2. the BWE suggests that fresh water organisms cannot survive in salt
water and vice-versa (Smith et al., 1999). So, BWE typically elimi-
nates between 70% and 99% of the organisms originally taken into a
tank while the vessel is in or near a port (Cohen, 1998). However, in
order to have a proof of the effectiveness of mid-ocean exchange,
the BW salinity must be examined. This test consists of collecting a
sample of the BW in the tank, dripping it in a refractometer or using
an electronic meter and analyzing the salinity and specific weight
of the sample. The result will confirm if the water collected origi-
nates from estuary, coastal or mid-ocean waters and will confirm
whether this water was exchanged in the open s ea.
Current methods to verify the real exchange of BW at conditions
established by the BWM Convention are limited to determining the
salinity (Duggan et al., 2005; Drake et al., 2002; Choi et al., 2005),
whilst it would be convenient if other parameters were also veri-
fied. For an onboard verification, tanks have to be opened and
samples collected (Gray et al., 2007), but there are many reported
problems concerning tank opening operations (Murphy et al.,
2003), such as the lack of inspection stations, as well as the lack
of specialized technicians to perform them. Another problem,
although not yet reported in the literature, involves the team
mobilization cost for this procedure. Alternatively, another method
for this verification is to use the coordinates submitted in the BW
reporting forms (BWRFs). From these reports, it is possible to
identify if the region of the BWE was at least 200 nautical miles
away from the coast and in waters at least 200 m (m) deep, the
basic demands for the exchange of BW (Pereira et al., 2014).
On the other hand, there is a problem associated with the reli-
ability of the information in the BWRFs that the ships have to
deliver to the Port State Control (PSC) before arriving at a port
(Pereira et al., 2014). In fact, in the specific case of Brazil, records of
BWE violations are not uncommon. Leal Neto (2007) presented the
main problems found in a survey conducted by the Globallast
Program, using forms delivered to the Brazilian Navy between 2001
and 2002. Caron Junior (2007) showed inconsistencies during the
analyses of 808 BW forms handed to maritime authorities of the
port of Itajaí-SC, in the south of Brazil. The Brazilian Health
Surveillance Agency (2003) conducted another study that shows
the results of 99 samples of BW in 9 Brazilian ports, revealing that
some ships had not exchanged the BW. However, the lack of con-
fidence of BWE also affects other countries. In fact, Brown (2012)
showed the non-compliance BW report in California. In the first
semester of 2012, approximately 1 million metric tons (MMT) non-
compliance BW was discharged in California ports, due to either
operational error or incorrect geography and not to intentional
mismanagement. In 2014, all ships that accessed the Great Lakes
had their tanks examined and BW samples were collected (Great
Lakes Seaway, 2015). Pereira et al. (2014) presented several prob-
lems with BWRFs delivered by ships to the Brazilian Navy in the
Amazon region, where it was identified that ships deballast in ports
in this region without conducting the BWE at sea. Additionally, it
was identified that these ships presented problems with the quality
of the BW inside their tanks.
Generally speaking, the BWRF does not provide information
about the quality of the BW captured by the ships. However, in-
formation of water characteristics, such as turbidity, salinity, dis-
solved oxygen (DO), pH and temperature, would be very useful for
the PSC to identify the quality of the water, especially because the
water collected in the ports may contain domestic, industrial and
agricultural effluents (Vandermeulen, 1996; Peterlin et al., 2005).
These water parameters can indicate the probability of surviving
species and treatment efficiency of the BW inside ship tanks. In fact,
some of these effluents may be highly polluting when discharged in
nature in the destination port environment. Among these constit-
uents of estuary waters can be found dissolved solids, salts, organic
sewage, nutrients, heavy metals, hydrocarbons, radioactive mate-
rials and herbicides (Clark, 1986) that are not identified with cur-
rent methods utilized to evaluate the quality of BW. Mainly, the
release of sewage into port regions can alter the pH and the de-
mand for DO in water, carrying the nutrients and promoting the
proliferation of toxic algae and the destabilization of the aquatic
ecosystem (Morrison et al., 2001).
In environments with high concentrations of organic matter,
such as algae, turbidity can be changed (Torgan, 2011). These
organic matters can be transferred into the BW tanks and can cause
problems such as red tide when discharged in other environments.
The change in turbidity can also occur in the presence of solid
“sand” in suspension (Prange and Pereira, 2013). The presence of
dissolved solids in the sea water tends to be higher than in estuaries
due to the low sea depth. Therefore, it is possible to find a large
amount of sand at the bottom of BW tanks (Prange and Pereira,
2013). Thus, the turbidity is indicative of the presence of several
organic and inorganic components that may be present in the BW
captured by the ship.
Since salinity may change from port to port, monitoring this
parameter may indicate whether there are risks of transfer species
due to the similarity between origin and destination ports. Other
factors associated with environmental similarity are water pH and
temperature, which can significantly impact the survival and sta-
bility of toxins produced by many organisms (Torgan, 2011). Thus,
the variation in the pH of the water collected and the water
exchanged by the ship can be an indicative of the probability of
surviving species in the ballast tanks. Besides, the presence of
dissolved gases in the BW can also indicate the probability of sur-
viving organisms and is related to the water temperature (Jewett
et al., 2005). For example, there are certain ranges of dissolved
oxygen (DO) in water (mg/l) that can be translated into survivability
of species. So, low DO levels are responsible for the death of many
organisms in BW (Tamburri et al., 2002).
As can be seen, in spite of the importance of different water
quality parameters to understand the effectiveness of BWE process,
only the salinity is evaluated when ships arrive at the port and
undergo BW inspection, with no other parameters reported by
ships in BWRFs. So, motivated by this, in this paper, we develop a
BW remote monitoring system (BWRMS) that collects, in real time
and directly inside the ballast tanks, the BW quality parameters.
This system includes sensors for turbidity, conductivity (salinity),
dissolved oxygen (DO), pH and temperature. An important char-
acteristic of this monitoring system is that the data from the sen-
sors are tagged with the ship's geographical position and the date
and time of the collection. The data are recorded in an unchange-
able electronic controller unit and remotely transferred via satellite
to an inland web server, where they can be analyzed. In that way,
the system allows not just monitoring and analyzation of the
evolution of water quality parameters but also independent veri-
fication of the geographical position where the BW is exchanged.
This can be done from the variations observed in the data collected
from sensors. Note that since the collected data are automatically
transmitted, the relevant information can be directly sent to the
port authority to validate the information in the BWRF, improving
its reliability and reducing or even removing the possibility of data
tampering. Even more, this can be the starting point for a new type
of electronic BW reporting form (e-BWRF).
This system was installed on the ship M/V Norsul Crateus (from
Norsul navigation company of Brazil) and has been in function since
April 2014, collecting BW parameters in the routes between the
ports located in South America (Argentina) and Brazil. In this paper,
we will present the validation of the system considering the data
from all voyages realized by the ship during the time between April
2014 and December 2015, where it is possible to compare the data
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3826
3. from BWRMS and the BWRF sent by the ship. We selected one
specific voyage to show a zoom the data collected from the BWRMS
and the BWRF from M/V Norsul Crateus. This voyage occurred from
Port of San Nicolas in Argentina (at Parana river) to Port of Santos
during the time between December 2014 and January 2015.
2. Materials and methods
2.1. System development
The development of the BWRMS was aimed at allowing for the
multipurpose use of the system. Therefore, the system should be
flexible and mostly adaptable mainly to the ship ballast operating
conditions. Fig. 1 presents the conceptual model of the system.
As can be seen in Fig. 1, the central component of the system is
the control unit, which collects data from the sensors, correlates
them with the vessel's geographical position (from GPS) at which
these data are collected and conditions all information to transmit
to an inland server via satellite communication. Since there is not a
commercial solution to attend to these requirements (collection
and transmission of sensors plus GPS data), a dedicated electronic
control circuit was designed and mounted.
The system includes sensors to measure conductivity, turbidity,
temperature, pH and dissolved oxygen, which were purchased
from Global Water Instrumentation. The sensors were selected to
monitor physical-chemical parameters and to perform measure-
ments in fresh and brackish water due to characteristics of fluvial
basins in Brazil. However, organic and biological parameters can
also be measured and sensors acquired from any supplier company
can be utilized (next step). The characteristics of the sensors are
presented in Table 1.
The vessel's geographical position coordinates are obtained by
means of a Global Positioning System (GPS) from GARMIN (model
GPS 17x NMEA 0183). To guarantee an autonomous functioning, a
solar energy-based power supply system was incorporated, of
which a proposal guaranteed the system's operation to be inde-
pendent of the ship's own power sources. For this purpose, a
photovoltaic solar panel captures sunlight and charges a 12 V bat-
tery, which, in turn, provides power for control units. This scheme
permits the system to operate without any crew interference and
preserves its integrity.
The system transmits the collected data using a Digi m10 mo-
dem and Orbcomm satellite constellation. The data are sent in bi-
nary format through messages to the available communication
satellite, which retransmits them to an inland server. Software was
developed to collect the data from the server and store them in a
database, from where they are accessible (via Internet) to the end
user. For this, we also developed a web-based graphic interface for
interpreting the numbers. In the results reported here, the collected
data are transmitted every 55 min, which seems suitable for this
type of study. However, this time is determined by the contracted
data transmission service and can be significantly shorter.
2.2. Ship installation process
The system was installed on the dry bulk carrier M/V Norsul
Crateus, IMO Number 9056399, from Norsul Navigation Company,
operating in Brazilian cabotage navigation. It has 42,487 DWT and a
BW capacity of 26,710 m3
. This ship also operates in the Amazon
basin and the River Plate basin, using fresh, brackish and salt water
during the ballast operation.
The BWRMS was installed on April 9, 2014, in the Port of Santos
(Latitude: 2387019.1200S, Longitude: 4637081.9700W) during the
unloading of iron ore cargo at a private terminal. The control
electronic system (control unit, data acquisition board and battery)
was placed inside a dust-proof, water-resistant case and installed in
the boatswain locker at the bow castle of the ship.
The sensors were installed in superior portside tank 1 A (ca-
pacity of ±600 m3
), one of the 14 ballast tanks of the ship. For
protection and mechanical support, the sensors were installed in a
stainless steel cage welded to the inside tank wall. This tank is close
to the forecastle and was selected due to the facility of sensor
installation (the tank is just below the deck), the proximity to the
boatswain's locker (the cable length is limited to around 30 m) and
Fig. 1. Conceptual model of the system installed in M/V Norsul Crateus.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e38 27
4. the fact that it performs BWE procedures every voyage.
To install the sensors, it was necessary to open small holes
(10 cm in diameter) on the main deck of the ship and on the wall of
the boatswain's locker of boatswain wall. Sets of stainless steel
flanges were welded on these accesses to pass through the sensor
cables and isolate the tank. These flanges include water feed-
through to guarantee the perfect impermeability of the BW tank
and the wall of the boatswain's locker.
Finally, the antenna, GPS, modem and solar panel were installed
at the top of the foremast, the base of which is just above the
boatswain's locker and the control system case, at a suitable dis-
tance to extend the data interconnection cables. During the
installation process, the stainless steel components were welded by
the ship's crew to fix the different parts of the system (sensor cage
in the BW tank, flanges on the main deck and the wall of the
boatswain's locker and solar panel at the foremast). A general view
of the installation of the BW monitoring system is shown in Figs. 2
and 3.
Fig. 3 shows some installation details of different parts of the
system. The entire installation process took around 16 h to be
concluded (from the initial presentation to the ship crew up to the
final turning on of the system) and directly involved 6 people.
2.3. Data evaluation
The data collected from the sensors are stored in a database
accessible via the Internet. In that way, the collected data can be
analyzed through a webpage that allows for selection of the period
Table 1
Characteristics of the sensors used to monitor BW quality.
Type of sensor Model Sensor range Sensor output Accuracy Power required
Conductivity WQ301 0e42000uS 4-19 mA 1% of full scale 10-30Vdc
Temperature WQ101 À50e50
C 4-19 mA ±0.1
C 10-36Vdc
pH WQ201 0e14 pH 4-19 mA 2% of full scale 10-30Vdc
Turbidity WQ730 0e50 0e1000 NTU 4-20 mA ±1% full scale 10-36Vdc
Dissolved oxygen WQ401 0-100% saturation 4-19 mA ±5% full scale 10-36Vdc
Fig. 2. General view of the BW monitoring system installed on the M/V Norsul Crateus ship.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3828
5. of time of interest and shows (over a map) the route of the ship
during this period. Small icon pointers on the route indicate the
exact position where the data are collected, and a dialog box shows
(in each pointer) the values measured by each sensor. Beside it,
graph windows show the variation of each parameter during the
entire requested period. A typical view of this web interface is
shown in Fig. 4.
Although it can be interesting as a first printout to observe long
periods of time, the interface shown in Fig. 4 is not very friendly for
that. In fact, due to the large amount of available data, the time of
the queue and port operation periods, the data observations can be
somewhat confusing. For these cases, the system offers the possi-
bility of exporting a data file (in Microsoft Excel format) for further
analysis.
3. Results
We present results from this development, reporting the steps
of the implementation and validation of the BW monitoring sys-
tem. Challenges are presented, showing how problems were solved
and the learning curve of this investigation. In the literature, a form
of BW monitoring with these characteristics was not yet reported,
nor was there this level of effort to build a specific and dedicated
solution for BWE compliance.
3.1. Initial measurements and considerations
At this moment, the BWRMS developed is continuously moni-
toring the tank parameters and has been since its installation in
April 2014, collecting data during the voyages for the BWE pro-
cedures and even when the ship is stationary at the port or in high
seas.
Although the system had been installed in April/2014, until
December/2014, we were just testing and adjusting the system
functioning. During this period, we experienced intermittent
problems with three sensors (temperature and pH) and with the
data transmission. In fact, after an in loco check-in, it was clear that
these problems were related to defective sensors and to failures in
the power delivery to the system.
The failure in the power supply was related to accumulation of
an opaque layer of sea salt aerosol and dust from ship iron ore
operation over the solar panel, which prevented efficient solar-to-
electrical energy conversion. Consequently, the battery-
recharging process was ineffective and, after a few days, the bat-
tery lost its charge and the system turned off. In the sequence, the
battery recovered a partial charge and the system turned on again,
in a cycle that repeated continuously and explained the observed
intermittent failures in data collection and transmission. This
occurred between May and October 2014.
Fig. 3. Details of the BWRMS installation in the ship: (A) cage of sensors inside the tank, (B) stainless steel flanges to pass through the cables of sensors, (C) system of protection of
cables, (D) control system installed in the boatswain's locker and (E) installation of antenna, modem and solar panel in the foremast.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e38 29
6. To overcome this problem, we could perform periodic cleaning
of the panel or even replace the panel with a bigger one with higher
power capacity. However, due to logistic and economic reasons, this
was not possible, and a simpler solution was to connect the system
to the main power energy of the ship. Note that this does not
represent a limitation of our system, since the photovoltaic panel
can be resized or installed in a cleaner place or a cleaner ship. Even
more, actually, the photovoltaic panel is actually not essential to the
BWRMS operation, and it was included just to guarantee a relative
autonomous operation to the ship crew. Regarding the sensors, we
had used them in the lab before installation on the ship. The pH
sensor worked only 8 days inside of the ship tank after the instal-
lation on board. The temperature sensor operated for 138 days. This
shows that the marine environment and the aggressive conditions
of the BW ship tank can make monitoring using water quality
sensors difficult.
3.2. System validation
After the energy problem was solved, the data from the BW ship
tank were more accurate. Therefore, we started to compare the data
between the BWRMS and the BWRF. The data from all the voyages
of the ship were plotted during the period from April 2014 until
December 2015. First, the data from ship voyages acquired from the
BWRMS were plotted on a ship timeline (blue line) in the horizontal
axis. Due to the decreases in pH and temperature, only the data
from sensors that were working during that time were plotted.
Each event relative to the ballast (red line), BWE (blue line) and
deballast (green line) operations were plotted in the vertical axis,
considering the date and time of the event reported in the BWRF.
From May to October, the system was unstable and data were lost,
and it was not possible to correlate that from the BWRMS and the
BWRF. Because of that, there is no vertical line that represents the
BW operation from the ship. We divided the period of analyses in
two figures. Fig. 5 presents the results collected during the first year
of system operation, from April 2014 to April 2015.
We could note that the BWRMS detected variations in BW
quality during the ship's voyages in the first year. All vertical lines
with a register of BW operation by the ship were identified from the
BWRF's. After the BWRMS installation, the BW tank was ballasted
with water from the Port of Santos, and the system started the
operation. During the time period between April 2014 until
December 2014, this ship ballasted only with sea water
(conductivity ¼ 42,000, mS ¼ 30.2 psu in 20 C).
On 25 December 2014, a ship ballasted in the Port of San Nicolas
(PSN) (located in the Paraguay-Parana waterway - Latitude:
3335009.5600S, Longitude: 6017054.1500W) in Argentina to go to the
Port of Santos (PS). Because of that, the conductivity reduced from
42,000 mS to 15,000 mS (9.8 psu), and the turbidity changed from 72
NTU to 212 NTU, that being a characteristic of fluvial rivers.
The ship arrived in PS on 01/05/2015 and deballasted, and bal-
lasting again at PS. The BWRMS detected a variation of BW quality
on 01/08/2015, but the BWRF showed that BWE had occurred on
01/07/2015. The BWE occurred near of Montevideo city, in Uruguay
(Latitude: 3498068.0500S - Longitude: 5457054.4700W). At this
point, the salt water salinity is influenced by the flow of fresh water
Fig. 4. Typical view of the web user interface developed to analyze the data collected from the BW monitoring system. The users can make a query in function of the specific period.
Data are sent to the server in 1-h intervals and are plotted in the interface, showing the ship's route and the geographic coordinator with graphics of the sensors' readings.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3830
7. from La Plata Basin, which reduces water salinity, making it
brackish water (Piola et al., 2005).
Therefore, the conductivity sensor showed a reduction in similar
readings in the last voyage and an increase in turbidity. In this case,
the ship deballasted in PSN. The ship ballasted again in PS on 01/28/
2015, where it is possible to note a variation of water turbidity in
relation to previous water in the tank. Until 03/19/2015, all BWRFs
showed that the ship ballasted in the Port of Santos, BWE in mid-
ocean and deballasted in PSN, but the conductivity value was sta-
ble in same value read where it could indicate eventual sensor
reading problems. However, the turbidity and DO showed varia-
tions correlated with BW events detailed in the BWRF.
After 03/19/2015, the ship moved to the Ponta da Madeira Ter-
minal (TPM), in Maranh~ao State (Latitude: 0256065.0900S, Longi-
tude: 4441015.1400W), and realized the BWE at 03/22/2015 near
Macae City in Rio de Janeiro State (Latitude: 2203090.0000S,
Longitude: 4041030.0000W). The ship deballasted in TPM and
moved to Port of Usiba Terminal (TPU) in Bahia State (Latitude:
1282057.5700S, Longitude: 3849088.8200W), where it ballasted and
moved to Shipyard Enavi in Rio de Janeiro (Latitude: 2285088.5600S,
Longitude: 4310059.0100W) to dock (Fig. 6).
According to the BW registers of the first year, we could note
that during the ship's voyage on the sea, the BWE was realized close
to the Brazilian coast, as shown in Table 2. These data were collect
by the BWRF and compared with the BWRMS to identify whether
BW quality suffered alternations in these positions. Distances were
calculated with Google Earth®
Fig. 5.
In the second year, the ship made voyages around the Brazilian
coast, concentrated in the northeast region. The ship was docked
between May and June. During this period, the readings from the
conductivity sensor showed variation while the ship was at the
shipyard. It was impossible to determinate the real causes of this
effect. The temporal series of the second year is presented in Fig. 7.
Over the period of 07/01/2015 until 10/23/2015, all ship ballast
operations occurred in the Amazon region. The ship operated be-
tween the Port of Alumar (PA) in Maranh~ao State (confluence be-
tween Estreito dos Coqueiros and the River of Cachorros near the
S~ao Marcos Basin e Latitude: 0267’.79.3800S, Longitude:
4436010.2000W) and the Port of Trombetas (PT) in Para State (in
Trombetas River - Latitude: 0145.5006800S, Longitude:
5639.8907500W), and during all voyages, the ballast occurred in PA.
Only on 08/23/2015 did the ship ballast in PA and deballast in
the Port of Juriti (PJ) in Para State (Latitude: 0217044.7600S -
Longitude: 5611030.6000W). On 10/23/2015, the ship ballasted in PA
and moved to TPM, where it deballasted on 10/28/2015. As the ship
was in the same region the BWE was not performed.
The last ballast operation occurred at TPU, on 11/13/2015, when
the ship was ballasted with salt water, but the conductivity sensor
did not identify this variation in the salt water. In this period, all
BWE operations usually occurred when the ship was entering the
Amazon river, which has a low salinity and high turbidity.
On the other hand, we could identify that similar turbidity
values were identified by Alc^antara et al. (2010); Affonso et al.
(2011) considering the measurements in situ during all seasons
throughout the year in Amazon rivers. DO measures showed values
higher than the first year of monitoring. This is a characteristic of
Amazon rivers, and similar DO values were measured by Quay et al.
(1995) in terms of DO saturation. These values suggested that due
to the Amazon water characteristics, the oxygen utilization rates
continue inside of the tank for some period of time during the
ship's voyage, as a cycle process that is always activated when a BW
operation occurs. This effect was also observed in Johengen et al.
(2007) while the BW tanks were monitored and several registers
of BW reoxygenation inside of the tanks occurred. During the first
year, the ship did not ballast in Amazon rivers, and the DO level is
lower than in August and October 2015.
Fig. 5. Register of ship voyages and BW operation, from April 2014 to April 2015. The horizontal line (blue) represents the sensors' reading. Vertical lines represent the BWRF events
(red -ballast, blue - BWE and green - deballast). Some ballast events occurred on the same date where the ship deballasted/ballasted in the same point. Because of that, red and
green points appear nearby with a time delay. Each BWE event is numbered above in sequence of occurrence (blue numbers). (For interpretation of the references to colour in this
figure legend, the reader is referred to the web version of this article.)
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e38 31
8. In the northeast of Brazil, it is warmer than in the southern
region, where the ship had made most of its voyages during 2014.
Because of that, the DO could be influenced by the temperature
inside of the ship's tank. Johengen et al. (2007) observed the in-
fluence of low temperatures on DO measurements inside of BW
tanks.
Our measurements presented that data from turbidity and DO
were adherent with the BWRF operations reported during the
course of the investigation. When the BWRF information was
compared with the information from the BWRMS, sometimes a
small variation occurred in the times reported in the BRWFs and the
BWRMS. This occurred because the ship crew could register the BW
operation time differently than was detected by the system or it
could also be due to some delay of data transfer.
To identify where the BWE's occurred, Fig. 8 and Table 3 present
the analysis of the BWE positions realized by the ship in the second
year informed by the BWRF.
Table 3 shows that the interval of the BWE operation was
reduced because the ship made short voyages during this period,
concentrated in the same region.
To evaluate the system validation by one specific voyage, Fig. 9
presents details of BW operations detected by BWRMS during a
voyage from the Port of San Nicolas to the Port of Santos between
12/25/2014 and 01/05/2015 and compared the accuracy of the
system to the BWRF information.
Fig. 9 shows that the ship ballasted in PSN and deballasted in PS.
The BWRF information was coherent with the sensors reading and
presented evidence that BWE had occurred in this voyage. This
example demonstrated that it is possible to verify the BW quality
inside of the tank before the ship's mooring. Additionally, the BWRF
information can be verified and correlated with the place, time and
date of the BWE reported. In this voyage, the ship did not realize
Fig. 6. Position of BWE's informed by BWRF detected by BWMRS. Brazil map shows the region where the ship was operation during these voyages.
Table 2
First year observations of BWE position by the BWRFs considering the sequence of voyages in a temporal series for ballast event (red line).
Voyage Date Coordinate Local Distance of coast
nautical miles
1 4/14/
2014
Latitude:32
02’.61.6000
S Littoral of Rio Grande do Sul e South Atlantic Ocean 48.22
Longitude:50
580
83.8000
W
2 11/14/
2014
Latitude:28
39’.0000
S Littoral of Santa Catarina e South Atlantic Ocean 13.92
Longitude:48
40'.0000
W
3 12/13/
2014
Latitude:28
340
54.0000
S Littoral of Santa Catarina e South Atlantic Ocean 9.8
Longitude:48
370
24.0000
W
4 1/7/
2015
Latitude:29
430
80.0000
S Littoral of Rio Grande do Sul e South Atlantic Ocean, but the BWRMS detected water quality variation at
Latitude: 34
980
68.0500
S, Longitude: 54
570
54.4700
W in 1/08/2015
31.34
Longitude:49
230
20.0000
W
5 2/1/
2015
Latitude:26
420
39.4000
S Littoral of Santa Catarina e South Atlantic Ocean 52.14
Longitude:47
420
91.6000
W
6 2/18/
2015
Latitude:24
570
60.0000
S Littoral of Sao Paulo e South Atlantic Ocean 56.22
Longitude:46
460
70.0000
W
7 3/22/
2015
Latitude:22
030
90.0000
S Littoral of Macae City in Rio de Janeiro State 22.89
Longitude:40
410
30.0000
W
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3832
9. Fig. 7. Register of ship voyages and BW operation from April 2015 to December 2015. The horizontal line (blue) represents the sensors reading. Vertical lines represent the BWRF
events (red e ballast, blue e BWE and green e deballast). Each BWE event is numbered above in sequence of occurrence (blue numbers). (For interpretation of the references to
colour in this figure legend, the reader is referred to the web version of this article.)
Fig. 8. Position of BWE's informed by BWRF detected by BWMRS. Brazil map shows the region where the ship was operation during these voyages.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e38 33
10. that BWE and brackish water was discharged in the estuary of
Santos. This happened because the ship was transporting brackish
water to be discharged in a salt water environment. Then, it
generated an osmotic stress, where the fresh and brackish species
cannot survive in salt water.
On the other hand, the conductivity sensor reading presented a
delay in identifying the change of BW quality. This suggests that
either this sensor could be influenced due to the latest operation
only being in salt water or the sensor quality not being able to
detect high variations of conductivity in a short time. We verified
similar events in other voyages in the northwest region during the
second year.
However, the turbidity sensor reading changed at the same
point indicated by the BWRF. The turbidity values for the Lower
Parana River near San Nicolas are about 30e230 NTU (Vazquez
et al., 1998), and for this voyage, the sensor read similar values.
The DO sensor reading concentration rates in the San Nicolas region
were similar to those identified by Casco et al. (2014), and it de-
pends on the year's seasons and temperature influence.
The variation of the sensors reading could be due to the acrylic
box utilized to keep the sensors wet all the time. Because of that, it
was impossible to verify the period in which the BW tank was
empty. This box can accumulate more organic matter and influence
the behavior of the sensors' reading, but it shows that there is an
organic dynamic inside of the tank during the ship's voyage.
When the tank was empty, sensors were reading only the pa-
rameters inside of the acrylic box from the cage of sensors.
Another aspect is that when the BW tank is empty, the liquid
accumulated inside of the box tends to be in motion during the
ship voyage. In this condition, there is reoxygenation and gases
inside of the tank that are in contact with liquid and sediments
accumulated on the bottom of the box that can influence the
sensor readings.
4. Discussion
We have reached the main objective of this study of the
development of a system able to validate the BWRF information
compliance. It then shows that it is possible to monitor the BW
quality inside of BW tanks and correlate correctly the real position
where the BWE was performed by the ships. This is an efficient way
to avoid occurrences that were reported in various studies (Junior
Caron, 2007; Leal Neto, 2007; Brown, 2012; Pereira et al., 2014)
and control the quality of BW discharge in sea and fluvial ports.
Considering that a BW treatment system that reaches the Cali-
fornia standard does not exist (Commission, 2014) and they did not
test the real condition to eliminate pathogenic species (Cohen and
Dobbs, 2015), the BWE then continues being an efficient alternative
to eliminate invasive species in BW tanks while a universal stan-
dard is not defined.
For this reason, BWE monitoring and BWRF information
compliance are ways to guarantee that ships are realizing the BWE
in the correct geographic position and discharging water following
the IMO standard. With this system, this verification can be done
during the entire time of the voyage of the ship, and it can be
compared with the BWRF information sent by ships to the Mari-
time Authority. It is an independent form to assist the PSC and
environmental agencies in monitoring the quality of the BW dis-
charged in their ports and making decisions about the acceptance
of the ships in the port. During algae bloom and BW operation at
night, it is possible to identify whether the BW tank is loading
water with high turbidity at sea.
However, installing and controlling a BWRMS is not simple, and
challenges are present in the installation of sensors inside of BW
tanks, controlling the sensor durability, system maintenance, the
quality of data gathered and the validation of BWRF information.
Similar challenges were reported in previous attempts to
monitor BW presented by Johengen et al. (2005, 2007). Some of the
problems and the results in this study can be compared in terms of
BW quality monitoring inside of BW tanks of the ships Irma and M/
V Lady Hamilton.
However, the proposal of both studies is the monitoring of BW
tanks, while the main difference between these studies refers to the
development of a particular solution for the remote BW moni-
toring. In these previous studies, the authors had installed a con-
ventional quality water instrument to evaluate water parameters.
This application did not allow that sensor readings were ob-
tained in real time. Johengen et al. (2005, 2007) also presented that
the GPS data collected had poor quality and could be used in
conjunction with water measurements by instruments. Then, data
from master's ships that reported the BW operations were then
used to compare with the data collected by sensors with BWE. In
our case, we could identify the position where BWE occurred only
by observing the BW quality alteration in the web interface, which
shows the ship's geographic position with water quality graphics
for each parameter monitored.
The process of BW monitoring can be done without any
participation of the ship's crew. In this previous case, the authors
reported that whenever the ship's crew was solicited to monitor
the water quality using some instrument, this operation failed. In
one event, the equipment was damaged, and this shows that utility
of the BW remote monitor. In our case, the ship crew was involved
only in the system installation. After that, the system operation
occurred independently, without the ship's crew.
Table 3
Second year observations of the BWE positions.
Voyage Date Coordinate Local Distance of coast nautical miles
8 7/17/2015 Latitude: 01
60
95.0000
N In Para State near the mouth of the Amazon river e northeast Atlantic Ocean 80.91
Longitude: 48
310
91.6000
W
9 7/28/2015 Latitude: 01
010
50.0000
N In Amapa State near the mouth of the Amazon river e northeast Atlantic Ocean 78.4
Longitude: 48
250
30.0000
W
10 8/20/2015 Latitude: 00
530
0.0000
N In Amapa State near the mouth of the Amazon river e northeast Atlantic Ocean 7,84
Longitude: 49
510
47.2000
W
11 8/31/2015 Latitude: 01
10.900
0000
N In Amapa State near the mouth of the Amazon river e northeast Atlantic Ocean 46
Longitude: 49
13’.80.0000
W
12 9/14/2015 Latitude: 00
50
28.4700
N In Amapa State in the Amazon river at Macapa city e northeast region 0
Longitude: 50
57’.70.0000
W
13 9/29/2015 Latitude: 01
110
2.2000
N In Amapa State near the mouth of the Amazon river e northeast Atlantic Ocean 38,2
Longitude: 49
19’.75.0000
W
14 10/11/2015 Latitude: 01
080
30.0000
N In Amapa State near the mouth of the Amazon river e northeast Atlantic Ocean 21,75
Longitude: 49
31”.80.0000
W
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3834
11. The other aspect is that the water quality instrument was
installed directly in the tank and did not suffer any influence from
the acrylic box inside of the cage of sensors. However, the obser-
vations were similar in terms of high turbidity of BW when the ship
was operating in river waters and low in sea water.
In these cases, ships that have been ballasting in rivers present
more probability of accumulating sediments inside of tanks. In this
way, our acrylic box was very sensitive to collected sediments, and
we observed this during the ship's visit to sensors' maintenance. In
regards to the conductive sensors, the range of the scale was higher
and allowed for monitoring of high values in terms of BW salinity
(ppt) than this study using the bottom of the scale in salt water.
During the first year of monitoring, the ship ballasted more in sea
water than in fresh water. It is obvious that it was associated to the
Fig. 9. Register of ship voyages and BW operation from 12/25/2014 to 01/05/2015.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e38 35
12. ship market's demand for transport.
This ship has been operating only in the cabotage routes in
Brazil, and the ballasting/deballasting always occurred close to the
coast. In contrast to ships that operate in marine navigation,
cabotage ships will usually deballast near the coast and regions
where the BW can be mixed with brackish and fresh water.
The monitoring of the ship's deballast position from cabotage
navigation can assist the PSC in determining the better region to
conduct this operation. The decision to realize the BWE is from
master ships that will evaluate where they can start this operation.
Our measure calls attention to this operation on the Brazilian coast
and probably has to be the same in other countries. It is associated
with operation cost, distance between call ports and time to com-
plete a travel. Then, it is natural that the cabotage ship will sail near
the coast region and will conduct the BWE operation in this region.
For example, in the Amazon region, the river can reach more than
200 km into the sea, and water will be mixed with sea water.
Because of that, the remote monitoring of BWE is important and
can map the more common area of ship BW discharge during the
exchange operation. Considering this characteristic and full-time
monitoring of BW quality inside of the tank for a long period of
time, the results were not examined in previous studies.
On the other hand, considering the period during which we
have been monitoring the BW tank, it is in fact a very aggressive
environment with some air and illumination limitations.
This condition has a great influence on sensors' durability and
generates a difficulty of maintenance. It could be confirmed due to
the short time of operation of the temperature and pH sensors
inside of the BW tank.
It is then necessary to consider that a ship completes many
travels during the year in different ports and routes. To conduct the
BWRMS repair, it took three visits in total to detect problems with
the solar panel and solve the energy failure to correct the operation
of the system. During this period, sensors failed, and due to the lack
of data transfers, we could not identify the cause of the sensors'
reading problems. This showed that the sensors' maintenance could
be a great challenge for correcting the operation of this system.
Additionally, we believe that the closed cage of sensors can
affect the results of the sensors' readings, considering that some
sediments, salt, organic matter and other compounds can be
deposited in the bottom. The sensors' quality can also affect the
data gathered and the satellite service. We tested only one supplier
of sensors, and other types and suppliers can be used in this
operation. For example, Raid et al. (2007) utilized a multi-
parameter instrument probe from YSI 6600EDS but opted to use
separate sensors and to construct our monitoring solution applied
specifically to BW tanks. Another challenge to the BWRMS opera-
tion is sensor calibration, which has to be done frequently and
substituted when necessary. It has to obligate the manager of this
operation to create a program of inspection and cleaning for the
sensors.
Another point that can influence the sensors' reading is the
ship's motion and external environment's conditions. Our results
show some alterations during the temporal series of water quality
that could be altered due to the acrylic box during the ship's motion
in bad weather conditions. One solution to solve this problem will
be remove sensors of box and inserting an accelerometer sensor to
read the ship's motion and correlate it with the BW quality. The
temperature sensor mainly represents the external environment's
influence above the BW tank during the ship's voyage. In the course
of the first measure with this sensor operation, we were able to
note some alteration in pH and DO levels with tank temperature
variation.
Even with these challenges presented, the BWRMS demon-
strated that it is possible to monitor the BW quality remotely, and
this can be an advantage of BWM when compared to current
methods to evaluate the BWRF compliance. Moreover, this BW
remote monitoring can assist us in understanding the BW quality
dynamic inside the tank. When the monitoring is punctual, the
temporal series of quality variation inside of the tank can be lost. To
understand this behavior, it is necessary to monitor the tank
constantly.
Associated with this, during the ship's voyages, data collected in
several ports can create a port water-quality database to validate
the BWE operation in coastal ports.
Thus, the system was developed to allow for the coupling of
eight sensors, but this can be expanded so that a single control unit
may monitor all the ballast tanks of a ship through the addition of
sensors and A/D converter units. The modem, GPS and satellite data
transfer systems are located in an external area of the ship. There is
no need for multiple control units if one means to measure data
from all the ballast tanks. In this case, it is better to place the A/D
converter units close to the ballast tanks. Thus, a single pair of ca-
bles can run along the ship to transmit data from all ballast tanks to
the control unit. The prototype includes a data acquisition unit in
the hermetic booth, but this is not an essential requirement; it was
used for simplicity purposes.
The equipment for capturing solar power was not able to pro-
vide the system with sufficient power to operate during the ship's
entire voyage. We do not recommend the use of solar panels in this
application, and it is necessary to use the ship power supply. The
system did not create any interference from other ship systems.
More specifically, this solution presented can assist the Brazilian
PSC, which needs to control ships that have been operating in more
than 100 port terminals installed in coastline and fluvial basins. The
Brazilian coastline has an extension of 7,408 km and several ports
with different water quality. Hereby, it can be applied in other
countries located in several parts of the world, as an efficient BW
treatment system has not been developed.
Brazil is divided in eight fluvial basins composed of big rivers,
where some of them can receive ships from cabotage that conduct
BW operations. For example, in the La Plata, Uruguay and Paraguay
Rivers and the Patos Lagoon system, the famous Limnoperna fortune
(golden mussel) was introduced by BW from ships (Uliano-Silva
et al., 2013). Depending on ship cabotage routes, they can move
into these fluvial basins to load and unload cargo, where the BW
discharge may occur. This can be examined considering the ship
routes monitored in this investigation.
Ships that ballast in fluvial ports will probably deballast in sea
ports in the course of coast littoral or in fluvial ports located on the
Amazon and Para rivers, in the northeast region of Brazil. Therefore,
the control of the BW quality inside of the tanks is a great indicator
for inhibition of transfer of invasive species for other regions in this
country. In this investigation, we identified that this ship has been
exchanging BW as recommended by Brazilian regulation.
5. Conclusion
We concluded that this system is able to monitor whether ships
are operating according to IMO recommendations, performing the
operation of BWE at least 200 nautical miles from the nearest land
in water, at least 200 m' depth.
This investigation identifies that this cabotage ship performed
BWE operations near the Brazilian coastline and also at least 50
nautical miles from the nearest land in waters of at least 200 m
depth. This has been occurring due to ship routes that have a lower
operation cost for the ship. Some BWEs occurred in the Amazon
region when the ship was operating in Para and Maranh~ao States
inside of the Amazon river or near its mouth, which was indicated
in the past for the Brazilian Navy in NORMAM 20/2005.
N.N. Pereira et al. / Ocean Coastal Management 131 (2016) 25e3836
13. In January 2014, the Brazilian Navy changed the previous
regulation and published the NORMAM 20/2014, which removed
the obligation of a second BWE for cabotage ships' entrance into the
Amazon region, and ships do not need to change their route to
attend to the request of at least 50 nautical miles. This study can
then alert the IMO and PSC about the risk of transferring invasive
species, because ships can ballast in rivers and deballast into the
same macro fluvial region in short voyages, as had occurred in the
Amazon region. Thus, marine and fresh water species can be easily
adapted to new regions, since they are in the same macro region
where the water characteristics are similar.
On the other hand, the BW monitoring system presented is able
to reduce mistakes in the BWRF as well as to provide more reli-
ability in the information given to Port State Control than those
reports presented by the ship crews in the paper form. Our results
show that ship correctly conducts the BWE, as informed in the
BWRF. The graphic interface developed to read data sent by the
system can be easily adapted to receive data from the acquisition
system and to convert them into a BWRF. Herewith, the PSC can
receive BWRF information with more reliability with inclusion of
BW quality parameters.
Furthermore, this system can generate cost reductions for ship
ballast inspection operations from PSC. Ship BW quality data can be
received remotely before the ship arrives at port areas. In fact, the
BW remote monitor inside of the ship tanks is a great challenge to
be implemented on a large scale. Several problems can affect the
efficiency of this system, such as power energy supply using solar
panels, data transmission, sensor reading quality and data inter-
pretation, ship tank access and the sensors' maintenance interval.
Even with these difficulties, we evaluated the BWE operation by
physical-chemical parameters variation and identified the correct
position for BWE. This allows us to conclude that salinity is usually
the main parameter in determining the BWE, but depending on the
water quality, the changing in turbidity can also be a good indicator
of whether there has been monitoring in the BW. Sensors with high
sensitivity can indicate small variations, which can be compared
with BWRF information. Usually, the turbidity is not indicated with
a BWE indicator, even in the BWM Convention. Thus, if ships have a
BWRMS onboard, port authorities can use the turbidity to validate
the BWE.
Acknowledgement
We would like to acknowledge Norsul, a Brazilian shipping
company, for giving us this great opportunity to install the BW
monitoring system in the M/V Crateus. The ship's crew was essential
during the installation process. This study was financed and sup-
ported by the Brazilian National Council of Scientific and Techno-
logical Development - CNPq (558151/2009-4) and the Brazilian
Innovation Agency e FINEP (0112016800). We specially acknowl-
edge Prof. Dr. Rui Carlos Botter for contacts with ship companies to
install our system, as well as naval engineer Geert Jan Prange, who
helped us conceive this system, and Alexandre Tavares Lopes to
help us in this development and ship installation.
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