About Effluent Treatment Plant
When Lead Acid Batteries are replaced, they contain spent acid with some lead dissolved in it. These used batteries are sold in the open market to lead recyclers where they are drained before being put into the process of recycling. Further in many units, plastic containers of the batteries, after cutting and opening, are washed to remove any lead in them. The drained acid alongwith any washing effluent of the plastic scrap comprises of the effluent that needs treatment at the Effluent Treatment Plant(ETP). This ETP is also commonly called Acid Neutralisation System.
If unchecked, these untreated effluent will seep in to land and would lead to soil contamination, pollution in ground water table and their runoff may also lead to pollution of nearby eater sources. Hence, their proper treatment before disposal is necessary.
Characteristics of Effluent before and after Treatment
3.0 - 4.0
6.5 - 8.5
600 - 800 mg l
30 - 40 mg l
(However, where only spent acid is fed into the ETP, sludge generated is in the form of sodium sulphate or calcium sulphate with lesser quantities of lead will be dewatered and stored as hazardous waste instead.)
Description of Plant
An Effluent Treatment Plant for lead recycling units can be designed as a Batch Type unit or as a Continuous Unit. This mainly depends on the quantity of effluent to be handled. While smaller quantities can be treated in batches, quantities above 10 kl/day are to be treated in Continuous Operating Units.
Batch Type Unit
Continuous Treatment Unit
Treated effluent is passed through a series of Polishing Filters (a set of Pressure Sand Filter & Activated Carbon Filter) before disposal. This improves upon the characteristics of the treated effluent.