The wastewater generated from the plant is collectivelypassed through the Bar screen chamber to remove the floating matter present inthe wastewater, oil and grease are removed in oil and grease chamber.
Thequality and quantity of the wastewater is maintained in the equilization tank wherecoarse diffusers of size 90mm dia and 800mm long are provided for the supply ofoxygen. The wastewater is then allowed to the aeration tank where the tank isprovided with fine diffusers of size 90mm dia and 1000mm long. The tank isseeded with DAP and oxidation of organic matter is done with the help ofmicro-organisms and here BOD and COD reduction takes place to a significantlevel. The treated wastewater is sent to secondary clarifier, here a smallamount of BOD and COD can be seen.
Portion of secondary clarifier sludge isrecirculated to aeration tank because it consists of already activatedmicrooragnisms. Then the wastewater treated by secondary treatment is allowedto a series Pressure Sand Filter (PSF) Activated Carbon Filter (ACF) and Ultrafiltration(UF) to remove the suspended solids and odour from treated wastewater. Finallythe treated wastewater enters the Reverse Osmosis (RO) unit where TotalDissolved Solids (TDS) are removed from the permit meanwhile TDS concentrationincreases in the reject. 1.4Sewage Treatment Plant (STP)TheSTPhas capacity of 10KLDand the units are shown in fig 1.3. The Domestic wastewatergenerated from canteen, flushing, and floor cleaning is collectively passedthrough the screen chamber to remove the egg shells and other things present inthe wastewater, oil generated from canteen is removed in oil and grease tank.
Thequality and quantity of the wastewater is maintained in the equilization tankthen it’s allowed to pre-aeration tank where the wastewater comes in contactwith atmospheric air, by this way aeration process starts from pre-aerationtank naturally without providing any diffusers. The aeration given to wastewaterthrough natural aeration process is not sufficient so the pre-aerated wastewateris then allowed to aeration tank where fine diffusers are provided to givesufficient amount of air. Here the aeration tank is provided with Moving BedBiofilm Reactor (MBBR) concept.
Where polyethylene innert media of 1.5 m3volume and 0.5 m height provides site for microbial growth and these microbesdegrade the waste by taking up as their food, once the microorganisms entersthe endogenious phase the film detaches from the media and settle to the bottomof settling tank when the wastewater is allowed to settling tank. Then the overflowed water from sellting tank is sent to clarifier for clarification purposelater it is sent to PSF and ACF to remove the TSS and odour, finally treatedwasrewater goes to ultravoilet unit for disinfection then the treated water isstored in a tank of capacity 7.2m3.
Sludge generated from treatmentprocess is sent to filter press for dewatering, formed filter cakes are used asmanure for gardening. Barscreen Oil Skimmer Equalization Tank Flash mixer (Alum dosing) Flocculator Primary clarifier Sludge holding tank Aeration Tank Secondaryclarifier Filter press PSF& ACF Ultrafiltration Microfiltration Reverse Osmosis Garden Fig 1.2 Treatment processes of ETP in TBK Bar screen Oil Skimmer Equalization tank Aeration TankSludge Holding Tank MBBR Aeration Tank Filter press Secondary Settling Tank Disposal Clarified Water Tank Pressure Sand Filter ActivatedSand Filter Ultra Voilet unit Filtered Water Tank To Irrigation Fig 1.3 SewageTreatment Plant in TBK 1.
5Environmental Impacts of Textile Wastewater The rapid but unplanned growth ofindustrial clusters, with several factories discharging large amounts ofuntreated or poorly treated wastewater leds to serious localized waterpollution (Assefa and Sahu, 2016). Theuntreated textile wastewater can cause rapid depletion of dissolved oxygen ifit is directly discharged into the surface water sources due to its high BODvalue. The effluents with high levels of BOD and COD values are highly toxic tobiological life. The high alkalinity and traces of chromium which is employedin dyes adversely affect the aquatic life and also interfere with thebiological treatment processes (Palamthodi et al., 2011). Wastewater contaminated by dyes represents arelevant issue associated with several industries. Dyes, even at very lowconcentrations, reduce wastewater transparency and oxygen solubility and areoften toxic and recalcitrant.
Moreover, these dyes and chemicals are toxic,carcinogenic or mutagenic for various organisms (Karekar et al., 2014). Thecolloidal matter present in oily scum increases the turbidity and gives thewater a bad appearance and foul smell. It prevents the penetration of sunlightnecessary for the process of photosynthesis when it is discharged into waterbodies and also hinders with self purification process of water.
In addition when this effluent isallowed to flow in the fields it clogs the pores of the soil resulting in lossof soil productivity. The texture of soil gets hardened and penetration ofroots is prevented. The wastewater that flows in the drains corrodes andincrustates the sewerage pipes.
If allowed to flow in drains it effects thequality of drinking water in hand pumps making it unfit for human consumption.It also leads to leakage in drains increasing their maintenance cost. Suchpolluted wastewater can be a breeding ground for many kind of microorganismssuch as bacteria and viruses.
Textile effluent is a cause of significant amountof environmental degradation and human illnesses. About 40 percent of globallyused colorants contain organically bound chlorine which is a known carcinogen.All the organic materials present in the wastewater from a textile industry areof great concern in water treatment because they react with many disinfectantsespecially chlorine.
1.6 PermissibleLimit for the Disposal of ETP and STP Treated Effluent The wastewater treated from both ETP and STP should meetthe standard specified by the Karnataka State Pollution Control Board and thesame is given in Table 1.1 and 1.2 Table 1.4 General DischargeStandards for Effluent Treatment Plant Parameters Standards for Inland Water Surface (mg/L) Standards for Land Disposal (mg/L) Colour and Odour See Note. See Note.
Suspended Solids (SS) 100 200 pH 5.5-9.0 5.5-9.0 Oil and Grease 10 10 Biological oxygen demand (BOD) 30 100 Chemical oxygen demand (COD) 250 250 Total Dissolved Solids (TDS) 2100 2100 Sulphide 02 – Residual Chlorine 1.0 – Ammonical nitrogen 50 – Nitrate Nitrogen 10 – Phosphate 5.0 – Source: Environmental (Protection)rules, 1986 Note: All effort should be made to remove colour andunpleasant odour as far as practicable. 1.
5 Effluent discharge standards for Sewage Treatment Plant Parameters Standards (mg/L) pH 6.5-9.0 Biological oxygen demand (BOD) 10 Total Suspended Solids (TSS) 20 Total residual chlorine 01 Oil and Grease 10 Chemical Oxygen Demand (COD) 50 Ammonia nitrogen 5 Total nitrogen 10 Fecal Coliform (MPN/100 ml) <100 Source: Ministry of Environment,2015 1.7 Scope of the Study Inthe present study Performance evaluation of both Effluent treatment plant and Sewagetreatment plants are done. Based on the performance evaluation laboratory scalestudies are carried out to bring down the pollutant level to disposalsatndards. Coagulation and Flocculation process is adopted as pre-treatment followedby Sequence batch reactor. Coagulation and flocculation is simple and rapidtechnique and also most often used pre-treatment techniques for treating thetextile wastewater. Sequence batch reactor is the most effective biologicaltreatment method adopted for the removal of Nitrate and Phosphate after thecoagulation and flocculation process.
1.8 Objectives Main objectiveTo evaluate the performace efficiency andoptimize the treatment process of effluent treatment plant and sewage treatmentplant at TBK Specific objectivesØ Tostudy the manufacturing process and characterise the wastewater generated fromindividual streams of manufacturing processØ Toevaluate the performance of individual treatment units of both ETP and STPØ Toconduct laboratory scale studies to improve the efficiency of ETP and STP basedon performance evaluationØ Todesign the treatment scheme to bringdown the pollutant level to disposalstandardsØ Toconduct kinetic study and statistical analysis for the data generated duringthe study Referenes1 Desai P. A. and Kore V. S. (2011). “Performance Evaluation ofEffluent Treatment Plant for Textile Industry in Kolhapur of Maharashtra”,journal of Mechanical and Civil Engineering, vol 1, pp 550-565.
2 Sumit kumar Patel, Dr. Anita Rajor, Dr.Bharat P. Jain, Payal Patel (2013) “PerformanceEvalutation of Effluent Treatment Plant of Textile Wet Processing Industry: casestudy of Narol Textile Cluster, Ahmedabad, Gujarat”. IJESIT, Volume 2,pp290- 296.
3 Swati A. Karekar, Bhorkar M. P, Dr.Thergaonkar V. P. (2014). “Performance Evaluation of Effluent Treatment Plant for Textile Mill atRamtek, MS, India”, Volume-11, pp 55-58. 4 Onur T, and Celaletti O, (2010).
“Wastewaterof Textile Industry and Its Treatment Processes”, BALWOIS 2010- Ohrid,Republic of Macedonia. 5 Tadele Assefa and OmprakashSahu (2016). ” Performance Analysis of TextileIndustry Wastewater Treatment Plant with Physicochemical Characterizations”, Journalof Environmental Treatment Techniques, vol 2, pp22-30. 6 Palamthodi Shanooba, Dhiraj Patil and YatinPatil, (2011) “Microbial degradation oftextile industrial effluents”, African Journ vol 10(59).