Section 83 in Assam Notified Urban Areas (Other than Guwahati) Building Rules, 2014
83. Re-use of Recycled/Waste Water.
(1)Roof top rain water may also be collected and discharged by filtration directly into a well. Diameter of such pipes shall not be less than 75 mm, one such pipe shall be provided for every 100 sq.m.of roof area.(2)Every group housing scheme/apartment and commercial complexes/institutional buildings shall be provided with installation of system of recycling of wastewater from bathrooms and kitchen sinks (excluding water closets) The final treatment plant shall recycle water which shall be reused for purposes other than drinking such as gardening, landscaping, and washing of roads/pathways and so on. Accordingly the space for a wastewater treatment plant is mandatory to be proposed in the layout and constructed as per the approved norms and specifications in case of,-(a)residential layouts, areas admeasuring 4,000 sq.m. or more;(b)group housing/apartment building if the area admeasures 2,000 sq.m. and above or if the consumption of water is 20,000 liters per day or if it is a multi-storied building with 20 or more apartments;(c)commercial complexes / institutional / hotel and lodges/industrial buildings etc. if the built-up area is 1,500 sq.m. and more or water consumption is 20,000 liters per day;(d)hospitals/nursing homes with 40 or more beds.(3)Every group housing schemes/apartment etc. shall make provisions of facilities and infrastructure to recycle the wastewater(Grey Water) from bath rooms and kitchen sinks in following manners:-(i)each building shall have a separate downward pipeline to collect waste water from bath and wash basins and the collected waste water shall be treated adequately by organic or mechanical recycling and taken to a Settling tank for onward pumping to the exclusive overhead tank or to a separate collection unit of over head tank for exclusive use of toilet flushing through cisterns. The excess waste water not reused for toilet flushing shall be suitably connected to the rain water recharge structures for ground water recharge.Explanation: For the purposes of these rules in regard to recycling systems are concerned, any other modifications, additional structures, alternative designs furnished by the applicant shall be considered for approval, if it conforms to recycling concept to the satisfaction of the competent authority for building plan approval;(ii)the tank shall be large enough to hold twice the expected daily flow of wastewater plus 40% to allow sludge accumulation and surge loading. One type of settling tank well suited for grey water treatment is a septic tank with aeration facility. (area requirement approx. 8 sq.m per m3 of wastewater)(iii)two chemicals, namely, chlorine and iodine may be used to disinfect water. Organic material in grey water may combine with chlorine reduce amount available for disinfection. Filter or settling tank is advisable before disinfection;(iv)type of filter required depends on amount of grey water to be filtered and type of contaminants present, viz, simple drain filter, activated charcoal, cellulose or ceramic cartridge, slow sand or multimedia filters etc, could be used based on specific requirement;(v)grey water for reuse to be collected in separate unit and provision is made for a separate overhead tank for storage of recycled grey water for use of toilet flushing and gardening/landscaping purpose only;(vi)lying of dual pipe lines is necessary, viz., one for carrying potable water and other for carrying grey water duly marked in orange colour and laid separately for the ease of identifying the pipe carrying grey water;(vii)if separate point to draw water for gardening, landscaping and washing is provided, it shall be provided with an adequate warning that the water is not fit for drinking.
