One of the newest ballast water management systems on the market is aiming to make a splash in the high ballast dependent market.
Matt Hughes, executive vice president of sales for US-based EnviroCleanse LLC, was keen to discuss the advantages of the company’s inTank ballast water treatment system for high ballast dependent vessels during an interview with The Motorship.
USCG approval
“We have seen a strong pick up in orders since we obtained our USCG approval in February,” Matt Hughes said. The fleet order from Enterprises Shipping & Trading for over 30 vessels at the beginning of the year has been followed by others. “We have received orders from bulk carrier operators as well as for very large crude carriers and semi-submersibles.”
Hughes said that the growth was due to the particular operational advantages offered by the inTank BWTS. Pump rate requirements for high ballast dependent vessels, such as bulk carriers and oil tankers, can range up as 3,000 m3/hour for Capesize vessels, or 5,000 m3/hour for very large crude carriers.
The inTank system treats the tank during a vessel’s voyage, combining side stream electrochlorination with recirculation in the ballast tanks.
The design of the system ensures that the system’s peak energy demand is distributed during a vessel’s voyage, rather than during a vessel’s ballasting and de-ballasting process and potentially during cargo operations.
The inTank system’s energy requirements vary according to an individual vessel’s specific operating pattern including ballasted voyage duration, as well as ballast capacity, and the number of tanks to be treated. However, the circulation pumps and electrochlorination cells, which have an electrical efficiency of 4.5 to 6.0 kW per kg per hour of chlorine generated, are the most energy intensive parts of the BWTS.
Hughes cited the example of a 178,000 dwt bulk carrier which has booked an inTank installation in Q4 2019 with a treated ballast capacity of about 75,000 m3 and an owner specified minimum ballasted voyage time of 120 hours. EnviroCleanse specified a 12 kg/hour EC module and circulation pumps rated to move 270 m3/hour.
For this configuration, the expected power requirements are as follows:
Total peak: 237 kW
Total avg: 178 kW
Circ. Pumps Peak: 142 kW
Circ. Pumps Avg: 104 kW
inTank Peak: 92 kW
inTank avg: 71kW
Separation of functions
One of the advantages of the inTank BWTS is that it separates the treatment and ballasting functions.
While electrochlorination (EC) is the most economical way of handling the volume of water requiring treatment in high ballast dependent vessels, many other EC systems use neutralization during de-ballasting. Hughes noted inTank BWTS did not require neutralisation at the point of discharge.
This had advantages in terms of inTank’s space requirements, which are relatively small compared with other systems. The absence of neutralization also simplifies retrofit design, as no efficiency savings can be achieved by introducing different neutralization sub-assemblies in designs.
No filtration
One of the distinguishing features of the inTank BWTS is that it does not need to filter water during ballasting.
By applying Concentration Time, a metric used in the waste water industry, inTank™ also inactivates larger species and pathogens, removing the requirement for pre-treatment such as filters.
Employing a filter-free solution eliminates several potential issues associated with the use of filters. These risks include reduced ballast water intake, de-rated pumps due to saturation or even the shutdown of the filter mechanism.
Hughes noted that customers were very positive about the ability to ballast and de-ballast freely without running the risk of delay from filtration related issues.
The benefits also extended to accumulated mud and silt in the ballast tanks, which ship owners also have to ensure are treated properly.
inTank BWTS has proven to be effective treating organisms in sediment, as the re-application of disinfectant and in-tank mixing counteracts the ability of sediment to buffer chemicals.
Top side tanks on bulkers
Hughes also noted that a significant proportion of the bulk carrier fleet uses energy efficient top side water discharge tanks. These tanks often de-ballast directly overboard by gravity discharge. With the inTank solution the top side tanks are treated via a simple recirculation loop, using a section of the existing piping for suction to the dosing module whilst a new small diameter header is branched off for redelivery to each isolated top side tank.
As compliance is monitored for each individual tank in the circulation loop, treatment compliance for each of the tanks is confirmed before the water is discharged. As a result, the ships enjoy flexible to ballast and gravity de-ballast as required without any interruption in port.
