啤酒厂废水生物处理全套毕业设计-外文原文pdf文档

本资料包含pdf文件1个，下载需要1积分

破厂废水生物处理全套毕业设计-外文原文
ntroduction
Fixed growth biological process and activated sludge process are popular methods in biological
treatment of wastewater. In comparison with activated sludge method ， fixed growth process holds more
biomass per unit volume in the reactor ， thus improves the loading capacity of the reactor. Meanwhile ， it
eliminates the sludge 2 bulking problem and reduces the yield of residual sludge at the same time. Despite
the above advantages of fixed growth process ， the shed of microbe is often unavoidable in practice. The
results in the need of a secondary sedimentation ， which not only complicated the treatment processes ， but
also reduced the biomass in the reactor and produced unexpected residual sludge as well .
Fig. 1 Separated membrane biological reactor
Ultrafiltration membrane ， which can
entrap almost all creatures in the biological
reactor ， was introduced into the biological
membrane reactor to solve this problem so that
the capacity of the reactor could be enhanced
and the quality of the outlet be improved as
well. Traditional secondary settlings are
replaced with membrane components in
Fig. 2 United membrane biological reactor
biological membrane reactors ， which is a
combination of biological techniques and
membranous techniques. Ultrafiltration
membrane was used in the solid 2 liquid
separation of activated sludge in 1969 ( Smith ，
1969 ) . In 1971 ， when the technique was
applied in sewage plant for strict treatment of
wastewater ， it was discovered being able to reduce the residual sludge yield by keeping a low return flow
proportion. In 1992 ， membrane biological reactors are used in the research of denitrogenation ( Yuichi
Suwa ， 1992) . One year later ， it was found that due to the entrapping function of the membrane ， which
provides a long growth periodicity to low 2 growth 2speed germs in the reactor ， membrane biological reactors
CN11 - 2629 P X
© 1995-2005 Tsinghua Tongfang Optical Disc Co.， Ltd. All rights reserved.
can keep both good nitrification and high methane yields ( Chiemchaist ， 1993) .
In China ， the research of membrane reactor begins in 1990s. The research topics include treatment of
municipal wastewater (Li ， 1999) and oily wastewater ( Fan ， 1997) . Most research results ， however ， are
still in laboratory. Membrane reactors are composed of biological system and membrane system. Among
membrane components ， hollow fiber is the most widely used ( Yamamoto ， 1989 ; Zhang ， 1996) . Based on
the way of the combination ， they normally fall into two categories ， i . e. ， separated reactors and united
reactors as shown in Fig. 1 and Fig. 2 1 Separated reactors have independent biological system and
membrane system. Outlet of biological system goes into membrane component by a pump . Concentrated
solutions are back flow into the reactor. Penetrated water is let off as outlet . In united reactors ， membrane
components are immerged in the biological reactor. Outlet is normally let off through extraction. The
comparison of two kinds of membrane biological reactor is shown in Table 1 1