Euro-Mediterranean Project – Technical File: RUE / IN/ No. 14
General information
Project title:
Location
Code
Area
Year of approval
Sector
Programme
Reference no.
Advanced Desinfection and Health-Care Aspects of
Wastewater Reclamation and Reuse in Agriculture in
Mediterranean Regions
AVI-940010
Avicenne
Scientific officer: Prof. Lorenzo Liberti
1995
Avicenne
Co-ordinator, partners and suppliers
Organisation: Comunità delle Università Mediterranee
Organisation Type: Other
Address: Piazza Umberto I 1
Postcode: 70121
City: Bari
Country: ITALY
Telephone: +39-080 -5478.205
Fax: +39-080-5478.203
Contact person: Prof. LIBERTI
Other Contractors
Organisation Name: Institut Agronomique et Vétérinaire Hassan II
Organisation Type: Non Commercial
Department: Département de Biochimie
Address: PO Box 6202
City: Rabat
Org. Country: MOROCCO
Postcode: 10100
Organisation Name: University of Portsmouth
Organisation Type: Education
Department: Department of Civil Engineering
Address: Hampshire Terrace
City: Portsmouth
Org. Country: UNITED KINGDOM
Postcode: PO1 2EG
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Organisation Name: Universidad Autonoma de Barcelona
Organisation Type: Education
Department: Unitad d'Hidrogeologia - Facultat de Ciencies
City: Barcelona
Region: ESTE
CATALUÑA
Barcelona
Org. Country: SPAIN
Postcode: 08193
Organisation Name: Hebrew University of Jerusalem
Organisation Type: Education
Department: Environmental Science
School of Applied Sciences and Technology
Address: Givat Ram
City: Jerusalem
Org. Country: ISRAEL
Postcode: 91904
Organisation Name: University of Malta
Organisation Type: Education
Department: Department of Biology
Institute For Energy Technology
City: MSD 04 Msida
Org. Country: MALTA
Main supplier
1) UVT SPA-TARANTO
2) CILLICHEMIE, MILANO
3) SOLVAY, LIVORNO
Aims and objectives
- Comparison of different disinfecting technologies in terms of germicidal effect as
well as formation of harmful by-products;
- Investigation of health implications and waterborne disease spread out by partially
disinfected wastewater with special attention to epidemiological and toxic effects
on aquatic life and humans
- Evaluation of low-cost technology systems of wastewater treatment for
agricultural reuse appropriate to Mediterranean Countries
- Optimisation of schemes for wastewater utilisation in agriculture by reference to
crops, pedology, groundwater vulnerability, irrigation methods and management
aspects
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Situation of the project
Description
The research methodology was based on parallel investigations of various aspects
related to wastewater treatment, agricultural reuse and human health care. In particular
- Engineering and sanitary of advanced disinfecting: comparison of different
disinfecting technologies (i.e., ozone, chlorine, hydrogen peroxide, ultraviolet rays,
silver and other heavy metal ions) in terms of germicidal effect as well as
formation of harmful disinfecting by-products (DBP) formation carried out at pilot
and full scale
- Low-cost technology: high rate algae ponds that accounts also for heavy metals
content of wastewater evaluated ad pilot and field level. Optimisation of schemes
for wastewater reuse in agriculture by reference to crops, pedology, groundwater
vulnerability, irrigation methods and organisation
- Environmental impact on sea and ground water: impact of (partially disinfected)
wastewater direct discharge through marine outfall as well as reduction of
nitrification rate due to heavy metal
- Investigation of health implications and waterborne diseases: diffusion of
waterborn diseases and related pathogens in wastewater and detection of endemic
Mediterranean species and selected DBP and listed chemicals also related to nonEuropean immigration
Phase of advancement completed
Dates of beginning and conclusion: 01-02-95/31-01-98
Innovative technology: advanced disinfecting methods for safe wastewater reuse
Supplier Country: Italy, Milan; Italy, Livorno;UK, Warrington, Cheshire
Open field for photos and graphic material
O3P
P5
O3E
P3
P AA/
H2O2
P2
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FM2
O3M
P1
O3T
MF
RV
2
II
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P4
FM1
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4
CL
3
UVCP
UVA
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Results and achievements
The triennial project was concluded in February 1998, as scheduled. Experimental
results came from laboratory up to full scale demonstration plants purposely built in
Bari (Italy), Ouarzazate and Rabat (Morocco) and Bellaterra (Spain). All the planned
research activities and objectives were achieved to a satisfying extent (say, >80% of
expectation)- 100% achievement was prevented by lack of time, with at least 2 more
years being now considered necessary to confirm on a longer basis the project
outcomes in the best operating conditions evaluated. The experimental results of the
sanitary, agronomic toxicological and economic investigations performed can be
summarised as follows.
A. Alternative disinfecting technologies to chlorination
 The stringent microbial limit for unrestricted reuse of municipal wastewater in
agriculture (2 CFU/100ml Total Coliforms) were achieved through UV
disinfecting of either clarified or clarified-filtered secondary effluents with a dose
of 160 and 100 mWs/cm2 respectively (log-inactivation values  5). Similar results
with PAA required very high doses (up to 400 ppm and 20 min, log-inactivation
values  3) and were never achieved with Ozone in the conditions investigated.
 The corresponding WHO limit (1000 CFU/100ml Fecal Coliforms) was achieved
with all three disinfectants.
 All three disinfectants were very effective against bacteria like Pseudomonas
Aeruginosa. Parasites like Giardia Lamblia cysts and Cryptosporidium Parvum
oocysts were affected by UV radiation, while O3 was rather effective towards
Giardia only and PAA showed poor action towards such resistant pathogens.
 Harmful by-products were not detected after UV or PAA disinfecting, while
limited formation of aldehydes was evidenced during O3 disinfecting
 O&M costs range from 17.5 up to 2500 Euro/1000m3 for UV and PAA
disinfecting respectively (2 CFU of TC/100m1) and 37.5 Euro/1000m3 for O3
(1000 CFU of FC/ 100ml).
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UV disinfecting performance can be improved by hydrodynamics simulation and
laser measurements.
Two hrs exposure to H2O2 (100 ppm) + Ag+ (100 ppb), rather than to each one
separately, was moderately effective in inactivating model indicator bacteria
(log-inactivation 0.9 and 1.8 respectively).
Better inactivation occurred in similar conditions with H2O2 (30ppm) + Cu++ (100
ppb) (3 logs reduction).
Stress gene expression through bacterial luminescence revealed that H2O2 induces
a wide array of stress responses (DNA and protein damages) while Ag+ induces
stresses responding to protein damages.
Further investigation is recommended on:
 Synergy and/or catalytic effects of mixed disinfectants;
 more extensive search for potential DBP formation;
 laser measurements to investigate the hydrodynamic behaviour of UV systems;
 full scale cost evaluation;
 alternative disinfecting of municipal wastewater treated with low-technology
systems.
B. Health care aspects of wastewater disinfecting and reuse
 Experimental results support the hypothesis that chlorinated and untreated
effluents may generate long-term biological effects on ecologically important
species.
 Trihalomethanes (of which bromoform appears to be the most dominant one
although chloroform has been most extensively studied) are the major chlorination
DBPs and may exert a range of ecotoxicologic effects on marine organisms at
concentration above 0.01 mg/l.
 The whole area in the immediate vicinity of the sewage discharge from the Wied
Ghammieq outfall in Malta shows evidence of degradation. Modelling of plume
discharge and diffusion and LANDSAT remote sensing, indicated that the area
within which the levels of E. coli would exceed 100 CFU/100ml may extend up to
3 km from the discharge point.
 A systematic field investigation carried out in Apulia region (S.Italy) showed that:
- up to 10% of foodstuffs (vegetables, mussels etc.) and 20% of surface waters
(treated municipal effluents, marine coastal discharges etc.) exceed the
contamination limit of 100 MPN of TC/100 ml, with peak value up to 55% for
drainage canal waters;
- unproper agronomic practice and dietary habits, such as eating raw shellfish
and vegetables, make thyphus and hepatitis A endemic in this region, with 4.8
and 130 morbidity rates (cases per 100,000 inhabitants) respectively,
compared to 0.9 and 2.4 national averages.
- uncontrolled immigration from countries with endemic amebiasis, ascariasis,
trichocephalosis parasite-induced infections may further contribute to
spreading out of waterborne diseases in the absence of carefully planned
extensive prophylactic measures.
 A survey of chlorine DBPs in various environmental compartments in Malta
showed persistently detectable levels of bromodichloromethane in soil irrigated
with treated wastewater. Cauliflower had high levels of chloroform in most parts
of the plant, except in the flower, where bromoform was found to be predominant.
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 A similar study in Apulia region (S.Italy) focused on nitrosoammines and
nitro-biphenyls (DBPs potentially promoted by UV disinfection), Terra rossa soils
and artichoke (Cynara cardunculus L., scolymus) showed peak accumulatíon of
the nitrosamines after 4-5 days then decreasing to ground value within 12 days.
 To prevent excess nitrogen imported through wastewater recycling in agriculture to
leach into groundwater, efficient N-exporter crops were investigated in a Saharan
farmland near Ouarzazate (Morocco) irrigated with domestic wastewater.
Experimental results indicated that for both annual (maize and RGI) and perennial
(alfalfa) crops the amount of exported nitrogen is higher than that imported with
wastewater (approx. 780 kg N/Ha/year, i.e., 200% of N carried by the wastewater),
with Ouarzazate soil able to supply until 450 kg/Ha/year of nitrogen for crops.
Further investigation is recommended:
 to better characterize the biologic impacts of chlorinated and untreated sewage
related, in particular, to the ecotoxic properties of bromoform, allowing to obtain a
general picture of the biocenotic changes induced in marine environment;
 to evaluate bioaccumulation and subsequent biotransformation of DBPs in plants as
well as the health hazards associated with the observed concentrations in the edible
produce;
 to assess whether wastewater reuse can depend on crop rotation for preventing
nitrogen excess in soil and groundwater, as stated under Moroccan conditions.
C. Low technology wastewater treatment systems
 Developing Countries relay on low technology systems such as wastewater
stabilization ponds (WSP) that combine natural sedimentation, anaerobic
biodegradation and light penetration. In these systems singlet oxygen produced by
algal photosynthetic activity has been suggested, in addition to the well known
effect of pH increase during day-time, as a source of toxic-radicals that promote
Fecal Coliforms die-off. Such hypothesis underlies the need of increasing algal
cells concentration and counteracting the limiting effect of C02 on the algal
photosynthesis.
 To demonstrate the effect of maintaining an optimal algal cell concentration on
disinfecting in photosynthetic reactors, two High Rate Lagooning Systems (HRLS)
were compared to a WSP system at sub-tropical (Ouarzazate) and mediterranean
(Rabat) climates in Morocco and both HRLSs exhibited overall specific
disinfecting efficiency (CFU of FC removed/m2d) 1.5 times greater than WSP.
 To prevent the limiting effect of CO2 concentration, the biogas produced in the
HRLS anaerobic stage was injected into the maturation ponds in order to activate
photosynthesis and increase disinfecting efficiency, but this did not lead to finite
improvement.
 Several industrial effluents (tannery, tobacco, laundries etc.) were found to lower
the nitrification efficiency of wastewater treatment plants in Malta.
 Experimental investigation carried out at Bellaterra (Spain) on low cost processes
for the treatment of diluted (1:5) OMW (olive mill wastewater from olive oil
production) with A-Niger or P.Chrysosporium fungi and further inoculation with
different bacteria populations evidenced the biodegradation ability of these fungi
(60-70% COD reduction after 6-8 days of treatment).
 The inoculation of leachate from municipal solid waste sanitary landfill further
increased the bio-degradability of OMW and a combined process consisting of
fungi pretreatment of diluted OMW plus aerobic treatment with inoculum from
leachate yielded a total COD reduction around 90%.
Further investigation is recommended on the following items:
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introduction of advanced disinfecting methods (i.e., UV rays, Ozone) to go further
in reducing the FC concentration beyond the level normally reached in the
maturation ponds (around 750 CFU/100 ml);
use of membrane technology (ultrafiltration, nanofiltration, reverse osmosis) to
reduce the still considerable COD remaining in OMW treatment.
Co-operation data
Strict interaction was achieved throughout the project among the 6 cooperating
partners and, in particular, between Italy & Israel (disinfecting technologies), Spain &
Morocco (low-cost treatment methods), UK & Malta, plus Italy (DBPs and health care
aspects of disinfecting). Results dissemination was ensured through 25 original
publications and contributions to International Congresses and 17 dissertation theses
(BSc, MSc and PhD) originated so far from the project, with several papers being now
submitted to peer-reviewed journals.
In Italy, where the major part of the project was carried out, close cooperation
throughout the project was ensured by EAAP (Southern Italy Water Authority) as well
as by customers and industrial sponsors (these latter provided finite financial support
for building Bari’s 100 m3/h demonstration plant). As a matter of fact, on the basis of
project results, 17 full-scale new disinfecting plants (largely based on UV rays) have
been already installed and others are anticipated. Furthermore, 13 large Apulian
municipal wastewater treatment plants have substituted chlorination with UV
disinfecting in 1998-99. Similar industry sponsorship, although to a less finite
commercial level, was achieved also by Spanish, Maltesian and Moroccoan partners.
Major advancement came from the field comparison of competitive disinfecting
methods (UV rays, ozone, peracetic acid, hydrogen peroxide and oligometals opposed
to chlorine), of which both disinfecting mechanism and practical feature were
investigated to a reasonable detail.
Further investigation is recommended along the lines indicated.
Potential application
- Disinfecting plants based on advanced technologies (i.e. ozone, chlorine, hydrogen
peroxide, ultraviolet, rays, silver and other heavy metal ions)
- Low-cost technology wastewater treatment systems. Low-cost technology systems
of wastewater treatment for agricultural reuse appropriate to Mediterranean
countries such as high rate algae ponds that accounts also for heavy metals content .
- Plants for reduction of rates of nitrification in secondary treatment as result of
exposure to heavy metals
General comments
The approval of this triennial joint research project by the Commission of the
European Communities in December 1994 made the multinational research team
involved (from Israel, Italy, Malta, Morocco, Spain and United Kingdom under the
overall coordination of the Community of the Mediterranean Universities) feel proud
and anxious at one time, aware of the extent, complexity and timeliness of the multiple
objectives pursued.
Encouraged also by the CEC “excellent” rating of the project, a great deal of efforts
and strength was involved to face the task carrying it out to the best of the available
capabilities within the limited resources and the strict schedule assigned.
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The written output originated during the three years duration of this project includes
6 volumes (3 Yearly Progress Reports, Proceedings of 2 Workshops and Final Report)
totaling over 3,000 pages.
The experimental results and discussion, already presented to the scientific
community through 25 publications and contributions to international conferences, and
17 dissertation theses (BSc, MSc and PhD) related to this project discussed at the
participating Universities certify the upper-education activity performed so far.
The scientific, technical and economic value of the work carried out will be
evaluated by the scientific community, whose judgment is respectfully looked
forward. Among the results attained so far, however, the following ones in our opinion
made the project worth undertaking and, at least from a social-cultural point of view, a
real success:
- over 40 well reputed and long experienced scientists from 6 countries have
cooperated closely, working side-by-side for three years, meeting repeatedly in
brain-storming workshops, sharing eagerness, enthusiasm and, sometime, quarrels.
This has reinforced beyond expectation the existing cooperation in education and
research areas among the participating countries, in the very spirit of the CEC
Avicenne Initiative and the CMU;
- a lively network has been established that includes engineers, chemists, biologists,
biochemists, agronomists, geologists, hydrogeologists, zoologists and
parasitologists, who have learned how to improve sharing knowledge, skill,
investigation methodologies and even language in R&D with particular emphasis
to the safe and cost-effective wastewater reuse in agriculture;
- as acknowledged in detail in proper sections of this Report, in addition to several
scientific and technical institutions such as Italy’s NRC and Southern Water
Authority (EAAP), Malta’s Water Services etc., the industrial sector has also
provided a consistent support to the project on recognition of its ultimate interest
and the value of the investigation carried out. The cross-fertilization ensured in this
way among Academy, Research and Industry proved crucial for carrying out the
whole project on schedule and achieving its main objectives;
- the inheritage of this experience, including its hardware components such as, in
particular, the high rate algal pond and lagooning systems operated at Ouarzazate
and Rabat (Morocco), the bio-physico-chemical pilot plant for treating industrial
effluents at Bellaterra (Spain), the 100 m3/h tertiary pilot plant erected at West Bari
(Italy) etc., stands now as a precious tool for further investigation and refinement
of the difficult questions matched with this Project.
Contact person for further information
Name
Prof. LIBERTI Lorenzo
Telephone no.
+39-080-5460368
Telefax no.
+39-080-5460282
E-mail
liberti@poliba.it
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