Reduce Waste, Save Energy

In the US, municipal wastewater treatment plants have traditionally had one focus: treat wastewater and return clean water back to the environment, meeting all regulatory requirements. As cities and populations grow, however, there is an increasing need to focus on the residual byproduct of the wastewater process: biosolids.

Escalating waste disposal and energy costs for biosolids treatment, along with the environmental impact for landfills, have increased the focus on biosolids management and waste minimisation. In fact, the largest costs associated with wastewater treatment are related to the energy and disposal fees for biosolids management. It is estimated that disposal fees will increase more than 10 times in the next 10 years.

"With increasing pressures to municipal governments' budgets, it's imperative to address the energy and waste disposal costs as part of the engineering equation. We're seeing a more holistic approach to the wastewater treatment process. Municipalities and engineers are evaluating the entire wastewater operations, including solids disposal and beneficial reuse of biogas and total energy consumption," said Chuck Gordon, CEO of Siemens Water Technologies.

According to EPA estimates, the quantity of sludge produced in a wastewater treatment plant is approximately 1% of the quantity of treated wastewater, yet sludge management costs can be as high as 40-50% of total operating costs (much of this for disposal).

Technology solution providers such as Siemens are looking at this issue from many different angles. For instance, technologies that reduce biosolids, more efficiently dewater and dry sludge and better capture and convert biogas or compost are providing opportunities for communities to beneficially use biosolids and reduce operating costs, while benefiting the environment.

One recent technology advancement is the Cannibal Solids Reduction System, which can reduce the production of biosolids by 50-80%. Siemens has also seen significant interest in its BioFlowsheet+ Solutions Program, a biological process optimisation program which evaluates specific cost factors such as energy use, labour and disposal. The program integrates several key wastewater operations including biological, solids separation and controls. Dewatering and drying systems can help municipalities reduce disposal costs while simultaneously reducing their energy needs. Siemens systems such as the Centramax dewatering centrifuge, the J-Vap vacuum/drying filter press and the CTD biosolids dryer are three such systems.

Further information about solutions for water treatment is available at http://www.siemens.com/water.