Fighting against POLLUTION to Save Environment
Fighting against POLLUTION to Save Environment
Encology ,10 (8), 8-12, January, 1996.
Examine the present mode of conveyance up to the outfalls; if it is underground sewer, check for chocking, any cleaning needed - identify sewer maintenance needs. If it is an open channel, see its state and examine if cement lining is required. Also examine if underground sewer is required.
Examine the topography of the Estate and check whether more than one outfall could be economical if underground sewers are adopted.
Examine if collection by tankers would be economical (advantages: immediate implementation, useful if industries are located at considerable distance; prohibitive cost of collection avoided).
Categories of industries having been identified, production process/technology known, list from UNIDO / UNEP publications relevant to waste minimisation options - Recycle, recovery or reuse options. Discuss practicability of options with the entrepreneurs. Report outcome.
Approach to motivate the entrepreneurs for adoption.
Conduct laboratory scale treatment studies on the terminal wastewater, physical, chemical, biological - determine the:
Table 2 : Basis for Wastewater Categorisation
| Chemical | Reaction | wwc | Explanatory | Pretreatment | Acceptability |
|---|---|---|---|---|---|
| High SS | Highly settlable | A | Non-Toxic solids highly settleable | NP | Acceptable |
| High SS | Colloidal needs | A | Non-Toxic solids settleable after | NP | Acceptable |
| Organics | Highly biodegradable | A | Org. Solids in solution and/or suspension, highly biodegradable | NP | Acceptable |
| Organics | Slowly | A | Org. solids in solution and/or suspension, slowly biodegradable, e.g., benzene series | NP | Acceptable |
| In-organics | Acid | B | Mineral acids produced or used in excess | N & SEP | Acceptable on neutralisation |
| In-organics | Alkali | B | Alkalies produced or used in excess | N & SEP | Acceptable on neutralisation |
| High TDS | Precipitable | B | Raw or product materials are soluble in water | CP & SEP | Acceptable on precipitation |
| High TDS | Membrane separation | C | Highly soluble solids need membrane separation | NIP | Require expensive collective treatment using membrane separation |
Note: NP: No Pretreatment, N & SEP: Neutralisation & Solid Separation, NIP: No Individual Pretreatment, CP & SEP: Chemical Precipitation & Solid Separation
Table 3 : Treated Effluent Quality Standards for CETP
| Parameter | Concentration in mg/l, except pH & Temperature | Into inland surface water | On land for irrigation | Into marine Coastal areas |
|---|---|---|---|---|
| pH | 5.5-9.0 | 5.5-9.0 | 5.5-9.0 | |
| BDD 20°C | 30 | 100 | 100 | |
| Oil & Grease | 10 | 10 | 20 | |
| Temperature | Shall not exceed 45°C in any section of the stream within the effluent outlet | 45°C at the point of discharge | 45°C at the point of discharge | |
| Suspended solids | 100 | 200 | a. For process wastewater 100 b. For cooling water effluents 10% above total suspended matter of influent cooling water |
|
| Dissolved solids (inorganic) | 2100 | 2100 | - | |
| Total residual chlorine | 1.0 | - | 1.0 | |
| Ammonia nitrogen (as N) | 50 | - | 50 | |
| Total Kjeldahl nitrogen (as N) | 100 | - | 100 | |
| COD | 250 | - | 250 | |
| Arsenic (as As) | 0.2 | 0.2 | 0.2 | |
| Mercury (as Hg) | 0.01 | - | 0.01 | |
| Lead (as Pb) | 0.1 | - | 1.0 | |
| Cadmium (as Cd) | 1.0 | - | 2.0 | |
| Total Chromium (as Cr) | 2.0 | - | 2.0 | |
| Copper (as Cu) | 3.0 | - | 3.0 | |
| Zinc (as Zn) | 5.0 | - | 15 | |
| Selenium (as Se) | 0.05 | - | 0.05 | |
| Nickel (as Ni) | 3.0 | - | 5.0 | |
| Boron | 2.0 | 2.0 | - | |
| Percent sodium | - | 60.0 | - | |
| Cyanide (as CN) | 0.2 | 2.0 | 0.2 | |
| Chlorine (as Cl) | 1000 | 600 | - | |
| Fluoride (as F) | 2.0 | - | 15 | |
| Sulphate (as SO4) | 1000 | 1000 | - | |
| Sulphide (as S) | 2.8 | - | 5.0 | |
| Pesticides | Absent | Absent | Absent | |
| Phenolic compounds (as C6H5OH) | 1.0 | - | 5.0 |