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TEXTILE INDUSTRY CASE STUDY
How a 600 KLD Textile ETP Improved MLVSS from 17% to 69% & COD Removal to 75%
Industry: Textile Manufacturing (Washing, Bleaching, Mercerizing, Sizing, Desizing & Dyeing Processes)
Location: Perundurai SIPCOT Industrial Area, Erode District, Tamil Nadu, India
Plant Capacity: 600 KLD ETP with Zero Liquid Discharge (ZLD) RO Polishing
17% → 69%
MLVSS Growth within 15 Days
0.15 ppm DO
Septic State Completely Reversed
75% COD Removal
Eradicated Permeate Odour
A 600 KLD textile ETP in Tamil Nadu faced critically low DO of 0.15 ppm, negligible active biomass and poor COD reduction due to complex dyes and chemicals. Amalgam Biotech implemented BactaServe Textile, NutriServe Oxy Enhancer and Rapid Oxidizer, increasing MLVSS from 17% to 69% within 15 days and COD removal from 40% to 75%.
Background & Technical Challenge
Plant Overview
A textile manufacturing facility located in Perundurai SIPCOT Industrial Area, Erode District, Tamil Nadu, operates a 600 KLD ETP for treating wastewater generated from multiple wet-processing operations, including washing, bleaching, mercerising, sizing, desizing and dyeing. The wastewater contains a complex mixture of textile dyes and process chemicals that creates a significant biological treatment load.
The ETP incorporates primary clarification, biological aeration, secondary settling, tertiary chemical treatment, ultrafiltration and reverse osmosis (RO) to treat the effluent and support water recovery. However, the biological treatment stage was unable to maintain adequate active biomass and dissolved oxygen, affecting overall COD/BOD degradation and downstream water quality.
The facility's aeration tank had critically low DO of only 0.15 ppm, while the active MLVSS:MLSS ratio was just 17%. This poor biological condition limited COD reduction to approximately 40% and contributed to septic conditions, with the aeration tank developing a blackish appearance. The incomplete biological treatment also resulted in unpleasant odours reaching the downstream RO permeate.
The treatment challenge therefore required simultaneous improvement of dissolved oxygen, active biomass development, organic degradation and RO permeate odour control without relying solely on additional mechanical aeration capacity.
The Technical Challenge & Risk
Critically Low DO: Dissolved oxygen in the aeration tank fell to just 0.15 ppm, creating conditions unsuitable for maintaining healthy aerobic biological activity.
Negligible Active Biomass: The MLVSS:MLSS ratio was only 17%, indicating a very low proportion of active biological biomass available for COD and BOD degradation.
Complex Textile Wastewater: Dyes including Reactive, Vat, Disperse, Indigo and Acid dyes, together with sizing chemicals, starch, PVA, cellulose and lignin, created a difficult-to-degrade organic load.
Poor COD Reduction: Biological COD reduction was limited to approximately 40%, indicating insufficient biological activity for effective organic degradation.
Septic Aeration Conditions: Low DO caused the aeration tank to turn blackish, indicating septic conditions and poor biological health.
RO Permeate Odour: Inadequate biological treatment allowed odour-causing compounds to persist through downstream treatment, resulting in unpleasant odours in the RO permeate.
Treatment Process Flow Diagram
The 600 KLD textile ETP follows a multi-stage treatment process combining primary clarification, biological aeration, secondary settling, tertiary chemical treatment and membrane polishing. The biological stage is the key treatment zone where BactaServe Textile and NutriServe Oxy Enhancer were applied to rebuild active biomass and restore aerobic conditions.
Process Flow
Raw Effluent → Collection Tank → Mixing Channel → Primary Clarifier → Aeration Tank → Secondary Clarifier → Tertiary Chemical Treatment → Tertiary Clarifier → UF → RO → Treated Water
Process Overview
Primary Clarification: Removes settleable solids from the incoming textile effluent before biological treatment.
Aerobic Biological Treatment: The aeration tank receives BactaServe Textile and NutriServe Oxy Enhancer to support active biomass development and maintain sufficient DO for biological degradation.
Secondary Clarification: Separates biological solids from the treated wastewater following aeration.
Tertiary Treatment: Provides additional chemical treatment and clarification before membrane polishing.
UF & RO Treatment: Ultrafiltration followed by RO provides final membrane treatment for water recovery. NutriServe Rapid Oxidizer was applied to address foul odours associated with the RO permeate.
Bio-Augmentation Strategy & Dosing
Why BactaServe™ Textile & NutriServe™ Solutions Were Selected
To restore biological treatment performance in the 600 KLD textile ETP, Amalgam Biotech implemented an integrated treatment strategy using BactaServe Textile, NutriServe Oxy Enhancer and NutriServe Rapid Oxidizer. The solution was selected to address three connected problems: critically low DO, negligible active biomass and unpleasant odours in the RO permeate.
Unlike a single-product biological treatment approach, each product was applied to a specific treatment requirement. BactaServe Textile was used to develop active biomass and support COD/BOD degradation, NutriServe Oxy Enhancer was applied to increase DO and reverse septic conditions in the aeration tank, while NutriServe Rapid Oxidizer was used to neutralise foul odours in the RO permeate.
Key Benefits
Increased active MLVSS in the aeration tank
Improved biological COD reduction
Supported degradation of complex textile dyes and chemicals
Increased DO in oxygen-starved aeration conditions
Helped reverse septic conditions in the aeration tank
Improved biological treatment performance
Eliminated unpleasant odours from RO permeate
Supported stable operation of the existing ETP without major process changes
Integrated Biological & Treatment Strategy
The three products were applied at different stages to address the specific treatment limitations observed in the textile ETP. BactaServe Textile focused on biomass development and organic degradation, NutriServe Oxy Enhancer supported aerobic conditions, and NutriServe Rapid Oxidizer addressed residual odour compounds in the treated water.
1. Active Biomass Development
BactaServe Textile builds active biomass for COD/BOD degradation.
2. Dissolved Oxygen Enhancement
NutriServe Oxy Enhancer increases DO in the aeration tank.
3. COD Reduction
BactaServe Textile improved COD reduction from 40% to 75%.
4. RO Permeate Odour Control
NutriServe Rapid Oxidizer neutralises foul odours in RO permeate.
30-Day Dosing Protocol (600 KLD Program)
Treatment Period | BactaServe Textile | NutriServe Oxy Enhancer | NutriServe Rapid Oxidizer |
Days 1 to 10 | 8 kg/day | 4 kg/day | 3 kg/day |
Days 11 to 20 | 4 kg/day | 4 kg/day | 3 kg/day |
Days 21 to 30 | 3 kg/day | 4 kg/day | 3 kg/day |
30-Day Total | 150 kg | 120 kg | 90 kg |
*Dosing note: The specified daily quantities of NutriServe Oxy Enhancer and NutriServe Rapid Oxidizer were divided into three equal portions for dosing across three shifts.
Performance Results & Analytics
Key Metrics Achieved
69% Active MLVSS: MLVSS:MLSS ratio increased from 17% to 69% within 15 days, indicating rapid active biomass development.
75% COD Reduction: Biological COD reduction improved from 40% to 75% after BactaServe Textile application.
0.15 ppm DO Recovery: NutriServe Oxy Enhancer addressed critically low 0.15 ppm DO, helping reverse septic conditions in the aeration tank.
RO Permeate Odour Eliminated: NutriServe Rapid Oxidizer was applied to eliminate unpleasant odours from the RO permeate, improving treated water quality.
System Performance Comparison
System Metric | Pre-Treatment Baseline | Post-Treatment State |
Dissolved Oxygen (DO) | 0.15 ppm (Severe Septic) | Elevated / Healthy Aerobic |
Aeration Tank Color | Septic Blackish | Healthy Active Brown |
MLVSS : MLSS Ratio | 17% (Negligible Biomass) | 69% (Within 15 Days) |
Biological COD Reduction | 40% (Poor Removal) | 75% (Substantial Removal) |
RO Permeate Water Quality | Unpleasant Foul Odor | Clean, Clear & Odor-Free |
Before and after comparison showing the aeration tank changing from blackish septic conditions to a healthy brown appearance after NutriServe Oxy Enhancer treatment.
Client Feedback: MLVSS Growth, COD Reduction & Septic Condition Recovery
“Our 600 KLD textile ETP was facing critically low DO, negligible biomass and poor COD reduction due to the complex dyes and chemicals in our wastewater. After implementing BactaServe Textile with NutriServe Oxy Enhancer and Rapid Oxidizer, MLVSS increased from 17% to 69% within 15 days, COD reduction improved from 40% to 75%, and the foul odour in our RO permeate was eliminated.”
ETP Operations Manager
Textile Manufacturing Facility, Perundurai SIPCOT, Tamil Nadu
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Facing Low DO, Septic Aeration, or RO Permeate Odors in Your Textile Mill?
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Step 1: Share your process details and treatment objectives.
Step 2: Our engineers assess your system and operating conditions.
Step 3: Receive a tailored solution and implementation plan.
Frequently Asked Questions
Q1. How did the integrated Amalgam Biotech solution reverse septic conditions and achieve 75% COD removal in a 600 KLD textile ETP?
Amalgam Biotech used a 3-product bio-chemical strategy at a 600 KLD textile ETP in Perundurai SIPCOT, Tamil Nadu. NutriServe Oxy Enhancer reversed the septic 0.15 ppm DO condition, BactaServe Textile increased MLVSS from 17% to 69%, and NutriServe Rapid Oxidizer controlled persistent foul odours, supporting 75% COD removal.
Performance Highlights:
Target Waste Stream: High-load textile wet-processing effluent containing reactive, disperse, indigo, and acid dyes, along with sizing PVA, starch, and surfactants.
Biomass Recovery: Increased the active MLVSS:MLSS ratio from 17% to 69% within 15 days.
Aeration Tank Transformation: Changed the aeration tank from an oxygen-starved, septic blackish condition to a healthy aerobic brown appearance.
Q2. Why does critically low Dissolved Oxygen (0.15 ppm) turn textile aeration tanks black and septic?
When biological oxygen demand exceeds the available aeration capacity, Dissolved Oxygen (DO) can fall below 0.5 ppm. Under these oxygen-limited conditions, facultative bacteria can reduce sulphates from textile dye baths to hydrogen sulfide (H₂S), which reacts with dissolved metals to form black iron sulfide and produces septic odours.
Process Impact:
Biomass Suffocation: Aerobic nitrifiers and heterotrophic carbon-degrading bacteria lose activity, reducing active MLVSS to 17%.
Incomplete COD Removal: Biological COD removal can fall to around 40%, allowing refractory dye compounds to pass into tertiary treatment.
Q3. How does NutriServe Oxy Enhancer elevate Dissolved Oxygen without requiring extra mechanical aerators?
NutriServe Oxy Enhancer is a specialised chemical additive that improves oxygen transfer and provides sustained chemical oxygen directly in the liquid phase. It helps reduce oxygen stress, supports existing blowers, and rapidly restores aerobic conditions in oxygen-depleted aeration basins without requiring additional mechanical aerators.
Operational Benefits:
Fast Reversal: Helps quickly recover aeration tanks from septic black conditions without capital-intensive blower upgrades.
Shift-Wise Dosing: Divided into 3 equal daily shift doses, with a total dosage of 4 kg/day, to maintain oxygen availability.
Q4. What was the 30-day multi-product dosing protocol for the 600 KLD textile ETP?
The 30-day programme combined 150 kg of BactaServe Textile, 120 kg of NutriServe Oxy Enhancer, and 90 kg of NutriServe Rapid Oxidizer. BactaServe Textile was reduced from 8 kg/day to 3 kg/day, while Oxy Enhancer remained at 4 kg/day and Rapid Oxidizer at 3 kg/day across three 8-hour shifts.
Protocol Progression:
Days 1 to 10 (Shock Recovery): 8 kg/day BactaServe + 4 kg/day Oxy Enhancer + 3 kg/day Rapid Oxidizer to support rapid biomass recovery and DO improvement.
Days 11 to 20 (Stabilisation): 4 kg/day BactaServe + 4 kg/day Oxy Enhancer + 3 kg/day Rapid Oxidizer to stabilise the 69% MLVSS ratio.
Days 21 to 30 (Maintenance): 3 kg/day BactaServe + 4 kg/day Oxy Enhancer + 3 kg/day Rapid Oxidizer to maintain long-term biological stability.
Q5. How did NutriServe Rapid Oxidizer eliminate foul odours in the Zero Liquid Discharge (ZLD) RO permeate?
Incomplete biological oxidation can allow volatile organic sulphides and low-molecular-weight amines to pass through Ultrafiltration and Reverse Osmosis (RO) systems. NutriServe Rapid Oxidizer chemically neutralises these volatile odour compounds in the polished permeate without increasing Total Dissolved Solids (TDS).
Downstream Water Reuse:
Odour-Free Permeate: Converts foul-smelling RO permeate into clean, odour-free water suitable for direct reuse in textile washing and dyeing.
Membrane Compatibility: Does not leave residual foulants that could contribute to irreversible membrane biofouling or reduce RO membrane life.
Q6. What complex refractory chemicals in textile wastewater are broken down by BactaServe Textile?
BactaServe Textile produces specialised enzymes that help break down complex azo and aromatic bonds in Reactive, Vat, Disperse, Indigo, and Acid dyes. It also helps hydrolyse sizing materials such as Polyvinyl Alcohol (PVA), starch, cellulose, lignin, and residual wetting surfactants.
Enzymatic Action:
Azo-Reductases & Laccases: Break down refractory dye chromophores to support wastewater decolourisation.
Polysaccharide Hydrolases: Break down complex sizing materials and organic polymers, helping reduce foaming and solids carryover into secondary clarifiers.
Written by Ashutosh Vadanagekar
Technical Director, Amalgam Biotech
Ashutosh Vadanagekar has over 22 years of experience in water and wastewater treatment, with expertise in process design and bioculture technology. He develops and implements eco-friendly biological treatment solutions for ETPs and STPs across industries, addressing challenges such as high COD and BOD, ammonia, FOG, odour and biological process instability. He also contributes technical expertise and practical insights to Amalgam Biotech’s wastewater treatment case studies. Connect on LinkedIn