PH 136 Environmental and Occupational Health: Excreta Disposal PDF

PH 136: ENVIRONMENTAL AND OCCUPATIONAL HEALTH EXCRETA DISPOSAL Engr. Romeo R. Quizon | February 3, 2025 ○​ Residues and waste widely spread → generates OUTLINE...

PH 136: ENVIRONMENTAL AND OCCUPATIONAL HEALTH EXCRETA DISPOSAL Engr. Romeo R. Quizon | February 3, 2025 ○​ Residues and waste widely spread → generates OUTLINE geophysical and environmental hazards A.​ Environmental System ​ Examples: a.​ Components of the Environmental System ​ Improper disposal of excreta → biological B.​ Excreta hazards a.​ Human Excretions b.​ Components of Excreta ​ Improper use of reagents → chemical i.​ Solid Fraction hazards ii.​ Organic Fraction iii.​ Nutrients (N, K, P) COMPONENTS OF THE ENVIRONMENTAL SYSTEM iv.​ Pathogenic Organisms Life-Support Systems c.​ Bacterial and Chemical Soil Pollution Patterns i.​ Movement of Pollution in Dry Soil ​ Energy ii.​ Movement of Pollution in Underground Water ○​ Nutritive 1.​ DOH ○​ Non-nutritive 2.​ Septic Tanks ​ Social Environment 3.​ National Building Code ​ Built Environment C.​ Environmental and Health Impact ​ Geophysical Environment a.​ Turbidity ○​ Air b.​ Oxygen Depletion c.​ Eutrophication ○​ Land d.​ Diseases ○​ Water i.​ Water-related Diseases ii.​ Excreta-related Diseases Human Activities iii.​ Categories ​ Work iv.​ Health Impacts of Sanitation Improvements ​ Recreation e.​ Health Impacts ​ Residential D.​ Excreta Disposal Facility ​ Transportation a.​ General Considerations i.​ Cultural Acceptability Environmental Hazards b.​ Sanitation Systems ​ Site and Location i.​ Sanitation Technology Options ii.​ Onsite Sanitation ​ Biological iii.​ Off-site Sanitation ​ Chemical iv.​ Community-Scale Sewage Treatment ​ Physical Processes ​ Psychological E.​ Sewage Treatment Facility ​ Sociological a.​ Community-Scale Sewage Treatment Processes b.​ Sewerage and Sewage Disposal Residues and Waste c.​ Waste Stabilization Ponds ​ Solid wastes d.​ Resource Recovery ​ Gaseous/Air Pollutant F.​ References G.​ Review Questions ​ Liquid - result in water pollution ​ Excreta ENVIRONMENTAL SYSTEM EXCRETA ​ Waste excreted from our body ​ Consists of feces and urine ​ Main source of pathogenic microorganisms ​ Discharged by water → this water becomes wastewater containing the excreta HUMAN EXCRETIONS ​ The following are components of urine and feces which are regarded as inorganic chemicals and major components of fertilizers: ○​ Nitrogen ○​ Phosphorus ○​ Potassium Table 1. Human Excretions Composition. COMPONENTS OF HUMAN EXCRETIONS Figure 1. Components of the environmental system. Fertilizer Urine Feces Total 230 kg ​ Life support systems are the basis for human activities 30-50 L 30-50 L cereal ​ Human activities generate residues, wastes, and N 3.1-5.6 kg 0.09 kg 3.4-5.7 kg 5.6 kg environmental hazards P 0.24-0.4 kg 0.19 kg 0.36-0.6 kg 0.7 kg ○​ One of which includes liquid waste: excreta K 0.6-1.0 kg 0.17 kg 0.72-1.2 kg 1.2 kg ○​ Residues and waste improperly managed → affect Total NPK 94% 6% 4.5-7.5 kg 7.5 kg life-support systems = air, water, or land pollution Pathogen 4 15 #MagkabigkisBenteSais Team 04 | 1 of 12 ​ Urine has a high nutrient composition with only a minimal ○​ The vertical/downward movement of excreta is only content for pathogens. limited to 3 meters ○​ Urine once oxidized → urea → ammonia → nitrite ○​ The lateral movement is only limited to 1 meter (unstable form of nitrogen) → nitrate (stable form) ○​ There is no way for the groundwater to become ​ Feces are low in nutrients but high in pathogens. polluted ​ Three possible components as pollutants: ○​ True in mountainous/hilly areas (e.g., Antipolo) where ○​ Chemical: NPK, nutrients the groundwater is found way deeper than the septic ○​ Pathogen tank ○​ Feces in the form of organic matter COMPONENTS OF EXCRETA SOLID FRACTION ​ Total Solids ○​ Residue at 103-105 ​ Settleable Solids ○​ Settle down because they are heavier than water ​ Filterable ○​ Colloids and dissolve solids (e.g., sugar and coffee) Figure 3. Illustration of Scenario B. ​ Non-Filterable ​ Scenario B: Constructing a septic tank that reaches the ○​ Suspended solids (minute and small) groundwater ○​ Very light, so they are just floating on water ○​ The movement of the pollutants will flow along the ○​ Hardest to remove from water direction of the groundwater ○​ Sometimes, coagulants are added — these are ○​ Velocity of groundwater under normal conditions: 1-3 chemicals that cause flocculation when mixed into m/year water and stirred uniformly ​ It will be faster if the soil consists of stones or ​ During this process, the coagulants help rock suspended solids attach to each other, forming flocs. As the flocs become heavier, they separate MOVEMENT OF POLLUTION IN UNDERGROUND WATER from the water. ORGANIC FRACTION ​ 75% of Suspended Solids (SS) and 40% of Fecal Sludges (FS) ​ Compounds which possess one carbon atom ○​ Serves as food for the microorganisms ○​ Carbon will bond with oxygen → decomposition of organic matter Figure 4. Illustration of Scenario C. NUTRIENT NITROGEN + PHOSPHORUS + POTASSIUM ​ Nitrogen and phosphorus are both active ingredients of ​ Scenario C: Source of pollution located DOWNSTREAM fertilizers from the source of water ○​ Essential to the growth of protists and plants ○​ Groundwater will NOT be polluted ​ Nitrogen and phosphorus are both inorganic chemicals PATHOGENIC ORGANISM ​ Disease-causing organisms (e.g., bacteria, viruses, parasites) that can come from human or animal excreta ​ Survive at body temperature (36–37°C) BACTERIAL AND CHEMICAL SOIL POLLUTION PATTERNS MOVEMENT OF POLLUTION IN DRY SOIL Figure 5. Illustration of Scenario D. ​ Septic tanks are NOT cemented at the bottom, so both chemical (nutrients) and bacterial (pathogens) pollutants of ​ Scenario D: Source of pollution is UPSTREAM from the every excreta deposited will travel downwards water source ○​ There is a high probability that the groundwater will become contaminated Figure 2. Illustration of Scenario A. ​ Scenario A: Constructing a septic tank in dry soil where the groundwater is very deep Figure 6. Top view of pollution movement. PH 136 | Excreta Disposal 2 of 12 ​ Source: Septic Tank ENVIRONMENTAL AND HEALTH IMPACT ​ Bacterial Pollutant: 5 m + 6 m = 11 meters traveled TURBIDITY ​ Chemical Pollutant: 25 m + 90 m = 115 meters covered in the form of NPK ​ Results of solids directly discharged into receiving bodies of water DOH ○​ Common signs in mining areas or after heavy rains ​ Required to construct water sources 25 meters away from ​ Result to heavy siltation and eventually flooding the source of pollution ○​ Setting down of solids will lead to reduction of the ​ This is done to protect us from contamination from depth of the body of water bacterial pollutants: ​ May harm aquatic animals ○​ Chemical pollutants like NPK DO NOT have health ​ Sunlight (solar energy) cannot penetrate into deeper effects for normal people water bodies; thus, depriving aquatic animals of solar ○​ However, it can cause Methemoglobinemia or Blue energy Baby Syndrome (oxygen starvation) when consumed ​ Solids enter through gills of fish leading to suffocation, by infants injury, infection, and death ​ Water contains nitrogen in the form of nitrate ​ The bacteria in the baby’s system will convert DEPLETION OF OXYGEN nitrate → nitrite → unstable → gets oxygen ​ Result of discharging organic matter along with the from the blood → baby will become deprived excrete into bodies of water of oxygen Septic Tanks ​ Septic tank consists of two chambers: ○​ Digestive chamber ○​ Leaching chamber ​ Open, not as cemented (probability to contaminate the groundwater) ​ Advantages ○​ Flexible and adaptable to a wide variety of household waste treatment system ○​ Needs little mechanical maintenance Figure 8. Oxygen depletion curve ​ Disadvantages ○​ High Cost Table 2. Yellow Line Zones. ○​ Requires piped water YELLOW LINE: Dissolved Oxygen ○​ Requires permeable subsoil structure The oxygen sag curve indicates the amount of oxygen in ○​ Effluent can contaminate ground or surface water every point of the body of water. ○​ Space for drainage field is required CLEAN ZONE National Building Code ​ Optimum level of dissolved oxygen ​ Tropical countries like the Philippines have an optimum level of 7 mg/L of dissolved O2 CLEAN ZONE TO DECOMPOSITION ZONE ​ Organic loading → decrease dissolved oxygen ​ Wastewater with organic matter is discharged into the body of water ​ Biologically dead river: Too much organic loading → oxygen level would no longer be able to recover (flat yellow line) → Only anaerobic organisms will survive ​ Possible Mechanisms: 1.​ Organic matter contains carbon atoms, which serves as food for microorganisms. Microorganisms Figure 7. Wrong vs Correct Septic Tank will go to the source, break down the carbon organic matter, and simultaneously utilize oxygen. ​ WRONG SEPTIC TANK 2.​ Carbon atoms bond with available oxygen in water, ○​ Liquid component of waste will flow towards the resulting in its decomposition leaching chamber TOWARDS THE RECOVERY ZONE ○​ Water can seep into the groundwater which can contaminate tap water ​ Turbulence would speed up the process of aeration (disturbs water) ​ CORRECT SEPTIC TANK ​ O2 content may recover when the river self-purifies ○​ Septic tanks must be water-tight ​ Unwanted gases like CO2 would escape into the ​ Cemented to prevent water from seeping into the atmosphere ground ○​ CO2 is formed from the aerobic decomposition of ○​ When there is displacement, water will be discharged organic matter into the drainage canal or sewage system where it will ​ O2 from the atmosphere will enter the body of water undergo treatment until it reaches the state of equilibrium ​ The quality of effluent must be EQUAL or BETTER than Table 3. Blue Line Zones. the quality of the receiving body of water. BLUE LINE: Biological Oxygen Demand (BOD) Amount of oxygen needed to stabilize organic matter. CLEAN ZONE ​ No organic matter present: 0 BOD PH 136 | Excreta Disposal 3 of 12 CLEAN ZONE TO DECOMPOSITION ZONE ​ 0.000005 ppm of polychlorinated biphenyls (PCB) is almost negligible, but once it enters into and goes up the ​ Organic loading → Higher level of pollution food chain, the concentration of heavy metals (PCB) ​ Increased BOD also increases Depletion of O2 Due to Untreated Water ○​ Phytoplankton → Zooplankton → Small fish (5-6 ppm) ​ Untreated wastewater contains urine and feces → Lake trout (10-20 ppm) ​ Once urea is discharged into a body of water, it will utilize ○​ Heavy metals CANNOT be destroyed, they only oxygen for it to be transformed into ammonia accumulate ​ Ammonia will need oxygen (4.5 mg of dissolved O2 per ​ If man eats contaminated fish, some heavy metals will liter) to be converted into nitrate (NO2) enter our system, which may remain there OR be ○​ More oxygen is needed to stabilize nitrate, leaving little discharged back through our excreta to no oxygen for aquatic organisms in the body of ​ The continued consumption of contaminated fish water increases the concentration of heavy metals in our system, ​ This leads to oxygen depletion → fish kills leading to chronic effects ​ Vegetables surviving in bodies of water may absorb heavy EUTROPHICATION metals via their roots and remain stored in their leaves ​ Process of enriching bodies of water with NPK ​ Snails found in the water used as feed for ducks may also ​ Green arrows in the figure below show possible sources transfer these heavy metals into duck eggs ○​ Even treated wastewater can still contain NPK DISEASES ​ If there is too much nutrients in the water, algae will have an abundant supply of food → algal bloom ​ Caused by the presence of pathogens ​ Water-related diseases can be classified into four major categories: 1.​ Water-Borne Diseases ​ Caused by ingesting contaminated water ​ Examples: ○​ Chemicals: Methemoglobinemia ○​ Pathogens: cholera, botulism, typhoid, hepatitis A, dysentery, cryptosporidiosis ○​ Mercury can cause minamata diseases 2.​ Water-Washed Diseases ​ Caused by the unavailability of water ​ Due to unavailability of uncontaminated water, one is Figure 9. Eutrophication deprived of a clean water supply and cannot practice personal hygiene 1.​ DURING THE DAY: algae will go to the water surface for ​ e.g. trachoma, enterobiasis, ascariasis, photosynthesis trichomoniasis, trichuriasis, pediculosis/scabies ○​ CO2 + H2O + Solar Energy = Glucose + O2 ○​ Use glucose for growth and development 3.​ Water-Based Diseases ○​ O2 is NOT needed by the plants; excess will be ​ Caused by parasites that live in the water released in water → increasing pH (>9) → basic water ​ As waste is discharged into water, some parasites 2.​ AT NIGHT: some algae will die may survive and cause diseases ○​ Algae will use some of the O2 and respire CO2, ​ e.g. schistosomiasis, clonorchiasis, fasciolopsiasis decreasing pH → acidic water 4.​ Water-Borne Diseases 3.​ Water is basic during the day and acidic at night. ​ Caused by vectors that breed in or bite near bodies of 4.​ Some aquatic organisms cannot adapt to the rapid or water abrupt fluctuation of pH, leading to fish kills. ​ e.g. malaria, filariasis 5.​ SUMMARY: Eutrophication → Algal Bloom → Fish Kills ACCUMULATION ​ Bioaccumulation ○​ Increase in the concentration of a pollutant from the environment to the first organism in a food chain ​ Biomagnification ○​ Increase in the concentration of a pollutant from one link in a food chain to another ○​ The first point of entry into the food chain Figure 11. Mode of transmission of excreta transmitted diseases. ​ Once diseased individuals and carriers discharge their excreta that might contain pathogenic organisms (i.e. bacteria, viruses, parasites), and they are not properly disposed of, then the excreta may: ○​ Contaminate the water and soil; ○​ Allow arthropods to come in contact with them; or ○​ Be accidentally touched by hands ​ These four factors may contaminate food, or make contact with a susceptible individual who may also ingest the contaminated food Figure 10. Bioaccumulation PH 136 | Excreta Disposal 4 of 12 ​ This can be prevented by providing: Category V ○​ Sanitary facilities (toilets) to prevent the possible ​ Organisms that are latent, persistent, able to multiple, contamination of the water and soil, and prevent the with one or more intermediate aquatic hosts contact of vectors with excreta ​ Include all water-based helminths: schistosomiasis, ○​ Water supply to prevent contamination of hands clonorchiasis, and fasciolopsiasis through proper hygiene ○​ Unlike Category III, Category V needs water to TRANSMISSION AND CLASSIFICATIONS survive ​ Transmission foci: contaminated water ​ Transmission of an excreted infection and the ​ Control measures include: classifications of excreta-related diseases depend on the ○​ Category III control measures following: ○​ Control of snails ○​ Excreted Load: concentration, volume, or ○​ Cooking fish and aquatic vegetation characteristics of excreta ○​ Characteristics of Organisms Present in Excreta: Category VI ​ Latency: will it be able to cause infection ​ Insect-related diseases immediately or will it develop first? ​ Diseases transmitted by mosquitoes which preferentially ​ Persistence: how long will it survive in the breed in polluted water environment? ​ Control: Provision of toilets ​ Multiplication: can it multiply? ○​ Infective Dose: how much must be ingested to cause Table 4. Health Impacts of Sanitation Improvements. infection? PERSONAL ○​ Susceptibility of host SANITATION CATEGORY HYGIENE ALONE ALONE Category I I Slight-moderate Great ​ Organisms that are non-latent, unable to multiply, and Moderate- II Great have a low infective dose great ​ Include viruses, protozoa, enterobius, hymenolepis III Great Moderate ​ Transmission foci: domestic and personal IV Great Negligible contamination V Great Negligible ​ Control measures include improving domestic water VI Great Negligible supply, health education, and housing (e.g. indoor air Categories I-II: Mainly water (personal hygiene) Categories III-IV: Mainly provision of sanitation (sanitary facilities) quality) Category II HEALTH IMPACTS ​ Organisms that are non-latent, medium to high ​ The presence of different impurities in wastewater may infective dose, moderately persistent, and able to lead to the following impacts: multiply ○​ Solids ​ Include all bacteria ​ Turbidity ​ Transmission foci: Category I + water and crop ○​ Organic matter contamination ​ Oxygen depletion ​ Control: Category I + effective water treatment prior to ○​ Presence of nutrients (eutrophication) discharge or reuse of excreta ​ Algal bloom ​ Fish kills Category III ○​ Inorganic chemical accumulation ​ Organisms that are latent, very persistent, no ​ Bioaccumulation multiplication, and no intermediate host ​ Magnification ​ Include geohelminths: ascaris, trichuris, hookworm, ○​ Presence of pathogenic organisms strongyloides ​ Water-related diseases ○​ Eggs must be discharged unto the soil for them to ​ Excreta-related diseases develop EXCRETA DISPOSAL FACILITY ○​ They cannot mature if they are discharged into water ​ Transmission foci: yard, field, and crop contamination ​ Purpose of sanitation: to contain and process human ​ Control measures include: wastes until they or their end products are safe enough for ○​ Treatment before land application release into the environment ○​ Provision of toilets ​ A toilet should be able to: ○​ Control odor and prevent the ingress or egress of Category IV disease vectors ​ Organisms that latent, persistent, with intermediate ○​ Prevent the release of feces and wastewater into the host environment before it is safe to do so ​ Include T. saginata (cow) and T. solium (pig) GENERAL CONSIDERATIONS IN DISPOSAL OF EXCRETA ​ Transmission foci: Yard, field and fodder (grass) contamination 1.​ Wastes must not contaminate any drinking water supply. ○​ If excreta comes into contact with these materials, 2.​ They must not give rise to a public health hazard by being they may be accidentally eaten by cows or pigs accessible to insects, rodents, or other possible vectors ​ Control measures include: which may come into contact with food or drinking water. ○​ Category III control measures 3.​ They must not give rise to public health hazards by being ○​ Thorough cooking (especially for meat-eaters) accessible to children. ○​ Meat inspection PH 136 | Excreta Disposal 5 of 12 4.​ They must not violate laws or regulations governing Overhung Latrine water pollution or sewage disposal. ​ Allow disposed excreta to fall directly into bodies of water 5.​ They must not pollute or contaminate the waters of any ○​ Has a slit where one can squat and discharge their bathing beach, shellfish-breeding ground, or stream used waste for public or domestic water-supply purposes, or for recreational purposes. Conventional Pit Latrine 6.​ They must not give rise to a nuisance due to odor or unsightly appearance. EXCRETA DISPOSAL FACILITY ​ Sanitation facilities should: ○​ Be affordable and maintain ○​ Provide privacy to users Figure 13. Conventional pit latrine (L), Conventional pit latrine in mountain areas without water (M), Conventional pit latrine near bodies of water ○​ Provide convenience (R) ○​ Confer status to them ​ Common toilet facility in remote rural areas ○​ In some cases, allow safe recovery of the resources ○​ Appropriate for areas where water is a problem such as soil ameliorants, animal feed, and energy ○​ Consists of a pit, squatting plate, foundation, and contained in the waste structure CULTURAL ACCEPTABILITY ​ Disadvantages include: ○​ Smells bad ​ Sanitation facilities should also be culturally ○​ Breeding areas for insects acceptable to users in terms of: ○​ Children may be afraid of falling into the pit ○​ Defecating position ○​ Type of anal cleansing material used SANITARY SYSTEMS (ONSITE SANITATION) ○​ Practices and taboos on using and handling wastes ​ Its disposal technology may either be the dry on plot ○​ Light and ventilation technology or wet system ○​ Location of the facility relative to the house and its ​ Ventilated Improved Pit (VIP) - uses dry on plot technology orientation must be considered ​ Wet Pit with Pour-Flush Bowl ​ Composting Toilets SANITATION SYSTEMS & TECHNOLOGIES ○​ Pour-flush Toilet with Septic Tank and On-site ​ Point of Disposal: generation (where waste was disposed) Disposal ○​ Onsite sanitation: unsanitary and sanitary systems ○​ Conventional Septic Tank ○​ Offsite sanitation ○​ Biogas Toilets ​ System of Disposal: use of water (wet or dry) ○​ Wet System Technologies Ventilated Improved Pit Latrine ○​ Dry on Plot Technologies ​ Important actions in the pit: ONSITE SANITATION ○​ Liquid portion of excreta seeps into the soil ○​ Solids are broken to simpler compounds by biological ​ The unsanitary systems discussed include the open pit digestion latrine, overhung latrine, and conventional pit latrine ○​ Water is used only for hand washing or floor cleaning ​ The sanitary systems discussed include ventilated ​ Mechanism: improved pit latrine, wet pit with pour-flush bowl, and ○​ The vent pipe allows the generated gasses inside the composting toilets pit to escape ○​ It is often placed higher than the roof to prevent the UNSANITARY SYSTEMS (ONSITE SANITATION) airdropping of wind ​ Open defecation but restricted to a community-designated ○​ The shoot is relatively bigger, which prevents clogging area and allows the use of anal cleansing materials, which ​ Unimproved pit (e.g. Antipolo) lengthens the lifespan of the pit ​ Overhang over a watercourse, pigpen, or fish pond ​ Both the ventilated improved pit (VIP) toilet and ventilated improved double pit (VIDP) toilet use the dry on plot Open Pit Latrine technology (refer to Figure 13) Dry on Plot Technologies Figure 12. Pit Latrine ​ Has disadvantages > advantages, but is still a common facility used in the province: ○​ Open (i.e. no privacy) ○​ Groundwater will be contaminated with excreta ○​ Uncomfortable for users Figure 13. Dry on plot technologies: ventilated improved pit (L), ventilated improved double pit toilet (R) PH 136 | Excreta Disposal 6 of 12  ​ Narrow opening does not allow the use of bulky anal cleansing materials which may cause clogs Figure 14. Dry on plot technologies: composting/urine diversion toilet (L) and aqua-privy and soakaway (R) Wet System Technologies Figure 18. Trap seal Cistern Flush Toilets Figure 18. Cistern Flush Toilet Figure 15. Wet system: pour-flush toilet (L) and conservancy tank (R) ​ Used in areas with continuous supply of water or water districts such as Metro Manila Pour-Flush Toilets ​ Direct discharge into sewage systems or septic tanks ​ Uses the wet system technology (refer to Figure 15) ​ Advantages: ○​ Inexpensive ○​ Long-term solution ○​ Uses low volume water ○​ Can be upgraded to connect to sewer ○​ Minimal odor, insect, and fly breeding ○​ In-house location Figure 19. Septic Tank Figure 16. Pour-flush toilets in rural areas and provinces Figure 20. Septic Tank mechanism ​ Vent pipe regulates air pressure ​ Solids accumulate ​ Almost 95% effective in removing solids ​ When full, experts are called for dislodging OFFSITE SANITATION ​ Cartage Feces ○​ Transport feces from origin to disposal site ​ Sewerage (to treatment facility) Figure 17. Trap seal ○​ Once waste is flushed, it is discharged immediately in ​ TRAP SEAL: refers to the water being held in the bent the sewer or septic tanks → treatment facility or septic portion of a fixture trap tank ○​ Forms a seal against the passage of sewer gases ○​ Conventional Sewerage through the trap and into the building ○​ Shallow Sewerage ○​ Prevents the entry of unwanted gasses and insects Septic tanks connected to small-bore sewerage PH 136 | Excreta Disposal 7 of 12  SEWAGE TREATMENT FACILITY STEP 1: Anaerobic Ponds SEWERAGE AND SEWAGE DISPOSAL ​ Sewage disposal applies to the act of getting rid of sewage by any method. ​ It may be done with or without previous treatment of the sewage. BIOLOGICAL TREATMENT Figure 24. Anaerobic Pond ​ Deepest among the three types ○​ Must be devoid of oxygen to maximize removal of organic matter ○​ Water stays for 32 days ​ When water enters the pond, solids, heavy metals and some microorganisms settle at the bottom, forming a sludge, and undergoes anaerobic decomposition Figure 21. Activated Sludge Treatment Process ○​ Biological Oxygen Demand (BOD) is then lost as gas ​ Screening and sedimentation like methane, CO2 and H2S ​ Biological treatment ​ Secondary treatment STEP 2: Facultative Ponds ​ Solid Processing ​ Water will flow from Anaerobic pond ​ Filtration and disinfection ​ Stays for 11 days ​ There are two layers: WASTE STABILIZATION BONDS ○​ Aerobic layer ​ Natural way of treating wastewater biologically ​ Symbiotic relationship of algae and bacteria ​ Organisms stabilize the organic matter present in ​ Removes solids, heavy metals, organic matter, wastewater and nutrients (only pathogen is left) ○​ Anaerobic layer Figure 22. Stabilization Ponds Figure 25. Facultative Pond STEP 3: Maturation Ponds ​ Water stays for 30 days (in Manila 6 days for Area 1.5 ha and depth 1.85 m) ​ Shallowest to make it fully aerobic form the bottom up to the surface ​ Targets fecal bacteria through Increased Pond Temperature, pH > 9, and Photo-oxidation Figure 23. Waste Stabilization Ponds Process ​ Anaerobic → Facultative → Maturation ponds Figure 26. Maturation Pond PH 136 | Excreta Disposal 8 of 12 Effluent Standards c.​ 7 mg/L d.​ 8 mg/L 6.​ Which of the following are not the correct way of building a septic tank? a.​ Septic tanks must be water-tight b.​ Liquid component of waste will flow towards the leaching chamber c.​ When there is displacement, water will be discharged into the drainage canal or sewage system d.​ They must prevent water from seeping into the ground 7.​ What category of disease contains organisms that are Figure 27. Effluent Standards latent, persistent, with intermediate hosts? ​ After water treatment, the water is discharged to a body of a.​ Category V water b.​ Category VI ​ Must comply with the DENR AO 2016-8 before being c.​ Category IV discharged into bodies of water d.​ Category III ​ Effluent quality must be determined to be equal or 8.​ True or False. Excreta must be accessible to insects, better than that of the receiving body of water rodents, or other possible vectors to not give rise to a public health hazard RESOURCE RECOVERY 9.​ Which of the following should sanitation facilities not ​ Aquaculture be: ○​ Treated water can be used for agriculture purposes a.​ Provide privacy to users ○​ Water containing algae (good for water the plants) b.​ Expensive to use and maintain may be used for irrigation purposes c.​ Provide convenience ​ Composting d.​ Confer status to the users ○​ The sludge can be collected and composted and be 10.​ Arrange the waste stabilization ponds based on used as soil conditioners increasing depth. a.​ Facultative -> Anaerobic -> Maturation REFERENCES b.​ Anaerobic -> Facultative -> Maturation ​ Lectures c.​ Maturation -> Facultative -> Anaerobic Quizon, R.R. (2025). Excreta Disposal Management d.​ Facultative -> Maturation -> Anaerobic REVIEW QUESTIONS 11.​ True or False. Effluent quality must be determined to be equal or lower quality than that of the receiving body of 1.​ Which of the following is NOT a major component of water human excretions? 12.​ Which of this is not an example of resource recovery in a.​ Nitrogen the waste treatment process? b.​ Phosphorus a.​ The use of water for watering plants c.​ Calcium d.​ Potassium b.​ Aquaculture c.​ Composting of sludge into soil conditioners 2.​ What happens when a septic tank is constructed in an d.​ None of the above area where the groundwater is very deep? a.​ Pollutants spread rapidly through the soil, contaminating nearby water sources b.​ Pollutants travel only 1 meter laterally and 3 meters vertically, preventing groundwater contamination c.​ Pollutants travel only 3 meters laterally and 1 meter vertically, preventing groundwater contamination d.​ None of the above 3.​ Why does the Department of Health (DOH) recommend constructing water sources at least 25 meters away from pollution sources? a.​ To avoid bacterial contamination, as bacterial pollutants travel up to 11 meters b.​ To prevent the spread of waterborne viruses c.​ To ensure complete chemical neutralization in the soil d.​ To comply with international sanitation standards 4.​ What is the process of enriching the bodies of water with Nitrogen, Phosphorus, and Potassium. a.​ Resource recovery b.​ Enrichment c.​ Turbidity d.​ Eutrophication 5.​ What is the optimum level of dissolved oxygen in the Philippines a.​ 7.5 mg/L b.​ 6 mg/L PH 136 | Excreta Disposal 9 of 12  APPENDICES Appendix A. Summary of classifications of excreta-related diseases. CLASSIFICATIONS OF EXCRETA-RELATED DISEASES CATEGORY I CATEGORY II CATEGORY III CATEGORY IV CATEGORY V CATEGORY VI ​ Non-latent ​ Non-latent ​ Latent ​ Latent ​ Latent ​ Insect-related ​ Unable to ​ able to ​ No ​ Persistent ​ Persistent diseases multiply multiply multiplication ​ With ​ Able to ​ Low infective ​ Medium to ​ Very persistent intermediate multiply Organism dose high infective ​ No host ​ With one or dose intermediate more ​ Moderately host intermediate persistent aquatic hosts ​ Domestic and ​ Category I ​ Yard ​ Yard ​ Contaminat ​ Polluted water personal measure ​ Field and crop ​ Field and ed water contamination ​ Water and contamination fodder Transmission crop foci contaminati contamination on ​ Improved: ​ Category I ​ Treatment ​ Category III ​ Category III ​ Provision of ○​ Domestic measure before land control control toilets water supply ​ Effective application measures measures Control ○​ Health water ​ Provision of ​ Cooking ​ Control of measure education treatment toilets ​ Meat snails ○​ Housing inspection ​ Cooking fish and aquatic vegetation ​ viruses ​ All bacteria ​ Geohelminths: ​ T. saginata ​ water-based ​ Vectors ​ protozoa ○​ ascaris (cow) helminths ○​ Mosquit ​ enterobius ○​ trichuris ​ T. solium (pig) ○​ schistoso oes ○​ hookworm miasis Example ​ hymenolepis ○​ strongyloid ○​ clonorchia es sis ○​ fasciolopsi asis Table 1. Human Excretions Composition. COMPONENTS OF HUMAN EXCRETIONS Urine Feces Total Fertilizer 230 kg cereal 30-50 L 30-50 L N 3.1-5.6 kg 0.09 kg 3.4-5.7 kg 5.6 kg P 0.24-0.4 kg 0.19 kg 0.36-0.6 kg 0.7 kg K 0.6-1.0 kg 0.17 kg 0.72-1.2 kg 1.2 kg Total NPK 94% 6% 4.5-7.5 kg 7.5 kg Pathogen 4 15 Table 4. Health Impacts of Sanitation Improvements. SANITATION CATEGORY PERSONAL HYGIENE ALONE ALONE I Slight-moderate Great II Great Moderate- great III Great Moderate IV Great Negligible V Great Negligible VI Great Negligible Categories I-II: Mainly water (personal hygiene) Categories III-IV: Mainly provision of sanitation (sanitary facilities) PH 136 | Excreta Disposal 10 of 12  Figure 1. Components of the environmental system. Figure 6. Top view of pollution movement. Figure 7. Wrong vs Correct Septic Tank. Figure 8. Oxygen depletion curve. PH 136 | Excreta Disposal 11 of 12  Figure 11. Mode of transmission of excreta transmitted diseases. Figure 11. Mode of transmission of excreta transmitted diseases. Figure 28. Effluent Standard. PH 136 | Excreta Disposal 12 of 12