57    DEVELOPMENT OF A LAND LIMITED BIOLOGICAL
PRE-TREATMENT PROCESS FOR HOSPITAL AND
FOOD PROCESSING WASTEWATER
Yi-Chang Lin, Associate Professor
Jin-Huei Hsu, Research Associate and Doctoral Student
School of Public Health, National Taiwan University
Taipei, Taiwan, Republic of China
T. Ma, Graduate Research Assistant
P. Y. Yang, Professor
Department of Biosystems Engineering
University of Hawaii at Manoa
Honolulu, Hawaii 96822
INTRODUCTION
The rapid growth of population and agro-industry in Taiwan and the state of Hawaii has been very
obvious in the past decade. Consequently, both domestic and agro-industrial wastewater have been
considered as the two major sources of water pollution problems. Because of the social and economic
requirements, both the hospitals and food processing plants need to be located in the populated city or
near the urban areas. Thus, the related wastewater treatment alternatives have some limitations; such
as, limited land, less capital, shortage of labor, concerns regarding odor, and overload of existing
domestic sewer systems. The pre-treatment alternatives for reducing the organic load of the existing
domestic sewer system require an effective treatment process which can provide the following merits:
• less land requirement
• less starting up period
• simple to operate and maintain
• less sludge production
• no odor or less odor problems
• easy to be prefabricated
Although some physical/chemical pre-treatment alternatives may provide the above merits, the cost
is one of the main concerns of using physical/chemical pre-treatment. Therefore, the entrapped-
mixed-microbial cell (EMMC) process was selected as a biological treatment alternative in order to
meet the above merits. The EMMC process is a comparatively new technology in the field of water
and wastewater treatment. Entrapment is accomplished by using porous or fibrous material to confine the migration of organisms. It is expected that the EMMC process will provide higher SRT's
(Solid Retention Time), eliminate external sludge recycling and prevent bulking/rising sludge that
occurs in the conventional activated sludge process. Removal of organic and inorganic compounds
using the entrapping technology for pure culture was investigated previously.1"10 Also, the entrapping
technology of using mixed culture for entrapment of wastewater treatment was investigated.""17
Among these studies, various types of polymers were used for the cell entrapping carrier. In general,
the biological removal efficiency was high. Advantages and disadvantages of using these microbial
cell technologies for wastewater treatment were presented and discussed in the above previous studies.
Based on the experiments using entrapped mixed culture of microbial cells for biological wastewater
treatment at the University of Hawaii,12"17 it was found that cellulose triacetate could provide the
necessary mechanical strength and durability under both the aerobic and anaerobic conditions in
treating the synthetic wastewater. Therefore, it is necessary that the technology be further investigated
for actual wastewater as substrate in order to evaluate its feasibility for application in land limited
conditions. This paper reports the results of applying the cell entrapment technology by using both
synthetic and actual organic wastewater as substrate and evaluation of its potential for serving as a
pretreatment method for achieving the domestic sewer discharge standard.
49th Purdue Industrial Waste Conference Proceedings, 1994 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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