Challenges to implementing a ballast water remote monitoring system

Ocean & Coastal Management 131 (2016) 25e38

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Challenges to implementing a ballast water remote monitoring system
bio Belotti Colombo c, Marco Isaías Alayo Cha
vez c, Newton Narciso Pereira a, *, Fa b c
ez Carren ~o Hernani Luiz Brinati , Marcelo Nelson Pa a

Department of Production Engineering, School of Industrial Engineering Metallurgical Volta Redonda (EEIMVR-UFF), Av. dos Trabalhadores 420, Room C77- Vila Sta. Cecília, 27255-125, Volta Redonda, Rio de Janeiro, Brazil b ~o Paulo, Av. Luciano Gualberto, 2230, 05508-030, Sa ~o Department of Naval Architecture and Oceanic Engineering, School of Engineering, University of Sa Paulo, SP, Brazil c ~o Paulo, Av. Luciano Gualberto, 2230, 05508-030, Sa ~o Paulo, SP, Brazil Department of Electronic System Engineering, School of Engineering, University of Sa

a r t i c l e i n f o

a b s t r a c t

Article history: Received 29 February 2016 Received in revised form 21 June 2016 Accepted 19 July 2016

In this paper, we describe a ballast water data logger system to monitor the ballast water exchange and the water quality contained in ship tanks. This system is able to register physical-chemical parameters of ballast water by using sensors for measuring turbidity, salinity, dissolved oxygen, pH and temperature. Those data are tagged with the geographical position (GPS), date and time at which the ship operates its ballast system and are remotely transferred via satellite transmission to an Internet server. The system was installed on the ship M/V Crateus (from Norsul Navigation Company) and has been functioning since April 2014, collecting ballast water quality parameters in the routes between Argentina and the north region of Brazil. From the collected data, the system proved to be able to identify the ballast water exchange along the ship's journey, allowing for independent verification of information provided by the crew in the ballast water reporting form. As an additional advantage, this information can be automatically transmitted to the port authorities, improving the reliability of this information and reducing, or even removing, the possibility of data tampering. Nowadays, the salinity is the main indicator to determinate whether a ship makes the ballast water exchange. However, we identify that water turbidity can be one more indicator to identify the ballast water exchange that could be recommended by the International Maritime Organization. © 2016 Elsevier Ltd. All rights reserved.

Keywords: Ballast water Monitoring Ports Water quality Pollution Invasive species

1. Introduction The introduction of exotic species in port areas is currently a great environmental problem in several parts of the world (Cohen, 1998; Cohen and Foster, 2010; Pereira and Brinati, 2012), and this was first reported by the International Maritime Organization (IMO) in 1973 during the creation of the International Convention for the Prevention of Pollution from Ships - MARPOL 73/78 (IMO, 2004; Cohen and Foster, 2010). In the course of the convention, Resolution 18 for Research into the Effects of Discharge of Ballast Water containing Bacteria of Epidemic Diseases was approved, which charged the IMO with the responsibility for elaborating measures of ballast water (BW) control (Cohen, 1998). In fact, since 1994, several exotic species have been identified in many parts of the world (Hallegraeff, 1992; Carlton and Geller, 1993; Gollasch,

* Corresponding author. E-mail address: [email protected] (N.N. Pereira). http://dx.doi.org/10.1016/j.ocecoaman.2016.07.008 0964-5691/© 2016 Elsevier Ltd. All rights reserved.

2006), and studies have identified BW as the vector of exotic species transfer (Ruiz et al., 1997). Therefore, the impact caused by the organisms found in BW, such as Vibrio cholerae (Dobroski et al., 2009; Cohen and Dobbs, 2015), can be of great important for marine environment, the economy and human health. The first initiative taken by the IMO to deal with this problem was to establish Resolution A.868 (20) in 1997, which recommends that ships perform ballast water exchange (BWE) in open sea. In 2004, the International Convention for the Control and Management of Ships' Ballast Water and Sediments (BWM Convention) took place, with the purpose of establishing guidelines for BW control (IMO, 2004). BW operations normally occur while ships are unloading cargo in ports. In the port regions, the salinity varies between 32 ppt and 35 ppt (parts per trillion), although it can be higher or lower in some specific cases (Murphy et al., 2008; Doblin et al., 2010; Cohen and Foster, 2010). On the other side, in open ocean, the salinity varies, on average, from 35 ppt to 37 ppt (Murphy et al., 2008). Thus,

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the BWE suggests that fresh water organisms cannot survive in salt water and vice-versa (Smith et al., 1999). So, BWE typically eliminates 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 originates 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 verified. 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 reliability 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 confidence 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) noncompliance 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 problems 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, information of water characteristics, such as turbidity, salinity, dissolved 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 constituents of estuary waters can be found dissolved solids, salts, organic

sewage, nutrients, heavy metals, hydrocarbons, radioactive materials and herbicides (Clark, 1986) that are not identified with current methods utilized to evaluate the quality of BW. Mainly, the release of sewage into port regions can alter the pH and the demand 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 stability 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 surviving 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 characteristic of this monitoring system is that the data from the sensors are tagged with the ship's geographical position and the date and time of the collection. The data are recorded in an unchangeable 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 verification 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) 25e38

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
river) to Port of Santos Port of San Nicolas in Argentina (at Parana 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 measurements 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 independent of the ship's own power sources. For this purpose, a

27

photovoltaic solar panel captures sunlight and charges a 12 V battery, 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 modem and Orbcomm satellite constellation. The data are sent in binary 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: 23
87019.1200 S, Longitude: 46
370 81.9700 W) 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 (capacity 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.

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Table 1 Characteristics of the sensors used to monitor BW quality. Type of sensor

Model

Sensor range

Sensor output

Accuracy

Power required

Conductivity Temperature pH Turbidity Dissolved oxygen

WQ301 WQ101 WQ201 WQ730 WQ401

0e42000uS 50e50
C 0e14 pH 0e50 0e1000 NTU 0-100% saturation

4-19 4-19 4-19 4-20 4-19

1% of full scale ±0.1
C 2% of full scale ±1% full scale ±5% full scale

10-30Vdc 10-36Vdc 10-30Vdc 10-36Vdc 10-36Vdc

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 feedthrough 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 distance 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

mA mA mA mA mA

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

Fig. 2. General view of the BW monitoring system installed on the M/V Norsul Crateus ship.

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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.

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 possibility 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 system. 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 monitoring the tank parameters and has been since its installation in April 2014, collecting data during the voyages for the BWE procedures 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-toelectrical energy conversion. Consequently, the batteryrecharging process was ineffective and, after a few days, the battery 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.

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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.

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 installation 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-Paran
a waterway - Latitude: 33
350 09.5600 S, Longitude: 60
170 54.1500 W) 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 ballasting 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: 34
980 68.0500 S - Longitude: 54
570 54.4700 W). At this point, the salt water salinity is influenced by the flow of fresh water

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31

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.)

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 midocean and deballasted in PSN, but the conductivity value was stable in same value read where it could indicate eventual sensor reading problems. However, the turbidity and DO showed variations correlated with BW events detailed in the BWRF. After 03/19/2015, the ship moved to the Ponta da Madeira Ter~o State (Latitude: 02
560 65.0900 S, Longiminal (TPM), in Maranha
0 00 tude: 44 41 15.14 W), and realized the BWE at 03/22/2015 near
City in Rio de Janeiro State (Latitude: 22
030 90.0000 S, Macae Longitude: 40
41030.0000 W). The ship deballasted in TPM and moved to Port of Usiba Terminal (TPU) in Bahia State (Latitude: 12
820 57.5700 S, Longitude: 38
490 88.8200 W), where it ballasted and moved to Shipyard Enavi in Rio de Janeiro (Latitude: 22
850 88.5600 S, Longitude: 43
100 59.0100 W) 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~o State (confluence between the Port of Alumar (PA) in Maranha tween Estreito dos Coqueiros and the River of Cachorros near the ~o Marcos Basin e Latitude: 02
67’.79.3800 S, Longitude: Sa
State (in 44
360 10.2000 W) and the Port of Trombetas (PT) in Para Trombetas River - Latitude: 01
45.500 6800 S, Longitude: 56
39.890 7500 W), 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 Par
a State (Latitude: 02
17044.7600 S Longitude: 56
11030.6000 W). 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 ^ntara et al. (2010); Affonso et al. values were identified by Alca (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.

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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

Latitude:32
02’.61.6000 S Longitude:50
580 83.8000 W Latitude:28
39’.0000 S Longitude:48
40'.0000 W Latitude:28
340 54.0000 S Longitude:48
370 24.0000 W Latitude:29
430 80.0000 S Longitude:49
230 20.0000 W Latitude:26
420 39.4000 S Longitude:47
420 91.6000 W Latitude:24
570 60.0000 S Longitude:46
460 70.0000 W Latitude:22
030 90.0000 S Longitude:40
410 30.0000 W

Littoral of Rio Grande do Sul e South Atlantic Ocean

48.22

Littoral of Santa Catarina e South Atlantic Ocean

13.92

Littoral of Santa Catarina e South Atlantic Ocean

9.8

2 3 4 5 6 7

4/14/ 2014 11/14/ 2014 12/13/ 2014 1/7/ 2015 2/1/ 2015 2/18/ 2015 3/22/ 2015

Littoral of Rio Grande do Sul e South Atlantic Ocean, but the BWRMS detected water quality variation at 31.34 Latitude: 34
980 68.0500 S, Longitude: 54
570 54.4700 W in 1/08/2015 Littoral of Santa Catarina e South Atlantic Ocean 52.14 Littoral of Sao Paulo e South Atlantic Ocean

56.22


City in Rio de Janeiro State Littoral of Macae

22.89

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 influence 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

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33

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.

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N.N. Pereira et al. / Ocean & Coastal Management 131 (2016) 25e38

Table 3 Second year observations of the BWE positions. Voyage

Date

Coordinate

Local

Distance of coast nautical miles

8

7/17/2015

In Par
a State near the mouth of the Amazon river e northeast Atlantic Ocean

80.91

9

7/28/2015

In Amap
a State near the mouth of the Amazon river e northeast Atlantic Ocean

78.4

10

8/20/2015

In Amap
a State near the mouth of the Amazon river e northeast Atlantic Ocean

7,84

11

8/31/2015

In Amap
a State near the mouth of the Amazon river e northeast Atlantic Ocean

46

12

9/14/2015


city e northeast region In Amap
a State in the Amazon river at Macapa

0

13

9/29/2015

In Amap
a State near the mouth of the Amazon river e northeast Atlantic Ocean

38,2

14

10/11/2015

Latitude: 01
60 95.0000 N Longitude: 48
310 91.6000 W Latitude: 01
010 50.0000 N Longitude: 48
250 30.0000 W Latitude: 00
530 0.0000 N Longitude: 49
510 47.2000 W Latitude: 01
10.900 0000 N Longitude: 49
13’.80.0000 W Latitude: 00
50 28.4700 N Longitude: 50
57’.70.0000 W Latitude: 01
110 2.2000 N Longitude: 49
19’.75.0000 W Latitude: 01
080 30.0000 N Longitude: 49
31”.80.0000 W

In Amap
a State near the mouth of the Amazon river e northeast Atlantic Ocean

21,75

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 Paran
a 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 depends 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 parameters 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 California 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 standard 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 Maritime Authority. It is an independent form to assist the PSC and environmental agencies in monitoring the quality of the BW discharged 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 monitoring. In these previous studies, the authors had installed a conventional quality water instrument to evaluate water parameters. This application did not allow that sensor readings were obtained 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.

N.N. Pereira et al. / Ocean & Coastal Management 131 (2016) 25e38

35

Fig. 9. Register of ship voyages and BW operation from 12/25/2014 to 01/05/2015.

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 observations 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

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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 complete 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 multiparameter 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 operation 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 demonstrated 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 cables 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 provide 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
rivers, in the northeast region of Brazil. Therefore, Amazon and Para 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
and Maranha ~o States region when the ship was operating in Para 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) 25e38

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 reliability 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 interpretation, 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 supported by the Brazilian National Council of Scientific and Technological Development - CNPq (558151/2009-4) and the Brazilian Innovation Agency e FINEP (0112016800). We specially acknowledge 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. References Affonso, A.G., Queiroz, H.L.D., Novo, E.M.L.D.M., 2011. Limnological characterization
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