The treatment of water and waste water by 100% sustainable CAFE solar powered filtration system:

https://cleanwaterwave.com/

Abstract

The CAFE (Clean Aqua For Everyone) filter was developed to help deliver safe clean water for rural communities in developing countries by Clean Water Wave CIC, a 100% asset locked social enterprise.

The filter was designed to provide drinking water in compliance to the European Directive from almost any water source. This also makes the CAFE filter applicable for the treatment of drinking water in Europe, or indeed any country around the world.

From the European Commission, there are 85,000 rural water systems in Europe serving 65 million people; 30% of the systems are non-compliant to the drinking water directive. More than 20 million people in Europe therefore receive potentially contaminated water.In order to stress test the CAFE filter, a unit was installed on a municipal wastewater treatment site near Edinburgh, Scotland, for the tertiary treatment of the final effluent. The water samples were taken and analysed by an accredited laboratories twice a week for a period of eight weeks, with a one week gap in the sampling.

There are many drinking water sources in Europe and around the world where the drinking water abstraction point is down-stream of a municipal waste water discharge. In order to ensure protection of the drinking water and public health, as well as the environment, tertiary treatment should be mandatory for all municipal waste water.

Tertiary treatment of waste water was not the intended end application for the CAFE filter; however the stability, reliability and performance of the filter at the testing site demonstrated that the process was applicable for the application of polishing the effluent for the removal of priority substances such as micro-plastics and priority chemicals including endocrine disrupters, pharmaceuticals and POPs (persistent organic pollutants). The filtered water produced by the CAFE filter was essentially in compliance with the European drinking water directive, confirming that a simple low energy solar powered filter using no chemicals or consumables has the potential turn municipal waste water effluent into drinking water.

Introduction

Municipal waste water facilities treat a combination of industrial and municipal wastewater. It is important that the water is treated to the highest possible standard in order to insure zero impact and sustainability of the environment into which the treatment plant discharges its effluent.

In order to comply with this performance statement, we should aim for either zero discharge, or zero impact on the environment and public health with regards to chemicals and substances such as plastic. Of particular concern are pharmaceuticals, lipid soluble priority chemicals and micro-plastics. The solution to pollution is not dilution: there is no safe discharge level for bio-active chemicals, or chemicals that are persistent in the environment. Plastic also contain POPs (persistent organic pollutants) such as:

• Oxybenzone
• Organic tin
• Heavy metals such as lead.

The concern surrounding plastic is that the micro particles are hydrophobic, and they will concentrate lipid soluble chemicals by many thousands or millions of times. The micro-plastics are then consumed by plankton and fish, or if they are sub-20nm in size, the particles will be absorbed directly through cell membranes. In this context there is no safe concentration because the plastic concentrates the chemicals and then inoculates marine life with a high concentration of the chemicals. 

1 in 15 of all marine organisms now contain micro-plastics. According to NASA, plankton, the root of the food chain, is currently dying at a rate of 1% year on year. We have already lost more than 50% of all marine plankton biomass, and at the current rate of decline, the marine ecosystem will experience a trophic cascade destabilisation over the next 25 to 30 years when the pH reaches 7.95. The marine ecosystem is the main driver for our climate, it is the source of most of our oxygen and is the main carbon sink for the planet. If we lose the marine ecosystem, then the terrestrial ecosystem will also experience failure. 

Currently less than 10% of all municipal waste water treatment facilities are fitted with tertiary treatment. Tertiary treatment is essential for removing lipid soluble hydrophobic chemicals and is a prelude to advanced photo-oxidation systems. More emphasis must be placed on the tertiary treatment of both industrial and municipal waste water in order to protect the environment, public health and help mitigate the impact of climate change.

“There is something profoundly wrong with the way we are living today. There are corrosive pathologies of inequality all around us — be they access to a safe environment, healthcare, education or clean water. These are reinforced by short-term political actions and a socially divisive language based on the adulation of wealth.”, Prof. Jacqueline McGlade, Executive Director European Environment Agency EEA Report No 1/2013

The results obtained for the CAFE filter with AFM (Activated Filter Media) have proved the process to be a robust and cost-effective technology. The cost of implementing CAFE has been assessed at approximately 30 to 100 Euro per person, PE population equivalent for both effluent treatment and for the provision of safe drinking water. Given the political will, there should be no barriers to the implementation of the technology.

Methods

The CAFE filter is a high-density polyethylene filter, all components in contact with the water are in compliance to DWI Reg 31, and NSF61. The filter media installed in the filter was AFMs (Activated Filter Media) grade 0, hydrophilic negatively charged and manufactured in accordance to ISO 09001-2015 in an HACCP certified factory. Hydrophobic non-polar AFM and positive charged activated AFM media are also available for different applications or for the removal of specific chemicals.

AFM filter media is a direct substitute for sand in any type of sand filter. AFM is manufactured by Dryden Aqua Ltd by up-cycling post-consumer glass bottles. The glass passes through a sophisticated physical process to remove organic and metal contaminants down to levels below 50ppb. The PSD particle size distribution and particle shape are controlled in order to insure optimum hydraulics and mechanical filtration performance. The surface structure is then altered to impart either a high negative surface charge potential, a non-polar surface, or a positive charged surface. The choice of AFM used depends upon the intended application. For the treatment of the municipal waste water, AFMs with a negative charge was used. There is no requirement to change the media: it will not biofoul, degrade or scale, and will have a life of 20+ years. The PSD is 250 to 500um particle size range.

The CAFE filter is a completely automatic self-back-washing media bed filter, with no moving parts or electrical control systems. The filter runs from a 4.5m water head or an 80-watt pump to deliver up to 2000 litres of water per hour and can be powered from solar panels. Filtration velocity is 2m/hr and back-wash velocity 40m/hr. The back-wash frequency is self-regulated by differential pressure: the higher the suspended solids concentration, the more frequent the back-washing. Typically, the back-wash frequency was once every 8 hours for the municipal waste water.

Water samples were collected on a Monday and Thursday morning at the same time and taken to an accredited laboratory for independent analysis. The ISO A2 laboratory colloidal silica tests were conducted by Dryden Aqua. Microplastic analysis in the raw water and filtered product water was conducted by Dryden Aqua.

TSS total suspended solids was determined by filtration at 1.2um; this is a standard procedure. However, AFM in the CAFE filter is actually filtering considerably better than 1.2um. For example, the CAFE filter was able to treat the waste water containing over 0.5 million bacteria and reduce the concentration to zero, with no chemicals or UV irradiation being employed. The CAFE filter is therefore removing more and smaller suspended solids than can be measured by the laboratory procedure. The suspended solids results presented by the laboratory are therefore an under estimate.

The water flow per filter is 2m3/hr; if more water is required then a multiple number of units may be employed. For much larger systems AFM may be used as a direct replacement for sand in simple RGF rapid gravity filters. AFM can be applied for this application because unlike sand, AFM will not experience bio-coagulation, transient channelling or bed blockage. 

The technology is robust, scalable, future proofed and economic. If sand is already used for the application, then AFM will perform many times better than the sand.

Results

Bacteriological results

Out of thirteen results, with the exception of one result, the CAFE filter reduced the concentration of coliform bacteria in the product water, and eight of the results showed that the CAFE filter removed 80% or more of the bacteria. The results followed a similar pattern for E.coli and Enterococci. There was no chlorination, oxidation chemicals or UVc systems applied, yet on three occasions the CAFE filter was able to reduce the Coliform bacteria count to zero bacteria per 100ml.

BOD

The upper limit of detection was 16mg/l; all readings above 16mg/l are shown as 16mg/l. The lower limit of detection was 2mg/l; all values below the limit are shown as 2 mg/l. The municipal wastewater treatment plant is stable and has a high performance, and as such there is usually not a requirement to measure BOD above 16 mg/l.

The percentage reduction of BOD relates directly to the concentration of BOD in the raw water; it is also a function of the concentration of BOD in the product water. Out of 14 results, only one of the results from the CAFE filter product water was above the limit of detection.

The CAFE filter reduced the BOD in 100% of the samples; where the concentration was above the limit of detection, more than 50% of the results gave a 50% reduction in BOD, and when the feed concentration was higher than 10mg/l, the CAFE filter gave an 80% reduction of BOD. The percentage reduction would be better if the limit of detection was reduced to reflect a more precise value for BOD in the CAFE filter product water. 

Metals

Apart from the alkali earth metals, aluminium was the only metal that was detected in the waste water from the water treatment system. With the exception of one result, the CAFE filter reduced the concentration of aluminium in the final effluent. The percentage removal was a function of the influent concentration. When the concentration of aluminium exceeded 50 ug/l in the raw water, the CAFE filter reduced the concentration by more than 50%.

PolyCyclic Aromatic Hydrocarbons PAHs

Polycyclic Aromatic Hydrocarbons (PAHs) are a group of organic compounds containing 2 or more fused aromatic rings of carbon and hydrogen atoms. The chemicals tend to be very stable; there is scope for bio-accumulation as they are non-polar and hydrophobic and will be bound up on micro-plastic and bacterium cell biomass.

There are many compounds in this group; for determining compliance with the Drinking Water Regulations, five of the PAHs are considered:

·      benzo(a)pyrene 0.01ug/l

·      benzo(b)fluoranthene 0.03 ug/l

·      benzo(k)fluoranthene 0.03 ug/l

·      benzo(ghi)perylene 0.03 ug/l

·      indeno(1,2,3-cd)pyrene 0.03 ug/l

PAHs originate from many sources including coal-tar coating of drinking water pipes, vehicle emissions and the combustion of fossil fuels.

This group of compounds are carcinogens and are implicated in cardiovascular disease.

Total PAHs

In 100% of the results, the CAFE filter reduced the concentration of Total PAHs. There were 10 complete sets of data, and with 6 of the data sets the percentage reduction exceeded 50%. Performance is related to concentration: the higher the concentration of the PAHs in the feed water, the better the performance of the CAFE filter.

The upper limit for drinking water is 0.1ug/l: the CAFE filter therefore brought the product water into full 100% compliance with the European Water directive with regards to total PAHs.

Benzo(a)pyrene

11 data sets, five of which showed more than 70% removal of the PAH. The upper limit for drinking water is 0.01 ug/l so two of the results from the wastewater treatment facility were not in compliance to the European drinking water standards. However, all of the results after passage through the CAFE filter 100% were in compliance.

benzo(b)fluoranthene

11 complete data sets are available; eight of the data sets gave better than 50% removal of benzo(b)fluoranthene, and with the exception of one result the CAFE filter reduced the concentration of the chemical. Upper limit for drinking water is 0.03ug/l; all water quality results are therefore in compliance. While the concentrations were very low in the effluent, the CAFE filter was able to provide a 50% reduction and reduce the concentrations to an average figure of 0.002 ug/l, or less than 10 times the concentration permitted in drinking water.

benzo(k)fluoranthene

The removal of benzo(k)fluoranthene was excellent; with the exception of two results, the CAFE filter reduced the concentration of the chemical by more than 50% in seven out of 12 complete data sets. The upper limit for drinking water is 0.03 ug/l, so all of the water quality results are in compliance and present at very low concentrations. The CAFE filter was able to demonstrate a 50% reduction of the concentration of most of the water samples.

benzo(ghi)perylene

Out of 10 complete data sets, the CAFE filter removed benzo(ghi)perylene in nine of the data sets, and 7 of the data sets gave better than 50% removal.

indeno(1,2,3-cd)pyrene

11 complete data sets; with the exception of two results, the CAFE filter reduced the concentration of indeno(1,2,3-cd)pyrene in the final effluent. Six of the results gave better than 50% reduction and four gave better than 90% reduction.

Anthracene

Anthracene is considered as a priority chemical (see Directive 2013/39/ EU of 12 August 2013). The chemical is used as a precursor for dyes and should not be allowed to enter the environment due to its high level of toxicity.

12 complete data sets in which the CAFE filter reduced the concentration in 10 samples.

The following table lists the remaining PAHs tested for the CAFE filter trial. There were inconsistencies due to analytical interference which made it difficult to precisely measure the chemical parameters when present at the low parts per billion. However, more than 80% of all samples taken demonstrated a reduction in the chemical parameter on passage through the CAFE filter; the actual number of data sets where there was a reduction in the chemical parameter on passage through the CAFE filter are listed in the table below. Also listed are the number of data sets that achieved better than 50% reduction and 90% reduction.

Semi Volatile Organic Carbon SVOC

The CAFE filter demonstrated excellent performance for the removal of SVOCs. In all cases the CAFE filter reduced the concentrations to below detection level, with a performance for many of the parameters in excess of 90%.

Oestrone (e1)

13 complete data sets, with the exception of three results, the CAFE reduced the concentration of the female hormone. Seven of the results gave better than 50% reduction and five of the results were better than 90% reduction.

Petroleum Hydrocarbons

The data set for petroleum hydrocarbons is incomplete; however from the complete data sets, the CAFE filter removed more than 70% of the hydrocarbons from the wastewater.

Turbidity

12 complete data sets and, with the except of one result, the CAFE filter reduced the turbidity of the waste water, and six of the results gave better than 50% reduction.

The product water turbidity was constant, whereas the raw feed water from the municipal waste water treatment plant demonstrated instability. The percentage removal is a function of the feed turbidity level: the higher the concentration, the better the performance of the CAFE filter.

The suspended solids concentrations tracked the turbidity levels, but 100% of the suspended solids values were reduced by the CAFE filter, and nine of the 12 complete data sets gave better than 50% reduction of suspended solids.

Colloidal Silica

The performance of the CAFE filter was also determined under controlled laboratory conditions for the removal of ISO A2 silica particles. The filtration performance was determined by particle size analysis of the water before and after the filter. The pressure differential was also measured across the filter bed.

The CAFE consistently removed more than 99.9% of all particles down to 2um. The tests were conducted by Dryden Aqua Ltd. Independent verification at higher flowrates are also available from IFTS (Institute of Filtration and Technical Services) in France.

Micro-plastic

The ability to remove micro-plastics in the form of micro-beads, fibres and films is becoming increasingly important. Plastic is now found in most of our drinking water: on average up to eight particles will be present per litre of water, and it is present in all of our wastewater to varying concentrations from less than one particle per litre to many thousands per litre.

Plastic contains toxic chemicals such as plasticisers and UV stabilisers, and they can also adsorb toxic chemicals such as lipid soluble persistent organic pollutants. It is therefore essential that we remove these substances from all of our water supplies and the environment.

The performance of the CAFE filter was tested by Clean Water Wave CIC under controlled conditions for the removal of 6um acrylic plastic beads. The feed water was spiked up to a concentration of 4000 particles/ml and water tested by a particle size analyser. Acrylic has the same refractive index as water, so a range of particle sizes were measured; however more than 90% of the particles were between four and eight microns in size, and the CAFE filter removed in excess of 99.8% of the particles from the water with no requirement for flocculation or coagulation chemicals. Removal of the particles is by adsorption as opposed to mechanical filtration. 

Samples of water were collected before and after the CAFE filter for plastic analysis. Samples were collected in 1 litre glass bottles with metal top in order not to add any possible plastic to the samples. The work is still on-going and is being conducted by Clean Water Wave technicians in accordance to the procedures detailed by Blair et al (2019, March 12). 

The water samples containing the plastic was treated with hydrogen peroxide at 75 deg C for 30 minutes and then stirred and digested for 3 days in order to completely oxidise organics. The process would also pasteurise and disinfect the water samples.

The water samples were then filtered through 1.2 um Whatman glass papers and inspected under a microscope at 30 to 90 magnification.

Samples of water are taken from the product water, feed water and back-wash water from the CAFE filter. The run-phase duration is known, and back-wash volume is known: analysis of the back-wash water therefore provides a composite result over the period of the run phase which is typically 8 hours. The results to-date give a range of <5 particles per litre to >1000 per litre entering the CAFE filter from the waste water treatment facility. 

No plastic has as yet been detected in the product water from the CAFE filter. Analysis is on-going and the results will be up-dated as data becomes available.

The photographs on the right are 1.2 um filtered water samples of the product water, effluent feed water to the CAFE filter and back-wash water from the CAFE filter.

Note that there are no detectable particles shown for the product water, the CAFE filter is removing most of the particles, so the filter paper appears clean. The feed water supply (final effluent from the wastewater treatment facility) contains solids and has discoloured the filter paper.

The back-wash water contains a high concentration of solids and is the main sample source for checking the plastic content of the water as it relates to a composite sample over an eight hour period. 

Plastic fibres

Plastic fibres represent approximately 80% of all micro plastic found in waste water. The fibre in photo 4 measures 10 um in width and approx. 1000 um in length.

Triclosan

13 complete data sets; 10 results gave a reduction of Triclosan and for three results the percentage removal was better than 90%.

The 96‐h NOEC (no‐observed‐effect concentration) for Scenedesmus algae was 0.69 μg/L (David R. Orvos et al 05 November 2009); however the chemical has scope for bioaccumulation and over a longer time frame and with biological inter-reactions the NOEC would be expected to be a much lower concentration. The CAFE filter was able to reduce the concentration of the Triclosan from concentrations as high as 0.24 ug/l down to 0.005ug/l. The chemical is a known endocrine disrupter; it is linked to cancer, and bacteria can develop resistance to the product. It is therefore important that we use safer options, and implement technology to reduce of prevent the discharge of the chemical into the environment.

Discussion

Bacteria and Phosphate

The CAFE filter is a media bed filter using grade 0 AFMs filtration media. AFM media will mechanically remove particles above 20um, but all particles including planktonic bacteria are removed by adsorption below 20 um. The effluent treatment trials did not use any disinfectants, oxidising agents or UV irradiation or any means other than passage of the water through the filter bed, yet on three occasions bacteria concentrations dropped to zero coliforms per 100ml. This has been achieved by the physically removal of the bacteria from the water.

When the CAFE filter is back-washed the bacteria are discharged in the back-wash water and returned to the beginning of the effluent treatment facility. Priority chemicals and toxic substances will be preferentially bound up on the surface of micro-plastics and on the surface and internally within the bacterium cell biomass. It is therefore very encouraging to note that the CAFE filter was reducing the bacterium level by more than 80% for most of the samples and by 100% for 20% of the samples.

The CAFE filter may be used in combination with coagulants / flocculants such as polyamide or PAC, to further improve the mechanical filtration performance of the process. Ferric chloride may be used if there is also a requirement to reduce the orthophosphate, arsenic or manganese concentration. The oxidation potential prior to CAFE may be increased prior to filtration to reduce the ZETA potential and promote flocculation; this may be achieved with no chemicals using a static mixer such as a ZPM from Dryden Aqua, or by the addition of an oxidising agent such as hydrogen peroxide, ozone, chlorine dioxide or hypochlorous to raise the oxidation potential by 100mv.

BOD

The CAFE filtered reduced the total BOD (Biological Oxidation Demand) to below detection level of 2 mg/l, with the exception pf one result which was 3 mg/l. The influent concentration ranged from the LOD (limit of detection) at 2mg/l to the upper limit of detection at 16mg/l. The percentage removal of BOD was therefore linked to the influent concentration, because the product water concentration was a constant.

The results demonstrate that the CAFE filter is an effective means of reducing BOD of municipal waste water.

Heavy metals

The concentration of metals was very low in the waste water; indeed, all metals with the except of Calcium, Magnesium and Aluminium were below detection. The aluminium concentrations range from 30ug/l to 80ug/l in the waste water and the CAFE filter consistently reduced the concentration to 20 ug/l.

The filter media AFMs carries a surface negative charge and is therefore able to adsorb multivalent cations such as aluminium very effectively. The process may also be used for the removal of Arsenic, Manganese and Ferric, either directly from solution or more commonly as a co-precipitated colloidal metal oxide micro-particle.

PAHs Polycyclic Aromatic Hydrocarbons

These hydrocarbons are derived from the incomplete combustion of fossil fuels and many of them are cancerogenic and implicated in cardiovascular disease. Five chemicals are of particular concern and are routinely monitored for drinking water compliance:

·      benzo(a)pyrene

·      benzo(b)fluoranthene

·      benzo(k)fluoranthene

·      benzo(ghi)perylene

·      indeno(1,2,3-cd)pyrene

The molecules are uncharged, non-polar and hydrophobic; it would therefore be anticipated that non-polar hydrophobic AFMng wold be a better choice in the CAFE filter if it were a requirement to focus on the removal of this chemical group from the water.

The total PAHs and Benzo(a)pyrene discharges from the wastewater treatment facility were not in compliance when measured against the European Drinking water standards; however the product water from the CAFE filter was in 100% compliance with regards to all PAHs.

While the concentrations in the waste water treatment facility were extremely low, when plants and animals are exposed to chemicals over a long period of time, there is scope for bio-accumulation and when the chemicals are mixed with other chemicals including pharmaceuticals, it is not possible to predict the toxicity or the environmental implications of the discharge. For this reason, the object must also be to try and achieve zero discharge or reduce the concentrations for zero impact. The CAFE filter has demonstrated that it would be a useful process that would help water companies to meet the highest possible standards.

SVOC semi volatile organic carbon

Semi volatile organic carbon is considered a sever threat to environmental as well as public health (see Zekai Li et al, May 2018).

During the laboratory were successful in achieving one full set of data for the influent and product water from the CAFE filter. The data is presented in the results section. All of the results confirmed that the CAFE filter reduced the concentration of all the chemicals to below the LOD limit of detection at 0.2 ug/l.

DIRECTIVE 2013/39/EU OF THE EUROPEAN PARLIAMENT identified certain sVOC as priority chemicals; they include the following; items with a tick were measured in the current trial.

•     Anthracene
• Di(2-ethylhexyl)phthalate
• Endosulfan
• Hexachlorobenzene
• Hexachlorobutadiene
• Hexachlorocyclohexane
• Pentachlorobenzene
• Polyaromatic hydrocarbons (PAH)
•     Trifluralin
• Dicofol
• Quinoxyfen
• Hexabromocyclododecanes
•     Heptachlor
•     Heptachlor epoxide

 “Chemical pollution of surface water poses a threat to the aquatic environment, with effects such as acute and chronic toxicity in aquatic organisms, accumulation of pollutants in the ecosystem and loss of habitats and biodiversity, and also poses a threat to human health. As a matter of priority, causes of pollution should be identified and emissions of pollutants should be dealt with at source, in the most economically and environmentally effective manner.”, Directive 2013/39/EU.

Drinking water standards

The quality of drinking water sources in developing countries may approach the quality of the water discharged from Bo’ness waste water treatment plant. The performance of the CAFE filter product water was compared against WHO and European Drinking Water directives. The CAFE filter product water was in compliance to the drinking water standards with a few exceptions.

a.    The wastewater was subject to salt water intrusion which increased the conductivity, TDS and chloride concentration. Normally this would not be a problem for most treatment plants; however, the proximity of the Bo’ness facility to the sea (Forth Estuary) resulted in the intrusion. The CAFE filter cannot be used for desalination, but it can be used for pre-treatment of the water prior to membrane desalination.

b.    Ammonium: the CAFE filter with AFM is a non-biological process and as such there will be no heterotrophic bacterial assimilation or autotrophic nitrification of ammonium; the technology therefore cannot be used for ammonium reduction.

c.    The bacteria analysis for Coliforms confirmed that on three occasions the media bed filter reduced the bacteria concentration to zero with no disinfection. The zero bacteria levels were achieved purely by the filtration process. With the addition of chlorination or CW Gen oxidation of the CAFE filter product water would have been in compliance with bacteriological standards.

Conclusions

The CAFE filter has been designed to be a very simple filter with no moving parts, valves, or control systems. There is therefore very little with the system that can fail. One of the primary reasons for the trial on a waste water treatment facility was to stress test the filter. The trial confirmed that the CAFE filter could be left unattended, and that it was able to cope with the bacteria cell biomass and varying water quality conditions typical of final effluent municipal wastewater. Over the period of the trial, and subsequent weeks while the filter was left unattended to operate on the site, the CAFE filter completed over 1000 back-wash cycles. The only time operator support was required was during periods when the municipal wastewater treatment facility was experiencing mechanical or biological problems.

On the basis of the results achieved, and with the exception of the salt intrusion and ammonium in the water, a CAFE filter fitted with disinfection would be able to deliver water in compliance to the European drinking water standards from a municipal wastewater. 

Laboratory tests confirmed better than 99% filtration down to 2 um, and bacteriological results of zero, confirmed that the CAFE filter is providing excellent mechanical filtration and that it is not becoming a biofilter. 80% of disease in developing countries is caused by the consumption of contaminated water, and 60% of the disease incidents are because of parasites such as Cryptosporidium at 4um size. The CAFE filter will be able to deal with this organism, and because the water will be mechanically very clean, disinfection using the solar powered CW Gen or by chlorination should be a simple task.

The laboratory trials and field results demonstrate that the CAFE filter can remove mirco-plastics down to 6um with a performance better than 99%. The filter also demonstrated a good performance at removing priority chemicals including Polycyclic Aromatic Hydrocarbons and semi Volatile Organic Carbon. Indeed, the CAFE filter reduced all of the SVOC values to below detection level. In order to protect public health as well as the terrestrial and marine ecosystem, we must aim for zero discharge or zero impact. It is not a sustainable situation to continue to discharge toxic chemicals such as POPs (persistent organic pollutants) into the environment. The CAFE filter with AFM activated filter media provides a cost-effective technology to help achieve this task.

The CAFE filter has proved to be a robust, efficient and cost-effective solution for the tertiary treatment of municipal waste water, and given that that the product water quality was essentially in compliance with European drinking water standards, there is high confidence that the CAFE filter will be able to provide safe clean drinking water from almost any source in developing countries.

References

Blair, R. M., Waldron, S., & Gauchotte-Lindsay, C. (2019, March 12). Average daily flow of microplastics through a tertiary wastewater treatment plant over a ten-month period. https://doi.org/10.31223/osf.io/ez5gm

David R. Orvos et al (05 November 2009) Aquatic toxicity of triclosan https://doi.org/10.1002/etc.5620210703

Zekai Li May 2018 Occurrence and potential human health risks of semi-volatile organic compounds in drinking water from cities along the Chinese coastland of the Yellow Sea Chemosphere 206 · DOI: 10.1016/j.chemosphere.2018.05.064

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32013L0039: Directive 2013/39/ EU of 12 August 2013 amending Directives 2000/60/EC and 2008/105/EC as regards priority substances in the field of water policy.

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32015L1787: Commission Directive (EU) 2015/1787 of 6 October 2015 amending Annexes II and III to Council Directive 98/83/EC on the quality of water intended for human consumption.

https://ec.europa.eu/environment/water/water-drink/small_supplies_en.html The status of rural community drinking water

https://ec.europa.eu/environment/water/water-drink/pdf/Small%20drinking%20water%20supplies.pdf Framework for Action for the management of small drinking water supplies

EEA Report No 1/2013 Late lessons from early warnings: science, precaution, innovation, ISSN 1725?9177

The CAFE filter story

A report for the European commission states that 20 million people in Europe do not have water that is consistently in compliance to the Drinking Water Directive; this equates with 3% of the population of the European Community. Not all municipal drinking water treatment facilities are 100% effective. Disease associated with the consumption of drinking water in Europe is therefore estimated at 5% of all disease contracted by the population. In low income countries across Africa and Asia, the incidence of disease from the consumption of contaminated drinking water is as high as 80%.

Dr. Howard Dryden of Dryden Aqua was part of a European Consortium, Eco-India, funded by the European commission under the FP7 program to help develop technology that could treat surface water such as the River Ganga to provide clean safe drinking water. he greatest human poisoning in history is on-going in India and Bangladesh and it’s getting worse: arsenic poisoning from the consumption of ground water. The communities with whom we were working had an average income of 1 to 2 Euro/day and spent 25% to 50% of this income in buying bottled water in plastic containers. It is not difficult to treat water and make it safe, but technologies that use UV, ozone, membranes, control panels & PLCs have almost a 100% failure rate after 12 months because the local communities cannot operate the systems, repair the equipment when it fails, or afford to replace the consumables such as membranes.

The CAFE filter was therefore developed as a media bed filter using grade 0 AFM in the CAFE filter to provide a completely automatic system, with no moving parts or valves, and with the ability to back-wash at a precise differential pressure without wasting water. The CAFE filter has now been tested with over 1000 back-wash cycles and it has performed perfectly. AFM is manufactured by up-cycling post-consumer glass bottles to develop a media that performs much better than sand for the removal of <10 um particles. In addition, the media never needs to be changed: once it is in the filter, it will continue to perform for more than 20 years.

The CAFE filter was developed to provide clean safe water for this communities in developing countries that are most in need. CAFE filters are manufactured by Clean Water Wave, a social enterprise that is 100% asset locked. This means that all the profits from the company go back to delivering clean water for those most in need. The stress testing of the technology on municipal waste water systems in Scotland confirmed that the technology was very well suited for the application. An option has now developed to apply CAFE filter technology for the elimination / reduction of pollution from industry and municipal waste water sources. Profits from the sale of the technology can then be applied to deliver on the primary objective to give clean safe drinking water to those moist in need and to try and reduce the number of plastic bottles produced.

In addition to treating waste water, the CAFE filter is perfect for delivering clean drinking water for rural communities in Europe and other developed countries.

Applications for CAFE filter technology:

Clean water

1.    Rural community and peri-urban communities in developing countries

2.    Rural community drinking water in Europe and developed countries

3.    The provision of clean water for farm animals and agriculture

4.    The provision of clean water for irrigation and aquifer replenishment

5.    Pre-treatment of seawater or brackish water, prior to RO membranes

Waste & process water

1.    The removal of plastic micro-particles, beads, fibres and films

2.    Tertiary treatment of municipal waste water

3.    Tertiary treatment of almost any water after a biological process

4.    Cooling tower recycle water