Evaluation of the water quality and toxicity of wastewater in the

carwash industry in City of Tshwane: An analyses of the

preliminary results

By

Ms. Sbongile Phungula

Professor M. Tekere

Mr. K Maphangwa

Tshwane Research Symposium

23 April 2015

Introduction

Car washing consumes large quantities of water

and discharge large amounts of wastewater.

Car washes have received scant attention as a

potential source of pollution globally.

Effluent from car washes has the potential to

contaminate and pollute water resources thereby

causing a threat to the environment.

Many chemical pollutants, dirt and traffic film residue are washed off from cars – can be detrimental to ecosystem if discharged untreated.

Zinc – from tires and brakes, lead – break lining and tyres, engine washing and lead paints, car batteries,

COD, phosphates – detergents, copper –brake dust, Calcium – tyre source,

chromium – yellow road lining marks during heavy traffic, washing of chromium coated parts such as bumpers and wheels.

Gasoline, diesel, motor oil – engine leaks and fuel combustion processes,

surfactants – detergents and cleaning agents.

Objectives

To evaluate the level of car wash activities

and water use in the carwash industry.

To collect and analyse wastewater from the

carwash industries in selected areas in City

of Tshwane

To carry out toxicological studies on the

waste water

To determine the microbial characteristics

of carwash wastewaters

Study area

Sampling sites & ProcedureCar washes in the City of Tshwane were

approached and 6 agreed to participate –different categories Commercial car washesin garages & High density/ illegal car washes.

Denoted CW1 – CW6

7 different bottles collected in each facility once every 3 months

Analyzed at Waterlab (Pty) & Water and Sanitation (Pretoria)

Car wash wastewater Chemistry resultsDeterminants CW1 CW2 CW3 CW4 CW5 CW6

Ammonia (NH4) 1.163 0.605 3.961 2.17 <0.100 12.686

Chloride 55.3 23.3 17.2 36.5 35.2 30.5

Conductivity 67.8 29.7 40.4 37.3 39.4 56.8

Hardness (CaCO3) 257.5 89.8 99.5 69.6 90.7 171.5

pH 7.7 7.7 7.3 7.9 7.8 7.6

Total Phosphate as P 0.553 0.426 1.450 1.009 4.208 0.765

Sulphate as SO4 40.1 13.2 64.7 23.3 8.9 26.6

Kjeldalh Nitrogen 3.75 4.374 7.537 7.194 3.718 13.955

Phosphates as P 0.147 0.026 0.153 0.254 4.179 0.502

Turbidity 23.9 10.4 107 113 108 28.9

Calcium 55.3 25.7 27.7 18.2 20.8 39.4

Red: Exceeding Tshwane limits for pollution in sewage

Blue: Exceeding National environmental standard for discharge of effluent into water or land, 1999

Orange: Exceeding WHO effluent standards

wastewater Chemistry results cont…Determinants CW1 CW2 CW3 CW4 CW5 CW6

Anionic Surfactants 25.6 7.5 41.1 32.8 47.5 38.6

TPH - DRO <1.0 2.3 26 6.7 17 <1.0

TPH-GRO <0.010 <0.010 <0.010 <0.010 <0.010 <0.010

Oil & grease 3 7 24 3 8 18

COD 113 200 416 280 240 160

BOD 20 27 120 81 48 54

TDS 408 232 320 286 842 326

TSS 36 48 181 101 59 54

Chromium <0.003 <0.003 <0.003 <0.003 <0.003 <0.003

Copper <0.005 0.008 0.070 0.035 <0.005 <0.005

Iron 0.038 0.972 1.243 2.285 0.044 0.530

Nickel <0.004 <0.004 0.005 <0.004 <0.004 <0.004

Lead <0.008 <0.008 <0.008 <0.008 <0.008 <0.008

Zinc <0.005 <0.005 0.993 0.788 <0.005 <0.005

Red: Exceeding Tshwane limits for pollution in sewage

Orange: Exceeding WHO effluent standards

Blue: Exceeding National environmental standard for discharge of effluent into water or land, 1999

Car wash wastewater Toxicity results

Car wash wastewater Toxicity results

Determinant CW1 CW2 CW3 CW4 CW5 CW6

Toxicity unit

(TUa)

<1 <1 2.5 8.3 <1 <1

Toxicity test results 30 minutes Vibrio Fischeri bioluminescent test toxicity unit

Toxicity unit Conclusion

<1 Limited to not Acutely Toxic

1-2 Negligibly Acute Toxic

2-10 Mildly Acutely Toxic

10-100 Acutely Toxic

>100 Highly Acutely Toxic

Toxicity units (TUa) (Tonkes and Baltus, 1997)

Car wash wastewater Bacterial results

Car wash activities: Exterior wash & go, Full

valet (exterior, interior, engine, chassis).

One facility recycle & reuse water

Other facilities discharge into sewer system &

drainage

Have no permits for discharging water

Not aware of regulations & discharge limits

No knowledge of quality of wastewater they

discharge.

Use average 600kl water per month

Car wash questionnaire results

The study is ongoing – more samples to be taken to improve quality of results.

Preliminary results suggest wastewater from car washes has some pollutants that has potential to pollute water resources which cannot be neglected.

Most facilities are not aware of the laws and regulations governing Car wash wastewater management.

Although these results might not show much pollution but significant amount of contaminants are generated annually from car washing including residential car washing.

Conclusions

Professor M. Tekere – UNISA

Mr. K. Maphangwa – UNISA

Dr. Mike Silberbauer – Water & Sanitation

Water & Sanitation - Biology lab, Trace lab

& Inorganic lab personnel

Water lab (Pty) for analysis

Water & Sanitation – Resource quality

monitoring colleagues

Acknowledgements

Damha C, Utete B, Soropa G and Rufasha S.B 2014: Potential impact of Wash Bay Effluent on the water quality of Subtropical River. Journal of water resource and protection. 6, 1045-1050.

Lau WJ, Ismail AF, and Firdaus S 2012: Car wash industry in Malaysia: Treatment of car wash effluent using ultrafiltration and nanofiltration membranes. Separation and purification technology. 104, 26-31.

Yasin S, Iqbal T, Arshard Z, Rustan M & Zafar M 2012: Environmental pollution from automobile vehicle service stations. Journal of quality and technology management. 8, 61-70.

References