=Paper=
{{Paper
|id=Vol-3293/paper34
|storemode=property
|title=Utilizing IoT Technologies to Reuse Treated Wastewater for Irrigation: A Precision Agriculture Pilot Case
|pdfUrl=https://ceur-ws.org/Vol-3293/paper34.pdf
|volume=Vol-3293
|authors=Malamati Louta,Dimitris Pantelakis,Fokion Papathanasiou,Thomas Kyriakidis,Konstantina Banti,Ioanna Karampelia,Sokratis Lappos,Evangelia Mpagkavou,Theodoros Adamidis,Ioanna Gkanatsa
|dblpUrl=https://dblp.org/rec/conf/haicta/LoutaPPKBKLMAG22
}}
==Utilizing IoT Technologies to Reuse Treated Wastewater for Irrigation: A Precision Agriculture Pilot Case==
https://ceur-ws.org/Vol-3293/paper34.pdf
Utilizing IoT Technologies to Reuse Treated Wastewater for
Irrigation: A Precision Agriculture Pilot Case
Malamati Louta 1, Dimitris Pantelakis 2, Fokion Papathanasiou 2, Thomas Kyriakidis 1,
Konstantina Banti 1, Ioanna Karampelia 1, Sokratis Lappos 3, Evangelia Mpagkavou 3,
Theodoros Adamidis 3 and Ioanna Gkanatsa 3
1
University of Western Macedonia, Department of Electrical and Computer Engineering, Karamanli & Lygeris,
Kozani, Greece
2
University of Western Macedonia, Department of Agriculture, Terma Kontopoulou, Florina, Greece
3
Municipal Enterprise for Water Supply and Sewerage in Kozani, 2nd km NR Kozani-Thessaloniki, Kozani, Greece
Abstract
The AUGEIAS project is expected to reduce the usage of conventional irrigation water and
fertilizers, promoting the sustainable use of treated wastewater, while properly incentivizing
farmers through the incorporation of an intelligent dynamic pricing scheme for its use. As part
of the project, a pilot installation of AUGEIAS was carried out in a chosen field for the
verification and optimization of the functionality of the AUGEIAS system. During the pilot,
IoT sensors were deployed in the field to evaluate its characteristics both with and without the
use of treated wastewater from the exit of the Waste Water Treatment Plant (WWTP). This
work presents the implementation plan for the pilot case of the AUGEIAS project. We will
discuss the functional requirements that led to cultivation of the proposed crop, the irrigation
plan and the required IoT equipment.
Keywords 1
Smart water management, treated wastewater re-use, precision agriculture, IoT, pilot case
1. Introduction
Water is a prerequisite for protecting public health and human well-being, while playing a critical
role in agriculture, industry and energy production. Only 3% of total water on earth is considered as
freshwater resources and approximately 30% is accessible as groundwater. Climate change in
conjunction with increasing urbanization, associated pollution and rising demand for agricultural
products will put even more strain to land, water, energy and other natural resources already stressed.
Thus, an efficient and sustainable management of water resources is urgently necessitated. Sustainable
water management can only be realized with rigorous evidence-based decision making. Information
and communication technologies (ICT), such as Internet of Things (IoT) [1] combined with wireless
sensor networks (WSN), low power wide area networks (LPWAN) [2], cloud computing, data analytics,
artificial intelligence [3], have the potential to efficiently support decision making process, laying the
foundations of a water smart society. At the same time, the viability of agro-livestock enterprises
demands their shift from maximizing profit to reducing production costs and improving product quality.
The integration of new information and communication technologies in the production process allows
the monitoring and recording of critical parameters, their processing and exploitation to generate new
knowledge and efficiently support decision making. This reduces total costs and reduces errors by
making possible a rational management of the production cycle.
Proceedings of HAICTA 2022, September 22–25, 2022, Athens, Greece
EMAIL: louta@uowm.gr (A. 1); pantelakisdim@gmail.com (A. 2); fpapathanasiou@uowm.gr (A. 3); tkiriakidis@uowm.gr (A. 4);
kbanti@uowm.gr (A. 5); i.karampelia@uowm.gr (A. 6); slappos@deyakoz.gr (A. 7); ebagav@deyakoz.gr (A. 8); adamidist@deyakoz.gr
(A. 9); ggan@deyakoz.gr (A. 10)
ORCID: 0000-0001-7340-1276 (A. 3); 0000-0001-5664-2473 (A. 4)
©️ 2022 Copyright for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR Workshop Proceedings (CEUR-WS.org)
172
To this end, smart management and re-use of up to now un-exploitable treated wastewater in
agriculture is important both in economic and environmental terms. Motivated by the above, AUGEIAS
develops an integrated intelligent ecosystem consisting of an innovative, easy-to-install and fully-
parameterized low power wide area network, IoT end-devices, which will provide real time
measurements from the wastewater treatment infrastructure and the agriculture sites, analyze and
correlate collected data with reliable open data (e.g. meteorological data), exploit advanced machine
learning techniques and predictive analytics in order to support informed decision making, optimizing
the usage of treated wastewater in a safe and efficient manner for agricultural purposes. AUGEIAS is
expected to reduce the usage of conventional irrigation water as well as of fertilizers, promoting
sustainable use of treated wastewater, while properly incentivizing farmers through the incorporation
of an intelligent dynamic pricing scheme for its use. Quality and quantity of crops is guaranteed by the
proposed AUGEIAS intelligent water management engine that defines the appropriate mixing ratio of
conventional water with treated wastewater, taking into account crop needs, soil status and imposed
legislation limitations.
2. AUGEIAS Functional Requirements
Nowadays, the use of treated wastewater in agriculture for irrigation is a widespread technique.
However, its usage has various risks associated with the composition of the treated wastewater and the
possible presence of pathogens, microorganisms and pollutants. Therefore, the quality characteristics
(microbiological, conventional and chemical) of the treated water must not exceed the safety limits set
by Greek legislation [4]. AUGEIAS monitors specific quality characteristics of the treated water in real-
time, while other are analyzed in a lab from samples taken at intervals specified by the relevant
legislation [4] for restricted irrigation, ensuring that the values are within set limits. Furthermore, it is
necessary to detect heavy metals contained in the treated water and the maximum safety limits [4] must
not be exceeded. In addition, AUGEIAS collects data to optimize the irrigation using treated wastewater
which are related to environmental / weather data, soil state, water safety and quality data as well as the
current soil and crop status.
Table 1
Recommended Guidelines for microbiological and conventional parameters for agricultural
wastewater reuse in Greece [4]
E. coli BOD5 SS Turbidity Minimum Minimum
(EC/100ml) (mg/l) (mg/l) (NTU) required Sampling
treatment Frequency
BOD5, TSS, N, P:
according to
a) Secondary CMD
25 for 35 for
Restricted biological 5673/400/97
≤200 median 80% of 80% of -
Irrigation treatment EC: one/week.
samples samples
b) Disinfection Cl2: continuous
(If chlorination is
applied)
3. Pilot Description
The pilot program will be implemented in a field located in north-western Greece, near the city of
Kozani and its WWTP, as shown in Figure 1.
The overall area of the field is about 0.35ha with the pilot area covering a total area of 0.128ha and
the selected crop being sunflower. The experimental plot is divided in three areas that will receive
different irrigation treatments. A first area of 0.045ha, will receive no irrigation, a second area of
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0.061ha will be irrigated with treated wastewater and the third area of 0.022ha will be irrigated using
conventional water from the town’s supply system.
Conventional
Non irrigated
water
= 0.045 ha
= 0.022 ha
Treated wasterwater
WWTP = 0.061 ha
Field
Figure1: The broader pilot area and a layout of the experimental sunflower field with the two
treatments irrigated (water from WWTP and water from the town’s supply system) and non-irrigated.
3.1. Field Characteristics
The terrain of the experimental field is sloping with a height difference of about 6% -10%. In the
upper part of the field, there are higher surface slopes which are directed towards to the middle of the
field, while in the lower part the slopes are reduced significantly, maintaining a uniform direction.
As far as the soil texture of the experimental field is concerned, two representative samples from
the upper and the lower part of the field were taken analysed. The soil is characterized as a Loam Clay
which is ideal for a sunflower crop. Τhe concentration of the organic substance in the soil is quite
significant but the salt concentration is significantly low. The soil pH is neutral to alkaline which is
ideal for the cultivation of sunflower. The high levels of calcium (high calcium carbonate concentration)
may create problems in the availability of certain trace elements while zinc and boron which are present
in the soil at low levels could be added to the required amounts by foliar fertilization.
3.2. Sunflower Cultivation
Sunflower (Helianthus annuus L.) was selected among other energy crops, such as sorghum or corn,
as the most economic and resistant crop which could be ideally adapted to the soil and climatic
conditions of the experimental area.
The sunflower crop has a relatively short developmental period of 100-150 days from sowing to
physiological maturation, depending on the hybrid, cultivation technique and usage (seed production or
animal feed). The plants are resistant to drought, except during the flowering period. On average, it
takes 6-10 days from sowing to germination, 30-40 days from germination to the appearance of the
inflorescence, 20-30 days from the appearance of the inflorescence to the beginning of flowering, 7-12
days from the beginning to the end of flowering and finally another 30 days from the end of flowering
to normal maturation [5].
3.3. Irrigation Plan
Two drop irrigation systems were designed to irrigate the sunflower crop. The first system will use
treated wastewater coming from the exit of the WWTP while the second system will use conventional
water from the town's supply system. When the water of the WWTP does not meet certain irrigation
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and quality standards then the two types of water will be mixed in a plastic tank in order to irrigate the
sunflower crop.
Generally, the drop irrigation systems were designed based on the irrigation needs of the crop, the
soil characteristics, the availability and the quality of the irrigation water. Based on this, the irrigation
systems will consist of several application pipes (external diameter 20mm), a distribution pipe (external
diameter 25mm) and a transmission pipe (external diameter 32mm) which will follow the soil slope.
Each irrigation network will have a pump and all the hydraulic equipment required for the proper
operation of the network.
According to the preliminary irrigation study, the irrigation of the sunflower crop will be repeated
every 4 to 5 days with 21mm of water and for maximum time of 7 hr according to the needs of the crop.
The total amount of the irrigated water is calculated at about 20m3 starting just before sowing if it's
necessary root moisture should be equal to the field capacity (FC).
Figure 2: Water balance of the root zone [6] (RAW=readily available water, TAW=total available water)
It is obvious that soil moisture and the irrigation plan will be affected by rainfall during the irrigation
season. The data coming from the meteorological station and the moisture sensors installed in the field
will use the Equation (1) that describes the water balance of the root zone (Figure 2), affecting the
irrigation schedule.
The daily water balance, expressed in terms of depletion at the end of the day is:
𝐷𝑆 = 𝑆2 − 𝑆1 = 𝑅 + 𝐼 + 𝐶𝑃 − 𝐸𝑡 − 𝐷 − 𝐷𝑃 − 𝑅𝑂 (1)
where 𝐷𝑆 is the change in soil moisture, 𝑆1 and 𝑆2 are the soil moisture storage at previous and at next
observation day, respectively, 𝑅 is the rainfall, 𝐼 is the irrigation, 𝐶𝑃 is the capillary rise, 𝐸𝑡 is the
evapotranspiration, 𝐷 is the drainage, 𝐷𝑃 is the deep percolation and 𝑅𝑂 is the runoff.
Rainfall, irrigation, and capillary rise of groundwater towards the root zone add water to the root
zone and decrease the root zone depletion. Soil evaporation, crop transpiration and percolation losses
remove water from the root zone and increase the depletion.
3.4. Required IoT Equipment
The project’s functional requirements led to the final selection of the IoT equipment required for the
pilot. Specifically, LoRaWAN sensors are installed both at the exit of the WWTP and in both parts of
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the field. Two external LoRaWAN gateways are used, within the coverage area of all end-devices. One
gateway is powered by a solar panel, while the other one has a constant power supply. We use the first
gateway to evaluate the performance of the novel energy efficient communication protocol that has
been developed and the second one as a backup. A processed quality measuring station has been
installed to measure the quality characteristics of the treated wastewater from the exit of the WWTP in
real-time. Quality is monitored, for the existence of disease-bearing micro-organisms (pathogens) such
as coliforms, biological oxygen demand (BOD), chemical oxygen demand (COD) and nitrates.
Moreover, additional water characteristics such as temperature, pH, oxidation-reduction potential
(ORP), conductivity, dissolved oxygen, turbidity, and total suspended solids (TSS) are measured. For
pollutants, such as heavy metals and organic materials, that cannot be measured in real-time by the
station’s sensors, the WWTP personnel takes samples at regular interval, and analyzes them in a lab.
Concerning the irrigated part of the field with treated water of WWTP, a station is installed
consisting of a meteorological station, a system for measuring soil parameters as well as an NDVI
measuring system. Specifically, the meteorological station measures air temperature, gust windspeed,
precipitation, relative humidity levels, solar radiation, wind direction and windspeed and soil
parameters such as conductivity, humidity and temperature at three different depths (5, 15 and 25cm)
respectively. An additional soil sensor has been installed in the part of the field that is irrigated with
conventional water, to monitor soil volumetric water content (VWC), temperature and bulk electrical
conductivity (ECb).
Finally, in order to better serve the needs of the project, an additional agrometeorological station of
the Telecommunication Networks and Advanced Services Laboratory (TELNAS) of the University of
Western Macedonia (UOWM) is also installed in the non-irrigated area of the field. This station
measures: air temperature, relative humidity, precipitation, windspeed, leaf moisture as well as soil
salinity, humidity, and temperature at three different depths (5, 15 and 25cm) respectively.
4. AUGEIAS Ecosystem Evaluation and Next Steps
AUGEIAS ecosystem aims to improve sustainable water management and reduce the waste of water
resources by using treated wastewater in agriculture. An immediate effect is the increase in profits for
both the WWTP managing authorities and the farmers, as well as the quality and quantity of the
production. Over-irrigation is also reduced by monitoring soil moisture and forecasting weather in order
to optimize the irrigation plan. Additionally, the nutrients contained in the treated wastewater, can
reduce the applications of fertilizers, that are typically used by farmers to improve the quality of crops.
The treated wastewater relevant subsystems, such as monitoring of characteristics, risk assessment of
the use of treated wastewater and possible mixing of treated wastewater with conventional water to
optimize production, will also participate in the second phase of the project. A single integrated
ecosystem will be implemented that will make real-time decisions regarding the irrigation needs of the
field, as well as the mixing and pricing of the treated water from the exit of the WWTP.
5. Acknowledgements
This research has been co-financed by the European Regional Development Fund of the European
Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship
and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code: T2EDK-04211).
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