Abstract
This study investigates hybrid pilot scale treatment system for Dairy cattle
farm wastewater (DCFW) obtained from the Rami Farm located in the Balenda
town, Barzan, Erbil, Iraq, integrating 24-hour sedimentation process, coagulation,
and biofiltration. The primary objective was to conduct a comparative assessment
of three coagulants: zeolite (Z) and Moringa oleifera seeds (MO) as natural
alternatives and aluminum sulfate (alum) as a conventional coagulant. Five
different concentrations of each coagulant were applied: Z at 0.3, 0.4, 0.5, 0.6,
and 0.7 g/500 ml; MO at 0.1, 0.2, 0.3, 0.4, and 0.5 g/500 ml; and Alum at 1.0, 1.5,
2.0, 2.5, and 3.0 g/500 ml, and three replications to identify the optimal dose
based on maximum removal efficiency. The supernatant from each coagulation
treatment sample was subsequently filtered using low cost, environmentally
friend, physically activated rice straw (RS) to assess the removal efficiency of the
filtration stage. The performance at each treatment stage was evaluated through
the removal efficiencies of key physicochemical parameters, including chemical
oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended
solid (TSS), total dissolved solid (TDS), electrical conductivity (EC), total
Phosphorus (TP), total Nitrogen (TN) and total Organic Carbon (TOC).
Over the duration of a 24-hour initial sedimentation period, the upper
limits of contamination indicators in DCFW were considerably reduced. Important
water quality parameters as COD, BOD, TSS, TP, TN, and TOC levels remained
significantly over permitted discharge limits despite this initial decline.
The obtained data from treatment process showed that the type and
quantity of the coagulant had a significant impact on the coagulation removal performance. The optimum coagulant dosage was obtained to be 0.7 g/500ml for Z, 0.5 g/500ml for MO seed and 2.5 g/500ml for A.Results indicated that Alum (A) at 2.5 g/500ml followed by RS filtration achieved the highest removal of COD up to 78.59%, BOD 82.88%, and TP 75.08 %, owing to its strong hydrolysis and precipitation capabilities. In contrast, Z at 0.7 g/500ml demonstrated superior performance in TN 75.99% and TOC 73.84% removal, being associated to its porous structure and high cation exchange capacity, which promote organic carbon retention and ammonium adsorption. MO seed coagulant achieved intermediate removal efficiencies for all treated parameters, and its performance was continually surpassed by either A or Z in each respective parameter.Overall treatment efficiency was improved by the extra elimination of remaining suspended and dissolved contaminants provided by the last step of RS filtration. The substantial differences (p≤0.05) between coagulants and concentrations, namely for COD, BOD, TP, TN, and TOC, were validated by statistical analysis using one-way Anova and Duncan’s multiple range test. Under ideal circumstances, the efficacy of natural coagulants combined with RS filtration is equivalent to that of traditional chemical coagulants, making it a viable and affordable option for decentralized DCFW treatment
