The cleaning and treatment of fresh water and sewage is associated with hazards just as much as the maintenance of the sewage system itself: The presence of toxic or flammable gases and oxygen deficiencies are potentially risky. If you know the risks, you can control them and provide employees with reliable protection.

The water industry is faced with a range of different confined spaces in which to work: treatment units, tanks, service reservoirs, chemical handling and storage areas, pumping stations, wells, sumps, overflows, boreholes, sewers and manholes. The most frequently occurring hazards are methane, hydrogen sulphide and a lack of oxygen.

The challenge

The water industry bears great responsibility. It has to deal with limited resources and contributes to the health of billions of people. Despite all the technological progress, it is still people – employees of the water and sewage industry – who ensure that everything runs smoothly. This includes inspection patrols, cleaning and maintenance work, repairs and dismantling: despite careful risk analysis, there is always the potential of contact with hazardous substances, which can be dangerous or even fatal to health. Employees who work supporting the ongoing cycle of water recovery, cleaning, supply or discharge pipes, as well as reprocessing and disposal of sewage sludge, must be given special protection to enable them to perform their jobs safely. If the risks cannot be permanently diminished via a safe system of work, a protection concept tailored to the specific activity is required. The concept will focus on the key aspects of gas detection, respiratory protection, personal protection and training.

The risks

There are specific risks to staff and facilities in each stage of the water recovery and treatment process, which in particular include toxic gases, flammable gases and low oxygen levels. Even today, working on water or sewage channels still requires manual visual inspection, fixing faults, maintenance and cleaning. A lack of ventilation combined with biological fermentation processes and chemical reactions encourage the accumulation of methane (CH4) or even hydrogen sulphide (H2S) at critical concentrations. CH4 is extremely flammable and can react explosively. Even at very low concentrations, H2S is extremely toxic to the human body. There is also a range of chemical and biological reactions which can reduce the level of oxygen in breathable air and increase the risk of asphyxiation if workers are inadequately protected. Furthermore, the chlorine used for water disinfection is derived from a highly noxious gas which, even in the smallest quantities, is harmful to the respiratory system.

The solution

Recognising, analysing and assessing risks are important pre-conditions in order to develop solutions for work in confined spaces, handling hazardous substances, plant safety and emergencies. The plant-specific hazard assessment provides a detailed list of risk factors for certain activities and areas of the plant. To find the right solution for every one of these stages of water purification and waste water handling is challenging. Gas measuring devices with fast responding sensors, personal protective equipment such as respiratory protection with adequate filters and protection classes as well as appropriate escape devices are needed. The right devices at the right time, at the right location can protect employees against upcoming hazards. The goal is to achieve a healthy balance between sufficient protection and minimal physical strain on workers to avoid the consequent restrictions on efficiency. It must also feature a portfolio, which can be utilised economically and dependably throughout its life cycle. If you are faced with the challenge of procuring the best material for you and your employees, you can trust Dräger. Our portfolio has an answer to the most diverse requirements of your working practice.