TSS means Total Suspended Solids, or particles that remain suspended in the water stream. TDS means dissolved solids, including salts, minerals, metals, and other ions that remain in solution. In WTP, RO, cooling tower, boiler, and wastewater systems, TSS represents the solids, sludge, biomass, or sediment load that must be removed.
PT Beta Pramesti Asia, through beta.co.id, helps industrial plants in Indonesia connect TSS and TDS data to the correct treatment path. High TSS normally calls for settling, media filtration such as sand silica, coagulants, flocculants, DAF, or ultrafiltration. High TDS instead points toward brackish water reverse osmosis, demineralizers, or ion exchange resin.
Last technically reviewed: 10 August 2026.
TDS and TSS may both be reported in mg/L, but they are not interchangeable. Indonesia’s SNI 6989.27:2019 covers the gravimetric TDS method, while SNI 6989.3:2019 covers gravimetric TSS. A handheld conductivity conversion is useful for dissolved-ion trends, but it does not replace a gravimetric TDS result when a design, contract, or compliance decision specifies the laboratory method.
| Parameter | What the result represents | Interpretation error to avoid |
|---|---|---|
| TDS | Dissolved residue that passes the method’s separation step | Treating a conductivity-derived meter value as identical to laboratory TDS |
| TSS | Suspended residue retained during the filtration step | Assuming coloured water must have high TSS without a test result |
| Turbidity | Light scattering caused by particles in the sample | Converting NTU directly to mg/L TSS without a water-specific correlation |
| Conductivity | The water’s ability to carry current because of dissolved ions | Assuming conductivity identifies a specific ion or hazard |
How Should a Plant Respond to a TSS Spike?
A TSS spike does not automatically justify a higher coagulant dose. First verify the sample, flow for the same interval, solids source, clarifier or DAF condition, sludge recycle, and upstream process changes. Once the causes are separated, the response can address hydraulic control, chemistry, filtration, or sludge handling instead of masking the problem with an untested setpoint change.
| Observed signal | Evidence to confirm | Diagnostic direction | Controlled response |
|---|---|---|---|
| One TSS result spikes while turbidity and the process remain stable | Point, time, container, preservation, method, duplicate, and sampling condition | The sample or result may not represent the process | Repeat sampling under the procedure before changing a setpoint |
| TSS and flow rise together | TSS and flow for the same interval, stream source, equalisation level, and production history | Solids load has increased, not only concentration | Calculate kg/day, equalise the load where possible, then check separation capacity |
| Outlet TSS rises as the sludge blanket changes | Blanket, RAS/WAS or recycle, overflow rate, settling test, and skimmer condition | Clarifier, DAF, or sludge-management upset | Stabilise the separation unit before blaming the chemistry |
| Floc is small or breaks readily | pH, alkalinity, actual dose, pump output, mixing energy, and a fresh jar test | Water chemistry, feed accuracy, or shear has changed | Change one variable in a controlled trial and compare it with the baseline |
| TSS rises after a raw-material change or washdown | Event timing, solids source, oil/grease, COD, pH, and particle-size distribution | Upstream load or solids character has changed | Segregate the stream where needed and retest coagulation, DAF, or filtration |
How to Convert TSS mg/L into a Solids Load
TSS concentration alone is not enough to size a treatment unit or sludge-handling system. Calculate the solids load as TSS (mg/L) × flow (m³/day) ÷ 1,000 = kg TSS/day. As a worked example, a 1,000 m³/day stream at 300 mg/L TSS carries approximately 300 kg of suspended solids per day.
The daily load helps buyers compare a clarifier, DAF, filtration, and sludge handling on the same basis. Two streams at 300 mg/L TSS may need different equipment when their flow, solids characteristics, oil and grease, or peak-load pattern differs, so report concentration and flow for the same sampling period. If the solids source is not clear, start with the liquid-waste source map so each drain, batch, and abnormal stream has an identity before the load is calculated.
TSS response limits for proposals and operation
TSS response limits should connect a laboratory number to an auditable decision. Use the design basis, permit, or contract as the final boundary; the table below separates data validation, separation capacity, chemical use, and sludge routing before equipment is selected.
| Decision level | Minimum data | Question answered | Technical handoff |
|---|---|---|---|
| Initial screening | TSS, turbidity, pH, average/peak flow, solids source | Is the main load suspended solids or dissolved ions? | Screen a clarifier, DAF, media filter, or membrane step |
| Separation testing | Jar test, settling test, flotation, oil/grease, floc size | Will the solids settle, float, or require coagulation-flocculation? | Match coagulants, flocculants, and the separation unit |
| Sludge balance | kg TSS/day, captured fraction, sludge solids, operating hours | How much mass reaches thickening, screw press, filter press, or disposal? | Check sludge-treatment capacity and haulage cost |
| Effluent verification | Outlet TSS, outlet flow, shift variation, test method | Does the result meet the process target or applicable discharge limit? | Set sampling frequency, alarms, and corrective actions |
Definition of TDS (Total Dissolved Solids)
Total Dissolved Solids, or TDS, is a term that refers to the concentration of all solids dissolved in water. This includes various minerals, salts, metals, as well as organic and inorganic ions. TDS not only gives an idea of the chemical composition of water but also affects physical properties such as taste, clarity, and even the electrical conductivity of water. High TDS levels are often associated with hard water which may have a less pleasant taste and could have a negative impact on health if it contains harmful contaminants.
As an indicator of water quality, TDS is critical in a variety of applications, from drinking water quality monitoring to industrial applications such as in boilers and cooling systems, where water quality must be maintained to avoid corrosion and scale buildup. Measuring TDS is an important step to assess the suitability of water for a particular use, and can also be an indication of the presence of chemical pollution in the water source.
Managing TDS levels is not only important for health and safety but also for the continued operation of industries that rely on water as a critical component of their processes. Therefore, a good understanding of what TDS is and how it affects various aspects of water use is important in the effective and responsible management of water resources.
Definition of TSS (Total Suspended Solids)
Total Suspended Solids (TSS) is a term used to describe particles that are not dissolved in water, but can be seen floating or suspended in the water column. These particles include a variety of materials such as dust, microorganisms, plankton, and other particles that often come from soil erosion as well as industrial waste. TSS is an important factor affecting the clarity and aesthetic quality of water sources, and has a significant impact on the health of aquatic ecosystems.
TSS particles can cause several environmental and health problems if not managed properly. In natural environments, the presence of high suspended particles can reduce the penetration of sunlight into the water, disrupting the photosynthesis process of aquatic plants and inhibiting their growth. In addition, these particles can clog fish gills, affect aquatic fauna, and lead to an overall decrease in habitat quality.
TSS monitoring is a critical component of water resources management, especially in areas with intense industrial activity. Effective monitoring methods can help identify sources of suspended particles and implement appropriate control measures to reduce pollution and maintain water quality. Regular monitoring of TSS is also important to ensure that water meets the quality standards set for specific uses, such as drinking water treatment or industrial water.
Differences and Relationship Between TDS and TSS in Water Quality Management
In water resources management, Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) are two key parameters often measured to assess water quality, although they measure very different aspects of water. TDS refers to all dissolved substances that cannot be seen with the naked eye, including minerals, salts, and metals, which help determine the hardness and mineral quality of water. Meanwhile, TSS refers to particles suspended in water, such as dust, plankton, and sediment, which can be identified visually or through the use of measurement tools.
How TDS and TSS Affect Each Other
Although TDS and TSS measure different components, they affect each other in aquatic ecosystems. For example, when TSS particles degrade or break down-either naturally through biological processes or through chemical or physical intervention-they can turn into solutes that then become part of TDS. This process can occur in natural waters, such as rivers and lakes, as well as in water treatment systems. The increase in TDS due to TSS decomposition can affect not only the taste and aesthetics of water, but also the safety of its use for domestic and industrial purposes.
The Importance of Understanding These Two Parameters
Understanding the differences and relationships between TDS and TSS is essential for effective and responsible water resources management. With proper monitoring and management of these two parameters, water resource managers can ensure that water meets the quality standards required for a particular use, be it for human consumption, industrial activities or the maintenance of aquatic life. Careful management of TDS and TSS not only safeguards public health and safety but also helps in maintaining environmental sustainability.
Management and Control of TDS and TSS
Controlling Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) levels in water is a crucial step, especially in the context of wastewater treatment and process-water supply. These management practices are not only essential to meet regulatory standards, but also to protect operating reliability and equipment life.
TDS and TSS Control Techniques
In controlling TSS, methods such as filtration, sedimentation, and the use of coagulants are often used. Filtration helps to remove large particles from water, while sedimentation allows suspended particles to settle out for easy removal. Coagulants, on the other hand, are chemicals that make suspended particles clump together, making them easier to separate from the water.
To reduce TDS, technologies such as reverse osmosis, demineralizers, and ion exchange resin are more relevant than ordinary particle filtration. RO uses a semipermeable membrane to reduce salts and dissolved ions, while demineralizers and ion exchange resin are used when process water needs lower conductivity or dissolved mineral content.
Reading Test Results to Select Treatment
| Water-quality finding | Operational meaning | Treatment direction to evaluate |
|---|---|---|
| High TDS, low TSS | The main load is dissolved salts or ions, not sludge. | RO, demineralizers, or ion exchange resin to reduce dissolved minerals. |
| High TSS, normal TDS | The main load is particles, sludge, biomass, or sediment. | Settling, sand filters, coagulants, flocculants, DAF, or ultrafiltration. |
| High TDS and high TSS | The water or wastewater needs pretreatment before membrane or polishing stages. | Clarification/filtration first, then RO, demineralization, or polishing according to the final quality target. |
| TSS rises suddenly | The site may have process changes, shock loading, poor backwash, or coagulation issues. | Review chemical dose, jar test results, sludge condition, and solids-separation performance. |
When does high TSS need a clarifier, DAF, or coagulation?
For high TSS, treatment selection depends on the solids form and separation method. If the particles settle readily, evaluate a Betaqua clarifier; the product page lists circular clarifiers at 50 m3/hr and rectangular clarifiers up to 80 m3/hr. If TSS is mixed with oil, grease, or fine particles that do not settle well, Dissolved Air Flotation (DAF) is more relevant because it uses microbubbles and a skimmer to float flocs to the surface.
For raw water or wastewater that remains turbid after settling, the chemical path should be checked through a jar test: Betagard coagulants neutralize particle charge, then flocculants help form flocs strong enough for clarifiers, DAF, filtration, or dewatering. Minimum data to send include TSS, turbidity, pH, alkalinity, flow rate, oil and grease where relevant, and the final effluent target.
Quick Questions on TDS and TSS
Is a TDS result enough to choose RO or a demineralizer? Not yet. TDS shows the total dissolved-solids load, but it does not identify the dominant ions or the required product-water quality. Selecting a brackish-water reverse osmosis system, process-water demineralizer, or ion exchange resin also requires raw-water analysis, the conductivity target, flow rate, operating hours, and the regeneration and waste-disposal requirements.
Is high TDS always dangerous? Not always. TDS shows the amount of dissolved solids, but the risk depends on the specific ions, the water application, and the quality limit to be met. Boiler water, RO feed, food-and-beverage process water, and cooling tower makeup usually need tighter TDS control than general utility water.
Can RO reduce high TSS? RO should not be the first treatment stage for water with high TSS. Particles should be reduced first through settling, coagulation-flocculation, filtration, DAF, or ultrafiltration so the membrane does not foul quickly.
What should an operator do when TSS rises suddenly? Hold dose changes until the sampling point, test method, flow, kg/day load, separation-unit condition, and upstream process changes are checked. Then use a jar test or controlled operating trial to test one correction at a time and record the effluent and sludge response.
What data should be prepared before a treatment review? Prepare TDS, TSS, pH, turbidity, COD/BOD for wastewater, flow rate, water source, and final quality target. These data help the technical team decide whether the process needs filtration, coagulation-flocculation chemistry, membranes, ion exchange, or a combination of stages. For system review, contact the Beta Pramesti Asia team.
Can turbidity replace TSS? Turbidity is useful as a quick operating alarm, but it is not automatically equal to TSS mg/L. The NTU-to-TSS relationship should be calibrated for that water with laboratory samples, especially when colour, oil, floc, or particle size changes.
Importance of TDS and TSS Monitoring
Regular monitoring of TDS and TSS is not only important to ensure healthier and safer water but also essential for the maintenance of a healthy ecosystem. This process helps identify and prevent pollution and contamination that may occur. Through effective monitoring, authorities can take immediate action to address water quality issues before they develop into bigger problems, ensuring the sustainability of water sources for humans and aquatic life.
Proactive monitoring and management of TDS and TSS allow operators to adjust treatment before water-quality changes become larger operating problems.
Conclusion: TDS and TSS Shape the Treatment Path
Understanding and managing Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) are fundamental aspects of effective water resources management. TDS helps determine the need to reduce dissolved minerals, while TSS helps determine the need to remove solids, sludge, or biomass before the water moves to the next process stage.
Routine monitoring of TDS and TSS allows operators to identify water-quality changes before they escalate into larger process or compliance issues. With consistent data, treatment can be adjusted through chemical-dose changes, filtration improvements, additional pretreatment, or more suitable membrane and ion exchange technology.
Preserved water quality not only helps meet basic human needs, but also supports industry, agriculture, and aquatic ecosystems. Investment in monitoring, jar testing, filtration systems, chemical treatment, and the right purification units is an investment in operating stability and long-term environmental compliance.
Decision Sequence for TDS and TSS Results
Do not select a unit from one TDS or TSS result. First confirm the method and sampling point, calculate daily load from a matching flow period, and then determine whether suspended solids, dissolved ions, or both constrain the process. This prevents an RO system from being used as a sludge filter or a clarifier from being specified for a dissolved-ion problem.
| Step | Minimum evidence | Decision supported |
|---|---|---|
| 1. Confirm the data | Labelled gravimetric TDS or conductivity, gravimetric TSS, pH, turbidity, flow and sampling time | Separate laboratory results from field-meter trends. |
| 2. Calculate the load | TSS (mg/L) × flow (m³/day) ÷ 1,000 | Establish kg solids/day for clarifier, DAF, filtration and sludge-capacity checks. |
| 3. Test solids separation | Jar test, floc character, oil/grease, and settling or flotation result | Screen coagulants, flocculants, a clarifier, or DAF. |
| 4. Characterise dissolved ions | Major ions, alkalinity, hardness, silica and product-water conductivity target | Assess brackish-water RO, a demineralizer, or ion exchange. |
| 5. Verify in operation | Before-and-after trends, filter differential pressure, effluent quality and sludge volume | Set response limits instead of treating one good sample as proof of stable capacity. |
Worked Solids-Load Example at Peak Conditions
Use TSS and flow from the same time interval. The figures below are not project design data; they show why an average-only calculation can understate both separation duty and sludge-handling demand.
| Example condition | TSS | Flow | Incoming load | If 85% of TSS is captured |
|---|---|---|---|---|
| Average operation | 250 mg/L | 600 m³/day | 150 kg/day | 127.5 kg/day enters the sludge route |
| Peak condition | 450 mg/L | 900 m³/day | 405 kg/day | 344.25 kg/day enters the sludge route |
In the peak example, the remaining 15% equals 60.75 kg/day. Convert that mass back to an effluent concentration with the actual flow before comparing it with a process target or applicable limit. Record peak duration too: a short surge may call for equalisation, while an all-day high load can alter clarifier sizing and sludge-treatment capacity. The 85% capture figure is a calculation assumption, not a performance guarantee.