Waste management

The majority of the Company´s waste is produced in the wastewater treatment process and in the Technical Services Department. A total of 45,718 tons of waste was produced in the Company in 2014.

The majority of waste is non-hazardous waste. Mixed municipal waste created an ecological footprint of 374 ha/y in 2014. Compared to the previous year, the amount of mixed municipal waste has slightly dropped.

Waste from wastewater treatment

One of the largest shares of non-hazardous waste is made up by sludge, which is a by-product of a wastewater treatment process. Other treatment processes also produce a significant amount of waste, such as screenings and grit from sand traps. All sludge is recycled and sold to customers or used as planting soil at different construction sites. We give our best to find ways of additional treatment of other waste produced in wastewater treatment and to reduce the amount of waste taken to the landfill.

In 2014, 34,654 tons of sludge were removed in the course of a wastewater treatment process, 32,109 tons of which were transported to Paljassaare composting fields and 2,545 tons to Liikva composting fields.

Amount of sludge, screenings and grit from sand traps directly depends on the amount of incoming wastewater, weather conditions and efficiency of City cleaning services. The amount of sludge and screenings removed from the process in 2014 was larger compared to 2013. Increased amount of screenings is mostly related to the fact that the sand washers and strain presses were replaced with new and more efficient equipment.

Excavation waste

Excavated soil and stones from the networks maintenance and repair works form the bulk of the waste produced. After the amendment to the Tallinn City Excavation Works Regulation in 2010, which set an obligation on the performers of excavation works to carry out asphalt reinstatement works in a larger volume, we have been actively searching for opportunities of planning the excavation works better.

Starting from 2013, we perform most of the network reconstruction works using the so-called no-dig method. No-dig method enables to carry the works out faster and it reduces the inconveniences caused by traffic jams during the road works. Furthermore, the no-dig method reduces the load on environment during network construction, because less soil is excavated and there is no need to store the waste and refill the ground later. At the same time, due to the increase of work volumes and reorganizing of works, the amounts of metal (manhole covers disposed from the reconstruction of tramway in Pärnu Rd), asphalt waste, construction and demolition waste, concrete and brick waste increased in 2014.

Other waste

In 2014, the Company continued to separate paper and cardboards from mixed municipal waste, in order to allow further recycling and reuse of paper and cardboards and save natural resources.

To reduce the amount of paper used, we increased the proportion of electronic bills sent to customers, improved self-service, transferred to the new electronic document management system and made double-sided printing automatic, where possible.

Increase in the amount of biodegradable waste was connected to a new stationary canteen being opened in 2014 at Paljasaare Põik 14.

Amount of hazardous waste is, as a rule, small and mostly related to the old oil and oil waste from the maintenance of machinery and equipment. Figures for 2014 include also the hazardous waste collected in 2013 as the hazardous waste containers were not emptied in 2013.

Reuse of sludge

The main part of recycled waste was wastewater sludge. Raw sludge removed during the technological treatment process is digested for at least 15 days in a digester at the temperature of 37°C. Digested sludge gets dried by a centripress until the dry matter content of 30%. To produce planting soil, the process continues by mixing dewatered sludge with peat at the rate of 2:1. Thereafter the sludge mixture is prepared on Paljassaare and Liikva composting fields by mixing it at least three times per annum, after which the planting

We analyse the mixed sludge against the requirements established in the Regulation No 78 of 30.12.2002, issued by the Minister of Environment, four times per annum. All of the analyse results on the treated sludge and the established maximum allowed values are available on our homepage www.tallinnavesi.ee.

The share of reused waste in the non-hazardous waste is similar to the previous years - approximately 90%, if we take into account the reuse of wastewater sludge and the waste handed over to our partners.

Waste permits

The Company has currently one waste permit issued for Paljassaare and the other permit application in process for Liikva. All terms and conditions of waste permits, valid at that time, were met in 2014.

By the end of 2013, a total of 24,548 tons of sludge mixture from the previous year’s production had remained in stock on Paljassaare composting field. During 2014, 23,834 tons of this amount were sold to the customers and, in the same period, additional 32,109 tons of sludge from the process were deposited onto the field. By the end of 2014, 32,823 tons of sludge mixture had remained in stock on Paljassaare composting field, out of which 7,079 tons is not, according to the new waste permit L.JÄ/325362, being recycled.

During 2014, a total of 8,069 tons of soil from Liikva composting field was sold to the customers and additional 2,545 tons of sludge from the process were transported to the field during the reporting period. By the end of 2014, the stock in warehouse was 0 tons of sludge mixture, i.e. everything had been handed over to the customers.