The International Maritime Organization (IMO) has passed the International Convention on the Control and Management of Ballast Water and Vessel Sediments, to regulate ballast water treatment systems (BWMS) and minimize the risk of spreading harmful aquatic organisms.
Hanla IMS has developed an EcoGuardian eco™ system to treat invasive aquatic organisms. The treatment method is to separate the electrolyzed current partly so that the system can customize installation near or far from the pipe. EcoGuardian™ system can be installed separately, leading to minimize the relocation of other equipment and optimize space.
Main features of ballast water treatment system – Eco Guardian – Ballast’s Water Management System (BWMS)
- Filter with automatic washing function, can filter organisms or solids larger than 50 μm
- Automatic washing when the pressure difference between the filter input and output is detected
- Automatically separate the current from the main pipe then the electrolysym is TRO (Total Oxidation Residue). THE ASH is then pumped back into the pipe to kill microorganisms.
- Electrolysis parts (including electrolytic cells, resizers/transformers, pressure pumps, conductive in touch devices and deoxation devices) produce sodium hypochlorite solutions that disinfect bottom organisms, pathogens, larvae or spores.
- The neutral unit adds sodium thiosulfate solution to the treated ballast water to neutralate the ASH excess during ballast flushing.
- Tro concentration reaches a maximum of 9.0 mg/L when ballast is performed
- Maximum TRO concentration of 0.2 mg/L when ballast discharge is performed
- Control system including PLC, HMI and anth aid equipment
System Overview:
Hanla EcoGuardian ballast water treatment system can be divided into the following 3 cycles:
- – Ballasting
- – During voyage
- – De-ballasting
Ballasting
- During the pumping of water into the ballast tank, the water is automatically filtered to the creatures and solids >50μm. This filter unit is installed directly into the main pipe.
- From the main road, water is partly branched through the electrolyked part, where electrolysed water produces sodium hypochlorite in high concentrations. The water is then re-pumped into the main pipe to continue into the ballast tank. This concentration reaches a maximum of 9 mg/L TRO with Cl2, it is controlled by the TRO continuous measuring sensor, i.e. EcoGuardian system™ which controls electrolytic current based on the return signal of the TRO sensor.
- EcoGuardian’s electrolytic ™ is designed to work with water with salinity of 10 PSU or more. In the case of low salinity water, the vessel can use water from the onboard water tank, since the system uses very little water (only about less than 5% of the water in the main pipe)
- A by-product of electrolysing is hydrogen gas, which is an explosive gas, so it needs to be separated as soon as possible after electrolysm. Hydrogen gas is separated by a centrifumatic and is reduced to less than 1% by blowing air in. Eventually Hydrogen was led out of the ship. The lower explosive limit of Hydrogen is 4%Vol, so applying a safety level of 4 times is appropriate.
During voyage
- The microorganisms in the ballast tank continue to be treated because residual ions after electrolyses remain for long periods of time.
De-ballasting
- During the pumping of water out of the ballast tank, the water simply passes through the neutral unit to treat the residual amount of ASH. The neutrale used is the common sodium thiosulfate, it will be sprayed and blended with water in the pipe. Sodium thiosulfate injections are controlled by monitoring flow rate and residual ASH concentration.
- Two TRO sensors are used to measure residual TRO concentrations at two points, before and after the unit is neutral. The TRO sensor before the neutral unit is used to measure the remaining TRO concentration and then the EcoGuardian controller ™ determines the amount of neutrals inserted into the tube. The TRO sensor remains after neutrality to check if the water has been properly neutral and the system adjusts itself if necessary.
- EcoGuardian’s neutral unit™ maintains a maximum allowable concentration [Maximum Allowable Discharge Concentration (MADC)] of 0.2 mg/L TRO for Cl2. To comply with this condition, the sodium thiosulfate dosage is established based on the stoichiometric ratio of TRO to sodium thiosulfate at a ratio of 1: 2. Sodium thiosulfate is pumped into the system so that residual TRO in water is quickly neutral neutral by the mixing effect on the pump wing wheel.
Video describing the system:
See more ballast water management systems here
Related Post
