Optimized Industrial Effluent Treatment System (IETS) Performance & Troubleshooting

What is Industrial Effluent Treatment System and how to trobleshoot the issues during the operations

1. Optimized Industrial Effluent Treatment System (IETS) Performance & Troubleshooting Donald Ong Environmental Competency Consultancy Sdn. Bhd.

2. Speaker Profile Name: Donald Ong Year of Experience: 11 years Qualification: Bachelor Degree in BBA (Hons) Human Resource Development. Additional Qualification: CePIETSO-PCP & BP, CePSWAM and Certified HRDCorp Trainer Working Experience: R&D Executive, Environmental Engineer, Environmental Consultant and Technical & Training Director

3. What is IETS? short for industrial effluent treatment system means any facility including the effluent collection system, designed and constructed for the purpose of reducing the potential of the industrial effluent or mixed effluent to cause pollution.

4. Effects of water pollution

5. What are the common pollutants?

6. Importance of Waste Water System major aim of wastewater treatment suspended solids as possible before the effluent is discharged back to the environment. to avoid any harmful substance from being released to the surrounding

7. Activated Sludge Treatment System (ASTS) Processes

8. What is activated sludge? Wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa.

9. Activated Sludge Treatment Process

10. Activated Sludge Treatment System (ASTS) to remove the dissolved organic matter represented by carbonaceous BOD. This is achieved by the help of the microorganisms which are fed with the organic matter in the aeration tank. are also be used to remove the ammonia.

11. Types of Activated Sludge Treatment System (ASTS) Conventional activated sludge (CAS) Complete mix activated sludge (CMAS) Extended aeration activated sludge (EAAS) Sequencing batch reactors (SBR) Membrane bioreactor (MBR) Oxidation ditch activated sludge (ODAS)

12. PERFORMANCE MONITORING OF THE ACTIVATED SLUDGE SYSTEMS

13. Performance monitoring of the microbiological processes Uses microbes to biodegrade and remove the organic matter (i.e. the pollutant) contained in the industrial effluents Parameters to monitor Substrate pH Dissolved Oxygen Temperature Nutrients Mixed liquor suspended solids and mixed liquor volatile suspended solids Food to microorganism ratio Sludge age or sludge residence time Sludge volume index Oxygen uptake rate Oxidation reduction potential Microscopic examination Biochemical oxygen demand Chemical oxygen demand

14. Substrate food for the microorganisms for growth Organic matter is converted by the bacteria to energy, carbon dioxide, water and new cells(biomass) exhibit growth characteristics that undergo four distinct phases food is needed microbial community in the aeration tank to ensure healthy population which has good flocculating and settling properties ratio of the amount of food available to the amount of bacteria (F/M ratio)

15. pH influence on the ability of the microorganisms to work efficiently to eat the organic matter and convert it to energy. should be maintained in the range 6.5 to 8.5 Low pH(<6.5) promotes the growth of filamentous organisms which will cause bulking problems in the secondary clarifier

16. Dissolved oxygen require sufficient amount of dissolved oxygen to carry out the microbial activities to obtain energy Inadequacy in oxygen will retard the growth of the microbes and even death when prolonged resulting in objectionable odor recommended DO level is 1 to 2 mg/L for non-nitrifying systems and 2 to 3mg/L for systems that are required to nitrify

17. If the DO is allowed to drop to <1.0 mg/L over an extended period promote the growth of filamentous organisms which will result in settleability problems in the secondary clarifier. If the DO is allowerd to rise above the recommended range energy is wasted, floc particles may be floated to the clarifier surface solids carry over in the effluent may happen solids discharge standard may be violated

18. Temperature influences biodegradation of organic matter by the microbes increase in temperature = greater microbial activity = increase in oxygen demand and biomass (sludge) generation optimal temperature range of 10ºC to 30 ºC. also effects oxygen solubility in water

19. Nutrients to allow the microorganisms to perform the microbial functions in an efficient manner empirical chemical formula for the cell (C5H7O2NP) Carbon main building block of the cell of the microorganism and this is available as the organic substance in an organic industrial effluent. Nitrogen ammonia nitrogen is readily used by bacteria for biodegradation of organic matter. Phosphorus is required by the microorganisms in their energy metabolism, cell membrane and DNA production.

20. Mixed liquor suspended solids and mixed liquor volatile suspended solids consists of the effluent, dissolved and suspended substances, microorganism population (primarily bacteria, protozoa, and metazoa ) and inert materials. number of microbes decides the effective biodegradation of the organic matter bacterial population depends on MLSS concentration and MLVSS MLSS both the organic and the inorganic suspended solids MLVSS represents only the organic portion. representation of the concentration of microbes in the reactor

21. MLSS can be measured by standard gravimetric method or by using electronic meters and probes. typical MLSS concentration is 1500 to 3000 mg/L for an extended aeration, 3500 to 6000 mg/L.

22. Food to microorganism ratio represents the amount of food available to the microorganism F/M ratio increase, the rate of BOD removal, growth rate, and oxygen uptake rate (respiration rate) also increases. best F/M ratio depends on the type of ASTS and the characteristics of the industrial effluent being treated

23. Sludge age or sludge residence time residence time of the microorganisms or how long the microorganisms remain in the system.

24. Sludge volume index a measure of the settling characteristics of the sludge attempts to simulate, how the sludge will settle in the secondary clarifier.

25. Oxygen uptake rate indicates the activity level of the microbes and the status of the microbial population in the mixed liquor which influences the sludge quality and settling characteristics in the secondary clarifier. SOUR mg O 2 /hG.MLVSS SOUR Category Microorganism concentration Nature of microbial growth/microorganism involved Floc description,settling characteristic >20 High Low Logarithmic growth/Flagellates Dispersed floc,Settling Slow 12-20 Normal Normal Declining growth/ Ciliates Floc forming, Settling normal <12 Low High Endogenous respiration/Roriers and high life Pin floc, settling fast

26. Oxidation reduction potential indicates its oxidizing property or reducing property, a positive reading indicates that the effluent possesses an oxidizing property while a negative reading indicates that the effluent has a reducing property. Biochemical reaction ORP value, mV cBOD degradation with free molecular oxygen +50 to +250 Nitrification +100 to +350 Denitrification +50 to -50

27. Microscopic examination yield valuable information on the types of microbes present and their relative abundance. gives a practical evidence of the efficiency of the activated sludge treatment system (ASTS) presence of abundant population of ciliated protozoa indicates that the ATS is being optimally operated and is functioning well and producing good quality effluent.

28. Predominant group Efficiency Possible cause Small flagellates Very low Bad Oxygenation of the sludge, loading that is too high,presence of fermenting substances Small swimming ciliates(< 50 µm ) Low Contact time too short; low oxygenation of the sludge Large swimming ciliates(> 50 µm ) Low Loading that is too high Crawling ciliates Good Crawling + attaches ciliates Good Attached ciliates Decreasing Unsteady state (discontinuous feeding sludge wastage) Small amoebae (with and without flagellum) Very low Loading that is too high, not easily biodegradable Amoebae with shell Good Low loading diluted mixed liquor, good nitrification

29. Biochemical oxygen demand and chemical oxygen demand measure the gross organic matter content in an effluent sample. is a natural reaction which happens in a BOD bottle, or in an aeration tank, or in a stream. indicates its potential to cause oxygen depletion in the receiving stream if the organic matter is not adequately removed in the treatment system prior to the discharge of the effluent. to determine the efficiency of the treatment system in removing the organic matter.

30. Biochemical oxygen demand and chemical oxygen demand organics removal efficiency based on BOD can simply be calculated by using the formula below.

31. COMMON ASTS OPERATIONAL PROBLEMS

32. Common problems in ASTS operation Problems are usually encountered in the clarification stage bulking sludge rising sludge ashing foam. All of above phenomena lead to "settling problems" in the secondary clarifier which results in the occurrence of turbid and noncompliant effluent

33. Bulking sludge sludge exhibits poor settling characteristics and poor compactability. 2 types of sludge bulking problems - caused by the growth of filamentous organism - caused by bound water Rising sludge sludge is observed to rise or float to the clarifier surface. Ashing very fine sludge particles which may exist in secondary clarifiers or in several cases even in aeration tanks Foam caused by Nicardia appears as viscous brown foam that covers the aeration tanks and secondary clarifiers. cause safety issue and nuisance to neighbors

34. Causes of sludge nonsettling problems

35. Causes of sludge bulking The effluent aspect effluent characteristics that will promote the growth of filamentous organisms include: Air supply capacity Clarifier design Return sludge pumping capacity Short circuiting Poor mixing

36. Operational causes of filamentous bulking include: Low dissolved oxygen in the aeration tank, Insufficient nutrients Widely varying organic waste loading Low F/M ratio High F/M may result in the presence of small disperse flocs Insufficient soluble BOD gradient

37. Most commonly observed filamentous bacteria implicated for causing sludge bulking in activated sludge systems are: Nocardia spp. Type 1701 Nocardia spp. Type 021N Type 0041 Thiothrixspp . Sphaerotilus natans Microthrix parvicella Type 0092 Haliscomenobacter hydrossis Type 0675

38. Causes of rising sludge can only occur in a case where the effluent contains ammonia. If the dissolved oxygen levels are sufficiently low in the settling tank and there is some organic matter available, denitrification will take place as a result of the actions of several groups of anoxic bacteria (denitrifiers). The nitrates will be converted to nitrogen gas which gets attached to the sludge mass causing it to become buoyant and rise to the surface. Rising sludge can easily be differentiated from a bulking sludge by noting the presence of small gas bubbles attached to the floating solids. Most industrial effluents do not contain nitrogen ,hence rising sludge is not a common problem in IETS operation.

39. Causes of ashing occurrence of fine sludge particles in secondary clarifiers in extended aeration activated sludge systems. EAAS systems are operated in endogenous phase of the growth curve where the microorganism are kept in under “starvation” conditions.

40. Causes of Nicordia foam viscous brown foam is associated with a slow growing filamentous organism usually Nocardia genus. Probable causes of the promoted growth of Nocardia are low F/M in the aeration tank high MLSS due to insufficient sludge wasting and sludge reaeration.

41. TROUBLESHOOTING ASTS OPERATIONAL PROBLEMS Bulking sludge, Rising sludge and Nicordia foaming.

42. Microscopic examination take a sample of the mixed liquor or the foam and examine it under the microscope. will help us identify the cause of the problem, whether the problem is caused by filamentous organism(s) or not, and what organisms are involved.

43. Types of filamentous organism involved with different causative conditions Causative Condition Causative Filament Types Low Dissolved Oxygen (for the applied organic loading) S. natans, type 1701 and H. hydrossis. Low Organic Loading Rate > (low F/M) M. Parvicella, Nocardia spp., and types 0041,0675,1851 and 0803. Septic Wastes / Sulfides (high organic acids) Thiothrix I and II, Beggiatoa spp., N. Limicola II*, and types 021N, 0092*, 0914*, 0581*, 0961* and 0411. Nutrient Deficiency- N and/or P (industrial wastes only) nitrogen- phosphorus- Thiothrix I and II and type 021N. N. Limicola III Low pH(<pH 6.0) Fungi High Grease/Oil Nocardia spp., M. parvicella and type 1863 (These filaments occur at lower F/M at septic conditions.)

44. Remedial actions Once the type of causative filamentous organisms has been identified through microscopic examination, the next step is to match it with the possible causative conditions. When we have found the possible match, start taking the remedial actions as discussed below.

45. Low dissolved oxygen concentration 2 dissolved oxygen (DO) levels that are relevant to the activated sludge treatment process: the bulk DO and the DO within the floc. if an ASTS is operated at a F/M ratio higher then 0.5, even higher bulk DO level needs to be maintained.

46. Low food to microorganism ratio lower the MLSS concentration which would result in increasing the F/M when “M” is lowered, and F remains constant, F/M will reduce. lowering of MLSS means that sludge wasting will need to increase. to increase sludge wasting - compartmentalization of aeration basins; - fed-batch operation; - intermittent feeding of wastes; - use of a selector tank.

47. Low pH Aeration pH can be adjusted using - caustic , - lime - magnesium hydroxide.

48. Septicity indicators of septicity are dark coloration of the effluent remedy is to treat by pre-aeration(to releases odors), by chemical oxidation (by using chlorine, hydrogen peroxide or potassium permanganate), by chemical precipitation (by using ferric chloride as coagulant), or use of sodium nitrate in the collection system as an “oxygen source”.

49. Other remedial actions

50. Use of chemical agents to reduce the impact of filamentous bulking and enhance activated sludge settling. most commonly used chemicals are synthetic, high molecular weight, cationic polymers which are used alone or in combination with an anionic polymer. usually added to the MLSS as it leaves the aeration basin or to the secondary clarifier center well . should be preceded by jar testing to determine the type of polymer which is effective and its required dosage

51. Other substances include inorganic coagulants such as lime or ferric chloride and clay and fiber.

52. Chemical oxidation to expose the activated sludge to sufficient chlorine to damage filaments extending from the floc surface while leaving organisms within the floc largely untouched. Chlorine dosage is adjusted such that its concentration is lethal at the floc surface but is sublethal within the floc.

53. Three common chlorine addition points are : into the RAS stream at a point of turbulence (elbows in pipes; into the volute or discharge of RAS pumps; and into and below liquid level in a riser tube of an airlift RAS pump); directly into the final clarifier center well or feed channel; and in an installed sidestream where the MLSS is pumped from and returned to the aeration basin. Chlorine addition to the RAS line(s) Chlorine addition to the aeration basin does not work and only causes floc dispersion and system damage.

54. Foaming Activated sludge foaming is caused mostly by two filaments : Nocaedia spp. and Microthrix parvicella causes : (1) high grease and oil (2) long sludge age (3) low oxygen conditions or septicity.

55. Effective removal techniques of oil and grease must be implemented to reduce the entry of grease into the aeration tank. RAS chlorination is not effective on Nocardia foam, but is applicable to M. parvicella . Antifoam agents are not effective on both types of foam. Reducing sludge age to less than 8 to 10 days Foams should be removed and not allowed to build up the surface of aeration basins and final clarifiers. This can be achieved by using enlarged surface scum traps and forceful water sprays to carry this material our of the aeration basin or the clarifier.

56. Prevention is better than cure Filamentous bulking can be prevented by paying attention to the following: Maintain the optimum F/M ratio Prevent low D.O. Stop grease from entering the aeration tank Apply anoxic zone or cycle in the treatment train

57. Q & A Session Thank You