WATER & EFFLUENT TREATMENT
Effluent treatment since 1982
Many industrial processes produce effluent which is either too acidic or too alkaline to be safely discharged to drain , a piece of process control plant which is intercepts this and corrects the pH to make it safe to discharge to drain is called a pH neutralisation system .
Automated Water & Effluent Ltd , since thier foundation in1982 , have supplied equipment and systems specifically for the pH neutralisation of waste water from industrial processes .
Working with a market leading supplier in the surface finishing sector they were approached to design , build and commission a pH neutralisation system . Their customer is one of the leading providers of surface finishing solutions into the marine , rail and architectural sectors . As the customer is a supplier of numerous services , the waste-water treatment system will in turn be neutralising the pH from numerous processes , which include : -
Chemical pre-treatment De-ionised water regeneration Multi-stage coarse & fine rinse water
Principle Of Operation
The system has been designed to neutralise the pH of the customers effluent making it compliant with the local legislation and adhering to their consent to discharge agreement . With the waste water from each of the customers industrial processes , including waste water from the rinses , the regeneration of the de-ionised water beds and the pre-treatment baths - all being collected into an underground sump .
Their customer specified that the pH neutralisation system should be skid mounted to make sure that it can be easily moved to the desired location . All the systems that AWE supply , including the system for our customer are supplied : -
Complete with a full suite of technical drawings to make mechanical integration as simple as possible .
Ready , wired and tested to ensure that the onsite electrical engineers can quickly and easily bring the system into operation .
When purchasing a system from AWE they offer their customers an optional commissioning visit from one of their service engineers - the customer went ahead with this , which included : -
A commissioning visit from AWE Ltd service engineers to ensure that the pH neutralisation system is calibrated and working in the manner specified by the customer .
The waste-water to be pH corrected is transferred to the correction tank using air operated double diaphragm pumps . Using a series of level controllers and sump mounted low level float switches the control panel calls for the solenoid valves . These in turn control the incoming air flow to the pneumatically operated double diaphragm pumps which transfer the waste-water to the mixing tank .
The pH electrode mounted inside the mixing tank works with the pH controller to call for either the acid dosing pump or alkaline dosing pump to neutralise the pH in the waste-water . The addition of the top mounted high mixer improves the efficiency of the chemical reagent reducing the required contact time for neutralisation .
By carefully calculating the contact time required at the extremes of the incoming pH scale the volume was calculated to ensure that the pH neutralisation system can return the neutralised effluent to drain through a cascading sump arrangement .
Pallet / Skid Mounted pH Neutralisation System
The customer ’ s core preference was for a complete solution to their pH neutralisation which could easily be positioned into place and simply integrated into their existing processes , including drawing the waste water up into a treatment tank from a sump .
AWE Ltd provided the customer with a single fabricated solution which could be lifted using the skids of a fork lift truck for easy transportation to site , and so that it could be simply manoeuvred to the desired site location .
The fabricated solution was destined to be located outside . To protect the instruments from the environment all the fabricated enclosures containing the control panel , instruments , air operated double diaphragm pumps and the chemical dosing pumps were provided with transparent covers to protect them from the elements .
All the wired connections and external electrical items such as the top mounted alarm beacon and all electrical glands have been supplied to IP65 specification , which ensures that they are suitable to be located outside .
The pH correction tank was fabricated in chemically resistant polypropylene and also mounted onto the skid mounting area - allowing the whole unit to be lifted from a fork lift as well easily manoeuvred for final positioning . Access to the tank is via a half removable lid complete with a mixer bridge to support the high speed mixer .
The enclosure containing the control panel was fabricated as a separate chamber isolating it from the lower enclosure , which contains the duty & assist air operated double diaphragm transfer pumps .
The chemical containers were located in another enclosure located at the opposite end of the skid mounted unit . This skid mounted enclosure includes 2 separate bunded areas - each designed to contain a 25 litre chemical container with a capacity of ~ 35 litres - to contain the contents of each of the chemical containers in the event of a spill or leak .
The hoses connecting the air operated transfer pumps and the chemical dosing pumps have been supplied as double confined dosing tube to ensure containment in the event of the tubing becoming compromised .
When the waste water has been pH corrected , the customer requested that this is discharged into a cascading sump
46 APRIL 2021 read online : www . surfaceworld . com