Water & Wastewater Treatment Magazine
Issue link: https://read.utilityweek.co.uk/i/705933
www.wwtonline.co.uk | WWT | augusT 2016 | 31 Simon Kimber sales & MarkeTing DirecTor WPl Difficult effluents industrial wastewater is as challenging as it is varied, which is why careful assessment and customised solutions are required In the know Getting to grips with... industrial effluent DAF plants are o en used where there is a high level of suspended solids and colloidal material, such as waste recycling sites. I ndustrial processes can produce effluents that are challenging in terms of their strength, variability and composition. Careful assessment of the physical, chemical and biological characteristics of the load can deliver a cost-effective and efficient treatment process. Why is some effluent hard to treat? Difficult-to-treat effluent is oen the result of challenging industrial processes which create complex wastewater streams which may have high levels of oil and grease, heavy metals and high bacterial and viral loads that require specialist treatment. Additional challenges may come from a huge range of micropollutants that could also be present. Hard-to-treat effluent may have high biological oxygen demand (BOD) or chemical oxygen demand (COD) as well as high levels of suspended solids. Treating industrial effluent is complex and depends very much on the kind of load and the nature of the process generating the wastewater stream. As specialists in custom- designed wastewater treatment plants, WPL has had to tackle many challenging effluent streams over the last 25 years. How much does the treatment vary from job to job? It is rare to find two industrial wastewater streams that are the same, so treatment will vary from site to site. Because our custom-made plants are designed for each job, the company has found a range of ways of dealing with difficult effluents. A fish farm in Scotland, where the effluent contained a high level of biological material, was assessed as requiring a combination of submerged aeration filter (SAF) plants and dissolved aeration filter (DAF) plants, as well as a series of settlement tanks. At a blood-processing laboratory in England, engineers were able to customise the existing treatment works by fitting fine screens which could filter out troublesome lumps of biological matter. For a municipal waste disposal site in England, WPL created customised chemical treatment which could remove the variety of pollutants seeping from black bin-bags. Which treatment options are available to industrial users? Each case is different when it comes to the kind of treatment an industrial user requires. SAF technology is most suited to biodegradable waste where there may also be high ammonia levels. SAF treatment plants have a small footprint and are economical. If separating suspended solids is the main issue, then a DAF plant may be more effective. DAF plants are oen used in abattoirs, fish processing or other cases where there is a high level of particulate, biological solids. In some cases, for instance where there is a high concentration of hair,