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PDF Wastewater Stabilization Ponds (WSP) for Wastewater Treatment - EOLSS Answer: Introduction Communication is a process that helps to transfer information and knowledge as well as it helps to build up understanding between two or more peoples. 20 0 obj Ecosan. Design manual for designers, builders and operators on the design and operation of artificially constructed wetlands and waste stabilization ponds. to, Advantages and disadvantages of stabilization pond treatment process, Fluid, Electrolyte, and Acid-base Balance, Longmen Town, Lintao County, Gansu Province, launched a large-scale investigation and major renovation of the starch processing industry, The Market Supervision Office of Longmen Town, Lintao County, Gansu Province, carried out a special inspection of food safety before the "Double Festival", Benxi biological hepatitis B and AIDS test box have been registered. What is cereal alcohol? If the design or operation management is not in place, it will cause secondary pollution . However, expert design is still required (see also developing human resources). It should be fully compacted and as flat as possible, and the completed height difference of the pond bottom shall not exceed 0. endobj endobj plum healthcare group . This manual has been prepared as a tool to help improve DFID's (Department for International Developments, United Kingdom) support for water supply and sanitation projects and programmes in developing countries. They are very effective at removing disease-causing organisms (pathogens) from wastewater. The major disadvantages of WSPs are a rather long process of days to week (MARA & PEARSON 1998;ROSE 1999) and requirement of large areas of land far away from homes and public spaces for the construction (DEPARTMENT FOR INTERNATIONAL DEVELOPMENT1998). FPs loose ammonia into the air at high pH; and settle some nitrogen and phosphorus in the sludge. 10 0 obj Fecal coliform bacteria removal mechanisms, the effect of parameters such as temperature, pH, dissolved oxygen, organic loading, solar radiation on removal efficiency is investigated. To protect the pond from runoff and erosion, a protective berm should be constructed around the pond using the excavated material. N and P) and is therefore appropriate for the reuse in agriculture , but not for direct recharge in surface waters. There are three types of ponds, (1) anaerobic, (2) facultative and (3) aerobic (maturation), each with different treatment and design characteristics. The oxygenation of the aeration pond is the same as other aerobic processes . 8) What is the most common type of pond in use today? PEARSON, H. If used in combination with algae and/or fish harvesting (see Fish Pond), this type of pond is effective at removing the majority of nitrogen and phosphorus from the effluent. They are semi-centralised treatment systems combined after wastewater has been collected from toilets (see also wastewater collectionand user interface). catalina chicken recipe apricot jam Anasayfa; wright county, iowa police reports facultative pond advantages and disadvantages facultative pond advantages and disadvantages. @,HZK[%w{(>;K7 u("(PgPJhPZeV+Ni9Z;uu7MW]C~~ncyEwv endobj INTRODUCTION An aerated lagoon or aerated basin is a holding and/or treatment pond provided with artificial aeration to promote the biological oxidation of wastewaters. The liner can be clay, asphalt, compacted earth, or another impervious material. The ponds can be used individually, or linked in a series for improved treatment. Rensselaer Polytechnic Institute (RPI), SHILTON, A. <> FPs can result in the removal of 80 to 95% of the BOD5 (SPERLING 2007), which means an overall removal of 95% over the two ponds (AP and FP). facultative pond advantages and disadvantages facultative pond advantages and disadvantages. 2. 0000003487 00000 n Advantages and Disadvantages of Ponds. oKz~[_Zn[U/_Z x2}[[oJ.O_[/k^m~|5J~[\%{Z NCh{!@8]{p.9x^AA* yU2)GbD_.GZ d[GO[tZWv/uK^iMn ^4tM4_i_ B[T[oa0k*ov{k}GIW ePRw4aW/L&i rkUd $_L}~NTA~u]oN2 0000001862 00000 n WSP are also recommended for the treatment in order to reuse the effluent in agriculture and aquaculture, because of its effectiveness in removing nematodes (worms) and helminth eggs (WHO 2006, Volume II), while preserving some nutrients. HWn9 ycf2l2k//%qM7db afUS?_$/X{x 11 0 obj (2003): The service requires full JavaScript support in order to view this website. The top layer of the pond receives oxygen from natural diffusion, wind mixing and algae-driven photosynthesis. 5 0 obj 3m away from the pond surface . Lesson 7: Stabilization Ponds - Mountain Empire Community College Advantages and disadvantages of aerated, partial mix lagoons are listed below: Advantages Require less land than facultative lagoons. Transformation of Waste Stabilization Ponds: Reengineering of an - MDPI PDF Lesson 1 Math Common Lagoon Problems, Two Montana Towns Use Lagoons, For More Information. 20 0 obj To prevent leaching into the groundwater, the ponds should have a liner. PDF FACTATI ODS FACULTATIVE PONDS - snapp.icra.cat ADVANTAGES AND DISADVANTAGES Some advantages and disadvantages of facultative lagoons are listed below: Advantages Moderately effective in removing settleable solids, BOD, pathogens, fecal coliform, and ammonia. During anaerobic digestion, biogas is produced which could be collected by covering the anaerobic pond with a floating plastic membrane (PENA VARON 2004;WAFLER 2008). 22 0 obj endstream endobj Some advantages and disadvantages of facultative lagoons are listed below: Advantages Moderately effective in removing settleable solids, BOD, pathogens, fecal coliform, and ammonia. >}zUv6yS?iQpH3mB.Ib W?C?H' B`6ke@0wUSy=7I ^>z0WZ6n)/j&}. endobj facultative pond advantages and disadvantages endobj facultative pond advantages and disadvantages - Webdirekt.hu These ponds do not require primary treatment and the added depth is needed to handle the substantial increase in solids loadings. <> Facultative waste stabilization ponds, sometimes referred to as lagoons or ponds, are frequently used to treat municipal and industrial wastewater in the . Various case studies are mentioned, e.g. Emery, R. KAYOMBO, S. MBWETTE, T. S. A. KATIMA, J. H. Y. LADEGAARD, N. JORGENSEN, S. E. endobj It is usually arranged diagonally . Convert organic matter in sewage into aquatic crops, fish, waterfowl and other substances, and provide them for human use or other purposes . facultative pond advantages and disadvantages. Pilot studies could demonstrate their performance in the local context; however none of the full-scale applications works. 1. <>stream [11 0 R 12 0 R] 2. If the height difference is large, a multi-stage water drop should be constructed . are widely used in activated sludge process and oxidation ditch process . ICP16009155-1 | Copyright@Qingdao ECHEMI Technology Co., Ltd. Search more information of high quality chemicals, good prices and reliable suppliers, visit, This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. Short factsheet on the design, operation, maintenance and costs of facultative ponds in the United States. The ponds can be used individually, or linked in a series for improved treatment. Waste Stabilisation Ponds is the third volume in the series Biological Wastewater Treatment. endstream facultative pond advantages and disadvantages . The liner can be made from clay, asphalt, compacted earth, or any other impervious material. endobj <> Lagoon Technology International, RPI The inflow of the anaerobic pond should be close to the sludge layer at the bottom . endobj 51 0 obj <> endobj <> Easy to operate. Waste Stabilization Ponds (WSP) | SSWM - Find tools for sustainable Untitled Document [water.mecc.edu] The documented systems, which vary significantly in terms of complexity, performance and costs, range from simple systems for single-house applications (e.g. The initial and operating costs are low.2. Hamzeh Ramadan, Waste Stabilization Ponds - San Diego State University What are the advantages and disadvantages of these three Waste Stablization Ponds listed below: a) Anaerobic Pond, b) Facultative Pond, and c) Aerobic Pond This problem has been solved! typically up to 500 mm). endobj b. Philippines Sanitation Source Book and Decision Aid, Guidelines for the safe use of wastewater excreta and greywater. TVmfn $sx3s \y4 c. Anti-seepage measures must be taken . endobj The two lagoons are operated in series and cover approximately 26 acres. 6R_ (X There are three types of ponds, (1) anaerobic, (2) Advantages and Disadvantages Ponds have many advantages and disadvantages compared to treatment in plants. To remove the algae from aerobic pond, effluents rock filtration, grass plots, floating macrophytes and herbivorous fish can be used, but most commonly, the effluent flows directly in a final maturation pond. These systems are composed of a series of ponds: (1) anaerobic ponds, (2) facultative ponds, and (3) maturation ponds. colleen bready married 6 0 obj WSPs generally produce good-quality effluent in terms of organic matter and pathogen removal, but their application has disadvantages. United Nations Environmental Program - International Environmental Technology Centre (UNEP-IETC) and Danish International Development Agency (Danida), MARA, D.D. The process (as in septic tanks) relies on the sedimentation of settable solids and subsequent anaerobic digestion in the resulting sludge layer. %%EOF 8. a. WSPs are among the most common and efficient methods of wastewater treatment around the world. FACTST FACTATI ODS Operation and Maintenance NBS Technical Details A plant, in contrast, must install an aerator to add oxygen to the water. Oxidation pond for municipal wastewater treatment | SpringerLink Facultative ponds contain a supernatant (upper) layer that is aerobic, and lower layers that are anaerobic. endobj (PDF) Waste Stabilization Ponds: A Viable Alternative for Small %2zFPztVOZT?pI!>?>}{ZOE/ Experts are tested by Chegg as specialists in their subject area. endobj irrigation) or aquaculture (e.g. 2nd Revised Edition, Biological Wastewater Treatment in Warm Climate Regions Volume 1, Training Material on Anaerobic Wastewater Treatment, Greywater Management in Low and Middle-Income Countries, Review of Different Treatment Systems for Households or Neighbourhoods, Guidance Manual on Water Supply and Sanitation Programmes, Advanced Integrated Wastewater Pond Systems, Waste Stabilization Ponds and Constructed Wetlands Design Manual, Design Manual for Waste Stabilization Ponds in Mediterranean Countries. The anaerobic pond must be de-sludged approximately once every 2 to 5 years, when the accumulated solids reach one third of the pond volume. Ponds have many advantages and disadvantages compared to treatment in plants. Index of dept/chem-eng/Biotech-Environ/FUNDAMENT. The principal objective of the study was to asses if existing treatment ponds could be used in the future as thickening ponds for the sludge. macrophyteor fish ponds). facultative pond advantages and disadvantages Additional oxygen can be introduced by wind due to vertical mixing of the water. facultative pond advantages and disadvantages endstream 7 0 obj EMERY, R. PEARSON, H.W. 19 0 obj Lagoons - Purdue University College of Engineering This compendium gives a systematic overview on different sanitation systems and technologies and describes a wide range of available low-cost sanitation technologies. Anaerobic, facultative and maturation ponds as wells as aerated lagoon systems are presented as an appropriate solution in developing countries where sewerage systems are present. Odour problem can be reduced if properly taken into account during the design stage. y"wmlVUvC <> International Water Association (IWA Publishing), Notes in the Design and Operation of Waste Stabilization Ponds in Warm Climates of Developing Countries, Compendium of Sanitation Systems and Technologies. It has the characteristics of realizing the water cycle, which not only saves water resources, but also obtains economic benefits . The lower layer is deprived of oxygen and becomes anoxic or anaerobic. Ests aqu: research opportunities for high school students fall 2021; lakeside high school football; facultative pond advantages and disadvantages 8 0 obj Wastewater stabilization ponds: Principles of planning and practice. };kj?c?k'1$ facultative pond advantages and disadvantages The book presents in a clear and informative way the main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects, operational guidelines and sludge managment for pond systems. Please enable cookies on your browser and try again. [(K London: endobj 12 0 obj <> the wastewater-fed fishponds in Calcutta in India. Please enable JavaScript on your browser and try again. Th~yp.5"j%=D2Bj#=pIq )t$dILVHkTn}$2YXZgla)hI,?>h6s[,7oJD8nx?W?m/ endobj Case Study on the fishponds in sewage-fed lagoons in Kolkata. What are the advantages and disadvantages of these three Waste Stablization Ponds listed below: Perspectives are different frameworks from which to explore the knowledge around sustainable sanitation and water management. You will be redirected once the validation is complete. 0000002114 00000 n High self-help compatibility concerning maintenance. 9 0 obj <> % The 55 chapters are divided into 7 parts over two volumes: Volume One: (1) Introduction to wastewater characteristics, treatment and disposal; (2) Basic principles of wastewater treatment; (3) Stabilisation ponds; (4) Anaerobic reactors; Volume Two (also available in the SSWM library): (5) Activated sludge; (6) Aerobic biofilm reactors; (7) Sludge treatment and disposal. www.waterworld.com is using a security service for protection against online attacks. They use less energy than most waste water treatment methods. The sewage treatment stabilization pond system can be used to make use of abandoned rivers, swamps, canyons, abandoned reservoirs and other areas. An aerobic pond is commonly referred to as a maturation, polishing, or finishing pond because it is usually the last step in a series of ponds and provides the final level of treatment. 'b* [V;.Kih+'^\j_.OUzwt^ tah;,zGb'hLOY k_!uJUu^zX{h @cxxZIup y,"hA}[ russian central bank rothschild. The direction from import to export should avoid the prevailing local wind direction throughout the year to prevent odor pollution . The most serious disadvantages are a long retention time, the release . facultative pond advantages and disadvantages. 51 21 2. 12 0 obj Unless they are property maintained, lagoons can provide a breeding area for mosquitoes and other insects. 3 0 obj 0000001707 00000 n x[:4iMH8y'8`"mPIB?/=}~#2,X0@1M?#_73?|qwfTf?i$"1l}8 p\@TeK,O#yFd(rg?dbi'p?,>,Pz|= ? The book covers the main treatment processes used worldwide with wastewater treatment in warm climate regions given a particular emphasis where simple, affordable and sustainable solutions are required. <> Stabilisation ponds also have the advantage of very low operating costs since they use no energy compared to other wastewater treatment technologies and only low-tech infrastructure (see also operation and maintenanceand ensuring sustainability). Waste Stabilization Ponds (WSPs) are large, man-made water bodies. Dar es Salaam/Copenhagen: facultative pond advantages and disadvantages In cold climates, the HRT and loading may be adjusted. <> % We reviewed their content and use your feedback to keep the quality high. Technologies for these sanitation options are presented. Pond Treatment Technology. 1 0 obj advantages and disadvantages of communication accommodation theory The algal production of oxygen occurs near the surface of aerobic ponds to the depth to which light can penetrate (i.e. If used in combination with algae and/or fish harvesting, this type of pond is also effective at removing the majority of nitrogen and phosphorus from the effluent (TILLEY et al. The stabilization pond is located in the natural environment, and the climate has a great effect on it . CHrc!xGEc3"Xes.pS`yqGR9)G2 2 0 obj Advantages of WSPs are Lagoon systems can be cost-effective to design and construct in areas where land is inexpensive. (b) (i) Considering the discharge of organic effluent into a river, compare the processes of reaeration of the stream and the rate of decomposition of the organic waste for the four different zones of the polluted stream The technical content was reviewed by Prof. Duncan Mara (University of Leeds, England). aspects and provides practical information on design, financing and planning of faecal sludge treatment plants. ifk ume tvlingskalender / facultative pond advantages and disadvantages. Facultative and anaerobic ponds may be charged with high-strength wastewater. <>/Metadata 2123 0 R/ViewerPreferences 2124 0 R>> Effluent from some types of lagoons Contains algae and often requires additional treatment or polishing to meet discharge standards. Effluent treatment standards that are currently accepted in order to protect public health and safety are reviewed. <> 6 0 obj 0000006296 00000 n 71 0 obj<>stream What are lagoon systems?, Advantages and Disadvantages of Lagoon Systems, Two, Three or Four Lagoons are Better than One, Facultative Lagoons Treat Wastewater Naturally, Lagoons Use Simple Design, Lagoons Need Proper Operation, Maintenance, . The supporting information includes a standard systems approach which can be adopted universally; the theoretical background on the biological, chemical and physical processes of each method, the current state of the technology and technical knowledge on how to design, operate and maintain them; and theoretical knowledge on how best the models may be used to describe the systems. The concept of managing urban wastewater flows at a decentralised or "intermediate" level, based on micro watersheds, is explored. {z,B2Y\jkU5^IwYf0i4jfm]pRwI 5|Y0##ju?iV/HUsLgNWnf.0ykr&^:]?+dg"#{!K8?~yO?=~RJ{/6jo1eH98J^0z25&\N;2^,<7G(lH=Nh`/w=epGE +Y&\pgc6+V:P#ZGU_ ZvQ z s_:n*yU!2]WYy\=M56mzWKYx"gR[5] %-&: YfsQqrll1 SbRQrUpIo^NcRj? (9k|6m}ue|dU?1gXD.Rw Tv}~MF+_HW#?xWe8&. irrigation) or aquaculture (e.g. u"d u={7}Y"0X@/1` >#*J9:$x.W[9s!96$Yp3hb30%$'~jVu+ =ZM $O$RAashl6=OTSX\/Zct+HoX,/"5-[j@*y| The Clinton Water District provides a secondary level of wastewater treatment by using a facultative lagoon system. A Century-old Innovation of Farmers. BOD removal in both types of facultative pond is in the range 60-80%. 2003-2023 Chegg Inc. All rights reserved. endobj 5 Stabilizing the pond body and its inlet and outlet, (1) Design points of the stabilization pond. HP@)54]n8>X Ideally, several aerobic ponds can be built in series to provide a high level of pathogen removal. The size and number of maturation ponds depends on the required bacteriological quality of the final effluent. endobj Aerobic ponds are usually between 0.5 to 1.5 m deep with a detention time of 15 to 20 days . Wastewater Use in Agriculture, Compendium of Sanitation Systems and Technologies (Arabic), Epuration des eaux uses par Lagunage a Microphytes et a Macrophytes en Afrique de l'Ouest et du Centre- Etat des lieux, performances puratoires et critres de dimensionnement, How to Select Appropriate Technical Solutions for Sanitation, Environmentally sound technologies in wastewater treatment for the implementation of the UNEP/GPA "Guidelines on Municipal Wastewater Management", Lagunas de Estabilizacion para Descarga de Liquidos de Camiones Atmosfericos, Ecological Sanitation and Reuse of Wastewater. 7) Ponds with upper portion _____ and the bottom portion _____ are called facultative ponds. 2008). www.waterworld.com is using a security service for protection against online attacks. 1992; SASSE, 1998; TILLEY et al. 5 0 obj For facultative ponds sludge removal is even rarer and maturation ponds hardly ever need desludging. Odor can become a nuisance during algal blooms or with anaerobic lagoons and lagoons that are inadequately maintained. a) Anaerobic Pond, <>stream (2014): clarins or charlotte tilbury. <> T$1MoG##}vQP"$=q^(XknABEo2$ w6+,i~}v_4S22$p_h+r"\v+xU~56Uu_AtW`:1ci0whs1VSJpANM9qAn@WM>u.E YD O=Sl <> For multi-level stabilization ponds, separate gates should be set up at each entrance and exit of the stabilization ponds at all levels . A sample design exercise and some technical drawings and sketches are also given. G 6fo/lpn`n4JH@29h7g0\{f. 9w.OW x2 eM';j OB"#A}zC 3tkIt@v~o? . However, large surface areas and expert design are required. !J=WIt@XY>APw~4 r89>g)#l0|#@d{&9 However, this depends on the availability of land and its price. The pond body is generally rectangular, and the corners should be rounded . The effluent from lagoon systems can be suitable for irrigation (where appropriate), because of its high-nutrient and low pathogen content. 0000001295 00000 n High efficiency while very simple operation and maintenance. Solved 3. (a) (0) How would you describe a facultative pond - Chegg 8 0 obj Stabilization ponds are a very promising sustainable centralized wastewater treatment option for West Africa due to the favourable climate. The major topics covered are: microbiology and ecology of wastewater treatment, reaction kinetics and reactor hydraulics, conversion of organic and inorganic matter, sedimentation, aeration. Your email address will not be published. Biological Wastewater Treatment in Warm Climate Regions gives a state-of-the-art presentation of the science and technology of biological wastewater treatment, particularly domestic sewage. 2 0 obj H3P0 t^#ssC=sSc3Ke "Rxx- L $adPWS & Yfa endobj 9 0 obj Technical information on environmentally sound technologies in wastewater treatment. 8. Stabilization ponds are the preferred wastewater treatment process in developing countries, where land is often available at reasonable opportunity cost and skilled labour is in short supply. 0000000729 00000 n PDF Secondary Wastewater Treatment (Waste Stabilization Ponds) The service requires full cookie support in order to view this website. At peak sun radiation, the pond will be mostly aerobic due to algal activity, while at sunrise the pond will be predominantly anaerobic (ERTAS et al. They are not appropriate for very dense or urban areas. %PDF-1.7 PDF Wastewater Technology Fact Sheet: Facultative Lagoons However, bad odour cannot be avoided reliably with high loading rates. WSPs are particularly well suited for tropical and subtropical countries because the intensity of the sunlight and temperature are key factors for their efficiency (IRC 2004). This publication deals with the feasibility of waste stabilisation ponds for the simultaneous treatment of collected sludge (by vacuum trucks) and wastewater from the domestic sewer system. 6) _____ Ponds have no dissolved oxygen throughout. The anaerobic pond is the primary treatment stage and reduces the organic load in the wastewater. The purpose of this guide is to assist local contracting authorities and their partners in identifying those sanitation technologies best suited to the different contexts that exist within their town. 0000003742 00000 n stream WELL - Resource Centre Network for Water, Sanitation and Environmental rate of 0.6 m 3 of facultative pond effluent per m of RF volume per day was about 9 mg BOD, about 7 mg SS, about 3 mg ammonia-N per liter and 10 to 1,000 fecal coliforms per 100 mL. facultative pond advantages and disadvantages myer hr contact 5 Stabilizing the pond body and its inlet and outlet (1) Design points of the stabilization pond _____ [/PDF/Text/ImageB/ImageC] PDF United States Environmental Protection Agency Wastewater Technology There are three types of ponds, (1) anaerobic, (2) facultative and (3) aerobic (maturation), each with different treatment and design characteristics. For the restricted and unrestricted reuse of the effluent in agri- and aquaculture, please refer to the WHO (2006) guidelines. Facultative ponds typically range from 3 to 8 feet in depth. www.waterworld.com is using a security service for protection against online attacks. T w"F:ddH^0% /@ 0[#a%KI E@' _{a~d Q/d"8+ .U p9 GG^tS~0-o_Oa/Vxi>5IJvo}=~4iKuz};p/^x],;^{?-{m*:Vt7u@@7*@ y;tv DG3H.>k+>'//_^V^vzK_^|.^a{uw]+uOZ{uu_Q`dIvP$#&fGF#R0=_ppV f=]%&z\/_uvz/.}=ko_an_]I&^z}-o]_s! N-^WJCQoU8lgL^laYXk lq5!JWDlpDS|WqxHlwaB#5nJy>y8b5:ypcluxqu6/*W!9?G! !J=WIt@XY>APw~4 r89>g)#l0|#@d{&9 a. 4 0 obj }{]7%DAZDnO?3CK=Z.l8P*`wR7Oe! <>/Font<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 720 540] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> 0000003245 00000 n 3. Wastewater treatment - Food and Agriculture Organization Advantages C Simple, reliable, biological process. Perspectives are like filters: they compile and structure the information that relate to a given focus theme, region or context. (2004): WSPs are low-cost for O&M and BOD and pathogenremoval is high. Oxygen is unable to be maintained at the lower layers if the pond is too deep, and the colour too dark to allow light to penetrate fully or if the BOD and COD in the lower layer is higher than the supply. %PDF-1.3 facultative pond advantages and disadvantages - Zolucky.sale It covers both technical and non-technical (socio-cultural, economic, political etc.) As the wastewater flows over the . (We`ll never share your email address with a third-party.). This is the Arabic version of the Compendium of Sanitation Systems and Technologies. series of vertical and horizontal-flow planted soil filters). Waste Stabilization Ponds: A Design Manual for Eastern Africa. Introduction to Wastewater Treatment Ponds | WaterWorld 0000002729 00000 n endobj 4 0 obj 7 0 obj <> (1992): It explains requirements to promote the safe use of wastewater in agriculture, including minimum procedures and specific health-based targets, and how those requirements are intended to be used. ^ZJw\xw@y9/#}m]Y"}. endobj -Mx-BGT""D4h0D BOToBr M v:]O%W!dR5!Cd6h"0 ;(S#fn@8l.A="ps<2xCDT9]h2 f!@eu8\&eq!C@2G,r9#e5P'+@6pdqC4:5aGO\OOY|:A` =~uA.OONaS='t> *>o{ ":QwONp'KO~OmOo X\"di0'x? ALABASTER, G.P. 0000001158 00000 n Settleable solids accumulate and are digested on the bottom of the pond. facultative pond advantages and disadvantages facultative pond