Helsinki Region Environmental Services Authority

HSY

• An end user’s point of view• Today’s – and tomorrow’s – challenges in wastewater

treatment– Linked to MMEA research and development projects by

e.g. Valmet, VTT and the Universities of Oulu and of Eastern Finland using Viikinmäki WWTP as measuring platform

”Why do we need new and improved on-line monitoring and data analyses in wastewater treatment?”

”Why do we need new and improved on-line monitoring and data analyses in wastewater treatment?”

Process Challenges

•Requirements‒Good effluent

quality (constantly)‒Sludge quality

Challenges

•Limitations‒Space, energy,

chemicals, work

•External conditions‒Fluctuating loading‒Temperature changes

03.05.2023 6

Fluctuating Loading ConditionsOrganic load (kg BOD/d)Flow (m3/d)

Temperature (oC)

Solids (mg/l)on-line value

•Stricter requirements‒N, P, COD…

•New requirements‒Chemicals, drugs,

metals, pathogens…

Challenges …tomorrow

•More efficient use of resources

•Increasingly challenging conditions‒Growing influent loads‒More extreme rain events

‒Energy‒Chemicals‒Footprint

•Higher level of automation

‒Control of flows, chemical feeds and biological process

•Higher knowledge‒Better tools for

operators

Tools

•Reliable measurements in challenging conditions

‒E.g. solids measurements in sludge treatment

•Intelligent use of data‒Correlations, predictions…‒Clear outputs

Influent Quality

Challenges• Large variations in influent concentrations

– Largely correlated to solids content • Laboratory anayses are time consuming and costly

– Not done daily, even less hourly• Problematic environment for on-line measurements

– Solid wastes, grease and sand• Measurement values could be used for:

– Raw sludge pumping (thickening, constant load to digestion)

– Treating by-pass waters (chemical dosages, treatment result)

Reliable on-line measurement of influent solids

03.05.2023 11

Activated sludge

03.05.2023 12

Activated Sludge

Challenges• Good flocs in activated sludge

– Settling good treatment result & hydraulic capacity– Thickening high retention time and gas production in

digestion• Microscopic examination of flocs

– Time consuming– Requires praxis– Subjective – The registered values are vague

On-line optical monitoring of floc morphology Processing of data to information

03.05.2023 14

Sludge Drying

• The ”success” of sludge drying has a large impact on operation costs– Amount of dried sludge (10 tons 30 % TS vs. 20 tons 15 % TS) – Internal load from reject water solids– Feasibility of treating reject water for total nitrogen

• Polymer use– Crucial, expensive Must be optimised

NOTE: This applies to biowaste digestion plants as well !

Challenges

Reliable on-line solids measurements of thickened sludge and reject water

Using Measurement Results for Optimal Process Control

Challenges• Vast amount of measurements

– With very different levels of importance• Varying time scales• Interpretation of results, values can be important:

– As such – In relation to other values– The magnitude and the direction of change

• Optimal operation in changing conditions ?

Intelligent data processing and useful (= simple) outputs

Thank You!

Helsingin seudun ympäristöpalvelut -kuntayhtymäSamkommunen Helsingforsregionens miljötjänsterHelsinki Region Environmental Services Authority

Puhtaasti parempaa arkea | En rent bättre vardag | Purely better, every day