Wastewater treatment and sludge management in Klaipeda region Chief wastewater treatment engineer Vaidotas Girdvainis

Klaipeda city First mentioned in the Chronicles of Memelburg in 1252, Klaipeda is the oldest city in Lithuania.

Klaipėda historically also known as Memel, is a city in Lithuania on the Baltic Sea coast. It is the third largest city in Lithuania and the capital of Klaipėda County. The population - 157,350

Popular seaside resorts close to Klaipeda are Nida to the south on the Curonian Spit, and Palanga to the north.

AB „Klaipėdos vanduo“ Established in 1902 Authorized capital– 56,06 mln. euros The number of employees – 392 Number of water service plants - 62 Number of wastewater treatment plants - 15 Number of sewage pumps stations – 86 Supply drinking water for 90,952 customers

Key figures of 2015 Supplied water to networks – 11,25 mln. m 3 Sold water – 9,6 mln. m 3 Treated wastewater– 15,54 mln. m 3 Sold services of wastewater treating– 8,7 mln. m 3 Turnover – 14,7 mln. euro Net profit – 0,11 mln. euro

Water supply system 62 water service plants: - 4 in Klaipeda city - 58 in Klaipeda county 81 water boreholes 34 third level pumping stations 690,7 km of operating water supply network

Water supply in Klaipeda

Wastewater treatment system 676,3 km of operating wastewater networks 86 sewage pumping stations: - 49 in Klaipėda - 37 in Klaipėda district 1 wastewater treatment plant of Klaipeda. 14 small wastewater treatment plants in Klaipeda county. Annually cleaning about 570 thousand m3 of wastewater (~ 48 thousand m3/month). Wastewater treatment plants located far from each other. Total distance between all the small waste treatment plants is about 300 km. For maintenance and proper operation of wastewater treatment plants are responsible District wastewater treatment service (6 employees).

Wastewater treatment plants location in Klaipeda county Klaipėda WWTP

Wastewater treatment processes supervision, control and data system (SCADA)

Basic facts about the Klaipeda WWTP 1998 start up into service of biological wastewater treatment plant; The designed biological wastewater treatment plant capacity after reconstruction of the active sludge reactor, nitrogen and phosphorus removal technology in 2003, is up to 29,2 million m3 per year; In 2008 was installed chemical phosphorus treatment; In 2009 was built sludge digestion plant (investment 12,16 mln. euro); In 2013 was built a sludge drying facility (investment 6,66 mln. euro); Wastewater treatment effect up to 98%; In 2015 treated 14,97 million m3 of wastewater; Wastewater treatment plant employs 25 people staff.

Klaipeda wastewater treatment plant process description The primary mechanical wastewater treatment; Biological wastewater treatment is combined with chemical phosphorus treatment; Sludge digestion; Sludge dewatering; Sludge drying; Energy plant – biogas is used as a source of energy.

Wastewater treatment requirements and operation results in 2015 ParameterInlet, mg/lOutlet, mg/l Effluent permit limit values, mg/l Designed effluent, mg/l SS487,92,35- 15,0 BOD 7 420,993,9915,0 20,0 TN81,299,7210,0 15,0 TP9,430,281,01,5

Wastewater treatment overview in

Sludge management and energy plant

Energy plant The produced biogas is using for energy in the central combined heat and power plant. The power plant is equipped with 3 biogas generators (each generator electric power 311 kW el ). A biogas powered engine energy converting into electricity and thermal energy. Electrical energy is used for own needs. Currently generators producing for almost 70% of the wastewater treatment plant required electric power. Thermal energy is used for digesters and biological biogas cleaning. Sludge drying using spare heat from this 3 generator, and from installed an additional 600 kW el power generator, which is using landfill or natural gas. Total produced amount of biogas 2015 m. – 2,02 mln. m 3 /a (5 524 m 3 /d) The total produced amount of electricity 2015 m. – 3288,33 MWh/a (9009,12 kWh/d) Total produced amount of heat (designed) – 6456 MWh/a

Sludge drying In 2013 was built a sludge drying plant, which is available to dry up to 18,000 t/a of dewatered sludge. This low- temperature belt dryer (manufacturer Sülzle Klein GmbH) with a capacity of 4,800 t/a of dried sludge (90 % SM). Also within this project was installed the Austrian company‘s VTA Technologie GmbH ultrasonic excess sludge disintegrating facility, which allows to increase the amount of generated biogas in digesters up to %.

Change of biogas production amount after installation of ultrasonic sludge disintegration unit

Sludge drying plant

Sludge drying The dewatered sludge from centrifuges (also sludge from other treatment plants) comes to 400 m3 volume bunker. From bunker sludge are pumping to distributors. The distributor evenly spreading sludge on top of the dryer belt. In the dryer sludge is transporting through a drying zone at 80-90°C where the heated air removes moisture; Dried sludge are crushing and transporting in to the silo (150m3), where are storing until unloading; During drying process, outgoing air is cleaning in scrubber, afterward in biofilter and discharging into the environment.

Sludge drying facility

The sludge volume reduction Liquid sludge 1000 kg; 4% SM Mechanically dewatered sludge 144 kg; 25% SM Dried sludge 44 kg; >90% SM

Sludge drying benefits A significant volume of sludge reduction of an average of 4 times compared with only dewatered sludge; Dried sludge is stable consistency, easy to transport; Dried sludge is odorless; Dried sludge storage is simple, does not require large investments; Dried sludge could be used as a biofuel, the energy value MJ/kg; Extensive usability: agriculture, burning, mineralization, etc.

Sludge management options in Lithuania Direction - utilize sludge from wastewater treatment plants as waste. Currently, potential utilization methods in Lithuania: Sludge utilization in waste incineration plant. For example in JSC „Fortum Klaipeda“. Disposal cost Eur/t. Sludge utilization in cement plants, sludge burning as fuel. For example in Akmenės cement plant. Disposal cost 13,00 Eur/t. plus transporting Sludge as fertilizer for energy forests. A proposal from JSC „Galzdonų plantacija“. Disposal cost 40 Eur/t. Design and construct sludge incineration plant near to the sludge dryer, the resulting heat use for sludge drying. For example project in „Utenos vandenys“. Dispose sludge in composting sites. At the moment dried sludge is composting in Dumpiai composting site. Disposal cost 17,10 Eur/t.

Waste water treatment and sludge handling challenges Reducing wastewater pollution at source. Regular environmental education. To reduce the heavy metals into wastewater collection systems, which would allow extending sludge utilization. Total nitrogen treatment improvement. Minimize electricity consumption in wastewater treatment and sludge handling, preventing the infiltration into the sewerage networks. Sludge drying cost reduction, raising the extracted biogas production, using alternative fuel sources. Minimize formation of struvite salts in the sludge pipes. Dried sludge disposal, the final arrangement.

Questions?