scholarly journals Methods of monitoring of waste water treatment efficiency

2019 ◽  
pp. 183-189
Author(s):  
Lijana Augulyte ◽  
Per-Anders Bergqvist ◽  
Audrone Zaliauskiene

One major result of implementing the Water Frame Directive (WFD) for the water industry is the likelihood of more stringent requirements for the efficiency of removal of the pollutants included in the list of WFD priority substances. During the last decade, an ongoing debate on the technical aspects of water treatment and on the fate and effects of its constituents after discharge are taking place. Due to the recent development of analytical techniques, the knowledge about the chemistry and toxicology of the waste water has increased considerable. Characterization of the oil treatment efficiency by total petroleum hydrocarbon concentration (TPH) is not sufficient any more. Waste water before and after treatment should be characterized by toxicity and amounts of the individual compounds and mixtures which trigger the toxicity. In the situations where more efficient oil removal from waste water is required to meet the requirements, there are a number of treatment options available, including some tertiary ("polishing") treatment systems. New generation tertiary wastewater treatment system for removal or reducing of the oil compounds, including dissolved polycyclic aromatic hydrocarbons, bearing along most toxic potential, was developed under a Eureka funded project. The new waste water treatment system involves novel monitoring device to verify that the dissolved and bioavailable fraction of the contaminants are degraded, and that the final effluent is cleaner also from a toxicity point of view. Previous studies showed that more toxic compounds might be produced during the treatment process due to the transformation of the original chemicals. The monitoring device consists of a membrane-based diffusive, time integrative (2-30 days) sampler. The newly developed fast analytical method for the analysis of membrane extracts enable to give us information on the dissolved concentrations for more than 80 oil related compounds in the effluents as well as the toxicity results, by using standard bio-assay tests. Moreover the monitoring system is capable to accurately sample most of the WFD priority substances in waste water treatment effluent waters. lt was found that some of the compounds were effectively removed in waste water treatment plant (WWTP), but other compounds remained in the dissolved phase at the same concentrations. Furthermore, volatilization of low molecular weight PAHs during the treatment process was studied by means of the new monitoring system, resulting in the identification of significant release of WFD pollutants to the air. The changes in time-integrative toxicity during the treatment process were evaluated by standard ecotoxicity analysis using the same membrane extracts. The three bio-assays used were Daphnia magna, Microtox and Algal but also other organism- or cell test systems will be tested further. Our developed monitoring device is the state-of-art method for screening for environmental toxicity by integrating biologically and chemically based techniques for early warning and ecosystem health assessment purposes. It can provide invaluable information in highly polluted environments where bioindicator organisms would not survive or behave normally.

1991 ◽  
Vol 24 (10) ◽  
pp. 161-170 ◽  
Author(s):  
M. D. Sinke

Until a century ago, The Hague's waste water was discharged directly into the city's canals. However, the obnoxious smell and resultant pollution of local waters and beaches then necessitated the implementation of a policy of collecting and transferring waste water by means of a system of sewers. By 1937, it was being discharged, via a 400 metre-long sea outfall, directly into the North Sea. By 1967, however, the increasing volume of waste water being generated by The Hague and the surrounding conurbations called for the construction of a primary sedimentation plant. This had two sea outfalls, one 2.5 km long and the other 10 km long, the former for discharging pre-settled waste water and the latter for discharging sludge directly into the North Sea. This “separation plant” was enlarged during the period 1986-1990. On account of the little available area - only 4.1 ha - the plant had to be enlarged in two stages by constructing a biological treatment section and a sludge treatment section with a capacity of 1,700,000 p.e. (at 136 gr O2/p.e./day). In order to gain additional space, a number of special measures were introduced, including aerating gas containing 90% oxygen and stacked final clarifiers. Following completion of the sludge treatment section, it has become possible, since 1st May 1990, to dump digested sludge into a large reservoir (“The Slufter”), specially constructed to accommodate polluted mud dredged from the Rotterdam harbours and waterways. As a result of these measures, there has been a reduction of between 70% and 95% in North Sea pollution arising from the “Houtrust” waste water treatment plant. Related investment totalled Dfl. 200 million and annual operating and maintenance costs (including investment charges) will amount to Dfl. 30 million. Further measures will have to be taken in the future to reduce the discharge of phosphorus and nitrogen. So this enlargement is not the end. There will be continued extension of the purification operations of the “Houtrust” waste water treatment plant.


1992 ◽  
Vol 25 (4-5) ◽  
pp. 225-232
Author(s):  
C. F. Seyfried ◽  
P. Hartwig

This is a report on the design and operating results of two waste water treatment plants which make use of biological nitrogen and phosphate elimination. Both plants are characterized by load situations that are unfavourable for biological P elimination. The influent of the HILDESHEIM WASTE WATER TREATMENT PLANT contains nitrates and little BOD5. Use of the ISAH process ensures the optimum exploitation of the easily degradable substrate for the redissolution of phosphates. Over 70 % phosphate elimination and effluent concentrations of 1.3 mg PO4-P/I have been achieved. Due to severe seasonal fluctuations in loading the activated sludge plant of the HUSUM WASTE WATER TREATMENT PLANT has to be operated in the stabilization range (F/M ≤ 0.05 kg/(kg·d)) in order not to infringe the required effluent values of 3.9 mg NH4-N/l (2-h-average). The production of surplus sludge is at times too small to allow biological phosphate elimination to be effected in the main stream process. The CISAH (Combined ISAH) process is a combination of the fullstream with the side stream process. It is used in order to achieve the optimum exploitation of biological phosphate elimination by the precipitation of a stripped side stream with a high phosphate content when necessary.


1996 ◽  
Vol 33 (12) ◽  
pp. 251-254
Author(s):  
Karl Arno Bäumer ◽  
Angela Baumann

The Institute for Water and Waste Management (ISA) at the Aachen University of Technology (RWTH) verified, through semi-technical analysis, the efficiency of the planned upgrade of the Kleve-Salmorth waste water treatment plant. Additionally the allowable biological phosphorus removal limit and the scheduled simultaneous precipitation were also ascertained.


2009 ◽  
Vol 55 (No. 2) ◽  
pp. 62-68 ◽  
Author(s):  
J. Kára ◽  
Z. Pastorek ◽  
J. Mazancová ◽  
I. Hanzlíková

The basis of the biogas production in agriculture is the processing of waste agricultural products (particularly excrements of farm animals but also phytomass). Different but rather similar is the biogas production from biologically degradable municipal waste (BDMW) and biologically degradable industrial waste (BDIW) coming mainly from food industry. The processing of these wastes in agricultural biogas stations could significantly improve their economy. It is necessary to note that all these biogas stations differ from the wastewater cleaning plants where municipal sludge water from public sewers is processed. The municipal sludge water processing to biogas by anaerobic fermentation is a classical technology introduced all over the world. At present, about 100 wastewater cleaning plants operate in the Czech Republic using regular sludge processing into biogas. Electricity produced is utilised mainly for the needs of own operation of waste water treatment plant (WWTP), partly it is sold into public power net. The heat energy is used for heating in the process and its surplus is utilised for operational and administrative facilities. Usually, the heat and electricity quantities produced do not cover the wastewater cleaning plant operation. Agricultural biogas stations and biogas stations for BDMW processing provide considerably higher gas yields because they work with higher dry matter contents in substratum, i.e. 8–12% (compared with waste water treatment plants – 2–6%), and are able to produce high gas surpluses for following applications. Frequently discussed issue are the processing of slaughter waste and grass (or public green areas at biogas stations).


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