The wastewater treatment facilities in Trzcianka were built in the 1980s and had a capacity of 2,400 m³/day. The wastewater treatment used the active sludge method, in which the sludge was sent to stabilization chambers and then to sludge clarifiers. The treated wastewater was discharged through a drainage ditch to the Trzcinica River. In 2006-2007, wastewater treatment facilities were modernized and expanded to include both the biological and sludge treatment stages. As a result of these measures, the capacity of wastewater treatment facilities increased to 4000 m³/day. The volume of wastewater received during the year is currently approximately 700,000 m³.
In 2022 Municipal Construction Department in Trzcianka invested significantly in the modernization of both the water supply and sewerage systems and the wastewater treatment facilities themselves. One of them was the modernization of the sludge treatment stage.
The sludge treatment technology at the Trzcianka wastewater treatment facility includes anaerobic stabilization of excess sludge in two separate fermentation chambers (WKF), followed by dewatering and hygienization with lime for agricultural use. Before the modernization, sludge from the WKF chambers with a dry matter content of 1.5-2.5% was sent to the belt filter press, and as a result of dewatering, it was possible to achieve approximately 16% DM in the dewatered sludge.
Due to rising energy prices, the frequency of equipment breakdowns and the high cost of transporting dewatered sludge, the company’s management decided to replace the equipment in the sludge dewatering building with more efficient and cost-effective equipment that provides an automated dewatering process. In search of an optimal solution, the Municipal Construction Department of Trzcianka ordered pilot tests in real conditions on a full-size Esmil MDQ-201 Multi-Disc Screw Dehydrator from PRODEKO-EŁK Sp. z o. o., which is part of the Esmil Group. The tests were positive and promising, and the dewatering technology based on Esmil MDQ Dehydrators convinced the management. In July 2022, a tender was held for the supply, installation and start-up of the Sludge Dewatering Complex based on a Screw Press, which was won by PRODEKO-EŁK, meeting all the Customer’s requirements.
As part of the modernization, PRODEKO-EŁK Sp. z o. o., a part of the international ESMIL group, supplied, installed and started up the Sludge Dewatering Complex in the autumn of 2022, which included the following equipment:
- Mutli-Disc Screw Press Esmil MDQ-452 C
- Horizontal Screw Conveyor approximately 2 m long
- Inclined Screw Conveyor with a length of approx. 6 m, which partially extends outside the building
- Pump for sludge feeding + flow meter
- Polymer inlet pump + flow meter
- Polymer make-down unit
- Macerator pump
- Control cabinet of the entire complex with a touch panel
Esmil PRODEKO-EŁK also carried out a comprehensive supply of pipelines and cables for the complex, as well as mechanical and electrical installation of the devices.
After the complex start-up and adjusting the equipment’s operating parameters, the treatment facility operators rated all the advantages of process automation and technology that requires virtually no operator intervention, especially compared to the previously used belt filter press. In addition, the absence of wearing parts, lower operating costs (electricity, washing water, etc.) and a much higher degree of dewatering result in significant savings. It is worth noting that despite the higher amount of sludge processed per day, the total polymer consumption per month is lower. A detailed comparison of the operating parameters of both equipment is presented in Table 1.
Table 1: Comparison of the previous belt filter press and the Multi-Disc Screw Dehydrator Esmil MDQ-452 C
The advantages of using the Sludge Dewatering Complex based on Esmil Multi-Disc Screw Press MDQ:
- better sludge dewatering, due to the reduced volume of sludge, which means less storage space is required and transportation costs are reduced;
- more dewatered sludge per day;
- less use of polymer, washing water and electricity;
- no parts that wear out quickly;
- does not require maintenance;
- automated process.