Keeping Cabs Clean & Conserving Water

A clean taxi is always appreciated, welcome, and in the case of a DTC cab, it is the norm. Cleanliness, however, is not the issue. The issue is water; it must take an awful lot of water to wash a fleet of some 3000 taxis daily! Manual cleaning uses 150 litres of water per car per wash, and automatic washing half the amount. These are conservative estimates. Washing 3000 taxis manually would mean sending 450,000 litres of water down the drain everyday (that's how much water an average household - a family of six members - in the UAE would use in five months!); 164 million litres (43 million gallons) a year!

Imagine if the 450,000 litres of water required for a day's cleaning were treated, stored and reused for cleaning taxis - in a constantly operating water recycling system that utilises the same water day after day until it is time to change the entire supply. Say, after six months? Maybe, nine?

Also imagine if the car wash water were being treated biologically, using grease-consuming microbes: bacteria, naturally present in the water, that are allowed to thrive, subsist on a diet of dirt and oil and, in the process, purify water for subsequent car washes. No toxic chemicals; no threats to human health and the environment!

Sounds good doesn't it? But the really good part is that one doesn't have to imagine it. It's actually happening at DTC's Al Qusais complex, run by EPPCO. Here, DTC taxis are being washed using a biological-physical water recycling system called ''System Iller,'' (named after Germany's Iller River, a tributary of the Danube); a system based on the biological self-cleansing mechanism prevalent in natural water bodies. The mechanism has been successfully used to treat sewage for several years. This is how: First, primary treatment, a mechanical process that uses screens to filter out debris, and allows suspended solids to settle down as sludge; followed by secondary treatment, a biological process in which aerobic bacteria are used to remove up to 90% of biodegradable wastes. These same processes have been adapted by Germany's Weikmann Company to develop System Iller for car (and other vehicle) wash lines.

To get back to DTC's Al Qusais complex, where the System Iller has been installed by Dubai-based Salam Enterprises. Prem Lal, operations manager, environmental division, Salam Enterprises, explains to this writer how the system is working. There are 12 car-washing bays where taxis are being manually spray-cleaned using high-pressure water jets. The runoff water contains various impurities - grease, wax, sand, dust, detergent, oil and some heavy metals (minute traces of zinc, lead and copper from batteries). Most of these (other than heavy metals) are biodegradable. To work effectively, System Iller requires only biodegradable substances to be used in the vehicle wash area. This means that detergent, shampoo and wax used in washing and polishing DTC taxis have to be 100% biodegradable. And so they are, because a ''multi clean, multi purpose, fully biodegradable detergent'' is being used.

Wash water drains off through vents on the floor into pipes, and into an underground interceptor tank with three chambers where, in succession, solids settle down, oil is separated, and water aerated.

Next, water moves into a ''hydro-cyclone'', where rapid swirling removes any remaining solid particles before it is pumped into a ''bio-reactor'' (a tank) for biological treatment. Inside the ''bio-reactor'', bacteria cling on to a ''bio-lawn'' that provides a breeding ground for them. Water constantly circulates while bacteria feed on the muck, dissolving and transforming the car wash pollutants into hydrogen, carbon and purely biological substances. Treated, in this benign manner, to a quality fit for reuse as car wash, water is pumped into a storage tank and is, once again, ready for spray cleaning taxis. It's a cyclical system (called a closed loop system). The only fresh water that is needed on a regular basis is that which is lost through evaporation or the careless mislaying of pipes by workers.

Sludge is a by-product in System Iller. The build-up of dead and decaying microbes in the bio-reactor, solid particles in the hydro-cyclone and other similar deposits are directed into a single area - the first of three chambers in the underground interceptor tank - for quick and easy collection. From here sludge is collected periodically (by Trashco) and, probably, landfilled. It could, however, be used as fertiliser.

Sounds hi-tech? Well, it may be so. But you get the drift. So, when we next ride in a DTC Toyota Camry, Mitsubishi Gallant, Chevrolet Lumina or any other, we can derive comfort in the fact that our cab's douche water is recycled! And wonder whether the car wash facility (there are hundreds in Dubai) that we patronise for our personal car is recycling its water at all, or not.

NATIONAL NEWS

Wildlife Marine turtles The Environmental Research and Wildlife Development Agency (ERWDA), Abu Dhabi, has set up a marine turtle breeding and research unit on Qarnain Island, Abu Dhabi, which is a natural nesting habitat for endangered green and hawksbill turtles. While green turtles have, since last year, been fitted with satellite tags to track their migration routes, it is only recently that transmitters were fixed on hawksbill turtles. One of two hawksbills so fitted, has been tracked back to Qarnain Island to lay eggs for the second time. At the ERWDA unit, some turtle hatchlings will be reared in specially designed fibre glass tanks and, upon maturity, released into the Gulf after being tagged. ERWDA'S research will lead to recommendations on marine turtle conservation. Hawksbill turtles occur wherever there are coral reefs, which suggests a range including much of the Gulf of Oman and Arabian Gulf coasts of the UAE. Most have been sighted near the shallow, offshore coral reefs of Abu Dhabi. Dugongs An aerial survey and satellite tracking project on dugongs (aquatic, herbivorous mammals, also called sea cows) was initiated by ERWDA in June '99. It will study the species distribution pattern and track their movements with a view to formulating a national dugong conservation plan for the Gulf waters, including the selection of sites to be designated as marine protected areas. The Arabian Gulf hosts the world's second largest population of dugongs. In the UAE, they mostly inhabit the shallow waters around the islands of Murawah and Bu Tina, west of Abu Dhabi, but their range extends further west to the border of Qatar and beyond. There have also been occasional sightings to the east around Jebel Ali, Umm Al Quwain and Ras Al Khaimah. Once widely found in coastal waters from the Red Sea and the Gulf to eastern Africa, the Philippines, New Guinea and northern Australia, today dugongs are seriously threatened on account of habitat destruction, over hunting (they are killed for meat, hides and oil), entanglement in fishing nets and consequent death by drowning. Air-breathing mammals, having to surface every six to 10 minutes to breathe, dugongs are herbivores that feed mainly on sea grasses and marine algae. Aerial surveys of dugong habitats prove that the species, despite protection by law throughout most of its range, has disappeared in many places, and is rapidly disappearing in others. Only the Australian coasts have an estimated population of around 5000, followed by the Arabian Gulf.

LETTERS

We have this letter from a concerned hotelier: I am working in the hospitality industry in Abu Dhabi for the past three years. In the industry, I see a lot of mishandling of wastes, such as oil, which is used in deep fat fryers and used soaps from guest rooms. I would like to know the proper method of disposal of such items or any way that they can be recycled so that they can be made use of in the hotel. I have read somewhere that oil can be converted to soap for use in floor cleaning agents. I commend Earthsense for the work it is doing in spreading the message of caring for our mother EARTH! Response: I am aware that hotels in parts of Europe store their used oils in tanks. These are periodically collected by authorised oil recycling companies. This is the norm and a legal requirement. In fact, most hotel kitchens have a direct outlet to their oil storage tanks. As far as soaps in guestrooms are concerned, many hotels have done away with the wastage problem by using soap dispensers. Those that use soap cakes are known to pass the used ones on to charitable organisations for export to parts of the world where these may be needed e.g., war situations, refugee camps and so on. From Dr. Abubakr Al-Saggaf, general manager, Environmental Services LLC, Fujairah Back from my trip abroad, I found the Gulf News Friday Magazine of 11 June 1999, with your very well written article about marine pollution and its prevention. Besides our independent appreciation of the professional style you maintained in all what you have written, I would like to express our thanks for the positive statements you quoted about our project ECOREF. Response: Thank you for your appreciation. I wish the ECOREF project all success and hope to hear from you when it becomes operational.

WHAT ON EARTH CAN WE DO? Wash a car from a bucket of soapy water and use the hose for rinsing only. Use a commercial car wash that recycles its water.

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