Büro für Altlastenerkundung und Umweltforschung

Dr. Rainer Haas

Stadtwaldstr. 45a, D-35037 Marburg, Tel.: 06421/93084, Fax: 06421/93073

email: haasr@gmx.net

Water Purification by Impregnated Paper

Franz D. Oeste ¹⁾, Rainer Haas ²⁾, Lothar Kaminski ³⁾

¹⁾ gm-Ingenieurbüro, Tannenweg 2, D-35274 Kirchhain
²⁾ Büro für Altlastenerkundung und Umweltforschung, Stadtwaldstraße 45a, D-35037 Marburg
³⁾ Institut für Immunologie, Bereich Umwelthygiene, Pilgrimstein 2, D-35037 Marburg

Abstract

We found a new and easy way of water treatment to reduce arsenic and heavy metals. This may be done by all possible kinds of contacting contaminated water with impregnated paper. About ninety percent of the contaminants or even more may be sorbed by only one treatment step. Water treatment may be done by suspending impregnated paper chips and separation of the chips after suspension by simple screening of the treated effluent to seperate the used chips. Fixed beds of impregnated paper may also be used for water cleaning.
We recommend this kind of water treatment for all kinds of arsenic and heavy metal contaminated kinds of water including industrial waste waters. We see special advantages for decontamination of private well waters, surface waters, tap water because water treatment can be done with very low grade „technical” means. This may give a good chance to those many people who suffer so much by highly contaminated drinking water. Especially we hope that our findings may help people in Bangladesh which suffer from high arsenic drinking water contamination.

Keywords: arsenic, copper, lead, heavy metals, water purification, sorption

1 Introduction

Water contaminants by arsenic and heavy metals in ground waters and surface waters as drinking water sources, in house drinking water, mine drainage waters and industrial or municipal sewage may cause problems to men and environment. Especially those groundwater drainage areas which have a high natural arsenic content or heavy metal content may cause problems when those waters are used as drinking water without treatment. Those problems especially according to arsenic are known from several asian countries, for instance Bangladesh. Also European areas located to Alpine regions are known to be highly contaminated with arsenic. Even some mineral water springs in Germany and other countries have high levels of arsenic. Similar problems exist with some geogenic enriched heavy metals which may contaminate private wells as well as municipal wells for drinking water use. Known problems exist with lead and nickel.

Some well known water treatment operations are existing to eliminate these problems. A well known operation is ion exchange.

This is an expensive operation which economical can not be used to decontaminate large volumes of water. Especially the ion exchange process may present damage to the environment and health problems to men because of its high waste production and leaving a clean water which is depleted in the essential alkaline earth elements. Another possible operation is sorption of heavy metals at activated carbon.

Because of their small sorption capacities the carbon based decontamination is not economical. Good treatment results concerning heavy metals and arsenic have been found with fixed bed filters containing filter particles coated by iron oxides. The last mentioned and well known operation may be useful for municipal or industrial purposes. Because of its high complexicity it can not be transferred to surface water or well water decontamination in private households.

To overcome these difficulties we developed special coated highly sorptive impregnated papers. Their removal capacity for cationic contaminants in water has been tested by us. Here we present the results of our tests. These results encourage us to recommend the impregnated paper for water purification of all kinds of uses but especially for private and municipal use.

2 Experimental

Commercial coffee paper filters (trade mark „eduscho”) have been impregnated by a multi stage operation with iron salts. The resulting paper filters with oxidic impregnation showed high sorptive capacity. With model waters of a known content of contaminants the filters have been tested. For analytical investigations of the treated and untreated model waters with respect to the contaminants arsenic, copper, lead and nickel we used atomic absorption spectroscopy (AAS).

1) Simulation of drinking water treatment by sorption

By doting of deionized water with kationic standard solutions we produced model water A. It contained 1910 µg/l copper, 100 µg/l nickel, 120 µg/l lead and 4.5 µg/l arsenic. By the same way we produced three more model waters: Model water B contained 100 µg/l arsenic,Model water C contained 1000 µg/l arsenic, and Model water D contained 10000 µg/l arsenic.

1.1) 1 cm x 1 cm impregnated filter paper chips where cut of the coffee paper filters. 0.8 g filter paper chips were added to 250 ml model water A. Not incontinously the mixture has been shaken. After 24 h the mixture was poored over a tea screen to seperate the impregnated paper.

1.2) In each case 0.8 g of the 1 cm x 1 cm impregnated filter paper chips were added to in each case 100 ml model waters B, C and D. Not incontinously the mixtures have been shaken. After 1 h, 2.5 h, 4 h, 6 h, 24 h and 48 h in each case arsenic content within a seperated model water sample has been investigated.

2) Simulation of drinking water treatment by filtration

500 ml of model water A has been filtered two times through one impregnated coffee paper filter. For both filtration operations the same coffee paper filter has been used. Every filtration operation lasted about 2 minutes.

3) Simulation of industrial waste water treatment by fixed bed filtration

Within a 5 cm diameter inside glas pipe 10 g of the 1 cm x 1 cm impregnated filter paper chips have been fixed between cotton wad. The wetted fixed paper filter bed hight was about 5 cm. Model water E was passed from bottom to top of the fixed bed filter in a transfer rate of 3.5 ml/min. Model water E had a pH of 9.9. It originated from an industrial accumaulator production plant and contained 110 mg/l lead and 1000 mg/l sodium salt of humic acid. After a throughput of 250 ml the following quantity of 50 ml have been analyzed.

3 Results, discussion and recommendations

Test results of water treatment test 1.1) with the impregnated paper filter chips are shown in table 1. All reduction rates exceed 95 %.

Table 1: Results of water treatment test 1.1); model water A

Test results of water treatment test 1.2) with the impregnated paper filter chips and heavy arsenic contaminated water after reaction period of 24 h are shown in table 2. Reduction rates all exceed 80 % in a single step process.

Table 2: Results of water treatment test 1.2); model waters B, C and D

Test results of water treatment test 2) with the impregnated coffee filter are shown in table 3. Because of the extreme short contact time of model water A with the filter the contaminant reduction rate is lower than in all other tests. But the reduction is significant and exceeds 60 % for lead. Results are collected in table 3.

Table 3: Results of water treatment test 2); model water A

Test result of test 3) with a high lead loaded industrial waste water in the presence of complexing agents resulted in comparison to the other test results in the relative low contaminant reduction of 42 %. Reasons like low filter bed hight, big sized paper chips with only 5 times the bed diameter of the filter bed, high load of the lead complexing agent humic acid salt, reactivity of the humic acid salt with the iron oxide content of the paper impregnation may be responsible for the lower contaminant reduction rate.

We have shown that our arsenic and heavy metal sorbing papers are very effective in water purification. Our papers may be used with a efficient at a very low grade process standard. This encourages us to recommend the use of this impregnated papers for purification of arsenic and heavy metal polluted drinking water especially in areas without or very low grade municipal systems for water purification. Especially we recommend the use of the papers for private homes, villages and towns in those not so highly developed areas.

The tested impregnated filter paper only contain natural cellulose fibers and mineralic iron-III-compounds. Tests showed, that no in any way harmful substances or iron salts could be extracted from our impregnated papers.

The following low tech procedures are recommended by us to clean drinking water by our sorbing paper with high decontamination efficiency.

Treatment of the drinking water may be done in every simple containment. These may be drums, tanks, plastic foil sealed containers, boxes, excavations etc. Impregnated paper pieces may be poured into the water filled containments.

From time to time the paper pieces have to be prevented from settling or sedimentation. (investigations are under way developing special varieties of impregnated paper with gravities close to water, to prevent sedimentation) This can be done manual or by natural means. Natural means are the sun induced heating of the containment on one side, for instance by black color, to induce convection. Another possibility is to get motion into the stored drinking water by a small wind driven stirrer.

We recommend to separate the sorbing paper after max. two days of treatment because of the organic nature of the paper to prevent developement of microbical action. This could lead to microbiological induced reduction. Reduction has to be prevented because the paper bound contamination could be redissolved by this. This is the reason we recomment too good contact of the drinking water to the atmosphere to keep it or to transform it by oxygen dissolution in an oxygenated status.

The separation of the sorbing paper can be done too by very simple means. One possibility is a net with meshes smaller than the paper pieces. The net is placed closely to the containment walls. After sufficient treatment time the net together with the paper pieces may be lifted. Up and down lifting of the net will allow additional possibilities of sedimentation prevention of the paper pieces.

The low grade technic which we recommend for drinking water decontamination will enable everyone to clean household and office tap water in the so called developed countries too. Deriving from copper and lead pipes, solder and possible other locations. Nothing more than the sorbing paper and a small screen which is useful for tea preparation is needed.

4 Literature

[1] Oeste, F.D., Haas, R. (1998): Filterpapier für die Wasserreinigung. Patentanmeldung v. 20.4.98, Az.: 19817395.4

[2] Oeste, F.D., Haas, R. (1998): Imprägnierte Fasermaterialien zur Wasser-, Getränke- und Nahrungsmittelreinigung. Patentanmeldung v. 16.9.98, Az.:19842528.7

[3] Oeste, F.D., Haas, R. (1998): Verfahren zur Wasserreinigung durch Rein-Tauchen. Patentanmeldung v. 16.11.98, Az.: 19853158.3

You can get more informations about our impregnated papers. Please write a email (haasr@gmx.net).

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