| Author | Bhavana Likhananont |
| Call Number | AIT Thesis no.SR-97-26 |
| Subject(s) | Sewage--Purification--Biological treatment
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. SR-97-26 |
| Abstract | Composting can be one of the appropriate means to manage sewage sludge
created in Bangkok Metropolitan area. Considering the amount of some heavy metals already
existed in the sludge, problems of composting sewage sludge be generated especially when
composting inocula which consist of various types of microorganisms are applied to the
composting process.
To achieve some data concerning making compost from Bangkok sewage
sludge by adding specific microbial inoculum named QCTC, three experiments were conducted.
They were an experiment on sewage sludge characterization, an experiment on effect of some
significant metals found in the sludge on the growth of composting microorganisms and an
experiment on effect of microbial inocula on composting sewage sludge mixed with rice hulls.
The results of the experiments showed that Sipraya sewage sludge comprised
copper, zinc, chromium and nickel of the concentration of 801, 1,220, 310 and 282 mg/kg of
the sludge, respectively. Moisture content of the sludge was relatively high, about 80 % which
is not suitable for composting. Therefore, the sludge needed to be dried. pH of the sludge
was about 6.5 when measured with water at the ratio of 1:5 (weight by volume).
Microbiological study of the sludge showed that this activated sludge still contained a high
number of microorganisms up to about 2 x 109 cells/gram of sludge of which were seven
bacteria, one actinomycetes and eight fungi. When these microorganisms were tested for their
cellulolytic activity, it was found that all fungi and an actinomycetes performed the activity
whereas bacteria did not.
Experiments done on effect of some metals which were found existent in the
sludge on the growth of composting microorganisms showed that most of the metals tested
especially copper and zinc had a negative influence on the microorganisms tested. On the
contrary, the extract of the sewage sludge showed no effect on the growth of these composting . . mtcroorgarusms.
When sewage sludge was composted with or without rice hulls, it was observed
little decomposition. The highest temperature of every compost pile was about 41° C and was
not more than this degree which was considered lower than it should be and the temperature
had been raised up only for short period about 3-5 days after starting the operation. Compost
piles with or without microbial composting inocula did not show any differences on percentage
volatile solids and carbon to nitrogen ratio of the compost samples which were used as
parameters of composting process for this study. Quantity of macro nutrients (N, P and K) in
the compost produced from sludge were also analyzed and it was found comparatively high
when compared to the compost produced from other sources. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. SR-97-26 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Space Technology Application and Research (SR) |
| Chairperson(s) | Preeda Parkpian |
| Examination Committee(s) | Apisit Eiumnoh;Eckhardt, Heinz |
| Scholarship Donor(s) | The United Kingdom |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 1997 |