Water Quality Index Model Application in Evaluation of Groundwater Quality in a Waste Treatment Facility

Figures & data

Figure 1. Geological map of the study area. Three geological features showing the different types of rocks and surficial deposits in the study area.

Figure 2. Map showing the sampling locations. A diagram showing the location of Shama Municipality, the waste treatment plant, and three sampling points.

Table 1. Relative weights of groundwater quality parameters.

Parameters	Weight (ωi)	Relative weight (Wi)	WHO guideline value (2011)
Temperature (^oC)	1.00	0.01	25.00
pH	3.00	0.03	8.50
Turbidity (NTU)	5.00	0.06	5.00
EC (µS/cm)	3.00	0.03	1000.00
TDS (mg/L)	5.00	0.06	500.00
TH (mg/L)	3.00	0.03	500.00
Na^+ (mg/L)	3.00	0.03	250.00
Ca^2+(mg/L)	3.00	0.03	75.00
Mg^2+(mg/L)	3.00	0.03	50.00
NH4^+(mg/L)	5.00	0.06	1.50
NO3^− (mg/L)	5.00	0.06	5.00
Cl^− (mg/L)	5.00	0.06	250.00
SO4^2- (mg/L)	5.00	0.06	500.00
Fe (mg/L)	1.00	0.01	0.30
Zn (mg/L)	5.00	0.06	5.00
Cu (mg/L)	5.00	0.06	2.00
As (mg/L)	5.00	0.06	0.01
Pb (mg/L)	5.00	0.06	0.01
K^+ (mg/L)	3.00	0.03	55.00
F^− (mg/L)	5.00	0.06	1.50
	∑ 78.00

Table 2. Descriptive statistics of groundwater physicochemical parameters.

Parameters	BH1	BH 2	BH3	Range (overall)	CV (%)	WHO guideline
	Mean ± SD	Mean ± SD	Mean ± SD
Temperature (^oC)	26.87 ± 1.07	28.87 ± 0.79	25.66 ± 0.25	25.20–30.00	5.66	25.00 °C
pH (unit)	7.19 ± 0.16	7.27 ± 0.01	7.01 ± 0.01	7.00–7.60	1.99	6.5–8.5
Turbidity (NTU)	1.05 ± 0.02	1.85 ± 0.01	1.25 ± 0.08	1.02–1.88	25.1	5.00
EC (µS/cm)	2037.58 ± 1.87	3933.25 ± 2.48	2084.37 ± 2.69	2034.40–3936.00	33.10	1000.00
TDS (mg/L)	1225.83 ± 5.78	2358.00 ± 1.44	1190.48 ± 0.30	1220.00–2360.00	32.17	500.00
COD (mg/L)	10.20 ± 0.14	15.21 ± 0.14	10.60 ± 0.14	10.00–15.40	19.11	10.00
TA (mg/L)	132.96 ± 0.82	112.25 ± 0.98	117.60 ± 0.13	111.00–134.00	7.19	120.00
TH (mg/L)	434.56 ± 0.63	1343.00 ± 2.16	450.47 ± 0.22	434.00–1345.00	57.56	500.00
Na^+ (mg/L)	120.53 ± 0.13	210.47 ± 0.14	125.47 ± 0.14	120.40–210.00	27.32	200.00
Ca ^2+ (mg/L)	340.30 ± 0.14	712.62 ± 2.03	360.43 ± 0.21	340.00–715.00	36.54	75.00
Mg ^2+ (mg/L)	94.25 ± 0.13	633.62 ± 2.16	100.40 ± 0.17	94.00–637.00	92.21	50.00
NH4^+ (mg/L)	0.07 ± 0.01	0.06 ± 0.01	0.02 ± 0.01	0.01–0.08	122.82	1.50
K^+ (mg/L)	5.03 ± 0.01	7.03 ± 0.01	5.38 ± 0.01	5.01–7.05	15.13	55.00
NO3^− (mg/L)	0.05 ± 0.01	1.35 ± 0.02	0.07 ± 0.01	0.04–1.38	15.13	5.00.00
Cl^− (mg/L)	497.37 ± 1.24	1482.25 ± 2.38	500.22 ± 0.14	495.00–1486.00	56.47	250.00
F^− (mg/L)	0.46 ± 0.01	0.51 ± 0.01	0.48 ± 0.01	0.45–0.54	4.74	1.50
SO4^2- (mg/L)	100.26 ± 0.18	123.30 ± 2.84	110.30 ± 0.18	100.00–128.00	8.72	500
PO4 ^3- (mg/L)	0.68 ± 0.09	0.55 ± 0.02	0.61 ± 0.08	0.50–0.80	14.51	2.50
HCO3^− (mg/L)	1.34 ± 0.01	1.07 ± 0.01	1.22 ± 0.02	1.05–1.36	9.18	600.00
Fe (mg/L)	0.03 ± 0.01	0.07 ± 0.02	0.03 ± 0.01	0.03–0.08	39.23	0.30
Zn (mg/L)	0.03 ± 0.01	0.37 ± 0.01	0.06 ± 0.01	0.02–0.38	100.12	5.00
Cu (mg/L)	0.15 ± 0.01	0.34 ± 0.01	0.21 ± 0.01	0.14–0.36	34.49	2.00
As (mg/L)	<0.01 ± 0.00	<0.01 ± 0.01	<0.01 ± 0.00	0.001–0.005	49.47	0.01
Pb (mg/L)	<0.01 ± 0.00	<0.01 ± 0.01	<0.01 ± 0.00	0.013–0.06	55.43	0.01

aBH1 = Area located 1 km away from WTF; BH2 and BH3 = effluent discharge and administration areas respectively of the WTF; CV = coefficient of variation.

Table 3. Analysis of variance (ANOVA) test results.

Variables	Sum of squares	Mean square		F-ratio	Ƿ-value
		Bt. groups	Wt. groups
pH	1.4629	0.420	0.009	47.151	0.000
Temperature	169.068	63.161	0.620	101.95342	0.000
Turbidity	8.636	4.218	0.003	10,459.291	0.000
EC	56112903.868	28,056,256.598	5.661	4,955,270.461	0.000
TDS	19405256.655	9,702,217.946	11.895	815,647.691	0.000
COD	373.948	186.241	0.021	8764.294	0.000
Total alkalinity	5383.228	2672.296	0.559	4772.420	0.000
Total hardness	12,977,020.618	6,488,451.098	1.716	3,780,597.872	0.000
Ca^2+	2,104,539.678	1,052,269.838	1.408	747,125.797	0.000
Mg^2+	4,602,336.910	2,301,168.455	1.576	1,459,850.350	0.000
HCO3^−1	0.864	0.431	0.000	1431.511	0.000
Nitrate	26.583	13.292	0.000	44,305.166	0.000
NH4^+	0.065	0.031	0.000	899.372	0.000
Cl^−	15,474,879.910	7,737,439.955	2.414	3,204,774.338	0.000
SO4^2-	6703.477	3257.738	2.717	1198.704	0.000
PO4^3-	0.572	0.105	0.005	20.290	0.000
Fe	0.023	0.009	0.000	161.000	0.000
Zn	1.728	0.869	0.000	8162.747	0.000
Cu	0.471	0.233	0.000	3381.000	0.000
As	0.000	0.000	0.000	32.200	0.000
Pb	0.000	0.000	0.000	38.150	0.000
Na^+	122,706.408	61,352.531	0.019	3,144,530.849	0.000
F^−	0.037	0.015	0.000	165.097	0.000
K^+	55.849	27.425	0.002	10,612.306	0.000

Bt = between treatment; Wt = within treatment; Ƿ = significant level

Table 4. Bacteriological characteristics of groundwater samples.

Location	Mean microbial count (CFU/100 ml)		Range of microbial count (CFU/100 ml)
	total coliform	E-coli	total coliform	E-coli
BH1	0.0	0.0	0.0	0.0
BH2	20,100.0 ± 1.2	11,800.0 ± 1.0	20,000.0–20,400.0	11,600.0–11,900.0
BH3	30,200 ± 2.3	25,000.0 ± 2.2	30,000.0–30,600.0	24,500.0–25,500.0
WHO standard	0.0	0.0	0.0	0.0

CFU = Colony Forming Unit; BH1 = Area located 1 km away from WTF; BH2 and BH3 = effluent discharge and administration areas respectively of the WTF.

Table 5. Water Quality Index of groundwater.

	Q*Wi at BH1			Q*Wi at BH2			Q*Wi at BH3
Parameters	Mean	Min	Max	Mean	Min	Max	Mean	Min	Max
Temperature (^oC)	1.37	1.33	1.48	1.48	1.43	1.53	1.29	1.29	1.31
pH (unit)	3.25	3.20	3.43	3.28	3.28	3.30	3.17	3.16	3.18
Turbidity (NTU)	1.34	1.30	1.41	2.37	2.35	2.41	1.60	1.41	1.79
EC (µS/cm)	7.83	7.82	7.84	15.12	15.11	15.13	8.01	8.00	8.02
TDS (mg/L)	15.71	15.64	15.89	30.23	30.20	30.23	15.26	16.53	16.54
TH (mg/L)	3.34	3.33	3.35	10.33	10.30	10.33	3.46	3.46	3.46
Na^+(mg/L)	2.31	2.31	2.32	4.04	4.04	4.05	2.41	2.40	2.41
Ca ^2+(mg/L)	17.45	17.44	17.46	36.54	36.41	36.66	18.48	18.46	18.50
Mg ^2+(mg/L)	7.25	7.23	7.27	48.74	48.46	49.00	7.72	7.70	7.73
NH4^+(mg/L)	0.29	0.21	0.34	0.25	0.21	0.34	0.08	0.04	0.12
NO3^− (mg/L)	0.06	0.05	0.07	1.73	1.69	1.76	0.08	0.07	0.11
Cl^−(mg/L)	12.75	12.69	12.79	38.00	38.00	38.10	12.82	12.82	12.83
SO4^2-(mg/L)	1.28	1.28	1.28	1.58	1.53	1.64	1.41	1.41	1.41
Fe (mg/L)	0.12	0.12	0.17	0.29	0.21	0.34	0.12	0.12	0.17
Zn (mg/L)	0.03	0.02	0.05	0.47	0.46	0.48	0.07	0.05	0.10
Cu (mg/L)	0.48	0.44	0.51	1.08	1.0	1.15	0.67	0.67	0.70
As (mg/L)	0.96	0.64	1.28	1.28	0.64	2.56	1.92	1.28	3.20
Pb (mg/L)	0.83	0.64	1.28	1.28	0.64	2.56	1.92	1.28	3.84
K^+(mg/L)	0.35	0.35	0.3	0.49	0.49	0.49	0.37	0.37	0.39
F^− (mg/L)	1.96	1.92	2.00	2.17	2.13	2.30	2.05	1.79	2.09
WQI	79.05	78.03	80.66	200.83	198.68	204.43	82.99	82.38	88.00

BH1 = Area located 1 km away from WTF; BH2 and BH3 = effluent discharge and administration areas respectively of the WTF.

Table 6. Classification of water quality based on the WQI (Chung et al. 2015).

WQI range	Type of water
<50	Excellent water quality
50–100	Good water quality
100–200	Poor water quality
200–300	Very poor water quality
>300	Water unsuitable for drinking purposes

Table 7. Correlation matrix of water quality parameters.

	pH	EC	TH	TDS	Na^+	Ca^2+	Mg^2+	Fe	NH4^+	NO3^−	SO4^2+	F^−	Cl^−	HCO3^−	PO4^3-	K^+
pH	1.00
EC	.57	1.00
TH	.59	1.00	1.00
TDS	.55	1.00	.99	1.00
Na^+	.55	1.00	.99	1.00	1.00
Ca^2+	.40	1.00	.99	1.00	1.00	1.00
Mg^2+	0.22	1.00	1.00	.99	.99	.99	1.00
Fe	.19	.90	.90	.91	.90	.90	.90	1.00
NH4^+	.13	−.46	−.46	−.48	−.48	−.48	−.45	−.40	1.00
NO3^−	.55	1.00	1.00	.99	.99	.99	1.00	.90	−.46	1.00
SO4^2-	.29	.89	.89	.91	.91	.90	.89	.76	−.76	.89	1.00
F^−	.38	.87	.86	.87	.87	.86	.87	.68	.86	.86	.92	1.00
Cl^−	.50	1.00	1.00	.99	.99	.99	1.00	.90	−.44	.99	.88	.86	1.00
HCO3^−	−.32	−.90	−.89	−.91	−.91	−.91	−.89	−.77	0.77	−.89	−.97	−.90	−.89	1.00
PO4^3-	.08	−.51	−.50	−.51	−.51	−.51	.50	−.51	.61	−.50	−.58	−.56	−.50	.56	1.00
K^+	.67	.98	.79	.99	.99	.98	.99	−.53	.98	−.94	.98	.89	−.58	.98	.94	1.00

Table 8. Summary of principal component analysis loading after Varimax rotation.

	Components		Communalities
Variable	CP1	CP2
pH	.504	.687	.726
Temperature	.751	.462	.777
Turbidity	.986	−.069	.977
EC	.989	.129	.995
TDS	.993	.102	.995
COD	.993	.085	.993
TA	−.793	.560	.942
TH	.988	.135	.994
Ca ^2+	.992	.104	.995
Mg ^2+	.987	.139	.994
HCO3 –	−.948	.253	.963
NO3^−	.988	.126	.993
NH4^+	−.582	.756	.911
Cl^−	.986	.146	.994
SO4^2-	.944	−.262	.960
PO4^−	−.563	.379	.461
Fe	.898	.137	.826
Zn	.995	.068	.994
Cu	.981	−.149	.984
As	.015	−.840	.706
Pb	.010	−.830	.689
Na^+	.992	.104	.995
F –	.903	−.125	.831
K^+	.997	−.009	.994
Eigenvalue	18.063	3.627
% Variance	75.261	15.111
% Cumulative	75.261	90.373

World Health Organisation. 2011. Guidelines for Drinking Water Wuality. Geneva, Switzerland: WHO Publishers.

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Chung, S. Y., S. Venkatramanan, T. H. Kim, D. S. Kim, and T. Ramkumar. 2015. “Influence of Hydrogeochemical Processes and Assessment of Suitability for Groundwater Uses in Busan City, Korea.” Environment, Development and Sustainability 17 (3): 423–441. doi:10.1007/s10668-014-9552-7.

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Data Availability Statement

The author confirms that the data supporting the findings of this study are available within the manuscript