Effective and sustainable environmental monitoring is a fundamental component of any environmental protection application and is significantly determined by the quality of the available data and measurement parameters. The systematic recording of environmentally relevant substances in turn depends on the quality of the analysis systems used. Sensors used directly (online) in aquatic systems offer the greatest potential for continuous, spatially and temporally high-resolution detection of pollutants. At present, however, sensors for the detection of climate-relevant greenhouse gases such as methane or CO2 have their limitations with regard to the detection limit and water depth. The reason for this is their sample inlet systems (SIS), or more precisely the membrane holders, which are related to most measurement systems. 

These shall be designed to (a) have high permeability/porosity (minimum detection limit of gases to be analysed) and (b) be pressure stable to withstand hydrostatic pressure (max. water depth). The SIS produced today currently meet only one of these requirements at a time, and these are often unsatisfactory.

Within the framework of the project, these two requirements will be optimised so that the detection limit of the sensors can be reduced and the operational capability is still guaranteed even at great operating depths. In order to achieve this, the support of the SIS will be developed with the approach of a bionic structure optimization of the Department of Bionic Lightweight Construction of the Alfred Wegener Institute and additive manufacturing processes with regard to a pressure-resistant structure.

The SIS structure is integrated and adapted to a sophisticated sensor (underwater mass spectrometer) of the Department of Marine Geochemistry of the Alfred Wegener Institute. Thus this development can be used for the industry after the transfer into the market readiness. In addition, the innovation makes a detailed research contribution to the analysis of the effects of methane and CO2 emitted from aquatic systems in relation to climate change. The technology transfer is ensured by a cooperation with the AWI spin-off SubSeaSpec.

The aim of the project is therefore the development of a modular sample inlet system, which for the first time simultaneously meets the desired gas permeability requirements and also increases the range of application by increasing the compressive strength.

The goals include the following points:

• SIS unit adaptable to various sensors
• Improvement of the detection limit of the sensors 
• Higher permeability of the surface than all currently available membrane holders (porosity above 80 %)
• Pressure-resistant, deep-sea structure (operating depth from 2000 m to 4000 m)

Effects and fields of application of the innovation:

•  High-resolution detection of gases such as CO2 and methane, released from the seabed and sediments in wetlands. (Decisive contribution to the analysis of climate change, only achievable by sensors with a corresponding sensitivity)
• Significantly faster detection of very low concentrations of oil and its degradation products in the event of ship or oil/gas platform disasters (initiation of suitable countermeasures without loss of time)
• Continuous environmental monitoring of aquatic ecosystems (the uptake of pollutants leads directly to a disturbance of the ecological balance)

Funding by Senator of Civil Engineering and
BIS - Bremerhavener Gesellschaft für Investitionsförderung und Stadtentwicklung mbH