EXECUTIVE SUMMARY AND TECHNICAL INFORMATION

Transcription

1 Background EXECUTIVE SUMMARY AND TECHNICAL INFORMATION A new technological solution, the Manz Slow Sand Filter, by Oasis Filter International Ltd. provides the opportunity to meet future water production demand in a sustainable, cost-effective and environmentally responsible manner. The Manz Slow Sand Filter, patent pending, is the outcome of a water engineer s passion to expand access to clean water. Dr. David Manz, the inventor and 50% owner in Oasis, is an internationally renowned expert in water and wastewater treatment. The Manz Slow Sand Filter ( MSF ) has applications of 240 to 15,000,000 litres (60 to 4,000,000 gallons) per hour in all markets (developing, emerging and developed countries). Technical Novelty The Manz Slow Sand Filter distinguishes itself from competitive systems through its primary benefits: Offers a much wider range of pathogen, particulate and toxin removal than any other traditional sand filtration technology Process results in a significant reduction of waste water Minimizes the need to use chemicals Cost effective operation not requiring highly skilled operators which allows community maintenance and operation May be manufactured using the most cost-effective local material whether precast or poured in place concrete, steel, aluminum, fibreglass or plastic Smaller systems may be operated manually or with minimal energy sources such as solar power May be skid mounted for transportation to remote areas and for rapid use in emergency relief (500 to 10,000 litres per hour) Larger systems provide a range of automation from minimal to completely automated Does not require economies of scale to be a cost effective water treatment solution yet it is also competitive in larger scale project applications Superior polishing filtration characteristics Most appropriate technology available to remove arsenic for small to large communities.

2 2 Although the MSF technology began its formal patent applications in 2006, it is a mature technology since the novelty is primarily achieved by combining the best attributes of a number of well established technologies utilizing the strengths and shedding the weaknesses. Specifically, the Manz Slow Sand Filter is unique as the first sand filter to introduce cleaning by fluidizing only the top two layers under low pressure. The ease of cleaning in comparison to traditional slow sand filters, in turn, provides greater scope in the range of quality of water that may be treated. This allows it to be used in a much wider range of applications such that the filtration system can be used for more than just pathogen removal. This innovation allows the MSF, alone or in combination with other technologies, to be very effective in the removal of pathogens (parasites, bacteria, and viruses), particulate (silt, clay, and organics), iron (and iron bacteria) and manganese, arsenic and fluoride, dissolved organics, sulphur smell and other obnoxious gases, colour, foul taste, toxins and algae. All the manufacture, materials and the construction of the Manz Slow Sand Filter are sourced in-country. Whereas, due to the complexity of most competitive systems, components are imported into the country with significant ongoing maintenance and operation support required from the water treatment equipment supplier. Since the MSF is conducive to allowing construction of any size plant with community maintenance and operation, its attributes are more in tune with the aspirations and requirements of most smaller local markets. The simpler design of the MSF combined with ease of operation creates an environmentally efficient, more reliable and certain safe water supply, with fewer breakdowns, less use of chemicals, and less waste water. The MSF can treat surface water and groundwater. Due to its ease of cleaning, it may also be used as a polishing filter to pre-treat saline water, wastewater pre-treated to secondary standards, grey water, storm water runoff, and industrial and agricultural water and wastewater. Appendix I Unique Market Opportunities describes the various potential applications of the MSF. To enable a proper technical evaluation Appendix II-A provides a table comparing the capability of the Manz Slow Sand Filter to traditional sand filters. Appendix II-B provides Comparison of the MSF to Traditional Sand Filter Systems which is a detailed description. Appendix III and IV provide an indication of the potential role of the MSF in actual examples of difficult to treat surface and ground water situations respectively. California, in particular, has a significant problem of arsenic in drinking water which smaller communities have difficulty in addressing. More than 13 million people in the United States routinely obtain water from public sources that are above the maximum contaminate level for arsenic. This is a treatment segment where Oasis could have a dominant position due to a number of relative advantages including an ability through using the MSF to completely eliminate the arsenic laden waste water disposal problem. There are many countries in the world where arsenic prone drinking water has been detected at a concentration greater than the Guideline Value, 0.01 mg/l or the prevailing national standard; Argentina, Australia, Bangladesh, Cambodia, Chile, China, Hungary, India, Laos, Mexico, Myanmar, Nepal, Pakistan, Peru, Slovak Republic, Taiwan, Thailand, the United States and Vietnam have a very significant portion of their population affected.

3 3 Appendix V provides a table comparing the MSF to current arsenic removal technologies. This table is intended to highlight the advantages of the MSF as an alternative and to illustrate the difficulties encountered by smaller communities in sourcing an appropriate technology. The nine competitive technologies as set out in Appendix V each have impediments: many require media regeneration chemicals which are very expensive; problems associated with handling hazardous waste; the technologies may generate large quantities of waste; or, many are able to only handle limited water quality conditions or require a number of chemical adjustments to precondition various water qualities encountered before treating. In general the other technologies are complex treatment technologies requiring a significant capital investment with high operating costs. Most importantly, due to these impediments the systems are more at risk to periods of interruption of service for a myriad of reasons. David Manz is the inventor of both the MSF and the BioSand water filter technology. David Manz, Ph.D., P.Eng., P.Ag. brings over twenty five years consulting experience in water related industries of private and publicly owned water and wastewater treatment firms. In the late 80 s, he invested and developed the BioSand water filter. This filter has achieved worldwide humanitarian success as a household filter, and in 1996, earned a Project Achievement Award from the Association of Professional Engineers, Geologists and Geophysicists of Alberta. It is unprecedented for an individual engineer to be recognized with this award. In 2009 David Manz won the prestigious Emerald Award as the winner of the Individual Commitment award category. He also currently instructs part time in the evenings at the University of Calgary on water management, global warming and climate change and water and wastewater treatment for small communities. David Manz has published numerous papers in journals and conference proceedings. David Manz Curriculum Vitae is provided in Appendix VI. Comparison of the MSF to Traditional Sand Filter Systems In summary the main distinction between the Manz Slow Sand Filter (MSF) and traditional sand filters is in terms of having greater application: Slow sand filters are generally used only to remove pathogens and very little particulate matter because the maintenance cycle is relatively difficult and time consuming since it requires manual scraping which renders the filter system inoperative during cleaning. If it were used for the other removal processes which may generate additional waste material it would tend to cause the slow sand filter to require too great a frequency of maintenance. Rapid and pressure filters are primarily used to remove particulate and possibly parasites if used in combination with significant pre-treatment. Alone, they are not effective in removing bacteria, viruses and parasites. Alternative systems used for arsenic removal may require pre- and post-treatment ph adjustment, larger volumes of solid waste are generated, the treatment technology is significantly more complex with a high operator skill level required; none of which occur using the Manz Slow Sand Filter or BioSand Filter which also have a greater arsenic removal efficiency.

4 4 The MSF is simple to operate and to clean, it has a low operating cost and produces very little waste water. The slow sand filters are also simple to operate and produce little waste water but are not easy to clean since they require manual scraping. The rapid and pressure sand filters require a vigorous backwash usually automatically initiated with the captured material filtered to wastewater. The MSF method of cleaning is a limited backwash of the surface layer which may be initiated automatically or manually. The rapid and pressure sand filters are complex to operate: they require a skilled operator; have higher operating costs; and, produce large volumes of waste water. The MSF and the slow sand filter are simple to operate and may not require chemicals to achieve system performance. Breakthrough is not possible with the MSF or slow sand filter whereas breakthrough indicates cleaning is required in the case of the rapid and pressure sand filters. The MSF and slow sand filters have low construction costs whereas rapid and pressure sand filter costs are high. MSF and slow sand filters are used from household (BioSand Filters ) to community scale, rapid sand filters for large scale and pressure sand filters for small community scale. The MSF and BioSand water filters are also much simpler to construct than traditional sand filters. Some of the main design characteristics of the MSF are as follows: The MSF uses a unique filter bed with the same or better filtration characteristics of that used in traditional slow sand filtration. The MSF is cleaned by fluidizing the surface of the media bed and eliminating resulting wastewater. This is achieved by employing a media bed that performs as those used in slow sand filters and incorporating an underdrain and backwash system similar to that used in pressure filters. The backwash of a MSF is only intended to break up the upper layers (where virtually all of the waste material is collected) and re-suspend captured material which is unlike the backwash process used by rapid sand filters or pressure sand filters, where the backwash process must not only fluidize the bed; but, must also permit the scouring and flushing of captured material from well within the filter bed itself. The backwash of a rapid sand or pressure sand filter must be long enough to ensure that all of the captured particles have been flushed from within the media. MSF s underdrain system closely resembles that used in pressure sand filters but it is not nearly as extensive since MSF must only fluidize the upper layers for a short period of time to effectively remove and suspend captured particulate material in the backwash water. The flow of filtered water is controlled using a weir-type outlet system (outlet standpipe) connected directly to the filter underdrain system similar to that used with traditional slow sand filters. During normal operation the flow of water into the filter and the maximum depth of water over the filter bed are established by mechanical float valves attached to the raw water inlet pipes within the filter itself. The flow of water into the filter cannot exceed its production. The combination of the permissible maximum head on the filter bed and restricted flow rate eliminates the risk of

5 5 compaction of the top layer of the media bed. The erosive power of untreated water entering the top of the filter is eliminated as the water enters the filter. Once it is determined that filter production is unacceptably low, filter production is isolated and backwash water is allowed into the underdrain system. Treated water is used for backwashing. The backwash of a MSF is intended to break up the upper layers only (where virtually all of the material is collected) and resuspend captured material. The wastewater produced during the backwash process is removed using perforated pipes located along and attached to the interior walls of the filter. The perforated pipes are attached to a siphon spillway system that also acts as an emergency overflow system. The entire filtration plant is divided into equal segments that can be cleaned independently and successfully using lower capacity distribution pumps and produce flow rates and volumes of wastewater that can be economically evacuated and disposed of. The MSF may be put into production immediately after cleaning without any need for filter to waste. The media bed used in a MSF consists of at least five layers (depending on scale of filter) of differently sized crushed quartzite (silica) each meeting the material characteristics required for slow, rapid or pressure sand filters as stated by the American Water Works Association (AWWA). The upper two layers or filtering layers use uniform graded media that meet or exceed the specifications for slow sand filtration. The top layer provides most of the filtering action. The bottom three layers of the media bed or underdrain allow uniform vertical flow, downward and upward, through the filtering layers while filtration is in progress and even distribution of the water across the entire bottom of the filter bed during a backwash. The depth of the underdrain may vary with filter capacity while the depth of the filtering layers is constant.