The Central Pollution Control Board (CPCB) on January 31, 2022 has issued a circular for Inviting comments/suggestions on proposed draft "Environmental Guidelines for Compressed Biogas Plant (CBG)/Bio-CNG Plants"
The Highlights of the guidelines are as followed:
Handling of Solids Waste / Input material
1. Biodegradable solid waste/input material should be stored in such a manner that leachates formed do not get mix with any natural water body or stream.
2. If solids have any fire hazard possibility due fire extinguishing system should be set up.
3. Reject/undigested Solids should be disposed in accordance with MHW Rules and shall not be mixed with digested slurry for disposal.
4. Digested solid/sludge shall be used for producing FOM or Bio-compost. In case of Bio-compost, following shall be ensured:
a) The composting facilities of adequate size may be designed through expert institutions in the field.
b) The compost yard be provided with impermeable base with facility for collection of leachate and surface water run-off into lined drains leading to a leachate treatment and disposal facility.
c) The composting facility shall not be located within 300 m from the nearest dwelling and 100 m from any well or water course.
d) Necessary precaution shall be taken to minimise nuisance of odour, flies, rodents, bird menace and fire hazard.
e) The windrow area shall be provided with impermeable base. Such a base shall be made of concrete or compacted clay of 50 cm thick having permeability coefficient less than 10–7 cm/sec. The base shall be provided with 1 to 2 per cent slope and circled by lined drains for collection of leachate or surface run-off.
f) Leachate collection system shall be constructed. Leachate can be re-circulated in compost plant for moisture maintenance.
g) The end product compost shall meet the standards prescribed under Fertilizer Control Order notified from time to time.
h) The daily logbook record of the solid waste generated and bio-compost shall be maintained.
5. Groundwater monitoring
a) Location of piezometer- wells: Minimum at 2 places along the periphery of the bio-compost yard such that one is in the upstream of the Ground water flow direction and one in the downstream direction.
b) Hand pump: at least 30 meters depth, located within 500 meters to 1 Km from yards. Water quality of hand pump should be tested pre and post monsoon.
6. Approach Road to bio-compost yard: The entrance of the Bio-compost yard should be paved all-weather road for approach of vehicles.
7. Packaging and Labelling/Marking -The bio-compost or Bio manure shall be packed and labelled/marked properly.
8. Storage facilities for ready compost should be covered under shed having platform.
9. All other wastes such as iron filings, waste oils, transformer oils, batteries & other e-waste should be recycled using registered vendors.
II Solid Manure:
10. Solid manure should be stored in leachate-free way.
11. Solid manure can be used in farms with or without any value addition in conformity with requirements of Gazette Notification No. 2051 dated 14.072020 & No. 1972 dated 01.06.2021.
12. Solid manure may be converted to PROM (Phosphate Rich Organic Manure), Organic Potash fertilizer, organic silica fertilizer etc.
III Liquid Manure (Fermented Organic Manure):
13. Digested slurry while producing FOLM should be separated for solids as much as possible.
14. Use decanter, screw press, filter media or drying pit for separation of solids.
15. Liquid manure should be stored in leachate-free way.
16. Liquid manure can be used in farms with or without any value addition after confirming the stipulated quality requirements.
17. Liquid manure can be applied in farms after required treatment, depending on feed material and in conformity with requirements of Gazette Notification No. 2051 dated 14.072020 & No. 1972 dated 01.06.2021 and applicable effluent discharge standard. There shall be no adverse impact of application of digested biogas slurry on soil & environment.
18. Impermeable tank having total storage capacity of 15 days shall be provided for storing the liquid manure.
19. Any concurrent use of fertilizers (along with LOM) shall be done judiciously to avoid any superimposed effect.
20. In no case, the Liquid manure/effluent/leachate shall not be discharged into the drain/nallah/surface water bodies/channels/rivers.
21. The liquid concentrated nutrient rich fertilizer product after post processing shall be labelled and packed in containers for sale.
22. The daily logbook record of the Liquid manure produced by the unit shall be maintained.
IV Self-monitoring system
23. A flow-meter shall be installed at the wastewater/slurry generation/discharge line to quantify the slurry being generated for treatment. A PTZ camera shall be installed at storage tank and bio-compost area to monitor the bio-composting operation.
V Scrubber System:
24. CBG Plants use following types of scrubbers: a) Iron chelating based for H2S removal.
• Disposal of sulphur recovered from the process should be sold/disposed-off in correct manner as per rule.
• All waste streams coming from plant should be suitably treated & recycled/reused. In no case, effluent enters water body.
b) PSA for CO2 removal
• Exhaust gas being released to atmosphere in safe manner.
• Height of exhaust gas chimney to be raised to 3m above the roof level at least.
• Iron filings, silica gel should be disposed of through certified vendors.
c) Membrane for CO2 removal
• Membrane material disposal should be done through registered vendors only.
d) Water scrubber for CO2 and H2S removal.
• Effluent generated which is high in acids should be neutralized by using suitable method & then disposed-off after meeting the notified effluent discharge norms.
VI Other Requirements
25. Ambient air quality monitoring shall be regularly carried out.
26. Odour nuisance at down-wind direction on the boundary of processing plant shall also be checked regularly & accordingly necessary steps for its control shall be taken.
27. The Gensets shall comply with the latest Indian emission norms for Gas based Engines.
28. The biogas plants may be integrated with Solar PVs to make these plants cost economically viable
29. The CBG plant shall install flow meter at all water abstraction points for measuring water consumption & maintain logbook for the same.
It is requested that comments/suggestions, if any, may please be provided to CPCB by email in ([email protected], [email protected]) for finalization of said guidelines.
[Circular No. F.No.CP.99/6/2022-IPC-111-HO-CPCB-HO]
