Alom Poly Extrusions implemented a new internal sewerage system at UML industrial complex using the Alcorr DWC PE piping system. The project was completed within a remarkably short period without affecting the factory operation for a single working day.
Universal Machines (UML) is an industrial complex located within the overwhelmingly populated city of Howrah. The city is on the west bank of River Hooghly and connected with Kolkata by two river bridges. The city is well known for its drainage and water logging problems during monsoon. The flows through the underground drainage network remain stagnant during high tide period and the core urban clusters remains inundated till the water level in receiving river recedes. The problem is even more acute for the numerous industrial complexes located within the heart of this thickly populated township.
The internal drainage systems of those complexes are extremely inadequate and can not even properly converge to the existing municipal drainage system leading to the River Hooghly. Such inadequacies cause persistent water logging at factory complexes for prolonged periods even after recession of the water level of the receiving river. These haphazardly grown industrial complexes in the heart of city are thriving for a solution to such techno-economical impasse because construction of conventional underground drainage network within their complexes is time consuming and needs total closure of all activities which shall eventually collapse their business perspective.
UML Industrial Complex
UML is an industrial complex suffering for years from such acute infrastructural problem leading to unbearable economical losses and pollution hazards during monsoon. The complex is housed with 33 factories with multifarious types of manufacturing activities.
The entire cluster covers more than 3 hectare of developed land within core area of Howrah city. The complex has around 3 km of internal roads and all the aforementioned manufacturing units are installed alongside of said arteries. The road width varies from 8 m at the entrance location and the same is 6 m at its extremities.
For the solution of acute internal drainage congestion problem, various system alternatives were considered by the clients. Several modalities as below were studied for construction of a full proof system and integration of the same with the municipal sewer:
- Construction of brick masonry surface drainage network
- Installation of conventional non-pressure RC piping system
- Installation of GSW sewerage network.
Neither of the alternatives seemed to be the feasible option. The simple reason was that the internal roads could not be closed for successive days for the construction purpose for it would have severely affected the incoming and outgoing heavy commercial vehicle operations – an imperative necessity to run the factories.
With this technical impasse, the UML management approached Alom Poly Extrusions (APEL), the manufacturers of modern ‘structured wall plastic piping system’ in India for a viable solution of the persistent problem.
The project
The APEL management realised that this shall be the best opportunity to showcase the applicability of their frontier technology revolutionary product Alcorr DWC PE piping system and decided to perform an in-depth case study and subsequent pilot project implementation in the matter.
The product and system
Alcorr Class SN 8 structured double wall (non-smooth external annular corrugated wall and smooth internal wall) polyethylene (Alcorr DWC PE) piping system for non-pressure underground sewerage and drainage applications.
Alcorr DWC PE piping system is manufactured using high density polyethylene material. The pipe is corrugated on the outside and smooth inside which allows for great load bearing capacity and smooth flow of fluids inside. It is coupled using an elastomeric rubber sealing ring and push-fit couplers that ensure 100 per cent leakage protection.
This product is ideal for non-pressure sewerage and drainage applications and is regularly being used globally. Advantages This particular system outscores the conventional sewerage piping systems in all aspects:
Structural integrity: The overall attributable design load for Alcorr DWC PE piping system shall be remarkably lesser than that of conventional rigid pipes because of its inherent flexibility. Therefore, expensive concrete cradle beddings are not necessary. This saves on installation time and ancillary installation expenditures. Since such plastic pipes are structurally safe at much lower cushion depth, the required installation time and expenditure there-off is further minimised.
Hydraulic capability: Highly smooth inner wall of Alcorr DWC PE piping system has very low roughness (Manning’s ‘N’ = 0.010) in comparison with any category of conventional rigid pipes and therefore the same sized pipes can accommodate much higher flows at identical gradient. In other words, for a particular discharge, lower sized pipes can be used in comparison with conventional rigid pipe keeping the prescribed gradient identical. Such hydraulic advantage leads to time and financial savings as well.
Material life: The conventional concrete non-pressure pipes have a life expectancy of 20- 30 years where as Alcorr DWC PE piping system lasts at least for 100 years.
Chemical inertness: The material property of Alcorr DWC PE pipes ensures inertness to all the sewage ingredients and therefore reduces adherence to the internal surfaces of the piping system to negligible amounts. This is a huge advantage in terms of maintenance perspective. Such behaviour ensures almost constant ‘N’ value throughout the material life. In case of conventional rigid pipes the ‘roughness coefficient’ changes periodically because of deposition of solids on inner surfaces which eventually reduce the capacity of the total network. Other features: Its lightness and simple jointing procedure allows for user-friendly application with minimum installation time involving very little manual labour deployment.
Implementation of the pilot project
The hydraulic design of the combined sewer network was computed on the basis of available IFD curve for the designated rainfall frequency pertaining to the location considering the relevant Manning’s ‘N’ value related to the Alcorr DWC PE piping system and in accordance with the manual on sewerage and sewage treatment, CPHEEO, Ministry of Urban Development, Government of India. Accordingly, the salient features of the pilot scheme comprised: 250 mm, 400 mm and 600 mm ID DWC PE piping system.
The job was implanted by ensuring systematic and phased discontinuation of traffic flows in small road segments for very short periods. The client in their certification confirmed: "we have reasons to believe that through conventional methodology, completion of the schemes would never have been possible to save except total termination of activities for a prolonged period and may have even required restructuring the campus."
In haphazardly developed industrial complexes located within the core clusters of old metropolis, rehabilitation of internal sewerage system with conventional rigid pipes is extremely difficult and time consuming. This is because of acute space restriction and congestions resulting from continual business activities. This project ensures that instead of conventional rehabilitation, if the frontier technology products such as Alcorr DWC PE pipes are adopted, the targeted refurbishment and can be achieved in very short time period without disturbing the business activities and providing a durable solution for the future.
Applicable codes
EN 13476-3 plastics piping systems for non-pressure underground drainage and sewerage structured wall piping systems of polyethylene (PE) Part 3: specifications for pipes and fittings with smooth internal and profiled external surface and the system, Type B.
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