Table 9.

Selected physicochemical parameters of treated tannery wastewater after RSM application.

Parameter	Unit	Result *	Effect (%) **
pH	-	8.5 ± 0.1	Non-significant
Total Dissolved Solids	mg/L	19,590 ± 1960	↑7.3
Total Solids	mg/L	20,560 ± 2060	↑4.4
Suspended Solids	mg/L	30.0 ± 3.0	↓97.9
Color	mg Pt/L	80 ± 16	↓99.3
Chemical Oxygen Demand	mg O2/L	1740 ± 260	↓86.1
Total Organic Carbon	mg/L	950 ± 140	↓80.5

* parameter value ± the measurement uncertainty for an extension factor k = 2, ** Effect = $\frac{\left(C1-C2\right)\times 100\%}{C1}$ (for SS, color, COD, and TOC) and ** Effect = $\frac{\left(C2-C1\right)\times 100\%}{C1}$ (for TDS and TS), where c₁-concentration in raw tannery wastewater, c₂-concentration in treated wastewater, ↑-increase in the parameter value, ↓-decrease in the parameter value.