A Novel Water Pretreatment Approach for Turbidity Removal Using Date Seeds and Pollen Sheath

Mukheled Al-Sameraiy

doi:10.4236/jwarp.2012.42010

Abstract

Turbidity is a characteristic related to the concentration of suspended solids particles in water and has been adopted as an easy and reasonably accurate measure of overall water quality. The most widely applied water treatment processes, a combination of some or all of coagulation, flocculation, sedimentation and filtration to reduce or eliminate turbidity and improve water quality. In this research, proposed approach was adopted on the basis of applying two sequent treatments that used coagulation, flocculation and sedimentation processes under certain operating conditions of mixing speed, mixing time and settling time for each treatment. The environmentally friendly natural coagulants of date seeds (DS) or pollen sheath (PS) from local Iraqi palm was used in the first treatment and alum was used in the second treatment at their predetermined optimum doses to treat low ( NTU), medium ( NTU) and high ( NTU) ben- tonite synthetic turbid water. Experimental results clearly show that the proposed approach was superior in perform- ance in terms of residual turbidity compared with conventional approach using both of (DS) and (PS) natural coagulants in which it achieved a significant reduction in turbidity to less of 5 NTU that meeting WHO drinking water guidelines for all tested synthetic turbid water. Moreover, in some cases, it produced excellent water quality having residual tur- bidity less of 0.1 NTU. In addition to decrease the settling time to 30 minutes and minimize risks of alum dose required to 60%. These viable advantages are significant to current practices in advanced water treatment technologies such as reverse osmosis in cost, energy, effectiveness, safety and maintenance. So, it is recommended to consider proposed approach in this research work to be a novel pretreatment approach in advanced water treatment.

Highlights

Turbidity can be used to measure the performance of individual treatment processes as well as the performance of an overall water treatment system
Experimental results clearly show that the proposed approach was superior in performance in terms of residual turbidity compared with conventional approach using both of (DS) and (PS) natural coagulants in which it achieved a significant reduction in turbidity to less of 5 nephelometric turbidity unit (NTU) that meeting World Health Organization (WHO) drinking water guidelines for all tested synthetic turbid water
A set of experiments were carried out using jar test apparatus to investigate the effect of equal investigated dosages of each coagulant of (DS), pollen sheath (PS) and alum (A) in the range of 10 - 100 mg/L on the synthetic turbid water prepared at low, medium and high turbidities in terms of turbidity removal efficiency (R%)

Summary

Introduction

Turbidity can be used to measure the performance of individual treatment processes as well as the performance of an overall water treatment system. Common water treatment processes intended to remove suspended solids and reduce turbidity include: coagulation, flocculation, sedimentation and filtration [1]. Coagulation is the process of conditioning suspended solids particles to promote their agglomeration and produce larger particles that can be more readily removed in subsequent treatment processes. The process of coagulation is complex and may involve several different mechanisms to achieve “destabilization”, which allows particle agglomeration and enhances subsequent removal [2]. Flocculation is the process of bringing the destabilized particles into contact with one another to form larger “floc” particles. These larger particles are more readily removed from the water in subsequent processes [1]

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