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Implementation process of PURE investment in Jurmala

After receiving the first draft audit report, Jurmala Water discussed it with investment coordinator John Nurminen Foundation and the project consultant. In these discussions, the following investments were agreed to be realized at Sloka WWTP within PURE project:

  • to purchase and install new measurement and control instrumentation
  • to divide the anaerobic and aerobic zone to internal zones and to lower the walls between the anaerobic and aerobic zones
  • to purchase and install a new polymer unit to improve sludge treatment (separate chemical dosing to the thickening and dewatering equipment).

These investments help the Sloka treatment plant operators to optimize the nitrogen and phosphorus removal performance and to achieve more constant treatment results, to prevent problems with bulking sludge and sludge washouts and to achieve better energy efficiency.

Installations of new walls in anaerobic and aerobic zones. Photo: John Nurminen Foundation.
Installations of new walls in anaerobic and aerobic zones. Photo: John Nurminen Foundation.

The procurement process

The tender included both equipment and their installation works; it was launched 27.07.2011 and published in the newspaper “Latvijas avīze” and Jurmala water homepage (www.jurmalasudens.lv). Despite some enquiries from different companies concerning the tender, at first no offers were received.. The tender had to be extended and after that one offer (from a Latvian firm Auctus Consulting) corresponding to the requirements, was received and accepted. The contract between Jurmala Water and Auctus Consulting was concluded 12.01.2012. The price of the delivery and installation contract was LVL 212 000. The necessity to purchase the software to produce sufficient treatment data resulted in contract amendment and after signing it, the total contract amount was LVL 219 500 (without VAT).

The following measurement equipment were delivered and installed with the cabling to the central control room by May 2012:

  • Meters for redox potential measurements (tot. 6 pieces)
  • Oxygen meters (tot. 2 pcs)
  • Ammonium nitrogen meters (2 pcs)
  • Phosphate phosphorus meter supplied (1 pc)

The measurements with the installed equipment were started after the installations and the data collected with the help of specialized dynamic simulation software (BioWin 3.1.) that allows easy management of the data and controlling of the process. SinceAs the investment in Jurmala was delayed, no wintertime data collection could be done as the installations of the measurement equipment could be done only in April.

Measurement equipment and controllers. Photo: John Nurminen Foundation.
Measurement equipment and controllers. Photo: John Nurminen Foundation.


The measurements with the installed equipment were started after the installations and the data collected with the help of specialized dynamic simulation software (BioWin 3.1.) that allows easy management of the data and controlling of the process. Since the investment in Jurmala was delayed, no wintertime data collection could be done as the installations of the measurement equipment could be done only in April.

The air flow meters (2 pcs) and a pressure sensor were supplied on 1st August.2012 and installed in November. The polymer unit (SL1500) was supplied and installed in August - September. Lowering of the walls took place in October. The whole project, including the installation of new walls in anaerobic and aerobic zones, was ready on December 2012. The same subcontractor installed the polymer unit, the new walls and the air flow meters as well delivered the control valves (4 pcs). Tests with the new polymer unit were conducted in December. Installation of the walls required close co-operation between the contractor and Jurmala Water as the water level needed to be lowered (in both basins in a row) and basin emptying is not a regular thing taking place at the waste water treatment plant.

The dynamic simulation software BioWin for wastewater treatment process and BW Controller software for online process management were purchased on 30.11.2012 and installed in December 2012. Total price paid for the software (both components) was LVL 7500.

Polymer unit. Photo: John Nurminen Foundation.
Polymer unit. Photo: John Nurminen Foundation.

Future plans

In the future, Jurmala water is planning to address the still existing problem with nitrification at low temperatures at Sloka treatment plant by improving the isolation of the basin walls. A pilot plant for dosing a chemical to combat seasonal problems with slowly degrading ammonium and organic compounds as well as H2S load has been planned. Also a physical-chemical unit to pre-treat H2S rich waters is a possibility to improve the results of the treatment.

Project of upgrading water conditioning plants is going on but network extension (water and wastewater) is still on Tender evaluation phase.

It has been agreed, that the results of the PURE project investment will be monitored 5 following years of the project by submitting a quarterly report on nutrient removal performance of Sloka WWTP to the investment coordinator John Nurminen Foundation (http://www.puhdasitameri.fi/en).