**1. Introduction**

The main aim of the study is to assess the nature of waste water generated and to provide a realistic sustainable groundwater management by installing common

#### *Electrodialysis*

effluent treatment plant with zero liquid discharge system through implementation of membrane based ultra-filtration, reverse osmosis with recourse to recycling of bleaching and dying effluent at Kalikapur, West Bengal, India to save groundwater, environment and human health of a thickly populated area and 15 KM from Calcutta, a premier city of India. It revealed during study that the contamination level of surface water including canal water running in the cluster is highly contaminated. The waste water discharged into the nearby canal water is the main source of contamination as most of the units do not treat the waste water due to lack of treatment facilities in their own. The soil profile of the area is also degraded in the locality. Hence, the only way left behind is to treat the waste water to a level which can be reused in textile units through recycling. Membrane based treatment of waste water is found suitable in this circumstances to treat the toxic waste water as well as recycling of the treated water to the textile units to save groundwater paucity of the area. The water requirement in these industries is very high compare to any other industries in the world. The area Maheshtala, Chatta, Kalikapur, Mahishgot lie in South 24 Parganas district of West Bengal (**Figures 1** and **2**) between 10.450 N latitude to 75.900 E longitude having more than 1400 small and tiny bleaching and dying units as per Economic Survey (2014), Govt. of West Bengal where groundwater table is shrinking day by day as per SWID, Govt. of West Bengal survey.

**Figure 1.** *Map of Maheshtala region.*

**81**

*Toxic Effluent Treatment by Membrane Based Ultrafiltration and Reverse Osmosis…*

The overall mean concentrations of different physico-chemical parameters studied (pH, TDS, BOD, COD, NO3, hardness, Fe, F, Pb, Cd, Cr and Na) showed distinct seasonal trend in the following order of variation: pre-monsoon (April, May and June) > monsoon (July, August September and October) > post-monsoon (November, December, January and February)(P < 0.05). The physicochemical profile of waste water reflects that highest concentrations of both metals and organic loading are associated with the quantum and quality of bleaching and dyeing effluents released from the units studied. For the Maheshtala textile units the manufacturing processes like cutting and stitching activities of cloths start in the pre-monsoon season whereas the bleaching and dyeing processes starts in June continues till August stretching pre-monsoon to monsoon to meet the demand in festival season, which have significant implications in both metal and organic loading in the wastewater effluents. The present findings on high metal concentration and deteriorated physicochemical parameters are similar in other studies on textile

There appeared significant differences in metal concentrations in wastewater reflected in the following order: Na > Fe > Cr > Pb > Cd (P < 0.05). The metals in wastewater find their sources in the chemicals (like sodium hydrochlorides, sodium hydro-sulphites, optical brightening agent, caustic soda etc.) and dyes (mordant dyes, azo dyes, disperse dyes, vat dyes, indigo dyes etc.) used for the wet processing

The heavy metal pollution index (HPI) for the wastewater studied is estimated as 926 which exceeds the critical level of 100 for drinking water as determined by Hakanson model [4] by about 9 folds. The study has shown similar HPI value for water of Jamuna river (near Delhi) obtained by [5, 6] following the same model (1492). Again the metal index (MI) in case of the studied wastewater is 4.68 which far exceeds than that of the threshold level of 1 for drinking water as prescribed by Hakanson model [4]. While assessing the water quality index (WQI) the results show that the wastewater poses severe potential ecological/health risk during all the seasons being maximum threat (WQI PRM-16) followed by (WQI M-19) and the minimum in post-monsoon (WQI PSM-31). According to Hakanson model (in the scale of 0–100) the present risk falls under the severe category in pre-monsoon and monsoon and

While comparing with the permissible limits for relevant parameters in case of wastewater discharge as per IS: 10500 (2012) it was observed that the values of the physico-chemical parameters and metals in the present study exceeded the respec-

All the physico-chemical parameters and metal concentrations in wastewater are very much higher than the permissible limits for drinking water of BS: 10500 (2012) and WHO (2003). These indicate that wastewater is critically contaminated compared to limits provided for drinking water. It finds conformity with observations of [7]. Due to higher level of TSS, TDS, BOD, COD and presence of very high concentrations of Pb, Fe and Na the wastewater becomes highly contaminated and often toxic, and there remains high chance of transfer of metals to soils and subsequently to crops, vegetables and fruits when irrigation contamination occurs due to advertent irrigation or inadvertent flooding of agricultural fields [8]. Wastewater also contaminates the water ways due to its direct discharge to the Chatta canal and damage aquatic ecosystem of canal, pond, watershed and ground water due to

critical in post monsoon with an annual average WQI being 22.

infiltration as shown by similar study conducted by [9].

*DOI: http://dx.doi.org/10.5772/intechopen.92812*

**2. Assessment of waste water quality**

industries waste water [1–3].

of textiles.

tive limits.

**Figure 2.** *Map of Chatta Kalikapur.*

*Toxic Effluent Treatment by Membrane Based Ultrafiltration and Reverse Osmosis… DOI: http://dx.doi.org/10.5772/intechopen.92812*
