AU2003244617A1 - Reverse integrated separation system for alleviating water shortages at advanced level - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Reverse Integrated Separation System for Alleviating water shortages at Advanced Level The following statement is a full description of the invention, including the best method of performing it known to me Background to the invention WATER is being drown from rivers, dams, underground reservoirs, lakes, and sometimes from the sea, for treatment, distribution and use. The distribution of water to the main sectors depends on the country, its type of economy, its development stage, climate, rainfall regime and distribution, etc.. In most of developed countries, the main sector using water is the agriculture while the rest is divided between urban, industrial, domestic and rural users.

In Australia, 74% of the fresh water is used in agriculture, after which, the water is '"lost" to ground penetration, or overflow into rivers or lakes.

Most of the remaining 26% of fresh water is transformed into industrial or domestic effluents, which should be treated and made suitable for discharge.

Thus, water from the source, is being treated at least once to make it suitable for users (water treatment) and once again, to make suitable for discharge (wastewater treatment).

Water treatment seems to be simpler than the wastewater treatment because of: -large diversity and complexity of waste water streams, each one demanding a tailor made system design compared with the almost "standard" water treatment.

-level of "polluting" ingredients in the wastewater streams, compared with relatively small amounts of "contaminants at low concentrations" in water streams.

One could divide all technologies used in either water or wastewater treatment into five major categories: Conditioning Unsegregated separations Targeted purifications Biological treatment SPathogen removal disinfection.

There is no set order in applying technologies belonging to these categories of treatment, as there is no restriction on using certain technologies or unit operations repeatedly.

Conditioning includes all technologies and operations that lead to a certain condition to be created in that stream.

pH adjustment is used widely for metal ions precipitation creating the right conditions for nutrient removal in biological WWT, iron and manganese removal in water treatment, scale prevention in heat exchangers and reverse osmosis This is done by addition of chemicals with acidic or alkaline properties.

Caustic soda and acids, as well as lime, lime of magnesia, carbon dioxide, are used for dosing streams.

Chemical additions other than for pH adjustment, includes all the flocculants, organic and inorganic used to facilitate the creation of aggregates which will later precipitate taking with them (co precipitate) a few of the pollutants.

In this category are also the chemicals used to oxidize or reduce chemical compounds (Chromates, Cyanides, Iron which in turn, will be easily removed later on.

It also includes micro nutrient dosing into biological systems lucking them, and all conditioning chemicals used to prevent scaling, corrosion and slime in water recirculation systems.

Air and carbon dioxide introduction into stream to facilitate bacterial growth and sustain biological systems, to prevent anaerobic conditions developing, to prevent scaling and aggressiveness (corrosion), to extract other gases and compounds (THM's), Nitrogen injection to prevent bacteriological developments in highly purified water, they all belong here, to conditioning.

Some of the chemicals used for disinfection (Chlorine, Ozone, Hypochlorite, Chlorine Dioxide) could be included in this category as well.

Unsegregated separations are all those technologies and unit operations used to separate in bulk, according to certain physical conditions (density, size).

All precipitations, sedimentations screenings, filtrations, flotation, decantation, centrifugation, thickening of sludges, devices and process, belong to this category of water and wastewater treatment.

All evaporative, freezing, and pressure driven membrane separation systems used in desalination belong here Cyclone and vortex type devices for solid liquid separation belong here as well.

Targeted purifications include the technologies, processes, operations and means used to separate a certain type of ingredient or family of ingredients.

Activated carbon is used to absorb organic matter in solution especially high molecular compounds.

Ion exchange systems are typical for targeted purifications and are used for softening, heavy metal absorption, and separation between ion species, desalination.

Electrodialysis is also in this category as much as Wet/Thermal Oxidations that "bur" dissolved matter at high temperature and pressure.

Biological systems include all the systems and processes in which the organic matter is reduced by bacteriological activity.

Biological systems are used exclusively for domestic wastewater treatment and whenever possible for the treatment of effluents containing biodegradable organic matter. Aerobic, anaerobic, anoxic versions of bacteria which feed on organic matter, under aerated, non aerated or semi aerated conditions are found at the basis of the various biological treatment systems: aerated and an aerated lagoons, trickling filters, packet and rotating biomasses, up flow sludge blanket, activated sludge, etc. As such, these systems can be included in the targeted purification category.

The main types of biological growths of concern in water environments are: Algae (found in all surface water supplies and differ from bacteria and fungi in that they are able to manufacture their own food. Algae cannot survive in the absence of air, sunlight, or water), Bacteria (these plant forms are universally distributed in nature. They exist in the air currents, in the deep seas, in rivers, streams and soil. Bacteria are unicellular, rod shaped, coccoid or spiral in form.). E.coli, FC, TC, Streptococcus faecalis, Staphylococcus, Salmonella, Clostridium, are some of the known bacteria Viruses: Hepatitis A, Rotavirus, Reovirus, Enterovirus, Bacteriophage, are some of the known viruses.

Protozoa: Giardia,Cryptosporidium, Amoeba, and Balantidium.

Helminths: Ascaris, Trichurius, Ancylostoma, Taenia.

Fungi (These organisms lack the chlorophyll pigment; they exist as parasites deriving their food from living animals or plants, or as saprophytes obtaining their sustenance from non-living materials. Fungi are members of the same plant kingdom as algae and bacteria) As ways of disinfections, one could enumerate the following means: Heat dry or wet, at least at 70 0 C level, is effective in microorganism control.

Complete sterilization achieved can be achieved this way at 1200C.

Gamma Rays create free H and radicals that pass through the cells of the microorganisms, creating damage and death.

U.V. rays are absorbed by the nucleic acids, creating lethal chemical reactions. This radiation has poor penetrating ability and requires special design of disinfection treatment.

pH above 10 leads to the dissolution of the cell external membrane.

Oxidizing Biocides, Chlorine Dioxide (CL02), Ozone Ozone (03), Formaldehyde, Silver, Bromine and Iodineand many other organic and inorganic compounds are used for microorganism control.

Physical devices are also efficient in disinfection, by preventing micro-organisms to continue with the flow (filters) Water recycling has been promoted many years in a passive form called "indirect" or "covert" by using water from a river into which upstream, effluents have been discharged. This is and was the case of many cities of Europe (London, Rotterdam, etc.) and USA.

Indirect or unplanned water recycling for agricultural purposes is also widely practiced throughout the world.

Direct planed wastewater recycling must first answer health risks concerns and then meet other criteria /standards.

Water is used in the industry for process or cooling purposes. Since some industries require very high standards of water (Electronic) it makes sense that such water is being recycled after it has been treated. Superficially industrial recycling is increasing all the time providing savings and opportunities.

There are nine categories of wastewater reuse: Agricultural irrigation (crop irrigation and commercial nurseries) While the use of treated effluent for irrigation purposes depends on many variables related to the effluent, soil, health and safety aspects, etc agricultural reuse today is done for crops that are not eaten raw, especially for "industrial" crops: cotton, wheat.

Landscape Irrigation for lawns and gardens watering a non-direct contact with people application. High standard of bacteriological purity is required.

Industrial reuse (Cooling, boiler process, heavy construction) Usually, about 20% of the fresh water, is drawn by the urban sector that includes industrial mineral and domestic users. The effluents from the urban sector they all end up in the domestic wastewater. From here the importance of recycling for these sectors since it could supply the entire volume of fresh water drawn, without volume limitations.

Ground water recharge (for ground water replenishment, prevention of saltwater intrusion. If it is by natural gravity infiltration it depends on the nature of the soil it passes through. For recharge by injection into the purifier, the wastewater needs to be pre-treated to prevent clogging the injection holes and the contamination of the aquifer.

Recreational and environmental uses (lakes and ponds, marsh enhancement, fisheries, stream flow argumentation.

Non-Potable urban reuse.

Besides watering lawns and gardens, dual distribution systems have been installed in different location in the USA and are used in Hong Kong. The system has not received widespread acceptance. Some other non potable grey water reuses are in fire protection schemes, air conditioning.

Storm water recycling, practiced mainly in the rural areas.

Potable reuse only two locations in the world had intentionate treatment of domestic effluents for potable reuse. One in Windhoek (Namibia) that was planned and installed in 1969 as an integral part of the city water supply system.

The other one Chanute (Kansas, USA) has experienced severe water shortages due to drought conditions.

Since wastewater streams carry high concentrations of pathogenic bacteria, viruses and protozoa as well as a wide variety of organic and inorganic chemicals, which could have both acute and chronic effects on peoples' health, the most injurious failsafe type of treatment technology is required to satisfy and effectively treat wastewater to meet drinking water standards Water reuse is a driving force that dictates the degree of treatment that a particular wastewater treatment plant should deliver. Increased reuse of wastewater has highlighted the need for additional microbiological control At present the wastewater technology is no longer the limiting factor in terms of wastewater reclamation and reuse, the main prohibiting factors being the cost and public perception. A major issue is the risk, actual or perceived that is posed by wastewater to human health and environments The health aspect of the public concern is two fold and on both, the public is relying on regulatory bodies and authorities for receiving the full information based on which, to accept or reject schemes.

The health concerns of the public are to do with: The quality of the recycled or desalinated water for drinking purposes.

The accumulative effect of substances and compounds that, in minute quantities, will go through the elaborate chain of treatment and end up in the drinking water.

Fortunately enough those are also the concerns of regulatory bodies that strive to put in place standards, indicators, online indicators, monitoring and methods to make sure that securing a high standard recycled water is viable, before embarking on the potable recycling scheme It can be concluded that though usable water is a finite resource and shrinking, its demand is growing. This is a life paradox and it points out towards the limitation of this precious resource.

While all water sources are known and most of them are well exploited, some sources have not been considered because of economic and psychological reasons.

Most wastewater treatment processes are tailor designed to meet effluent discharge limits specifications. They all aim for the reduction of the pollutant, disregarding the medium water. This approach led to high uncertainty regarding the best way of solving problems in the wastewater treatment field Recycling of effluents that has already taken off especially in agriculture is desirable as a way of freeing dandling water resources. The most effective way of recycling are the ones for industrial and potable use, which insure the full reuse of the effluent, and do not require special arrangements regarding volumes.

Summary of the Invention There is an acute need for developing a system that will be simple, standard and easy to implement, which could make use of any process or unit operation already employed in the water, wastewater and mineral process domains, and, at the same time provide SA conventional solution to most, if not all the effluent streams, and More usable water from both the known and the ignored sources.

The new integrated system, as described below, has been designed to provide all of the above.

The new system includes a CORE and AUXILIARY parts.

The following steps form the CORE part of the new integrated system: 1. A first Solid Liquid separation-concentration step, that frees the incoming liquid of suspended solids enabling it to pass on and be processed further, while creating a sludge stream that proceeds for processing by usual means.

This first Solid Liquid separation-concentration step, that allows liquid largely free of suspended solids to pass on and be processed further, while enabling sludge processing by usual means, could include any technology, unit operation, or combination thereof, which would achieve the above desired result.

From primary settling tanks, with a 60-65% efficiency of suspended solids separation, currently used in the domestic effluent treatment, through to efficient and fast solid liquid separation devises, like High Efficiency Clarifiers, Dissolved Air Flotation, etc., with a 95-99% efficiency of suspended solids separation, all technologies are acceptable. Yet, only the technologies or combinations thereof that could prove that overall they could provide certain set criteria (as suggested later on), could be considered for integration into the new system.

2. A second Solid Liquid separation-concentration step that separates and concentrates organic dissolved solids from the incoming liquid in a small liquid stream, while rendering a large stream of high quality water.

This second Solid Liquid separation-concentration step that allows liquid free of organic dissolved solids to pass on and be recovered, could include any technology, unit operation, or combination thereof, which would achieve the above desired result.

Those technologies are all from the purification and desalination domains i.e. actuated carbon, foam fractionation, freezing, pressure driven membranes, electrodialysis, and evaporation. Some of those technologies or unit operations might be able to perform part or the entire task of organic dissolved solids separation and concentration, and therefore one, or a combination of a few would be needed to accomplish the desired result.

Yet, only the technologies or combinations thereof that could prove that overall they could provide certain set criteria (as suggested later on), could be considered for integration into the new system.

At this point in time only the pressure driven membranes systems RO, UF, NF) can achieve in average conditions a very high performance 80-95% of the desired task, while at the same time being superior to other technologies in meeting the required criteria.

3. A third step An efficient processing step of the concentrated soluble ingredients (contained in the small stream provided by the previous step), with the appropriate technology/is for their recovery, elimination, or both.

This efficient processing step of the concentrated soluble ingredients (the third step) by the appropriate technology/is for recovery, elimination, or both, could include a wide range of technologies and unit operations from the wastewater treatment, mineral processing, or both.

Technologies as Anaerobic Digestion, Nitrification, MBR (Membrane Bio Reactor), High rate/extended aeration, Wet Oxidation, Pressure Oxidation, Electrolytic Deposition Electrowinning, Catalytic Oxidation, Chemical or Catalytic Reductions, Chemical precipitation, etc., could all be considered.

Yet, only the technologies or combinations thereof that could prove that overall they could provide certain set criteria (as suggested later on), could be considered for integration into the new system.

Considering two types of separated and concentrated ingredients, namely: biodegradable soluble organic matter, and/or soluble metals, only the MBR and the Anaerobic Digestion could make it through the required criteria for the organic matter, while Step Electrowinning could be considered for the dissolved metals recovery, or chemical precipitation for their removal and disposal.

4. A recycling to the main incoming streams, or the disposal of the treated stream from step is the fourth and last step.

After employing the most suitable and efficient technologies in the CORE part of the new integrated system, the stream from step ranging between 10 to 20% of the main stream of recovered high quality water, is still contaminated to some extent, and therefore, it could either be disposed of, pending discharge criteria, or recycled to the main incoming stream.

The introduction of two physical separation/ concentration steps into the system, not only simplifies the whole process of high quality water recovery, but also provides definite and separate steps for processing of liquid and solids within the system, streamlining the system. Additionally, these definite processing paths, enable proper, by the book, high efficiency processing.

These steps form the CORE part of the new integrated system enabling high quality water to be recovered and a water based stream to be efficiently processed.

The above sequence of unit operations makes use of the best approaches and techniques used in water and wastewater treatment as well as in mineral processing operations, while being constant with the best engineering practices concerning processing of low and high concentration ingredients streams.

Auxiliary units Auxiliary units are well-defined unit operations employed in the new Integrated System for specific tasks, and chosen for the integrated system according to the same criteria as those used in choosing unit operations for the CORE processes.

AUXILIARY processes and unit operations could be attached to the CORE part of the system, to facilitate the right conditions for the CORE to operate (pH correction, flocculation, etc.) or to ensure that the quality of the recovered water is suitable for the desired application (chlorination, UV radiation, Ion Exchange, etc.).

Dosing systems for liquid or solid chemicals are widely used to deliver coagulants, flocculants, and chemicals to facilitate the right conditions for the CORE to operate, while Chlorine dosing or UV radiation will certainly be used to make sure that the recovered high quality water from the CORE process is totally free of Pathogens and to enable its safe use.

Preferably, only the technologies, unit operations or combinations thereof that could prove that overall they could provide certain set criteria (as suggested later on), would be considered for integration into the new system as AUXILIARY processes and unit operations.

The key objective of this patent is to provide an integrated system for wastewater treatment and water reclamation that suggests a departure from current approach to the wastewater treatment, by advocating for a shift from pollutant treatment to water recovery and towards a streamlined, synergetic system. This requires a paradigm shift in thinking, but provides a new meaning to the existing technologies and a way of freeing water resources ignored until now, by lowering the costs involved in making them usable.

The philosophy behind this invention has at its base the desire to develop a synergetic, streamlined system that will work on two distinctive and parallel levels, each one intended for a different purpose, i.e. water recovery and impurities treatment respectively), as against the typical and conventional wastewater treatment working at one sequential level.

Brief description of the drawings The invention is illustrated by the attached drawing (Fig.l) that is a schematic flow sheet of the system.

The CORE of the system is contained in the rectangular big box in the center of the drawing, while the AUXILIARIES are designated as two small rectangles, named Aux. and Auxiliaries, to the left and right of the CORE box, respectively.

A wastewater stream shown as the arrow on the top left of the drawing, passes (to the right in the drawing) through screening devises (shown as a crossed circle in the drawing) to remove bulky objects, down to 2-5 mm. in one dimensional size. The wastewater stream, now free of bulky objects, continues (to the right in the drawing) towards the CORE of the system. At this stage, different chemicals, such as Lime, Caustic Soda, Acids, Coagulants, Flocculants, etc., can be added to the wastewater stream by employing AUXILIARY unit operations, such as meter-pumping/dosing to enable a better, more efficient performance of the CORE steps, though as it will be shown further on, this step is not a requirement of the invention, but rather an operational improvement. The addition of chemicals to the wastewater stream at this stage can be identified as the "conditioning" step described previously.

The wastewater stream (with or without additives) enters the first step (an elongated upright oval in the drawing) of the integrated system (up and right in the drawing). As mentioned previously, the first step is a solid/liquid separation/concentration step, during which, two fluid stream are created: one containing the bulk volume of original stream and almost free of suspended, settlable solids and the other one is a small steam in volume but concentrated in suspended solids While the free SS stream/bulk volume proceeds to the second step of the CORE, (straight down in the drawing), the small, concentrated SS stream/slurry exits the CORE (down and to the left in the drawing) to join other streams in conventional sludge treatment.

The bulk of the wastewater stream left after slurry withdrawal, enters the second step of the CORE, which is a second solid/liquid separation/concentration step that enables the separation of dissolved solids (DS) from the liquid carrier and their concentration into a separate, much smaller stream. Pending on the technology employed, this step can contain one or two unit operations designed to work together.

For this reason, the second step of the CORE in the new integrated system is illustrated in the drawing by two small unequal and attached rectangles.

Mainly, two streams are produced in this step: one stream large in volume of water (the arrow to the right leaving the bigger of rectangles of the second step and exiting the CORE in the drawing) containing only small amounts of dissolved solids (DS), and virtually free of biological contaminants, and one small stream, (arrow straight down from the second step to the third step in the drawing) that contains the dissolved solids (DS) and biological contaminants that have been removed from the other (bulk) stream.

The large (bulk) stream of water (arrow to the right leaving the bigger of rectangles of the second step and exiting the CORE in the drawing) is high quality water produced in the new integrated system in two physical type sequential steps, (otherwise achieved in conventional municipal wastewater treatment in three sequential treatments steps: Primary, Secondary and Tertiary two physical/chemical, one of them biological).

This stream is ready for use but is further "disinfected" by employing AUXILIARY unit operations (UV rays or addition of Chlorine or other chemicals with disinfecting properties), though such a step is not a prerequisite of the system, but rather an extra precautionary measure, widely instituted to alleviate public and user concern.

The relatively small stream emerging from the second step and containing the dissolved solids (DS) and biological contaminants that have been removed from the other (bulk) stream (arrow straight down from the second step to the third step in the drawing) proceeds to the third step.

When the second step contains two unit operations working together, the first one is designed to protect and ensure a smooth operation of the second one while the second one produces the separation/concentration effect specific to this step. In such a case, a small stream containing the rest of SS from the previous (first) step (arrow to the left and down from the top and smaller attached rectangle in the drawing) joins the other steams for conventional sludge treatment.

The third step of the CORE (an almost circle oval in the drawing) is a treatment step for the ingredients of the concentrated stream from second step and could include a wide range of technologies and unit operations. As a result of this treatment step the 9 ingredients contained in the stream are either drastically reduced, destroyed, or both, so that the stream could either be disposed of, pending discharge criteria, or recycled to the main incoming stream (the two dotted arrows leaving the third step, one to the left and out of the CORE, and one to the right, and up and left to the first step, inside the CORE in the drawing). Solids (SS) that might result from this treatment will be rutted to the conventional sludge treatment (arrow to the left and up from the third step in the drawing).

The fourth step of the CORE is represented by one of the arrows emerging from the third step to either the right or left: if to the right, the stream emerging from the third step would be recycled to the incoming stream into the first step of the CORE; if to the left, the stream emerging from the third step would be disposed of outside the system. These two alternatives exist to suit the variety of incoming streams treatable by the new integrated system.

Procedure for choosing the most appropriate technologies This procedure refers to a set of conditions or bench marks the system should be able to achieve or comply with so that the qualities, attributes and virtues aimed for or proclaimed, are recognized, appreciated, confirmed and acknowledged, regardless of the specific conditions imposed on the process.

In the spirit of developing an integrated process that will meet the set philosophy and expectations, we have listed the following criteria that the integrated system should meet: a. Wide opportunity spectrum expressed by a high potential that a wide range of technologies could be applied in the new system; i.e. the system should be designed in such a way, that it would accept, include and use technologies on merit, as they evolve from time to time. In other words, significant developments in a certain technology could bring that technology into the new system from not being included previously.

b. simplicity is the quality of not involving complex procedures for operation or maintenance.

c. streamlining or, well defined processing paths for both solids and liquid streams d. high efficiency processing e. standard and modular, meaning not custom built, but rather being readily available and fully replaceable by a similar or more advanced one. It also means being able to be put together in modules or units to suit and perform a definite task within a preset range.

f. environmentally friendly expressed by low footprint and energy requirements g. versatility- the ability to adapt the system to new requirements by changing the type or the number of modules without interfering with system philosophy h. flexibility: the action through which the system is continuously evaluated and its performance upgraded, by employing the most appropriate technologies and unit operations i. Relatively low cost The process of choosing the most appropriate technologies and unit operations is being carried out by screening all potential technologies through a series of criteria 11 that are identical to the points b, c, d, e, f, before including them in the new integrated system.

For a meaningful screening to take place, we have allocated to criteria b,c,d,e,f, values of importance and priority from 1 to 5 in the new Integrated system, the sum of them being 15: b=2, c=l,d=5, e=4,f=3.

While evaluating potential technologies for integration, merit points are given to those technologies, from 1 to 10, on criteria b,c,d,e, and f.

By multiplying the importance value with the merit points for the same criteria, the opportunity value of that option is being obtained. The summary of the five opportunity values constituted the integration value; the higher this value is, the higher the chance of that technology being chosen as part of the new Integrated System.

The following table shows how three theoretical unit operations have been screened for inclusion in the new Integrated System. Following this procedure, new technologies could be assessed, and older but improved technologies could be reassessed for their integration into the Integrated System.

Criteria Importance B 2 C 1 Unit Merit Points 3 4 5 6 7 Total Operation Unit Operation 2 1 Opportunity Merit Opportunity Values Points Values 6 7 14 4 6 6 25 5 25 24 4 16 21 3 9 80 1 70 Unit Operation 3 Merit Opportunity Points Values 5 5 5 5 5

D

E

F

Integration 5 4 3 Value Screening Unit Operations for integration in the new Integrated System, by obtaining Integration Values from merit points given to five criteria for each Unit EXAMPLES OF THE NEW SYSTEM PERFORMANCE IN VARIOUS AREAS OF WASTEWATER TREATMENT AND WATER RECOVERY It has been mentioned before that the integrated system has the potential of being used for the recovery of high quality water from various types of effluents.

Here is a description of the new Integrated System being used in the process of high quality water recovery from three main type effluents emerging from three completely different sources: Municipalities, (Domestic Effluents), and the Metal Finishing Industry.

All tests have been conducted at pilot scale level using real wastewater streams from the relevant sectors.

All tests have been conducted by using: an ordinary Lamella Solid Liquid separator (in the first step of the CORE) for enhanced and effective separation of wastewater streams previously flocculated with suitable polyelectrolytes a Microfiltration/Reverse Osmosis assembly for the second step of the CORE, and a down flow plastic packed-bed anaerobic reactor for the third step of the

CORE.

System performance in the DOMESTIC EFFLUENT TREATMENT Any system for the treatment of domestic effluents, is being designed to remove as much as possible three main ingredients from the incoming wastewater so that the liquid emerging at the end of the system can be discharged without much further treatment into the environment.

The three ingredients are (after screening): Suspended Matter /Solids remaining in the incoming effluent after the removal of bulky objects. The Suspended Solids consist of inorganic matter (mainly Silt) and organic matter in different sizes, from 3 to 5 mm. on the largest side, down to emulsions and colloids, all with different settling characteristics.

Dissolved organic matter consists of different organic compounds dissolved in water.

Measurement of dissolved organic matter is done indirectly, by either measuring the total Carbon (all organic compounds contain Carbon in their molecule), TOC, or by determining the amount of Oxygen required (demanded) to biologically oxidise those organic compounds to Carbon Dioxide CO 2 (BOD Biological Oxygen Demand).

A simpler test, which measures the amount of Oxygen required to chemically oxidise the organic matter to C02, has been developed (COD Chemical Oxygen Demand) In fully biodegradable effluent, the ratio COD/BOD is around 2-3.

Pathogens, are all living creatures arriving with the effluent and including bacteria, viruses, molds, protozoa, and are expressed as Colony Forming Units per 100 mL, or cfu/100mL.

Performance.

In the first step, close to 90% of all Suspended Solids would be separated from the main body of fluid, and concentrated into a 3-4% slurry stream that could then be further processed in a conventional way.

Besides the efficient removal of Suspended Solids (close to this first step in the sequence of newly integrated technologies, also significantly removes Pathogens from the main body of fluid.

Approximately 0.2% of the total body of fluid entering the system as effluent would be lost in this step in the form of slurry, diverted to slurry processing. Most of it would be returned to the system, free of solids, after further processing of the slurry.

In the second step, close to 100% of all Dissolved Organic Matter/Solids are separated, "rejected", concentrated and diverted from the main body of fluid, into a stream 8 to 10 times more concentrated than the original one, stream that could then be further processed in a conventional way.

This step could be achieved by any technology or unit operation designed for that purpose: evaporation, vacuum recompression, pressure driven membranes, freezing, etc.

As a result of this second step, close to 100% of the Dissolved Organic Matter/Solids, is being separated into a stream having a volume of about 20% of the main fluid body.

This step further decreases the amount of Pathogens allowed to pass into the main stream, making the main stream virtually Pathogens free.

In the third step, the concentrated stream containing Dissolved Organics (from the second step) receive special attention. This stream can be treated by a variety of technologies and unit operations pending case by case, on the nature of those concentrated ingredients in the incoming effluent.

The third step of the CORE has been designed as an efficient processing step of the concentrated soluble ingredients and organically bound Ammonium-Nitrogen.

The processing step of the concentrated soluble ingredients and organically bound Ammonium-Nitrogen by the appropriate technology/ies for recovery, elimination, or transformation, could include a wide range of technologies and unit operations from the wastewater treatment, mineral processing, or both.

Technologies as Anaerobic Digestion, MBR (Membrane Bio Reactor), High rate extended aeration, fixed or up-flow Nitrification reactors, Wet Oxidation, Pressure Oxidation, Electrolytic Deposition Electrowinning, Catalytic Oxidation, Chemical or Catalytic Reductions, Chemical precipitation, etc., could all be considered.

For the purpose of this example, the third step includes two biological steps (Fast Aerobic Aerobic reactors)- the most appropriate units operations for the almost complete oxidation of the dissolved organics to CO 2 As a result, 90-95% of the dissolved Organic Matter and any remaining organically bound Nitrogen will be removed from that stream, enabling its recycle to the main incoming effluent stream or discharged into the environment.

Parameter Unit Incoming After First After Second Stream Step Step after (Recovered screening water) Suspended mg/L 200-250 10-25 0 Solids BOD mg/L 200-300 :150-200 0- COD mg/L 400-600 300-400 2-10 TKN mg/L N 50 50 Ammonia mg/L N 40 39 4.4 Phosphorou mg/L P 11 9 0.05

S

Pathogens cfu/lOOmL 3x 9x4i10 5 2xl0 0 (Total count) Faecal cfU/lOOmL Y.lilo 1.3 coliforms Volume 1 unit 1 0.98-0,99 0.8-0.88 TABLE 1: constituents of the main body of fluid /effluent from entering, to exiting the new integrated system Parameter Unit Incoming After First After Second After third stream step step Step (recycled or discharged) Suspended mg/L 200-250 20000 0 Solids BOD mg/L 200-300 150-200 750-2000 100-200 COD mg/L 400-600 300-400 1500-4000 200-400 TKN mg/L N 50 0 222-440 22-50 Ammonia mgIL N 40 16-20 178-3 52 17-35 Phosphorou. mg/L P 11 16-20 j745-90 45-90 Pathogens cfu/lOOmL 3x01 5x1On 7ix10-'T -x 10 6 (Total count) Feacal cfu/lOOmI 5.1xTh" 5x10 9 2x10' 0 20X10 4 coliforms Volume 1 unit 1 0.01 0.1-0.2 0.1-0.

Table 2: constituents of the side streams estimated from the previous table by massbalance.

As it can be seen, in the new integrated system, the main pollutants contaminating the water and rendering it as effluent, namely Suspended Solids, Dissolved Organics, and Pathogens, have been detached, separated and removed from the main body of fluid in the first two (physical) steps of the new Integrated System, releasing a stream which very closely resembles the original water before being polluted...

Nutrients in the form of organic inorganic Nitrogen and Phosphorous compounds, can cause problems of Eutrophication (oxygen depletion) in water bodies (sea, rivers or lakes), if discharged into those water bodies with the secondary or tertiary treated effluents.

Therefore, any system discharging treated effluents into the environment, would encounter the need for nutrients removal.

In the new integrated system, chemicals can be used as an alternative way, besides the treatment means incorporated in the CORE, for the removal of nutrients from the recovered water. Following, are the chemicals and their beneficial addition to the incoming and untreated effluent, towards nutrient removal and improved CORE operability.

Lime addition [CaO or Ca(OH)2] in slurry form to the incoming effluent, so that the pH would rise to a level above would precipitate the Phosphorous as Calcium Phosphate Ca 3

(PO

4 2 form that would be removed together with the raw sludge produced after first and second stages.

would hydrolise and brake the organic compounds, liberating Nitrogen in the form of Ammonium salts, and reduce COD/BOD content of the wastewater would transform the Nitrogen/Ammonium into a readily removable form Ammonia extracted from the system by aeration.

would enable the removal of Nutrients from the system.

would precipitate most of the heavy metals.

It would increase the separation/settling properties of the sludge It would markedly decrease (disinfect) the Pathogen population both in the main body of fluid continuing to the first stage, and in the sludge produced in the first and second stages.

It would protect and improve the operation and separation/concentration efficiency of the first and second stages of the new integrated system.

It would enable the removal of Nutrients from the system in safe and usable forms It would get rid of the odor problem in sewage treatment plants.

Iron salts addition to the incoming effluent stream as high upstream as possible has a multiple effect potential: a- in its Ferrous form (Fe 2 the Iron has the potential of combining and precipitating volatile Sulphourous compounds, preventing them from evaporating and creating smells. Hydrogen Sulphide and other organic sulphourous gases (Merkaptanes), produced in sewers and creating an odor management at the head of works of any sewage treatment plant, are being removed from the liquid phase and precipitated into a solid phase (as FeS) by the Iron This operation has been in use for some time for this purpose.

b- once the pH of the system has risen above 5.5-6 value, excess Iron will quickly oxidise to Iron and either form huge hydrolyzed heavy flocks Fe(OH) 3 which will tend to adsorb on their surface various heavy metals (co precipitation), or c- trap and precipitate all soluble Phosphorous.

d- In all these cases, the formed precipitates would greatly improve the settlability characteristics of the raw/primary sludge.

e- Finally, Iron has a great reducing potential, very useful in preventing oxidants shock loads effects.

Aluminum salts addition, as a way of improving settling characteristics of the sludge or /and removal efficiency of Phosphorous, could also be considered. Together with Lime, Aluminium ions can co precipitate and lower COD and Sulphate concentrations. Though there are fewer advantages in this addition than the Iron salts addition, it offers some independent advantages, pointing out to the use of a mixture of the two salts, as the best way of solving or preventing a range of potential problems.

Though Metal (Iron or Aluminium) salts addition can be made a permanent feature in Waste Water Treatment Plants, Lime addition for achieving a pH level above is incompatible with presently run biological WWTM.

Since this new integrated system is streamlined and does not rely on biological processes for the production of high quality recovered water, the addition of Lime slurry alone can provide a full answer to the Nutrient problem. Additionally, the combined addition of metal salts and lime, can also feature in the new integrated system, providing for the removal of nutrients and pathogens and facilitating a smoother operation of the CORE. (Figure 2) Following are the results of Iron addition and rise of pH to above 10 by Lime addition on the previous results, the configuration of the CORE remaining the same.

Parameter Unit Incoming Iron Lime After First After Second Stream addition Step Step after (Recovered screening water) Suspended Mg/L 200-250 600-700 1-5 0 Solids BOD Mg/L 200-300 100- 150 100-150 5-10 COD Mg/L 400-600 200-300 200-300 5-15 Pathogens Cfu/00mL 3x10 3x10 4 9x10 2 0 PH PH units 5.5-6.5 10-11 8-9 7-8 N Mg/L 40 10-20 10-20 1-3 P Mg/L 11 1 0.5-1 0-0.1 Volume 1 unit 1 1 0.98-0,99 0.8-0.88 Table 3: Constituents of the main body of fluid (domestic effluents) from entering, to exiting the new integrated system, after Lime Iron addition Parameter Unit Incoming After First After After third Stream Step Second Step Step Suspended Mg/L 200-250 40000 1-5 10-20 Solids BOD Mg/L 200-300 100-200 500-1000 20-100 COD Mg/L 400-600 200-400 1000-2000 40-200 Pathogens Cfu/lOOmL 3xlOo 3x1 2 2xl0 3 2x10 PH PH units 5.5-6.5 8-9 8-9 6.5-7 N Mg/L 40 10-20 90-200 10-20 P Mg/L 15 1 0.5 Volume 1 unit 1 0.01 0.1-0.2 0.1-0.2 Table 4: Constituents of the side streams generated in the new Integrated System after Iron Lime addition Implementation in the METAL FINISHING INDUSTRY Though the Metal Finishing Industry is very diversified to accommodate specific needs for metal plating, surface treatment, and coating, a general type of effluent emerging from this industry would contain various concentrations of ions, the Heavy Metals, Chromates and Cyanides being the ones of concern. No Pathogens are present in those effluents.

Conventional treatment practiced in the Metal Finishing Industry, treats in parallel two or three streams: One containing Cyanides, is being oxidised at a pH higher than A second stream containing Chromates (Cr and Heavy Metals is being "reduced" at a pH lower than Sometimes the stream containing Chromates is kept separate from the one containing Heavy Metals, the former producing a third stream.

All streams are combined after their individual treatment, and the pH is adjusted to 8- 9. As a result, all Heavy Metals are being precipitated as Hydroxides and separated from the main body of the fluid that is being discharged to sewer.

The treatment process is complex, require a lot of monitoring and control, and in most cases does not offer any water saving The implementation of the new Integrated System in the Metal Finishing Industry is straightforward.

Dosing Iron upstream and in enough amounts, would convert both the Chromates [containing Chromium ion] and the Cyanides into compounds and/or complexes available for separation and removal straight away or after further processing.

Chromates would be reduced to the Chromium compound easily and efficiently precipitated at pH levels above 8, while the Cyanides will be captured in the highly stable complex Fe 3 [Fe (CN) 6] 3 which is insoluble below pH level of Lime addition is required to achieve the pH level of 8.3. At this pH, most of the Heavy Metals (including Chromium) will be removed in the first solid/ liquid separation and concentration step of the CORE. Most of the precipitated compounds will be in the hydroxide form (all heavy metals) while the cyanide will be separated in its Iron complex form. Phosphates present will be removed in the form of Calcium Phosphate.

After CORE first step, the solution almost free of Heavy Metals, Cyanides, Chromates and Phosphates (hydroxides Suspended Solids), will undergo a liquid separation/concentration process provided by CORE second step in the new integrated system. Up to 90% of the processed effluent is then produced in the form of high quality water, suitable for immediate use as rinse water in the same industry that produces the effluents.

19 The concentrated side stream emerging from the liquid concentration step, the second in the CORE, will have to be processed in a Physico-chemical adsorption and/or oxidation unit for further purification or oxidation. This step is being usually omitted, the small stream being added to the ordinary sewage where it is being diluted and becoming insignificant.

Parameter Unit Suspended mg/L Solids Heavy mg/L Metals Chromates mg/L (Cr+6) Free mg/L Cyanides Volume 1 unit Incoming stream 500-600 After After First After Second Iron(2) and step Step Lime (Recovered addition _I water) 900-1000 1-5 0-1 200-300 200-300 0.5 400-600 0 0 0 300 0 0 0 1 1 0.98-0.99 0.8-0.88 ppH H units 5.5-6.5 8.3 8 8 Chromium Phosphates mgIL O 300 10.3-06 102-0l4 mg/L 35 35 0.5-1 0.1-0.5 Table 5: Recovery of high quality water from a general effluent produced by the Metal Finishing Industry It can be seen, that the new integrated system could be easily implemented and used for the recovery of high quality water from an effluent emerging from an industry that has the potential of discharging dangerous polluting ingredients. In the process of high quality water recovery, the new process uses the original design, philosophy and principals. All attributes and virtues assigned to the system from the beginning are valid here.

In this specific case, the system has simplified the processing procedure, enabling treatment of one combined stream of effluents, instead of three, lowering the capital cost of the treatment by at least recovering at least 75% of the combined volume of effluents as high quality water lowering the water consumption in the production plant by the recovered amount.

reducing the amount and variety of chemicals needed for efficient effluent treatment Increasing the potential of implementation for the new integrated system in the Metal Finishing Industry, by providing an economically desired recovery system instead of an "end of pipe treatment".

Implementation in the FOOD INDUSTRIES (DAIRY AND SLAUGHTERHOSES).

Food Industries use huge amounts of water during processing.

Because of high concentrations of biodegradable compounds accompanied by high concentrations of suspended solids, oil and fat they contain can constitute a huge organic load on sewage treatment plants receiving these effluents.

This load that has been paid in the past by the industry both as a consumption load, and as an extra discharge load, proved to be unacceptably high for sewage treatment plants receiving such effluents.

Therefore, effluents emerging from dairy industry and slaughterhouses require some kind of pre-treatment to remove the bulk of suspended solids, oil and fat they contain, before being discharged to sewer.

Over the years, it has been found that the removal of Suspended Solids carried out at conditions of pH range 4.6-5.2, could achieve not only a high rate of SS removal, but also the removal of a certain degree of dissolved organic matter.

This way, by employing compact and efficient devices for solid liquid separation, dairies, slaughter houses, and other food industries have geared up for an in-house treatment that can render a treated effluent of a quality similar to that of the ordinary domestic wastewater. By doing this, the food industry no longer puts an extra organic load (estimated to thousands of other than the hydraulic one.

The implementation of the Integrated System in the food industry would certainly save the industry from extra payments, and the water resources from extra exploitation.

Tables 6 and 7 show the possible results of such implementation.

Parameter Unit Incoming Iron and After First After Second Stream addition to Step Step increase pH (Recovered water Suspended mg/L 1500-1600 1900-2000 10-50 0-1 Solids COD mg/L 2000 2000 600 10-20 Volume 1 unit 1 1 0.98-0,99 0.8-0.88 pH PHunits 5.5-6.5 10-11 8 8 Table 6: constituents of the main body of fluid from entering, to exiting the new integrated system Parameter Unit Incoming Side stream Stream After First Step Side stream After Second Step After third Step Suspended Solids

COD

Volume pH mg/L mg/L 1500- 1600 400-600 1 unit 1 PH units 5.5-6.5 80000 1-5 10-20 600 6000 600 0.01 0.1-0.2 0.1-0.2 8-9 7-8 6.5-7 Table 7: Constituents of the side streams in the new integrated system SYSTEM ALGORITHM In order to facilitate a speedy adaptation of the process to various types of effluents the system might be called upon to recover water from and deal with their pollutants, it has been found useful to produce a general Algorithm of all essential steps that are to be included in the new system according to the characteristics of the wastewater.

Such an Algorithm could help remembering all the essential steps that may or maynot be included in any particular design, and analysing important ingredients that in a later stage might prove to be an important parameters in the design.

A third and not less important aspect in which the Algorithm can help is the prevention of operating problems in different unit operations included in the system.

A typical example is the presence of Sulphate ion (S04) in relatively high concentrations in the wastewater. Such a concentration could cause severe scaling problems ifRO or NF is being used or considered for use. Similarly, high concentrations of Sulphate could lead to the production of high concentrations of Hydrogen Sulphide (H2S) in the Fast Anaerobic Digester (FAD) that could hinder its operation.

Hydrogen Sulphide is also being produced "naturally" in sewers following anaerobic activity and long retention time of sewage in close, non-aerated pipes. This creates an aesthetical-environmental-management problem, everybody is keen to solve or even better, prevent.

The following Algorithm is meant to help deciding the most appropriate actions to be taken regarding steps 2 and 3 belonging to the CORE, and regarding types of chemicals to be considered for dosing.

Claims (12)

1. A system that has been specifically designed to minimise the steps in which high quality water can be made available, and to maximise the processing efficiency of the dissolved polluting ingredient by providing a synergetic, streamlined system that will work on two distinctive and parallel levels, each one intended for a different purpose, water recovery and impurities treatment respectively), and contains a CORE treatment, made of at least two steps of solid/liquid separation which on its own can deliver high quality water, to which, specific secondary modules can be attached, to enable the system to perform better, tackle unusual or specific wastewaters, or comply with specific water quality targets

2. A system as described in claim 1, that consists a CORE treatment, including at least two steps of solid/liquid separation, and can provide high quality water without the use of a biological treatment step and contains at least two physical barriers to prevent bacteriological contamination of the high quality water.

3. A system as the one described in the previous claims, containing one of the following assemblies in the CORE: Ultrafiltration/Reverse Osmosis, Ultrafiltration/Nanofiltration, Microfiltration/Nanofiltration, Microfiltration/Ultrafiltration, Ultrafiltration/Ultrafiltration, Microfiltration/Reverse Osmosis

4. A system as described in claim 1 that is fully modular and standard and could be employed for any size wastewater treatment project without the need of elaborate infrastructure, and power resources.

5. A system as described in claim 1, that constitutes a tool for solving environmental problems by having the running costs lowered, reducing the demand on fresh water resources, opening the way of using water resources ignored until now, ameliorating water shortages, and solving salinity problems and producing water ready for consumption in remote or small locations, without the need of elaborate infrastructure, and power resources while combined with natural sources of energy (wind, solar power and power cells) or Methane generated power

6. A system as described in claim 1, that "passes" the test of sustainability for having an integrated approach, being parallel not sequential, and seeking net benefits without trade offs.

7. A system as described in claim 1 that enables treatment of one combined stream of effluents in the Metal Finishing Industry, instead of three.

8. A system as the one described in the previous claims, that contains three barriers to prevent bacteriological contamination of the high quality water: at least two physical barriers contained in the CORE, and one chemical, by rising the pH of the wastewater stream entering the first step of the CORE, to a value in the range of 10-12.

9. A system as the one described in the previous claims, that uses a set of criteria to choose the most appropriate technologies for integration and to ensure that the new system will always remain the preferred system for wastewater treatment and recovery of high quality water.

A system as the one described in the previous claims, containing biological treatment unit/s (AEROBIC, ANAEROBIC or both) in the CORE for the effective treatment of concentrated biodegradable organic ingredients as well as Nitrogen removal purposes

11. A system as the one described in the previous claims, containing (a) PHYSICO-CHEMICAL treatment unit/s in the CORE for the effective treatment of concentrated inorganic ingredients as well as Nitrogen removal purposes.

12. A system as the one described in the previous claims, containing PHYSICO- CHEMICAL treatment unit/s together with biological treatment unit/s (AEROBIC, ANAEROBIC or both) in the CORE for the effective treatment of concentrated inorganic, non-biodegradable and biodegradable organic ingredients as well as Nitrogen removal purposes. RAUL RAITER 10 SEPTEMBER 2003