vol 77 n° 5 2011 - Office International de l'Eau

STUDII SI CERCETARI
socio-political reception of sewage sludge recycling
A comparison of water service
charges as a proportion of net personal
income with consumption
per head, however, showed that
increasing family income does not
reduce average consumption below
80 l/person/day. This relation is
shown in figure 1.
In the 10 years since these statistics
were produced, a new phenomenon
has made its appearance
– non-payment of water charges.
We will return to this issue later.
The steady tightening of wastewater
treatment emission levels
has mainly involved the nitrogen
and phosphorus nutrients.
In response,
there have been improvements
in the efficiency
of wastewater
treatment technology,
causing an increase in
the unit costs of sludge.
The costs of treating
communal sludge
in Hungary vary between
€20 and 40 (dewatered
sludge with 18-25% dry
matter content). This includes the
cost of removal and treatment of
the sludge, but not the costs of
handling it within the wastewater
treatment plants.
2.
Aspects peculiar
to Hungary
Hungary’s wastewater system
has developed very rapidly in recent
years. This shows up very
clearly from the 31% increase in
the number of households connected
to the drainage system in
the last twenty years. Starting from
41% in 1990, it has reached 72% in
2010, fulfilling the European Union
requirement for every system to
terminate in a wastewater works
providing at least biological treatment.
[3]
The construction of the necessary
wastewater systems and treatment
works was given a powerful
boost by support from both EU
and government funds. Towns
and villages in Hungary are spread
across a relatively wide population
spectrum. Budapest stands well
table 1: Distribution of Hungarian population by
size of town [4]
apart, and is followed by four
large cities. Villages with less than
2000 inhabitants are very numerous
but account for only 17% of
the country’s population. [4]
Owing to the low population density
in such villages, unit drainage
costs are very high. At the same
time, the municipalities can only
turn for support to national funding,
which results in the choice
of local treatment solutions, without
a wastewater drainage system.
Regulation of these treatment
solutions is a current task at national
level.
The EU-supported objectives
of the National Wastewater Programme
for 2015 are:
- By the end of 2015, level II
(biological) sewage treatment must
be provided in conurbations of
between 10,000 and 15,000 PE, and
by this time at the latest in conurbations
of 2000-10,000 PE.
- By the end of 2015, artificial
biological or equivalent treatment
works must be set up in every
wastewater drainage agglomeration
smaller than 2000 PE which
lies in a designated hydrogeologically-sensitive
area.
The places where these developments
have to be completed
thus face crucial choices of sewage-treatment
and sludge-management
technology in the next five
years.
3. Changing
reception of
sludge-management
options
There have been major changes
recently in processes and machinery
for dewatering sludge. Processes
which were difficult to operate
or required much labour, such
as sludge beds or simply spreading
wet sludge on to agricultural land,
have given way to mechanised technologies
with high energy-consumption.
Improvements in dewatering
technology have achieved
higher and higher levels of dry
matter content, reducing the costs
nr.5 / 2011 www.romaqua.ro
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