1.Disinfectants currently being used aboard ships and offshore structures have become sophisticated to the point where it is difficult for operators to distinguish their suitability for use with marine biological sewage treatment systems. One class of disinfectants is being increasingly used in cleaning compounds and it threatens the ability of certified marine sewage treatment systems to meet USCG, MARPOL and VGP 2013 regulations in service. These are quaternary ammonium compounds, commonly referred to as quats, a handier name than n alkyl dimethyl benzyl ammonium chlorides for example. Quats can be found in toilet bowl cleaners, dishwashing detergents and rinses, floor cleaners and laundry products, all being used or capable of being used aboard ship. Because of the substantial dilution of toxic chemicals in municipal sewage and the much higher concentrations to be found aboard ship, it is very possible for a biological process to pass the certification test but not operate reliably in service. Even though the certification test protocol requires concentration of total suspended solids from the more dilute municipal sewage to the minimum required by marine regulations, that does not affect the low concentrations of toxic chemicals in the sewage. As use of chlorine has declined, alternate disinfectants have proliferated in various cleaning agents, rinses, etc. Among these are quaternary ammonium compounds (QAC for short). Unlike chlorine, QAC and others are not oxidizing agents that are neutralized upon reacting with organic matter in sewage. Rather they are persistent disinfectants and tend to accumulate over time within the bioreactor. Since the bioreactors employ cultures of naturally occurring beneficial microorganisms, attenuation of these microbial cultures results in reduced process removal of regulated contaminants and possible non-compliance with discharge standards. This problem is generally more prevalent with passenger vessels than with cargo or towing vessels. Passenger vessel operators have legitimate concerns with the spreading disease among the passengers, that may take priority over polluting, so they employ large amounts of complex persistent disinfectants in cleaners and rinses that impacts system health ad operation. 2.The regulations specify that the installation is certified provided it is installed and maintained in accordance with the manufacturers instruction. In the case of biological processes effectively working, manufacturer guidance is to reduce use of disinfectants. But the beneficial culture is being killed or attenuated so that effluent characteristics do not meet regulatory requirements. The offending chemicals in use are complex, large in number and subject to change at any time by the formulators. They are not easily or reliably neutralized as chlorine might be.
The title and scope are in draft form and are under development within this ASTM Committee.