Handling of chemicals

We use approximately 450 hazardous and less hazardous chemicals in its operating activities. With regard to the health and wellbeing of our employees we deem a safe handling of chemicals at the work site extremely important.

The amounts of chemicals used at the treatment plants predominantly depend on the weather and quality of water to be treated. In 2014, we used a total of approximately 6,400 tons of different chemicals. In 2013, this figure was approximately 6,300 tons.

By applying and following the required safety rules we have minimized the likelihood of accidents involving highly poisonous chemicals.

Water treatment chemicals

Chlorine

Ülemiste Water Treatment Plant treats surface water into drinking water and the process uses chlorine as a disinfecting chemical. The most common disinfectant in use is chlorine, which is effective and has a long-term effect in the water distribution network. Chlorine has a strong oxydising effect and is extremely poisonous for aquatic life. We have been classified as a category B Company with risk of a major accident in Estonia due to the large amounts of chlorine stored at the plant and used in the water treatment process.

By applying the necessary safety measures we have minimized the likelihood of chlorine accidents. In 2014, we continued with preventative measures, carried out the necessary trainings for our staff and continued cooperation with the rescue services. In March 2014, we participated in a joint training CBRN Integrated Response 2014, which also included training of a major accident in the chlorine storage in the Water Treatment Plant.

Ozone

Due to the replacement of water prechlorination by ozonation in order to prepare the water for the next treatment stage the usage of chlorine has considerably decreased over the past decades. Ozone is a good and quick oxydiser and effectively breaks down organic matter in raw water. Ozone is produced locally by us and only in amounts needed. Thanks to the closed process and no stock being kept, the environmental risk is minimum.

Coagulants and polymers

Significant amounts of coagulants and polymers in liquid form are added in the treatment process to remove the particular matter (e.g. suspended solids and organic substance) from water.

Usage of water treatment chemicals

Water quality in Lake Ülemiste is strongly dependent on the weather, however, long-term observation has established periodic changes in quality by comparing the years. In 2014, raw water responded well to treatment, irrespective of a hot and sunny summer the level of plankton in the lake was low and the colour as well as permanganic acid indicators were below the average. Historically, the same situation occurred in 2003/2004. Consequently, the treatment process was optimized and smaller doses of chemicals were used.

Wastewater treatment chemicals

Methanol

We use methanol at Paljassaare Wastewater Treatment Plant to increase the nitrogen removal efficiency of the bacteria participating in the biological treatment process. Due to the methanol used in the wastewater treatment, we have been classified as one of the most hazardous companies in Estonia on the basis of the legislation related to chemicals.

Coagulants and polymers

Significant amounts of coagulants and polymers are used in the wastewater treatment process. Coagulants are used for the chemical processing of wastewater to remove phosphorus. Polymers are used to change the qualities of sludge by accelerating the dewatering process.

Applying and following the required safety rules makes the use of highly poisonous chemicals fully safe for both the people and environment.

Usage of wastewater treatment chemicals

The amount of chemicals used in the wastewater treatment process is dependent on the pollution levels of incoming wastewater being in its turn affected by the weather. The higher the concentration of pollutants in incoming wastewater and the lower the limits of pollutants in the treated effluent have been set by the legal requirements, the higher is the volume of chemicals used in the wastewater treatment process. The use of chemicals in 2014 roughly stayed in the same range with 2013. The use of coagulant was higher by approximately 300 tons and this relates to higher load of phosphorus in the incoming wastewater. Also the amount of polymers used was higher than in last few years.

Ensuring the safety of chemicals

By applying the security and safety rules of handling of chemicals we have minimized the likelihood of accidents involving highly poisonous chemicals.

The necessary conditions for the storage and use of all chemicals have been created, also the information on the chemicals safety data sheets, the legal requirements and the safety instructions are followed. Absorbents and personal protective equipment are also available at all chemicals’ handling sites. The sites for handling hazardous chemicals are equipped with automated alarm and degassing system for the early detection and liquidation of possible leakages. Chemicals’ safety data sheets are available on hard copy, but also electronically in our Document Management System.

We have established procedures and crisis plans for ensuring the training of employees and the liquidation of emergencies. Provided that the right security and safety requirements are followed, the likelihood of emergencies with chemicals (chlorine, methanol, biogas) with serious consequences to human health and the environment is very low. During the trainings organized each year we repeat all technologies used in the water and wastewater treatment plants, potential risks, locations and usage standards of chemicals.

A follow-up training for the staff on chemicals’ safety was held in the Wastewater Treatment Plant in 2014. The training organized in the Water Treatment Plant was mostly aimed at the safe handling of chlorine and prevention of operating mistakes. The training also included presentation by a Rescue Department’s representative. The alarm systems were checked and tested, also the sound systems were tuned and tested.

In 2014, no reported accidents with chemicals occurred, which could have caused damage to people or the environment.