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Decentralized wastewater treatment systems (DEWATS) for the Slaughterhouse of the City of San Fernando, La Union
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Decentralized wastewater treatment systems (DEWATS) for the Slaughterhouse of the City of San Fernando, La Union

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prepared by P. C. Ortega*, V. M. Valdez*, L. C. Balanon*, F. G. Decena*, R. D. Medrano*, E. Estillore* & C. H. Jucutan* *City of San Fernando, La Union, Philippines for Decentralized Wastewater …

prepared by P. C. Ortega*, V. M. Valdez*, L. C. Balanon*, F. G. Decena*, R. D. Medrano*, E. Estillore* & C. H. Jucutan* *City of San Fernando, La Union, Philippines for Decentralized Wastewater Treatment Systems (DEWATS) for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).


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  • 1. Decentralized wastewater treatment systems for the Slaughterhouse of the City of San Fernando, La UnionP. C. Ortega*, V. M. Valdez*, L. C. Balanon*, F. G. Decena*, R. D. Medrano*, E. Estillore* & C. H.Jucutan**City of San Fernando, La Union, Philippines Abstract: The planning, implementation and operation of the City of San Fernando’s Slaughterhouse Wastewater Treatment Facility provides many lessons on the benefits and challenges of implementing Decentralized Wastewater Treatment Systems (DEWATS). Through the implementation of this system and others like it, San Fernando is achieving its vision of becoming a center of innovative wastewater technologies. The wastewater treatment facility at the slaughterhouse was conceived because of the insufficient treatment being conducted previously, consisting of a one-chambered septic tank and an open lagoon. The newly constructed DEWATS, developed in cooperation with BNS-BORDA and funded by the Congressional Development Fund (CDF) of Congressman Victor. F. Ortega, began operation in January 2011. It has significantly improved the quality of the effluent as well as eliminating odours, containing all wastewater underground, and creating an aesthetically pleasing area. The exemplary case of the San Fernando City Slaughterhouse illustrates the obligatory need but also benefits of investing in wastewater treatment infrastructure. Keywords: environmental sanitation; slaughterhouse; decentralized wastewater treatment systemINTRODUCTIONSan Fernando, La Union is a city of 120,850 located on the South China Sea about 270km north of Manila. It is a regional hub for travel, trade, and governance. It is also a citythat is committed to sustainability. A number of environmental projects have beenembarked upon in San Fernando, in areas of solid waste management, coastalresource management, forest resource management, and wastewater management.While all these projects are important for the health of San Fernando’s citizens and itsenvironment, sanitation emerges as a key issue which the city has committed toaddress through a variety of means.Against this political backdrop, the issue of San Fernando’s slaughterhouse emerged.The slaughterhouse suffered from poor wastewater treatment, leading to bad odors andcontaminated groundwater. In a collaborative effort, the City implemented a newwastewater treatment system - emphasizing efficiency and environmental sustainabilitythrough their planning. The completed system, while faced with several unresolvedproblems, can easily be considered a success for San Fernando’s innovativewastewater treatment planning process. Further, its slaughterhouse wastewater
  • 2. management serves as an informative example for other cities seeking to implementeffective decentralized wastewater management systems.CITY OF SAN FERNANDO: BACKGROUNDThe City of San Fernandos commitment to wastewater management began with thevision of former Mayor Mary Jane Ortega - in office from 1998-2007 - and has continuedunder the leadership of the current Mayor, Pablo C. Oretga. The citys increasingnumber of sanitation projects are beginning to draw attention to the city from otherareas in the Philippines and around the world. San Fernando aims to be a center fordiversified wastewater technology. By piloting a variety of wastewater treatment options,San Fernando will be able to learn which function best for itself, as well as providing aconvenient location for study tours for other LGUs.In 2005, this vision produced its first pilot project, in the form of ecological sanitation(eco san) toilets, in one coastal and one mountainous barangay. Eco san is a waterlesstechnology that relies on separating urine and faeces so that they can be processedseparately. In 2006-2007, the Fishermans village, a public housing project to relocatemarginalized people living in vulnerable coastal areas, was outfitted with 86 eco-santoilet units. This initiative was spearheaded by a city partnership with the Center forAdvanced Philippine Studies.San Fernando continued its innovative sanitation projects with a hybrid anaerobic andaerobic waste water treatment plant for the city public market in 2006, in partnershipwith USAID. The city is also currently in the process of installing Eco-Tanks, small scalesewerage treatment facilities that collect wastewater into a tank to be purified, inpartnership with CityNet, USAID, and Rotary International. One tank is already installedand operational, and plans are well under way for installation in two more barangays.Finally, the construction of a Septage Treatment Facility has begun in 2011. This willallow the implementation of septic tank desludging for all households and commercialestablishments in San Fernando.Among all these sanitation projects, the decentralized waste water treatment facility atthe slaughterhouse stands out as project that took a poorly functioning waste watertreatment facility and transformed it into a cleaner, more aesthetically pleasing, andeasier to maintain system. It uses a different technology than that of the market wastewater treatment facility, requiring very little maintenance because the process is non-mechanized. The city believes that projects like these are important, especially in lightof the current initiative to begin having residents pay a waste water management fee: byfocusing on city-owned generators of highly contaminated waste water, the governmentdemonstrates its own commitment and encourages the commitment of its residents.
  • 3. THE SLAUGHTERHOUSEThe slaughterhouse in San Fernando was built in 2000, after moving from its previouslocation near the city market (actually the current location of the market wastewatertreatment facility). It is owned by the city government and is located in Barangay Tanqui.Around the property lies a creek to the East, an elementary school to the South, andrice fields to the North and West. A police station is also nearby. The slaughterhouseprocesses 80 hogs, 6 cattle, 2 carabao, and 10 goats daily. The meat from theslaughterhouse is transported to the city market, where it has the potential to reach anyof the city’s more than 120,000 residents. Meat production is highly sensitive tocontamination by germs and bacteria. From the cleaning of animals both before andafter the slaughtering process, the slaughterhouse produces between 12 to 13 cubicmeters of wastewater per day. Wastewater discharged from a slaughterhouse has acomplex composition and is harmful to the environment; it is much stronger thandomestic or municipal wastewater. After an initial screening of coarse solids,slaughterhouse wastewater is mainly composed of diluted blood, fat, and suspendedsolids and may also contain some manure. It is generally reddish brown to dark brownin colour and can have an objectionable odour. If untreated wastewater is discharged tocreeks, rivers and streams, the wastewater contributes significant levels of biologicaloxygen demand (BOD) and other nutrients which cause pollution to the body of water(BORDA, 2010).Because of these dangers, it was an obvious choice for the city to adopt a project toproperly treat the wastewater from the slaughterhouse. Several goals wereaccomplished in the process: the demonstration of a new decentralized wastewatertechnology, the improvement of the appearance and smell at the facility, amelioratingthe quality of the effluent being discharged to comply with current standards andregulations, increasing the safety of the meat produced, and generally creating acleaner environment.Slaughterhouse: Pre-DEWATSPre-renovation, the slaughterhouse wastewater treatment process consisted of a simpleprocess of sedimentation, percolation, evaporation and aeration, through a septic tank,grease trap and open lagoon. Taken as a whole, the process lacked efficiency inproperly treating the wastewater and mitigating odors. Some wastewater was allowed toseep into the ground, contaminating underground impoundments. The open lagoonallowed wastewater to decompose uncovered, creating odors which affected thesurrounding community. The problems associated with open systems were furtherexposed as jeepneys and tricycles were washed beside the lagoon, allowing oil andgrease to flow into the system, neither of which it was designed to handle. Further, theeffluent was allowed to flow, incompletely treated and untested, into a nearby creek.The still-hazardous wastewater sat stagnantly during the dry season; sinking into theground and again contaminating the groundwater. Complaints of foul smells, dirtysurroundings, flies and untreated water are all symptomatic of a treatment processwhich failed to close biological circles, thus falling short of sustainability in the ecologicalor sociological sense of the word.
  • 4. IMPLEMENTATION OF WASTEWATER TREATMENTImplementation process: How did DEWATS come to the slaughterhouse?After the construction of the waste water treatment facility at the market and the variouspartnerships with the Center of Advanced Philippine Studies (CAPS) and USAID, theCity was inspired to take action on wastewater treatment at the slaughterhouse. Cityrepresentatives from a number of departments visited several other wastewatertreatment facilities in other cities in the Philippines, where the concept of DEWATS wasdemonstrated. On April 17, 2007, government officials from San Fernando, led byMayor Mary Jane C. Ortega, attended a presentation by BNS-BORDA on DEWATS andhow it could be applied in San Fernando. A site visit to the slaughterhouse wasconducted after the presentation to determine if the technology proposed by BORDAwould be appropriate for the site. Since then, a decision was made to undertake theproject. However, construction was delayed due to the previously plannedimprovements to the slaughterhouse and the challenge of locating proper funding. In theend, the project was funded through the Congressional Development Fund (CDF) ofCongressman Victor F. Ortega. The construction of the wastewater treatment facilitytook place from October to December 2010, and operation began in January 2011.Description of technologies and treatment processThe completed wastewater treatment system at the slaughterhouse functions withoutmechanization or chemical inputs. The wastewater enters the biogas digester, wherethe digestion process produced methane gas. The accumulation of pressure from thegas pushes the wastewater into the settler, baffle reactor and anaerobic filter. Here, thewastewater is retained for a set period of time, to ensure proper water quality.The biogas digester allows the elements of the wastewater to decompose into theirindividual components, one of which is methane gas. The gas can subsequently be re-used elsewhere in the slaughterhouse operation.The baffle reactor consists of a series of chambers which mixes the wastewater withsludge, thus aiding the process of bacterial digestion of the wastewater.The anaerobic filter circulates wastewater past micro-organisms which consume thehazardous BOD and ammonia contained within.The gravel filter exposes the wastewater to the biological community associated withthe roots of the plants grown throughout it. Oxygen also reaches the wastewaterthrough the plant roots, aiding in its treatment.Each individual element in the treatment process is designed to function in coordination
  • 5. with the elements before and after it, thus increasing the efficiency of the whole. Forexample, the anaerobic filter removes all solid particles, so that the gravel filter intowhich the wastewater flows next does not become clogged, and is able to filter thewater with little maintenance. The gravel filter also allows wastewater to travel just 5cmunder the surface - a small design feature which eliminates odor entirely. The anaerobicfilter and biogas digester are similarly low maintenance, due to the carefully coordinatedflow of wastewater from one end of the system to the other; reaching each new elementwhere it can be treated most efficiently.The wastewater treatment system, as previously constructed, was not adequate for theamount of wastewater flowing through it. An essential component of the new plan,therefore, was the scaling-up of the treatment facilities to match the quantity ofwastewater being sent from the slaughterhouse. The biogas digester, anaerobic bafflereactor, anaerobic filter and planted gravel filter were all constructed at such a size as tobe well suited to manage the 12-13 cubic meters of wastewater that the slaughterhouseproduces daily. Having carefully measured the amount of wastewater before designingthe treatment technologies, the city was able to construct them in such a way that thewastewater is treated on the most efficient scale, through the most efficient meanspossible.OPERATION: DECENTRALIZATION SUCCESSES AND REMAINING ISSUESThe underlying principles of the DEWATS system at the slaughterhouse are efficiencyand sustainability. With capital costs now invested, the sustainability of the new facilityis perhaps best exemplified in the fact that maintenance costs are now minimal. Thechemical and biological efficiency of the system allows for very simple maintenance, asnatural processes are allowed to occur in an unobtrusive manner. No odor is emittedfrom the underground systems, nor from the gravel pit. The common complaints ofsmells, dirty surroundings and flies are all alleviated by a design which does not exposethe wastewater to open air until it flows into the creek after treatment.The passive system requires no electricity, and very little maintenance. Once a week,the manholes above the baffle reactor need to be opened and the reactor inspected toremove any scum or solid particles that may have accumulated. Large pieces of debrisalso need to be filtered and disposed of as the wastewater exits the slaughterhouse andenters the treatment gauntlet. By reducing the need for extensive maintenance, the Cityof San Fernando has also saved the money that would have been necessary to pay formore maintenance workers, in addition to the repair costs associated with active,electrically-powered systems.
  • 6. Remaining issuesSome issues remain in the sustainable treatment of the slaughterhouse wastewater.The primary concern is that effluent is still not up to DENR Class C standards, indicatingproblems somewhere along the way. However, as the City learns from continuedoperation and management of the DEWATS system, they are confident that solutionscan be found for all these problems.Plants in the gravel pit have not been growing as quickly as expected (and, in somecases, are dying). The root systems of the plants were a key element in the filtration ofthe water, and the lack of substantial root development may be one of the reasons whythe final effluent is not up to the required standards. Additionally, staff at theslaughterhouse have been thus far unable to procure replacement plants, so as to bringthe wastewater into contact with oxygen, lessening the smell. The source of the plantfailure remains undetermined, an unknown which slaughterhouse officials hope torectify before bringing in new plants. There is some unused space between the gravelpit and the creek which could have been used to expand the gravel pit, potentiallyaffecting the efficiency of the aerobic process. Frequent desludging of theslaughterhouse septic tank has also been necessary - once in the first three months.While wastewater is strained for large objects before entering the septic tanks, debrisitems such as horns and hoofs are finding their way into the tanks, causing prematurebuildups.A collaborative process was instrumental in bringing the slaughterhouse project tofruition, with many different stakeholders and government agencies providing inputduring the planning process. This management configuration, while successful duringthe planning stages, has recently led to some miscommunication in regards tomaintenance responsibilities (generally no more than one hour per day). Currently, theCity Environment and Natural Resources Office (CENRO) is conducting quarterlymonitoring of the effluent from the DEWATS. The results of the monitoring by CENROhave produced recommendations for troubleshooting and maintenance. The CityVeterinarian Office has a claim to responsibility for maintenance and operation throughtheir on-site presence in managing the slaughterhouse, and the technical expertise ofthe City Engineering Office makes it another potential candidate for leadership. Some ofthis confusion can perhaps be expected, as the DEWATS operation is still in its initialphase. Moving forward, the identification of clear roles for the various groups involvedwill be important for troubleshooting and maintenance activities.
  • 7. LESSONS LEARNED FOR DECENTRALIZED WASTEWATER MANAGEMENT ANDPLANNINGThe wastewater treatment facility at the slaughterhouse has been in operation for lessthan half a year. While implementation has not been without its hitches, withoutquestion the new facility constitutes a vast improvement over the old one. Major lessonsinclude the importance of leadership, designing technologies to scale, and properplanning so as to minimize the need for maintenance.The successes of the new treatment system can largely be traced to a planning processwhich took sustainability and efficiency into account, thus diminishing the need forongoing management as an important variable in continued high effluent quality.Although some issues remain, the overall efficiency of the system is such that no newstaff had to be hired in order to run or maintain the treatment process. Existing staffhave thus far been capable of performing the occasional routine tasks necessary to thecontinued efficiency of the system. Although long-term sustainability cannot yet beempirically proven, it seems likely that most of the problems presented are not structuralin nature, and can be resolved through relatively minor changes to the system.Leadership has also been a key factor in every stage of the planning andimplementation process. Without the vision of elected officials, San Fernando wouldnever have begun its journey to be a center of diverse sanitation technologies.Committed public servants have been essential in overseeing the project from itsinception; they have demonstrated continued determination to resolve the problems,both managerial and operational, that have come up during this process.Decentralized technologies have worked well for San Fernando for many reasons. Bybuilding a DEWATS specifically for the slaughterhouse, the system was able to addressthe unique aspects of the wastewater coming from that facility, where a morecentralized system would not have been able to do so. There is also a much lower costin creating smaller facilities to treat specific needs. The decentralization of wastewatertreatment is what has allowed San Fernando to diversify its sanitation technologies andthus become an example for other cities.CONCLUSIONThe City of San Fernando’s commitment to effective, sustainable sanitation has bornefruit in the new slaughterhouse wastewater treatment facility. The approach is at onceforward-thinking and simple; a product of strong long-term planning. Efficientwastewater treatment at the slaughterhouse site provides a decentralized solution towhat is otherwise a complex problem of attempting to manage the health of 120,000people. San Fernando has learned from its extensive study of projects throughout the
  • 8. Philippines, and through the numerous innovative sanitation projects piloted within SanFernando itself. It is through these trials and observations that San Fernando has beenable to parse that which fits its particular needs in the unique circumstances of theslaughterhouse, and to implement a solution tailored to the problem. San Fernando’sslaughterhouse DEWATS stands as a legitimate success for appropriate and effectivesystems.ReferencesBNS-BORDA (2009) Preliminary Concept of Decentralized Wastewater Treatment Systems for City Abattoir of SanFernando, La Union. Quezon City, Philippines.EMB-DENR (2005) DENR Administrative Order No. 2005-10 Implementing Rules and Regulations of the PhilippineClean Water Act of 2004 (Republic Act No. 9275).