Waste management

Agricultural waste

refers to waste generated from planting or harvesting of crops, trimming or pruning of plants and wastes or run-off materials from farms or fields

Agricultural solid waste

results from the production and processing of crops and animals or agricultural products, including manures with at least 20% solids, pruning and crop residues wherever produced

Agricultural liquid waste

consists of liquid waste and slurry resulting from the production of livestock and poultry; and processing of crops, livestock and poultry

Hazardous waste

solid waste or combination of solid wastes which because of its quantity, concentration, or physical, chemical or infectious characteristics may cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating

Waste

refers to manure with added bedding, hair, feather, rainwater, soil, etc.

Pollution

alteration of the physical, chemical and/or biological properties of any water and/or atmospheric air of the Philippines

Point Source

any identifiable source of pollution with specific point of discharge into a particular water body

Non-Point Source

any source of pollution not identifiable as point source to include, but not be limited to, runoff from irrigation or rainwater which picks up pollutants from farms and urban areas

Manure

accumulated moist animal excrement that does not undergo decomposition or drying; it include feces and urine which may be mixed with bedding material, spilled feed or soil

As excreted manure

refers to feces and urine prior to any changes due to dilution water addition, drying, volatilization, or other physical, chemical, or biological processes

Biochemical Oxygen Demand (BOD5)

quantity of oxygen needed to satisfy biochemical oxidation of organic matter in waste sample in 5 days at 20oC

Chemical Oxygen Demand (COD)

rapid laboratory procedure using chemical oxidants and heat to fully oxidize organic components of waste

Fixed solids

part of total solids remaining after volatile gases is driven off at 600oC

Volatile solids

part of total solids driven off as volatile gases when heated to 600oC

Suspended solids

solids removed by filtration

Dissolved solids

part of total solids passing through the filter in a filtration procedure

Total solids

residue remaining after water is removed from waste material by evaporation

Settleable solids

solids in suspension that will settle under quiescent conditions due to the effects of gravity

Methane (CH4)

flammable and explosive gas released from livestock, agricultural practices, and the decomposition of organic waste. It poses risks in confined spaces due to its asphyxiant properties.

Carbon Dioxide (CO2)

colorless, odorless asphyxiant gas heavier than air, produced in anaerobic environments. It can displace oxygen in confined spaces, causing suffocation, and is naturally sequestered by plants during photosynthesis.

Ammonia (NH3)

sharp, pungent gas produced from the decomposition of animal waste due to inefficient nitrogen conversion. It is an irritant that can cause eye and respiratory tract irritation and, at high concentrations, asphyxiation

Hydrogen sulfide (H2S)

toxic, flammable gas with a rotten egg odor, produced during anaerobic digestion. It is highly poisonous and can cause dizziness, unconsciousness, or death at high concentrations.

Liquid

manure consistency; MC > 96%; treated just like water

Slurry

manure consistency; 90%96%; requires special handling for solids

Semi-solid

manure consistency; 80%90%; has liquid and solid properties

Solid

manure consistency; MC≤80%; never acts like a liquid

Emission

any air contaminant, pollutant, gas stream or unwanted sound from a known source which is passed into the atmosphere

Greenhouse gases

gases that can potentially or can reasonably be expected to induce global warming

Contamination

means the introduction of substances not found in the natural composition of water that make the water less desirable or unfit for intended use

Pollutant

refers to any substance—solid, liquid, gaseous, or radioactive—that, when introduced into the environment, can cause harm, contamination, or undesirable effects on ecosystems, human health, or natural resources.

Sewage

waterborne human or animal wastes, excluding oil or oil wastes, removed from residences, buildings, institutions, industrial and commercial establishments

Wastewater

waste in liquid state containing pollutants

Water quality

means the characteristics of water which define its use in terms of physical, chemical, biological, bacteriological or radiological characteristics by which the acceptability of water is evaluated

Agricultural waste management system

planned system in which all necessary components are installed and managed to control and use byproducts of agricultural production in a manner that sustains or enhances the quality of air, water, soil, plant, and animal resources

Total System Approach

accounts for all the waste associated with an agricultural enterprise throughout the year from production to utilization; management of all waste, all the time, all the way

Alleys

paved areas where the animals walk. They generally are arranged in straight lines between animal feeding and bedding areas. On slatted floors, animal hoofs work the manure through the slats into these paved areas located below, and the manure is collected by flushing or scraping these areas

Scrape alley

manure collection area designed for livestock facilities where manure is mechanically scraped and removed. For dairy and beef cattle, these alleys should be 2.5–4 m wide, while for swine and poultry, they should be 1–2.5 m wide

Flush alley

manure collection area where water is used to flush manure to a collection or treatment point. The alley width ranges from 1–3 m, depending on the animal type. Initial flow depth should be 75 mm for underslat alleys and 100–150 mm for open alleys, with a grade of 1.25%–5% for efficient flushing

Gutter

narrow trenches used to collect manure and bedding. They are often employed in confined stall or stanchion dairy barns and in some swine facilities

Gravity drain gutter

These gutters are designed for swine buildings to rely on gravity for manure flow, minimizing mechanical intervention. They are particularly effective in areas where manure naturally flows towards a collection drain. Minimum depth of 760 mm, width of 150 mm, and a bottom slope of 1% toward the drain to ensure continuous flow.

Step-dam gutter

Commonly used in cattle barns, this gutter system collects manure in flat-bottomed channels where dams hold it back temporarily before allowing it to flow into deeper cross-channels. This design helps manage manure in facilities with larger animals. These are 150 mm high dams, a gutter width of 760 mm, and step-down sections leading to deeper channels for effective waste movement

Scrape gutter

Ideal for confined stall barns, these gutters are designed to be manually or mechanically scraped. Paddles move the manure forward, making it suitable for barns with limited drainage or flat areas. Width of 0.4–0.6 m, depth of 0.3–0.4 m, with a generally flat bottom (0% slope) and paddles to push manure along the gutter.

Flush gutter

These gutters use water to flush manure to a collection point, making them ideal for facilities that prioritize cleanliness and automation. The system relies on flushing tanks or pumps to clean the gutters efficiently. Minimum depth of 0.6 m at the shallow end, with depth either constant or increasing along its length. Bottom slope ranges from 0–5%, depending on storage and cleaning needs.

Reception pits

structures designed to collect slurry and liquid waste from scraping, gravity flow, or flushing systems, serving as temporary storage before further treatment or disposal. The pits are designed to hold waste for several days, and the waste is removed either by gravity or pumps.

Gravity Flow Pipes

transport liquid and slurry manure using elevation differences, minimizing the need for mechanical pumping. These systems use pipes with diameters ranging from 18 to 36 inches and require slopes of 4–15%, with 7–8% being the preferred slope for optimal performance

Push-Off Ramps

used to load manure scraped from open lots into spreaders or storage facilities efficiently and safely. They feature ramp slopes not exceeding 5% and have safety restraints at each end to prevent tractors from accidentally going off the ramp.

Screening

physical treatment of wastewater, first unit operation in all wastewater treatment plants with the main purpose of removing solid materials that could cause damage to other process equipment. It separates solids by trapping them on a screen that permits liquids and small particles to pass through.

Sedimentation/ Settling

physical treatment of wastewater, a process used in both primary and secondary wastewater treatment, that takes place when gravity pulls particles to the bottom of a tank

Flotation

physical treatment of wastewater, a process which increases the rate of removal of suspended matter from liquid wastes. It uses methods of air injection in such a way that small air bubbles (<0.1mm) should be formed. The process achieves solids-liquid separation by attachment of gas bubbles to suspend particles, reducing the effective specific gravity of the particles to less than that of water.

Coagulation

chemical treatment of wastewater wherein the addition of chemical such as alum, which produces positive charges to neutralize the negative charges on the particles, then the particles, can stick together,forming larger particles, which are more easily removed

Disinfection

chemical treatment of wastewater wherein its purpose is to reduce the total bacterial concentration and to eliminate the pathogenic bacteria in water

Adsorption

chemical treatment of wastewater, a process in which atoms, ions, or molecules (adsorbates) from a gas, liquid, or solution medium adhere to the surface of an adsorbent material, such as activated carbon. This process is facilitated by the high internal surface area of adsorbents, making them particularly effective for removing polar compounds

Precipitation

chemical treatment of wastewater, which is a process in which a solid forms from a solution during a chemical reaction. In chemical precipitation, ionic constituents are removed from water by adding counter-ions that reduce the solubility of the dissolved substances, causing them to form solid particles that can be separated from the liquid.

Anoxic process

biological treatment of wastewater used for the removal of nitrogen from wastewater, occurring under conditions where molecular oxygen is absent but nitrite or nitrate is present. In this environment, specific bacteria convert nitrate or nitrite into nitrogen gas. This process is primarily applied for the removal of carbonaceous organic matter, nitrification (conversion of ammonia to nitrate), denitrification (conversion of nitrate to nitrogen gas), phosphorus removal, and waste stabilization

Nitrification

biological process by which ammonia is first converted to nitrite and then to nitrate

Denitrification

biological process by which nitrate is converted to nitrogen and other gaseous end products

Biological Oxygen Demand (BOD)

traditional and most widely used test to measure the concentration of organic matter in wastewater. It is based on the principle that, if sufficient oxygen is available, aerobic biological decomposition by microorganisms will continue until all organic waste is consumed.

Dissolved Oxygen

measures the concentration of oxygen dissolved in a water or wastewater sample. It is commonly performed using an electronic meter equipped with a specialized probe, which provides real-time measurements of oxygen levels in the sample.

Chemical Oxygen Demand (COD)

uses a chemical reagent (potassium dichromate in a 50% sulfuric acid solution) to oxidize both organic and inorganic substances in the sample. As a result, the concentration is typically higher than the BOD concentration for the same wastewater sample, since BOD only measures the consumption of organic compounds

Facultative Ponds

ponds which have aerobic conditions in the upper layers and anaerobic processes occurring in the bottom layers, especially in the settled solids. The ponds are usually called oxidation ponds or waste stabilization lagoons

Aerobic Ponds

pond where the organic matter is decomposed solely through aerobic oxidation with the oxygen obtained by mixing and photosynthesis. These ponds are designed with a large area to volume ratio. Oxygen is introduced by liquid recirculation, wind, or mechanical mixing and by photosynthesis.

Anaerobic Ponds

ponds in which the concentration of organic wastes applied per unit area is sufficient to bring about complete depletion of dissolved oxygen by limiting photosynthesis, by high bacterial oxygen demand, or both. These ponds are deep, have small surface area to volume ratio.

Aerated Lagoons

biological treatment units in which the oxygen demand is met by mechanical aeration equipment. The continuous oxygen supply permits the aerated lagoon to treat more waste water per unit volume per day

Hydrolysis

waste materials of plant and animal origins, which consist mainly of carbohydrates, lipids, proteins, and inorganic materials are solubilized into simpler ones with the help of extracellular enzyme released by the bacteria

Acidification

monomer such as glucose, which is produced in hydrolysis, is fermented under anaerobic condition into various acids with the help of enzymes produced by the acid forming bacteria. At this stage, the acid-forming bacteria break down molecules of six atoms of carbon into molecules of less atoms of carbon, which are in more reduced state. The principal acids produced in this process are acetic acid, propionic acid, butyric acid and ethanol.

Methanization

the principal acids produced in acidification, such as acetic acid, propionic acid, and butyric acid, are further processed by methanogenic bacteria. These bacteria convert the acids into methane (CH4) and carbon dioxide (CO2)

Composting

aerobic biological decomposition of organic matter. It is a natural process that is enhanced and accelerated by the mixing of organic waste with other ingredients in a prescribed manner for optimum microbial growth

Windrow

composting method wherein the arrangement of compost mix are in long, narrow piles. To maintain an aerobic condition, the compost mixture must be periodically turned.

Static pile

composting method which consists of mixing the compost material and then stacking the mix on perforated plastic pipe or tubing through which air is drawn or forced.

In-vessel

composting method which involves the mixing of manure or other organic waste with a bulking agent in a reactor, building, container, or vessel and may involve the addition of a controlled amount of air over a specific detention time

Gasification

process of converting organic materials into gas through either biological or physical processes. This transformation typically involves heating the materials in a controlled environment, where they react with limited oxygen or steam to produce a synthesis gas (syngas) composed of carbon monoxide, hydrogen, and carbon dioxide.

Pyrolysis

thermal decomposition of biomass that occurs in the absence of oxygen, typically at temperatures between 300-650°C.

Slow pyrolysis

type of pyrolysis that primarily produces char through carbonization

Rapid/Fast pyrolysis

type of pyrolysis mainly produces bio-oil or syngas

Torrefaction

process similar to pyrolysis but takes place at lower temperatures, around 200-320°C. It is mainly used as a pre-treatment for biomass to improve its energy density by drying and removing moisture

Bioethanol

form of renewable energy produced from agricultural feedstock, such as sugarcane, corn, or other biomass. As it is entirely derived from biological materials, its combustion generates cleaner emissions, primarily carbon dioxide, steam, and heat

Hydrolysis

process of breaking down cellulose into simple sugars using acids or enzymes, serving as a crucial step in converting biomass into fermentable sugars

Fermentation

biological conversion of sugars into alcohol through anaerobic respiration by microbes, such as yeast, resulting in the production of ethanol

Distillation

separation process that exploits differences in boiling points of substances in a mixture. For example, in ethanol production, ethanol, having a lower boiling point than water, evaporates first, allowing for its separation and purification