Grease industry wastewater usually refers to the wastewater discharged from edible oil refining and processing unit.It mainly includes extraction wastewater,refining workshop hydration wastewater,alkali refining wastewater,cooling water and ground washing water,etc. Different process lead to different pollution loading,COD:2000-7000mg/l,BOD:1500-2500 mg/l,oil:1500-2500mg/l;Wastewater’s grease composition includes suspension oil,emulsified oil,dissolved oil,phospholipids and gleditsia sinensis lam soap.And its suspended matter content is also quite high.Another characteristic of the wastewater is C:N:P ratio is moderate and the biodegradability is good.

Livestock and poultry breeding wastewater is mainly from animals manure and house washing,it belongs to high-pollution wastewater.And the key of wastewater treatment is how to remove the ‘three high’(high COD,high SS,high NH3-N) in water. According to the characteristics of wastewater,we provide three solutions:(1) Comprehensive utilization of energy,the purpose of this solution is to get the maximum economic benefits.Through anaerobic fermentation to make full use of biogas,biogas residue and biogas fluid, biogas is used for power generation and recycled back to farm,biogas residue and biogas fluid are good organic fertilizer; (2)Energy-saving and emission-reduction,the solution give priority to energy-saving and emission-reduction,and economic benefit is complementary.Through pretreatment and improved biological treatment to remove the SS, COD and NH3-N of wastewater,and make the wastewater achieve the standard of direct emission.(3)Wastewater recycling,in view of the long breeding cycle and intermittent emission characteristic,we choose the following craft:‘pretreatment+comprehensive treatment+ disinfection’,effluent can be recycled for animal house washing.

Food industry wastewater is mainly from raw material cleaning(mainly includes massive suspension),producting(mainly includes massive organic matters),and forming units (mainly includes various food additives).Water quality and quantity fluctuate greatly due to various raw material and production.Its main pollutants include:solid matters floating on wastewater,such as vegetable leaf,peel,frittered meat,etc;fat,protein,starch and colloid material aerosolling in wastewater;acid,alkali,salt and carbohydrate dissolved in wastewater;mire,sand and other organic matters entrained in raw material;pathogenic bacteria .etc.Food industry wastewater’s organic and suspended matters content is high.It generally is perishable and non-toxic.

Printing and dyeing industry wastewater discharging volume is big,and contains high concentration pollutants.It’s mainly from dyeing and finishing section,includes desizing,boiling,bleaching,mercerizing,dyeing,calico printing and finishing wastewater.Pollutants mainly are dirt,salt,oil and lipid in textile fibers,and processing project additional dyes,slurry,surfactants,additives,acid and alkali,etc.It’s main features are large volume and complex composition,high organic matter content,COD is 800-2000mg/l,B/C ratio is low,and biodegradability is bad,high alkaline,chroma and temperature,water quality and yield fluctuate greatly,containing large amount of additives and surfactant.

Paper industry wastewater is divided into three kinds,black liquor,intermediate wastewater and white water.At present,intermediate wastewater is the focus of paper industry wastewater treatment.It mainly derives from scrubbing,screening and bleaching units,composition is complex,contains high concentration recalcitrant composition,such as lignin,cellulose and resinate,these make BOD,COD,SS,chroma quite high and biodegradability bad,so the wastewater is difficult to treat.

“Reclaimed water” is relative to feedwater and drainage,it refers to the domestic wastewater or industrial wastewater treated by special technology to achieve the recycle standard,and applying to virescence,industrial water,fire protection,car washing,roads and toilet flushing,etc.,so as to achieve the saving water purpose.