Industrial wastewater treatment

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San Pedro, J., D Perio, K., Gutierrez, L.A., Mina, J.A. & Cano, J.C.,

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1. INDUSTRIAL WASTEWATER TREATMENT MEID 513 BSME-5F SAN PEDRO, JESSA O. DE PERIO, KATE G. CANO, JOHN CHRISTIAN A. GUTIERREZ, LEIGH ANNE A. MINA, JULIE-ANN C.

2. INTRODUCTION ● Industries use water that obtained from the water treatment system for a variety of purposes, such as For manufacturing goods. For heating. For cooling. As carrier of raw material. As carrier of waste matter. As a solvent. ● The resulting water after several processes is then classified as wastewater .

3. INTRODUCTION ● The indiscriminate discharge of these wastewater streams into the environment can: Render soils "sick ". Pollute the receiving bodies of water. Cause air pollution by generating obnoxious gases ● Discharge untreated wastewater into the domestic sewer system makes the task of treating domestic sewage, a very difficult and costly exercise .

4. INTRODUCTION To prevent any health hazards caused by discharging wastewater into the environment and protect domestic sewage, the wastewater must be treated before discharge or an INDUSTRIAL WASTEWATER TREATMENT must be done.

5. WHAT IS INDUSTRIAL WASTEWATER TREATMENT? Industrial wastewater treatment covers the mechanisms and processes used to treat waters that have been contaminated in some way by anthropogenic industrial or commercial activities prior to its release into the environment or its re-use. SEWAGE TREATMENT PROCESS WASTEWATER TREATMENT PROCESS

6. WHAT IS THE OBJECTIVE OF INDUSTRIAL WASTEWATER TREATMENT? The principal objective of industrial wastewater treatment is generally to allow industrial effluents to be disposed of without danger to human health or without unacceptable damage to the natural environment . Another objective of industrial wastewater treatment to manage water discharged from homes, businesses, and industries to reduce the threat of water pollution .

7. IMPORTANT CONTAMINANTS OF CONCERN IN INDUSTRIAL WASTEWATER TREATMENT WASTEWATER CONTAMINANTS Suspended Solids Nutrients (P, N 2 , C) Priority Pollutants Refractory Organics Heavy Metals Dissolved Inorganics

8. SOURCES OF INDUSTRIAL WASTEWATER TREATMENT BREWERIES DAIRY INDUSTRY PULP AND PAPER INDUSTRY IRON AND STEEL INDUSTRY MINES AND QUARRIES PULP AND PAPER INDUSTRY

9. SOURCES OF INDUSTRIAL WASTEWATER TREATMENT COMPLEX ORGANIC CHEMICALS INDUSTRY NUCLEAR INDUSTRY TEXTILE INDUSTRY LANDFILL LEAKAGE PHARMACEUTICAL INDUSTRY GLASS INDUSTRY

10. THREE CLASSIFICATIONS OF INDUSTRIAL WASTE WATER

11. The first type is classified according to the chemical properties of the main pollutants contained in industrial wastewater. The inorganic pollutants are mainly inorganic wastewater, and the organic pollutants are mainly organic wastewater. For example, electroplating wastewater and wastewater from mineral processing are inorganic wastewater; wastewater from food or petroleum processing is organic wastewater. Petroleum Processing Wastewater Electroplating Wastewater Food Wastewater

12. The second is classified according to the products and processing objects of industrial enterprises, such as metallurgical wastewater, papermaking wastewater, coking coal gas wastewater, metal pickling wastewater, chemical fertilizer wastewater, textile printing and dyeing wastewater, dye wastewater, tannery wastewater, pesticide wastewater, power station wastewater, etc. Dye Wastewater Power Station Wastewater Metallurgical Wastewater

13. The third type is classified according to the main components of the pollutants contained in the wastewater , such as acidic wastewater, alkaline wastewater, cyanide-containing wastewater, chromium-containing wastewater, cadmium-containing wastewater, mercury-containing wastewater, phenol-containing wastewater, aldehyde-containing wastewater, and oily wastewater. , sulfur-containing wastewater, organic phosphorus wastewater and radioactive wastewater, etc. Oily Wastewater Radioactive Wastewater

14. CLASSIFICATION OF INDUSTRIAL WASTE WATER TREATMENT

15. Mechanical Processes 1. Screening - The first unit operation encountered in wastewater-treatment starts in screening. A screen is a device with openings, generally of uniform size that is used to retain the coarse solids found in wastewater. Step Screens  are a ”stepping” type of screening systems for separating suspended solids.

16. 2. Oil Separation It is a process in which floatables , namely non-emulsifies oil and organics separate from wastewater. API (American Petroleum Institute) Separators, - This separator can handle very large flow . It is designed based the specific gravity difference between the oil and the wastewater and between the suspended solids and wastewater. API Separator

17. CPI (Corrugated Plate Interceptors) Units Consist of stacks of plates or bundles of slanted tubes usually at 60 degrees , in a vessel or tank. The solids will slide down the plates and be collected at the bottom. They are usually more efficient than API Separators in removing oil and solids, as more surface area can be provided. CPI Units

18. 3. Flow Equalization It is used to overcome the operational problems caused by flow variations and is also used as an emergency tank to equalize wastewater effluent in case of any process failure in the treatment process. The design must provide for sufficient mixing to prevent solids deposition and concentration variations and also to provide aeration to prevent odor problems.

19. Physical Treatment Sedimentation It is the separation from water, by gravitational settling , of suspended particles that are heavier than water. Sedimentation basins are constructed in a variety of shapes and sizes, circular tanks or rectangular tanks , which is comprised of four zones according to function: a.) Inlet Zone is a region where the incoming suspension is distributed uniformly over the cross- section of the tank. b.) Settling Zone , the particles settle at the same rate as they would in a quiescent.

20. c.) Outlet zone , the clarified liquid is collected uniformly over the cross-section of the basin. d.) Sludge Zone is where all the solids collect at the bottom of the tank. Rectangular Basin Circular Basin

21. 2. Floatation It is a unit operation used to separate solid or liquid particles from a liquid phase. Principal advantage of floatation over sedimentation is that very small or light particles that settle slowly can be removed more completely and in a shorter time.

22. TYPES OF FLOATATION SYSTEMS Air Flotation – air bubbles are formed by introducing the gas phase directly into the liquid phase through a revolving impeller through diffusers. Vacuum Flotation – consists saturating the wastewater with air either directly in an aeration tank or by permitting air to enter on the suction side of a sewage pump. Air Flotation Vacuum Flotation

23. Chemical Treatment Neutralization Industrial wastes often contain acidic o alkaline components which require neutralization before discharge or treatment. Lime is the most widely used alkaline material for neutralization acid wastes because of its low cost .

24. 2. Oxidation / Reduction Oxidants are used in wastewater treatment as a first step in the removal of heavy metal to oxidize organics or as a last step in a treatment process, to oxidize odoriferous compounds such as hydrogen sulfide or to oxidize inorganics such as cyanide and for disinfection. Oxidation / Reduction

25. 3. Chemical Precipitation - Chemical precipitation in wastewater treatment involves the addition of chemicals to alter the physical state of dissolved and suspended solids and facilitate their removal by sedimentation . Chemical Precipitation

26. Coagulation Takes place in rapid mix, or flash mix basins which are very rapid. The primary function of rapid mix basin is to disperse the coagulant so that it contacts all of the wastewater. Flocculation - form aggregates or flocs from the finely divided matter . The flocculation of wastewater by mechanical or air agitation.

27. Physico -chemical treatment focuses primarily on the separation of colloidal particles . This is achieved through the addition of chemicals (called coagulants and flocculants), which change the physical state of the colloids allowing them to remain in an indefinitely stable form and therefore form into particles or flocs with settling properties. Physico -Chemical Treatment

28. PHYSICO-CHEMICAL TREATMENT Coagulation (rapid mixing) - Destabilizes or neutralizes the negative charges contained in the wastewater by adding a coagulant during rapid mixing Flocculation (slow mixing) - Flocculants are applied to allow flocs to come together and adhere Sedimentation - Floc removal by solid - liquid separation. STAGES

29. Biological treatment cleans water by using bacteria, nematodes, or other small organisms to break down organic wastes. This treatment is often a secondary treatment process, used to remove any material remaining after primary treatment. Biological Treatment

30. BIOLOGICAL TREATMENT CATEGORIES Aerobic Treatment -   microorganisms require oxygen   to break down organic matter to carbon dioxide and microbial biomass. Anoxic Treatment -   microorganisms use other molecules than oxygen  for growth, such as for the removal of sulfate, nitrate, nitrite, selenate , and selenite. Anaerobic Treatment -   microorganisms do not require oxygen   to break down organic matter, often forming methane, carbon dioxide, and excess biomass.

31. Disinfection – Disinfection refers to the selective destruction of disease-causing organisms. It is most commonly accomplished by using chemical agents, physical agents, or radiation. Reuse of Treated Effluent – The industrial plant can reuse its own wastewater through recycling or after treatment or it can be used for irrigation . Auxiliary Operations

32. AUXILIARY OPERATIONS Carbon Adsorption – removes certain types of organic contaminants that are resistant to primary and secondary wastewater treatments. REUSE OF TREATED EFFLUENT – TERTIARY TREATMENT Granular Media Filters – removes organic and inorganic suspended solids and can be operated by gravity or pressure. FILTRATION

33. AUXILIARY OPERATIONS REUSE OF TREATED EFFLUENT – TERTIARY TREATMENT MEMBRANE SEPARATION Membrane separation techniques are used to: remove very fine particles from water to desalinate water to remove organics from water

34. AUXILIARY OPERATIONS REUSE OF TREATED EFFLUENT – TERTIARY TREATMENT MEMBRANE SEPARATION Ultrafiltration (UF) – a pressure-driven barrier to suspended solids, bacteria, viruses, endotoxins and other pathogens to produce water with very high purity and low silt density. Reverse Osmosis (RO) – demineralizes or deionizes water by pushing it under pressure through a semi-permeable membrane.

35. Wastewater Treatment Processes Preliminary Treatment Primary Treatment Secondary Treatment Tertiary Treatment Disposal

36. Preliminary Treatment • Purpose is to protect the operation of the wastewater treatment plant. • Remove from the wastewater any constituents which can clog or damage pumps, or interfere with subsequent treatment processes. They are designed to: 1. Remove or to reduce in size the large entrained, suspended or floating solids. 2. Remove heavy inorganic solids such as sand and gravel as well as metal or glass. 3. Remove excessive amounts of oils or greases.

37. Preliminary Treatment Processes • These consist of bars usually spaced three-quarter inches to six inches. Those most commonly used provide clear openings of one to two inches. • They are usually set at an angle of 45 to 60 degrees with the vertical. • The racks or screens may be cleaned either manually or by means of automatically operated rakes. Screening (Mechanical Screen)

38. Preliminary Treatment Processes Grit Chamber • Wastewater usually contains a relatively large amount of inorganic solids such as sand, cinders and gravel which are collectively called Grit • Grit chambers are usually located ahead of pumps or comminuting devices, and if mechanically cleaned, should be preceded by coarse bar rack screens. The detention period is usually between 20 seconds to 1.0 minute.

39. Preliminary Treatment Processes Skimming Tanks • A chamber so arranged that the floating matter like oil, fat, grease etc., rise and remain on the surface of the waste water. • The chamber is a long trough shaped structure divided up into two or three lateral compartments by vertical baffle walls. • A theoretical detention period of 3 minutes is enough. The floating matter can be either hand or mechanically removed.

40. Primary Treatment • Removal of settle-able organic and inorganic solids. • Approximately 25 to 50% of the incoming biochemical oxygen demand (BOD5), 50 to 70% of the total suspended solids (SS). • It may be considered sufficient treatment if the wastewater is used to irrigate crops that are not consumed by humans or to irrigate orchards, vineyards, and some processed food crops. • Primary sedimentation tanks or clarifiers may be round or rectangular basins, typically 3 to 5 m deep, with hydraulic retention time between 2 and 3 hours.

41. Primary Treatment Processes a. Sedimentation Tank – Primary Settling Tank

42. Primary Treatment Processes b. Coagulation – Secondary Settling Tank

43. Primary Treatment Processes c. Flocculation

44. How Primary Process Works • Sludge from the primary sedimentation tanks is pumped to the sludge thickener. More settling occurs to concentrate the sludge prior to disposal. • Primary treatment reduces the suspended solids and the B.O.D. of the wastewater. • Measurement and sampling at the inlet structure - a flow meter continuously records the volume of water entering the treatment plant - water samples are taken for determination of suspended solids and B.O.D. • From the primary treatment tanks water is pumped to the trickling filter for secondary treatment.

45. Secondary Treatment • Further treatment of the effluent from primary treatment to remove the residual organics and suspended solids. • Follows primary treatment and involves the removal of biodegradable dissolved and colloidal organic matter using aerobic biological treatment processes. • High-rate biological processes are characterized by relatively small reactor volumes and high concentrations of microorganisms compared with low rate processes. • The biological solids removed during secondary sedimentation, called secondary or biological sludge, are normally combined with primary sludge for sludge processing.

46. Common High-Rate Processes: Secondary Treatment Processes • Trickling Filters or Bio Filters • Rotating Biological Contactors (RBC)

47. Trickling Filters Secondary Treatment Processes • Consists of a basin or tower filled with support media such as stones, plastic shapes, or wooden slats. • Wastewater is applied intermittently, or sometimes continuously, over the media. Microorganisms become attached to the media and form a biological layer or fixed film. • Forced air can also be supplied by blowers but this is rarely necessary. The thickness of the biofilm increases as new organisms grow. Periodically, portions of the film 'slough off the media. • The sloughed material is separated from the liquid in a secondary clarifier and discharged to sludge processing.

48. Principle of Trickling Filters Secondary Treatment Processes

49. Rotating Biological Contactors (RBC) Secondary Treatment Processes • Fixed-film reactors similar to bio filters in that organisms are attached to support media. • In the case of the RBC, the support media are slowly rotating discs that are partially submerged in flowing wastewater in the reactor. Oxygen is supplied to the attached biofilm from the air when the film is out of the water. • Sloughed pieces of biofilm are removed in the same manner described for bio filters.

50. Tertiary Treatment • Employed when specific wastewater constituents which cannot be removed by secondary treatment must be removed. • Individual treatment processes are necessary to remove nitrogen, phosphorus, additional suspended solids, refractory organics, heavy metals and dissolved solids. De-chlorination and Disinfection Reverse Osmosis Ion Exchange Tertiary Treatment Processes

51. Tertiary Treatment Processes

52. Sewage Disposal • Disposal of wastewater and storm-water should preferably be considered only when reuse options are not feasible. Ultimate disposal of wastewater is either onto land or water (river, lake, ocean). • The general problem areas that are of concern in final disposal are pathogenic microorganisms (viruses, etc.), heavy metals and the presence of biologically resistant organic compounds, such as pesticides or insecticides which can find their way into water supplies. • There are three methods by which final disposal of wastewater - Surface Disposal, Subsurface Disposal, Disposal by Dilution.

53. Sewage Disposal Surface Disposal • Generally this is disposal by irrigation . This involves spreading the wastewater over the surface of the ground, generally by irrigation ditches. • This method is largely restricted to small volumes of wastewater from a relatively small population where land area is available and where nuisance problems will not be created. • It has its best use in arid or semi-arid areas where the moisture added to the soil is of special value.

54. Sewage Disposal Subsurface Disposal • Wastewater is introduced into the ground below its surface through pits or tile fields. • It is commonly used for disposal of settled wastewater from residences or institutions where there is only a limited volume of wastewater. • Little application for large scale use in municipalities.

55. Sewage Disposal Disposal by Dilution • The simple method of discharging wastewater into a surface water such as a river, lake, ocean, estuaries or wetlands. • The degree of pollution depends on the dilution, volume and composition of the wastewater as compared to the volume and quality of the water with which it is mixed. • However, in spite of the continued aerobic status of the receiving water, microbial pollution remains a health menace and floating solids in the wastewater, if not previously removed, are visible evidence of the pollution. • The presence of excessive amounts of nutrients can stimulate plant and algae growth in the receiving waters. This is of special concern in inland, enclosed waters such as lakes and ponds.

56. Sewage Disposal Disposal by Dilution

57. INDUSTRIAL WASTEWATER TREATMENT PRINCIPLES Industrial wastewater often contains various toxic substances. These substances are great harm to human health and environment, thus, it is necessary to develop comprehensive utilization and minimize the hazard.

58. There are 7 basic principles of industrial wastewater treatment that should be noticed 1. Choose non-toxic production technology to replace or improve the antiquated production process as well as eliminate or reduce the production of poisonous and harmful wastewater as far as possible in the production process.

59. 2. In the process of using toxic raw materials and producing toxic intermediates and products, adopt reasonable process and equipment , and implement strict operation and supervision to eliminate leakage and minimize the loss.

60. 3. Waste water containing highly toxic substances , such as some heavy metals, radioactive materials, high concentrations of phenol, cyanide and other wastewater should be SEPARATED from other wastewater to facilitate the treatment and recovery of useful materials.

61. 4. Some wastewater with large flow and low pollution, such as cooling wastewater, SHOULD NOT BE DISCHARGED INTO THE SEWER to avoid increasing the load on urban sewers and sewage treatment plants. This type of wastewater should be RECYCLED after proper treatment in the plant.

62. 5. Organic wastewater similar to urban sewage, such as food processing wastewater, sugar wastewater, and papermaking wastewater can be discharged into an urban sewage systems.

63. 6. Some toxic wastewaters can be biodegraded , such as phenol and cyanide-containing wastewater, can be discharged into urban sewers according to the allowable discharge standards after being treated in the factory, and further subjected to bio-oxidative degradation treatment by the sewage treatment plant.

64. 7. Toxic wastewater that are difficult to biodegrade should be treated separately and should not be discharged into urban sewage .