dramatize水污染处理文献综述英文

2021年1月20日发(作者：misunderstanding)
Application
of
multi-soil-layer
system
(MSL)
in
rural
wastewater treatment

Abstract:

with
the
continuous
improvement
of
living
in
rural
farmers,
the
water
consumption
of
residents
is
increasing,
rural
sewage
emissions
will
continue
to
increase,
if
not
treat
effectively,
the
water
environment in rural areas will be serious deteriorated, and influence the
life
quality
of
rural
residents.
In
this
case
this
paper
presents
a
decentralized
sewage
treatment
system,
multi-soil-layer
system
technology
(MSL)
application
in
the
rural
sewage
treatment,
this
paper
summarizes the new technology, you can better understand and practice,
especially in the developing countries where is in need of this technology.
In the foreseeable future, it can protect public health and the sustainable
development of the environment, and it also provides a new way for rural
sewage treatment.
Key words:
rural sewage; multi-soil-layering system; distributed







1.

Introduction
In
recent
years,
with
the
continuous
development
of
economy,
people's
living
standards
continue
to
improve,
rural
economic
development is also very rapid, but the rural economic development and
environmental
development
is
not
synchronized,
serious
rural
water
pollution.

While
high
technical
sewage
treatment
plants,
such
as
centralized sewage treatment plants are involved in large investment costs,
high operating costs,

Because of economic constraints, such systems are
less
suitable
for
livestock
farms
and
small
communities
in
rural
areas.
While the multi-media-soil layer system(MSL) sewage treatment system,
this
decentralized
sewage
treatment
system,
it
has
less
investment,
low
operating costs, high handling load. Besides, the utility model overcomes
the defects of the prior soil percolation which is easy to be blocked from
the
space
structure.

The
sewage
treatment
system
is
one
kind
of
the
purification technology of sewerage treatment soil developed in Japan in
twentieth Century, the soil system will be modularized, and the module is
set
up
around
the
water
in
the
soil
layer
to
avoid
clogging,
and
adding
natural
organic
materials
to
soil
modules
can
improve
the
purification
ability of the system.
The
MSL
system
consists
of
a
Permeable
layer
(PL)
and
a
soil
mixing layer block (SMB),

The Permeable layer is usually composed of
larger particles fillers such as gravel, pumice, perlite and zeolite.

Higher
porosity
can
effectively
prevent
clogging
of
the
soil
water
layer.

At
the
same time, the formation of aerobic environment is conducive to organic
degradation.

The mixed layer soil is mainly packing soil mixed with other
20%-30% other materials such as activated carbon, wood, iron and other
material
or
soil
with
local
resources.

The
organic
material
added
in
the
soil
mixed
layer
can
improve
the
biological
decomposition
and
adsorption
capacity
of
the
system,
and
can
also
improve
the
supply
of
hydrogen in the process of nitrogen removal and promote the removal of
nitrogen.
There
are
many
researches on
MSL system
treating
urban
sewage,
livestock wastewater and river water at home and abroad.

Researchers in
China, Ye Hai et al
[1]
studied the effect of surface load on polluted river
water
treated
by
multi-soil-layer
system.

Song
Ying
[2]

had
studied
the
treatment
effect
of
multi
medium
soil
infiltration
system
for
turtle
breeding
wastewater.

Zou
Jun
[3]

also
pointed
out
that
multi- soil-layer
material
selection
will
have
a
certain
impact
on
the
domestic
sewage
treatment
efficiency.

In
foreign
countries,
especially
in
Japan,
Thailand
and Indonesia, MSL systems have been used to handle various types of
wastewater,
but
the
domestic
of
this
technology
in
sewage
treatment
in
rural
areas
there
is
no
comprehensive
study,

This
article
through
to
the
MSL
system
technology
processing
rural
domestic
sewage
research,
in
order
to
provide
some
technical
support
for
the
MSL
system
in
the
practical application of rural sewage treatment.

2.1characteristics of rural sewage
For
a
long
time,

China's
pollution
control
on
rural
attention
and
investment
far
less
than
the
city,

96%
of
the
villages
without
drainage
pipe
network
and
sewage
treatment
system,

The
random
discharge
of
domestic
sewage
has
become
one
of
the
main
reasons
for
the
deterioration of water quality in the basin, and is also an important factor
causing the rural water environment pollution and lake eutrophication.

At
the same time, it seriously affects the safety of production and living in
the rural areas, and seriously affects the economic development.

The main
features of rural sewage in China are:
(1)

The amount
is huge
and
increases
year
by
year.

Statistics show
that
in

are
3.205
million
tons
of

national
rural
domestic
sewage daily emissions.

The total nitrogen emission is about 283.1t, total
phosphorus daily emission is about 56.6t, basically without any treatment
directly discharged.
(2)

Water
quality
and
water
quantity
fluctuation
are
huge.

Rural
sewage water is not stable, different periods have different water quality,

generally do not contain heavy metals and toxic and harmful substances,
but contains more synthetic detergent and bacteria, viruses.