Design of new effluent treatment works in Cleveland has benefited from pilot studies.
'No industrial effluent treatment plant should be designed without rudimentary investigation and very few without having conducted a pilot study,' says Susan Sharpe, senior process engineer with environmental and engineering consultancy Entec UK.
Providing confidence in the treatability of effluent and reducing overall project costs by optimising the sizes of plants are just two major benefits to the purchasers and subsequent operators of a plant, when pilot trials are undertaken.
Pilot plants and treatability trials have played an important role in the design of the effluent treatment works at Bran Sands, on the Tees estuary. This is a central facility treating a range of effluents, including chemical, coking oven and municipal effluents.
When Entec designed and managed construction of the facility for Northumbrian Water, determining the nature of the chemicals contained in these discharges was of critical importance, to identify the chemical interactions between them.
A multi-disciplinary team embarked on a practical assessment at a nearby sewage treatment facility in Billingham. Over a five year period, trials assessed the treatability of the wastes under numerous scenarios, and determined the impact of the major effluent streams on the central treatment works.
Before the trials could begin, a thorough investigation and examination of the wastewater streams was carried out. Entec undertook 'bench scale' studies to determine the biodegradability of an industrial effluent.
The three small self-contained pilot plants set up at Billingham are activated sludge systems and incorporate a biological reactor. Effluents is delivered to site regularly. The site also has the facility to handle special waste for treatability trials and two of the pilot plants on site are equipped with local exhaust ventilation for the safe removal and assessment of potential offgas release.
Many types of effluents were successfully tested at pilot scale and are now being commissioned at full scale.