Implementation
- Laboratory scale aerobic wastewater treatment
- Laboratory scale electrochemical wastewater treatment
- Laboratory scale anaerobic digestion
- Mapping of selected waste water treatment facilities
- Off-line vibrational spectroscopy
- On-line vibrational spectroscopy
- Biological wastewater treatment
- Courses and seminars
Laboratory scale aerobic wastewater treatment
Laboratory scale electrochemical wastewater treatment
This subproject highlights possible applications of electrochemical technologies in wastewater treatment. Particular focus will be on a combination of electrocoagulation (EC) and electroflotation (EF).
EC has been used for wastewater treatment, with either aluminum, iron or hybrid Al/Fe electrodes to produce a flocculated sludge. This sludge can be separated from the treated water by using EF, which is a technology effective in removing colloidal particles, oil & grease, as well as organic pollutants. It has been proven to perform better than either dissolved air flotation, sedimentation or impeller flotation (IF).
A small unite in laboratory scale will be constructed and tested at Umeå University in the spring 2013. Samples will be taken manually and pH, temperature and salt content will be varied to find the best conditions. The results will be evaluated during the autumn 2013 and a large scale unite for a small waste-water plant will be suggested.
Laboratory scale anaerobic digestion
The
laboratory scale anaerobic digestions are carried out in two 37
litres continuously stirred reactors located at the
Technobothnia Research Center in Vaasa. The digestions are
carried out as part of another project (BioBio),
which makes it possible to collect samples for measurement purposes
relatively effortlessly. The objective is not to directly enhance
the performance of the digesters, but rather to collect samples and
evaluate the usability of vibrational spectroscopy for quantitative
liquid phase measurements. This will give an insight into how well
the methodology is suited for future process monitoring and
optimisation purposes. The focus is put on the important
constituents volatile fatty acids and ammonium. Among the volatile
fatty acids, acetate and propionate are of primary interest, since
they make up for a large portion of the total volatile fatty acids.
The feasibility of NIR and IR spectroscopy for off-line and at-line
measurements will be evaluated. Additionally the aim is to test IR
spectroscopy combined with in-situ ATR technology for on-line
measurements.
Mapping of selected waste water treatment facilities
Off-line vibrational spectroscopy
The
use of off-line vibrational spectroscopy within the Mare Purum
project serves three purposes. The first is to collect calibration
data for on-line applications in the project. The second is to
conduct pre-studies for future on-line applications within or beyond
the time frame of the project. The third purpose is to evaluate the
performance of the technology as a rapid multi-constituent
measurement technique, for applications within the field of
wastewater treatment, were on-line measurement is deemed redundant
or infeasible. An example of the last category is measurements of
the anaerobic digestion (AD) process with NIR spectroscopy. In this
application an advanced sampling loop with cleaning cycles and
removal of excess particulate matter is probably needed in order to
obtain a reliable on/at-line measurement. On the other hand, using
the technology as an off-line instrument enables determination of
multiple constituents within minutes of sample withdrawal from the
reactor. In relation to the time frame of the actual process (approximately
three weeks in batch mode) an off-line measurement of this type can
still be used for process control purposes.
On-line vibrational spectroscopy
Measuring continuously on a process stream and getting near-immediate results for quick feedback is a much-requested item in industrial applications. Near infrared spectroscopy allows fast measurement of a whole spectrum that can be used for classification and prediction of properties or constituents. Measurement can be carried out inline with fiberoptic probes that are put directly in the process stream or at line where a sample is taken out into a vessel for NIR measurement. The NIR spectrum allows calibration for quite a number of organic constituents and physical properties.
Also near infrared imaging can be used online where industrial samples (pharmaceuticals, vegetables, fruit, meat, cereals, forensic samples etc.) pass a linescanning NIR camera and constituents or other properties are calculated almost immediatley and shown as images.
Online measurements of COD has been performed by PulpEye on the sewage from a pulp industry, SCA Obbola. The instrument used was a RedEye manufactured by PulpEye AB, Örnsköldsvik, SWEDEN.
Biological wastewater treatment
Waste water treatment at Norrmejerier dairy
An anaerobic treatment plant exists at the Norrmejerier diary plant in order to clean the waste water to meet environmental requirements and to produce methane gas. The gas is used internally for heating the factory and other heating purposes and fulfills a great part of the plant's energy demand. The raw materials for the methane fermentation consist of waste water from the dairy production, wastes from stores and some other internal sources etc. Since a large part of the organic material is fat from the factory this process is somewhat different from other comparable anaerobic plants.
The fermentation process is a multistep bacterial process. In the first step, the hydrolysis, fat, proteins and carbohydrates are partly decomposed into monomers which is an enzymatic process where cellulase, protease and lipase are produced by bacteria. This process is dependent on the bacteria population and factors like pH, temp. It is considered as the rate limiting part of the whole methane producing process. In the next reaction, the acidogenesis, amino acids and simple sugars are fermented to organic acids as acetic-,butyric- and propionic acids and some alcohols. The composition of VFA is dependent on pH, temperature and what kind of materials that enters the process.
In the acetogenisis longer fatty acids are broken down to acetic acid, hydrogen gas and carbon dioxide. In the last step methane producing bacteria convert acetic acid and H2 and CO2 to biogas.
Courses and seminars