Global Water Pathogen Project Part Four Management Of-Free PDF

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Copyright , This publication is available in Open Access under the Attribution ShareAlike 3 0 IGO CC BY SA 3 0 IGO . license http creativecommons org licenses by sa 3 0 igo By using the content of this publication the users. accept to be bound by the terms of use of the UNESCO Open Access Repository. http www unesco org openaccess terms use ccbysa en . Disclaimer , The designations employed and the presentation of material throughout this publication do not imply the. expression of any opinion whatsoever on the part of UNESCO concerning the legal status of any country . territory city or area or of its authorities or concerning the delimitation of its frontiers or boundaries The. ideas and opinions expressed in this publication are those of the authors they are not necessarily those of. UNESCO and do not commit the Organization ,Citation . Verbyla M von Sperling M Maiga Y 2017 Waste Stabilization Ponds In J B Rose and B Jim nez . Cisneros eds Global Water Pathogens Project http www waterpathogens org C Haas J Mihelcic and M . Verbyla eds Part 4 Management Of Risk from Excreta nad. Wastewater http www waterpathogens org book waste stabilization ponds Michigan State University E . Lansing MI UNESCO , Acknowledgements K R L Young Project Design editor Website Design. http www agroknow com , Published March 13 2017 1 12 pm Updated September 20 2017 1 50 pm.
Waste Stabilization Ponds, energy inputs ,Summary. Waste stabilization ponds WSPs are sanitation Waste Stabilization Ponds. technologies that consist of open basins that use natural. processes to treat domestic wastewater septage and 1 0 Brief Technology Description. sludge as well as animal or industrial wastes They can be. used in centralized or semi centralized sewerage systems Waste stabilization ponds WSPs are open basins. they can also be used to treat fecal sludge from onsite dry enclosed by earthen embankments and sometimes fully or. sanitation systems or as onsite water based sanitation partially lined with concrete or synthetic geofabrics They. systems serving a single building or home The most employ natural processes to treat domestic wastewater . common types of WSPs are anaerobic ponds facultative septage and sludge as well as animal or industrial wastes . ponds maturation or polishing ponds aerated ponds and They can be used in centralized or semi centralized. high rate algal ponds HRAPs Some pathogen removal is sewerage systems serving cities or towns they can also be. accomplished in anaerobic facultative aerated ponds and used as onsite systems serving a single entity e g highway. HRAPs even though their primary function is to remove rest area community center etc Figure 1 WSPs are. and stabilize organic matter The primary function of frequently used in combination with other sanitation. maturation and polishing ponds however is to remove and technologies The most common types of WSPs are. inactivate pathogens Under optimal conditions removal anaerobic ponds facultative ponds maturation ponds . efficiencies in full scale WSP systems with several units in aerated ponds and high rate algal ponds HRAPs These. series can be as high as 6 log10 for fecal bacteria and 4 log10 ponds differ in terms of their function in the overall. for viruses protozoan oo cysts and helminth eggs wastewater treatment system The main function of. however the efficiency of pathogen removal in full scale anaerobic facultative and aerated ponds is the removal of. systems is highly variable and in practice many WSP carbon containing organic matter while the main function. systems achieve only 2 to 3 log10 removal Some of the most of maturation ponds is the removal of pathogens HRAPs. important factors influencing pathogen removal efficiency were developed to optimize the efficiency of organic matter. in WSPs include hydraulic retention time and efficiency removal while simultaneously allowing for the recovery of. water clarity pond depth sunlight exposure and dissolved nutrients that become incorporated into the algal. penetration temperature and pH Shallow 1m baffled biomass These different pond types are distinguished from. maturation ponds with low turbidity high pH and plenty of each other by their depth hydraulic and organic loading. sunlight exposure will achieve the most efficient pathogen rates and by whether or not they use mechanized. reduction The sludge sediments from WSPs especially equipment for mixing or aeration In general anaerobic. anaerobic facultative and aerated ponds must be removed ponds are deepest 3 0 m and are used first in series . periodically and treated or managed appropriately to limit facultative ponds are shallower 1 5 3 0 m and may be. human exposure The concentration of viable helminth eggs used first or second in series after anaerobic ponds . and protozoan oo cysts in this sludge can be as high as maturation ponds are shallowest 1 5 m and are used. 2 000 4 000 per gram of total soilds and helminth eggs in last in series Aerated ponds may be used anywhere in a. particular can survive in WSP sediments for years WSP series of ponds and HRAPs are often used in by themselves. sysetms require large areas of open land making them or between anaerobic and maturation ponds For more. ideal in smaller towns and rural settings though they are information about the design of WSP systems refer to von. used successfully in many urban environments as well Sperling 2007 Oakley 2005 Shilton 2006 or Mara. often in combination with other sanitation technologies 2003 Figure 2 illustrates different types of ponds and one. One of the biggest advantages of WSPs is that they are easy schematic of a typical WSP system design with three. and inexpensive to operate and maintain and generally do different types of ponds anaerobic facultative and. not rely on mechanized equipment or expensive material or maturation operating in series . 3, Waste Stabilization Ponds, Figure 1 Waste stabilization ponds are a centralized or semi centralized treatment technology in the overall. sanitation service chain used with sewered sanitation systems and also to treat the contents of onsite systems. 4, Waste Stabilization Ponds, Figure 2 Schematic of a typical waste stabilization pond system top anaerobic pond in Brazil middle left photo. from Stewart Oakley facultative pond in the United States middle right photo from Matthew Verbyla maturation. pond in Bolivia bottom left photo from Matthew Verbyla high rate algal pond in Burkina Faso bottom right photo. from Ynoussa Maiga , 2 0 Inputs and Outputs for Waste Stabilization The outputs from WSP systems include the treated. effluent liquid sludge sediments solids and biogas The. Ponds, treated liquid effluent from WSPs is often continuously.
discharged however operators of some systems especially. WSPs can be used to treat a variety of water and waste. in colder climates may stop discharging for months at a. streams thus the inputs may include wastewater septage . time allowing the ponds to fill up and discharging once the. latrine pit contents and or sludge from other wastewater. temperature gets warmer this extra retention time makes. treatment processes Figure 3 Some WSP systems also. up for the slower rate of treatment during colder months . receive landfill leachate WSPs may receive untreated Sludge accumulates over time at the bottom of WSPs and. wastewater that has gone through preliminary treatment must be removed every few years anaerobic ponds every. e g screening and grit removal or they may receive decade primary facultative ponds or every few decades. secondary effluent from some other treatment process secondary facultative or maturation ponds Sludge. such as anaerobic reactors activated sludge or trickling removed from WSPs is contaminated with pathogens and. filters Typical concentrations for pathogens in wastewater needs to be safely managed to prevent exposure or. septage latrine pit contents and or sludge are provided in treated to reduce the concentration of pathogens Refer to. Part Three of GWPP the chapter on Sludge Management . Figure 3 Typical inputs and outputs from waste stabilization pond systems. 3 0 Factors Affecting Pathogens in Waste though sedimentation is perhaps the most important . Helminth eggs are primarily removed by sedimentation . Stabilization Ponds, and other factors are less important Different pathogen. types that are removed by the same mechanism are not. Different factors affect different types of pathogens in. necessarily removed at the same rate by that mechanism . different ways The most important factor for the removal. For example viruses and bacteria are both damaged by. of viral and bacterial pathogens is sunlight exposure sunlight in WSPs but viruses are generally more resistant. although other factors such as temperature dissolved than bacteria Davies Colley et al 2005b Sinton et al . oxygen and pH are also important Sedimentation 2002 Different species of viruses and bacteria are also. hydraulic efficiency sunlight exposure and physical removed at different rates in WSPs due to differences in. chemical factors including temperature and pH are all their structural and genetic composition Silverman et al . important factors for the removal of protozoan pathogens 2013 Mattle et al 2014 Kohn et al 2016 . 5, Waste Stabilization Ponds, Figure 4 Major factors affecting pathogen removal in waste stabilization ponds and causal loop diagram showing the. influence of sunlight on pathogen die off, 3 1 Sunlight and Water Clarity suspended growth algae which contribute to the turbidity. of the water Jasper et al 2013 Silverman et al 2015 . The UV portion of sunlight directly damages pathogen found no pathogen removal benefits to making maturation. genomes photobiological damage while UV and visible ponds any deeper than 50 cm . wavelengths can react with photosensitizers in WSPs such. as natural organic matter or photosensitizer molecules Sunlight is one of the most important factors for viral. within bacteria such as NADH NADPH flavins and and bacterial pathogen removal in WSPs E coli loses. porphyrins to produce reactive species that indirectly viability almost 20 times faster in WSPs with sunlight. damage pathogens photo oxidative damage Sunlight is exposure compared to dark conditions and it is also. stronger at lower latitudes higher elevations and in inactivated faster in shallower WSPs Maiga et al 2009a . locations with less cloud cover The composition of WSP Campylobacter jejuni is more vulnerable to sunlight. water is also important sunlight is rapidly attenuated damage than Salmonella enterica which is more vulnerable. within the first few centimeters of WSPs Davies Colley et than E coli Sinton et al 2007 Enterococci and E coli are. al 2005a Research has demonstrated a clear relationship equally as vulnerable to sunlight in clear water Kadir and. between the amount of direct sunlight that reaches Nelson 2014 Maraccini et al 2016 Silverman et al . pathogens and their rate of inactivation Nguyen et al 2016 but enterococci were inactivated more rapidly than. 2015 Silverman et al 2015 Dias 2016 Thus the clarity E coli in a WSP in Ouagadougou Burkina Faso Maiga et. of water in WSPs and the amount of sunlight penetration is al 2009b perhaps due to their greater vulnerability to. a very important factor Sunlight penetration can be sunlight in the presence of external photosensitizer. improved in maturation ponds by designing them to be molecules that may be present in WSPs with high. shallower than 1 m a depth that is the current standard concentrations of organic suspended solids Kadir and. maturation ponds can be as shallow as 20 40 cm Maiga Nelson 2014 Bacteria can repair sunlight damage in the. et al 2009a Jasper et al 2013 as long as a liner is used dark Oguma et al 2001 while viruses cannot however a. to prevent the growth of emergent vegetation This is few viruses may be able to repair sunlight induced damage. especially true if the pond allows for the growth of after initiating an infection by utilizing their host cell s. periphyton which grow at the bottom instead of DNA repair machinery Weitzman et al 2004 . 6, Waste Stabilization Ponds, Protozoan oo cysts are much more likely to be removed 3 3 Physical Chemical and Microbiological. in a WSP system due to sedimentation than sunlight but Factors. they are susceptible to sunlight damage viable, Cryptosporidium parvum oocysts were reduced by 0 2 log10 The most important physical chemical factors for.
units in WSP water after four days of sunlight exposure pathogen inactivation are pH temperature and dissolved. Reinoso and B cares 2008 C parvum is capable of oxygen in the presence of dissolved organic matter Most. repairing sunlight damage however it does not necessarily bacterial pathogens are vulnerable to high pH with Vibrio. regain infectivity Oguma et al 2001 Regarding spp as a notable exception Mezrioui et al 1995 The. helminths Ascaris eggs have high resistance to solar sanitizing effect of free ammonia which becomes more. disinfection Bandala et al 2012 Heaselgrave and available at higher pH is even more effective at higher. Kilvington 2011 Thus sunlight exposure is not likely an temperatures Decrey et al 2014 Emmoth et al 2011 . important factor for the removal of helminth eggs in WSPs Burge et al 1983 Helminth eggs are the most resistant to. physical chemical factors in WSPs they can survive for. Waste Stabilization Ponds 4 Figure 1 Waste stabilization ponds are a centralized or semi centralized treatment technology in the overall sanitation service chain used with sewered sanitation systems and also to treat the contents of onsite systems

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