oxygen equivalent. In the present rationale, all the pollutants contained in
discharge are regarded as substrate, irrespective of whether they are poisonous or
biologically removable.
In the development of a function for the description of biological properties, we start
from the dimensionless form of Equ. 1 (1), obtained after dividing it by the basic
respiration, r 0 . This latter can be measured after aeration of the sludge for some time in
order to have all dissolved substrate removed. So we can introduce the R dimensionless
549