11 
interreg 
Baltic Sea Region 
JROPEAN 
Z6IQMAL 
*VELOPMENT 
It 
7 COMPLETE PLUS 
Table 4: Two approaches of IWC 
Approaches of IWC 
Usage 
Cleaning methods 
Proactive In-water Cleaning 
(PIC)/ Treatment (PIT)/ 
Cleaning and Capture (PICC) 
Used for prevention and 
reduction of microfouling 
(consequently macrofouling is 
prevented as well. 
The PICC system does not only 
capture the cleaned-off foul but 
also treats the effluent water. 
The cleaning can be conducted 
by using soft brushes, water 
jets, or contactless systems 
(Scianni & Georgiades 2019, 
3). 
Reactive In-water Cleaning 
(RIC)/ Treatment (RIT)/ 
Cleaning and Capture (RICC) 
Used for the removal of 
biofouling, especially when the 
prevention or removal of 
microfouling has failed and 
macrofouling developed. 
Another reason for the 
occurrence of macrofouling is 
damaged AFS. 
The cleaning methods include 
abrasive brush systems and 
high-pressure water jets. 
Since macrofouling is harder to 
remove, cleaning methods are 
more aggressive and might 
abrase the AFS into the aquatic 
environment presenting 
contamination risk (Scianni & 
Georgiades 2019, 5). 
As mentioned in chapter 2.1.1, previous studies demonstrated that aggressive cleaning 
techniques could significantly increase biocide emissions (Schiff et al. 2004). This is one of a 
number of reasons why proactive systems are to recommend over reactive systems. 
A study has shown that costs for IWC of oil tankers are lower for proactive cleaning than for 
cleaning ships in stages of hard and medium level of fouling which are usually treated with reactive 
sleaning systems. In every single scenario (21 in total), proactive cleaning was estimated to lead 
to higher annual savings (Stuer-Lauridsen & Kern-Nielsen 2021). 
Table 5 gives an overview of possible IWC methods in the Baltic Sea. Beyond that, this document 
does not aim to evaluate specific cleaning methods. AFS-manufacturers should specify which 
cleaning methods are most suitable for their coatings to prevent damage and therefore keep 
particle and hazardous substances input as low as possible 
18