Water Treatment Portal
By Water Logics

Wastewater blogs

Each month we will select topics on industrial wastewater and extract information from Portal 1 of the Water Treatment Portal to review;

  • how wastewaters are produced
  • the wastewater characteristics 
  • options for treatment and reuse

Industry wastewaters

May 29, 2017
Winery wastewater

 The average amount of water used in wine-making is reported to be in the range of 1,500 to 3,500 litres /tonne of grapes crushed. This is about 2.6 litres /litre of wine produced. Wineries without a bottling line use about 40% less water than the wineries that undertake bottling onsite. Competing pressures on the supply of fresh water, incidences of drought, and increasing limitations on disposal options have resulted in a greater need to treat wastewater to a quality suitable for recycle on these sites. 

 The wastewater produced is complex and can be relatively high in BOD (up to 8,000 mg/l) and suspended solids (up to 700 mg/l). Variations in the nature of the wastewater contaminants can be significant because of the seasonal nature of wine-making. The wastewater usually requires several stages of treatment, including primary solids removal and dissolved organics (BOD) removal. In some cases, conventional aerobic biological processes (eg activated sludge, extended aeration, sequencing batch reactor) can be used to achieve more than 90% removal of BOD. In recent years, the membrane bioreactor has emerged as a suitable process for treatment for recycle purposes. These aerobic processes have to be designed to perform well under peak season conditions, so a modular design with two process trains in parallel are used.

In the case of very high BOD levels, the use of anaerobic treatment (eg digesters, anaerobic lagoons) may be desirable. Anaerobic processes can remove about 70% to 90% of the BOD.  Relative to aerobic processes, the anaerobic processes can better reduce the amount of sludge produced and have a lower power usage. However, they require larger sites and tend to have higher capex costs. In some cases, it may be necessary to follow these anaerobic processes with aerobic treatment to meet low BOD and TSS discharge limits.

Click here to go to Section 1 - Water sources and uses, where you will find more information on the characteristics of winery wastewater.

Click here to go to Section 4 - Contaminant removal, for information on treatment winery wastewater.
March 20, 2017
Pulp & paper industry wastewater
Pulp and paper mills are one of the main water and energy intensive industries as it is the sixth largest water polluting sector. Typically, around 75% of total fresh water supplied to pulp and paper mills emerges as the waste water. Relative to other industries, fresh water usage is very high. Depending on the effluent management system used, and whether water is fully recovered, the quantity of water used to produce one tonne of paper ranges from 2 up to 18 m3. Pulp mills, that produce pulp as a raw material for the paper manufacturing process, use substantial amounts of chemicals for pulping and bleaching. These chemicals finish up in the wastewater discharges from pulp mills. Paper mills produce a range of products such as tissue, newsprint, paperboard and specialty papers. Water acts as a disintegration medium for the raw materials, as a transport member for fibres, and to assist with paper machine operation. In integrated mills, where both pulp and paper manufacturing take place, the wastewaters from each are often combined before treatment is carried out.
 
All of the pulp and paper processes consume a high volume of water, and this water must be of high quality. These characteristics make the paper industry unique. The effluents generated are highly contaminated with up to 250 different compounds. Some of these are of natural origin from the wood (NOM such as lignin and tannins), whereas others are synthetic, such as phenols, dioxins, and furans, and are incorporated into the effluent during the manufacturing and cellulose paste bleaching processes. Pollutants released from pulp and paper mills into the environment pose many problems and physiological impairment. Furthermore, some compounds in the effluents are resistant to biodegradation and can bio-accumulate in the aquatic food chain. Due to the high chemical diversity of the organic pollutants in paper and pulp mill waste water, there can a number of toxic effects on aquatic organisms. 

Click here to go to Section 1- Water sources and uses, where you will find more information on the characteristics of pulp/paper wastewater.

Click here to go to Section 4 - Contaminant removal for information on how to treat wastewater from this industry.



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