Volume 12 - 2010

The important advantage of zeolite applied to water treatment is its high porosity when comparing to
other minerals. The porosity results in good hydrodynamic properties (the increase in the pressure
loss on the zeolite filters is 1.5-2.0 times smaller than in the case of sand filters) and adsorption
roperties, and in turn high capacity which allows for adsorption of contaminants (a clinoptilolite filter
allows for removal of phytoplankton and bacteria).
The increase in the application of artificial fertilizers and gradual contamination of water resulted
from discharging industrial wastewater into the environment led to the contamination of the
environment by nitric compounds. Wastewater contains about 15-50 mg dm-3 of nitric compounds
(based on nitrogen) – ammonia salts constitute about 55-60% whereas organic forms of proteins,
pesticides and aminoacids about 40-50%.
Natural clinoptilolite could be applied to remove ammonium ions from water and wastewater. The
ammonium ion uptake behaviour of clinoptilolite is connected to the processes of ion exchange. The
main aim of this investigation is to evaluate the adsorption capacity of clinoptilolite towards
ammonium ions. According to the obtained results the adsorption capacity of clinoptilolite for the
removal of ammonium ions demonstrates its potential application in the treatment of water,
wastewater and sanitary landfill leachate contaminated with ammonia. The highest adsorption
capacity of clinoptilolite towards ammonium ions of 3.79 mg g-1 was found for the initial
concentration of 300 mg L-1. The highest removal level reached by clinoptilolite for ammonium was
of 99.74% for the initial concentration of ammonia of 50 mg L-1. The effect of exposure time on
maximum uptake of ammonia was found to be insignificant.

Activated carbon (AC) amendment for reduction of contaminant exposure in polluted soils and
sediments has recently emerged as a promising remediation technique. Here, we provide a short
overview of the state-of-the-art in activated carbon (AC) amendment to such sites. Most studies not
only in sediments but also in soils were carried out in the laboratory and only a few in the field.
Consequently, practical experience at the field scale is largely lacking, and feasible engineering
approaches for AC amendment still need to be developed, especially for soils. The effectiveness of the
AC treatment was evaluated by comparison of pollutant concentration reduction in the various
endpoints with those in the unamended control matrix. Endpoints in use comprise pollutant
concentrations in benthic organisms, depletive and non-depletive methods to quantify pollutant
exposures, as well as various toxicity endpoints of plants. Half of the studies in soils and 68% of the
studies in sediments showed reduced pollutant availabilities of >50% after AC amendment. Observed
low reductions (<50%) might be due to low exposure time, insufficient equilibrium time for coke
breeze, biochar, and granulated AC, overload of AC material, different uptake pathways of benthic
organisms, and pollutant reductions outside the dynamic range of toxicity endpoints. Further research
is needed to establish ideal AC amendment conditions to sediments and soils, leading to significantly
reduced pollutant bioavailability.

Composting of organic solid wastes is gaining in importance worldwide, in the frame of integrated
municipal solid waste management and, in particular, the diversion of biodegradables from
landfilling. At the post-consumer stage, this can be achieved by composting practices ranging from
large-scale facilities to home (or yard) composting. Increasing costs for final disposal of MSW also
point towards the use of composting technology as an alternative. This paper presents some results
and conclusions from various small-scale composting activities implemented in Hanoi and Manila
under different socio-economic settings, as well as a case study on a larger-scale composting
scheme in the Prefecture of Pieria, Greece in the frame of a 2-year joint research project. It focuses
on recommendations towards the Asian partners on how to improve their composting processes, on
the basis of reviewing and assessing current composting practices in Vietnam and the Philippines,
as well as some remarks on cost parameters for the Hellenic case study.

Discarded vehicle tyres constitute one important part of solid waste which had historically been disposed of
into landfills. Recent EU policies on the Landfilling of Waste (Council Directive 1999/31/EC) have however
put a ban on the landfilling of whole or shredded tyres, creating an imminent need to investigate any
possible viable uses of this waste product. An emerging use is the production of concrete, in which tyre
rubber particles partially replace natural aggregates. This has the additional advantage of saving in natural
aggregates used in the production of concrete which are becoming increasingly scarce. This research
investigated a wide range of physical and mechanical properties of concrete containing recycled tyre
aggregates, to assess its suitability as a construction material. The influence of factors such as rubber
aggregate content and size, as well as curing time was also considered. The results showed that despite a
great loss in strength, this type of concrete was acceptable for various applications requiring medium to low
compressive strength. The quantities of concrete produced worldwide for such applications could ensure
the viability of this product. Therefore, this type of concrete shows promise for becoming an additional
sustainable solution for tyre rubber waste management.