World Water Day 2017: Industry and Agriculture Wastewater: Reduce, Reuse and Recycle

World Water Day 2017: Industry and Agriculture Wastewater: Reduce, Reuse and Recycle

In 2011, UK public water supplies provided 62.79m³ per inhabitant of water, of which 27% was used for commercial use and rest for domestic . Of the commercial water used 57% was used for services, 32% for industry and construction and 11% for agriculture, forestry and fishing (and often the use of water in the latter two sectors gets overlook).

Public Water Supply Water Use By Commercial Sector In The UK For 2011
With increasing pressures on water supply and water security as a result of climate change and increasing water consumption, more efficient and sustainable ways of using water are needed. In order to achieve this, the role of ‘wastewater’ should be considered and if this water really is waste? There are three main ways in which wastewater can help to reduce the demands on water supply. Firstly, the creation of wastewater can be reduced or avoided, secondly wastewater can be reused and lastly wastewater can be recycled via its treatment.

Agriculture
There are various ways to reduce the demand for clean water on farms by the creative use of water and matching the water source to the water need. Rainwater harvesting involves the collection and use of rainwater falling onto buildings which would otherwise have gone down the drains, been lost through evaporation, or soaked into the ground. In 2015/2016 farms in England sourced on average 8% of their water from rainwater storage but the majority of farms still get of their water from mains supply.

The Environment Agency in their Rainwater Harvesting: An On-Farm Guide noted that a number of farms in the UK are already using rainwater harvesting to reduce the amount of wastewater created. This includes Haygrove Ltd , a fruit farm in Herefordshire, which collects rainwater from the roof of polytunnels to irrigate the crops grown in containers. The farm harvests around 5,800m3 of rainwater per year and has also noted other benefits such as better soil drainage, improved humidity and a marked improvement in plant health. Oaklands Farm Eggs Ltd in Shropshire has a bespoke rainwater harvesting systems that collects the water into two lagoons where it is treated before being used as drinking water for the 1.4 million hens onsite. By using a rainwater harvesting systems these farms have reduced their demand for clean water from a mains supply.

Industry and Construction (Including Mines and Quarries)
From April 2017, non-domestic water customers in England, like their Scottish counterparts, will be able to choose their water and wastewater providers; water efficiency is likely to become one of the key drivers in decision making.

Many industrial operations are increasingly becoming aware of how water efficient whilst providing economic benefits can also have a positive impact on the environment. Seacourt , a small printing company in Oxford, won the business and industry award at the 2014 UK Water Efficiency Awards for its commitment to dramatically reduce its water consumption. The company has cut its water use by 80% since 2001 . The savings were achieved via new machinery, using waterless printing technology and a companywide drive to save water. In 2011, Coca-Cola Enterprises installed a rainwater harvesting system at its Northampton factory, where a 20,000 litre harvesting system is being used for vehicle washing, warehouse floor cleaning and flushing toilets .

The benefits of avoiding and/or reducing the creation of wastewater through increasing water efficiency and utilising an unused source can be both environmental and economic. Becoming more water efficient, either through adopting a rainwater harvesting system and/or through switching to a new manufacturing process has been shown to reduce flood risk (by managing surface water) and water usage (and therefore the water bill).

When a large site is constructed, there is the potential that sediment laden runoff, which can be considered to be wastewater, may affect the site as well as have an adverse impact on the downstream water environment. The need to manage and treat this wastewater is often a key consideration throughout the construction phase of a project considering it typically takes several months to complete construction and the variable nature of British weather. There are various ways a construction site can treat and manage water entering the construction site:

• Perimeter cutoff ditches can prevent clean water from mixing with sediment laden water and creating even more wastewater.
• Ditches can be installed within the construction footprint to convey the wastewater away from the construction works and towards treatment.
• Straw bales, rock traps and silt fencing in ditches slows the water flow to help suspended sediments be deposited.
• Sediment ponds provide further water treatment before the water is released to the downstream water environment.

Sediment trap with silt fencing
In 2014, Wardell Armstrong were appointed to provide Construction Quality Assurance supervision for the earthworks during the Merchant Park construction and saw first hand how the sediment laden was water use management and treated during its construction.

Mines and Quarries
Sometimes the creation of wastewater is unavoidable. However, there are ways to utilise this water and the first step to recognise that ‘wastewater’ can be a resource.

Wardell Armstrong regularly provides advice and environmental services for our mineral clients. As a result, we have a strong understanding of how water and wastewater are used at mine and quarry sites.

Precipitation, groundwater and surface water that accumulate on the quarry floor is directed into the quarry’s settlement pond system where suspended solids are treated. The water from the settlement ponds supplies both the dust suppressor and the mineral processing and washing plant. Wastewater from the plant is then returned to the settlement ponds for treatment; and the water from the dust suppression reaches the lagoon via surface water runoff. Quarries frequently have a wheel wash facility to prevent mud and dust from leaving the site and most of these are designed so that they self-recycle water and thereby reduce the quarry’s water consumption.

All these water reuse and recycling measures aim to reduce treatment volumes, save money and reduces the risk of dirty water causing pollution. Many mines and quarries are also now incorporating measures to reduce the creation of wastewater such as Northstone (NI) Ltd Concrete Division in cooperating a rainwater harvesting system in their new Toomebridge Tile Plant and the recycling and reuse of wastewater at Drakelands Mine (formally Hemerdon Tungsten Project) in Devon.