Wastewater Characteristics and Reuse Applications
Wastewater Sources and Reuse
Wastewater Origins
Wastewater originates from various sources, including:
- Individual residences
- Residential complexes
- Public facilities
- Commercial establishments
- Industrial parks
- Community systems
Wastewater Reuse Methods
Several methods facilitate wastewater reuse:
- Constructed Wetlands: Free surface flow, subsurface flow
- Discharge to Water Bodies: Streams, lakes, ponds, oceans
- Vaporization Systems: Evapotranspiration beds, evapotranspiration lagoons
- Ground Application: Surface application, spray application, drip application
Reuse Applications
Reclaimed wastewater finds applications in:
- Agricultural irrigation
- Green area watering
- Aquifer recharge
- Natural wetlands restoration
- Non-potable water supply
- Industrial processes
- Recreational lakes
- Augmenting water supplies
Wastewater Characteristics
Soil Surface Provision
- Ground absorption systems
- Conventional infiltration fields
- Pressurized dosed shallow infiltration fields
- Shallow infiltration fields under pressure with sand beds
- Drip irrigation
- Infiltration beds
- Embankment infiltration systems
- Filling systems
- AT-like systems
Physical Characteristics
- Total solids
- Turbidity
- Color
- Transmittance
- Odor
- Temperature
- Density
- Conductivity
Inorganic Characteristics
- Ammonia
- Nitrogen
- Phosphorus
- pH
- Alkalinity
- Chlorides
- Sulfates
- Metals
- Specific compounds
- Gases
Functional Characteristics
- BOD (Biochemical Oxygen Demand)
- DBOu (Ultimate Biochemical Oxygen Demand)
- DON (Dissolved Organic Nitrogen)
- COD (Chemical Oxygen Demand)
- TOC (Total Organic Carbon)
- Specific compounds
Biological Characteristics
- Coliform organisms
- Specific microorganisms
- Toxicity
Key Wastewater Parameters
Solids
- Total Solids: Total mass of residue after evaporation per 1000 volume units of the sample.
- Volatile Total Solids: Mass of residue lost upon burning per 1000 volume units of the sample.
- Total Suspended Solids: Weight of residue after evaporating 1000 volume units of the sample.
- Volatile Suspended Solids: Mass of residue lost upon burning per 1000 volume units of the sample.
Turbidity
Turbidity measures the light-scattering properties of water, indicating the amount of light absorbed or scattered by suspended matter. It arises from clay, silt, or rock erosion, industrial waste, corrosion products, plant remains, and microorganisms. Detergents and soaps in wastewater also contribute to turbidity. Turbidity is measured by comparing scattered light intensity in a sample with a reference suspension, expressed in Nephelometric Turbidity Units (NTU).
Color
Color results from suspended solids, colloidal material, and dissolved substances. Apparent color is caused by suspended solids, while true color comes from dissolved and colloidal substances, determined in a filtered sample. Wastewater color is assessed by comparing it to potassium chloroplatinate (K2PtCl6) solutions, with one color unit equivalent to 1 mg/L of platinum. Infiltration, industrial discharges, and organic compound breakdown contribute to color. Humic substances from infiltration impart a yellow hue, while industrial discharges may introduce various colors due to dyes and metal compounds.
Odor
Odor is the sensation perceived by smell from volatile substances. Measurement involves diluting the water until odorless, expressed as the dilution giving detectable odor. Due to subjectivity, at least two individuals should perform the measurement, comparing it to deodorized water in an odor-free environment.
Temperature
Wastewater temperature typically exceeds supply water temperature due to hot water from domestic and industrial use. Temperature significantly influences biological wastewater treatment processes and affects chemical reactions, aquatic life, and water suitability.
Other Parameters
- Density: Essential for designing sedimentation tanks, constructed wetlands, and most treatment units.
- Transmittance: A liquid’s capacity to transmit light at a specific wavelength, defined as transmitted light intensity after passing through a solution of known thickness and initial intensity.
- pH: Measures hydrogen ion concentration, defined as the negative logarithm of hydrogen ion concentration.