Sewage
sludge disintegration
Definition
"Sewage sludge disintegration" is
the stressing of sewage sludge through external forces. Physical, chemical and
biological forces are applicable for the disintegration. The effect of these
forces is the decomposition of the flocculent structures within the sludge
and/or a breaking-down of the micro organisms embodied in the sludge.
This procedure leads to a distinct decrease in particle size of the sludge and
also to a release of organic sludge components into the liquid phase.
Objective
The purpose of sewage sludge disintegration
is the release of cell components in order to stabilize the sludge more rapidly
and more extensively as well as a reduction of foam problems.
The actual operational areas of sewage sludge disintegration are the
improvement of the anaerobic stabilization, provision of internal hydrogen
sources for the denitrification process and a better sedimentation of the
sludge, especially of bulking sludge.
Development
In Berlin, Mannheim and Braunschweig the
first systematical investigations of the disintegration of sewage sludge have
been started almost at the same time, but independently, in 1990/91. The promising
results lead to the project: "Improved Degradation of Sewage Sludge by
Cell disintegration", at the Technical University of Braunschweig,
supported through the German Research Council. Through the common work of four
University institutes a significant contribution to the basic research of this
new process of sludge treatment has been made.
Workshops and conferences
Because of the desire to bring together the
growing number of work groups for a scientific exchange we hosted a workshop in
March, 1996 with the topic: "Mechanical sewage sludge disintegration and
anaerobic degradation behavior". The workshop provided an opportunity for
a scientific exchange within a small group for scientists and other practical
users who are working actively in this field. The lively and fruitful
discussion has lead to a repeat of the workshop in March, 1998.
The situation in 1998 changed in comparison
to 1996. The representatives of communities and associations, the managers, the
planners and others were asking us to offer an informative conference about
this topic. This shows how large the need is for information regarding
possibilities and limits of this new technology. We satisfied the need for
knowledge during the first conference concerning this topic at the TU Braunschweig
in March 1998 , titled: "Sewage sludge disintegration - research and
application". The proceedings
of this conference are available in German language only.
ATV-workgroup
In June 1998 the new ATV
workgroup 3.1.6 "Disintegration of Sewage Sludge" was found. The
members are from Universities, associations and consultants. The goal of the
group is to inform all ATV members about backgrounds, chances and limits of
sewage sludge disintegration.
At first the workgroup focused on the treatments of mechanical disintegration.
Thermal, chemical, physical and biological treatments will be part of the work
and they will be more deeply discussed in the future. Within the workgroup
there is going to be an evaluation of the different mechanical disintegrations.
Aspects, like technical realization, implementation into the sewer plant
processes, specific energy consumption and the economic efficiency are
investigated.
In this course the knowledge, acquired in pilot plant and full scale, will be
accumulated, to offer information for potential users. The homepage of the
ATV-workgroup gives detailed information and a large section of references in
the field of sewage sludge disintegration.
Research
Since 1991 have the institutes of
"Mechanical Process Engineering" and "Sanitary Engineering"
of the TU Braunschweig been researching the field of sewage sludge disintegration.
A number of research works have been
produced. In the following is given a list of the topics of these works.
·
Comparison of different methods of Sewage Sludge
Disintegration
·
Improvement of the anaerobic degradation behavior