Victor Marine Ltd have recently developed a new Sewage Treatment Plant for the marine market which complies with the latest regulations IMO Resolution MEPC 159(55). The full system has now been B.V. (Bureau Veritas) type tested and is in full production at Victor Marine’s UK premises.
Technological Description
The STP system is designed into three stages, The BioReactor, the Settlement Tank and the Chlorination Tank.
As with many of the systems in the market place, the first stage of the unit is a Biological unit. It is designed on the principles of a Fixed Bed BioReactor (FBBR). There are two main types of bioreactors utilized in biological wastewater treatment – activated sludge processes and fixed bed bioreactors. Whilst with traditional activated sludge treatment the micro-organisms are suspended in the liquid, they are fixed on a stationary support or surface in fixed bed bioreactor. The most common form and earliest type of fixed-bed bioreactors are the so-called trickling filters (commonly used in land-based sewage systems) that are well proven and have been utilized since the last century.
We have in our FBBR system improved the design to the trickling filters by developing a better stationary support (specially designed filter can increase BOD loading by 50%, vertical flow media structure has optimal structure to expel excess sludge, crossflow structure to ensure no by-pass and complete treatment), better aeration (uniformly distributed aeration tubes and optimised bubble size), flow control (airlift flow control unit to maintain levels and deal with shocks and high loads) and increased surface areas (specially designed honeycomb matrix) to maximise reaction times and biological concentrations. Thus, our process is more efficient than standard FBBR in the market place and also compared to the activated sludge process, it has a smaller reactor size, higher removal efficiency, reduced odour annoyance and robustness towards hydrodynamic variations and shocks in the inlet concentration.
The system does not require additional pumping (only inlet and outlet) and all transfers are done by gravity or airlift, no additional energy is required so the energy consumption can be extremely low.
The Settlement tank is designed with tube settlers inside that can multiply the sedimentation area. This reduces again the space required and produces a better and more consistent effluent.
The final stage is the Chlorination unit and in our system we use a tablet dispensing system. The treated water is fed into the chlorinator, added with chlorine and sent to the chlorine contact tank. The tablet system is simple and easy to both use and manage, saving the engineer’s time when operating. Once the treatment is complete, the fluid is pumped out/overboard through the de-chlorination unit to remove any excess chlorine (as per IMO requirements).
For information, Victor Marine manufactures these STP units in 15, 30 or 50 man units with Optional items available. Should you require any further information, please do not hesitate to contact us.
