The Menace of High TDS in Chemical Intermediates- Halophiles at rescue

Salts are one of the most omnipotent components present on Earth. Their presence and absence are significant in almost every chemical, physical, or biological process. Their concentration either depletes or enhances biological growth, preservation, and destruction. However, in effluent treatment plants, salts always have a destructive effect. High TDS in chemical intermediates is never welcomed by any ETP operator as it comes with operational ineffectiveness, damage to infrastructure, extreme difficulty in handling the effluent, non-compliance and high OPEX/CAPEX. Elevated TDS not only jeopardizes downstream operations, leading to scaling, corrosion, and product contamination, but also complicates effluent management, often forcing plants to deploy energy-intensive physicochemical treatments such as Multi-Effect Evaporators (MEE) and Reverse Osmosis (RO).

Although MEE/RO is effective, but is cost-intensive! so, what might be the alternative?  Well, here is the answer, HALOPHILES! Also known as halophilic bacteria, these salt-loving microbes offer a promising solution. This blog will help readers explore how halophiles in the form of microbial culture can help industries achieve operational excellence and reduce the effects and cost.

For more information or to discuss how our solutions can assist your operations, please contact us

The Impacts of High TDS :

High TDS streams in chemical intermediates plants often arise from:

  • Salt‐based reactants and catalysts: e.g., chlorides, sulfates, nitrates
  • Neutralization and pH control: addition of acid/base produces salts
  • Process by-products: dissolved organics, chelating agents, metal complexes
Operational Challenges
Effects of high TDS in chemical intermediates include:
  1. Scaling & Fouling
    • Precipitation of sparingly soluble salts (e.g., CaSO₄, BaSO₄) on heat‐exchange surfaces leads to reduced heat transfer and frequent downtime.
  2. Corrosion
    • Chloride‐rich brines attack stainless steels and other alloys, raising maintenance costs.
  3. Product Quality Risks
    • Carryover of salts compromises the purity of intermediates, requiring additional downstream purification.
Hampers Biological treatment: 
  • Due to high TDS, most of the biological wastewater treatment processes fail to generate effective biomass, hence hampering the efficiency.
Regulatory and Discharge Constraints
  • Effluent quality limits: Most jurisdictions cap TDS in discharge at 2,000–5,000 mg/L.
  • Brine disposal: Concentrated RO or evaporator brines often exceed tolerable disposal limits, leading to high disposal fees or zero-liquid discharge (ZLD) mandates.
  • Membrane/Equipment Damages:  Due to hampered biological wastewater treatment efficiency, most of the COD and dead biomass is carried into RO membranes results into their scaling or fouling in MEE.
Physicochemical Solutions: MEE & RO
Reverse Osmosis (RO)

Principle: Semi-permeable membranes allow water to pass under pressure while retaining salts.

  • Recovery ratio (R):
  • Typical performance: Recovery up to 75–85% for moderate TDS (<10,000 mg/L).
Pros:
  • Modular and relatively compact
  • High salt rejection (>99%)
Cons:
  • Membrane fouling/scaling requiring frequent cleaning
  • High‐pressure energy costs (2–6 kWh/m³)
  • Brine at 15–30% of feed volume
Multi‐Effect Evaporator (MEE)

Principle: A Series of evaporators reuses steam from one stage as the heating medium for the next, concentrating brine.

  • Steam economy: up to 8–10 kg steam/kg water evaporated.
Pros:
  • Handles very high TDS (>100,000 mg/L) and organics
  • Robust to feed variability
Cons:
  • Large footprint and capex
  • High thermal energy demand (often >500 kWh thermal/m³)
  • Generates a highly concentrated sludge

Halophilic Biocultures: A Biological Alternative

What Are Halophiles?
  • Definition: Microorganisms—including bacteria, archaea, and some fungi—that not only tolerate but require high salt concentrations (≥3% w/v NaCl) for optimal growth.
  • Types:
    • Moderate halophiles: 3–15% w/v NaCl
    • Extreme halophiles: 15–30% w/v NaCl
Mechanisms of Pollutant Removal
  1. Organic Degradation
    • Many halophiles express salt-stable enzymes (e.g., dehydrogenases, esterases) that mineralize refractory organics, aiding in biological TDS reduction.
  2. Biosorption of Inorganics
    • Cell walls and extracellular polymeric substances (EPS) bind heavy metals and ammonium ions, reducing dissolved load.
  3. Biomineralization
    • Certain strains precipitate metal sulfides or carbonates, facilitating solids separation.
Case Study: Halomonas spp. in High-Salinity Effluent:
ParameterUntreated EffluentAfter Halophilic TreatmentRemoval Efficiency
TDS (mg/L)45,00028,00038%
COD (mg/L)5,2001,10079%
NH₄⁺-N (mg/L)3104585%

In a pilot study, a consortium dominated by Halomonas elongata achieved near‐complete organic removal and 30–40% TDS reduction within 48 hours, showcasing the potential of TDS reduction using microorganisms.

Integration Strategies:
4.1 Hybrid Biological‐Physicochemical Systems
  1. Pre‐treatment with Halophiles + RO
    • Step 1: Use halophilic bioreactor to ingest organics and bind metals, lowering fouling precursors.
    • Step 2: Send biologically pre-treated stream to RO, extending membrane life and improving recovery.
  2. Post‐MEE Biological Polishing
    • Concentrate via MEE to moderate brine TDS (e.g., 80,000 mg/L → 120,000 mg/L).
    • Dilute and treat with halophiles to remove residual COD and ammonia, enabling partial recycling.
4.2 Reactor Configurations
  • Sequencing Batch Reactors (SBR): Ideal for flexible loading and high-salt adaptation cycles.
  • Membrane Bioreactors (MBR): Combine biomass retention with ultrafiltration, ensuring high mixed liquor suspended solids (MLSS).
  • Fixed-Film Reactors (e.g., Biofilm Carriers): EPS‐rich biofilms on carriers that thrive in saline feed.
Design & Operational Best Practices:
AspectRecommendation
Salinity GradientsGradual acclimation: start at 3% NaCl, ramp to process levels over 2–3 weeks.
pH ControlMaintain 7.5–8.5; extremes impair enzymatic activity.
Nutrient SupplementationC:N:P ratio of ~100:5:1 for robust growth.
Temperature30–37 °C to optimize halophilic metabolism.
Hydraulic Retention Time24–72 hours, depending on target removal efficiencies.
Mixing & OxygenationEnsure DO ≥2 mg/L for aerobic halophiles; N₂ sparging for anaerobic strains.
Economic & Environmental Benefits:
MetricConventional MEE/RO OnlyHybrid with Halophiles
Energy Consumption (kWh/m³)6–10 (electrical) + 500 (thermal)3–5 (electrical) + 300 (thermal)
Membrane Cleaning FrequencyEvery 2–4 weeksEvery 8–12 weeks
Brine Volume for Disposal (%)20–3010–15
Chemical Usage (antiscalants)HighModerate
Carbon Footprint (kg CO₂e/m³)15–208–12

By biologically reducing foulants and salinity, plants can halve brine volumes, extend membrane life, and cut overall energy and chemical costs by up to 30%. Moreover, the biodegraded organics lessen the environmental hazards of any unavoidable discharges, promoting eco-friendly chemical processing.

Conclusion:

High TDS in chemical intermediates has traditionally been corralled by MEE and RO—solutions that are effective but capital- and energy-intensive, and that generate challenging brines. Halophilic biocultures, however, offer a compelling biological route to alleviate TDS and organic loads, enhancing and de-risking conventional treatment trains. By integrating salt-adapted microbes—either as a pretreatment before RO or as a polishing step after evaporation—plants can achieve lower energy footprints, reduced chemical consumption, and more manageable brine streams.

As the industry seeks sustainability and cost-efficiency, harnessing the power of halophiles represents a strategic pivot: one that turns the very menace of high salinity into an opportunity for greener, sharper operations.

Are high TDS levels threatening your effluent compliance? Discover how a customized biological approach can turn the tide. Contact us to discuss a no-obligation site assessment and see how TeamOne’s expertise can optimize your industrial wastewater treatment.

📧 Email: sales@teamonebiotech.com

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why fresh bioculture takes time to show results in ETPs
The ‘Lag Phase’ Dilemma: Why Fresh Bioculture Doesn’t Work Instantly

In the world of biological treatment of wastewater, a common misconception persists: adding fresh bioculture for wastewater treatment guarantees instant results. Many operators expect immediate improvements in COD/BOD reduction or ammonia removal after dosing microbial culture into an underperforming ETP. But when visible results aren’t observed within a day or two, the bioculture for wastewater is often blamed for being ineffective.

Let’s decode this expectation mismatch, delve into a critical microbial phenomenon – the Lag Phase, and understand why even the best pure microbial culture doesn’t deliver overnight miracles. This is backed by operational realities and biological data that matter.👉 Contact us to learn how to optimize your microbial culture application.

Understanding the Microbial Growth Curve

Microorganisms, like all living systems, go through distinct phases of growth when introduced into a new environment:

  1. Lag Phase
  2. Log (Exponential) Phase
  3. Stationary Phase
  4. Decline (Death) Phase

The Lag Phase is the initial stage where no visible growth or activity is observed. However, this doesn’t mean microbes are inactive. During this phase:

  • Microbes adapt to the new environment.
  • Enzymatic systems are adjusted.
  • Gene expression is modified.
  • Cells are gearing up for division, not actively dividing yet.
 Why Does the Lag Phase Happen in ETPs?

When fresh bioculture is introduced into the aeration tank or bioreactor, several factors contribute to the length and intensity of the lag phase:

  1. Nutrient Profile Mismatch

Fresh microbes are often grown in optimized lab or fermenter media. When transferred to wastewater:

  • Nutrients may be imbalanced (e.g., low nitrogen or phosphorus).
  • Some carbon sources may be toxic or inhibitory (e.g., phenols, surfactants).
  • BOD:N:P ratio may be non-ideal (target is typically 100:5:1).

Example: If influent COD is 1000 mg/L and TKN is 5 mg/L → BOD: N ratio = 200:1 (far from ideal). This stresses fresh microbes, prolonging the lag phase.

This is why bioculture for removing ammoniacal nitrogen from effluent must be paired with proper nutrient profiling.

  1. Temperature and pH Shocks

Most bioculture strains are cultivated at optimal temperatures (25–35°C) and pH (6.8–7.5). When added to a field ETP:

  • Temperature fluctuations (e.g., influent temp of 18°C in winter) delay enzyme activation.
  • pH shocks (acidic wastewater from dye/textile units) inhibit microbial membrane transport.

Field data:

Fresh bioculture added at 5% v/v. Influent pH = 5.8 → no visible BOD reduction for 3 days. After pH correction to 6.8, activity began within 24 hours.

  1. Toxicity from Heavy Metals or Residual Chlorine

Heavy metals like Cr, Zn, and Cu or residual disinfectants like chlorine can denature proteins and kill cells, especially during initial exposure.

  • Tolerance limit for Cr = <0.5 mg/L
  • Chlorine residuals should be <0.1 mg/L before bio-activation

Example:
In one textile ETP, chlorine carryover from pre-treatment caused 90% loss of viable CFUs in 24 hours. Dechlorination was introduced → lag reduced from 4 days to 1.5 days.

Using anaerobic bioculture suppliers and dechlorination agents can significantly aid this transition.

  1. Low Dissolved Oxygen (DO) Levels

Bioculture organisms (especially nitrifiers) are aerobic. During start-up:

  • Oxygen demand spikes.
  • DO may drop below critical level (<2 mg/L).
  • Lag extends as microbes cannot activate oxidative enzymes efficiently.

Tip:
Maintain DO at 3–4 mg/L during startup even if it means temporary over-aeration.

  1. Microbial Competition and Protozoan Predation

Fresh microbes must compete with native microbes, and also survive protozoan grazing (e.g., Vorticella, rotifers).

  • If sludge age (MLSS age) is >20 days, floc-forming bacteria dominate, and new entrants struggle to establish.
📊 How to Monitor the Lag Phase in Real Time

Instead of waiting blindly, operators can use data-driven indicators:

ParameterExpected Behavior During LagComment
MLSSLittle to no changeNew cells not dividing yet
MLVSS/MLSS ratioLow (<0.65)High inert fraction initially
SOUR (mg O₂/g VSS/hr)Flat or very lowMicrobes not metabolizing
COD removal<10–20%Bioculture not active yet
Microscopic ObservationSmall, dispersed cells, few flocsNo protozoa or metazoans yet

Monitoring distribution of microbes in nature under a microscope can help detect early signs of colonization.

⏳ How Long is the Lag Phase?

The lag phase can last anywhere between:

  • 6–24 hours in ideal cases
  • 3–5 days in stressed systems
  • Up to 7+ days in shock-loaded or toxic wastewater
✅ Strategies to Shorten the Lag Phase
  1. Condition the System First
    • Neutralize pH
    • Eliminate residual chlorine
    • Adjust BOD:N:P ratio
  2. Pre-Activate Bioculture
    • Incubate with actual wastewater and aerate for 12–24 hours before dosing
  3. Gradual Acclimatization
    • Introduce microbes in stages
    • Avoid full load startup
  4. Supplement DO and Nutrients
    • Temporary aeration boost
    • Add Urea/DAP if needed
  5. Use Carriers or Media (optional)
    • MBBR or Biofilm carriers provide protection and surface for colonization
 Conclusion: Patience Pays

The lag phase isn’t a failure – it’s a biological necessity. It reflects the intelligent adaptability of microbes to their environment. With the right microbial culture methods, proper planning, real-time monitoring, system conditioning, and application this phase can be shortened, and biological performance optimized.

Next time you add a fresh bioculture, don’t just watch the COD meter. Watch the system parameters, the microbes under the microscope, and give them the right conditions and time.

Because in microbiology – nothing works instantly, but everything works eventually.

👉 Talk to our experts now to enhance your bioculture performance

To know more:

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📧 Email: sales@teamonebiotech.com   📲: 7769862121

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