Newsletter 01.2015

Direct Real-time N2O monitoring

VTUF Case plant: Marselisborg WWTP. In cooperation with DHI and Aarhus Vand. Running from jan-dec 2015. Demonstrating energy efficient treatment plants without deteriorating the climate impact. Special focus on balanced energy savings on aeration systems and optimal carbon splitting for anaerobic digestion and denitrification. On-line CO2- equivalent emission model including N2O.

MUDPCase plant: Randers WWTP. In cooperation with Stjernholm and Randers Spildevand. Running from Q4 2014 to Q1 2016.Combination of real-time oxygen transfer rate (OTR) measurements (including kLa estimation) for more precise N2O emission calculations.

• Introduction• New Projects• Nitrous oxide monitoring...• Where to meet us• Did you know...• New science report

NEW PROJECTS

Introduction Welcome to the first newsletter from Unisense Environment - We will do our best to make them short and informative!

We also encourage you to Follow us on LinkedIn and visit our website from time to time to keep updated on latest N2O knowledge and applications.

Nitrous oxide monitoring puts VCS Denmark at the technological forefrontWastewater treatment has previously been a very energy-intensive process, but in recent years the industry has focused on reducing CO2 emissions. VCS Denmark, one of the largest and oldest water and wastewater companies in Denmark, is actively committed to resource optimisation. One of the major efforts has been on optimising its biggest treatment plant – Ejby Mølle Renseanlæg – so it produces significantly more energy that it consumes.However, in its efforts to achieve its goal, VCS Denmark encountered a problem: When you reduce energy consumption in the complex microbiological treatment

process, you also potentially increase N2O emissions. N2O is a potent, overlooked greenhouse gas which – when emitted – has an eco footprint 300 times that of CO2.

Overview of Ejby Mølle WWTP. Aerial photo from VCS

Installation at Aarhus Vand.

Did you know….During the winter in temperate zones, N2O is often in phase with NH4 and is produced during denitrification - but in the summer with warm temperatures this shifts and now N2O is in phase with NO3 and N2O is procuced during nitrification!

Did you know….Besides the readily available N2O concentration and process temperature data from two N2O sensors, the N2O Wastewater System offers a variety of PLC and SCADA connection interfaces. The system is therefore very easy to connect into your existing sensor infrastructure. As standard the system has 4 scaled 4-20 mA outputs for N2O concentration and emission rates and offers advanced communications/networking via Profibus-DP, MODBUS

RTU, Ethernet/IP and MODBUS TCP. Data can also be logged directly on the N2O Wastewater Controller for later downloading on a USB-stick. To researchers and process engineers we also offer a software solution for browsing the N2O concentration, tank temperature and emission data.

Measurement technology reads N2O concentrationIncreased levels of N2O do not sit well with VCS Denmark’s goal of reducing greenhouse gas emissions and becoming CO2 neutral. The company therefore decided to invest in N2O sensors from Unisense Environment.“We wanted to measure N2O levels in our wastewater treatment tanks, as these data enable us to optimise the operation of our treatment plants and reduce N2O emissions. Unisense Environment had the technology we were looking for – and at a very affordable price,” explains Per Henrik Nielsen, project manager at VCS Denmark.N2O measurement – a giant leap forwardUp until now, N2O concentration and emission data have been scarce and the wastewater treatment companies have therefore based their control efforts on guesswork and lab tests from the 1990s. Armed with the new technology, however, VCS Denmark can now measure N2O concentration levels with a high degree of accuracy.“There’s a big difference between lab tests and the real world so it’s a huge leap forward to be able to perform

stable, full-scale, online N2O measurements in an industrial context online 365 days a year using Unisense Environment’s measurement technology,” says Per Henrik Nielsen.

Deep background knowledge and respect for practice“Unisense Environment possesses extensive theoretical background knowledge and a deep understanding of the biological processes in wastewater treatment. They have also shown a great deal of respect for how things work in practice and understand our operational needs. That’s a rare but highly desirable combination, which we value highly,” he concludes.

Follow this link and read the hole customer case story www.unisense-environment.com/ New science report

Summary from the recent published IVL report“Important sources of climate impact in WWTP are, nitrous oxide from reject water treatment in SBR by nitrification-denitrification, nitrous oxide from activated sludge process.... Measurements are recommended to learn about the emissions from the various sources on the individual plant.” Read report summary in english on page 9 of the pdf. Link to report!

Ejby Mølle WWTP

Data from Marselisborg WWTP, Aarhus

Where to meet usThis coming year we will attend the following events plus events being planned in the UK.

July 16 - Abwassertechnisches Semina in Münich, Germany Sep 26-30 - WEFTEC 2015 in Chicago, USANov 3-6 - Aquatech 2015 in Amsterdam, Netherlands