Case Study: Modernization of the clarifiers (Awgustow, Poland)

PROJECT – Modernization of the secondary clarifier
CUSTOMER – Wodociągi i Kanalizacje Miejskie Sp. z o. o. w Augustowie
OBJECT – Wastewater Treatment Plant in Augustów
COMMISSIONING – October, 2018


Wastewater Treatment Plant is located in the South part of the Augustów city. It is a mechanical-biological type of plant adapted for deep removal of the biogenic compounds. Water needs to pass several steps and once purifi ed, it is drained to the Netta river. The maximum capacity of the plant is 10 000 m3/day. In June 2018 PRODEKO-EŁK Sp.zo.o. (Esmil Industrial Group) has been chosen as a main devices and technology supplier to accomplish the task of secondary clarifi er modernization at the Wastewater Treatment Plant in Augustów.

Modernization purpose

The main goal of the modernization was to:

  • ensure the stable work of the secondary clarifier
  • increase the removal effi ciency of the fl oating parts and the sludge
  • decrease the operating costs

Initial stage

As part of the signed contract a radial sludge scraper ZGRwt-25 type and the penstock SGSM type have been supplied. The scope of work carried out included preparation of the documentation to fabricate the devices and necessary parts properly adapted to the dimensions of the clarifi er and the sewage disposal channel, as well as assembly and technological commissioning of the supplied devices.

Results and conclusions

The use of modern technological solutions in the design of devices ensures high work efficiency, energy efficiency and reliability. As a result of replacement of the existing sludge scraper at the Wastewater Treatment Plant in Augustów the following were achieved:

  • increase in the efficiency of floating parts and sludge removal due to the special design of the scraper elements;
  • high level of energy efficiency of the device due to the use of energy saving trolley drive with the gearbox embedded directly within the wheel;
  • lowered operating costs of the device related to maintenance and repair.

Case Study: Modernization of the Primary and Secondary Clarifiers (Slupsk, Poland)

PROJECT Modernization of the primary and secondary clarifi ers
CUSTOMER Wodociągi Słupsk Sp. z o.o.
OBJECT WWTP Slupsk, Poland


The wastewater treatment plant is located in the northern part of the Słupsk city, on the right bank of the Słupia River. It is a mechanical-biological treatment plant, adapted for deep removal of biogenic compounds in a threephase, modified Bardenpho process, supplemented with a predenitrification chamber. The capability of the treatment plant corresponds to 200,000 population equivalent, and the average daily fl ow of about 19 647 m3/day.

In November, Esmil Prodeko-Ełk Sp. z o.o. has been selected as a General Contractor and signed an agreement with Słupsk Waterworks for the task: “Delivery of a dewatering centrifuge and scrapers to the municipal sewage treatment plant in Słupsk at ul. Sportowa 73 – task no. 2 – Delivery of the scrapers along with the performance of necessary construction, assembly and installation works.

As part of the contract, the following facilities were modernized:

  • Preliminary settling tanks with a diameter of D = 34m – 2 sets
  • Secondary clarifiers with a diameter of D = 40m – 2 sets

The modernization included dismantling of the old scrapers, delivery, assembly and kick-start of the new ones and also commissioning and warranty tests.

Initial Stage

The preliminary settling tanks were built in the first stage of construction of the wastewater treatment plant in 1986 and equipped with radial scrapers according to the solutions used in the 1970s. As a result of the modernization of the sewage treatment plant in 2006-2009, one of the primary settling tanks has been adapted to the retention and overflow function. The technical condition of the scrapers at the initial stage of the project was very poor and qualified them for replacement. In case of secondary clarifiers,
the situation was similar, with the diff erence that the facilities were built in 1978 and modernized in 2001.

Project Goals

The main goal of the signed modernization project was to improve the efficiency of sludge removal from both primary and secondary clarifiers.

In order to solve the problems and ensure stable and proper conducting of the technological process in both the sewage and sludge part, it was necessary to replace the scrapers in two primary settling tanks with models ensuring greater efficiency and reliability. Ultimately, this meant to improve the balance of the initial and excessive sludge, and thus increase the biogas production and reduce the operating costs of the treatment plant. Also the scrapers had to be replaced on the two existing secondary clarifiers. Part of the modernization was to supply the equipment with so-called side scraper, similar to ones mounted on two clarifiers that were built in 2008-2009.

Project Implementation

The modernization project of the preliminary and secondary clarifiers has been carried out between 15th of October 2018 and 28th of March 2019 and consisted of:

  • disassembly of the old (existing) scrapers and placing them in the containers provided by the INVESTOR,
  • preparation and delivery of the new scrapers made entirely from AISI 304 (1.4301) steel, sized to existing facilities,
  • installation of the new scrapers in an alternating system, i.e. first preliminary, then secondary, then again preliminary and finally secondary clarifier
  • technological start-up of each of the settlers and putting them into operation.

Results and Conclusions

As a result of modernization of the preliminary settling tanks, by installing new scrapers, problems related to ensuring stable and correct conducting of the technological process in both the sewage and sludge part were solved. The new scrapers are characterized by greater efficiency and operational reliability, which significantly contributed to the improvement of the initial and excessive sludge balance, and thus to increased biogas production and reduction of the operating costs of the treatment plant.

However, as a result of replacing scrapers in the existing secondary clarifiers with the devices equipped with so-called side-scraper, the removal of activated sludge excess to the surface of the settling tank in relation to normal operating parameters has been eliminated. This, in turn, resulted in a decrease of the total suspended solids discharged with sewage,and with it the load of carbon, nitrogen and phosphorus in the treated sewage to the Słupia river.

By replacing scrapers with ones equipped with the catching scrapers, the duration of active sludge retention within the secondary clarifiers has been shortened, which has prevented the formation of anaerobic conditions and secondary biological dephosphorization, and as a consequence – the process of secondary release of the orthophosphates into the wastewater from the activated sludge accumulated at the bottom.

Case Study: Modernization of Sewage Treatment Plant (Myszkow, Poland)

PROJECT Modernization of the secondary clarifier
CUSTOMER Schumacher Packaging Zakład Grudziądz Sp. z o.o.
OBJECT Local WWTP, The Paper Factory in Myszków


The Paper Factory in Myszków was founded in early 1894 year, where at the time it was the largest paper production plant in Poland. In 2016, the factory became part of the Schumacher Packaging group. To ensure high quality standards and increased paper production plant modernization project has began. One of the main tasks of the project was to increase the throughput of the existing sewage treatment plant located on the production plant premises. In July 2018, PRODEKO-EŁK Sp.zo.o. (Esmil Industrial Group) was chosen as the main contractor for the modernization of the secondary clarifi er at the Sewage Treatment Plant of the paper factory in Myszków.

Modernization Purpose

The aim of the project was to replace the existing radial sludge scraper and the drainage system of the secondary clarifier with a diameter of 39.4 m. The mounted device is designed to ensure high effi ciency of sludge and floating parts removal.

Initial Stage

The modernized secondary clarifi er was not exploited for many years. It was equipped with a radial sludge scraper made from black steel and also concrete drainage troughs. The plan was to remove the scraper with troughs, repair of concrete elements of the clarifier, assembly of a scraper along with the trough system made from stainless steel.

Project Implementation

As part of the contract, a ZGRwt-39.4 type of a radial scraper has been delivered with a drainage trough system. The scope of work included preparation of the documentation to fabricate the parts adapted to the size of the settling tank as well as assembly and technological commissioning of the supplied devices.

Results and Conclusions

The use of modern technological solutions in the sludge scraper designing ensured high work efficiency, energy efficiency and reliability. As a result of the installation of the new scraper hasthe following goals have been achieved:

  • ensuring effective removal of the sludge and floating parts;
  • reduction of electricity consumption;
  • ensuring stable and trouble-free operation.

Reference of Wabra Contractor, Zahran, Kingdom of Saudi Arabia

By here with we WABRA CONTRACTOR EST note that during the cooperation with the company Esmil it has acquired a reputation as the organization of highly professional specialists, which knows subtleties of the operation of wastewater treatment facilities and develops technologies of the highest world level. We, as main contractor, are glad to work with products that are manufactured at this enterprise.

In July 2016, 2 ZSP sludge scrapers with the diameter of 10+8 m were delivered, installed and put into operation in wastewater treatment plant 1500 m3/day for Air Forces Defense in Zahran, Kingdom of Saudi Arabia.

All installed equipment has been operating stably and smoothly from 2016. One of the main advantages of this type of equipment is the serviceability and reliability, Sludge scrapers are structurally designed for a long-term trouble-free operation. No wear of moving parts are observed.

The suggested design is proved to be stable, rigid and reliable in operation. Bridge on the sludge scrapers has central drive and mounted on two independent supports that are placed out of the clarifiers. Such construction allows not carrying and weight on GLS tank where scrapers must operate.

The cleaners of walls and edges of sludge scrapers are well designed, convenient in adjustment and don’t cause dissatisfaction. All the electric part of the drive runs smoothly in various temperature conditions.

WABRA CONTRACTOR EST thanks the team of Esmil for the high quality equipment and careful attention to the needs and requirements of our enterprise during the production, delivery and adjustment of sludge scrapers.

Esmil Group

Esmil Group stands as a premier global manufacturer, crafting cutting-edge equipment for wastewater treatment and sludge dewatering. Additionally, we specialize in delivering advanced membrane systems tailored to various industries.

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Equipment for Wastewater Treatment & Sludge Dewatering.

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